Turbo Talk: TA-33C

[TurboRegal84]

I know there are several people out there running this turbo, and I would like to gather some information reguarding it.


I currently have a 33 on my car, and I can run 27psi of boost with the fuel supply and octane I use...I currently have the car tuned in so that if I hit 23 PSI in 3rd gear I constantly get an 02 of 802...Which is what I like.

What is the point on this turbo where you should stop cranking the boost up?

I am having a good deal of boost control problems with it. Spike is not the issue, but I cannot always get that desired 23psi of boost. If I am crusing along, and I plant the pedal to the floor I get 17 psi of boost, but if I slowly ease the pedal to the carpet I get the desired 22psi of boost that will sometimes fluctuate.

Do you think that the stock wastegate set up is not as efficiant with these larger turbos leading into the very restrictive 90 degree turn after the exhaust wheel?

Will upgrading to an external wastegate solve my problem?

I am looking to get a rock steady 23psi out of this 33 any tips or tricks from others would be helpful.

Thank you.

 

[GNeric]

When I first got my 33, I noticed it would overboost to about 29 psi in about 3 seconds. I finally got some help from another hotair guy here in town and reduced the orifice in the Y from .054" to .042" and now run a constant 21 on the street with 90 octane and 25 at the track with 108. This is with the wastegate arm set so it just about drops onto the flapper arm with very little tension.

You might want to email Cliff Wolff with this question. From what I understand, these are very efficient turbos and as long as you don't build too much heat, you should be able to keep it about where you are. He has compressor maps and all sorts of info. His email is cwolff@yahoo.com and he is a very sharp guy...EE at NMSU here. He has helped me a few times when I got stumped and I have been fixin' cars for 18 years now.

 

[mike85gn]

Ok, explain this to me. On the street, I get about 10psi out of my 33 before it starts to knock like crazy with respectable O2's on pump 92. WTF is wrong with this picture!?!? I used to run 17 psi on the stock turbo, is there really that much difference in airflow? Doesn't really matter, next Saturday (28th) I'm going to run it to the point of nuclear meltdown and crank the boost sky high on race gas and keep the O2's on the bleeding edge until I see bloody 12's! I'd just hate to have a fat turbo and run only 10psi on the street...

 

[mike85gn]

Oh sh!t!!! Maybe I should use an '87 MAF with my '87 computer! Whoops! Dammit!

 

[JayLashua]

Well, mike, I use a '84 maf on my '87 computer and I must say the mixture is a bit better for me, I got way too much KR with a '87 maf, I had two of them working perfectly, but boost was a difficult issue.. I keep my FP at 38 psi and I don't get any terrible amounts of knock with it at 15 psi on my '87 Turbo.

 

[TurboRegal84]

Mike...."Hi"! glad to see your still around!


What size injectors are you using?

I run a mixture of 97 Octane, and SMC alky kit all the time. If I run anything less then that 97 I get knock. As for differences in air flow between Turbos....YES BIG difference!

The stock Turbo flows in the 300-350 CFM range, and the TA-33C has reached such points of 700-750 CFM...The 33 is REALLY opened up if you place it next to the stocker. Along with the porting the blades are that out of a TA-49, so with the combination of a Large Wheel, and a small housing we can pump out a good amount of air.

The one downside to all that air is the heat it produces when it is being compressed into the intake. So to help rid the now compressed air of heat you use an intercooler (no thanks) or Alcohol/Water (Like GM intended our cars to be).


The reason some cars run better with the 84 MAF and the 87 ECM is because the 84 MAF has a tendency to richen the mixture, and this provents knock.

Nice hearing from you.

 

[mike85gn]

Hey Herb! Howz the Cowz? Anyway, I had my turbos flow'd and the stocker rang in a 393.7 cfm @ 15psi and the TA33 pushed 689.1 cfm @ 15psi (almost a 300 cfm increase!). I don't have the luxury of high octane gas until track time, right now I've got 91 octane (only one station on the other end of the city sells 94 octane ethanol-blended) and for track use I have 110 octane Turbo Blue. So that's almost a 20 point boost from my street gas to my race gas. You think I should be able to run about 20psi boost at the track on that if I run 12psi on the street? Thats 8 more psi for 19 more octane. Doable? Well, we'll see, or I'll be back here complaining about a broken motor!

FWIW, the turbo/FI shop I brought my equipment to said a TA33 (after they conducted the flow tests) will push the same amount of air at 8.5psi as the stocker will at 15!!! So I guess I'll tune for 10psi (approx. 460cfm, near the values for the stock '87 turbo @ 15psi) for now on my crap gas and get a little more perfomance than I got last year on the stock turbo and 15psi (because of the slight airflow increase and the cooler temps due to less pressure). At least it won't knock on 10 psi!

 

[mike85gn]

And what the hell happened to my post count! It used to be over 600! Oh well, better start contributing like 20 times a day as usual...

 

[Twins]

Nocooler check in here?

I've been chasing boost control for ......well I've owned this car 6 years. It's been really bad in the last 2 years as I've tried running an in car boost controller ( just a bleeder ) and tuner style.

Nocooler recently took my car for a fews days and along with numerous other things he set mine up like a 86-87. It uses a y and just one side of the wastegate sol. I do have a "high pressure" actuator from PTE that is a single vac line only style.

Now I have rock steady boost @ 15 psi that will spike to 17 for just a sec then settle to 15. Not even long enough for any knock and this is only from a 70 mph roll. In 1st, 2nd, and 3rd it stays put.

I run about 22 psi on 110 oct. and was under the belief that any more boost just causes heat and efficiency goes down quickly. Check with John C to find out for sure.

Are you still using the computer?, or tuner. I would love to see someone try an external. Again Nocooler had this on his 85 V2 maybe he can give some thoughts.

 

[TurboRegal84]

Twins from what I gather 22psi is the "efficancy limit" on the stock Turbo.


I just recently have been getting this car tuned in 100%, and I am slowly creaping the boost up on it I was at 15psi I jumped up to 17, and now I am at 22-23Psi so far with all that increasing of the boost I have felt a large difference in performance.

As for boost controller I have a Jim Testa Chip that is burnt for 18-19 psi, but recently I have just been using the adj. rod on the wastegate. With a healthy WOT stomp I get a consistant 22psi of boost with a slight fluctuation while boosting.

I was thinking about running an External wastegate, but I think our cars might be flowing a bit to much air for the Delta Gate. Anyone want to spend a few bucks and test the waters with a race gate?

 

[mike85gn]

Hmm, just got back from a test run w/11 psi. O2's around or just under .800 until 3rd, then they drop to .770. Knock in 3rd maxed out at 1.7º. This still on 91 octane. I want to try again with some 94 and maybe take it up a few psi and run KR-free. I think it's all in the gas right now, and there's not much I can do about it!