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ajakeski
11-28-2011, 08:08 PM
Here are some photos of the VNT I rebuilt for a customer. He supplied this VNT turbo with a TII style compressor wheel and housing in place of the tiny one from the factory.
The vanes were frozen from what appeared to have been slag from a molten piston.
We got it all loose, but the turbine shaft needed replacement. It was sent to G-Pop shop for a balance. They also supplied a rebuild kit.
I's back together all except for the oil and coolant feed lines. Due to the larger compressor housing, the fittings going into the turbo need to be at a 30º-45º angle. A trip to the speed shop should fix that issue.
http://gallery.me.com/ajakeski/100340/IMG_0810/web.jpg?ver=13225242280001
http://gallery.me.com/ajakeski/100340/IMG_0814/web.jpg?ver=13225242130001
http://gallery.me.com/ajakeski/100340/IMG_0816/web.jpg?ver=13225243280001
http://gallery.me.com/ajakeski/100340/IMG_0818/web.jpg?ver=13225243490001
http://gallery.me.com/ajakeski/100340/IMG_0820/web.jpg?ver=13225243390001
http://gallery.me.com/ajakeski/100340/IMG_0819/web.jpg?ver=13225241660001
http://gallery.me.com/ajakeski/100340/IMG_0823/web.jpg?ver=13225242790001
http://gallery.me.com/ajakeski/100340/IMG_0824/web.jpg?ver=13225241830001
http://gallery.me.com/ajakeski/100340/IMG_0830/web.jpg?ver=13225242880001

zin
11-28-2011, 08:50 PM
How did he attach the TII cover?

Funny, the "correct" cover looks out of place next to a "normal" one!

Mike

BadAssPerformance
11-28-2011, 08:56 PM
Nice work! :thumb:

Vigo
11-28-2011, 09:01 PM
Similar to what i have for mine, but mine is a t04b compressor side.

The only real trick to it is finding that stupid adapter for the compressor backplate. You got a good source? I got lucky on mine.

cordes
11-29-2011, 12:20 AM
Thanks for sharing. That's pretty neat how that's done.

ajakeski
11-29-2011, 04:51 AM
I have no idea where the backplate came from. He brought the turbo to me with all these parts. I just rebuilt it.

Vigo
11-30-2011, 02:05 AM
If you could get him to reveal where he got it, and it's a repeatable, affordable kind of deal, it would do a great service to those out there trying to upgrade their VNTs. The turbine side can flow more than the compressor side can, so a compressor upgrade is one of the biggest things you can do to improve a vnt car (along with adding a wastegate).

zin
11-30-2011, 12:20 PM
A big +1 to that!

Seems like a VNT with a wastegate would almost be the best of both worlds, response via VNT and capacity via the wastegate...

Mike

cordes
12-01-2011, 01:42 AM
Are you guys talking about an external gate or an internal gate?

Vigo
12-01-2011, 03:39 AM
External gate. Although i personally plan to have mine coming straight off the turbine housing, similar to where the internal gate is on the other stock turbos.

ajakeski
12-01-2011, 09:37 PM
I'll get the info and pass it on.
As far as I know he bought the turbo this way form someone.
Maybe even someone on this forum...

Under pressure
12-21-2011, 02:04 PM
subscribing...

Directconnection
12-21-2011, 06:15 PM
The turbine side can flow more than the compressor side can, so a compressor upgrade is one of the biggest things you can do to improve a vnt car (along with adding a wastegate).

If a stock VNT has trouble trying to slow down and control boost, how will it handle a compressor that will be spinning at even less rpms per same psi?

Pat
12-21-2011, 08:33 PM
If a stock VNT has trouble trying to slow down and control boost, how will it handle a compressor that will be spinning at even less rpms per same psi?

+1

I don't think the compressor is the problem here.

Under pressure
12-22-2011, 02:42 PM
I am pretty sure the tiny vnt compressor ...heating up the intake charge spinning so fast , actually is worse than the exhaust turbine's restriction, Ive checked into a t28 wheel for my t25VNT, turbine clipping also , But I dig the T2 compressor Idea also !! cool

turbovanman²
12-22-2011, 03:15 PM
Subscribed.

Pat
12-22-2011, 05:48 PM
I am pretty sure the tiny vnt compressor ...heating up the intake charge spinning so fast , actually is worse than the exhaust turbine's restriction, Ive checked into a t28 wheel for my t25VNT, turbine clipping also , But I dig the T2 compressor Idea also !! cool

My concern is simly that if the vanes in the turbine are not able to control boost creep/overboosting on a decent flowing engine with the stock compressor, it's only going to be worse with a larger compressor. I agree that tiny compressor is heating the hell out of the charge and likely well past it's efficiency range, but like any turbo, the exhaust side needs to be a good match to the compressor side.

Being a new VNT owner myself, my actual VNT experience is next to nothing and most of what I'm basing my opinions on is heresay at best. I'm very much looking forward to seeing how this all works out. Keep us posted!

Directconnection
12-22-2011, 06:06 PM
A 5digits mod that I never did on mine, is to notch the vane's lever arm that the actuator hooks to. Notching it will let the vanes open up a tad more... for a lower minimum obtainable boostage.

zin
12-22-2011, 06:09 PM
The turbine concern is valid past a certain point, which is why Vigo and myself would add an external wastegate, then you should have the best of both worlds, quick spool via the VNT portion, and control via the separate wastegate.

Mike

Under pressure
12-22-2011, 10:03 PM
as far as my limited VNT experience has been , freeing up the exhaust with a fabbed 2.5" catback and a magnaflow has changed the boost charicteristics in my '90 Daytona Shelby from 7-8 to 15+ psi at the higher rpm range. I run 1 step cooler spark plugs with stock timing and a stock engine and cat converter. It was a huge improvement... to a point , it is my bad azz commuter car.

After a years worth of driving + running into overboost occasionally , I eventually pushed the headgasket out and I am pulling it down to freshen and improve after Christmas.

I talked today with GPOP Shop about sending in my T25VNT as now is a perfect time. They offer a T28 compressor wheel retrofit and turbine wheel clip and etc. GPOP guy said that although the compressor wouldn't slow down the turbo shaft speed much , discharge temps would be lower , and the turbine clip would improve the restrictive exhaust housing. There seems to be a few alternatives out there now !

Question about the hybrid in this thread is, Will the large compressor wheel be too large for the bearings and the shaft ? durability wise ?

Do any of you guys have an external gate build in process ? Is it as simple as drilling and tapping the exhaust manifold for a fitting and adding the 'gate ? (is there room?)

My only other Turbo Dodge was an '89 T2 and that was easy to set up to run 14 psi and be reliable. That is my goal with my Daytona VNT. Keep me in mind ! I'll do what I can to help figure out a solution as I am about to be tearing it down soon.


-Dennis

Directconnection
12-22-2011, 11:04 PM
Your '90 VNT Daytona should be making 12psi stock, not 7-8. Both of mine did 12 psi, and the cal I had was a shade under 15psi. When I ran a full 3" exhaust w/no cat I got 17psi in 4th with that cal, but 15psi in 1st-3rd.

I'm a believer that the VNT can be upgraded... it's just that 99% of those out that that tried, failed. Maybe the stock T-II compressor wheel will be pretty good as the ones I've heard about used a S60 and S70 style wheel. Maybe some proper porting in the turbine housing could improve things some...

Another important upgrade is the intercooler. 5D always told me to ditch the stock T-IV cooler and run a S60. I wish I had done so.... as a close friend found almost 20whp between a stock T-II vs TIV cooler on a S60 2.2 at 20 psi.

cordes
12-23-2011, 02:11 AM
Great point about the VNT cooler Steve. They have only 9 rows vs. the TII cooler's 10. They are a slightly taller cooler, and that probably worsens flow even more. A S60 cooler is a super idea for a VNT IMO, and even a TII IC would be a huge upgrade I bet.

I would love to see someone run "fast" in a VNT powered car. It'll take a lot of dedication though, especially in the face of the ease of a TII or S60 swap which will yield way better results with virtually no effort.

Under pressure
12-23-2011, 11:41 AM
To avoid getting off topic , my car ran poorly when I bought it , out of tune and rotted exhaust. To explain my skewed Boost data. The first things I did were a new fuel system , exhaust , and tune up and timing belt. All stock and only a catback and running right , it sees the 15+ now

Anyone out there with a s60 intercooler pm me please.

Unless this T2 compressor hybrid works great , I'm seriously considering Gpop's mods to my turbo. Maybe they have info on the mysterious backing plate ?

zin
12-23-2011, 12:32 PM
Still no word on the super secret backing plate that made this mod possible?...

Mike

turbovanman²
12-23-2011, 01:54 PM
What about using a TII cooler? Don't they work better for a street car?

5DIGITS
12-23-2011, 01:57 PM
Your '90 VNT Daytona should be making 12psi stock, not 7-8. Both of mine did 12 psi, and the cal I had was a shade under 15psi. When I ran a full 3" exhaust w/no cat I got 17psi in 4th with that cal, but 15psi in 1st-3rd. I'm a believer that the VNT can be upgraded... it's just that 99% of those out that that tried, failed. Maybe the stock T-II compressor wheel will be pretty good as the ones I've heard about used a S60 and S70 style wheel. Maybe some proper porting in the turbine housing could improve things some...

Another important upgrade is the intercooler. 5D always told me to ditch the stock T-IV cooler and run a S60. I wish I had done so.... as a close friend found almost 20whp between a stock T-II vs TIV cooler on a S60 2.2 at 20 psi.

This is all painfully true.
Improving the flow and efficiency on the compressor side is compounding the problem unless something is done to correct the turbine issue.
In short, the turbo was intended for a 1.6-1.9L engine and the higher exhaust volume/velocities from a 2.2. push it over the edge - it's a poor match, as is.
Address the exhaust (shimming, spacing, added wastegate, etc..) then compressor mods will produce a benefit rather than surge and over-boost.