Hey guys whats up, I am new to this board and would like to ask a few questions


I am getting a 1988 Iroc-z (305 TPI, 5 Speed) this weekend or next week and I was wondering, How can I make the Iroc run 12s cheap, I know NOS is an option and I am strongly considering it. But what about camshaft, headers, and good exhaust.

Any ideas would be appreciated

 

if you want to run 12s you need to get rid of that 305 engine, its very hard to make that 170hp engine run to 350hp, swap in a 350 and it won't be to much more to get the results. but speed takes money my friend, nothing comes cheap in the automotive world.

 

If it is a TPI motor shouldn't he be starting with somewhere around 220 HP? Wether is it a 170 or 220 it's still gonna take some money to run 12's. 220 plus a 125 shot will just about get you there.

 

your right, but how many runs will he make before he cooks his engine. 125 shot in a stock 305 seems a bit risky to me, and I'm sure its not a new engine.

 

I thought TPI could handle the 125 shot

also i dont think I would use that much maybe 75HP

I would probably get exhaust 10+ HP
Air Filter 5+
Headers 15+ HP
Cams 30+

How would that setup be

 

because of the high cylinder pressure across a small surface area (due to the 305's small cylinder bore) most nitrous companies recommend 6 cylinder size shots on 265's, 283's, 305's, and 307's among others unless you have forged pistons (especially for dry systems. these 6 cyl shots are a max of 75 to 100 (pushing it) on stock motors. just as with big blocks you can go larger (barely) than the 150 recommended max for engines around the 350 cubic inches.

 

in other words its not going to happen unless you go 350 or bigger

 

anything is possible, i have a 91 rs V6 and i plan to run 12's one day. i am going to put a twin turbo on( i know some people who can help me) I am going to put a 75 shot of nitrous, and put every upgrade i can to my engine. I dont want an 8 so i plan on doing this all to my 6. You never know what is possible if you have money.

 

there is a guy that runs a 13.1 in a 305 TBI...he runs a 125shot of n2 and he hasnt changed the cam or heads..the potential is definetly there with heads, and a cam hed be in the 12's easily

 

I think it can be done. With nitrous and the the typical addons that anyone else would do. Just don't expect low 12s unless your wanting to follow ******* path

 

L2R...
I have seen a few people run as high as a 150 shot on a 305tpi with no engine problems. It seems to be the 700r4's that like to go out when you're running nitrous. They were running low 13's/high 12's with nitrous and stock everything. It isnt the best thing for the engine, or the rest of the car, but it should get you there. If I were you I'd still wait to buy a car until you find one with a 350 in good condition. Here in my area I see thirdgens for sale all the time. If you look hard, you can find a car that has been loved, and given performance parts. If you cant find one with a 350, you could swap...but if you have little or no experience it will be a major pain in the @ss. Good luck finding a car...my advise is to wait until you find a car that you really like, dont settle for something you dont really want.

-peace

 

Everyone says swap the engine. That is neither cheap or easy so I don't know what it's doing on this message. N2O is definately the cheapest way to get speed, but it's also the most dangerous, especially with that 5 speed. If you don't shift it right you run the risk of getting too much juice in the intake and then bye-bye TPI. If the TPI doesn't explode then that extra charge of juice gets ingested without any extra fuel and bye-bye pistons. On the other hand, if you really know what you're doing and setup the system right then you should be able to do what you want. I think the '88 Roc's had a pretty deep gear and that should help out too. If you have the 9 bolt then 12's are much more realistic than with the 10 bolt for that year. Running juice the right way a quarter at a time the engine should hold together. Any time you more than double an engine's designed power you run a big risk of walking home. Good Luck.

 

if you want to run nitrous run this kit

http://www.nosnitrous.com/HiOctn/Pro...NOS/gmefi.html

It is a "wet" system so it is the safest way to go. This is the kit I have seen used most often, and gives very good results. Dont listen to the people who tell you not to use nitrous because of bore/stroke of a 305...its the same (but smaller) as a 383.

-peace

 

Am I missing something here? How can something be the same but smaller? If it's smaller, it's not the same, and each variable makes a difference, especially when talking about nitrous.

 

well, actually, you can get a GM 300hp 350 and a 125 shot. Take some weight out of the car, and do 3.73' s. Some MT Sportsmans and if you do all of the work yourself, (except the gears) it'll cost you about $3000-4000. Not too bad. But 12's are tough and it might take even more than that! BTW, you may have to upgrade your fuel system and some other stuff. and you sure won't see low 12's. High at best. go w/ a carb also, it's cheap and easy, but you'll scrap emissions.

 

O2BQIK
I was talking about the bore/stroke relationship. Maybe you understand now. If not think harder

-peace

 

150hp wet kit. Add a fuel pump, a window switch to save incase you miss a shift, and a set of drag radials.

If you keep it from detonating, it will be your best friend! Just make sure it has fuel and it will be okay for a while.


EDIT: Actually, the smaller bore promotes less detonation since the flame has less distance to travel and heat up.

 

True unless it's so small that it all decides to burn at once which is the problem with the 305 and it's combustion chamber/piston design. I know what you're trying to say that less area makes less room for hot spots, but you always have to burn not explode. A larger flame front with the proper fuel and compression, and hopefully no hot spots (which only occur when the engine is not tuned right) will burn longer into the power stroke making more power with less pressure rise rate which is easier on the engine. It's the same difference as blowing up an M80 all at once, or taking it apart and burning a trail.

 

Just to add more fuel to the fire, I've been running a 150HP shot on my 144k mile L98, then for the last few months of the Summer I moved up to a shot that was giving me a true 200+ HP tp the wheels. Made about a dozen passes with it tuning it, and then went at trapped 116 mph, with massive amount of wheelspin.

Running 91 octane and octane booster, I never got any detonation, (based on knock sensor readings and checking the plugs) and the car ran like a raped ape.

I don't particularly care about keeping this motor intact, but just the fact that a motor with 155k miles has held up just fine so far to a dozen 11 second capable passes AT 5800 FEET, indicates that you can do more than what is recommended provided you are careful. I pull and check plugs after every single time I hit the button, be it on the street or at the track.