Hey, I can't seem to get my IROC-Z over 90 on the freeway in overdrive. In a few months I will put a full 3" exhaust with no cat into a Spintech muffler, will this help? Later projects might include ignition upgrade, computer chip, K&N filters, air foil, and maybe headers and a 3.42 rearend. How far do I have to go to hit magic 100 mph? Engine is currently a stock 5.7L 350 TPI (1989.) SUGGESTIONS???????? -89IRO

 

Uh... you've got something seriously wrong! I've had my 2.8 over 120mph. Your stock IROC should have no problem reaching speeds of 135 or higher.

 

i agree with the other reply....sure you dont have the brake and gas pedal mixed up? (just a joke, not trying to offend). small 4 cylinders can make 100 without too much trouble....now a 350 v8 should easily go above and beyond 100. how does the car sound when you are accelerating and when you are at max speed?

 

my 88 2.5L 4cyl fiero can do over a 100!

if your 5.7 can't get there somethings very very wrong...

plugged exhaust,crushed catalytic converter, would be my first guesses, but you have to give more info. how the car sounds, what kind of gas mileage it gets, if the tranny is slipping, 1/4 mile times, etc...h

 

Is it struggling to get to that speed or does it just stop and feel like it can go more?
Maybe the throttle get stuck on something and can open all the way?

 

Is the e-brake on?? I agree, you should be able to do that easy.

 

Guys, reread what he said. Over 90 in OD. At least that's the way I read it. As in how do you stay in OD over 90mph. You have to get a different valve body for the tranny, check a GM dealer for it. I forget the part #, search the tranny board.

 

oohhhh i see what ur saying....hey original poster is that what you meant? well, im not sure about the mechanics but you can kind of do a methodical thing with the gas pedal and get it to shift and slowly accelerate over 100 without pushing it all the way down :sillylol:

 

Sorry guys, I forgot all about this board cause I didn't get an e- mail back when I got a reply for some reason. Yeah, well here's the story... I got the stock exhaust, stock engine, now the engine is very strong on the street and freeway, so I know there's nothing wrong with it. I will give it another try on the freeway soon to hit at least 100. The last time I tried, it was in OD, and yes the brake was off, my foot was down as far as it could go, and it was topping at about 90. I'm planning on getting a new full 3" exhaust w/ new cat and muffler pretty soon, because like someone says it may be a crushed cat or something. I know the cat is bad becasue it's the reason I barely pasted smog! Well, I'll give it another try I guess, thanks for the help. I'll post my results as soon as I get out on the freeway (Hafta go early in the morning on a weekend to avoid LA traffic!) -89IRO

 

O.K. I bought the car about 2 months ago and when I got it, it ran like crap. .....Bad gas mileage, poor performance etc.. Then I got new plugs in it, new plug wires, new dist. cap/rotar, new starter, new engine oil, fuel filter, oil filter, trans. flush/ fluid, and rear-end fluid, STP fuel injector cleaner, and new Fram filters. After all that stuff it ran much better and cleaner. But I ran it on the freeway after all of this. Now I am getting good gas mileage but I don't know what's up. Just thought I would give a little more info before I go and try it again. -89IRO

 

A stock 700-r4 will not run in OD at full throttle, you have to let off. There are fixes to this if you feel like tearing apart your tranny.

 

even so and regardless, you should be able to to 110 at least in 3rd at WOT.

If your car won't go above 90 with your foot on the floor, something is wrong.

At 90mph with your foot floored, what RPM's are you reading?

My camaro goes through the light at the dragstrip at 4400rpm in 3rd gear at 92mph. stock tire height and 3.23 gears.