ok I am putting a mild 355 in y Iroc ad I have some questions, I currently have a 305 tpi 5 spd, and i wanted to know if i can run the new 355 with my current chip?

How well would it run with this chip?

Also cani use my 19lb injectors if i turn up the fuel pressure?

I eventually plan on getting into burning my own cips but current finances and time dont allow it.

Thanks

------------------
87 IROC-z 305 TPI
Borg Warner T-5 fresh rebuild
10-bolt 3.73 Richmond gears rebuilt GM posi,
formerly BW 9-bolt w/3.45 gears(broke it)
Ported Plenum and Runners Homemade AFPR
ACCEL 8.8 wires, High output coil,and cap & rotor
Bosch platinum + 4 plugs
Ram Air w/ K&N filters,
MAF sensor screens removed, TB coolant bypass
Polyurethane tranny and torque arm mounts
No Cat, Dynomax Headers & catback w/custom tips
K&N oil filter,Mobil 1 synth,Factory Oil Cooler, Futura GLS Super Sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims.

406 siamesed TPI in progress

[This message has been edited by Fastcamaro87 (edited November 30, 2001).]

 

It'll prolly run, but it's gonna run rich.

 

As long as you run with the 19# injectors, you should run (not optimally) in part throttle. The greatest risk you have is running "lean" @ WOT.

Increasing fuel pressure will help, as you need the extra fuel where the increased pressure does its most. However, the stock fuel pump doesn't like having the fuel pressure too high or it pre-maturely burns out. If you start going above 50 psi, be prepared to replace your fuel pump regularly. One guy I know was running 55 psi and going through a fuel pump every four months.

My recommendation is to get the proper size injectors for a 350 and run the proper memcal. Start adding up the cost of fuel pumps (and the work involved), and new injectors, prom burning equipment and a 350 memcal starts looking cheap.

 

Also, if you are working on a 406 (just saw your signature), you will DEFINTELY need an eprom for that. Possibly even a conversion to SD.

The best time to get into eprom prom burning is when your engine is still fairly close to a stock setup. Easier to see the effects of various changes, yet not be so far off that your car doesn't run.

The worst time to get into eprom burning is when your engine is radically different and there isn't a stock memcal available. Most guys at that point just go out and buy a custom eprom as they can't even get their engine to run half decently, let alone make max power.

PS: While a custom prom may make your engine run fairly well, it will still not be optimal. I have been helping a friend with his 383 MAF (Miniram, AFR 195 heads) and he initially started with a Formato custom prom. The car ran well, but it was definitely not optimal.

And now for the "funny part", the Formato eprom only had about 70 differences (mostly spark table) from the stock ARAP bin. Currently my friend has over 250 differences and his car runs much better. Still far from optimal, but he's getting positive results now. But he'll have to wait for Spring to resume tuning. Just goes to show that purchased custom eproms (without any "hands-on tuning") are far from optimal.

[This message has been edited by Glenn91L98GTA (edited December 01, 2001).]

 

I used my stock 305 5-speed chip with my 350 with L98 heads, ZZ4 cam, and SLP 1 5/8" headers. But when I added an LT4 HOT cam and SLP 1 3/4" headers I had to start doing my own custom proms.

------------------
1991 Camaro Z28
5.7L 5-Speed (originally 305)
317 RWHP, 418 RWTQ
13.23 @ 107.62 MPH (2.10 60')
Southern California
Member: SoCal 3rd Gen F-Bodies
Member: SoCal F-Bodies
-=ICON Motorsports=-

 

ok heres another question, if i use the stock chip and put on some 22lb injectors, will it be ok then?

I know theres no better way than burning chips and tuning, but i need this thing for transportation, so as long as i can drive the car, it doesnt have to run perect till spring

Hey Kevin91Z
how well did the car run with the stock chip?

How long did you drive it like that?

i am also going to probably use the stock L98 cam just to keep the computer happy,

------------------
87 IROC-z 305 TPI
L98 Cam
Borg Warner T-5 fresh rebuild
10-bolt 3.73 Richmond gears rebuilt GM posi,
formerly BW 9-bolt w/3.45 gears(broke it)
Ported Plenum and Runners Homemade AFPR
ACCEL 8.8 wires, High output coil,and cap & rotor
Bosch platinum + 4 plugs
Ram Air w/ K&N filters,
MAF sensor screens removed, TB coolant bypass
Polyurethane tranny and torque arm mounts
No Cat, Dynomax Headers & catback w/custom tips
K&N oil filter,Mobil 1 synth,Factory Oil Cooler, Futura GLS Super Sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims.

406 siamesed TPI in progress

[This message has been edited by Fastcamaro87 (edited December 02, 2001).]

 

Woo! We dont need to see your long sig on every post. Thanks.

I used 22lbs injectors. This was Feb 2000 till November 2000. The car started and idled fine and I never had a problem with it.

 

Kevin had a "mis-matched system" running on SD. Since the SD could not detect the extra air flow (as yours will since you have MAF), Kevin's ECM did not know that he was flowing more air. So his larger injectors (than indicated in the eprom) did a fair amount of correction for the possibly lean condition he faced had he just used a 350 eprom.

But you have MAF. So your engine WILL detect the extra air flow and try to give more fuel to compensate. As long as the size of the injectors match what's in the eprom, you will be fairly okay (excluding the optimal part). But if you have larger injectors than your eprom states, then you will just be overly rich.

You can't use Kevin's results as he has an entirely different ECM (SD). As I said, his engine had increased air flow that the SD cannot detected and Kevin "cludged" around it (not sure if accidental or intentional).

Your engine will detect the increased air flow, so you will run overly rich with no "offsetting factors" to help correct.

An optimal eprom can make quite a difference in performance. Why go to all that effort to put in a larger motor and then negate the extra power potential by having a "less-than-optimal" eprom?

[This message has been edited by Glenn91L98GTA (edited December 02, 2001).]

 

so can i get a chip from a 350 MAF car, and som 22lb injectors , would that work for me? the computer wont care if i dont have a torque converter to lock up or not right?

what kind of differences are there between the auto and stick chips??

is the auto`s idle higher?

Oh and Glenn,beleive me i plan on getting an optimal chip, just dont have the cash or the know how right now for all the stuff needed to tune and everything.



[This message has been edited by Fastcamaro87 (edited December 02, 2001).]

 

btt

 

You'd be better off starting with a 305/5-speed MAF chip, or even better, the '91 Vette chip for 350/6-speed).

The way the idle air motor is controlled is different, plus the spark advance tables and other things. The stick chip will have a higher idle.

You'd be better off just using the chip you have in there now, stick with the 19# injectors, and save up quickly for your prom-burning equipment.

------------------
Greg Westphal
'87 IROC 355TPI/A4

 

How can he use a 91 chip on an 87 car? Also, Corvette chips have an oil temp circuit in them, that will set a Code 52 if its not present. Guess how I know.

If you're using a manual trans car, a manual trans prom is slightly better, even tho its a 305 chip. Especially on a MAF car, there's nothing in the prom (that I have seen) that shows the engine size. Thats only in speed density.