My exhaust is HKS with random technology HFC. is it better to run my exhaust with a test pipes instead of HFC?

 

Do you have some sort of visual emissions inspection where they look for catalytic converters?

If you wanted test pipes why did you install catalytic converters?

 

What do you mean if it's better?

Like performance-wise? Sound-wise? What does "better" correspond to?

 

performance wise

 

i had the hfc on before the hks exhaust

 

Of course test pipes will perform better.

The question you should ask yourself, "Is it worth switching to test pipes?" Let's say you do switch, how much horsepower do you think you will have gained? Will you be able to notice that marginal increase in power? Will you like the exhaust sound after the switch to test pipe??

I think the HKS sounds like crap with test pipes but that's just me.

 

^ I agree I had helix test pipes paired with the hks and it sounded terrible, I now have crawford hfcs and I think it sounds great! Plus I couldnt tell the difference between tps and hfcs.

 

Stay with HFC's... Switching over to test pipes will give you a SMALL gain if any over your current setup but will sound raspy. I wouldn't do it personally. Just my .02...

 

I love having test pipes with my HKS. No rasp at all after the car warms up.

It will be much louder though, than with the HFC's.

 

Once I had a Berk non resonated test Pipes with my HKS then I switched to Crawford HFCs because of raspy sound. Non-resonated tps will give raspy sound. Try with resonated test pipes. You will be fine then

 

Resonated Test Pipes = No Rasp FTW

 

The difference between the two will be small/un-noticeable. Like David said, if they are going to look under your car for cats then I'd advise against it. Take it from me, I started out with test pipes with my hks hi-power and it was way to loud and raspy for my taste. I since switched to berk hfc and am quite satisfied.

 

thanks all, ill stick with HKS + HFC.

 

I disagree. Test pipes you will loose power 2k-3.5k (rough estimate) With any test pipe there is no back pressure wich will cause the exhaust to free flow out. You need back pressure to keep low end power. IMO if its a DD you want to go with HFC. TP will gain a LOT of power up top that's why people for for it.

HKS does sound like crap with tp

 

^^

Sure they lose a tiny bit of power down low, but that amount is made up for by the large increase you gain for the rest of the curve..

And I have seen dyno's of people not losing any power after switching to test pipes..

 

Well said.

 

Also worth saying is most HFC dyno so close to test pipes now a days with 300-400cell cat setups there isn't much point (other than cost). Plus remember with out a cat the car is polluting as much as 30 cars does. I'm not a tree huger by any means, but all that pollution for 2hp? Just doesn't seem worth it really.

 

So you guys are saying that there's no rasp with HFC's right?

 

^^^ i don't have any RASP now with HFC but when i was running TP i got lot of rasp.

 

Correct.