I have a set of bd twins that im going to be installing and was wondering if an aftermarket exhaust manifold would be worth it? I know there is HTT, BD, and ATS but I not sure if they will all work with the bd twins. Also will these exhaust manifolds make any difference over stock, besides dropping egt temps. Do they improve any hp or mileage?

Im just trying to figure out if it needed or not.

The twins arent installed yet along with the injectors and head studs. Waiting to get all the parts I need first.

 

I have an ATS manifold on my truck, besides the lower egts, the stock turbo on my truck spools up noticeably quicker than stock. If you are going with BD twins, I would recommend getting the manifold at the same time. It will help the engine breath better.

 

An aftermarket manifold is a must with twins, as you have the added weight hanging off of it. I doubt the stocker would last very long with your new kit. Any one of them will work as they are all essentially the same. I have both ATS and HTT myself and have a personal preference for the HTT, but that's just me.
mishkaya

 

BDs Twins is supposed to come with the manifold already i thought.. if it doesnt then YES definetly get one. the spool time is cut i wanna say almost in half.. at least thats what happend when i added it to my single. All your really doing is allowing for more flow. The more flow of exhaust gases hiting the wheel on the back of the turbo the quicker it will spool. the quicker it spools will not necessarily add hp but mileage it should help as the turbo spools lower down in the rev range which means more power earlier.

 

i also heard that the aftermarket manifolds are stronger so they can hold the extra 40lbs of turbo it now has to support.

 

Doesn't the BD twins have a support for the lower turbo? A good kit usually has one, so the manifold is only supporting the weight of the single turbo.

 

BD stopped including the manifolds with the twin kit because they were finding that people already had an aftermarket exhaust manifold.

 

well obviously in that case buy one

 

Got an HTT with Jet Hot Header coat on the outside. Has aslo been ported and polished insde.

 

did this help out on spool up?

 

Yes, also reduced back pressure and EGT slightly as well. Looks good too!


Only pic I have to show the manifold right now.