Carl Fausett

?? have you checked to make sure you are not running lean? I'd like to know why your header collectors would be getting that hot. That's not normal.

hacker-pschorr

Local guy has installed more than a few sets of MSDS headers on 928's and always welds on another flange to strengthen the area.

Ducman82

my msds flanges never leaked, but that being said i hate bolts and gaskets and added V-bands anyway

mark kibort

lean wouldn't be the problem, (lean, actually reduces EGTs) stoich would. and if he was running at stoich, i would think that it would be pinging like a bangie.
if you repeatedly rev the car a lot , you can get a lot of unburned fuel in the bottom header and it can cook things as it ignites there.

terry gt

Carl , lean was a possibility , was getting 350 at the R wheels . and running out of fuel . now I have 36# injectors . Still need to tune it . The MSDS headers / cats/ 2 1/2 duels added 31 HP

mark kibort

how were you running out of fuel.... I have 30lb/ers and im drowning in fuel at 375rwhp. (and even lowered the fuel pressure to 44lbs)
post a dyno run.... what fuel pressure are you running. stock ECUs? what other mods? Just some radical cams? that's some good power!
with a stock 5 liter and GT cams I got 335rwhp but had to up the fuel pressure with stock maps to 72psi. worked well though!

terry gt

Injectors at 100% and the air fuel ratio was unstable . for mods see my description below.
I have a set of level 2 devek headers , always wondered if that would make any difference .
uneven intake runners /batch firing injectors/ odd firing order / uneven length headers ? maybe the uneven headers work better .

terry gt

Carl , 1 more o2 sensor bung on the other header , so the car can be tuned with a wide band sensor .

ptuomov

I like the straight pipes. I am not sure how beneficial exactly equal length is relative to getting straighter flow paths. But that may just be my turbo thinking.

Thicker flanges and a second O2 port might make sense for the next batch, as suggested earlier.

Do you have shots of what the merge collector looks inside, from the collected side?

Carl Fausett

There is a trade-off here. Rule-of-thumb is two 90's = a 1 psi pressure drop or increase depending on which side your on.... so yes, going nuts with the bends just to get perfectly equal length primary's can be detrimental...

Carl Fausett

V-band clamps on mine... test-fit, tacked in place, finish welds came next.

Clearing the lower bell housing so we could service the clutch with the exhaust up. Note these are dual 3.5" pipes, so if they look biggish, they are.

Ducman82

better flow. and you would have to basically remake the headers for the new collectors. unless you have the skills and free time to do that, it would be cheaper to get the new ones.