[TransAm 474]

Ok, thanks Tom, so what size wastegate(s) would you choose to run on this application, and where would you place them in the system? I was first thinking of doing just one big gate right at the turbine inlet, but I never thought about it being a divided inlet, so with the billet divided flange that I had posted above that has the 2 1/4" stubs in it, there is nowhere to install a wastegate to be able to control both pipes if I just simply run one pipe off each head and into the turbine without merging them anywhere. I have seen others use a merge right at the turbine,that both head pipes run in to, and they place their gate in that merge, but that way it is no longer divided when entering the turbine, but maybe it doesn't necessarily mean anything? Like I said, I'm a novice at this Lol... I really appreciate your expertise Tom.

[Tom Vaught]

Think about it for a minute. Turbine Housings can be classified as single scroll and twin scroll. This refers to the number of passages that make up the volute. Generally, two scrolls will help spool up a charger quicker under low to medium RPM range. The benefits decrease with higher rpm.

Having a intake manifold with a part of the center divider cut away still allows the air to flow to the different passages in the intake. Especially at higher gas speeds.

A Turbine Housing with a split scroll inlet feeds the wheel with two high velocity nozzles
pushing against the single turbine wheel from two different high velocity "nozzles".

The Nozzles are after the turbine inlet.

Say you take two inlet pipes and weld then together so you had two inlet pipes with a T-6 flange mount on the end.
Then, you cut a round hole section on the roof of the pipes and installed a wastegate flange mount there), the exhaust flow would 99% of the time be traveling thru the pipes, the waste gate would be closed, and the exhaust flow would not pass thru the wastegate.

When you have a given boost pressure the wastegate would start to rob a portion of the exhaust from each pipe but the majority would still be driving both sides of the Twin Scroll turbine wheel.

At some point if the wastegate were large enough, it would divert enough exhaust flow for the turbo to maintain a given boost pressure.

You are not robbing exhaust flow from the turbo making "X amount of Boost", you are removing EXCESS exhaust flow to maintain a given "X amount of Boost" Pressure.

A 45mm wastegate should allow "control" if you are not running 40 psi of boost.

People run dual wastegates because the turbos are typically some distance apart.
Connecting a long pipe between the turbos to a single gate would be a poor design.
That is not the case with your single turbo installation.

I tried to find a picture on the web but had no luck on a quick look.

Tom V.

[TransAm 474]

Originally Posted by Tom Vaught

Think about it for a minute. Turbine Housings can be classified as single scroll and twin scroll. This refers to the number of passages that make up the volute. Generally, two scrolls will help spool up a charger quicker under low to medium RPM range. The benefits decrease with higher rpm.

Having a intake manifold with a part of the center divider cut away still allows the air to flow to the different passages in the intake. Especially at higher gas speeds.

A Turbine Housing with a split scroll inlet feeds the wheel with two high velocity nozzles
pushing against the single turbine wheel from two different high velocity "nozzles".

The Nozzles are after the turbine inlet.

Say you take two inlet pipes and weld then together so you had two inlet pipes with a T-6 flange mount on the end.
Then, you cut a round hole section on the roof of the pipes and installed a wastegate flange mount there), the exhaust flow would 99% of the time be traveling thru the pipes, the waste gate would be closed, and the exhaust flow would not pass thru the wastegate.

When you have a given boost pressure the wastegate would start to rob a portion of the exhaust from each pipe but the majority would still be driving both sides of the Twin Scroll turbine wheel.

At some point if the wastegate were large enough, it would divert enough exhaust flow for the turbo to maintain a given boost pressure.

You are not robbing exhaust flow from the turbo making "X amount of Boost", you are removing EXCESS exhaust flow to maintain a given "X amount of Boost" Pressure.

A 45mm wastegate should allow "control" if you are not running 40 psi of boost.

People run dual wastegates because the turbos are typically some distance apart.
Connecting a long pipe between the turbos to a single gate would be a poor design.
That is not the case with your single turbo installation.

I tried to find a picture on the web but had no luck on a quick look.

Tom V.

Thanks Tom, I think I understand it alot better now.... I tried to find the merge like 70bird uses, I have included a picture of it below, but I can't seem to find that merge anywhere! It would be easy to mount the gate in it, and I believe that what he did.

[TransAm 474]

And here is a picture of another guys I had saved, he is using a similar merge, and mount his gate there as well... but I have had no luck finding the merge they are using for some reason

[73 TRANSAM]

Be careful on mounting the WG on top of that merge. I did that on mine with a 2 lbs spring on a 60 mm Tial gate and I can only get the boost to 13 psi as its lowest setting. I had to redo mine to get a better placement with the help of CHARLIE. Lots of trial and error and I believe I finally have it fixed. I will let you know when I get my junk done.

[70 bird]

This is a side viev of the merge pipe...……


I have a 50mm china gate on it.

[TransAm 474]

Originally Posted by 70 bird

This is a side viev of the merge pipe...……


I have a 50mm china gate on it.

Thank You, which China gate do you use? Have you had good luck with it? I have seen some people use them successfully, and others say you can have problems, but I guess you can have problems with any product. I seen VS Racing has a 50mm gate, and as far as I read, that company has fantastic feedback, but not sure what reputation his wastegate has....

[70 bird]

Its been a while, I think it was about $50 off of e-bay I don't know the brand. I took the gate apart and coated the valve stem with hi temp anti-seize before I installed it. I have not had any problems other than availability of springs. I bought an assortment off of ebay and had to trial and error to find the psi settings I wanted.

[Chris Petersen]

This is the merge that I used, just use the one with the right size you need, cut to fit. I'll have to see if I have better pictures at home sometime.

[TransAm 474]

Originally Posted by Chris Petersen

This is the merge that I used, just use the one with the right size you need, cut to fit. I'll have to see if I have better pictures at home sometime.

Thanks Chris, I appreciate the pictures. I would love to see more close up pictures of your merge and wastegate if you dont mind. What size gate do you use, and how much boost? Thanks

[TransAm 474]

Originally Posted by 73 TRANSAM

Be careful on mounting the WG on top of that merge. I did that on mine with a 2 lbs spring on a 60 mm Tial gate and I can only get the boost to 13 psi as its lowest setting. I had to redo mine to get a better placement with the help of CHARLIE. Lots of trial and error and I believe I finally have it fixed. I will let you know when I get my junk done.

Thank You, where did you move it to? I would like to see some pictures of your merge and wastegate as well, if you don't mind, it would be really helpful. Thanks

[TransAm 474]

Just as a side note.... I talked to Lance at JGS, and he said he would run his 50mm gate on my setup to control boost on the street. He said it would work fine, and should control boost down to a steady 5-6 psi easy enough, but I'm sure that is probably if it is placed perfectly.

[Chris Petersen]

Originally Posted by TransAm 474

Thanks Chris, I appreciate the pictures. I would love to see more close up pictures of your merge and wastegate if you dont mind. What size gate do you use, and how much boost? Thanks

The gate is a 50-60mm china knockoff I think. With a light spring in it, its around 6-8# so far. Not sure if it will boost creep as I have not made a full pass under power yet, been trying to tune the EFI myself on the street. Ned to get it to a chassis dyno soon. Have MegaSquirt controlling fuel and timing.

[Chris Petersen]

This would be the best way to do it, if you can package it.

[TransAm 474]

Awesome, thank you Chris, that helps tremendously

[charlie66]

Originally Posted by Chris Petersen

This would be the best way to do it, if you can package it.

Thats exactly the way its done....

what company makes that one?

[Chris Petersen]

Originally Posted by charlie66

Thats exactly the way its done....

what company makes that one?

No idea, did a google image search for "wastegate placement" and that image showed up.

[TransAm 474]

I tried to find one for a T6, but I didnt have any success yet. Most of them for the T6 points the outlet either forward or backward out of the turbo from the direction Chris and others have their turbos mounted. I couldn't find on that dumped downwards.

[charlie66]

You have to fab your own . It would be doable the way chris has his. Just make a branch from each pipe merging into one into the wastegate.. The key to it though is gettting the wastegate pipe or (in your case pipes) right in the 90 degree bend. You have to imagin a straight line as it 90's and put the gate right there. So the first path before the turbo is the wastegate then the turbo . Do that and you will be fine...

[Tom Vaught]

Originally Posted by TransAm 474

I tried to find one for a T6, but I didnt have any success yet. Most of them for the T6 points the outlet either forward or backward out of the turbo from the direction Chris and others have their turbos mounted. I couldn't find on that dumped downwards.

I have attached two images of the T-6 Borg Warner Turbocharger most often used.
If you look at the pictures you will see the Band Clamps that attach the Compressor Cover and the Turbine Housing to the CHRA. COMPRESSOR HOUSING ROTATING ASSEMBLY.

The CHRA is typically PINNED in a given location by some small pins and a drilled hole in the Compressor Cover and the Turbine Housing. You can easily remove the PINS and put the CHRA in the following position:

1) THE LARGE OIL DRAIN HOLE MUST PONT TO THE GROUND. YOU CAN SLIGHTLY TILT THE CHRA FROM PERFECTLY STRAIGHT DOWN ON THE DRAIN BUT NOT MORE THAN 15 DEGREES FROM VERTICAL. THE SMALLER OIL FEED LINE FITTING GOES ON THE TOP OF THE CHRA.

2) THE TURBINE HOUSING CAN HAVE THE EXHAUST COME IN THE BOTTOM OR THE SIDE OR EVEN FROM THE TOP IN ORDER TO "PACKAGE THE TURBO IN THE BEST PACKAGE LOCATION. By removing the pins and losening the band clamp you can set that position for the turbine bousing.

3) The compressor cover can also be "clocked" (again remove the alignment pin) and put it where it needs to go. People figure out the compressor cover pretty easily, most do not know about the turbine housing position capabilities, and MANY SCREW UP THE OIL DRAIN WHICH SHOULD ALWAYS DRAIN DOWNWARD, NEVER HORISONTAL OR WITH A LOOP /BOW IN THE DRAIN LINE THAT WILL TRAP OIL. ALWAYS DOWNWARD.

Tom V.