SS Autochrome Headers and X Pipe [Archive] - SmokinVette.com Forums

: SS Autochrome Headers and X Pipe


tstar
04-29-2007, 12:51 AM
I have been working with SS Autochrome on their newly designed Header system. Hopefully the final fabrication will be completed soon, in the interim they have a significant stock of this design and they’ve allowed the price of $400.00 shipped. PM me for info.

The Headers and X Pipe are made out of SUS 321 Stainless Steel. SUS 321 has Titanium added and has much better heat properties then the typical T-304. The flange is 3/8” thick with a 3”collector. The welds are very well done.
http://i142.photobucket.com/albums/r117/tstar99/SS%20Autochrome%20Headers/HeadersandXPipe.jpg
http://i142.photobucket.com/albums/r117/tstar99/SS%20Autochrome%20Headers/FlangeWelds.jpg

The design of the Headers is a Mid Length design. The overall length of the primary header pipe is governed almost exclusively by the target engine's rpm range, which is dependent upon wave tuning. Typically, a lower engine rpm range likes a longer primary pipe, while a high rpm engine prefers a shorter primary. The length of the primary pipes also affects torque. Where diameter affects the torque peak relative to rpm, the length affects the shape of the torque curve. Longer primaries provide more torque below the peak and reduce it past the peak. Shorter primaries provide more torque above the peak at the expense of below-peak torque. More torque in the low- to mid-rpm range is important to drivers who want that feeling of seat-of-your-pants performance on the street. Longer primaries also reduce the chance of escaping exhaust's being drawn back up another pipe.

In order to keep the torque curve the same for all eight cylinders, it is important that primary pipes be equal in length. Exactly how equal they have to be is more critical on uncorked race cars than for the vast majority of mild-engined street cars running through mufflers. In most applications, pipe length deviation of 2 to 3 inches on a set of full-length headers is not a problem.

Included in the kit are the Headers, X Pipe and X Pipe to Catback gaskets and bolts and A.I.R. Tubes. There is also a collector reducer included which is useless and I threw it away. The Headers are a “race” style with no A.I.R. tube provisions, however the A.I.R. tubes are provided and I opted to install them.

http://i142.photobucket.com/albums/r117/tstar99/SS%20Autochrome%20Headers/Almost.jpg

I pretty much followed an installation guide from LS1Tech on FLP Headers, The installation actually went very well and I encountered only a few minor design problems;

The passenger collector was pointing towards the outside of the car, about a ½” too far. I got it pried over without too much trouble but the mounting tab still doesn’t line up, I’ll fab a new tab soon.

http://i142.photobucket.com/albums/r117/tstar99/SS%20Autochrome%20Headers/Install/Completesystem.jpg

tstar
04-29-2007, 12:55 AM
One passenger primary was touching the AC line, I managed to get a ¼” air gap by bending the hard lines. It seems OK, but I want to get some more clearance in the future.

http://i142.photobucket.com/albums/r117/tstar99/SS%20Autochrome%20Headers/Install/HeaderACLineProblem.jpg

The Passenger front OS bung was a tad too high making the sensor very close to the bellhousing. Wasn’t really an issue but very close to being one.

http://i142.photobucket.com/albums/r117/tstar99/SS%20Autochrome%20Headers/Install/O2bungs.jpg

The X Pipe had a bit of pipe extending past the Catback flange, which I ground down with a hand grinder.

http://i142.photobucket.com/albums/r117/tstar99/SS%20Autochrome%20Headers/PICT0054.jpg

I just finalized my install of this exhaust package with a Dyno Tune. I’m very happy with the results!

http://i142.photobucket.com/albums/r117/tstar99/SS%20Autochrome%20Headers/Install/BeforeandAfterDynoSheet.jpg

Here is the list of parts and suppliers for my particular installation;

Ebay Headers and X-Pipe with gaskets
Exhaust mainfold gaskets GM P/N 12600530
A.I.R. Tube agskets
2 x 3" Thunderbolt Cats, Performance-Curve.com P/N 415300
2 x 3" stepped band clamps, Summit P/N WLK-33272
2 x 2.5" stepped band clamps, Summit P/N WLK-33226
2 x 3"-2.5" cone reducers, Summit P/N FLO-R3025
2 x 12” (approximate) 3” Pipe, cut too length
Optional – Ball and Socket Flange Summit P/N FLO-15925

MOTORCITYDMAN
04-29-2007, 04:04 PM
Thanks For Your Information On These Headers, I,ve Been Looking For Some On Ebay With No Luck,please Email Me Details & Pricing For My 2000 C5.i Want Them A.s.a.p. @ Motorcitydman @yahoo .com Or Cell Ph # 313-220-2277

tstar
04-29-2007, 11:40 PM
EMail sent!

I can't believe more owners aren't jumping on these! I guess it's a case of "If it sounds too good to be true... ect... "

99_vette
08-16-2009, 02:20 PM
I was just surfing around and found your post. For some reason I'm not able to PM you. I know this post is old, but I'm wondering if it's still available? $400 for headers and X pipe, sounds good to me.

Mr. Hyde
08-16-2009, 03:16 PM
I honestly expected more than 10hp and 7lb. out of LT headers. Maybe if the cats were eliminated there would be a bigger increase.