Earl 87gta

I had a melt down and have to replace my wirring harness and I thought abought going with the accel harness and cal map soft ware I was just starting to get in to burning my own proms when this hapend my ? is If I go to the excell set up can you tune every thing that you could tune from the gm set up using tuner cat and burning my own chips or should I gust go back to the gm set up. I m also woundering abought my gages i was told that they would not work with an after market harness has any one found a way around this so they can use the stock gauges.

a383z

iTrader: (2)

I figured the more knowledgeable people would answer this but they didn't so here I go. In my opinion the gm computer is like comparing a cavalier to a corvette good and nice even cheap but no where near as good. I had the stock computer in mine and had a couple of chips burned by "great prom burner" with expierence. The car ran great no major complaints plenty of power. I got an Accel ECM on a GP. So I had it installed. I had this guy called Jims Performance in Ellicot city, MD install it he put in a very basic program in so the car would run and it ran way better than before. That is without tuning it while driving it which is what your suppose to do to get maximum performance. when I got it back the car idled better and ran better no more running rich. To me it had the smooth touch of stock and the ***** that is should have had cosidering my setup. And all my guages work perfectly with an adapter. So if you have any questions look up jims performance on the web and call him, ask him about his vette.

jtmiller92

iTrader: (42)

a383z -with the DFI did you get to keep all your guages functional...what about the speedo? Did you keep your existing harness or was it replaced? i was checking out jims site last week and he said he could modify the stock harness to work with DFI...I've been thinking alot about burning proms but the DFI seems to be an easier way to go......sorry about all the questions,i'm still learning...I grew up on carbs and just recently starting dabling in the efi realm.....

Keith5

What about cost? How much can a DFI system be gotten for?

a383z

iTrader: (2)

All my guages work even teh speedo he has to use some kind of harness to make it work and depending on the car makes it depend on which one he uses. There are two choices either buy a jumper harness so you dont have to cut up yours or have him adapt my harness. I had him modify mine cause I am never getting rid of the car "taking it to my grave" In my opinion you will make more horsepower with DFI than burnig proms(MY OPINION) and I think its easier. Earl I would way the cost of buying a factory adapter and modifying it and the cost of a Accel harness but I wouldn't go back to burning proms when I break something in my car I upgrade If its feasible so a burned harness is a perfect excuse to upgrade. I think the only reason burn chips is because it cheaper and easier not because it will make more horsepower than DFI(MY OPINION) If anyone has anymore questions I will be glad to answer.

Grim Reaper

The HP is all in the tuning. Putting DFI or using the GM ECM on a basically stock engine SHOULD result in the same HP/TQ when BOTH are tuned properly.

There are advantages and disadvantages to both. First, if your engine is making a LOT of HP where you are needing very large injectors or making peak power past 6,400 rpm (plus some DFI support a 2-3 bar map for a power-adder), you probably will have no choice but have to use DFI. But for a 350 HP engine, DFI and the stock ECM (when properly tuned) should give the same results.

The stock GM ECM also has a lot of advantages - it's definitely emissions legal, there is the Highway Mode logic that can be invoked to increase gas mileage, if you ever have a problem you can get a replacement fairly easily and cheaply (especially from a wrecking yard) and you can retain your VATS. Also, not all DFI are the same. Some are more limited and not able to control as many of the stock.

Some of the DFI systems allow for "programming on the fly" which can be nice, though I find it better to capture data so I have my engine tune optimally for all conditions in all weather. Plus I can concentrate on driving the car and not have to constantly look at the screen.

On the ECMs that our cars use, virtually all of the guages are not controlled by the ECM (except possibly the digital displays). Also (for TPI) GM used 3 different ECMs. The earliest MAF TPI there is very little info for and people generally change to the 165. And of course there is SD. Most DFI systems that I am aware of use SD and you really need to compare them to each other.

One of the reasons people convert from MAF to SD is because if/when you need to alter the "fuel tables", altering the MAF scalar tables is quite tricky and generally something that should not be attempted by the "newbie". The SD system is very similar to most of the DFI, you make an adjustment to a particular load/rpm "cell" in a table and don't affect anything else. In many respects SD is easier to tune that MAF due to this very reason.

RCR

Glenn, you're starting to sound like Grumpy, but I agree with everything you said.

Earl 87gta

Thnks for the info Im going to get with jims performance and see what he charges for this.

Grim Reaper

Well thank you Rob (I think)

DFI definitely has its place because there are definite limits to the stock ECM. Right now I am helping a buddy with a MAF system on an engine that we expect to be pushing well over 500 HP at the crank. We well expect to go SD (though we are amazed how far we've been able to push the MAF system) and he may even have to go DFI.

The problem is the injector sizing. We are already exceeding 80% DC with his SVO 30#s (though he still crank fuel pressure a little higher), but it may not be enough. We really need to get a WB O2 sensor controller built so we can monitor his AF ratio.

With the high impedence injectors for the stock ECMs, we are limited on how high of a flow we can go. Idle becomes the problem because the larger the injector the smaller the pulse width we have to go while at idle. The stock ECMs can only go so short on the injectors pulse width. If he steps up to 36# injectors (to ensure adequate fuel delivery) for WOT at 6,000+ rpm, we may find that we cannot set the idle properly.

At that point, he may have no choice but DFI.

a383z

iTrader: (2)

Earl that is one of the reasons why I went to DFI because I also use 30 lb injectors. But I am glad that some of you more knowledgable people answered some more questions cause honestly my expierence comes from my own trial and error but there are few TPI in this area that I have seen that have gone as far as I have. Thank you guys for the more info.

Earl 87gta

I e-mailed Jims Performance left them a msg on the phone but they said on that it would be a few days before he could get back to me. But I did get a reply from e-mail saying he could addapt a gm harness for 100 but he didnt say what else I would need for the convertion I got my hands on a harness out of a z28 so I have one I can convert but know I need to know what else is needed just the calmap soft ware or is their somthing else I would have to get just woundering if I still need to buy the accel harness he didnt say can you get the accel conputer with out buying the wireing harness I hope you guys have more info on this. I know I will be changing to a SD from the MAS air so I will need a map sensor but what else will I need . thanks for your help.