Do I need wastegates ?????

05hummincummins

05hummincummins

smoked ya
Joined
Sep 5, 2009
Messages
79
i am thinking bout running twins on my pulling truck and have some questions. I will be running an S465 over an S485. The 465 is a 63x91 compressor wheel with a 83x74 exhaust wheel and a 1.10 T6 housing. The 485 is a 88x112 compressor wheel with race cover with a 96x88 exhaust wheel and a 1.32 T6 housing. My question is do i need a watsegate and if so how big? Where would i put it in the manifold or in the Hot pipe? Would i be able to use The lil brass pop off valves in the charge pipe or no? Never really messed with twins before this is a first so bear with me if i have forgot any info?
 
You will most likely need a wastegate in the manifold that dumps into the hotpipe which is typical of most compound setups. You should be fine without wastegating the primary. What are your plans for the truck. Drag racing? Pulling? Nitrous?
 
it will be a dedicated puller. was gna try n run the 2.6 class but with all the bs i think im goin to step up a class.
 
The most tunable set up would be 2 waste gates. One off the exhaust manifold, tied into the hot pipe between the 2 chargers. The other coming from the hot pipe between the chargers and venting to atmosphere. A set up like that will allow infinite tuning and very accurate control of your drive pressures. Those brass blow off valves are a joke. I still can not figure out why they were ever used in a twin set up. The are for water for 1, and they do not flow enough air to protect in a overboost situation anyway. Just a place for a boost leak to cost you power.
 
05hummincummins said:
it will be a dedicated puller. was gna try n run the 2.6 class but with all the bs i think im goin to step up a class.
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Your 2.6 and 2.8 class will allow you to run twins?:what: I would check with the local pulling association before you worry about needing to put a waistgate in your twin setup or not...
 
No im gna bump up a class. around here we have 2.6 and the next class up is pro street. the pro street is unlimited single and 3.0 twins.






cbtoyz said:
Your 2.6 and 2.8 class will allow you to run twins?:what: I would check with the local pulling association before you worry about needing to put a waistgate in your twin setup or not...
Click to expand...
 
you need to at least run a waste gate on the secondary turbo or you are going to have a restriction of exhaust flow at the housing of the secondary turbo. this will really hurt your horsepower. you will also end up with a restriction at the housing on the primary turbo but it will not be as bad as the secondary turbo. lack of waste gates will cost you horse power and cause more heat in the engine.
 
Why would u want a t6 on ur secondary? What rpm range are u looking at?my brother runs a 72/83/.90 over a 83/96/1.32 with no gates but he is only turning 4k
 
You don't need one if you size everything right (i.e. use a large secondary turbine wheel/housing). But you might want at least one so you can use a smaller secondary turbine wheel and housing for better spool and torque and not over speed it.
 
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Well i appreciate all the help but i just got the chargers in today and did some measuring and its not an 88x112 compressor wheel its a 80x112 compressor wheel. im not sure how thats gna effect the performance. any ideas?
 
Rethink your setup, forget about brass pop up valves, 3.0twins class? Really?
 
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