Need help with first attempt.
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Joined: Apr 2001
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From: Fresno, Ca
Need help with first attempt.
I'm getting ready for my first attempt at a prom for my 408. I should be finished with my 7730 conversion this weekend and naturally, I have a few questions. I'm starting with ANHT code and going from there. I pretty much know where the constants should be, but I'm concerned about running the VE tables *way* too lean on my first try. One of the brilliant minds here recently posted that the stock tables ran about %20 richer than needed. Will this be enough to buffer me from a potentially damaging lean condition? I know it will take me a zillion tries to get the VE tables right, but initially I'm just concerned about causing serious damage to a motor I have *way* too much invested in to damage with ignorance.
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408cid 1985 Corvette
http://www.mojosgarage.com
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408cid 1985 Corvette
http://www.mojosgarage.com
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Joined: Jul 1999
Posts: 10,907
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From: The Bone Yard
Car: Death Mobile
Engine: 666 c.i.
Make sure you have your Cylinder Volume set up to account for the big motor, and set your Injector Flow Constant lower than your actual injectors to ensure that you are AT LEAST running a tad rich.
Play with the Injector Flow Constant a bit to get it "in the ball park" and then fine tune the VE tables from there.
This is just one method to start with a "totally unknown" like your setup.
BTW, do you have an oil temperature sensor for the ECM? If not, the ANHT will throw a code. In that case, you may wish to try using the AUJP (F-body L98) Bin. It is the same as the Vette Bin, but without the Oil Temperature sensor.
Play with the Injector Flow Constant a bit to get it "in the ball park" and then fine tune the VE tables from there.
This is just one method to start with a "totally unknown" like your setup.
BTW, do you have an oil temperature sensor for the ECM? If not, the ANHT will throw a code. In that case, you may wish to try using the AUJP (F-body L98) Bin. It is the same as the Vette Bin, but without the Oil Temperature sensor.
Thread Starter
Member
Joined: Apr 2001
Posts: 138
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From: Fresno, Ca
Thanks Glenn!
I do have an oil pressure sensor, as it is a Vette... One last question: I am using Ford Motorsport 30# injectors, which are rated at a lower FP rating than the GM units. Do you think that would be enough of a discrepancy to start with 30# in the constants? As a note, my 870 prom is using a rating higher than 30#, but since I don't have the TDF for the 870, I'm not sure what the exact number is.
Chris
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408cid 1985 Corvette
http://www.mojosgarage.com
I do have an oil pressure sensor, as it is a Vette... One last question: I am using Ford Motorsport 30# injectors, which are rated at a lower FP rating than the GM units. Do you think that would be enough of a discrepancy to start with 30# in the constants? As a note, my 870 prom is using a rating higher than 30#, but since I don't have the TDF for the 870, I'm not sure what the exact number is.
Chris
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408cid 1985 Corvette
http://www.mojosgarage.com
TGO Supporter
Joined: Jul 1999
Posts: 10,907
Likes: 5
From: The Bone Yard
Car: Death Mobile
Engine: 666 c.i.
The actual rating is closer to 33, so using 30 to start will give you a good measure of "insurance". Remember, that this is really just a starting point to get you in "the ball park".
Just be careful for the first little bit while you are monitoring your BLM/INTs for part throttle. If you are WAY OUT, just modify the Injector Flow Constant again.
Just be careful for the first little bit while you are monitoring your BLM/INTs for part throttle. If you are WAY OUT, just modify the Injector Flow Constant again.
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