Recently I have concidered the possibility of turbocharging my 305 Iroc, but the problem is money. A good turbo kit will run be well into the $2000 range, and I cant afford that. However, I was wondering if anybody knows about possibly swapping in the turbo unit from the 1980-81 Pontiac Turbo Trans Am, since the trans am had a 301ci engine, a mere 4 ci smaller than the 305. Is such a procedure possible? I hear that the turbo overpowered the 301 and frequently caused problems, however the 305 has to be built better than that. I figure if it is, im sure a junkyard wouldnt mind selling that equipment to me for practically nothing if I can find one of those wrecked birds. Can it be done? Does anyone know of anyone who has tried?

 

this is great question!
why use old outdated technology that didn't work from the factory?

 

In the wonderful game of low-budget speed, I dont care how old the unit is, I just want something to make some horsepower without the hit to the wallet. Im just wondering if that particular setup is even possible, giving that the 301 was a 4 barrel (I think) and the 305 is TPI...dont know if that poses problems)

 

It's a lot harder than you think. first off, the TTA was a 6 cylinder. you have to think about things like compression, intercoolers (about $900), computer controlls (about $600), custom headers/exhaust/downpip/intake, i also believe the TTA was a 3.8 liter not anywhere near a 5.0, but it could have been the 4.1 i really doubt it though

 

secondly, the TTA was in no way overpowered by its turbo. The 3.8 was built for a turbo. the 305 wasnt. The 305 would probably need quite a few mods to be optimized for the turbo setup. Like heads, and a cam (the cam is really needed for a longer exhaust duration I believe)
If you were to find a TTA in a junkyard. Which I would be damned surprised if you did. It would cost you a fortune to get anything off of it. They are a famed beast nowadays and they were a very limited production car. The chances of finding one that the owner doesnt know about is small too because they all have their # on the dash

 

This guy wasn't talking about the 89 tta's he was talking about the 80-81 second gens that were turbo'd. I thought it was a 301 also or something odd. Not a common displacement. But I thought about the 89 turbo for my 5.0. I know the intercooler would bolt right up but the turbo and cam and heads might be a *****.

 

The only part you would be able to use is the turbo itself. Forget about the exhaust and the intake, thats trying to mix a Pontiac engine and a Chevy engine into one, and that is not going to work.

 

whats so bad about a TTA?
i want one damnit

 

madmax is correct. The only thing usable would be the turbo, so what chance of that would you be able to find one, and in restorable condition? Technology has made quite a number of gains in the way turbos are made these days so it would be more beneficial to look for one from a later model year like a T-Bird for example. You really don't need/want one with higher boost than 8-psi, unless you want to go for an intercooler. When dealing with 10psi or more, things start to become complicated which means more hardware which relies on more $$$. Your budget will dictate how much boost you can afford to have!

 

You need to check out the information posted by Andris Skulte, of Skulte Performance Designs. He created a twin turbo project from scratch for his 305 powered Camaro Z28. However, he soon discovered that his Camaro was in fact a 350 powered Z28. (lucky him!)

Madmax is correct in that the only portion of the turbocharged 1981 Trans Am is the turbo itself. The '81 turbo Trans Am was a carburated Pontiac 301 that made a shade over 200 horsepower. It is a mid-16 second car in the quarter mile. I suspect that you would find the turbo to be quite inefficient in its compressor design, resulting in very high temperatures in the compressed air. You would have to custom fabricate everything from the induction piping, to the accessory brackets, to the exhaust.

The cost of the actual turbo will be only a small amount of the actual cost of conversion. I think Andris spent $5K or so on brewing his own system, and he even did most of the TIG welding himself!

See: http://www.skulte.com for more details.

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Daniel Burk
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My opinion on this subject (turbos or blower)fabrication work is no easy task which takes skill money and experience.Paxton and vortech make applications for almost any tpi application.BTW saw a turbo ta 81 setting in at a junkyard the other day.I think that they are the same turbos used on early regals and montes.

 

First, Wasn't the 301 a V8? A 3.8 is only 232 ci. Second switching from a carb setup to TPI is the easiest thing ever. Carbs have to run in vaccuum that's the only way they work, so you have to modify the bowls and floats and etc. On a TPI car all you have to do is seal the comp out to the throttle body and your done. What could be easier? The damn exhaust maniflolds might even bolt up. If you want to run an intercooler it gets a little more complicated, but as far as I know I don't think the 301's were intercooled. I say go for it. As long as you don't overboost max out the injectors and burn up the engine it should be fine.

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'89 Red Formula 350- 350 .060 over forged pistons 232* @ .020 cam Performer RPM Holley 750 DP Vortec 1.94 1.50 Accel Coil and dist. Hedman shorty headers Dual Exhaust w/ cutouts 1LE WS6 suspension, wheels, and brakes, 9 Bolt 3.27 Posi Edelbrock LCA's & Track bar subframe connectors 700R4 Harwood snorkel scoop Eclipse Head Unit Delco Bose Speakers 2 12" Pioneer subs w/ 400 watt/chanel amp

 

Hey MYCARSUCKS... I believe 305IROCZ28 was refering to the 1980-1981 TTA.

Hey 305IrocZ28, If you get the model number of the turbo and the EXACT trim (compressor wheel and housing, turbine wheel and housing), either I or someone else on this board can research it and see the map for it and tell you if the turbo can work on a 305.

The turbo caused major problems on the 301 because the 301 was just plain JUNK!!! Pontiacs futile attempt at a "small block" was VERY UNSUCCESSFUL. I believe that this engine was the reason they stopped making V8's period, let alone the fact that NO ONE ELSE in the GM corporation could build a V8 like Chevy!!!

 

True, but look @ the period of time, what was not junk during that period of time?

NOT

No argument here.

BW

 

My personal opinion: I don't think it would be that hard. I would not however use the turbo from the Fire****. I would use 2 from a Turbo Coupe 82-86 would be best. 87-88 were a little smaller. The 82-86 were T03's, the 87-88 were smaller Ishi Turbos. 2 of the T03 and an intercooler would kickass. It is more fabrication, but in a sense, all power adders have some fab. work needed. Hot Rod did a special on wagons. One car had 2 T03, a Holley, on a 460 that made 700lb.tq. and 355hp. This was a stock motor with no IC, and he added 2 turbos. These turbos can be picked up at juckyards across the nation for $50. A good Spearco IC is about $1000, and then all the fab work. You could get 2 IC from an 87-88 Turbo Coupe, and weld them together, that would set you back about $50 plus welding, and would work just fine. I pushed 22psi on my old Turbo Coupe with out fail. These work real well. If you get new turbos, I would go for 2 T3/4 hybrid turbos. These will run about $700 each. (Junkyard looks even better). Just an idea........



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Joshua Johnston
1991 Z-28
Flowmaster
K&N
305 / 5spd. (Temporary)

 

ok...FORGET THE 301 TURBO...complete JUNK. There is a guy named Preston Smith(forget his IM name...can anyone help??) who has a turbo'ed 305 running impressive times...i think he's running a T76 turbo. I was gonna turbo my L98 but i'm opting for another way..i have a GN drivetrain lined up for CHEAP...so since i can't afford an 89 TTA i'm making my own....turbos if properly setup will beat any blower...good luck

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Tony

 

The turbo may be junk, but the flanges and tubing are as good as gold in my eyes. That's a whole bunch of fab work that can be avoided. I'm not up on my 301 trivia, but if anything even closely related to small block geometry then the down pipe, manifold pipes and flanges, comp pipes(even if the don't fit goo because of the carb), IC pipes(if the exist), will make life a lot easier. Most people don't have pipe benders or flange cutters in their garage. I work on turbo engines for a living so I know a little about this.

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'89 Red Formula 350- 350 .060 over forged pistons 232* @ .020 cam Performer RPM Holley 750 DP Vortec 1.94 1.50 Accel Coil and dist. Hedman shorty headers Dual Exhaust w/ cutouts 1LE WS6 suspension, wheels, and brakes, 9 Bolt 3.27 Posi Edelbrock LCA's & Track bar subframe connectors 700R4 Harwood snorkel scoop Eclipse Head Unit Delco Bose Speakers 2 12" Pioneer subs w/ 400 watt/chanel amp

 

Didnt you read what I said?

The 301 is a PONTIAC motor, its nothing like a small block Chevy and none of the parts that mount to the engine itself will fit. You want the flange? You'll have to cut the cast iron manifold apart to save that piece and weld it to a Chevy manifold.

And BTW the Pontiac engines were alot better than any Chevy engine I have ever seen. Reason production stopped was it was more costly to build and GM only wanted one set of engines for all cars, no more Buick, Cadillac, Chevrolet, Pontiac, GMC, Oldsmobile, etc etc motors, just one 'corporate' motor for all cars. They didnt quite make it, but quite a few 'brand' engines died from that.

[This message has been edited by madmax (edited July 19, 2001).]

 

B F'N Shiet!
the ONLY reason GM continued with the Chevys and not the Pontiac v8s is because Chevys had them in millions of trucks and Pontiac and all other GM companys went FWD in their vehicles.

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-Tas
'89 Formula WS-6

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To be installed eventually far far far into the future: Yours if the price is right and I don't have to ship :
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Super GRK_Taz World
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There's a lot of truth to what you say Madmax. Pontiac 400s, while having the same bore and stroke as a SBC, had a taller deck allowing it to run much longer rods than you can in a SBC. The deck was so tall that the 400 was able to be stroked to the 455...which can be quite the torque monster.

And if you remember back into the early 60s, the Super Duty Pontiacs were cleaning up both at Nascar and NHRA. What killed Pontiac as the "Performance Division" was GM's decision to stop all corporate racing.

And for those who know their Pontiac engines, Pontiacs were a "one block family"...going back to their original V8 (267 c.i. IIRC) in 1955.

Another great motor is the Olds 455s. In fact, one of the WORST motors in the late 70s - early 80s according to the various consumer reports was the SBCs due to their camshaft problems. I know plenty of people that had to prematurely rebuild their SBC at that time because the cam wore out and caused the lifter to "rock" in the lifter bore. So if you even replaced the cam and lifters (but forgot to rebore the lifter bore), your new cam would wear out really quick.

This is when many consumers discovered that their Olds/Pontiac/Buick DID NOT have a BOP engine but a SBC and GM was sued. (Even some Cadillacs got a Olds 350 disguised as a Cadillac motor). That is when GM went to the "corporate engine" policy of "any divisions engine" was now a "GM engine" and fair game to be installed in any GM car.

 

So what does the Turbo configuration look like on this engine? Is it like a V6 with the turbo mounted in the valley or is the Turbo mounted off of one manifold with a crossover tube from the other manifold?

 

The turbo sits on top of the manifold just offset of the carb(to the right).The set up is like the 84-85 buick gn.A local guy has a rebuilt 301 and turbo ready to go.
Turbos and carbs not good combos if you ask me 8lbs max till the carb blows

 

The 1978 Pontiac brochure I picked up at the dealer included a loose sheet that on some was attached to the first page, it was a disclaimer listing the different engines used in Pontiacs that year.

 

I went to mypartshop.com and searched for the intake manifold for the 81 turbo 4.9 and it came up with 3 places that says they have them so if you want one to look at email them and ask the price like I am. Also I will see if they will send a pic of it.

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91 z-28 305 700R4
3.73 gears out back
T-Tops and Black all over.

 

I bet they don't make one for mine!



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'92 Astro 350 TBI Edelbrock intake, MSD 6AL, 3.23's, dual electric fans, 2.5" exhaust, Dynomax muffler, B&M 2nd stage shift kit, 255 60 R15 tires on AR-727's

 

No offense to anyone but...

I personally dont like ANY of the BOP engines that ANY of the "other" corporations built, excluding Cadillac. Why? Well...

Yeah they made good power but Oldmobile engines had CRAP for oiling systems...

Pontiacs WEIGHED TOO DAMN MUCH... and most of the Poncho engine cars I see are SUPER SLOW for all the noise they make, and they sound like sh*t...

Buicks were nice, but they didnt stay together long if you revved them high...

AND ALL OF THEM WILL COST WAY MORE TO BUILD THAN ANY SMALL BLOCK OR BIG BLOCK!

Just my opinion though. No offense to their fans though.

If there were no more Chevrolet engines left to build and I just had to build something, I'd build a Cadillac engine.

And before I get flamed to death, how many of those NMCA Super Street, Pro Street, or Outlaw Street racers are using anything other than a Hemi, BBC, SBC, SVO Ford, or a Olds DRCE engine (which happens to be based on a Big Block Chevy)?

 

This is what I was talking about. If it's set up like this then you can keep the up pipes(which are just like exhaust tubing except they have heat expansion sections) that go from the manifold to the turbine. Maybe some of the turbo mounting hardware. and the comp out flanges and maybe some of the tubing. This will save a whole bunch of fabrication time and money. Exhaust shops can weld pipe together, but they can't make flanges.

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'89 Red Formula 350- 350 .060 over forged pistons 232* @ .020 cam Performer RPM Holley 750 DP Vortec 1.94 1.50 Accel Coil and dist. Hedman shorty headers Dual Exhaust w/ cutouts 1LE WS6 suspension, wheels, and brakes, 9 Bolt 3.27 Posi Edelbrock LCA's & Track bar subframe connectors 700R4 Harwood snorkel scoop Eclipse Head Unit Delco Bose Speakers 2 12" Pioneer subs w/ 400 watt/chanel amp