rmt advice
Thread Starter
Intermediate
Joined: Jan 2010
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rmt advice
guys, adding a rmt for a bit of spice and been looking at the exhaust route to see where i can separate the boost pipe to keep it cool. looking at it the best way looks to run one large combined exhaust along the route of one side and use the other side for the boost. i have an x pipe at the minute. should i lose the x pipe and just combine after the manifolds, keep the x pipe and combine further back, not do this at all as it will cause other problems? any thoughts welcome.
Burning Brakes
Joined: Jan 2007
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You want to limit the heat loss off the exhaust and minimize the bends and turns before you get to your turbo. Also limiting the internal volume of the exhaust will reduce turbo lag, so keeping it simple is probably best overall.
Thread Starter
Intermediate
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yeah thought the same thinking 4in insulated pipe to the turbo along the rhs underneath. Have some high temp pipe insulation that i've been told will work upto 700 degrees which should be enough and help keep the heat in. Will 4in be enough not to cause a restriction or does 5in sound better.
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Burning Brakes
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You want to keep pressure higher so the pipe to the turbo should not be more than 3 1/2 in. Louis Ott did a lot of tuning on his stroker engine with a single 3 , 3 1/2 pipes as I recall vs duals coming off headers. The 5 inch pipe would be way too large and hold too much exhaust (turbo lag) . The smaller pipes keep the exhaust speed higher so limit heat loss by spending less time in the pipe. I would consider using a three inch for ease of fabrication and cost of the pipe plus low end torque advantages. I think Mark Anderson runs a single 3 inch pipe on his very high HP stroker racecar.
Thread Starter
Intermediate
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brutus: thanks noted will investigate 3in for a start
lizard nice installs; what size turbo do you use? i was trying to route away from as much as possible to avoid heating it but looks like you've got problems with heat given out to gearbox/tube etc?
lizard nice installs; what size turbo do you use? i was trying to route away from as much as possible to avoid heating it but looks like you've got problems with heat given out to gearbox/tube etc?
Nordschleife Master
Joined: Apr 2003
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From: Abbotsford B.C.
I have not noticed any additional heat really.
And if it's a street car you will never notice more heat due to how little time you can spend on boost.
If its a track car, then you might want to have the pieces ceramic coated but past that you won't have an issue.
As to sizing the full rear would be about a T62 and the mid is around a T71/72.
And if it's a street car you will never notice more heat due to how little time you can spend on boost.
If its a track car, then you might want to have the pieces ceramic coated but past that you won't have an issue.
As to sizing the full rear would be about a T62 and the mid is around a T71/72.
Addict
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From: Austin, Texas
For a 32v, use a 3" to the turbo. For a 4.7 or 4.5, use a 2.5". I've seen 450rwhp cars with 2.5" exhausts & 800rwhp cars with 3" exhaust: not going to hurt too much to keep it conservatively sized. 3.5" will only cause more drone, slower spool since slower gas velocity. With the turbo mounted so far back, it's velocity driven, not necessarily heat as turbos are typically both velocity & heat. Due to the size of our engines & the low boost, the velocity is there to compensate for the lack of heat.
I've used 61mm, 62mm, billet 62mm, & 67mm before: all work great, some spool faster than others, esp. BB turbochargers which will run you about $4-600 more per-turbo to use because of recent price increases + fittings.
Mark
-86.5 turbo, '82 5.0 turbo, '88 944 Turbo S, '91 911 turbo 3.6.
I've used 61mm, 62mm, billet 62mm, & 67mm before: all work great, some spool faster than others, esp. BB turbochargers which will run you about $4-600 more per-turbo to use because of recent price increases + fittings.
Mark
-86.5 turbo, '82 5.0 turbo, '88 944 Turbo S, '91 911 turbo 3.6.