Headers, Turbo's, & Sound
 

I am switching to Alphawerks headers with my TN kit. Is the sound going to change going from the stock manifolds to headers?

Respect
JET

i changed my headers as well. so we will find out together lol.. I havnt finished installin my new block yet.. the main thing im worried about with after market headers on the turbonetics kit is an increase in boost threshold (the rpm at which you hit full boost). Supposably thats what other have ran into when installing aftermarket headers

More or less lag?

I am using the crawford headers and a t66 turbo and hit full boost at 4000rpms

Expect more lag, more noise, more broken band clamps, more heat in the drivers side footwell, and slightly more peak whp. I only dynod about 10whp more with my aftermarket headers, but the spool time was 300-600rpms later and the overall area under the curve was less.

The key to help you out would be to get the headers jet-hot coated AND wrap them in header wrap. That'll help decrease the lag some.

I don't think that would make much of a noticable difference. It certainly doesn't with stock manifolds.

How much boost were you pushing with the headers? Your sig says 9psi.... I'll be pushing 14.5 so I don't think it will affect spool up. The headers are being sent out for Jet-Hot 2000. Was the noise favorable? Did it sound good?

Respect
JET

You're going to need to do some significant modification to the downpipe to get them to fit with the headers without touching the body or the header itself. We did slightly modify the downpipe on my car but it was still rubbing against the body at the v-band clamp. It eventually broke the clamp and caused a leak before we removed it. This was the cause of the "noise" I referred to previously.

As long as you modify it in a way as to not contact with any amount of engine or chassis movement then you should be fine. Seeing as the headers are pre-turbine/wastegate, I wouldn't expect them to change the exhaust note significantly. You might notice a slight difference in resonation, however. I don't specifically remember if there was a change in the way my exhaust sounded when I had them, as the exhaust leak and rubbing drowned it out.

You should still see a slightly delayed spool with the headers regardless of the level of boost you're running. Of course, it will naturally take slightly longer to spool up at higher boost levels or on a different turbo so the change might not be something you're even aware of.

I'd be interested in seeing a before/after between the stockers and aftermarket headers to see if they make much of a difference on a larger turbo and/or at higher boost levels. Of course, that's easier said than done...

if it keeps the heat in, it'll make a difference in spool.

In theory, but I believe it will be a minute one. I don't think I'd bother putting both on, just the coating itself. The main bonus in doing so would be the decreased engine bay temps over spool.

One concern some may have in coating/wrapping headers on a turbo application is that they were not designed to handle such intense heat. The thin-walled aftermarket headers could have some issues with longevity. Of course, no one has had any failures due to this to my knowledge.

The main issue with the aftermarket headers on the market now is they were designed with N/A purposes in mind. In most cases the runner diameter is increased drastically which will increase exhaust volume but may also decrease exhaust gas velocity. The drop in velocity will hurt spool up times without a doubt. Now if someone developed a set of headers that would maintain a decent exhaust gas velocity while still increasing volume we might have something worthy to switch too.