OK guys, here's a loaded question for this group....

I have DFI spliced into my factory wiring harness on my '91 Corvette. It used to have a 350rwhp 355 with 30# injectors so I needed some tuneability and this was before the DIY stuff was really out there.

But now, I'm putting in a stock L98 motor with a SuperRam, headers and exhaust and I'm wondering if I'm better off staying with the DFI or splicing the stock ECM back into place. I figure a stock L98 with better intake and exhaust would not require major changes from stock, but if I could tweak the PROM with tunercat or something - maybe add some timing, and add both timing and fuel above 4000rpm, it seems it would be easier to get it really dialed in that messing around with DFI.

Any opinions on that?

Scott

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'91 Corvette 6-speed coupe

 

Hrm, rather a question of what you -feel- like doing. Although the stock ECM would probably be okay with those modifications, why not stay with DFI if its already there? Less hassle i would think.

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89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-MSD 8.5 mm plug wires
-Gutted cat
-!AIR

 

Of all the ecms/eproms to tune, the SD system is definitely the easiest in my opinion simply because of the amount of information available for it.

I cannot comment on DFI as I have never played with it. I do know that a few people have come to this board with DFI, but there just aren't enough people with it to offer any further information on it. But, maybe if a few more people with DFI start participating on the board, then a body of knowledge would develop.

 

Kinda expensive to carry a spare DFI, since they do fail from time to time. I carry a spare that cost $35.

 

Personnally, I'd go with the oem one.

 

Well, my thinking is it would actually be easier to make small tweaks to the GM code than come up with as good a program on my own from scratch with the DFI. Especially in part throttle and cruise conditions the stock program should work better than anything I could come up with using DFI, unless I played with it constantly, then maybe I could get the DFI close....

But I hate to go back to stock and then wish I had DFI when it comes time to build the motor. although it sounds like quite a body of knowledge is growing out there in GM ECM land now, so maybe not to worry bout that..

Scott

 

Hey Scott! Welcome to the PROM board. I've read (probably on one of the boards here) that DFI has control of less things (big tech word there!) than the OEM computer, and the part-throttle and cruise variables really need some work to get them dialed in (and some of them are missing), unlike the OEM. From what I've heard/seen, Tunercat is the way to go for programming the SD cars, although GMEPro (DOS-based and takes up a lot less memory) probably has a definition file for the '730 ECM too. Can you program DFI on the fly, or do you have to shut the engine down to make changes? Since you have to remove the PROM/memcal from the ECM to make changes, that might be a deciding factor, but it isn't a big deal to me since I just leave my ECM on the pass. side floor.

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Greg Westphal
'87 IROC 305TPI/A4

 

The accel/dfi can be tuned "on the fly", that is the main reason I decided to go with it. It did take a while (a couple of months) to get it tuned just right, but I assume the same is true about stock prom burning.

F.Y.I. I know of three other dfi users on this board which you might also want to look for;...RCR,BOWTYE8, and 406TPI...I'm sure there are more, I just know of these three.

[This message has been edited by TunedPort350 (edited March 30, 2001).]

 

if you have the DFI, stick with the DFI. Usually you will have to get the motor dynoed and set up with the DFI by a professional tuner. then you dont usually have to make big changes with it. it takes times to get used to it...but you eventually figure it out

 

I have a DFI and like it alot.
i use nos with my car and find it is alot easyer
to use the nos config on the dfi rather than
moving my distributor around each time i use
it like in the old days whin i ran a stock cpu.
also i really enjoy tuning it on the fly
helps me get the max out of my car.
if i was going back to a stock config i might
use the stock cpu only becouse it is allreay
set to that motor but not if i used any power adders

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