Wastegate on Coldside pipe

[Voltwings]

Yes, you read the thread title correctly. Was looking at centrifugal superchargers the other day and saw they have whats called a "torque booster." For those unfamiliar with Centri-chargeres, basically its belt driven, and the boost goes up as RPMs increase, netting your peak boost at redline. Its a very flat torque curve and a very linear powerband. However, with a "Torque booster," you end up with a nice fat mid range for torque. What it essentially is, is a smaller pulley that would net you around 20+ psi (most systems run 7-9 for reference), but uses a wastegate on the coldside pipe to control boost to 7-9 psi. With this system, you basically get your boost the entire rev range, not just at redline. Seems pretty spiffy.

I can think of a few good reasons why this would be cool on a turbo setup, but can also think of several as to why its a bad idea, but just wanted to shoot the shit and see what everyone else thought. I havent come across any super interesting discussion threads lately, and to be quite honest, its friday and i dont feel like doin shit at work lol.

[2.0t03speed]

so basically you would block off your current wastegate and run your turbo flat out then use their cold side wastegate to vent the charge pipe to bring the boost down. i could see this being a bitch to tune for without a relocated maf. That and not being good for the life of the turbo.

[Voltwings]

Originally Posted by 2.0t03speed so basically you would block off your current wastegate and run your turbo flat out then use their cold side wastegate to vent the charge pipe to bring the boost down. i could see this being a bitch to tune for without a relocated maf. That and not being good for the life of the turbo.

you know haha, these setups are blow through, i didnt even think about the MAF.

Honestly i feel this only works with medium sized turbos.
Too small like the K04, we're already running it wide open so it means nothing
Too big like a 6262, 6466 ... and yeah you're putting like 40-45 psi into your system and then bleeding a lot of it off. Granted people making power on these turbos are running 30+ anyways, so maybe its not too bad in that case.

Imagine like a 2871 - 3071 though, 100 WGDC would ramp that shit up stupid quick and then just have what i feel would be a slick power band... granted i think thats the point of a manual boost controller anways ... maybe this thread is pointless haha.

[Outlaw4shrt]

doesn't the guardian angel already allow you to do this?

[2.0t03speed]

the guardian angel is a fail safe not a active all the time means of boost control.

[Outlaw4shrt]

Originally Posted by 2.0t03speed the guardian angel is a fail safe not a active all the time means of boost control.

what's the difference? it lets the bpv or bov open when a certain boost target is exceeded. it's just a boost controller for the bpv instead of the wastegate, correct? you could use it as an active all the time means of boost control if you wanted to.

[Voltwings]

Originally Posted by Outlaw4shrt what's the difference? it lets the bpv or bov open when a certain boost target is exceeded. it's just a boost controller for the bpv instead of the wastegate, correct? you could use it as an active all the time means of boost control if you wanted to.

that saves over boost, BPV's only have two functions, opened or closed. They're not actually designed for CONTROL.

[Tokay444]

a waste gate only has two functions. open and closed.

[El_Diablo]

Wastegates in some cases can be regulatory devices, slowly cracking open until enough flow is reached and then staying there or slowly closing as more compressor flow is needed.

Either way, his doesn't work for turbo's. I was actually one of the earlier guys to do this back in the day on my Mustang.

The idea is that you put an incredibly small pulley on your supercharger and the wastegate then bleeds off the excess boost back into the intake pre-supercharger which does work with MAF systems (mine was a draw through) but can cause some funky readings from time to time. In doing this you basically spin the supercharger faster so that your desired boost hits sooner and then you bleed the rest to maintain your desired boost until redline. This does create quite a bit of heat however.

The reason it doesn't work on a turbo is because you cant make a larger turbo spin faster and then bleed off boost. The wastegate already performs a boost control function in the exhaust. Basically the closest you could get would be to run something like a K04 with no wastegate, letting it spin as high as possible but bleeding off anything above that which would mean you're making all kinds of heat for no benifit and you would also be overspinning the turbo.

[Lex]

The exhaust wg slows down the turbo by diverting gases. The compressor wg will speed up the turbo instead and shorten its life as well as drastically reduce efficiency.

The GA operates on this principle but not meant to control boost - just lower it to a safe level if it runs away.

[El_Diablo]

http://youtu.be/LStlqe64m4M?t=1m


@Tokay444; This shows how a wastegate can start to crack open prior to full boost and therefor "float" in a regulation position, opening and closing further as needed.

[Matrix311]

So you want to run a setup like this? I saw this at a local car show last Saturday and this guy is pushing out 2,250whp. It's pretty insane!





Oh yeah and check out this video. Just listen to that thing spool up when they show the video of the rear of the car.

1966 Nova Glen Bolz firebird raceway 03.30.13 - YouTube

1966 Nova Glen Bolz firebird raceway 03.30.13 - YouTube

Sent from my SCH-I535 using Tapatalk

[Tokay444]

Originally Posted by El_Diablo Wastegate Spring Rate and Spring Pre-Load Explained - YouTube @Tokay444; This shows how a wastegate can start to crack open prior to full boost and therefor "float" in a regulation position, opening and closing further as needed.

Oh no doubt.
But it still only has two modes. Open, and closed. Anything that isn't closed, is open. Regardless of how much.

[superskaterxes]

Originally Posted by Tokay444 Oh no doubt. But it still only has two modes. Open, and closed. Anything that isn't closed, is open. Regardless of how much.

[Tokay444]

i have that same feeling.
like when people think compound turbo systems only work in theory.