402 LS2 TT - the saga continues

[choppo]

Ive started this thread not necessarily as a pissing competition (although Ill do some of that :yep: in jest!) but as you will see ive ended up with an issue, that the answer, may well be interesting to some of you force ind guys ? maybe ill even get some constructive input!

Background ? with much thanks to Sam and his boys :bow: , yesterday we installed;
New 402ci LS2 iron motor (btw, yes there is a LS1 and LS2 iron 402), big heads from the US, massive sump, all the good bits and expertly built by the Man himself with precision and the finest of clearances
Cam ? 228/230 at 112 ? Not because it?s the best for turbo applications, but because we new knew the engine was going to produce more than enough grunt, I could easily sacrifice some power for the idle attitude this cam would give ? my call this one so lets not argue this please
Turbo?s ? sent my original Garrett turbos to the Sydney Garrett dealer GCG (or CGC??) for modification. As an example, the original turbos feed a standard LS1 at 12.8psi at 3000rpm and struggle to keep up at 6500rpm with 8psi ? producing around 420rwkw. On my standard LS2 they made around 440rwkw at around same boost. So it was obvious they we going to need some serious mods to keep up with a high flowing 402ci. Ill post the specs tomorrow if anyone is interested in what they ended up as.

Anywho?.. yesterday Saturday, after days and nights of the usual no sleep to make the Drag Day we started it up. Almost got a boner at the sound of it chugging away at idle and we were only minutes away from its first dyno run. I confirmed with Sam that the actuators were set by GCG at 7.8psi (call it 8psi) so that later on I could install a boost controller and play with the boost levels. This 8psi would give a good base line anyway.

So on the dyno, half a tonne of weight in the back (exaggeration), oil OK, water OK all ready. Start ramping the car up at 2000-2500rpm to start dyno run. Decided to do the first run in 4th gear as we feared a bit of wheelspin ? sounds reeeealy :drool: good at this point. Sam?s now gets into it???...........HOLY F**?N SH*T :shock:, the thing instantly climbs up to the very top of the rollers, slides across the dyno in a fit of wheelspin/tramp, dyno numbers fly skywards as the car tries to launch out of the workshop ? I have by now jumped into the nearest bunker for cover amongst the unbridled chaos appearing before me. Ive seen cars dyno?d before, but man I crapped myself :lmao:. Sam lets off at high 4k RPM.

OK, Sam sits in the car un-fazed by all this but with a steely look of concentration
Sam says ?warble?. blah..,...fu*k?n this and that, furptpjald? he yells to me.
Now deaf, I yell ?what, whats up???? :confused: ?

So, once we bystanders pick our jaws up off the ground from what we just saw, some scramble for the tie down straps for the next run, i go over to the computer for analysis and work out what Sam is concerned about and why he shut it down so quick. Well, why he shut it down early was apparent to me, as the thing was a wild animal unleashed and going insane :bravo: ??.At 80% tps, at high 4000rpm, 600rwhp :eek: (440rwkw) with insane torque readings, OK?. but wait for it??. 15psi+ @ just under 5000rpm where he got off the loud pedal. What the hell is going on. The actuators have been confirmed as 7.8psi?. I can believe 9spi or even 10psi somehow, but 15psi+?? WTF?? :confused:

Now a massive thanks to Sam at this point. The MAP readout on the dyno is a small square amongst a million other figures shown on the screen AND I had told him the wastegate actuators were 100% confirmed as 8psi jobbies ? he shouldn?t have had to pay much attention to it. But, amongst the apparent chaos while the car was trying to rip itself from mother Earth, tramping across the dyno, screaming it tits off ? Sam had the composure to spot this MAP reading and get off the loud pedal as soon as it started spiking. Mind you this was not a slow progression from 8, 9, 10, 11, 12,13, 14, 15psi over a second or two?.. it was 3000rpm slight load and 8psi, 3800rpm (an instant later) the MAP was skyrocketing up past 14psi!!! What the hell was happening??? Sam?s attention to detail, composure and decades of experience just saved me a brand new engine.

So, a thorough check of all boost hoses etc few adjustments to this and that ? yep ,nothing wrong on our side ? we test the actuators, yep opening at 8psi. We tentatively try a few more runs again at low rpm.

Same results, with all the timing removed for safety this time, massive boost spiking (still around 13-14psi) despite the actuators set at 8psi. Pack up tools (it getting late on Sat night) ? resigned to the fact we are not going to make the Drag Day and I need to talk with GCG on Monday.

My guess (and it is an un-educated guess) ? the internal wastegates are too small to bleed off enough exhaust gas from the hiflow 402. The gates are obviously fully open, but can?t physically divert enough exhaust away, so the turbine keeps filling therefore producing endless boost (well 15psi that we know of, and it wasn't slowing!). Anyone had experience with a wastegate issue like this?

Third time ive mentioned this, but massive thanks to Sam and his guys for their hard work and expertise over the many months leading upto today.

Will keep you updated if interested.

[seedyrom]

solid is facing the same thing in adelaide.

You're not running a boost controller either ?

[10sec_rx7]

time for twin 38mm external gates...

mine does the same thing but it only creeps to 11psi off the 7psi springs,

[choppo]

solid is facing the same thing in adelaide.

You're not running a boost controller either ?
Ive got the APEXI sitting in the back of the car (in the passenger seat:) not connected.... As far as i know (which is little:waving: ), boost controllers only adjust UP from the base sprung actuator spring.... i.e. does nothing for me with this problem.

My 1st question on Monday is going to be (although i previously asked GCG b4 i gave them my turbos), why can't i have zero boost? or 1psi, or 2psi boost.... yeh that sounds strange, but why not? Then i can use a boost controller to run 2psi at 2000rpm, 6psi at 4000rpm and so on..... The problem is it seems all the 'boost controllers' are based on 4cyl/6cyl application looking for heaps of boost over std... not actually a boost controller but boost 'upper' - which they are.

[choppo]

time for twin 38mm external gates...

mine does the same thing but it only creeps to 11psi off the 7psi springs,

Id love to have a chat with ya! Interesting issue that ive heard nothing about???

[Delft Maloo]

what turbo specs are you running now choppo, if its not a secret that is.

[choppo]

These are the questions i asked and the figures (some of them) i got back....
COMPRESSOR
Wheel diameter =
Wheel inducer size = 54.95mm
Wheel exducer size = 76mm
Trim = 52Trim
A/R
Compressor Map

TURBINE
Wheel diameter
Wheel inducer size = 60mm
Wheel exducer size = 54.98
Trim = 84Trim
A/R = 1.00a/r
Turbine Map

Regards,

MARK LARDEN
Sales Manager

The bits missing im still waiting on.........

[BOMI]

Hey Choppo! That was a ripper of a yarn, I felt like I was in the workshop with yas!!

I watched a video of the Engine Dyno fire last year that Justice put up, that was freaky too, I cant imagine that this episode would have had the pooper doing the 10 cent 50 cent dance :lmao:

Hope you resolve it real fast mate :thumbs:

Troy :)

[10sec_rx7]

that compressor is almost identical to mine, they work a treat!

if you exhaust housing is a 1.00ar that wont be helping you problem, if you went to a .83 it would probably solve the problem but will cost you 10-15hp,

boost control is all about wastegate size vs exhaust back pressure,
the larger you rear wheel and housing a/r you have the less back pressure you will have and the larger wastegate you will need, the smaller the housing you have the higher the back pressure and the more gas that will pass through the gate etc

with that housing you may need to go some 44-48mm gates as your back pressure will be very low,

you have 3.35 or so L of engine trying to pass through a 20mm hole to control the boost, its just not going to happen, this is where someone who has a lot of exprience with turbo sizing etc is a must.

we went through all these problems 10 years ago on our mazdas when running small exhaust manifold runners and a large exhaust housings to get the boost response we wanted, even a 42mm gate would not pass enough gas to keep the boost down, we ended up running a 60mm gate on daves rx3 and changed manifold on mine to a larger runner to get the back pressure down, once doign that we could hold the boost solid at 11psi

[choppo]

that compressor is almost identical to mine, they work a treat!

if you exhaust housing is a 1.00ar that wont be helping you problem, if you went to a .83 it would probably solve the problem but will cost you 10-15hp,

boost control is all about wastegate size vs exhaust back pressure,
the larger you rear wheel and housing a/r you have the less back pressure you will have and the larger wastegate you will need, the smaller the housing you have the higher the back pressure and the more gas that will pass through the gate etc

with that housing you may need to go some 44-48mm gates as your back pressure will be very low,

you have 3.35 or so L of engine trying to pass through a 20mm hole to control the boost, its just not going to happen, this is where someone who has a lot of exprience with turbo sizing etc is a must.

we went through all these problems 10 years ago on our mazdas when running small exhaust manifold runners and a large exhaust housings to get the boost response we wanted, even a 42mm gate would not pass enough gas to keep the boost down, we ended up running a 60mm gate on daves rx3 and changed manifold on mine to a larger runner to get the back pressure down, once doign that we could hold the boost solid at 11psi

Many things here...
1. i actually went to GCG as they are the Garrett dealer in Sydney and asked them to size them corrrectly for the new engine - i didn't say " ive only got $200, so do the best you can".... in fact i said "do it, send me the bill" - They did and they actually cost more than new turbos's :toetap: :toetap: !!! If this turns out to be an incorrectly sized turbo issue... :flame: :flame: :flame:
2. thankyou very much re; history and tech bits
3. im a MASSIVE Mazda fan. As a 18yo, i used to build them.... had a SIII '84 RX7 that i fit a Series V turbo into - all done at home by myself. :yep:
Then there is the genuine '71 coupe RX3, all self built... as you would know (back in the day) the 15' gold B45's on the gunmetal grey coup body (painted myself in acrylic of all things!) with a PP (again built by myself) - ill post the old photos up if i can find them.
Anyway, will be interesting to see what the 'Garret Expert' says in the morning!:up2sum:
4. You are someone i wouldn't mind meeting up with... you are CHE are you not?

[choppo]

Hey Choppo! That was a ripper of a yarn, I felt like I was in the workshop with yas!! Troy :)

There was obviously a bit of 'poetic license' in there, but the facts are as stated....too much hp aint always great.

[RedVYIISS]

Choppo,

Your story mirrors mine first time Sonny ran mine up. Mine however was easy fix as F1 Performance put the wrong spring in my wastegate. Sonny's quick reactions are what saved my engine.

And yep, Dale & Dave are the CHE boys. Pop across, well worth the visit and plenty of F/I experience there. (I should dig up my old install thread, the CHE boys did my install for me).

[10sec_rx7]

Many things here...
1. i actually went to GCG as they are the Garrett dealer in Sydney and asked them to size them corrrectly for the new engine - i didn't say " ive only got $200, so do the best you can".... in fact i said "do it, send me the bill" - They did and they actually cost more than new turbos's :toetap: :toetap: !!! If this turns out to be an incorrectly sized turbo issue... :flame: :flame: :flame:
2. thankyou very much re; history and tech bits
3. im a MASSIVE Mazda fan. As a 18yo, i used to build them.... had a SIII '84 RX7 that i fit a Series V turbo into - all done at home by myself. :yep:
Then there is the genuine '71 coupe RX3, all self built... as you would know (back in the day) the 15' gold B45's on the gunmetal grey coup body (painted myself in acrylic of all things!) with a PP (again built by myself) - ill post the old photos up if i can find them.
Anyway, will be interesting to see what the 'Garret Expert' says in the morning!:up2sum:
4. You are someone i wouldn't mind meeting up with... you are CHE are you not?

i myself would not run that size turbos with internal gates on that size motor, it is asking for trouble, what you have there is 1000hp+ of compressor and over 6.5L of motor trying to pass through a 20mm hole, its just not going to work

what you are suffering is the same thing the old S4 rx7 used to suffer when you put a high flowing 3in exhaust on it, hence the reason they went to twin flap internal gates on the S5 motors..

would love to see some pics of your mazdas mate, ive got a few lying around of mine from back in the days,

yep im at CHE, pop in and we can have a chat

[NickS]

That's quite a story choppo ... hopefully you can have everything up and running by the 12th of August !!!

Good luck getting it all sorted, 90% of this tech talk is going straight over my head.

:lol:

[choppo]

That's quite a story choppo ... hopefully you can have everything up and running by the 12th of August !!!

Good luck getting it all sorted, 90% of this tech talk is going straight over my head.

:lol:

There is no two ways about it - im making the 12th Aug!!! - even if i have to push it down the strip :yep:
All the tech stuff is real interesting i recon - thats why i started the post as i have not heard anything on this on any forum... off to GCG now - info in hand (thanks 10secRX!) to see how much they know! Will post result tonight and see what you recon.....

[choppo]

Well looks like twin 44mm Tial external wastegates are the go...... the trick now will be to remove the internal wastegate flap, bore out the before mentioned area that used to house the gate - to more than 44mm - then make up a new exhaust manifold to suit the new external wastegate etc. Ill try to get a photo or two of before/after.

[DaveHAT]

Chop,

Can you translate some of these posts into english for us dumbasses? :confused:

It all sounds complicated to me but I understand the numbers to a point ... especially the 1000hp of compressor ... :shock:

In summary I suspect we will see numbers from this config that can only be measured in increments such as:


Shit tins
Holy crap


and


arseloads


If need be I will help you tow it down the 1/4 on the 12th as long as you can get it to idle I reckon those turbos will generate enough thrust to push both of us into the 11s ... :lmao:

[10sec_rx7]

Well looks like twin 44mm Tial external wastegates are the go...... the trick now will be to remove the internal wastegate flap, bore out the before mentioned area that used to house the gate - to more than 44mm - then make up a new exhaust manifold to suit the new external wastegate etc. Ill try to get a photo or two of before/after.

ok here is what to do,

remove the exhaust housings off the turbos,
hold flap closed and weld the flap shut, this will stop leaks etc,

just bore a 50mm hole in your manifold just below the inlet to the turbo, run some thick walled pipe and mount to wastegate,

BTW i can probably get the tial gates cheaper than GCG will sell them to you

[choppo]

Tiger, just because you asked……. (and i hope the pics get inserted!)
Now before anyone gets on here shit canning me – I AM NOT A TURBO EXPERT!!! Im just trying to give a real ‘laymans’ version of what I have only just learnt over the past few months via trial and error. The real place to go see all the in’s and out’s of turbos is the Garrett website www.turbobygarrett.com. It has ‘basic’, ‘intermediate’ and ‘expert’ sections which are real great info! Also here I am not using the correct technical name for component – as before go to the Garrett site for these……

So at the risk of having my head bitten off, here is a simple version of what I am talking about. Please feel free to add/confirm/discuss. This is all in the name of basic learning (and I had a spare 20min to try to post pics for the 1st time!).

Firstly you have the internal wastegate as seen in attachment #1 (the pic is actually missing the little ‘flap’ that opens and closes controlling the boost). All the internal wastegate is doing is allowing the exhaust gas to bypass the turbo exhaust wheel (the big hole!) when you want and as desired. Without any exhaust gas being able to bypass the turbo exhaust wheel, the turbo will simply spin, and spin, and spin to max rpm and hence boost to the max. So now if you say you want 7psi boost, the ‘wastegate’ or ‘flap’ simply opens a little bit (or alot as the case may be) to only allow the compressor wheel to get enough exhaust gas to spin to 7psi. Obviously if you want higher boost it will simply open later and/or less resulting in more exhaust gas to the wheel = bigger boost.

See attachement #1
http://www.trackchat.com.au/media/data/540/medium/1_0001.jpg

Now my problem. The wastegate hole you see above is actually quite big. Mine is only the size of a 20c piece. So you have a BIG turbo trying to bypass A LOT of gas through a tiny hole. Hence what 10sec said, a 1000hp turbo needs a big pipe to bypass the gasses, a 200hp turbo will probably get away with a 20c piece bypass….. So the problem I have is the waste gate flap is actually FULL OPEN at very low rpm/low exhaust flow trying its best to bypass those exhaust gasses. As my rpm’s rise and the exhaust volume gets greater, the tiny 20c hole simply can’t bypass enough gas making all the other exhaust gas flow through the turbo exhaust wheel thus making more boost and more boost and more boost – it simply can’t bypass enough. Yes, you can make this internal waste gate at bit bigger, but it still want be big enough.

Solution (I hope!!!)

Permanently open the ‘flap’ as seen in the first pic THEN ream the shit out of the surrounding cast to make the hole bigger! i.e. neatly and professionally mill the casting so that the hole is much larger. So we would be going from a 20c piece sized hole to a hole to match the ‘external wastegate size’. i.e. you saw 10sec mention 38mm/44mm waste gates. That’s simply the size of the hole it will now bypass via. Now at this stage you must be thinking gezzzz that’s a big difference in size – exactly – and its exactly why I have my problem now. Like trying to push that massive ‘the day after’ grog bog out, when you have massive haemorrhoids closing your chute up – it aint gonna happen! Solution – make a incision in you abdomen, put a big 44mm pipe in there that will take ? the turd, let the other half go out the normal way!
So now I need a separate pipe with the new external waste gate plumbed in (i.e. it is not actually part of the turbo) that goes from the new ‘reamed out’ bypass hole, through a controlling mechanism (waste gate) into the (exhaust pipe). This is where the new ‘bypass’ gasses will flow. So the attachment #3 is a pic of what I have to do. You will note these are 38mm external waste gates.

See attachment #3
http://www.trackchat.com.au/media/data/540/3_0001.jpg

As 10sec noted today, there is another way this can be done i.e. simply get a pipe from before the turbo (exhaust manifold) connected in a loop directly to the exhaust with an external wastegate inline. Get rid of the internal waste gate/path all together. Unfortunately as I don’t have any room, I cannot do what 10sec mentioned – wish I could it would be a hell of a lot easier and probably much better as the bypass track is nice and unrestricted and smooth. You might find the TT kits with the turbo’s in the engine bay will be a lot easier to do the way 10sec mentioned.

Did all that make sense or was it a waste of time!!!

[seedyrom]

makes sense.

Especially the bog part :)

Is that why small capacity engines with big turbos bog down?

anyway ... so the big question is, are Garrett coming to the party ?

Or have they fobbed you off with a "we stand by our decision - we are Garrett we can't be wrong" type response?

[choppo]

makes sense.

Especially the bog part :)

Is that why small capacity engines with big turbos bog down?

anyway ... so the big question is, are Garrett coming to the party ?

Or have they fobbed you off with a "we stand by our decision - we are Garrett we can't be wrong" type response?

Actually they are selling me the Tial 44's at 'cost' - ill check with 10sec via PM as to price as he was kind enough to offer me a super cheap price - much appreciated 10secRX!!!!
Still the whole exercise is gonna cost me a bit - would have liked to know before hand...... :toetap: ...... also, i am amazed there is no more science/calculations going on with this from the 'experts' at GCG. Despite all the compressor maps etc etc etc, they still seem to be on the 'that should work' path.... strange as i though it would be more scientific from the Garrett guys.:(

[NickS]

This is an awesome thread Steve ... I'm learning heaps. Don't worry about "getting your head bitten off", the whole point of Track Chat was to get away from all that stuff, your posts in this thread are fantastic.

:bravo:

Thanks for taking the time mate.

[Delft Maloo]

put very nicely mate. the whole wastegate thing can be a bit difficult to explain sometimes. im lucky to be doing a single kit mounted high up so ill be running my manifold and wastegate the same as dale said. i actually talked to the guys at turbosmart about their wastegates and the fellow i talked to was quite helpfull about details and setup information, but when you have got more than expericed members on here such as 10secrx7 help isnt to far away and the rest of the guys at castle hill exhaust are a great bunch too. you wont go wrong with any advice dale has to offer.

[choppo]

put very nicely mate. the whole wastegate thing can be a bit difficult to explain sometimes. im lucky to be doing a single kit mounted high up so ill be running my manifold and wastegate the same as dale said. i actually talked to the guys at turbosmart about their wastegates and the fellow i talked to was quite helpfull about details and setup information, but when you have got more than expericed members on here such as 10secrx7 help isnt to far away and the rest of the guys at castle hill exhaust are a great bunch too. you wont go wrong with any advice dale has to offer.
Yep -well said - im really keen to keep this as simply a 'telling the story' thread as much as possible. Yeah im gonna make mistakes, say the wrong thing but until 2mths ago, i didn't really know the ass end of a turbo either! Hense why im posting on TrackChat as i think there is a general inclination to help and inform rather than s**t can each other. Id really like to be able to go out to CHE, Sonny, anyone...... and/or the drags with them without any hessitation or anamosity - just because i got my work done at another shop, who gives a crap! Just want to meet, hang and learn with like minded people.

[10sec_rx7]

thats the way it should be mate,

most people will know that Sonny and myself talk just about every day, we get parts of him and he gets parts off us.. the more people that work together the better

[choppo]

thats the way it should be mate,

most people will know that Sonny and myself talk just about every day, we get parts of him and he gets parts off us.. the more people that work together the better

:yep: :bravo: :bravo: :yep:

[OZY 260]

this thread is great choppo, thanx for sharing your information with us all, please do continue to keep us informed

cheers brett

[choppo]

this thread is great choppo, thanx for sharing your information with us all, please do continue to keep us informed

cheers brett

Shall do - thanks for the encouragement - currently looking at removing turbos Thurs-Fri. So early next week more photos etc! :) This means ive got a week to get my head around the APEXI boost controller - thats a whole other story!

[DaveHAT]

Thanks for the post previous Steve ... :bravo: it certainly did help. I still don't get a lot of this turbo stuff but the previous post was brilliant. :yep:

Not to jump on the band wagon and blow the old trumpet ... but as others have said ... who you go to and where you get your work done does not matter one IOTTA here at TC. We have people (thankfully) from outside of LS1 as members as well and we don't want this forum spoiled by the nonsense of workshop badgering and so forth. There's more than enough axe grinding and crap going on elsewhere.

In short ... keep it up Steve, this sort of stuff is great. :bravo:

[choppo]

Damn.... not as easy as the nice little pic i posted before! My turbos are rotated differently to that shown before. Back to the chalk board!

[Sonny@AutoWerks]

Hey choopoo !!!!

That thing sounds insane !!! gonna be quite a torque monster once you sort out the little bugs !!!! 600rwhp ! awsome !!! well done :yep:

regards sonny

[choppo]

Tks Sonny! - worked out we have to revert back to what Dale described earlier in this post i.e. new pipe from exhaust manifold thru waste gates rather than the nice little pic i posted! Not much bloody room though.... should be done mid week so hopefully all goes well!

[MrKeen]

Any updates about your ute?

[choppo]

Any updates about your ute?

Actually heaps has been happening :yep: - just didn't want to overshadow Dales and Deft's great efforts over the past weeks!
Anywho.... got the Apexi in and wired up finally - looks good if nothing else! :bravo:
If you have been following the earlier posts, my wastegate issue is a rather complex one and after trying just about everything in the book to try and get twin 44 externals on in various ways, we have embarked on some 'experimental' turbo engineering utilising the internal wastegate method. Never heard of it being tried before, don't know if it's going to work either - and is a bit radical i suppose..... and should be finished by the weekend (which probably means next month!!). Want to know more?



























When i get home and put bubs to bed ill try to write some explainations!:whip:

[MrKeen]

and should be finished by the weekend (which probably means next month!!). Want to know more?




I hope yours get done then mine might get finished.:whip:
Why is this happening to your kit? Is it just a fauly component,poor design.....its not something I have heard happening with other TT kits? Not trying to start any shit just curious why this is happening to you.

[Delft Maloo]

mate dont hold off your progress updates due to me. your build and dales is what makes me even more excited in building mine. when i get this one finished im going to build another single kit and my own custom twin kit just for the fun and learning experience. Plus theres going to be one more tt kit that ill start on eventually and that will be for my Eh holden that has a CHEV V6 in it, this one shall be a breeze its got none of that fancy shite in the engine bay taking up space, converting it to fuel injection and electronic ignition will require abit more expertise than i have atm.
keep it coming choppo were all excited in what your doing.

[choppo]

and should be finished by the weekend (which probably means next month!!). Want to know more?
I hope yours get done then mine might get finished.:whip:
Why is this happening to your kit? Is it just a fauly component,poor design.....its not something I have heard happening with other TT kits? Not trying to start any shit just curious why this is happening to you.

Hi Keen ? no offence taken. Infact I would encourage that type of question from more people so long as it is meant in the search of knowledge and understanding which yours is.
Ive had my TT kit for around 18mths. Fitted by AutoTech in Sydney (who were GREAT btw). On my stock LS2 6ltr it cranked out 400 - 420rwkw conservatively tuned (it actually got 439rwkw on the 3rd run without trying) - mind you this was 2yrs ago.... .... This is not a TT kit you hear about regularly around the traps.

From day one i thought a stock engine wasn?t a good idea i.e did Holden deliver an engine that would deliver 300kw stock, with it in mind that some-one would double it...... and it still be OK???? So I went and got Sydney?s best (Sam) to build a tough iron block LS2 402. Not to chase heaps of power but to get a strong tough engine I wouldn?t have to worry about. Whilst the engine was being built, I ?upgraded? the turbos as they would not have the capacity for the larger engine.

Here is the problem simply put? my turbos sit down low next to the trans under the car. There is only so much room there so I couldn?t physically fit a larger bodied turbo (which the new 402 really deserves) ? so all the things we are playing around with now are because we are trying to get the original turbos (albeit internally bigger now) to do something there were never meant to do i.e. feed a big bastard 402!?.. the real solution is to throw everything out and start again ? but im not going to do that!

There is so much to tell in this, I would be writing a novel ? so if there is anything specific you would like to know, please feel free to ask!

[Delft Maloo]

if you write the novel ill be happy to read it.:yep:

[DaveHAT]

if you write the novel ill be happy to read it.:yep:

As would I Steve,:yep:

Following the thread with interest. Would this have been less of a problem with high mount turbo's as opposed to the low mounts?

I have no idea (some say in general :lol:) so I'm curious. :yep:

[choppo]

Would this have been less of a problem with high mount turbo's as opposed to the low mounts?

Not 100% sure actually - i know there is a hell of a lot more room up there and better accessibility! Hence why the top mount style, in the majority, is the option these days.
I forgot to mention the bit of experimentation bit..... as we know, my wastegates are too small for the bigger engine. Tried fitting the 44 Tial external wastegates but believe it or not it is an extraordinarily difficult thing to do ? this will be the expensive and final solution when all else has failed.
So, we decided to do a bit of experimentation by;
Rather than simply oversize the current round internal wastegate hole (look back at pic in post #19) from say 25mm dia up to say 36mm dia (with no guarantee that would be big enough), we decided to mill out the entire area surrounding the existing wastegate hole so it now follows the strange ?kidney shape? of the casting ? yes its all gone! Except a small edge all round so we can still seal against it. Now laser cut a thick piece of S.S. and connect it to the existing actuator creating a ?new kidney shaped flap??.. instant massive internal wastegate :bravo: !
Now the smarties here will note that when dealing with this strange shape, it wont open and close within the kidney shaped hole, if pivoting from the side as per standard ? so more mods required ? remove the existing pivot for the flap to another location so it now opens and closes within it?s own complex shape.
Gets better, as we cannot get a standard boost actuator for less than 8psi (which I want), one way of tricking the wastegate into a lower boost situation at low rpm is to crack the opening slightly but permanently - so from 1000rpm, the wastegate is leaking ? meaning the turbo won?t spool up so quick nor reach say 8psi so quick. For adjustability, we will install a turnbuckle in the actuator rod, to make future and subtle adjustments:yep:.

The above is possible because I have 8psi+ boost at anywhere over 2000rpm ? its way to high for so low in the revs. Normally we hear about ?lag? in turbo?d cars ? man I have the opposite problem hence the above strategy to leak boost low in the rpm range! I think it?s because I fundamentally have so much shear volume of exhaust gas coming out of a big cube engine ? its too much for the turbos (and I can?t make them bigger!)?. If you think back to cars typical of lag (usually 4/6cyl), they need every particle of exhaust gas just to spin the turbo up quickly ? in fact they cant get enough exhaust volume quick enough to get the thing spinning, therefore lag?.. so it makes my problem relatively rare in turbo world.

Ive rationalised this as follows;
Possible Pro?s ? increased wastegate size, simple(er) than other external option
Possible Con?s ? wont be able to control boost, exhaust will push the larger ?flap? open uncontrollably, flap will bend due to heat, basically the whole thing could turn to shite :puke: !

So this internal wastegate idea is a bit radical and may not work at all ? at least I can say we tried!

[Delft Maloo]

mate it all sounds great in theory and im the furthest from being an expert. i hope this idea is the sollution to what you need and all gets settled.
good luck and dont forget to show us pics of the operation.
cheers tim

[choppo]

mate it all sounds great in theory and im the furthest from being an expert. i hope this idea is the sollution to what you need and all gets settled.
good luck and dont forget to show us pics of the operation.
cheers tim
Yes,it will be interesting..... theory vs really working..... sounds good but will it work?
Any bets? :lmao:

[Delft Maloo]

it will work, just like my custom turbo manifold it will work but how well it works we will have to wait and see:yep: .
im really hoping you have succsess cause with the adjustability of the bleed valve for the wastegate it should let you taylor the the delivery of the turbo exactly how you like it.

[choppo]

Hmmmm... did someone say 400hp?

[choppo]

Hmmmm... did someone say 400hp?

Ok, ok.... no one took the bait. :( Did someone say 500rwhp?

[DaveHAT]

Ok, ok.... no one took the bait. :( Did someone say 500rwhp?

500rwhp ... :D

[choppo]

500rwhp ... :D

Thanks Tiger, was about to turn the PC off... but it goes higher.... :whip:

[DaveHAT]

Thanks Tiger, was about to turn the PC off... but it goes higher.... :whip:

C'mon Steve ... we get enough of this secret squirrel stuff from a couple of the founding members ... pony up some information fella :lol:

:waving:

[MrKeen]

625rwhp.........

[choppo]

625rwhp.........
Hang on hang on.... we have some inside info here:)

It gets even better, 620rwhp.... but at 9psi.

FYI - Each 1psi we played with was worth/showing anything between 40rwhp and 80rwhp

[MrKeen]

Hang on hang on.... we have some inside info here:)

It gets even better, 620rwhp.... but at 9psi.

FYI - Each 1psi we played with was worth/showing anything between 40rwhp and 80rwhp

Wow thats impressive, was 9psi your max run?I would have thought with the built motor you could be pulln 12psi at least?

[choppo]

Wow thats impressive, was 9psi your max run?I would have thought with the built motor you could be pulln 12psi at least?

Yep, can... dont want to. The 620 comes from a daily driven tune/engine - seriously, thats what im driving in the peak hour today .. a maximum power run with another 6 psi boost will produce heaps more if we want. If we wanted to show big figures, we could - but one tip - keep the boost as low as you can on the best fuel you can... Ive been shot down before on this, but run 12 - 15 - 18psi for a while on pump fuel..:waving:

[MrKeen]

Yep, can... dont want to. The 620 comes from a daily driven tune/engine - seriously, thats what im driving in the peak hour today .. a maximum power run with another 6 psi boost will produce heaps more if we want. If we wanted to show big figures, we could - but one tip - keep the boost as low as you can on the best fuel you can... Ive been shot down before on this, but run 12 - 15 - 18psi for a while on pump fuel..:waving:

Your being soft...620 hp daily driver , is that all.Where is the nos?

Impressive NOT.:whip: :)

[MrKeen]

It sounds like your getting some of issues you've been haveing sorted.Good stuff.

[BOMI]

Thats great man :yep:

Congrats :cheers: :thumbs:


Troy :)

[choppo]

It sounds like your getting some of issues you've been haveing sorted.Good stuff.

Nah, still working them out with my psychiatrist :bravo:

[Delft Maloo]

great work choppo, im still a long way from finishing and im just as excited for you as i get when work on mine. did you end up modding the wastegates like disscussed and are they working as you hoped.Picies if you can please.

[Delft Maloo]

how about an update choppo, im keen to find out more.

[MID02K]

Ive only just read this thread..
1. Informative
2. Impressive
3. Jealous :(

[35R]

Ive only just read this thread..
1. Informative
2. Impressive
3. Jealous :(

Ditto Ditto Ditto!

awesome stuff, massive power

[choppo]

Going strong as ever! Arguably too much power :shock: but heaps of fun. Ive changed tact though... after doing the Dutton, im building a circuit car where believe it or not, more power aint always good:(
Keeping the ute as it, getting another sedan...
BTW, im having heaps of trouble with the Diff Tech super tough axles...

[seldo]

. Ive changed tact though...
Umm....Don't take this as a personal affront, but I'd like to help you advance your personal communication skills.... "tact" is "skill in personal communication with consideration for others' feelings". What you really meant to say was "I've changed ""tack" which is a sailing term to indicate a change of direction to maximise the benefit from the wind direction". So we understand the subtleties of the English language, it is, I hope , beneficial to have these seemingly trivialities pointed out to us. Please don't feel this is a personal attack - it's not, but I do hope you understand the difference between what you said, and what you intended... :) :cheers:

[seedyrom]

YEH!! Wot 'e sed!

[choppo]

Umm....Don't take this as a personal affront, but I'd like to help you advance your personal communication skills.... "tact" is "skill in personal communication with consideration for others' feelings". What you really meant to say was "I've changed ""tack" which is a sailing term to indicate a change of direction to maximise the benefit from the wind direction". So we understand the subtleties of the English language, it is, I hope , beneficial to have these seemingly trivialities pointed out to us. Please don't feel this is a personal attack - it's not, but I do hope you understand the difference between what you said, and what you intended... :) :cheers:

Sorry sir, i do apologise - after ten stubbies on a Friday evening im not really interested in the finer points of the English language - i have to be anal like that all week - i will continue to exercise my wright to speell wreally shit whilst on da furom(s) :moon:

[seldo]

Sorry sir, i do apologise - after ten stubbies on a Friday evening im not really interested in the finer points of the English language - i have to be anal like that all week - i will continue to exercise my wright to speell wreally shit whilst on da furom(s) :moon:

:lol: Apology accepted - Only 10?....Just don't do it again or I'll really put shit on youse...oops...:eyes: ;)

[NickS]

Umm....Don't take this as a personal affront, but I'd like to help you advance your personal communication skills.... "tact" is "skill in personal communication with consideration for others' feelings". What you really meant to say was "I've changed ""tack" which is a sailing term to indicate a change of direction to maximise the benefit from the wind direction". So we understand the subtleties of the English language, it is, I hope , beneficial to have these seemingly trivialities pointed out to us. Please don't feel this is a personal attack - it's not, but I do hope you understand the difference between what you said, and what you intended... :) :cheers:

Don't ever change seldo ... :bravo:

Good to hear you're having fun Steve ... will you want the RE55s for Wakefield next week ??? Might need all the grip you can get by the sounds of things.

:yep:

[choppo]

Don't ever change seldo ... :bravo:

Good to hear you're having fun Steve ... will you want the RE55s for Wakefield next week ??? Might need all the grip you can get by the sounds of things.

:yep:

Ill start another thread i think... just bought a stock VY SV8 witch (that's for Seldo:bravo: ) i get the Friday b4 we go to the track...

[Jonesy]

Going strong as ever! Arguably too much power :shock: but heaps of fun. Ive changed tact though... after doing the Dutton, im building a circuit car where believe it or not, more power aint always good:(
Keeping the ute as it, getting another sedan...
BTW, im having heaps of trouble with the Diff Tech super tough axles...


Whats the problems that you've been having with your axles?

[choppo]

Whats the problems that you've been having with your axles?

Not 100% sure as yet - i have to remove them and give them back so they can do some fault finding.. been too busy to do this but hopefully this week.
The problem is at anywhere near 'normal height' and definetly at any lowered height, when i accelerate i get an awful grinding noise. The lower i drop the car and/or harder i accelerate, the worse it gets. My guess is the angle of the axle to CV joint is too severe when at any 'low' height OR a simple manufacturing fault.... as mentioned 1st step is to remove them and let DT have a look and see what the prob is.
The pisser is i have to drive with the rear end up in the air so i dont damage them... looks gay!:puke:

[Jonesy]

well if the axles are standard length thats going to be your problem. The axles are going to be too long for when the car is lowered. The axle has a fixed inner cv and a floating outer so that when the suspention goes through its travel the axle can move within the cv.
Once you lower the car it moves the axles too far into the cv and then starts hitting the cv cage. I would guess you'll need to cut maybe 5mm off the end and your problems will be gone.
I'm no drive-line expert, my mates old man is an i've picked up enough info about drive-lines over the years that it susprises me sometimes.

Dave

[choppo]

well if the axles are standard length thats going to be your problem. The axles are going to be too long for when the car is lowered. The axle has a fixed inner cv and a floating outer so that when the suspention goes through its travel the axle can move within the cv.
Once you lower the car it moves the axles too far into the cv and then starts hitting the cv cage. I would guess you'll need to cut maybe 5mm off the end and your problems will be gone.
I'm no drive-line expert, my mates old man is an i've picked up enough info about drive-lines over the years that it susprises me sometimes.

Dave

One step ahead of you..... these are 'double plunging' axles so the thing you explain there is not an issue i.e. std axle only moves @ one end and the length binds them - these float at both ends:yep: which means the length issue goes away. Plus, we double checked this and the end float is heaps, even when i have it slammed on the ground.
It has something to do with the angle the shaft is meeting the CV joint - particularly the outboard side where we calculated it would bind at around 19deg on the bench. In the car we can only achieve 12-14deg..... but obviously the angle of bind on the bench must be slightly different to that in its actual working position.
As an aside, the height at which it is a problem, is no where near being what you consider 'lowered'... as mentioned, it would be higher than stock to eliminate the noise at the moment.

[Jonesy]

sounds like a strange problem then, hope you work out the problem.