Exhaust Flex Joints

[DB83]

Just wondering if there is a reason all the aftermarket companies don't put a flex joint into the there long tube headers where ford does have one?
I feel, if ford put one there, they must have a good reason, so i'm looking at adding them to my kooks long tubes before i fit them.

Sponsored

 

[engineermike]

I believe it has to do with thermal stresses. The exhaust heats up and expands much more than the anchor points. Also think about this….the gen2-3 has one 2-bolt flat-gasketted flange and a flex joint just on that side. Gt350/500 have that same flange design on both sides and also flex joints on both sides.

 

[GregO]

Just wondering if there is a reason all the aftermarket companies don't put a flex joint into the there long tube headers where ford does have one?

Added expense, maintaining competitive price points.
If the flex joint is handled incorrectly the service life of the flex joint could be compromised.
IMO, 304 SS systems should have flex joints. 304 SS thermal expansion is much higher than 409.

 

[DB83]

Any of you recommend good brand of flex joint to use?

 

[RagmopInKona]

Magnaflow

 

[GregO]

Any of you recommend good brand of flex joint to use?

https://vibrantperformance.com/turboflex-couplers-with-interlock-liner-v1182/

https://www.stainlessbros.com/Flex-Joints_c_52.html

 

[DB83]

Awesome, thanks!

 

[Dapepper9]

The OEM also sees a higher temp as the factory pieces hold more heat and in a smaller area. You're overthinking it.

 

[GregO]

409 exhaust tubing dissipates nearly twice the heat as compared to 304 tubing.
The OEM’s mostly use 409.

 

[DB83]

I'm going to be using header wrap too, so would rather play it safe. Definitely don't want to be pulling it all apart to fix cracked welds when I've got the opportunity to do it all whilst its off.

 

[GregO]

@DB83
Just throwing this out if you have 304 exhaust system. As mentioned in post #9 OEM 409 stainless exhaust systems dissipate twice the heat vs. 304.
Wrapping or Ceramic coating 304 /321 stainless exhaust tubing is unnecessary.

 

[DB83]

Yeah, i know it isn't necessary, but i've already got loads of wrap laying around from a previous project, and even though it's not necessary, it also won't hurt. I'm going to make sure all the steel that gets wrapped is getting coated in thermal paint to avoid it corroding due to moisture.

I'm not planning on wrapping the whole thing either, just the first foot or so of the primaries.

 

[GregO]

I'm going to make sure all the steel that gets wrapped is getting coated in thermal paint to avoid it corroding due to moisture.

Oh ok, I thought you had 304 stainless headers and exhaust.

 

[DB83]

I do. I've got the kooks long tubes, which are 304 stainless. I've heard of people have corrosion issues even with 304 stainless with header wrap as it can trap moisture if not used frequently to keep it dry, so as an added preventative i will paint them.

 

[GregO]

I do. I've got the kooks long tubes, which are 304 stainless. I've heard of people have corrosion issues even with 304 stainless with header wrap as it can trap moisture if not used frequently to keep it dry, so as an added preventative i will paint them.

You’d be better off having your headers “stainless steel cut wire blasted” if that’s available in your area.
The only corrosion issues with grade 304 SS would be from either mild steel surface cross contamination during manufacturing or exposure to heavy road salts and or calcium chloride de-icer’s

Sponsored