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Dual Wastegates

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Old 10-19-01, 02:36 PM
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Question Dual Wastegates

I am interested in anyone running a dual wastegate setup. Why did you do it, do you have graphs from before and after? How much did spool-up improve?

Yes, I know why you would do it, just looking for info from peeps that have done it.

Anyone?
Old 10-07-09, 06:29 PM
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After 8 years and still no one on this board has done this?
Old 10-07-09, 06:31 PM
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WOW.. That is one old post dude....

I run dual gates... Spool up doesn't change...

I chose to run dual gates to have better control of boost...
Old 10-07-09, 06:38 PM
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a couple have just look at some peoples build threads.... after 8 yrs you havent done this? lol must not have been important. but seriously just cause your running dual wastegates dosent improve spool up.... UNLESS it was part of swapping a divided manifold and turbine setup's single wastegate to duals, so it would completely divide the exhaust pulses to the turbine. with the single wastegate setup it would have bled the pulse into the other runner via the wastegate piping killing the effectivness of the pulse to spool the turbo. hope that answers some of your question cant say how much it would improve spool though i havent done it

z
Old 10-07-09, 06:57 PM
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No, I became side tracked with my car. It is all cozy in my garage. I am back to working on it though. Trying to decide if I want to sell my one big wastegate and put on two smaller ones.

Yes, this thread is old. I did a search for all the threads I started and this one didn't have any information in it
Old 10-07-09, 07:16 PM
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how much boost are you planning to run?
Old 10-07-09, 07:29 PM
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17psig on pump and 22psig on 103.
Old 10-08-09, 10:47 AM
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I went from a divided 60-1 with single wastegate to a divided GT35R with dual wastegates and my spool improved dramatically. With both setups the runners were very short. The original setup didn't reach full boost (14 PSIg) until nearly 5K on dyno pulls, and the new setup is all in by just over 3K (12 PSIg).

Can't say how much of the difference is due to the turbo and how much to the manifold. Pretty sure the boost level didn't make much of a difference.
Old 10-14-09, 06:12 PM
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what size wg are you using elwood? and what diameter are you runners?
im looking to use 2 of th enew tial 38s with 42mm runners with TO4z, was suggested to use 2x 44 but I think its well overkill and far more expensive
Old 10-14-09, 06:55 PM
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i was running a single 60' before now im in the middle of swapping to dual 44's. the main reason why im doing it is to control boost better.
Old 10-14-09, 07:57 PM
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Originally Posted by elwood
I went from a divided 60-1 with single wastegate to a divided GT35R with dual wastegates and my spool improved dramatically. With both setups the runners were very short. The original setup didn't reach full boost (14 PSIg) until nearly 5K on dyno pulls, and the new setup is all in by just over 3K (12 PSIg).

Can't say how much of the difference is due to the turbo and how much to the manifold. Pretty sure the boost level didn't make much of a difference.
There is a huge difference in spool between those two turbos. 5k is super late for a 60-1 also, should have been near 3800rpms, unless you were running a 1.32 or something...
Old 10-14-09, 08:18 PM
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Originally Posted by enzo250
WOW.. That is one old post dude....

I run dual gates... Spool up doesn't change...

I chose to run dual gates to have better control of boost...


i run on bigs single. its a little cheaper running 2 small wastegates if you dont have the money.



BTW this thread has to be in the hall of fame as the oldest thread in history

kinda sad 8 years & no response
Old 10-14-09, 11:20 PM
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talk about a post brought back form the land before time.
Old 10-15-09, 06:06 AM
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2x 38 mm wastegates and a long equal length manifold and I'm never looking back.

As what Enzo said, the dual wastegates help considerably when managing boost. But a proper manifold is the way to go. I'll never cheap out on a mani ever again in life. BIG difference.
Old 10-15-09, 05:32 PM
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WG Sizes

Originally Posted by Bitchn7
what size wg are you using elwood? and what diameter are you runners?
im looking to use 2 of th enew tial 38s with 42mm runners with TO4z, was suggested to use 2x 44 but I think its well overkill and far more expensive
The single WG was a TiAL 46mm; the duals are TiAL 44mm. When I went dual, I used the 44mm WGs because they are much smaller and use V-bands. These attributes combine to make them package better.
Old 10-15-09, 05:34 PM
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Spool wouldn't change. The wastegate is still closed during spool up. Since dual gates would typically flow better you might gain a very small amount near target boost by holding them closed longer, but it would hardly be noticeable.
Old 10-15-09, 05:41 PM
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Originally Posted by 1Revvin7
There is a huge difference in spool between those two turbos. 5k is super late for a 60-1 also, should have been near 3800rpms, unless you were running a 1.32 or something...
I don't doubt the turbo made a big difference -- that's why I bought it. Both the 60-1 and GT35R had T4 flanges, with 1.00 A/R turbine housings.

Regardless of the cause, I'm happy as a clam.
Old 10-15-09, 06:31 PM
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Wouldn't a fully divided manifold with dual wastegates completely separate the exhaust pulses and help with spoolup and possibly peak power since the flow of the exhaust path is smoother?

thewird
Old 10-15-09, 08:44 PM
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Originally Posted by thewird
Wouldn't a fully divided manifold with dual wastegates completely separate the exhaust pulses and help with spoolup and possibly peak power since the flow of the exhaust path is smoother?

thewird
In theory it might. I am almost done building a turbo manifold that has a divider between both waste-gate runners all the way up valve on a single wastegate. I am going to see how it compares to a standard collected waste-gate runner setup.

On some of the bigger turbo setups( 42R+) and Half bridge motors running under 18psi the dual waste-gate setup is the way to go for boost control...
Old 10-16-09, 03:47 AM
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Originally Posted by 1Revvin7
In theory it might. I am almost done building a turbo manifold that has a divider between both waste-gate runners all the way up valve on a single wastegate. I am going to see how it compares to a standard collected waste-gate runner setup.

On some of the bigger turbo setups( 42R+) and Half bridge motors running under 18psi the dual waste-gate setup is the way to go for boost control...
Please let us know. I was planning to make a new manifold this winter as my existing one is tired and was thinking about running dual wastegates to help response as I have no issues controlling boost at all with my collected single wastegate setup. However, if there is no benefit then I'll just remake my old one?

thewird
Old 10-16-09, 07:16 AM
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Maybe I wasn't clear enough -- my engine is a streetported 13B-RE with -REW rotor housings.

The original setup:
- divided short runner T4 flange exh manifold
- collected wastegate runners that led to a single 46mm TiAL wastegate
- 60-1 turbo with 1.00 A/R turbine housing
- No boost creep, but near 5K RPM to achieve full boost

Current setup:
- divided short runner T4 flange exh manifold
- completely divorced wastegate runners; each leads to a 44mm TiAL wastegate
- GT35R turbo with 1.00 A/R turbine housing
- No boost creep issues, full boost by just over 3K RPM

My current setup keeps the pulses totally separate, which is why I went to the twin wastegates. I believe the totally divided nature improved spool, which is a generally accepted design guideline. The only way to quantify exactly how much would be to swap the 60-1 back in, since I changed two variables at the same time. But I suspect the fully divorced manifold was a part of the gain, since I don't think others have seen this much of an improvement simply by changing turbos.
Old 10-16-09, 07:18 AM
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Originally Posted by elwood
Maybe I wasn't clear enough -- my engine is a streetported 13B-RE with -REW rotor housings.

The original setup:
- divided short runner T4 flange exh manifold
- collected wastegate runners that led to a single 46mm TiAL wastegate
- 60-1 turbo with 1.00 A/R turbine housing
- No boost creep, but near 5K RPM to achieve full boost

Current setup:
- divided short runner T4 flange exh manifold
- completely divorced wastegate runners; each leads to a 44mm TiAL wastegate
- GT35R turbo with 1.00 A/R turbine housing
- No boost creep issues, full boost by just over 3K RPM

My current setup keeps the pulses totally separate, which is why I went to the twin wastegates. I believe the totally divided nature improved spool, which is a generally accepted design guideline. The only way to quantify exactly how much would be to swap the 60-1 back in, since I changed two variables at the same time. But I suspect the fully divorced manifold was a part of the gain, since I don't think others have seen this much of an improvement simply by changing turbos.
Do you have a picture of your manifold? I'd like some ideas.

thewird
Old 10-16-09, 11:31 AM
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5000 rpm is too slow for a 60-1 i used to have one and had full boost by 3700 (15psi) my t70 sees full boost just before 5k. Something was wrong with your setup and it's not from a single gate unless it was stuck partially open.
Old 10-17-09, 08:01 AM
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Manifold Pics

Unfortunately, these are the only pics I have. The ones that are out of the car show the setup as it was with the single wastegate. The installed pics are of the dual wastegate arrangement. I made it out of mild steel schedule 40 tubing, which is very thick, so hopefully it will last. The rest of the exhaust is 304SS.
Attached Thumbnails Dual Wastegates-underbody-wastegates-front.jpg   Dual Wastegates-underbody-wastegates-side.jpg   Dual Wastegates-turbo-4.jpg   Dual Wastegates-turbo-5.jpg  
Old 11-13-09, 10:34 PM
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wow, thats sweet elwood, i like that you had a completely divided manifold, makes the twin wastegates really make sense. and i cant believe this thread is 8 years old, and no one ever replied. :O


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