How many times have you cracked your hks manifolds?

[nismo-152]

Just curious if everyone has to deal with this problem on a regular basis.
Its now the third time i have cracked along the welds on both my low mount hks manifolds.
Seems about every 20 hard laps and they need to come off for a welding. New welds always hold but continue to find new places on the factory welds to crack...

[hp44incgtr]

yup its very normal for this hks thats right i keep the stock i mean its not that funn pulling the turbos out everytime to weld an crack mani..

[Skym]

Cracking happens due to exhaust moving left, right, etc (look at gearstick moving left to right and right to left when cornering to see what I mean). Most put a flexi in front pipe (similar to what is done on Honda's) to help prevent the cracking (less weight swinging on engine) and fit some bracing to support turbo's.

I noticed on Gibson R32 GTR Group-A racecar they added custom braces over top of engine, which I assume helps with stopping this problem (helps to take the weight off the exhaust manifolds).

Other option is a custom thick walled steam pipe exhaust manifold with thick flanges (6boost, Sinco, etc). And or fit a lighter titanium exhaust (weighs something like 4kg vs 20kg+ for mild steel aftermarket or stock exhaust). I think stock exhaust was around 24kg last time I weighed it.

[bkkn]

It's exactly why I ended up sticking with ported factory manifolds. I had bought a set of well made stainless ones but didn't have the time or patience to fabricate support brackets properly. I as well didn't want to end up pulling them back out if / when they cracked.

[Skym]

I noticed Nismo use ported stock exhaust manifolds on N1 engines.

Gibson R32 GTR Group-A racecar braces (over top of engine) can be seen in these photo's -

http://www.speedhunters.com/2013/02/godzilla-attacks-the-gibson-group-a-gt-r/

[nismo-152]

I may have no choice then but to support them better. Already running factory supports,flex pipe and a lighter exhaust. As much as i love steampipe log manifolds ill try this out first. Thanks for the link to the Gibson photos Skym.