Hello everyone, just looking for some advice to upgrade my 350 TPI and get some more horse power out of it. I know the obviouse like headers and exhaust, but I noticed through reading that a big problem is the air intake. So if you can let me know some ways to up grade this a long with other things that would be great.

Thanks

Nick

 

I am asking the same question right now. They say air flow both in and out of the engine is , well junk in its stock form . What I have learned from some of these guys is that replacing worn stock parts and a little upgrading will make a world of difference .

 

Ya totally make sence, but what are the parts that should be replaced, and what are the parts that should be upgraded???????

 

Well I am currently replacing my fuel injectors with a set of bosch 3's. The guys around here say that they atomize the fuel better resulting in better performance and MPG. I also am porting and polishing my stock intake system which should help my top end flow a little better . As for the exhaust , I just put on a set of headers and a hooker cat back .

Future plans include a set of aluminum L98 corvette heads (whitch will be ported and polished), MSD dizzy , and a few other odds and ends . I am going with those heads because I am not building a race car here . Also they are cheap and are all over the place . The set I am getting are already ported and polished for $450 . Oh also thinking about going with a stock LT1 cam . Need to look into cam options though.

 

Do a full tune up: spark plugs (cheap AC Delcos are great), wires, rotor and cap, id swap out the MAF sensor relays too. Cleaning the Throttle body isn't a bad idea either. Check your timing and fuel pressure. My stock Fuel Pressure regulator was shot and I was running 53psi and performance sucked. Also, make sure your trans is shifting at the right rpm. Should be 5000 or so from 1-2 and 4600 or so from 2-3. When I got my car, it was shifting at 4000. Basically before you do any modifications to the motor, you want it running in tip top shape like it did off the showroom floor in 1987. Trust me it's worth it. I wanted my GTA to run 14's bone stock, not modified if you get my drift.

After all that, first mod should be drag radials on a spare set of wheels. Mickey Thompson ET Streets are very good. That way when you go to the track, you will be consistent. Nothing sucks more than 1 high 13 second run and 10 low 14 second runs. You want back to back to back 13 second runs.

If you have 2.7x gears, your first mod should be a set of 3.2x at minimum. You can find complete rears for around $2-300 or have a shop do gears for the same cost. Its up to you. If you have 3.2x gears, then your good for now. Move onto a 3" catback exhaust. Brand doesn't matter, just pick one based on the sound you like. Then headers. After that a shift kit and a 2800 stall converter and you should be easily in the consistent mid 13's depending on your elevation. Once you get there, start looking into TPI modifications. TPI is awesome down low, around town and makes a very fun street car.

 

Good idea on the fuel injectors, forgot to mention that in my novel above haha.

As for the LT1 cam, its BARELY any bigger than what you already have. Don't waste all your time and money for 10hp.

 

anyone know why cruise control works bu slowly idels up, mabye vacume leak

 

Well I was looking into that cam because I picked one up for $20 And with a set of 1.6 roller rockers I would be at my max lift with the stock heads .

At this very moment I am taking off my TPI system waiting on the arrival of my injectors and I have to say I was amazed how much crap has built up in my throttle body , plenum , and runners (and my car has 90k miles on it) It cant be doing my motor any good. So with this new found info , I would suggest injectors and clean the hell out of your TPI system . I will post a few pics of what I found in a few.

If you are interested in the injectors , I went to FIC (fuel injector connection) . Picked up a full set of bosch 3's along with the whole TPI gasket kit (with fuel rail rebuild kit) for $187.

 

The best thing you can do on these motors, as you mentioned, is get the air in and out, which means an intake and exhaust. Make sure the car is in good tune. Injectors will not add performance, they can result in a better idle, smoother acceleration so that's a good thing you did that.

 

True . I ment better performance in the sense that 2 of mine didnt work at all . So replacing them would result in better performance in my case

 

How much extra power do you want and how much money to spend? Headers, exhaust are are very worthwhile. You can cut off lower air baffles on air intake lid. I found a junkyard lower base and cut off baffles so I could save my stock unit. That will help increase flow a bit. Next consider larger aftermarket TPI tube runners and base. Stock tube runners are restrictive. Changing to larger runners alone will help. Search around here for ones that work (AS&M, TPIS and not Edlebrock). They will run around $400 a pair but you might be able to find a good set used. Can look for some used heads. Just make sure that they are better than stock and will keep compression ration similar to stock. More aggressive cam would help. There are cams that will give performance boost without needing to retune your cars ecu. I can't remember what they are though. Good luck!

 

It's always a good thing to have all the fuel you need...

 

Hey guys, thanks for all your posts. They were are very helpful and gave me a couple things to think about. Roc This, that would be great if you can post those pics on here for us to view. So I'm not exaxtly looking to do some crazy stuff to the motor, I'm more looking to do simple things like you guys have mentioned to optimize my performance. Any more suggestions would be great.

Thanks

 

I've got an 87 350 TPI as well. Ceramic headers and a 3" catback its a quick car... next on my list is the intake.

Take a look at this thread if you haven't already

Top 5 L98 mods

 

Same thing here . I am not doing anything that I cant do myself in my garage . So basically bolt on parts . The most radical stuff I will be doing is a cam and possibly heads . I will keep you posted on anything I do .

Oh while I had the intake off, I will be porting and polishing my intake . You can see the details on that in this link.
https://www.thirdgen.org/forums/tpi/...ng-my-tpi.html