anyone running Twins with a single WG?
Is anyone out there doing something like this? Ive searched the forum and searched multiple "show me your setups" threads and I haven't spotted any.
some obvious advantages would be cheaper (1 WG, 1 Solenoid), less stuff to break/fail, less plumbing.
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I'd hate to see you fab up your kit for a single wastegate only to find out that your trying to run "x"psi but it creeps to "xx"psi.
I'm just pushing the issue to get as many peoples thoughts as possible, I certainly hope nobody is getting bent on this topic, Im probably gonna run twin 38mm's or 44mm's anyway, but supposedly its been done before and its more of a curiousity thing at this point to find some feedback about it.
I'm just pushing the issue to get as many peoples thoughts as possible, I certainly hope nobody is getting bent on this topic, Im probably gonna run twin 38mm's or 44mm's anyway, but supposedly its been done before and its more of a curiousity thing at this point to find some feedback about it.
You can have a tiny motor with huge turbos and have no problem with running a single small wastegate because the motor produces barely enough energy to spin the turbines.
Or you can have a big motor with small turbos and have problems regulating because there is just way too much exhaust flow/energy for the amount of boost you are trying to maintain.
The latter was my problem.
I have a 440ci with twin T61s and twin 38mm gates and I was trying to maintain 7psi. Well it constantly crept to 9psi and even 12psi on occasion. The turbines were way too small and the motor flowed a ton of air. The wastegates could not bypass enough exhaust energy away from the turbos to maintain 7psi. Also, the wastegates had terrible bends and wasn't plumbed ideally. Thus I re-plumbed in some twin 50mm gates, installed larger turbos, fixed the backpressure issues and I have no problem maintaining 5psi.
I'd rather oversize than undersize in this case.
As far as a boost controller...it can only help so much. No boost controller can compensate for the physical size and max flow limit of a wastegate setup.
I met you down at Gary's last month; sounds like you're making some progress on the Bimmer project. As far as using 1 or 2 wastegates, either way can work...just do whatever is easiest from a plumbing perspective. I've seen guys use a single gate on twins when both turbos are very close together, but it wouldn't make much sense to run 6+ feet of plumbing across the car, into a common wastegate, if the turbos are far apart. The gate itself, as well as the way it is plumbed, will determine the minimum boost level. A controller can only raise boost, not lower it, from that minimum level.
Good Luck,
Rob
1.the extra piping will allow the exhaust to cool and slow down velocity wise causing though a little, more back pressure
2. all the extra piping would cost more than another wastegate if ya went that way
3. a wastegate is to control boost and it wouldnot control for **** on a setup like that. it would boost creep to hell because it would be near impossible to get the exhaust gasses from both turbos to have a clean shot at the wastegate
I met you down at Gary's last month; sounds like you're making some progress on the Bimmer project. As far as using 1 or 2 wastegates, either way can work...just do whatever is easiest from a plumbing perspective. I've seen guys use a single gate on twins when both turbos are very close together, but it wouldn't make much sense to run 6+ feet of plumbing across the car, into a common wastegate, if the turbos are far apart. The gate itself, as well as the way it is plumbed, will determine the minimum boost level. A controller can only raise boost, not lower it, from that minimum level.
Good Luck,
Rob
Havent made any real progress yet, still collecting parts and working to save up money. I should be starting it very soon.
I just keep getting into discussions with other turbo people and things keep snowballing into odd configurations, so I decided to get some outside point of views from people I dont actually know

1.the extra piping will allow the exhaust to cool and slow down velocity wise causing though a little, more back pressure
2. all the extra piping would cost more than another wastegate if ya went that way
3. a wastegate is to control boost and it wouldnot control for **** on a setup like that. it would boost creep to hell because it would be near impossible to get the exhaust gasses from both turbos to have a clean shot at the wastegate

Thanks for everyones input on the subject. Glad almost everyone was able to make worthwhile on topic posts.
Ill probably just stick with the dual 38mm's on the GT35R's with .82 A/R turbine housings





