80 turbo TA Mods

Has any one done any mild mods to this car? I am going to run straight pipes. But need to know about cams and rocker arms. I have read that only rocker arms and exhaust will help unless I want to do major things. :runaround:Will headers with the the turbo help??

well, your compression is about 7.5:1, and from what i remember they run about 9psi of boost, which you can get away with as high as 10:1 compression with proper pistons. you could attempt to raise the boost pressure (not sure how to go about that)

other than that.....
turbo back exhaust system
ported and polished heads
milodon megaflo valves
anti friction coatings
thermal reflective coatings
aftermarket camshaft (not sure who has it, probly comp cams)
upgraded ignition system to light the fire better

not really sure outside of that. unless you want to ditch the factory turbo, and see if you can find some aftermarket pistons and whatnot.

Careful! The Turbo T/A was the first GM car with a "knock sensor". It can and does retard the timing when detonation begins. Raising the compression is a bit risky due to this. Keep it at 9:1 and no higher. That will require a minimum of 93 octane fuel. 350 Chevy "dished" pistons work quite well for this.

We use the Comp XE250H grind with the LSA changed to 114. This is a "custom" grind, but the only issue there is time. The price is the same as the catelog grind.

The head work described above is a good thing for most any performance application. There are more modern and less expensive valve and spring combinations.

Headers won't work with the turbo. The plumbing requires the manifolds to put the exhaust gasses into the driven side of the turbo. "Custom" pipe work would look cool, but I doubt there would be much power gain over the factory maifolding. Pontiac was always pretty good about the manifold stuff.

Cliff's High Performance in Mt. Vernon, Ohio has the hot lick on carb work. Nobody does Q-Jets better...

Jim

I believe the turbo TAs are based on a pontiac 301. I'm not sure SBC parts will work in it.

it is baised on the pontiac 301, but it is also a 4in bore.... if the wrist pins are the same size... dont see why sbc pistons wouldnt work........

I found these specs for 301 turbo pistons. How do they compare to sbc?

V8-301
4.9L
4.000(IN)
101.6(MM)

PONTIAC
ENGINE

1980-81

7.5

LU8 engine, turbo. Singles from the Factory only.

APPROXIMATE HEAD VOLUME=13.5cc

Comp. Ht. 1.570
Pin Dia..9273 Offset

1531LR
STD.
.020
.030
.040
.060

2-5/64
1-3/16

Shallow
Groove

10013653(R)
10013659(L)

10013632
10013640

http://webpages.charter.net/beckracing/disoval3.gif

looks the same, bore, compression height, piston pin diameter, all the same as a sbc.

True enough, 301 is a "baby" Pontiac (please don't refer to it as a REAL Pontiac...), not a Chevy, but... The engine neither knows nor cares what the parts are designed for if they fit! A piston is a piston is a piston...

The "dish" is the difference between the standard 301 and the turbo. The turbo-specific pistons are quite difficult to come by. We (engine builders) often find ourselves in a position like this where a little "creative" thinking is called for. We cruise the catelogs (most information not found "on line" or in data bases) looking at parameters that are "close" to what we're working with. A little here, a little there... Viola! If the compression distance (pin height) is close, a minor amount of block decking is no big deal. Neither is "trimming" a bit off the head of the piston if too high. The 350 Chevy pistons are listed as 1.550" for the cast ones, 1.563" for the forgings. I like the idea of a forged piston in there! Speed Pro part number L2304NF-xxx (where xxx = oversize).

The two weakest "links" in the 301 "chain" are the crank itself (tiny little thing, no counterweights, BIG main bearings...) and the cast rods.

Jim

p.s. Unless I qualify my answer as an "opinion", you can take it to the bank. I do this stuff every day.

I am looking to just buy things off the shelf and install them. I don't want to special order parts or machine any parts. I plan to buy 1.65 crane rocker arms. What would I need to buy in addition to that? Will this fit with the stock valves and springs? I really don't know much about modifying engines.

My good friend just got his ASE cerification and he does not know much about specs and numbers. He just knows how to change things out. So that is what I am trying to do. Just buy things that are available and change them. I just don't know the combinations of things.

Pretend this is your's and what would you exactly do given the limitations of the things that you purchased. And what order would you do them in? Remember NO special order parts or machine shops involved. I just need simple engine recipes. :popcorn:

p.s.- rebuilding the 800 cfm rochester quad jet

you can make the car pretty fast without getting into the motor. Number one you should start with exhaust. the larger the exhaust the faster your turbo will spool and the more effective the boost will be. you may even gain a psi or two. this alone will make a big difference. With that low compression you can probably raise the boost a bit too. Theres tons of room for growth without getting into the engine. i'd do some research on the car and check out other ppls builds. this will let you know what you need to do what, but i'm familiar with many turbo setups and theres plenty of room to grow with just simple bolt ons.

The 1.65:1 rockers will add 10% lift and about 2 degrees (@.050" lift) duration to the cam. The heads will require the pushrod holes to be "laid back" about 1/8" to avoid binding. That would require removal of the heads. Comp Magnums are better quality rockers than Crane "Golds" and Scorpion or Harland Sharpe rockers are FAR better, for less money. We've had a lot of grief from Crane rockers. Don't EVEN consider those "extruded" aluminum ones (I think they call them "Energizer"). Stock valve springs will be very near coil bind with the higher ratio rockers, as well.

There are no "off the shelf" parts for 301 except stock replacement. If it were mine, I would drive the car and be happy with it, unless you are going to "do" the engine.

Sorry, dude, there's simply no "free lunch". If you follow the advice of "checking out other ppl's builds", you will find very little information, as no one "builds" 301s. I'm a "national level" Pontiac shop, and we've had two in the last five years, both "numbers match" restorations, no modifications. I haven't "pumped one up" in over 10 years, and the results were nothing to write home about...

Contact Cliff's High Performance in Mt. Vernon, Ohio, for the Q-Jet work. He's the best on the planet. Pontiacs are HIS thing, too....

Jim

Since the 301 is the only smallblock Pontiac ever made and was made for such a short period of time and was such an underpowered engine, there is going to be little to no aftermarket support for it.
If you are wanting more power and want to scare the crap out of someone, get a 455 HO engine and slip that in there..The first person you're going to scare is yourself

You guys just don't know about boost. I say do the exhaust with some thicker diameter stuff. feel free to go big cause a turbo application. 3" would be a good size. You'll feel that turbo spool faster and you'll be making up some hp.. Don't let these guys talk you out of it. they probably don't know much about turbo setups and applications. Boost is better then displacement. although it's a nice when you have both. With that low ass compression you have a lot of room to make power.

dont forget to feed more fuel as you go up with boost, cuz a lean turbo is a broken turbo

Well who knows the car may already run rich naturally. Theres tons of ways to regulate fuel mixture though. These cars have computers in them right? are these cars fuel injected? either way, theres a way to tune fuel and timing. i'm telling you this car can be fast you don't have to swap out the motor.

There is NO replacement for cubic inch displacement, even forced induction. With the puny 301 he may make some higher HP numbers tinkering with the turbo, but with a 2nd gen what he needs is torque and a turbo ain't gonna give you that.

you can make torque with a turbo setup. look at the third gen turbo ta. thats a 3.8 turbo and it makes 345ft lbs on low boost. just think grand nationals and turbo trans ams. those cars are sick as hell. only reason why these particular turbo trans am gets the bad rap is because back then they really didn't know much about turbo's or boost. fast forward 10yrs to 1989-1990 and they figured it out. in 1980 they were faced with strict emissions and cars with no balls. we are talking v8's here that were making 145hp lol So they turned to boost to up the power. A common issue with the 2nd gen turbo ta is knocking from detonation. even in stock form. so retard the timing, run higher octane gas and turn up the boost 5psi..

Guys,

No reason to argue over all this. Turbos were understood just fine, as far back as the 1920s. Offys were tearing up race tracks with over 500 HP in 1925.

Turbo T/As were a "stop-gap" design, intended to produce nearly the same power from 5 lrs. as 6. The comments about the 455 HO are right on the money. NO turbo car makes the onrush of power like a big-cubed, long stroke V8. 345 lb. ft.? That's little more than 1/2 what a good 7.5 lr. engine makes without an adder.

One of the current "quickest Pontiacs in the world" is John Welter's 440 CID ProMod, running a BIG turbo. The car has been 6.82 @ 205. Not bad for an old Injun "door slammer". This is a Pontiac V8, not a Chevy with Pontiac covers. THE quickest Pontiac in history is a 399 CID version of an old 389, with Mickey Thompson "hemi" heads on nitro with a "Roots" type blower in an old slingshot (Good Guys competitor). It's been 6.77, but had to shut the fuel off at the 1,000' mark. Top end speed was only 201 (coasting through). Look for all this to change this year at Pontiacs In The Park. Several TA/FC and ProMod projects are finally ready to make their debuts. 5s could be in the "cards".

Comparing GNXs and '89 Turbo T/As to '80 Turbo cars is like comparing the '06 GTO to the '74. Not a fair assessment. Fuel injected and computer controlled versus carb a knock sensor. Apples-to-donuts.

Jim

Yea they are fairly different setups, but i still believe you can pull out some good power from the 80ta. I'm sure it may have it's limittations cause of design or what have you. I did some reading on the car from wikapidia, and i guess they are said to have weak internals. But even with that said i'm sure the motor can hold another 50whp. thats not very much. I guess it comes down to how serious someone wants to get with that 301. anything can be rebuilt and become stronger. I just think that not many had too much interest in modding the car so it really just got a bad label. You can make anything fast.

i have to diagree in one area though. sure turbo's have been around a while, but we certainly have a better understanding of them today. i mean today we have methods of tuning that were not even thought of yrs ago. there was no way we could have been efficent back in the day with turbo's...

I see things from a completely different view. you guys kinda prefer a big huge engine instead of boosting a smaller one. My friends have 4 bangers that are boosted. With 4 bangers and small cars you can't fit a huge engine in it. so we are limmitted to how much engine we can run, so we are left with boosting. And it's very effective, there are 4 cylinder motors that can hold 800+ hp. So when i hear about a turbo v6 or v8 i instantly think potential.