The Turbos are off the Vette...
The car has run great for the last couple of months with a TT Stage 1 but the back pressure on this kit was beginning to get to me .
Dyno numbers were disappointing ~400/450 and I hate stuff that doesn't work like it should.
The wastegates seem to be being forced open at WOT and boost is falling off over 4000 rpm.

I have been reading about some of your solutions to more power with this kit (Cams, Alky, and more boost) so I thought I'd take a slightly different approach and see if I could rework the T28s that come with the kit.
I called TEC to see what the options are and after a long chat it sounds like a T3 turbine is in the plan but they need the current turbos for matching and sizing.

There is so little room where the twins are mounted this may turn into a fitting nightmare and a total waste of time but I thought you all might be interested in how I get on.
Updates to follow...

 

The article I read about the TTi Stage 1 said that it was designed for 400-450 hp. Sounds like it is working fine.

The real solution to more power is the Stage X.

Good Luck,

Mark

 

What Jim will probalby do is turn them into Stage II Turbines. They also suffered from backpressure issues. One of the biggest gain you will find is in the A/R of the exhaust housing. If you lucky he has some .81/.82 or will do some port/machining to open them up.

Phil

 

FWIW, George had some .86 housings that we (Xtreme) tried on Shinobi's Z a year and a half ago. It pushed the boost ramp forward about 200RPM while not really changing rate of ramp and I think we picked up 20rwhp. Now, that being said... I took the .64 housings off and slapped on the .86's. No other changes were made. Now, if a different wheel is now being used along with some other massaging perhaps a bit more can be gained. George told me the .86's come from Japan and take quite some time to aquire if they are not in stock.

Keep in mind the info I offer is well over a year old.

Best of Luck
Bill

 

RoadRebel/Bill

The development of this kit is interesting stuff.
George's Web site talks about 600RWHP from the T2 flanged T3 turbine.

Were you involved? I wondered what the boost was and if the car was modified in any other way?

Since the next step taken by TT was to upgrade the manifold to a T3 flange for the Stage X, I'm guessing the backpressure mentioned was blamed on the T2 flange rather than the T3 turbine housing?

Are the Stage II turbos a direct bolt in?

As always great information
Thanks

 

 

Speaking from my own experience here...

OH YA , I was involved.

The custom T2 flanged T3/T4 hybrids did produce 593rwhp/709rwtq on race gas on Shinobi's Z. I have no other data because that is the only Stage2/3 kit I touched. When we started measuring back pressure on Rev1 of the T2 flanged T3/T4's it was over 45psi... through a .55 A/R exhaust housing. By rev 3 or 4 of that housing we were down to about a little more than half that. Those turbo's, when all was said and done, are/were not a bad setup at all. Coupled with the right CR and cam that kit IS a force to be reckoned with. I think, however, that Phil and George had already started working on the StageX when the Stage2, 3 or whatever you want to call it started shipping.
As far as the Stage X... I'd like to think that George and Phil wanted to support larger cubes if the customer so desired as well as getting away from extremely custom modified turbo's that cost a mint to make. George and Phil developed the Stage X without any involvement from myself or Xtreme Motorsports. They are the guys to discuss specifics with on that kit. The T2 flange and its limitations probably played a role in the decision making. But I remind folks that early on when LPE still had their T2 flanged cast iron parts they were producing VERY powerful 427 TT cars... typically 635rwhp and over 700rwtq... all with a 2yr 24k mile warranty. Add race gas and a boost controller and I saw 717rwhp and 841rwtq on an LPE 427 TT... through T2 flanges.

The "Stage II" (I think you are referring to an upgraded T28) and the T2 flanged T3/T4 turbo's both fit on the Stage1 T2 flanged manifolds. The T2 flanged T3/T4 turbo's required different down pipes...

Bill

 

I am interested in this too. I have a 3:1 ratio on backpressure with my stage 1 turbos. I also have a boost controller. My tuner has tuned around the backpressure issue on my stage 1.

I would love to have a better A/R on my turbos.

 

Maskell,

Take a look at the exhaust housing A/Rs..I bet you have .4x or .55s. and not the bigger ones...Take a look, it is a cast embossement on the turbine housing.

Phil

 

Bill

That is really encouraging!
As Mark said, (thanks bud! ) a Stage X would have been the right choice (and cheaper in the long run) but too late now...:o

From what you are saying Bill, I can upgrade this kit and see some pretty sound results. If a T2 flange works on a 427... I am probably going to be in good shape shooting for 550 to 600 at the wheels especially with the ECS alky to help out the Twin IC's.

Looks like I am going to end up with something like a Stage III built the hard way!
Such is my life

Hi ICULUKN, How are you? I figured one of us was going to start this ball rolling...I'll post the results,
TEC said they would turn around the turbos very quickly, but they seem insanely busy, so who knows...

 

Good luck Keep us posted. I was thinking of doing the same thing but I will let you spend the money and time I am plum worn out
I have pushed my Stage I over the past two years as far as I think it will go for now

 

King_Pin
I am beginning to understand where you are coming from , but you do have an impressive set up! They were some great numbers you posted.


Road Rebel

The numbers I wrote down were the TEC p/n 128 101286.
I believe that makes it a .86 AR compressor...

On the Turbine, the only numbers I found for sure were "381-24".
I may have also got "0.86 T694" from the turbine (but I am not absolutely sure about that one). Turbos shipped to TEC yesterday.

Any thoughts?

Dave

 

Phil mentioned that you can get the numbers off the turbo however I cannot clearly make out what the numbers are on mine. Also the two have totally different markings on them.

Can anyone tell?













Resized to make it easier to load and read.
Sorry about the pic quality as they were taken with my camera phone with bad lighting.

 

Vetteboy,
The pics you show are the T2 flanged T3/T4 hybrids... last I talked with Jim at TEC those particular turbo's were only going to come with a .55 A/R exhaust housing. The rear cover that is bolted to the exhaust housing is just a conversion cover... so one may utilize the exhaust housing as an internal waste gate setup. The last 4 pics show the cover only. You should see ".55" somewhere on the exhaust housing itself if I rememeber correctly.

Bill

 

Sorry - I wasn't trying to rub it in. The amount of power the Stage 1 is supposed to make was kinda an old topic that has been beaten to death.

The Stage I is definitely capable of making big power, as proved by king_pin, however, it requires a good turbo cam, heads, etc.

What is your goal for the car? Is the plan to modify the turbos and then toss a turbo friendly cam in ?

Mark

 

No problem, I thought this might be a well trod path for a few...I just missed those posts
My thoughts are; on a stock engine and 10psi that 500 at the wheels should be in the ball park (with ECS Alky to help out the twin IC's).

Heads and cam are next but I don't know what to expect (maybe 550-575ish?). My focus at the moment is to get the turbos upgraded so the engine can take advantage of the additional work.

Dave

 

Maskell,

I have a turbo grind that Phil reccomended with stock motor and 6.0 liter heads to lower the compression going in the car as we speak. The turbos that I have are the ones I posted above which Bill stated are the T2 flanged t3/4 hybrids. I cannot find anywhere it saying .55 or anything on them, but I would be interested in hearing what type of turbo that Jim decides to put on yours and the results from it as well. I will keep you posted on the results of my setup so you can guage what heads and cam would do for you.

 

Any updates yet?

 

Hi All

Thanks for your comments on the Stage III upgrade.

I called TEC and it looks like they are gettig ready to ship a T2/T3/T4 with a .55 AR turbine. Sounds like the same Stage III turbo but with a larger wheel in the turbine. (they were excited about the wheel size...)
No specs yet...
Anyone know what the wheel was in the original Stage III turbo?


I wondered if anyone could help with a description of the water cooling circuit for the TTi Stage III turbos?
I understand that the circuit is tied into the Heater Core circuit?
Is the turbo cooling circuit in parallel or series with the core?

Any other details you can pass on would be appreciated...

Thanks
Dave

 

Dave,
Parallel and Series
Yes, you can tap into the heater core circuit. You come off the supply side (going towards) of the heater core to feed the passanger turbo. Tie the passanger turbo in series with the driver turbo and then have the return off the driver turbo tie into the return for the heater core. Contact Mike or Chad at Xtreme or George at TTi. George fabbed me up some pretty nice aluminum "T's" for the coolant circuit. Xtreme should have a box of them laying around somehwere.

(edit) oh ya... the coolant ports on the turbo's are metric. Goodridge makes nice compact banjo style adaptor fittings to, say, -6AN... Mike probably has a few spares of those fittings too
Bill