vader86

No the 85's injectors are rated 24lb at a lower pressure of like 35psi, not 30lb. It is stated in the OP's linked post and has been verified here many times. In 86 they dropped to 22lb/hr rated at a higher pressure of about 45psi, so they end up flowing about the same rates in practice, but the computer is adjusting them a bit differently (different computers between 85-86). The 85's injectors running at the higher pressure will flow more than what 86 has however.

It is not like you need that fuel because the TPI chokes the hell out of the motor.

And Yariv, no you have not done enough to warrant messing with the fuel pressure yet. Spend your money elsewhere for now.

aklim

You mentioned street use. You are right. At WOT, it runs whatever was programmed regardless of the O2 sensor reading.

That is at WOT but what happens when you are going downhill at a relaxed pace or even in the city driving mode where it isn't WOT? Assuming the ECM can adjust, maybe it won't be so bad. OTOH, if it falls outside the adjustment window, you run rich. Maybe it is better to adjust the EPROM to advance timing or change pulse width instead of trying to fool the program.

aklim

But wouldn't it be better to stop screwing with the fuel pressure and just make the changes in the chip so it works throughout the band instead of band aiding the thing?

BlowerWorks

Hi There !
The way I like to do it is sell you the following:
> Cable to data log with using TunerPro RT.
> An Ostrich from Moates so we can exchange BIN files after examining your logs.
> After any number of iterations you may then be ready for the dyno if desired.
> Also prefer to sell you a new MAF - slot style matched to your power.
All of this can be quite expensive but in the end well worth it if you cannot do for yourself.
BTW the guy that tunes my L98 MAF cars is Tequila Boy who runs an '87 and is quite the expert !!!!!!!

aklim

If you don't have a dyno facility that can tune it for you, a datalog tune would be your next best option. Below that, get someone to tune based on your mods.

http://www.hitechmotorsport.com/tuni...category_id=76

Yariv

Thank you

vader86

I see OBX headers, exhaust, and TB. That tells me he hasn't really done enough airflow modifications to justify the expense of a customized tune.

I would hold off on that until some other things were done, or if he was totally finished with mods, or got a good deal on tuning cost.

aklim

Kinda why I suggested doing a good intake. What is your thought on that? Headers, intake, exhaust and a dyno tune? Before that, leave it alone till the intake is on.

Yariv

I sent an email to http://hitechmotorsport.com/. Wait for their reply to understands my ECM options.
If the ECM tuning/get a new chip can be done, I'll go for the OBX.
Regarding the MAF and air box, I read an old post of Vader86 explains there is no need for adjustable MAF.

vader86

Don't bother with the adjustable MAFs, waste of money. Airbox is fine.

You really need to think out what you want to do with the intake setup before going the route with ECM tuning. You won't get the bang for the buck. Let it inhale, then you can start playing with pressure regulators and ECM tuning on a dyno.

aklim

Or you can give Bart a call. 763 712 9088. Much faster that way

Yariv

Hi,

Here is an answer from Brat: "Tuning with your mods is not worth the cost. Headers and exhaust will not change it that much either. The best mod for your car is a gear change to 3.73/3.90/4.11."

So, your answers point me to leave the Vette as is.
Thank you all.

vader86

Bart likely thinking of a late C4, not an 85. Do not think of changing gear ratios.

Yariv

Sure, I won't touch the gear....
I wrote him its a 1985 Corvette.

aklim

Well, if that is their answer I'll go along with it. They have been honest enough with me in the past to tell me what to do and more importantly, what NOT to do. Now if you decide to sell your wife and kids into slavery and mod the hell out of your vette, you know that they will do it for you, even if it is not worth it.

To be honest, the only time I felt a difference in my F-body is when I did intakes and headers but I am not sure how different the F-body programming is from Y-body. That was done by Lingenfelter when he was alive.

aklim

I don't know if my F-body was that different but I went from a 3.73 to a 4.10. A little more pickup but gas mileage sucked. For my combination, they told me to go with a 3.54 gear but I knew better. I also got to know the gas station people better too. I should have piched that rear end for a Ford 10 inch or a Chevy 12 bolt instead of trying to make the 7.625 rear end work. Spun the bearings, broke gears but I knew better.