Anyone ever tuned a high HP normally aspirated 94-97 car in speed density? Will it work on a street driven car with a 4L60E? Was talking to a tuner and said it works well in the LS1 world, what about the older 94-97, or more specifically a 94 OBD I car.


David

 

There are a large number of higher HP applications being daily driven with speed-density tuning, but a lot of them, like mine, use aftermarket engine management systems.

Are you asking specifically with reference to the stock 1994/95 PCM?

 

Yes, stock ecm, I talked to Jeff at Thunder Racing, that is where I got my info, also Ed Wright said he has dabled in it also.


David

 

I suspect if you just posted on LT1/LT4 Engine Tech, or on the Computer Diagnostiocs/Programming forum you would find people runnnig speed-density on the stock 94/95 PCM.

 

Really? I know of no-one in my area who has done it on a LT1 or LS1, one of my buddies is about to have it done on a LS1. And have never heard on any board of anyone else that has done it. I figured the only ones who either have done it or have heard of anyone who has would be in here. Especially on a LT1 car. Seeing as no-one has responded in here...I have my doubts in any other forum...but I will try.


David

 

Of course you can do it, its not rocket science. Its the same on ANY engine or engine management system for that matters.

i would however, NOT reccomend it unless you have an aftermarket system (FAST, etc) that allows on the fly tuning. it is a LOT more work to tune, and will get REALLY old reflashing the PCM 32632632 times.

 

Just enquiring, I was told there was power to be had there. I know speed density is not as accurate as a MAF setup and under part throttle driveability is not as good. I have a LS1 85MM Maf and was panning on using that, but am afraid it will a restriction in the intake tract. I also have a stock ported MAF with billet ends will also try it.

 

The gurus on speed density conversion are at Street & Performance.

www.hotrodlane.cc

The bread and butter of their business is helping guys transplant newer technology LT1/LS1 motors into old hot rods, which in the process eliminates the original factory MAF setup. Check it out and give them a call.

 

Probably all they do is install a 93 model ecm on a LT1..I will contact them.


David

 

I wouldn't say my car has "high N/A power" but I am running speed density.

I butchered the MAF when I was new to the car world and that was the "in" thing to do. Instead of spending perfectly good money on an unported MAF I just tossed the whole thing.

My best trap speeds are only around ~114.5 mph. There's more in her with good driving, weather, and some WOT tuning (AFR is all over the place) but I don't have the time right now. On my drive from Dubuque, IA to Des Moines, IA (247 miles) a few weeks ago I recorded 30 mpg. This was with a passenger, luggage, and the A/C blowing. Didn't measure it on the return trip but Des Moines should be at a higher elevation than Dubuque.

It does involve quite a bit more tuning and probably isn't worth much in terms of power for most setups. I am very satisfied with it though.

 

I have run mine in SD for brief periods but never went to the dyno or track with it that way. I am considering this as a winter project. Ditch the MAF and retune SD on the Dyno to compate with Mass Air numbers. My MAP drops from 100KPA clear down to about 93 or 94 KPA at 6700 RPM and although many have said the MAF is not a restriction on a 355 at 6700 rpm I want to see it for myself. It'll be a fun test. All that being said, I wouldn't consider my car to be "high horsepower"

Steve

 

FWIW I had the following intake setup last fall: Stock WS.6 airbox with K&N, stock bellows, stock MAF (untouched), going into the 52mm ported stock throttle body. I was seeing upto about 3" of vacuum in my 383 at 6700-6900rpm. I have since switched to a C5 K&N FIPK with the smooth bellows, still have the stock untouched MAF and also put on a monoblade. I now see 0.5-0.75" in that same range. The car definitely pulls harder up top than it did before, and puts my calculated shift points in the 7000rpm range.

Chris

 

http://www.maftpro.com/

 

Might be useful on a car where the pcm is not so easily accessed but with the easy access to our pcms I would call that the halfassed way of doing things.
There was a b-body guy running 11s on spray who swore he could completely tune the car with a translator and had the suspension setup so he had it deadhooking. Eventually he tried a pcmforless.com mailorder tune and had traction problems all over again and gained 3 tenths. Three thenths on a 11 second car is huge.