Hi ,I am looking for suggestion's for effective and reasonably cheap mod's to my 89 firebird 350 TPI . right now it's bone stock, What's most effective for the money? air filter,fuel regulator,exhaust etc thank's SR

 

K&N for sure
replaceing your fuel filter
air foil

it all adds up and helps headers is always a good place to start

 

The 350TPI is a pretty fast motor to begin with -- just keeping it properly tuned means it will be fast (I know stock is never FAST ENOUGH ! big-wide-grin). My point is make sure the engine is making the factory spec 235hp and 335lbs torque before you start in on any mods. Eg: is your fuel pressure correct at wide-open-throttle ? Is your voltage across the plug at factory spec (GM coils are notorious for aging and power loss) ? Are your injectors reading the right voltage and when is the last time they were back flushed ? Is you catalytic-converter 12 years old and hopelessly plugged up (if adding a 2nd converter adds another 10hp what does plugging up a single do ? Subtract 10hp ?!?!?).

Couple of easy mods:

I have a '91 Formula with a similar stock air breather setup. This is an easy upgrade. Introduce a K&N type filter and do-it-yerself plumbing from the MAF (are you MAF or SD ?) to the fender well and you will definitely see some mid-range and top end improvement.

Put on an throttle-body airfoil and mod the TPI plenum clearing away the intrusions blocking airflow at the EGR vents (right) behind the TB.

Under-drive pulleys -- some like these, some don't. I like them because they are cheap and give me an honest rear-wheel 10hp.

Flowmaster muffler -- won't really add power but they sound great.

I think that somewhere on the board there is a free mods section that you can check out as well.

Good luck and let us know how it goes,
RP.

 

When I first got my car, and it was bone stock also, I started off with a complete tune-up to make sure it running up to snuff. The tune-up included; MSD 8.5mm Wires, MSD GM Blaster ignition coil, MSD Cap and rotor, autolite platinum plugs, 160* thermostat, and holley airfoil (pain in the a$$, recommend a different brand). These didn't help much, because my computer was shot (found that out late last season) but it helped a lot even with a bummed ECM.

Exhaust is a HUGE start, I shaved 1 full second off the 1/4 mile (this is even with a bummed ECM), and it sounded mean too The system I got was completely custom. He cut the y-pipe right after where the right bank of cylinders enters, there is metal sticking down half way into the tube from the right bank exhaust pipe, so he used the plasma cutter and cut those out, then welded the 3" at that point (headers and y-pipe are soon to come). From there its all mandrel bent stainless with a high flow cat and flowmaster muffler. Excellent job... you can see pictures of it on my website (excuse the dirty undercarriage).

 

Thank's for the idea's guy's a major tuneup is in the work's,I think I will try to build a cold air setup next week as well , the only probem is that the evap cannister is in the corner that I need to put the filter in(to get away from the hot air around the rad) hopefully I can adjust everything enough to make it fit. The exhaust work is also undoughtably a good idea However considering the firebird is the only one of our five vehicles that doesn't have an exhaust leak i am guessing my better half wouldn't be all that impressed with me tearing the existing exhaust apart to replace it......lol thank's again

 

BILLZ88350 relocated the canister behind the front nose. SLP's cold air box is a nice setup, and all you need is the box, and some smarts to relocate the canister.

 

Here's my 2 cents. First, get a tune up. Most TPI engines don't run properly. Do fuel filter, plugs, wires, cap+rotor, and zero the IAC................

1. Cat-back exhaust kit

2. Adjustable fuel pressure regulator

3. Have timing advanced to 8-9 degrees

4. Ditch the GM coil, they are garbage

5. Have TPS voltage set to .56V

6. 170 degree thermostat

If you want to buy an airfoil, go ahead. They don't hurt the power. Try to find one used or get one on special from SLP.

 

Hey Snowracer nice looking Formula. Check out the pic I attached. I have a '91 Formula which uses a bolt-on setup for the air-filter, I think yours has three clips ? I cut-away the metal around the filter and this works pretty well -- not as good as a cold-air element in the fenderwell but for 15-20 minutes work hey who is complaining ? If you want to try this mod and don't have a bolt-on unit like mine and you can source a bolt-on unit from just about any V6 Firebird at the wreckers.

Also, will we be seeing you at Grand Bend Motorplex during the May Long Weekend ?

RP.