Danwolski

Buying a HKS single. What would be the advantages of buying a test pipe or HFC to go with it? How would the sound change? And what do you guys do for emmisions?
Also are the rumors of the HKS losing power true?

Gernby

The rumors about power loss are about the HKS dual. You will not lose power with the 3" single.

If you budget would support it, you should consider installing a Gern-Pipe with the single (see signature). If not, then you will definitely get gains from a test pipe or HFC. The gains from a test pipe would be almost as large as what you would get from a Gern-Pipe, but you will have lots more drone, soot on the bumper, bad exhaust smell, and it would be illegal. The HFC would help with the smell, soot, and legality, but performance would be signicantly lower.

Danwolski

Id get it but it would cost me more than the exhaust, and I can't really afford that right now. So adding a HFC or test pipe would make it sound worse because of the drone right?

Gernby

I haven't tested the HKS single, but I suspect that it would have less drone with a test pipe than an HFC. I haven't even looked at one in a long time, I so I don't know if it has the side branch duct in front of the resonator (aka weiner pipe), but if it does, then it would drone less with a cat.

jjaypal

I have HKS single with Berks 3'' TP. Drone is not bad at all. Ive had this for about a month and already am used to the louder exhaust. It has a great sound as well. Just know if you have 06+ S that you will need an anti fouler or another angled piece (dont know name of but if you search forum you will find), or else you will see the CEL, i have still yet to install mine.

Gernby

If you have an '06+ with a test pipe, and don't have a FlashPro, then you're really losing out! The gains from the exhaust and test pipe with the stock tune are nothing compared to what you will get from the addition of a tune. FlashPro also allows you to simply turn off the secondary O2 sensor.

s2000ellier

buy flashpro before you buy any other mod

Danwolski

So if I get a ap1 will I have a CEL? And I have a ap1 so no flashpro

!@#$%

I have the 70mm hfc, and it's a great piece. Fitment was 100%, no cel, made stock exhaust more audible, and doesn't stink up the joint. It gives off some soot on the exhaust tips, but other than that, I'm highly satisfied not having a rattling clogged oem setup.

I don't mind losing a couple hp I'll never feel from having a tp anyway. I love being able to just take my car to inspection without any extra work.

Danwolski

Thanks for the review, what brand HFC(fixed) do you have? And do you know if I have a 75mm HKS should I use a 70mm tp?