[iroclife]

i have a 90 irocz,305 tpi. i was woungering what are some things i can do to get some more horse power out of the engine. just bought it and looking for more power out of it. thanks for the help.

[poncho62]

1st thing is a good tune up....that will do wonders.

What are you looking for? More acceleration?

If so, a set of taller rear end gears will really be noticable.

A free flowing air cleaner, free flowing exhaust (headers) will also help.

[Lonestar]

rip the current engine out of the car and put a real one in it's place.

Just kidding...kinda

Like poncho said, air intake, exhaust and a tune up will change a lot.

[segge]

Larger throttle body and air meter, just not too large, starts hurting performance.

A new intake manifold and heads would also help, but those arent usually cheap.

[Siggy_Freud]

Dont waste your time on a larger throttle body until you have upgrades such as a larger intake/plenum and heads. The 48mm throttle body is plenty to feed that engine as it is. By 90 they had done away with the Air meter and instead use a Manifold Air Pressure sensor to calculate incoming air. Dont waste money on the "air foil" or MAT relocation kit. You can bypass the coolant that runs through the throttle body with about 2 bucks worth of parts, so dont buy a kit online for that either lol. It will help cool the intake charge a wee bit.

Cheap and TPI (fuel injection for that matter) dont really go hand in hand. What sort of budget do you have? Id get some headers and better exhaust (assuming its stock). Not really much you can do with the intake unless your prepared to throw down some fairly large $$$'s.

[Rhansen]

Second the exhaust. Headers and a cat-back should be worth .2-.3 ET. Most of the other stuff advertised as bolt-ons are worthless.

[docvette]

Originally Posted by Lonestar

rip the current engine out of the car and put a real one in it's place.

Just kidding...kinda

Like poncho said, air intake, exhaust and a tune up will change a lot.

Doc here,

Leave it to you to take the sensible approach...

Doc

[coldknock]

Nitrous Oxide.

Larry

[KNanthrup]

Originally Posted by coldknock

Nitrous Oxide.

Larry

thats probably the most effective one right there

[Docs91RS]

Well likes been said a good tune-up Including a K&N filter some better than stock plug wires , cap, and rotor goes along way. The throttle body coolant line by-pass that was mentioned is a great budget mod. Headers and y-pipes for these cars aint cheap, but you might find a deal on some used. Cat back exhaust systems like the one flowmaster offers are relatively cheap and give you a measurable hp gain plus sound mean too...lol. Improving the cooling system on these cars helps performance as they all came from the factory designed to run in the 200 degree plus range to keep emission down. I would recommend a 170 thermostat which they dont stock anywhere but is available form chevy (forget the part number at the moment. Then install an adjustable fan themostat to your electric cooling fans so you can set your fans to come on earlier. If that sounds outta your league then just get the JET Performance fan sensor that that directly replaces the stock one. It turns the fans on at a much lower temp. You could also get a performance computer chip, they have a much more performace oriented programming than the factory. Depending on how brave you are and how warn out your engine is and small shot of nitrous in the 75 to 100 hp range would really wake that thing up, but I warn you it is addictive...lol If your looking to get inside the engine and you dont mind droppin alittle more coin they make plenty of mild performance cams that dont require computer mods to work. Ive also heard good things about the new holley stealth ram which directly replace your stock TPI intake. It uses you stock sensors, injectors, harness and etc. It seems to be worth some serious HP even on the 305. If ya decide ya want more your just better off droppin in a 350 with the same mods and be done with it. Good thing about it is everything you've bought for the 305 up till that point will bolt right on or in the 350 provided its a post 87 350. hope this helps

Doc

[Max Keith]

A less restrictive air filter and a free flowing exhaust system are the easiest to go with and may well be the best bang for the buck. After a good super tuning.

[iroclife]

i figured a couple of things on my list for now till i get it paid off is. functional ram air hood, super tune as he says, full exhaust system. i would not mind some more info on the thermastat and some headers. thanks. i also have a 78 trans am i will start working on when i get this one little better. Thanks all great help.

[Siggy_Freud]

The stealth ram, while a good intake, is expensive (as stock fuel rails will not work) and doesn't work with a MAF type setup (without some modifications). You must also replace your distributor with a small cap and remote coil. And you'd have to get an adapter (or make one) to plug your stock harness into the different cap. It would be a downgrade on the ignitions system unless you replaced with some high quality parts as that particular GM HEI was one of the best made.

Dont bother with the JET chip. Wait till you have a few more mods, and then at the very least, have someone program one FOR you (same cost most of the time). It still wont be very custom, but at least it will be more tailored to your needs. On their chips, Jet changes fan kick on temp, and bumps the timing up a few degrees. Thats about it.

Those cars can actually benefit from some underdrive pulleys. Put some in an 85 Corvette and it made a noticable difference. Also bought an adjustable fuel pressure regulator to play with the fuel pressure. That helped as well. The latter is a good investment for tuning purposes.

[Max Keith]

Siggies got some good ideas with the underdrive pullys. Dont totally agree with him on the JET computer chips, however, the JET chips are the only ones Ive had experience with, and there are a lot others on the market.

[Siggy_Freud]

I've been doing a lot of reading lately on chips because I am getting into programming my own (thanks to the encouragement of Edge). There have been a few programmers that have scanned and downloaded the variables from the Jet chips, and have found that despite a fantemp change, and bumping the timing 8-10 degrees, nothing else is really done. While this will help your performance, it no way is it tailored to your vehicle specifically. For the same amount you spend on that chip, you could buy your own stuff to program chips (though there is quite a bit of a learning curve involved as I am finding out), or at least pay a programmer to do one better suited to your needs. Most programmers will reprogram a chip 20+ times for free as mods are made to get the best setup working.

All in all there are better things to drop 300 bucks on than a generic chip.