I have read that the HKS Hi Power is really restrictive if I go FI.. But could it be any more restrictive than the stock exhaust and why is it so restrictive? Also will it still make the nice deep sound compared from NA to FI? Which exhaust has a similar deep sound like the HKS but its made for FI? I know it's a lot of noobie questions but after doing a lot research nothing that I'm really looking for is coming up.. Thanks~

 

question i'd like answered also.


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I have the Hi-Power and will be keeping it for my InlinePRO turbo build next week. The exhaust is NOT best suited for an FI application, but frankly, I want to keep sound down. I'll have to run higher boost levels and cope with a slightly longer spool up time but I think it will be worth it for the lowered sound levels. If your aren't going for all out max power and don't mind being a little innefficient, I see nothing wrong with the Hi-Power.

 

I'm CTSC'd and I have the HKS. I dyno'd 287 to the wheels. I'm not saying I wouldn't make a couple more HP with something less restrictive, but I don't think it'd be much at this boost level. Unless you are running big boost, I can't see how this exhaust can be that restrictive. I wouldn't sweat it, mang. Spend your money on actually getting to FI.
As far as sound, I think my exhaust sounds perty darn good.

 

I'm not sure how the Comptech Exhaust compares with the HKS, but with my Comptech spool up isn't bad at all IMO. I do have a relatively low boost setting (12 psi) but I love how the car feels.

In terms of sound... the Comptech was quiet to begin with, but after the Turbo it got even quieter.... BUT it has been getting louder. I think the significantly hotter exhaust gas temp has been burning up and taking away the sound deadening material in the mufflers.

 

anyone think the HKS would make less hp then the stock exhaust would running 9 to 13 psi? I've heard the Hks looses power on a stock car. I can deal with not gaining anything by bolting this exhaust up, but wouldn't want to loose hp just for the sound.

 

I use to run the same setup, but with a turbo it sounded as quiet as stock. Forget about keeping the sound down, it won't make any with the turbo acting as an extra muffler. Hopefully you will like it better than I did.

To the OP, are you talking about going turbo or SC'er when you are asking about using an HKS exhaust for FI? For SC'd applications it should still sound great. It definitely won't help you make the most power that you could, but the sound will be nice. With a turbo, it will sound like stock unfortunately since the turbo quiets it down that much.

 

When I first went turbo I was still able to make 330whp @6psi with the "restictive" HKS, so i'm not sure if its as bad as everyone makes it out to be. However, when I went over to a 3" single I gained 12whp (although I dyno'd in the middle of the summer when the first runs were done during the colder winter so it might have gained more), and with the HKS I was only boosting 6psi when the WG spring was a 7psi spring.

 

As XA said it depends a lot on what kind of FI you're talking about. For SC, the restrictive exhaust doesn't have nearly as much impact as for turbo.

If you're going SC then stick w/ the HKS. It'll cost you a few hp but nothing drastic. If on the other hand you're going turbo, it's kinda silly to spend all that money and lose performance b/c of your exhaust. A 3" turbo exhaust doesn't have to be mind-numbingly loud.

My exhaust has a nice deep rumble. It's loud but not that loud. It's a 3" inline pro single w/ a a magna flow can welded on (the can from inline was unbearably loud).

 

buy a Cutback for the sound and dont bother with Hp.
IOt doesnt matter that much in the end....the best exhaust is the one you can live with...
A good one will make you enjoy the car more and love to push it and a bad one will make your head bigger.
Better sound is with a Supercharger than a Turbo. thats for sure.
For me sound is what counts. i will post a link later if you want of a SC sound clip with supersprints and a testpipe.
Go with the HKS i am considering of getting them just to try them out.