Hey I was reading some posts on Fast Intentions Resonated Hi Flow Cats (RHFCs) and I plan on getting some. I've done reading and found that HR headers can be used with the DE motor assuming HR OEM or aftermarket cat/test pipes are used because of the different header-cat flanges between the two setups. Is ANYONE running running OEM HR headers on a DE motor WITH Fast Intention Cats? When I called FI, I talked to Kevin, and he wasn't sure this was possible. He said the bends on their HR RHFCs are slightly different than the DE and couldn't guarantee me 100% fitment.. I've searched all over, and it seems as though the few people who do have HR headers on their DE motor are running OEM cats (a few) or they are running HR TEST PIPES. I've not come across anyone running Fast Intentions HR HFCs with HR headers on the DE motor. Could anyone confirm if this is possible (ie, you or your friend actually did it)?
Thanks in advance!

Also, I am well aware of the minimal gains from DE to HR headers and the associated pain of the install. Only reason I'm considering this set up is I got the HR headers for free and I'm getting a new motor and so the old one needs to be pulled anyway.

 

I think you will gain more than you expect, the DE headers are literally awful. Everybody rants how they are not worth changing out but they most definitely are.

No way did they run HR headers with DE cats, the flanges are different. The HR flanges are larger like you said, must make it easier to replace them.

If you read it somewhere other than where I said it (I read that too somewhere) I would say you are good to go as long as you pick up HR cats or test pipes.

 

[QUOTE=yosip1115;7021425]
"No way did they run HR headers with DE cats, the flanges are different. The HR flanges are larger like you said, must make it easier to replace them."

Not what I meant, sorry. I meant I've only heard of guys running HR headers with OEM HR cats or aftermarket HR TEST PIPES, not DE stuff. I'm thinking I may just go with the DE RHFCs since they're sooo $$$ and I'm not 100% sure they'll fit. Sucks since I'll have the motor pulled anyway and I got a set of used OEM HR headers. Kevin at Fast Intentions said the "bend is different" in the HR and DE version of the RHFCs so maybe the resonator somehow makes them not fit. I think they'll probably fit, but I'm not $640 sure which is why I wanted to know if anyone has definitely done this before.

 

I have HR manifolds with FI resonated test pipes. Fits fine.

 

Everything I've read says you need to use HR cats/hfcs/test pipes when using HR manifolds. Of course the "bends" are different because the HR manifold "ends" at a different spot. HR cats/hfcs/test pipes are a little bit longer.

 

Yeah, that's what I thought, but I just stuck with the DE stuff. Didn't want to chance it...