hey guys, i got an 88 iroc
5.7 tpi
700r4/trans go kit/rebuild
2500 stall converter
3.42 4th gen posi
edelbrock headers/y pipe
cut cat
no muffler
bbk adjustable fuel pressure regulator set to 50 psi
msd 6al box and coil
k&N with stock air box
hypertech chip/ 160 t stat
fans set to a switch
timing set to 12 degrees disconnected
motor is in great shape tune up wise

i ran the car about a mouth ago and ran 13.9 on street tires, leaving the line at idle to minimize tire spin

i want to get an slp cold air intake, comp engineering subframe connectors, air foil, and slp runners

heres my questions:
1.should i put a muffler back on the car? it sounds good but im prob loosing power right?
2. what should i keep my fuel pressure at? there is a chart going around online stating that 50 psi makes the best power, but everything else i read mentions that 45 is better? what is the best?
3. what should i keep timing at?
4. is there any other part that im missing that will really help?
5. is 13.9 too slow for my set up?

this car is my daily driver, and its gets good mpg and is fun but i want to go mid 13's with the car without juice or cracking the engine open.
believe me i wouldnt mine test and tuning but i live in an apartment complex so my time to tune is limited, so i didnt know if there was any golden rules with these cars?
lemme know

thanks for your time

joe

 

ok i read the thread about idiots like me who ask about fuel psi and timing, so i guess just the other questions apply

thanks

 

There are no hard-and-fast rules. With the headers, gearing and converter, you're already not stock, so you'll have to experiment.

What are the details of your better runs, anyway? 60', 1/8th, trap speed? Through the traps at what RPM?

If you are on street tires and launch at 900 RPM, you might want to consider a little suspension work (will work well with the SFCs you mentioned on your wish list), sticky tires, maybe some adjustable shocks, and allow yourself to launch a little harder. You could easily be in the middle of 13 with a good 60' time, without turning a wrench.

What are the bolt-on mods? That may help drive the direction. The SFCs are always a good idea. The CAI you are contemplating can't hurt. The air foil is not worth the time, unless someone is going to give it to you. I wouldn't waste $10 on one. Want mine? The larger runners can;t hurt, but you might not realize their full potential without cam and head work.

Maybe a good PROM calibration would get you even lower. I'll bet with just your headers you're already not making your full potential on the stock PROM. Set the fuel pressure back to stock (42-45) and tune with the program instead.

 

To get your E.T. down you pretty much do need some better rear tires. Sometimes LCA's or LCA brackets will sometimes do the trick though.

You may find you go faster with your stock chip, so you should try that.

Tuning your own chips is by far the best way to go, but if you're not going to do that you're just left with some simple tricks that may or not get you the results you want.

One thing you might try with the stock chip is to lower the fuel pressure back to something closer to 40 psi, and plug off the vacuum to the regulator. Finding the right pressure is a matter of driving around with a scanner watching your BLMs. Once this is close it should leave you leaner at WOT which generally makes more power.

Driving to the track with a stock MAF and then switching to a gutted MAF before your run will also usually lean the WOT and show a gain.

I don't know if you were looking for those kind of "ghetto" tricks or not, but you don't have far to go to reach your goal.

Oh and I doubt that you would pick up power by adding a 40 lb muffler, but if you need to make it quiet pick a straight-through design (not a crossflow) that's at least 3" like the Borla. At least you shouldn't lose much power at all that way, and be quieter.

You didn't say what octane you were using in the car, or if you were mixing in race gas. In any case, don't put the race gas in your car. The increased octane will slow you down, and additives in the race gas damage O2 sensors. You might want to do a test where you lower the octane. It's not so uncommon for cars that run cool to pick up power with less octane.

 

Throw away the 160 t-stat.

Put in a 180

Throw away the Hypertech "chip" and just run the stocker.

Get into "prom" tuning, the real kind, not we add excessive timing at 100kpa hypertech kind. We have an excellent board here on it.

later
Jeremy

 

hmmm lots of ideas. . . .well ill deff set the fuel psi down a few pounds. Where can i get a stock rom? the car came with the hypertech chip, and that was the only mod the car had. As far as gas, ive been running 92 octane gas most of the time, everyone once in a while 89. When i ran the car i got a 1.8 60 foot time when i left the line at 900 rpm, however when i torqued the car up to 2000 i got a 2.3 60 foot, so traction is an issue in my case. And off the top of my head, i believe my trap speed was 96 mph.
so heres what i gather. . .

cold air ok
exhaust, leave it alone
return the air foil
set fuel pressure back
sfc's good idea, maybe some better tires
stock prom or custom burned prom
180 degree thermostat

sounds good to me, my sfcs and cold air should arrive monday, ill get a 180 t stat, try to find a stock prom, set psi to 45 and hopefully get a track run before the track closes. .. .

thanks alot guys!!