Brinkley

I have a Boxster Racecar that has a 996 3.6L in it. I have been running a set of FVD headers from the original 3.2L (obviously the headers for the 996 would not work in a boxster).

So, I have a bent/cracked header and I'm wondering if the newer 3.4L boxster aftermarket headers would...

one - bolt up to a 996 3.6L
two - would the headers fit up around and through the original 986 suspension etc.?

Anyone who might have some experience with with aftermarket headers on Frankenstein boxster's please help.

Thanks

insite

they will work, but pay attention to diameter. the 3.2L and 3.4L are well suited to 1-5/8" primaries, but the 3.4L is the upper limit here IMO. for the 3.6L, i think you'd want 1-3/4" primaries to make good power.

most of the aftermarket headers i see are either 1-5/8" or 2" primaries. i haven't seen any in between. if personally given a choice between the two on a 3.6L, i would choose the smaller pipe. the 2" are really way too big & you will lose low RPM torque pretty badly. you may want to ask tholyoak, as he's the king of frankeboxsters.

insite

EDIT: i just realized you were talking about the 987 retrofitted to a 986. in that case, i don't know!

harryrcb

Hi Brinkley, the bolt pattern are the same all the way up to 08 the ports all line up. I have some cheapo boxster headers in stock if you are in a bind you know my number. Harry

Brinkley

Insite,
No I think you misunderstand or I mis-wrote the OP. Keep in mind this is a hodge-podge of car/motor/headers.

First I have a 986 chassis and when I had a 3.2L in it I purchased a set of aftermarket headers for the 3.2L

When I put the 996 3.6L in the car I couldn't use that motors headers because they send the exhaust forward not aft. So we bolted on the 3.2L headers on the 3.6L motor. I don't know the diameter of the primaries but I like how you were talking about different sizes to look for and what the different sizes would mean to power and torque.

So please keep up the input and don't edit yourself because I think you have it right.

Thanks for the info!!!

P.S. Who is this tholyoak you speak of and how can I find him?

GTA_G20

Im in the same boat, I was thinking about using Cayman headers aswell.

sbelles

I'm in the market as well. I currently have some custom headers that were made by FVD for the 3.4 in a 986. The quality is crap. They have been patched quite a few times. Should have been made out of stainless.

I can attest to what Insite says. When I first put the engine in I hooked up the stock 2.5 exhaust it had monster power down low but the high end suffered. Once I put the larger ones one I gained top speed but lost some of the low end power. Please update with what you find.

Scott

insite

reworking my 3.4L exhaust now. i think this is also applicable to the 3.6L. going to the following:

1.625" primaries
2.250" collector outlet
2.250" cat bypass pipes (fabspees is making me a larger set; standard is 2")

i'm using the standard 2" muffler inlets to keep the velocity up. i think the gasses will have cooled alot by that point in the system. maintaining 2.25" to the end would probably cause some velocity loss, which would in turn cause the pressure to increase & will reduce the scavenging effect.


my old system uses 2" primaries + the stock cat pipes. the primaries are WAY too big; my problem is the reverse of sbelles: gutless down low and SCREAMS at high revs. i did the math; my headers are tuned to a torque peak of 14,000 RPM's for that motor. that's a bit higher than i tend to run it......


my fabspeed pipes won't be done for a month. once i have everything assembled; i'll post back here.

budmanv24

The 3.6L has a larger exhaust port than the 2.5L, 2.7L, 3.2L, and 996 3.4L mils. It is the same size as 987 3.4L engines. If you want to go to a 987 cayman s/boxster s exhaust you have to go full montey as none of the pieces are interchangeable. You can't use 987 headers with a 986 muffler, etc. I currently have a Capristo Cayman S exhaust installed on my 99 with a 996 3.4L. Fit was actually better for me than exhaust components designed for the 986 because my 986 exhaust slightly rubbed on the sway bar with the dropped motor mounts.

KnowSomeStuff

+1

Use the Fabspeed CaymanS headers on your 3.6. They are a direct bolt up. Fab from the 3 bolt flanges back with 2.25 tubing. I run this through 3.6L stock cats and no muffler. Its easily supports 350hp and 300+ lb ft of tq.

Using this in the 986, you will have to move the brake line holder on the passenger side and both wheel speed sensor brackets (cut them off and move them up 1inch) IF you plan to run the pipes where Porsche ran them in the 987 chassis.

The **** poor quality of the headers available flat out amazes me.. and people suck them up like they are going out of style. The $200 headers where designed to fit all 3 Boxster engines. Does that make sense to anyone? It means they work "ok" on a 2.5 but don't work very well on a stock 3.2.

We have repaired the Fabspeed headers 2-3 times now on a track car. They are pretty good, but the collector is junk.