Aggressive tune

[lautray]

We are preparing a specific tune just for the drags. Should we just have as much timing as the engine will take, just short of knock, or is there an "optimum" figure that would produce better et's? At the business end of the main spark table, we have ~28*, with nil kr. Have not tried adding more timing just yet.

Any other tips people are willing to share/divulge?

[BOMI]

I think ATM that 28 DEG is getting towards the more dangerous end of your tune. I say this after having many conversations with many people about timing and tunning.

I am by no means well versed in Tuning but I think that if it gets hot on the day and you are running that much things mights start to rattle.

Im intersested to hear what Luke and Sonny have to say on this one :)

My two cents, good luck to Maroubra Tunning :thumbs:

Troy :)

[CarlFST60L]

I have seen a tune run great 12.5@ 110mph with only 18Degrees of timing, i guess there is more to this than just timing? i think i remeber hearing 11.5AFR's with the most timing you can get is best?

PS I have NFI! :confused:

[RedVYIISS]

we have ~28*, with nil kr.

nil kr = nil knock retard?

(I'm glad its not my engine if that's the case)

[RedVYIISS]

do you remember this.....

(I joked about Sonny listening to the races while he was tuning my car)

http://i39.photobucket.com/albums/e169/RedVYIISS/DSCF0654.jpg

might be worth investing in a set.

I was in the car when Sonny tuned it. I had the laptop sitting on my lap and was watching for knock on the screen (and of course listening...... though I must admit I'm as deaf as a post).

Sonny was off the throttle before I saw any knock on the trace. Needless to say, I didn't hear anything either.

[lautray]

I think ATM that 28 DEG is getting towards the more dangerous end of your tune. I say this after having many conversations with many people about timing and tunning.

I am by no means well versed in Tuning but I think that if it gets hot on the day and you are running that much things mights start to rattle.

Im intersested to hear what Luke and Sonny have to say on this one :)

My two cents, good luck to Maroubra Tunning :thumbs:

Troy :)
Dangerous is an interesting choice of words, Troy. No, the car does not knock when IAT is high as there are correction tables to compensate for this in the tune :) . Apparently my car doesn't mind the timing wound up a little ;). When the car was bolt-on with Dick's tune, it ran peak timing ~29*... nil kr issues & was good for 11.9's :D. I guess each car is different. I have heard some people (tuners & pretenders) say you want peak timing, whereas others say peak is not necessarily required for optimum performance. Interesting how each goes their own way to try & achieve same result.

We expect to try a few different things when on the dyno :up2sum: . Will report back with results. Not exactly mythbusting, more learning & a bit of fact-finding along the way.

[35R]

I have looked at probably over 100 LS1 tunes (as posted in the tune libraries and those shared over the last 12 months) and 23~27* is where most of the NA tunes are at. 29* is pushing the boundaries I reckon - i've never seen higher..

Most of the tuning guides I have seen, well they essentially suggest pushing it until you see KR, then bring it back a little. However this (http://www.efi101.com/forum/viewtopic.php?t=7) post has some interesting comments which fly in the face of that methodology

[BigKahuna]

Winding in as much timint as it will take doesnt always produce the best power of more importantly torque.

Have a read thru this thread. Givn the contributors, Id be inclined to take notice too.
http://forum.efilive.com/showthread.php?t=4157&highlight=timing

[veewhytu]

Im no tuner, but why not push as much timing in as you can before knock becomes an issue? , if it's not producing the desired results pull it back a little on the day.

My ute takes up to 30* @ wot...dangerous...absolutely not, not even close to the edge.
My instructions to my tuner at the time were "Its'a daily driven work horse, i need to be able to flog it up a hill on a 40 degree day with 600kgs of concrete in the back without any problems" , logging has shown that he got it exactly as i asked :bow:

[BigKahuna]

Im no tuner, but why not push as much timing in as you can before knock becomes an issue? , if it's not producing the desired results pull it back a little on the day.
Because there is often no need to run max timing. Max timing doesnt necessarily mean max power or torque.
Read the link in my post above.

[veewhytu]

Because there is often no need to run max timing. Max timing doesnt necessarily mean max power or torque.
Read the link in my post above.

Agreed it is beneficial to run less than max timing just before and at peak cylinder pressure, but maybe it's helpful to do so elsewhere?

We've got very similar setups btw, is yours manual though?

Edit: sorry just checked, yep its manual.

[veewhytu]

oops...double post.

[35R]

I have too read a lot to suggest that max timing isnt necessarily best, it kind of made sense (peak cylinder pressure theory etc).

Erik and I spent all day on a dyno today with a couple of ls1's, thanks to Dale at Castle Hill Exhaust (more to follow on that in another thread).. so after trying some different timing i would now hazard a guess that LS1's respond to near maximum timing very well.

Of course every engine is different, but as a rule with NA LSx i would go with max timing (or perhaps within ~2* range anyway). We did have an instance where we pulled out 1 or 2* and it made a bit more HP. But certainly not anything like say 22* vs 28*.

Interesting stuff.

An interetsing chart would be an XY scatter plot; with peak power on one axis, and WOT timing on the other, for the top 100 bolt-on cars (granted impossible). Anyway I am guessing you will see 26*+ for most of them.

[RedVYIISS]

Erik and I spent all day on a dyno today with a couple of ls1's, thanks to Dale at Castle Hill Exhaust (more to follow on that in another thread)..

Good stuff, now that's the way to do it (research), though I expect Dale was able to give you a lot of the answers before the cars went on the dyno (simply because of the number of LS1/2's he's tuned and time spent on the dyno). I suspect a good learning curve was had yesterday.

[35R]

Good stuff, now that's the way to do it (research), though I expect Dale was able to give you a lot of the answers before the cars went on the dyno (simply because of the number of LS1/2's he's tuned and time spent on the dyno). I suspect a good learning curve was had yesterday.

It was definitely one of things high on our list (to try some different timing) and thanks to Dale @ CHE we were able to try ~ at least on our cars anyway. Obviously there is a lot more to a tidy tune than max timing, I think we spent all of about 5 minutes on timing in the end, versus several hours on the dyno altogether. We got some great exposure real time tuning using HPTuners; I can see how real time is a god-send for those with a dyno.

[SSUte01]

I have to say my piddly experience has shown exactly the same that LS1s tend to respond best to close to max possible safe timing. Mine for example made best power at 28.5* but will still handle a little more albeit for no gains. I have a curve for WOT timing and I simply adjust the 'size' of it to suit the application - works for me.

Generally I find the best approach, and I would like to hear from someone who has far more experience than my dabblings, is to use a reasonable timing curve (close to where you anticipate you'll end up) and start on the rich side of fuelling (based on calculated airflow be it MAF or SD) get the fuelling spot on and then start to incrementally add timing until no more gain is achieved - double check fuelling with new timing as they are obviously inter-related and repeat as necessary. This is pretty easy for WOT as it is easy isolate it is the rest of the tune that takes so long ;)

It does seem that within 1-2* of max timing produces the best results though.

[BigKahuna]

Just to clarify, we are referring to bolt on cars with stock camshafts here arent we.
I have around 28* with my baby 222/224 cam.
Larger cams like more timing.

[SSUte01]

Just to clarify, we are referring to bolt on cars with stock camshafts here arent we.
I have around 28* with my baby 222/224 cam.
Larger cams like more timing.

Dont think so.... Didn't think we were discriminating - sorry I just assumed that those subscribed knew about each others cams, apologies, mine is a 218/224 didn't wanna mislead anyone. Bolt-on cars vary quite a bit for me depending on fuel and mods. Some for me made best 21-22* and others 24.5* guess its a matter of finding that out. All cars mentioned apart from Erik when he was referring to std cam now have a cam.

A side note, I notice you called yours a 'baby' cam, what constitutes a mild or big cam in your opinion. I have always been interested on what is big for some people - I am not being critical either just purely interested in opinions on what people are happy to consider baby, mild and big. For a street car I feel mine is 'mild'

Agreed larger than stock cams 'usually' perform best with more timing.

How do you find that profile - I have never heard anyone have anything but praise for it.

Not to hijack the thread but on the topic of drag tunes, street tunes etc, do most people have a specific tune for application or like myself race it that same way you drove it to the track. Just curious as to why people have different tune for the drags - optimised for better fuel??

[lautray]

Not to hijack the thread but on the topic of drag tunes, street tunes etc, do most people have a specific tune for application or like myself race it that same way you drove it to the track. Just curious as to why people have different tune for the drags - optimised for better fuel??
Luke, I know of one person that has specific drag tune... allows for a little more timing for use with Pro-Strength Octane Booster, or so I was told. It has run very, very respectable numbers & good luck to him & the workshop behind him. They did the hard yards & got the results to match :).

After our dyno tuning exercise last Saturday (Cheers Dale :bow: ), I don't think we'll need a specific tune ;) . The numbers achieved suggest that it should go ok, driver depending. SOTP feel (which is even more important) is fantastic :D.

[DaveHAT]

A side note, I notice you called yours a 'baby' cam, what constitutes a mild or big cam in your opinion. I have always been interested on what is big for some people - I am not being critical either just purely interested in opinions on what people are happy to consider baby, mild and big. For a street car I feel mine is 'mild'


Question wasn't directed to me but I have 2 cents lying around today and IMHO any CAM nudging the 228-230 arena is getting a bit beyond "baby" categorisation unless you're comparing to something like Markone2's 240 plus CAM and Darren Parks 260-ish (I think it is) CAM in his Clubsport which I suppose would I land a 228 duration CAM in "baby" land.

The time old question isn't it ... how long is a piece of string? :confused:

IMHO:
Baby = GTS spec & similar style 212 - 218 and similar durations
Mild = 220-230 durations
Big = 230 - 240 and slightly above
Anything above mid 240 ish CAM .... devise your own term for it I suppose.

To reiterate, this is just my opinion on CAM sizings and not a shot at anyone elses ideas on the subject and as we all know, opinions are like aresholes ... everyone has one. :werd:

[DaveHAT]

A side note, I notice you called yours a 'baby' cam, what constitutes a mild or big cam in your opinion. I have always been interested on what is big for some people - I am not being critical either just purely interested in opinions on what people are happy to consider baby, mild and big. For a street car I feel mine is 'mild'


Question wasn't directed to me but I have 2 cents lying around today and IMHO any CAM nudging the 228-230 arena is getting a bit beyond "baby" categorisation unless you're comparing to something like Markone2's 240 plus CAM and Darren Parks 260-ish (I think it is) CAM in his Clubsport which I suppose would I land a 228 duration CAM in "baby" land.

The time old question isn't it ... how long is a piece of string? :confused:

IMHO:
Baby = GTS spec & similar style 212 - 218 and similar durations
Mild = 220-230 durations
Big = 230 - 240 and slightly above
Anything above mid 240 ish CAM .... devise your own term for it I suppose.

To reiterate, this is just my opinion on CAM sizings and not a shot at anyone elses ideas on the subject and as we all know, opinions are like aresholes ... everyone has one. :werd:

[BOMI]

Just to clarify, we are referring to bolt on cars with stock camshafts here arent we.
I have around 28* with my baby 222/224 cam.
Larger cams like more timing.


BK you have opened a Cam of worms here :lmao:

I say in my opinion that baby is like what I have, around 214/218 or the like.

Mild would be 222/224 and above that I would call Big!!


Troy :)

[35R]

I've got a fetus cam

[RedVYIISS]

and mine's just a twinkle in me dads eye....

[BOMI]

Well ah um ah well well mines a Atom cam, nee nerrrr nee nerrrr :lmao:


Sorry Mitta E, back on topic with your thread :hide:


Troy :)

[Sonny@AutoWerks]

An engine is a air pump,thats all it is,the amount of timing an engine will take will change from engine to engine,also change from cam to cam,theres no timing number specific,eg i made 330rwkw with 19deg timing,27deg timing doesnt mean ur gonna make power,it all depends on ur setup,some cars love high timing,perfect example is eriks and daves car,then again theres others where you put anymore then 23deg they ping.

The cam plays a big part on how much timing the engine will take depending on cylinder pressure,as dale knows the way i set my cams up you can throw 27deg in no worries and it wont ping.At the same time theres no such thing that it wont ping,you get a stinking hot day 108deg coolant temp 70deg intake temp,now thats a brew for detonation unless you build in safety into ur tune to retard to 0 degs timing,if you do this,theres a downfall,the engine lacks power to as much as the timing retards,i recently logged a car which was down on power and had been back to the dealer many occasions and they couldnt fault it.

What i noticed was as the wheather got hotter the timing retarded to 4deg,the logger was showing detonation,but i couldnt hear it,so i put my headpones on and hooked up the stethascope and had a listen,in actual fact the vehicle wasnt pinging at all,it was a faulty knock sensor,in needless to say when a engine is cammed,the knock sensors dont work properly,so ppl who tune their safety into the knock sensors can become a hazard as GM tune the knock sensors to std ls1 engine harmonics,once the engine is cammed the knock sensors are no longer in std harmonics as they will pick up knock wen there isnt cause of excess valve train harmonics from the rockers,This is a point to keep in mind when tuning cammed cars,the stethascope is a good tool in this case.

regards sonny

[lautray]

Good post Sonny.

[BigKahuna]

Thanks Sonny.
Geez I was at the Docs yesty. I shoulda slipped her stethoscope into my pocket before I left.

[BOMI]

Good post there Sonny.

I have heard of the Stethascope being used, also I have seen a 30cm length of broom handle. Placed onto certain parts of the engine it transfers the noise straight up to your ear.

Looks funny, but at the same time it works well.


Troy :)

[BLK 1T]

Bomi
Done the same with a long screwdriver - handle end jammed tight to one ear.
Dont recommend the other way round
Phil

[Ron]

That warning may have come a bit too late for a few blokes around here Phil:stick:

[oztrack]

My car was the same as yours on the dyno. It liked timing and suggested a need for more octane to give more power. Maybe having 10.7:1 does that.

I have 28.5 degrees maximum at WOT.

[Sonny@AutoWerks]

My car was the same as yours on the dyno. It liked timing and suggested a need for more octane to give more power. Maybe having 10.7:1 does that.

I have 28.5 degrees maximum at WOT.


Your forgetting about the cam and the 1.8 rockers which change the duration of the cam hence bleeding of compression,hence you wont actually have 10.7:1 till peak cylinder pressure round 4500rpm.

[oztrack]

Hi Sonny

Erik has a cam now - so i was referring to that.

No chance i would try my cars timing curve in a stock cammed ls1.

But i have spent a fair bit of time on a dyno searching for a tune with less timing that leaner. But it didnt like it at all and neither did the same strategy at the track.

[lautray]

Your forgetting about the cam and the 1.8 rockers which change the duration of the cam hence bleeding of compression,hence you wont actually have 10.7:1 till peak cylinder pressure round 4500rpm.
Would 1.8 rockers move Steve's "baby" cam out of the "baby" category???

[oztrack]

The overall effect is 218 222 at 050. with 555 and 563 lift. The valve events are still the same but the valve ramp rate is higher. I reckon a baby is anything up to and including the 222 224.

It would be interesting to be able to rank all of the common cams in terms of overlap. All of the cams i have tuned (up to 238 240) have behaved very well other than at idle. Its easy to go too big (beyond a baby) and struggle with the stock stall converter to maintain driveability.

[lautray]

I have 28.5 degrees maximum at WOT.
Steve, mine running much, much more than 28* ;). I guess heads will bring that down though???

[Sonny@AutoWerks]

Would 1.8 rockers move Steve's "baby" cam out of the "baby" category???

It will still be a small cam,though have the benifits.

[oztrack]

Yes the heads probably brought mine down around 2 degrees. But a good cold air intake, 160 thermo and free flowing exhast make it less inclined to knock. The big area that timing needs reducing is 0.40g/cylinder to 0.60g/cylinder at between 1600rpm and 2000rpm.

Factor in the need for a bigger manifold and TB with the heads. My latest mod would have gained 20+ rwkw over the stock TB and LS6 manifold.

[JohnL]

Thanks for being open with your tune details Steve. Do you care to say just how much timing you're got in those high cylinder load/ 1600 to 2000 rpm areas?

It's good to be reminded that there's 3 times as much time to get detonation happening at 2000 rpm than at 6000 rpm.

John

[oztrack]

Close to full load timing and airflow

1600rpm 22.0 degrees 0.60g/cylinder
1800rpm 23.0/ 0.68
2000rpm 24.0/ 0.68
2400rpm 24.0/0.72
2800rpm 24.5/0.80

This is just from some recent logs - taken in 20-30 deg IAT.
Peak g/cylinderhas been 0.99/20deg C IAT and at around 5600rpm.

[BigKahuna]

Thanks for being open with your tune details Steve. Do you care to say just how much timing you're got in those high cylinder load/ 1600 to 2000 rpm areas?

It's good to be reminded that there's 3 times as much time to get detonation happening at 2000 rpm than at 6000 rpm.

John

1200 rpm 24.411621 22.016602 19.995117 17.995606 18.017578 17.006836

1400 rpm 25.905762 23.994141 21.994629 21.005859 19.511719 17.995606

1600 rpm 29.003906 26.499023 24.213867 22.390137 22.016602 20.720215

thats from 0.40g/cyl to 0.60 g/cyl.

222/224 Comp cam.

[VYss Kiwi]

Seems to me that the fresher the Gas and the Higher the Octane you can get a bit more timing out of her.Have also found that if a car is driven hardish from new it will overall perform better and allways want to go,and not like puttering around.This is only my thoughts and i maybe completly wrong.cheers.i just like going fast as long as im in control.

[OLS108]

Great thread...

Cheers

Dave