I have a 1988 Pontiac Trans Am GTA, T-Top, 305 TPI, 4 speeds automatic transmission, 3.27 rear, 115 600 miles, all original with no modifications at all, I did a full tune-up this summer too.

I have a little 100$ to spend right now. Can I buy some small mods on eBay or something like that? I did a 15.56 in the 1/4, if I could go low 15s for this year I would be happy.

Can I do 2-3 mods that will give me an overall boost at every RPM range?

Are the air foil and throttle body coolant bypass sold on eBay any good if I do both of them?

Other suggestions maybe?

I'm no mechanic so easy mods would be the best.

Thanks a lot guys for helping me out!

See ya!

 

Underdrive pulleys got mine from another member used for cheap.
You can do the TB bypass with a 99 cent connector from your local part store. Get some good air filters like a k&n.

 

How much HP and torque do you think I can get at the wheel with underdrive pulley, throttle body bypass and air foil?

 

Forgot to say my car is a daily drive except from october to april it's stored. Do underdrive pulleys will cause trouble in driveability? I heard somewhere it can cause some troubles or something

 

Well i have done alot of reading up on a few of these ideas that have been suggested to you. From what i'de read, an air foil is a useless waste of money. But you can pick one up off ebay for a total of $20.00. So i don't really see anything wrong with trying one for $20. Throttle body by pass is another supposedly worthless mod, but for the price af a 5/8" hose i'de try it anyways. I've "read" where the bypass will give you close to another 5 hp although i've never seen it documented on any dyno sheet. Did read a few posts of it causing idle issues,but very few. Underdrive pullies should not cause any problems ,i've been driving them with no problems for around 8 years now. Although you'll also need to get a new belt if you go with the pullies. Pullies,another subject i've read and heard the arguement you'll get no gains. What about upgrading your ignition box. I did see a dyno sheet in which after they intalled a MSD 6A ignition box they squeezed 3 hp out of it. K&N's is another good idea like not for sale said.

 

You do not want underdrive pulleys, especially on a daily driver. They are one of the most godawful things you can do to your car. Unless you would enjoy driving around, having your electronic equipment running at half power, headlights going dim at any stoplight, AC and wipers that run like a hamster were powering them. Forget having all of them on in the rain, radio/ac/wipers/lights. You're likely to burn out alternators like they were disposable lighters. I know from experience. I had them on my original 91 Trans Am, back in 1992. I cursed the worthless things for the short while I had them on before I got the 350 ZZ1 crate motor in and had those pulleys tossed in the trash.

Quite frankly though, you're working on the wrong end of the car. You really must do the exhaust first before you touch the top end. Your best bet would be to replace the muffler or cat, preferably a cat back system, but with only 100 bucks, maybe just a high flow cat will open things up.

 

To put the underdrive pulley belief to rest, I have the march system on my car, never had a charging problem. Only charging problem i have is forgetting to unplug the hood light at the carshows. If you have a weak battery or alternator then you will have a problem. But like most performance parts, they usually show the weak link in the system. Increase traction, you break an axle, put on a blower, the tranny goes, add a set of heads, you realize the compression is high enough to blow past the rings. Every performance part has its possible drawbacks. Like anything else if the system you are upgrading is not in sound condition, then dont expect it to last. When my battery died, i replaced it with a delco, when the alternator went I got a new one from GM. Never had a problem since I put the pulleys on.

 

I know people who have had the same charging problems with new alts and yellow top batteries. I'd get a larger I pipe and muffler used from somewhere.

 

I'd save the $100 you got and when you get enough buy a cat back system. You will enjoy that more and feel it more on the butt dyno. Better exhaust will wake up that TPI.

 

i would have to say the k&n and some good spark plugs and ignition parts, would be were i would start. then the muffler and exhaust. thats were i saw the most gain for my 305 tbi.I know that the engine combo's are diff, and u are starting off better,but i got 15.02 with that and smog delete stuff. thats just my opinion and my experiance, good luck.

 

An airfoil isn't going to get you more than 1hp I bet. I don't know anyone that felt a difference either. Throttle body bypass is alright. Underdrive won't do as much as a catback. And why even risk reliability issues? Maybe try to get an aluminum driveshaft? I have one and love it, no more vibrations at 80mph. Supposedly picks up an extra 1hp on the dyno and saves like 15 pounds.

 

WELL, IF IT WERE ME, I WOULD ADD JUST A TAD BIT MORE MONEY AND BUY A 3:73 REAR END. THAT SHOULD IMPROVE YOUR TRACK TIME. DON'T WORRY ABOUT ANY OTHER MOD RIGHT NOW. GET THE REAR END DONE TEST YOUR TRACK TIME, THEN MAYBE PURCHASE A STALL. NEXT GET A CHIP. A 305 IS A HECK OF A BEAST IF IT IS DONE RIGHT. PEOPLE MIGHT LAUGH AT YOU WHEN YOU TELL THEM THAT IT 'S A 305. BUT WITH A MILD CAM, PORTED AND POLISHED INTAKE, BETTER HEAD GASKET, CHIP UPGRADE, REAR END, MAYBE A STALL, REMOVE THE CAT AND GET A BETTER EXHAUST SYSTEM, THAT 305 WOULD GO LIKE BACHELOR OUT OF A MARRIED MANS WINDOW .

 

I wouldn't want 3.73s with a 700R4 unless you never see the highway- especially with these gas prices.

 

Thanks for the help guys!

I think I have set my mind... I think I will buy a performance muffler for now.

What's the original size of the exhaust system on a 88 GTA with a 305 TPI?

I mesured it fast, and from where my cat was (now it's a pipe) to near the muffler, it seem to be 2" 3/4. Where the pipe goes over the rear axle, the 2" 3/4 goes into a 2" 1/2 pipe that go in my actual muffler. The 2 exit pipes are 2" 1/2 also. Is it normal or it has been hacked? What was the original size of the exhaust on my car originally? From the factory, was it the same size from the front to the rear? I would like to put it back to stock size but with a performance muffler and no cat.

Thanks!

 

The exhaust forum knows this stuff. I believe it was 2.5" stock for a TPI. But a 3" performance I pipe with mandrel bends and a free flowing muffler will make a world of difference.

 

With a $100 I would say go out for a good dinner.

 

I will go ask around in the exhaust section.

So anyone else have suggestions on what to do with my small 100$?

 

Definitely do the exhaust! I have an '88 LB9 stickshift Iroc, and it gained over three tenths in the eighth mile, 9.98 @ 69.07 mph to 9.65 @ 72.34 mph by removing the stock cat that was near plugged (a hi flow 3" replacement would work fine if visual testing is done in your area) and replacing the stock original muffler with a higher flowing one, reused all the stock 2 1/2" intermediate pipe and tailpipes. That is with 3.08 gears in a hardtop car with all the goodies, power windows, AC, etc. Wieghs 3460# with me in it.

Oh yeah local shop charged me $124 to do the work, I used a Thunderbolt brand chambered muffler (Flowmaster copy)

If you had a Camaro I'd tell you to cut the baffles out of the airbox but 'birds have that air intake on the other side.

 

I have no cat right now so it should flow good...

But I don't understand why the pipe from the cat to my muffler is 2" 3/4. No one seem to know if it's the original size for a 88 GTA. I also noticed that right where the pipe goes over the rear end, a 2" 1/2 pipe is welded to it and goes into the muffler. The 2 exhaust pipes are 2" 1/2 too...

Which brand offer the least expensive performance muffler with 1 In and 2 Out with 2" 1/2 size? Anyway any performance muffler should be better than the cheap Canadian Tires muffler I have right now...

 

Buy some gas. You can never have too much of that.

 

I like Summit racing for stuff. Summitracing.com, you can shop by make, model and year of car. That way you know what will fit your application. They also have fast free shipping. Usually 2 to 3 days on instock stuff. Also check Ebay.

 

To wake up that Lb9, Get a shiftkit (45 bucks), Gut your airbox (however much a hacksaw cost), AFPR (70 bucks) Those 3 items would cut 2 tenths a second off your 1/4. If you really want to wake up your car, save up 700 bucks for some headers, y pipe and catback and expect to see high 14s.

 

save it and buy something worth while.

 

 

Okay, I will try to gather more cash in the 2 next weeks. If I get about 300$, will I be able to buy something(s) better?

 

Well if you have $300.00. Like most are telling you,start with the exhaust first. Then headers should be next.

 

A BECK"S if your 21

 

If you gotta do something I'm gonna second the motion for a shift kit. Instead of wasting it on small HP mods that will barely make a difference, I would try to better utilize what you already have. So something with the tranny or suspension, even rearend.

Maybe something else that won't be as much fun but is still important, maybe new brake pads all around or a fan switch for better cooling, stuff like that.

But I think the best thing to do would be to save the $$. In my experience you make the biggest difference when you come up with a plan and work towards it instead of doing cheap mods here and there with no goal or plan in mind. This was a mistake I made with my first thirdgen, ended up spending alot of $100-200 here and there with no plan or goal in mind and I got nowhere.

 

My suspension already been replaced last year but with like original parts. 4 coils springs and 4 shocks... For now it should be okay it stiff as hell.

For the rear end, I have a 9-bolts rear... Pretty hard to find a used set of gears for it! I have 3.27 right now, I'm looking for a set of 3.45. 3.73 would be overkill I think for my car right?

What is a good shift kit? Where is the best place to buy it?

 

trans go shift kit . I believe northern autoparts sells them at a good price

 

I don't think he'll be able to do the install himself. He said he's not too mechanically inclined.