When you pull the fuse, you lose the long term fuel corrections.... whether they are "good" or "bad". Whether he would gain any performance depends on what the BLM's need to look like to fuel the engine correctly, compared to the 128 they will be at after he pulls the fuse. The PCM can only learn when its in closed loop, and the BLM's in each cell are only adjusted when the engine is actually operating in that cell (defined by MAP and RPM). If you pull the fuse before you run it down the track, it will not be able to alter the Cell 15 BLM's, since you will be in power enrichment mode.

Its just so easy to pick up 12HP or so by leaning out the stock tune in the PCM's PE tables. That way your BLM's will develop the way they need to, and the "gains" of leaning out the overly rich stock tune will be constant, not hit-or-miss.

 

Injuneer:
You're right that "hit or miss" isn't good. I got the impression he was not allowed to "massage" the ECU by re-programming so he was trying to be "creative" around the margins.

 

Its a bit confusing to understand how they would not let him program the PCM, but would allow him to install an aftermarket AFPR. Maybe he'll clarify.

 

If you are referring to me, it's a simple matter of policing.

Camaro/Mustang Challenge is a road racing series pitting 3rd and 4th gen F-cars (82-97) against Mustangs (79-95) in a series based upon the old Showroom Stock series in SCCA years ago.

So, modifications are very limited. The series is governed by a rule set which pits driver against driver and not necessarily checkbook against checkbook. The racing is extremely close and very exciting.
http://www.lawmotorsports.net/mw/vid...R2_1st_lap.wmv

The ability to go in and modify the PCM in later year model cars is strictly forbidden because there is no easy way to police 30 cars in a timely manner.

But, an AFPR is easily policed as a fuel pressure gauge is a required component on all cars.

When the car is dyno certified, the fuel pressure is noted. If it varies outside of tolerance, a driver risks a DQ.

To further clarify what I'm trying to do, is alter the area under the curve to my advantage and not gain a peak number.

To get an LT1 down to class maximum HP/TQ, I have to install a restrictor plate between the TB and intake. It's a significant restriction, resulting in the motor running out of air at 5K rpms.

Looking at a typical dyno graph, the motor's peak TQ number spikes at about 25-2800 and drops off alarmingly fast. I'm trying to move that peak or soften the slope of the drop to get more usable TQ, ideally, in the mid 3Ks.

And I can only do this with a bone stock motor and very limited use of aftermarket parts.

The new motor has taken advantage of every tolerance found in an effort to find out if moving that TQ number is possible.

For instance ... stock compression is 10.5:1 +/- 0.25. I punched the motor to a 355 (allowed) and used thicker head gaskets (allowed) in order to LOWER CR to 10.25:1. This will allow the use of a larger restrictor plate and more air to flow.

It's a whole different mindset. Anytime I ask a technical question it's often received with a snarled face. Anything done to BUILD power just has to be restricted. So we're building longevity and hoping to gain an advantage by working smarter.

HTH and thanks for the discussion.

 

Who's afpr do you guys recommend to buy? Holley, DFI, Accel?

 

I hear GOLEN RACING ENGINES recommends an AFPR , BUT they also use 30# injectors for 500 hp engines. My setup is going to use 42# injectors at 475 na hp and 600 hp with a 125 shot , so from what I understand from this thread , I dont need an AFPR ... right? ---

 

I know what you are getting at, but to clear it up for any newbies who may be lurking, flywheel horsepower dictates fuel needs, not rear wheel.

370rwhp through a geared and stalled auto is very different then 370rwhp through a bone stock M6.

Just clearing it up - I get what you mean, but others may not.