I've just learned something today.

 

I have a toyota tacoma and that valve cover looks very familiar

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted92 &raquo;</TD></TR><TR><TD CLASS="quote">The purpose of it is to allow the turbo to freewheel on the line to spin up as fast as possible if you're having trouble building boost off the line with a massive turbo on a little motor. The second purpose is to be able to precisely control boost coming out of the hole. It's more precise and faster reacting to control any air being bled off of the cold side of the motor to control boost, rather than trying to control the amount of gas going into the turbine side and controlling the speed of the turbo shaft. Is this great for reliability? No, because you can overspin the **** out of your turbo(s), but it works nicely on race cars. This stuff is becoming very popular on traction limited cars as well as cars running a clutch or clutchless manual, basically anything without a torque converter benefits bigtime.</TD></TR></TABLE>
Good info, i learned something new as well today

 

Also, I bolded the part about cars running a clutch instead of a torque converter or any traction limited situation because I can see this taking off for FWD Honda motors. It takes a lot to get a GT42R spooled off the line, and the cold side wastegate can help you hold traction down the first half of the track much better.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HiProfile &raquo;</TD></TR><TR><TD CLASS="quote">I understand now, gives me yet another reason why race turbos take a **** after so few passes.

In other words, its maxing the turbo out by putting 100% exhaust energy into it, and making the comp wheel almost effortless to move. Slam it shut [and switch to exhaust gas diverting w/'real' WG), burn rubber.

If there was a rather inexpensive way to measure 100k+ rpm's of the compressor wheel, you could make a cold-side WG restrictor so it wouldn't overspin.</TD></TR></TABLE>

You're absolutely right, you have no way of limiting how fast the turbo will spin and that is becoming a source of failure. That's pretty much why the Garrett GT55's arn't lasting very long on race cars, they run a fairly small shaft, lots of boost, and running a cold side wastegate it's very easy to break them.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted92 &raquo;</TD></TR><TR><TD CLASS="quote">Also, I bolded the part about cars running a clutch instead of a torque converter or any traction limited situation because I can see this taking off for FWD Honda motors. It takes a lot to get a GT42R spooled off the line, and the cold side wastegate can help you hold traction down the first half of the track much better.

You're absolutely right, you have no way of limiting how fast the turbo will spin and that is becoming a source of failure. That's pretty much why the Garrett GT55's arn't lasting very long on race cars, they run a fairly small shaft, lots of boost, and running a cold side wastegate it's very easy to break them.</TD></TR></TABLE>

WOW...very good info. These are the kind of posts that i miss from the old days of the FI forum

 

cool, i guess ya learn something new every day. i think that car is the RWD celica from florida (?) that was running with the RWD Eclipse of Brent Rau in some outlaw class or whatever. i saw it at NOPI Nationals in Norwalk this year. awesome car, wish i would have gotten to see this in person!!

 

its luise from paridise racings car yes that is a rad they ran gas last year. they never had a chance to use the cold gate i was told when i asked them how well it worked