Twinscroll turbo sizing
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Joined: Jul 2009
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From: enjoy racing
The s200 series from bw might also be something to look into. You can find them new for less then a $1000 and they have a decent array of turbine housings.
Something like this
http://www.full-race.com/store/turbo...670-turbo.html
Something like this
http://www.full-race.com/store/turbo...670-turbo.html
Joined: Mar 2009
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From: avondale AZ
Bigger is *almost* always better on a T4 divided housing, the reason is, If you have an open T4 .88a/r housing the internal volume is larger than that of a .88a/r divided housing, so in order to keep back pressure in check you want to go larger than you would normally on an open housing. If you are using Borg Warner stuff i would suggest .91a/r to 1.10 in the S300SX lineup, with borg warner stuff you can also mix and match turbine wheels to achieve maximum spool or maximum top end...
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From: Seattle / Kalifornia
Bigger is *almost* always better on a T4 divided housing, the reason is, If you have an open T4 .88a/r housing the internal volume is larger than that of a .88a/r divided housing, so in order to keep back pressure in check you want to go larger than you would normally on an open housing. If you are using Borg Warner stuff i would suggest .91a/r to 1.10 in the S300SX lineup, with borg warner stuff you can also mix and match turbine wheels to achieve maximum spool or maximum top end...
It's not about in order to keep back pressure, rather in order to provide enough flow capacity. I agree with what you're saying though, it's why I rarely find effective setups on small or mid frame turbos. Certainly need to up-size as a result of the divider.
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From: New Jersey
Irishflame27 is correct. You want to go as big as possible, being the hot side is not at large as if it where a single scroll. I forget the number but you need to X it by .xx to get the more accurate number of how it will perform.
I have a divided GT35r with a 1.06 hotside and at 24.5 lbs I made 635HP, The efficieny goes to hell up high (this is with an open downpipe as well)
I have a divided GT35r with a 1.06 hotside and at 24.5 lbs I made 635HP, The efficieny goes to hell up high (this is with an open downpipe as well)
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Joined: May 2010
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The s200 series from bw might also be something to look into. You can find them new for less then a $1000 and they have a decent array of turbine housings.
Something like this
http://www.full-race.com/store/turbo...670-turbo.html
Something like this
http://www.full-race.com/store/turbo...670-turbo.html
Seems like the 5858 and the 5862 are out of the question. Their exhaust housings don't seem large enough. The 5862 has a .84 but I think that would still choke the engine out.
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From: enjoy racing
Don't tell Raffi you bought AFI manifold, he'll probably charge you double. If you really want a fast spilling turbo I would go for the s200 series. It's in the same class as the gt30. The s300 series is overkill for your goals and you will give up spool time with it
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Why would he charge me double? He actually suggested AFI's if I didn't buy theirs.
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I'm piecing together an AFI turbo kit. I have the manifold and now I'm searching turbos. I'm interested in the 5858 but it's largest AR for a T4 is .68. Next is the 5862 it's largest AR is .84. Last turbo I was looking at is the Borg Warner 7670. It has plenty of AR choices ranging from .83 to 1.22. This one seems like thebest choice for the power I'm looking for. I've read a couple threads saying that you need large AR's with a twinsscroll mani. I'm not looking for crazy hp, 400-550. I just want a fast spooling street setup. If these turbos are to small, I'll setup to a 6262 but I feel it may leave a little to be desired on the street. I'm basically looking for GTX3076 or 71 performance without the price.
Anything smaller than say a GT35R flow capacity nets poor results on a twin scroll. Thus the applicable useage of a twin scroll is for 600hp+ applications.You're talking 400-550hp, that's too small to bother with twin scroll from what I've seen. In theory the twin scroll sounds great, yet every setup I see it there's too few gains.I think the GTX3076 and a equal long runner of quality is what you should run, skip the twin scroll setup. Your lag will be so minute it's not worth even discussing. I hit INSTANT spool with a equally matched turbo.-Greg
Irishflame27 is correct. You want to go as big as possible, being the hot side is not at large as if it where a single scroll. I forget the number but you need to X it by .xx to get the more accurate number of how it will perform.I have a divided GT35r with a 1.06 hotside and at 24.5 lbs I made 635HP, The efficieny goes to hell up high (this is with an open downpipe as well)