2.3L, 10:1 CR Tuning Advice Needed

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Jun 2, 2014 | 05:19 AM

#31

wreckleford

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From: Jamaica

Quote:

Originally Posted by TurboTylerIX

From what I have learned you want to get the ignition timing to whatever it needs to be in order to produce maximum cylinder pressure at 15 to 20 degrees after TDC because that is what studies have shown to produce the most power.

The burn speed determines how fast that maximum cylinder pressure is developed and the burn speed is affected by your AFR. Around 12.5 afr for gasoline burns fastest, as you go leaner or richer from there is gets slower.

I have seen the big power guys running negative timing values like this...
https://www.evolutionm.net/forums/ec...ne-800whp.html

I'm not saying that I need to be running negative timing in my current application, I am just being timid and trying to stay safe on e85 since I just dropped so much coin on this 2.3L build and I haven't tuned on E85 before. I'll probably try for 1* max at peak load until I can get on a real dyno and can be more confident in finding mbt.

Yes, I understand about cylinder pressures, so if you want to put it another way, would cylinder pressures not be higher with lower boost and higher timing versus higher boost and lower (negative) timing. This is a general question and it may depend on setup.

I have asked Aaron about his timing numbers before. The engine should require least timing at peak torque but if you look at the dyno sheet you will see the timing at peak torque does not have the lowest timing numbers. He said the reason he did it was for traction control.

Jun 6, 2014 | 09:35 PM

#32

TurboTylerIX

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From: The Colony, TX

Here is an update of where I stand currently. I am pretty happy with it. I was getting phantom knock probably from my built 2.3 with removed balance shafts and hard front motor mount. I had to change the stock knock tables just a bit.

I am not sure if I can get much more out of the stock turbo?

A BIG thank you to Razorlab for offering some help.

Jun 7, 2014 | 01:27 AM

#33

foxbat

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From: UAE

Nice results!
Was 0* -1* the best timing possible at peak boost? Did you get to check for boost leaks?

Last edited by foxbat; Jun 7, 2014 at 02:32 AM.

Jun 7, 2014 | 07:06 AM

#34

TurboTylerIX

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From: The Colony, TX

Quote:

Originally Posted by foxbat

Nice results!
Was 0* -1* the best timing possible at peak boost? Did you get to check for boost leaks?

Thanks.

Yes I did find one vacuum hose had blown off, but i know it wasn't that way for more than a week. It didn't really have much affect on my load values but it did change my AFR's a couple points.

I'll probably try to bump the peak to 1*.. I'm not sure why sometimes I get -1* where my map has 0* at peak and i have 0 knock. But besides that, I think I'll leave it as is until I get on a real dyno. I might be able to push it another degree or two throughout, but I don't think I want to rely on VD for that.

Jun 7, 2014 | 07:19 AM

#35

wreckleford

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From: Jamaica

Quote:

Originally Posted by TurboTylerIX

Thanks.

The intake air temp compensation is likely causing the difference between the map and actual timing numbers.

Jun 7, 2014 | 07:21 AM

#36

TurboTylerIX

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From: The Colony, TX

Quote:

Originally Posted by wreckleford

The intake air temp compensation is likely causing the difference between the map and actual timing numbers.

Ah, oh ya. I should have known that...kinda had a feeling it might be something like that. Makes sense why the butt dyno tells me my car is much faster in the cool mornings and evenings.