This is actually the MAP Short Runner which I believe is identical to the GT Spec. When bought it, I knew there was a good chance that it would eventually happen. And it did. The weld heat affected zone where the cylinder #1 runner connects to the flange cracked. All the other welds look good, so I'm going to have it repaired and put it back in service.

 

That's too bad.

how did this exh mani compare to a ported oem unit?

aby

 

Isn't this a regular occurrence with steel?

OEM piece is cast iron to mitigate wear caused by heat cycles IIRC.

 

I think the flow path is smoother than stock or ported stock, and the tubing size is plenty large. I can't imagine another stock frame manifold that flows better than this one. The only minor drawback is that its not a true equal-length header, and that it seems inevitable that its going to crack.

Yeah, I suppose. Its more common in the cheaper manifold. A proper post-weld stress relief heat treatment with the manifold attached to a jig would help, but I don't think anyone bothers with that.

 

Maddad, gt spec and a bunch if others are all the same piece rebranded.

I had a gt spec for my Subaru. It's of the better quality of cheaper stuff I believe ..

Post pics of repair!

 

Do you have a power & boost ramp up compare between the gt spec & ported oem?

 

I never had a ported OEM. Two tubular manifolds I tried a few years ago didn't do any better than stock. I think gains from any aftermarket manifold depend heavily on how hard the turbo is being pushed. If turbine backpressure is high (always for me), I think that gains from a manifold will be minimal.

 

Thanks for sharing, Mychailo!

I am running the same thing with ceramic coated, so I guess all welded manifolds are subject to this problem only matter of when.

Mine is also bought from MAP, and MAP always provides great customer service, I hope they can take care of this one for you.

As far as I know this short runner is a HKS copy, and it is sold under many different brands.

So far satisfied with the result especially considering its price and availability.

 

Im not sure if map would replace it. But it looks like a cheap fix.. Or look for a vendor that warranties their work.. i think toxic fab does..

 

Thanks. Its already been repaired and is back on my Evo. English Racing welded up the crack and then faced the mating surface which was pretty badly bowed when I took the manifold off my Evo.

 

I was actually saving up for a map short runner. Was hard deciding between the short and long runners, but if warranty is an issue, maybe other companies manifolds hold up better?

 

do those guys perge when they weld with nitrogen

 

The MAP/GTSpec Short Runner is pretty well made. Note that the crack did not occur in the tubing but in the HAZ region on the flange. The flange had a pretty good bow when I took it off the car, so there was a strong force trying to pull the cylinder #1 and #4 runners out of the flange. I think the cracking could have been avoided if I had removed it after a few months of use, and then faced the flange flat to remove any bow that develops. For people who rely on shops for all their mods, its obviously not economically attractive to do this, but for the DIY folks, it is something to consider.