Ive tried searching this forum and looked all over google but i am unable to find the answer. I know the HR exhaust system out flows the DE. But i was wondering if The HR cats also out flow the DE cats. i might be picking up a cheap set of stillen headers for the HR and dont mind the extra work of swapping the studs. I wouldnt mind hfc or art pipes but i like how quiet my HKS exhaust is until i open her up. Plus i cant stand a "raspy" exhaust.

So basically do Hr cats flow better And is the inlet/outlet dimensions wider? Thank you

 

Well if you go with stillen HR headers you have no choice but to go with a HR cats or test pipe. HR headers don't bolt up to DE cats/tps and vice a versa

 

I understand that. just wondering if there would be an advantage over stock cats. Thanks though

 

ah I have both at my house I can take pictures for you...if anything

 

Pics would be nice. Or measurement of inlet/outlet diametert would be easier.

 

That's true. The flanges on HR cats are bigger than the flanges on DE

 

Wait.. I'm confused. Are you asking if there will be a power gain from switching stock cats to high flow cats/test pipes...?

 

No no no - he is making the assumption (which I agree with) that the HR exhaust flows better than the DE exhaust, and with that assumption, does that mean the HR cats flow better than the DE cats…

My answer is no, I don't have hard facts on this but I have had HR cats and DE cats right next to each other and the HR cats did not seem any bigger or too much different in shape or capacity..


HRs on the left / DEs on the right

 

Beat me to it...obviously it larger!

 

The problem is Nissan engineered the HR cats to match the amount of backpressure needed for that particular engine. Swapping them over to a DE simply won't help- the ECM will adjust for an anomaly in backpressure and output will remain the same (while throwing a CEL at the same time). It's a familiar story...