[Fraxum]

I have ordered an LT2 Camaro IM modded kit for my LT1.

I was thinking of running this without a tune. Now I am not that worried about tuning, but in light of the current LT1 motor valve issues and the old starter stuff, I am a little worried if I will need my drive train warranty.

But mainly my decision is based on whether or not Atco is sold and becomes something else.

So I want to hold off on tuning for now. After reading the threads it is still not clear to me.

I have been warned recently by somone who seems to be in the know that before I install the LT2 IM I need to do my research. The warning was the LT2 IM installed with the stock TB would run too lean at high rpm. I am happy with the stock redline, even if I tune for more secure motor longevity. But is the lean condition enough to damage the motor? I also occasionally hit the rev limiter. :(

I have to laugh at myself for saying all that as I run my LT1 as hard as it can usually once a week. AND I want to keep this car for my forever.

And I know what some are thinking, "Don't dance if you can't pay the band." I agree.

I have one on order. I am a bit peeved they took my Paypal $$ with no delivery date to ship. But I might as well buy it anyway, it will be easy to sell if I do not use it.

[s346k]

ya know, i put the LT2 intake manifold on my bolt on/e85 car that was already lean. ran the shit out of it and nothing happened. granted it was on ethanol..

[OB0001]

Originally Posted by Fraxum

I have ordered an LT2 Camaro IM modded kit for my LT1.

I was thinking of running this without a tune. Now I am not that worried about tuning, but in light of the current LT1 motor valve issues and the old starter stuff, I am a little worried if I will need my drive train warranty.

But mainly my decision is based on whether or not Atco is sold and becomes something else.

So I want to hold off on tuning for now. After reading the threads it is still not clear to me.

I have been warned recently by somone who seems to be in the know that before I install the LT2 IM I need to do my research. The warning was the LT2 IM installed with the stock TB would run too lean at high rpm. I am happy with the stock redline, even if I tune for more secure motor longevity. But is the lean condition enough to damage the motor? I also occasionally hit the rev limiter. :(

I have to laugh at myself for saying all that as I run my LT1 as hard as it can usually once a week. AND I want to keep this car for my forever.

And I know what some are thinking, "Don't dance if you can't pay the band." I agree.

I have one on order. I am a bit peeved they took my Paypal $$ with no delivery date to ship. But I might as well buy it anyway, it will be easy to sell if I do not use it.

Who did you purchase IM from? I purchased from GPI/ non ported, 9/11, on 9/23 they said they received the IM and they working on it, still working on the IM as of 9/26.

[appleman22]

it NEEDS a tune. It runs lean up top. The numbers don't lie.

[laynlo15]

I would think that also. More air, different runner lengths and its just gonna run better and safer.

[Fraxum]

Originally Posted by OB0001

Who did you purchase IM from? I purchased from GPI/ non ported, 9/11, on 9/23 they said they received the IM and they working on it, still working on the IM as of 9/26.

Me too GPI. I ordered it about a week ago. I have heard nothing. But I did once find a work queue. There were at least 10 ahead of me.

[Fraxum]

Originally Posted by laynlo15

I would think that also. More air, different runner lengths and its just gonna run better and safer.

Agreed I would think it would run better for sure. I was wondering the risk of destroying the motor. I also read several opinions that differ. Is it some risk or would I be an idiot to do this? I have been an idiot before building a M6 Twin Turbo.

I know the tuners are all over this. But mostly they keep most of what they know close to the vest. I don't blame them.

[Fraxum]

Originally Posted by appleman22

it NEEDS a tune. It runs lean up top. The numbers don't lie.

I am not disagreeing with you. Where are those numbers? Have they been posted? I could not find that. Once I find those I will look into what they mean so I can learn something as well.

I think that a ported stock LT1 IM does not need a tune. But the LT2 IM is a different beast. Anybody have a stock ported IM they want to sell?

I'd probably try that first to get my M6 LT1 into the 11s.

[cmitchell17]

I have to disagree with everyone, the MAF sensor will pick up the additional airflow at higher rpms, especially since the ECM ignores everything except the MAF sensor above 4000 rpms.

[Chemist]

I ordered the LT2 from GPI on 8/21 and received it yesterday. Don't worry about them, you will receive it

[s346k]

what i've seen is guys claiming a previous 12.8 car was showing 13.2, somewhere in that ballpark. a stock tune car runs what, 12.5? even if it then goes to 13.0 - that's not lean enough to hurt anything. i think it would knock on gasoline, stock tune, negating the benefits on an otherwise stock setup. my car knocked often when it was bone stock unless the weather was perfect.

[Fraxum]

Originally Posted by Chemist

I ordered the LT2 from GPI on 8/21 and received it yesterday. Don't worry about them, you will receive it

Thanks. I was not worried. But maybe they did it that way because of the labor involved. They have a good rep.

[Fraxum]

Originally Posted by s346k

what i've seen is guys claiming a previous 12.8 car was showing 13.2, somewhere in that ballpark. a stock tune car runs what, 12.5? even if it then goes to 13.0 - that's not lean enough to hurt anything. i think it would knock on gasoline, stock tune, negating the benefits on an otherwise stock setup. my car knocked often when it was bone stock unless the weather was perfect.

Thanks, what is that number, gas/oxygen ratio or some thing like that? We are taliking about AFR?

I also found this:

"For example, for a gasoline engine, an AFR of 16.5:1 is lean and 13.7:1 is rich."


And the optimal AFR:

"The stoichiometric mixture for a gasoline engine is the ideal ratio of air to fuel that burns all fuel with no excess air. For gasoline fuel, the stoichiometric air–fuel mixture is about 14.7:1 i.e. for every one gram of fuel, 14.7 grams of air are required."

So in tuning the tuner tries to get to the stoichiometric mixture throughout the rev range? Or do they cheat a little by going slightly lean with a little more timing? Just guessing.

Wouldn't the knock cause the software controlled timing to pull back with the stock tune protecting the motor and negating the benefit somewhat of the LT2 IM? Tuners would smooth out the AFR to get the full benfit of the IM.

I only run 93.

So I have a new HP tuner brick to log my runs if I put the LT2 IM on. Then I can probably find someone who can help me figure out what is happening when I run all out.

Appleman22, thanks for the heads up. Sound like a plan?

ThE LT2 IM should get me into the 11s. I also added the VT Scoop and a Rotofab dry. With the DRs and RF I am at 12.10.. in +200 air. Seats in.

[cmitchell17]

Originally Posted by Fraxum

Thanks, what is that number, gas/oxygen ratio or some thing like that? We are taliking about AFR?

I also found this:

"For example, for a gasoline engine, an AFR of 16.5:1 is lean and 13.7:1 is rich."


And the optimal AFR:

"The stoichiometric mixture for a gasoline engine is the ideal ratio of air to fuel that burns all fuel with no excess air. For gasoline fuel, the stoichiometric air–fuel mixture is about 14.7:1 i.e. for every one gram of fuel, 14.7 grams of air are required."

So in tuning the tuner tries to get to the stoichiometric mixture throughout the rev range? Or do they cheat a little by going slightly lean with a little more timing? Just guessing.

Wouldn't the knock cause the software controlled timing to pull back with the stock tune protecting the motor and negating the benefit somewhat of the LT2 IM? Tuners would smooth out the AFR to get the full benfit of the IM.

I only run 93.

So I have a new HP tuner brick to log my runs if I put the LT2 IM on. Then I can probably find someone who can help me figure out what is happening when I run all out.

Appleman22, thanks for the heads up. Sound like a plan?

ThE LT2 IM should get me into the 11s. I also added the VT Scoop and a Rotofab dry. With the DRs and RF I am at 12.10.. in +200 air. Seats in.

The engine will run fine and normally at a stoichiometric ~14.1:1 air fuel ratio at WOT. Enrichment is done at high throttle and WOT because of the extra cooling offered by the extra fuel, and to make more power than could be made at stoich ratio.

By running slightly richer (up to a point) you will give it a little extra fuel to ensure that all the available oxygen is "used up" or burned. Perfect combustion (or in chemistry terms a completed reaction) is always pursed but usually never reached (eventually it is reached in the cat converter).