Is this statement correct?

[timspu]

I have a stock CIS 930 and the AFR's on boost are high 10's and mid to late 14's on Cruise.

Would this statement be true for heat exchangers ( Not standard) causing fumes in the cabin?

"On boost AFR should be 11.8 - 12.2 , 10s is way too rich, extra fuel burns in the header create extra heat.
Extra heat makes the stainless steel weld bead weak and destroy the header."

Is this the sign of poor welding and choice of material? or to be expected?

Thanks

[quattrorunner]

False

[timspu]

This is what i am being told my the header supplier as to why a header has cracked.
Personally, i don't think this to be correct as normally a weld can be whole lot stronger than the base material being welded.

It would be nice to have some good info to respond with.

Thanks

TIM

[quattrorunner]

Rich mixture makes the exhaust cooler. It also depends on timing but your fuel mix seems fine. A little rich but not going to hurt the welds unless the welds suck ad the material isn't made right or supported right.
Leaner mix makes really hot exhaust gasses. Glowing headers and even turbo hot side. Welds are not effected that much with 10/1 mix. That's safe still. Have you seen your headers glow it any other outward signs of heat?

[timspu]

At night they glow but i put this down to the thin Stainless they are using.
Interesting, you are saying opposite to the supplier. Quite possibly poor material and substandard weld which could already have flaws in it.

thanks for the feedback

[quattrorunner]

Who made them?

[timspu]

Going Super Fast ( GSF headers with Heat)
At the moment going super slow because i get poisoned

[quattrorunner]

I have the OBX which I have been told are made by the same company but can't confirm. Not with heat though. Mine have been in service for a year and are still holding up. But I had an OBX muffler and the welds and material didn't hold up. I had to reweld them in various spots three times. I'd chock it up to bad build quality. At least he should replace them with another set.

[Ken911]

You get what you pay for. I had a set of those and then a set of schnell headers. both cracked after about a year. but i was driving the car every day and speed bumps in parking lots are very hard on headers. I didn't want to be spending several thousand dollars on something that was going to be bent up. Now that it's no longer a daily driver I'll be springing for something huge for the twin scroll turbo and efi i will be running.

[timspu]

Yep you definately get what you pay for, i just didn't expect the headers to leak internally. I still can't believe the fuel mixture is the cause, i think that is just a way of getting out of replacing them.

They ahave asked me to send them back and they will replace but by the time i have paid shipping and import duty its just not worth to have crap returned.
I just don't like leaving it as if the reason for the failure is due to my car rather then them admitting a fault and just sending me another set.

[RarlyL8]

Exhaust system material requirements for turbo applications are much different than for normally aspirated. Standard 304 stainless is unacceptable for long term use in the turbo environment. Asian 304 has no quality standard so pot luck. Most manufacturers use 304 because it is cheap and they can afford to replace the sets that fall apart. Proper back purged welding is also mandatory for turbo applications. If not done slag will form that can break off and lunch your $2000 turbo.
The net is full of these examples as well as the properties of 321 stainless which is much more suited to the application.

[quattrorunner]

From what I understand, this is where you should look.
rarlyl8.com

Also a cool setup is mode.
MODE : Projects | Porsche and Motorsport Engineering

B&B
B&B Fabrication Parts And Accessories For Porsche Distributed By Patrick Motorsports

[timspu]

The B+B also appear to be 304 stainless.
Will have to do lots of saving to purchase a decent set of headers.

Thanks for all the input.

[Norm K]

Originally Posted by timspu

This is what i am being told my the header supplier as to why a header has cracked.

Albert will say most anything in a effort to convince you that his headers are perfectly fine and that whatever problem you're having with them is the fault of anything except poor quality materials and/or workmanship. In my case, he blamed my inability to obtain proper fitment on my wrenching skills. Didn't matter to him that I've rebuilt multiple engines, suspensions and brake systems - even a tranny and diffferential way back when; his headers are special and I simply couldn't figure them out. It took me many months and a personal visit to Portland, Oregon, where he's located, to finally reach something approaching a satisfactory resolution.

I ultimately bought a set of RarlyL8 headers. Clever and convenient design, super easy install, high-end materials and top-notch workmanship. More money? Yup, a lot more. And there's a reason for it.

Best of luck on this.

[WPOZZZ]

Originally Posted by timspu

The B+B also appear to be 304 stainless.
Will have to do lots of saving to purchase a decent set of headers.

Thanks for all the input.

I would suggest rarlyl8 eventhough I have not used them. My B&B had cracks at the Y collector. They did fix it under warranty and even redid the heater boxes, but the repair job didn't look that great. And there was a lot of down time.

[Ken911]

Mode has oficially stopped making headers. Just got an e mail from them

[xbmwguy]

looks like i got one of the last sets. wow i actually got lucky for once!!!!!

[Ken911]

Any chance i could get you to e mail me a bunch of detailed pictures with some measurements of yours? Looks like i'll be making some.

[gsxrken]

Originally Posted by Ken911

Any chance i could get you to e mail me a bunch of detailed pictures with some measurements of yours? Looks like i'll be making some.

I'd be interested in them as well, although in my case I'm interested in the heat exchanger fab work. I already have the headers Brian sells, and the single wall collector is leaking right into the sheet metal heat box. I intend to get my collectors welded up, and now may get some heat collectors locally modified along the lines of yours now that I see that solution.

I also like the little standoff bracket to the waste gate leg. Nice touch.

[JFairman]

Those Bob Holcomb headers are now collector items and just went up in value.