89406Iroc

I have a 89' Iroc with a 406 AFR heads, roller cam etc. The motor is pretty stout and I want to learn more about engine management on it. I have looked at doing my own proms but am checking to see if there are any piggy back systems that I could use. This would be my first jump into programming so I want something fairly straight forward but need to have flexibility. I have all winter to play so I'll hopefully be pretty comfortable come spring. Thanks Chad

RCR

I think just from a reliability standpoint, PROM burning would be better than a piggy-back system. Unless your system neccessitates the use of an aftermarket ECM or you have your heart set on it, I would recommend staying with the factory ECM and learning to program it.

Grim Reaper

With MAF cars, the biggest concern with a big motor is maxing the MAF @ 255 gms/sec. In the past, the only alternative was either convert to SD or go aftermarket.

I am now able to say that there ARE alternatives that will allow you to retain your MAF. I have been helping a buddy with a built 383 using MAF (we just wanted to see how far we can push it). And UNLESS you plan on reving past 6,400 rpm, you can RETAIN your MAF.

You add the extra fuel via the WOT %Change to Fuel while in PE the moment you max the MAF (need to scan the engine to find this point). Then you can compensate for the fuel all the way to 6,400 rpm. This is the same limit as SD, so after 6,400 rpm there is no point in converting to SD either. And then your only alternative is aftermarket.

Also, you can only add so big of injectors to a MAF/SD ECM. Beyond that, you need to look at low impedence injectors and aftermarket DFI. But this is only when you start to approach the 500 HP mark.

So, if you plan on reving your engine > 6,400 rpm or plan on making well over 500 HP, then you need to look at DFI. If neither of those constraints apply to you, then you can use your MAF (or convert to SD).

89406Iroc

Thanks alot---
Does the MAF effect throttle that much at WOT? As long as I'm running decent on my Air/fuel would I need to make the swithc to DFI? I am probably making in the neighborhood of 475hp. But I also run a 150hp shot of nitrous that shouldn't really effect tuning to much except spark because of it being a wet system. I pull the motor to approx. 6500-6600 Close enough to the 6400 for me. I don't want to butcher into the car because I want to keep the driveability but Max Performance. I still have A/C and a 700R4 so I need the computer to atleast run that much. Is the MAF sensor that much of a performance loss? I wouldn't want to look at doing a conversion for 5-10hp. Thanks again, Chad