Straight pipe post turbo

[MattNC]

I've had the BMI turbo installed for about a year and a half and love it, but I am ready to get rid of the exhaust going under the frame rail. Rerouting it to be in the tunnel will involve moving a lot, including transmission cooling line and I am concerned it will still place a hot pipe close to things that may not like that.

I'm thinking about just dropping it straight from the turbo and dumping to the ground directly. Does anyone with turbo experience see a problem with this? So post the turbo it would have maybe 20" of straight pipe and aim straight for the ground. I am wondering if I should sweep it back a bit, or maybe explore if there is a short exhaust/resonator I could put on. I think the turbo will kill most of the sound, but if a short exhaust would work it might be good, also from a spark arrestor perspective. Thoughts????

 

[NDT]

You can try it but I am pretty sure it will be loud AF.

 

[chucky]

What was the old story about not running uncapped headers in real cold conditions that the cold air was bad on the valves ??? I never understood it but might be worth checking out !

 

[sue]

I've had the BMI turbo installed for about a year and a half and love it, but I am ready to get rid of the exhaust going under the frame rail. Rerouting it to be in the tunnel will involve moving a lot, including transmission cooling line and I am concerned it will still place a hot pipe close to things that may not like that.

I'm thinking about just dropping it straight from the turbo and dumping to the ground directly. Does anyone with turbo experience see a problem with this? So post the turbo it would have maybe 20" of straight pipe and aim straight for the ground. I am wondering if I should sweep it back a bit, or maybe explore if there is a short exhaust/resonator I could put on. I think the turbo will kill most of the sound, but if a short exhaust would work it might be good, also from a spark arrestor perspective. Thoughts????

One thing to consider is where that heat goes after exiting? Like is your rear axle going to be in that heat stream?
and I would not be concerned about noise because the vanes on the turbo normally???
do a good job of mitigating and absorbing the exhaust pulse noise.

 

[87cr250r]

Less back pressure is always better. On a naturally aspirated motor the high energy exhaust pulses in small tubes travel at high velocity which reduces their pressure (Bernoulli). A turbo engine benefits from no such effect post turbo. Bigger shorter straighter is better. With that said, I don't think you want the exhaust exiting under the vehicle because it is hot as stated earlier but it's also going to cover everything in soot.

If clearance is an issue, there is no rule that an exhaust pipe must be round.

 

[lpcoating]

Header wrap would help with your heat concerns.

 

[87cr250r]

Header wraps cause crevice corrosion on stainless steel piping. If you're dry all of the time this shouldn't be an issue. Heat shields are more effective, though. If you follow that route. Copy what modern cars do. They routinely pack hot exhaust systems in cramped places.

 

[MattNC]

I am wondering if maybe I can do the downpipe from the turbo, make a 90 bend swept toward the rear and maybe fit in a resonator or short straight pipe in the bit of space there in the tunnel and after the resonator/muffler do a downturn toward the ground mid-truck and dump toward the ground before it runs into space concerns in the tunnel. I need to get under the truck this weekend and play around with some ideas and cardboard mock ups. If I did the run I mentioned and at least a resonator it may knock down the noise and maybe drop the temp of the exhaust a little further before exiting. Right now my EGTs pre-turbo are typically 500-600 with some as high as 850-900 under load on hills, and the turbo should scrub a few hundred degrees off of that.

 

[AmarokK9]

Given the number of drain holes under the body...I'd be more concerned about exhaust gases entering the driver's compartment.

 

[Mogman]

Mine has no muffler can hardly tell the difference, defiantly not loud.
You do not want to terminate the exhaust under the truck.