HKS Hi-Power Installed and Reviewed
 

Hey guys,

A few days ago, I got around to installing my HKS Hi-Power exhaust system I bought used from a forum member. I wanted to share my opinions and whatnot with you guys, in case you looked at getting the HKS system for your own car.

The Install:

I forgot to take pictures of removing my stock exhaust, but it's not too difficult. I first sprayed everything with Penetrating Blaster, then used a 1/2 drive breaker bar to loosen all the bolts from the cat back. In order, I removed the rear muffler section, then the mid pipe, then the y-pipe. One trick I found was that all the rubber exhaust hangers are bolted to the frame, not welded. I unbolted all of them to facilitate removing the stock exhaust easier, and then once off the car, I used WD-40 and my hands to wedge the hangers off. Much much much easier that way.

Here's a pic of the stock and HKS exhausts side by side. If you look closely, you can see the rubber hangers and their mountings next to the stock exhaust. I would also like to say that our stock Y-pipe is pathetic - the y collector was about the same size as ONE SIDE of the HKS H-pipe. Major restriction.

http://i248.photobucket.com/albums/g...426_123017.jpg

Of course, installation of the HKS was as easy as reversing the removal of the stock exhaust. I first rebolted the rubber exhaust hangers back to the car, and then installed the H-pipe, then the midpipes, then the rear exhaust sections.

Since I was working alone, I had trouble holding the H-pipe up without stressing the headers and the cats. I used a bungee cord wrapped around the driveshaft to hold the H-pipe up while I maneuvered the midpipes in place.

After that, the rear sections go on one by one, and then I just simply bolted up everything tight as possible, with a ratchet and the breaker bar. I used lock washers as well as flat washers to make sure nothing got loose or rattled.

http://i248.photobucket.com/albums/g...426_131728.jpg

http://i248.photobucket.com/albums/g...6_125213_1.jpg

http://i248.photobucket.com/albums/g...426_131731.jpg

http://i248.photobucket.com/albums/g...426_123052.jpg

http://i248.photobucket.com/albums/g...426_123034.jpg

http://i248.photobucket.com/albums/g...426_142319.jpg

The Review:

First off - let me say, this exhaust sounds absolutely amazing, albeit a tad quiet for my tastes (I am on stock cats). This is definitely how the car should have sounded from the factory. The tone is deep and clear, especially accelerating from 2k to 4k. It really makes driving the car so much more fun.

As for the noise level, it is not the loudest of exhausts, unless you cold start it. When cruising around town, you can hear it when you accelerate at 1/2 throttle or more, but it quiets down to nearly stock exhaust levels when you just maintain your speed. I consider it perfect if you wish to have a quiet car while driving normally, but loud and sonorous when you step on it. On the highway, cruising at 75, you can't hear a thing - something I consider amazing for a performance exhaust system.

On the other side, it roars beautifully all the way to redline. And dont even get me started with downshifting - you'll need new underwear if you downshift through a tunnel or under an overpass.

Also, there is ABSOLUTELY NO DRONE. Zip, zero, zilch. From every speed I tested, ranging from 0-85 mph, there was no range where you heard any resonance in the cabin or annoying drone. HKS did an incredible job with their resonator and Hemholtz tuning. Their welding is also top notch, with really thick exhaust flanges and welds that inspire confidence in a long lasting product.

Fitment wise, I would give it a 9 out of 10. Reason being, the right side physically contacts this black metal shielding that shields some rubber hoses, and when I first went on a drive, it made some vibrating noises over bumpy ground and it drove me insane. My stopgap fix for this was to wedge a rubber door stop (I'll take a picture later to show the issue) between the muffler can and the black shielding. My permanent fix will be to dremel back the black shielding a bit to give some clearance. Also, the exhaust tips are NEARLY perfectly aligned with each other - the right side sits slightly lower than the left, but it would take eagle eyes and some careful observation to spot it. I consider it pretty darn good fitment. When I get the EVO-R diffuser, the issue will not be noticeable at all.

Performance-wise, I definitely feel the boost in power and torque. The car seems to respond to lower RPM's much better, with no hesitation or anything, and up top, the car seems to be sailing through the gears. The noise also begs me to push the car hard. I did forget to reset my ECU with a battery disconnect - I'll probably be doing that tomorrow morning and I'll report back on that.

I would also like to mention this is my only performance mod - I am on stock tune, intakes, cats, headers, etc.

As for the appearance and looks of the exhaust, I personally think it is one of the best looking exhausts. I prefer the angled can design more than the stock-style muffler design. Fast Intentions was the other exhaust I debated for quite a while, but I couldn't pass up a great local deal. Sorry Tony! :eekdance:

The titanium exhaust tips are GORGEOUS. They are indeed length adjustable, and after I polished the rear sections and the tips with metal polish, I couldn't help but stare at my car's rear end like it was a pretty lady. (NOTE: Do NOT polish the Ti tips by machine - this will REMOVE the coloration of the tips. I hand polished them slowly with a microfiber towel, and it came out pristine. I took a polishing wheel with my dremel to a part of the blue burn, and it came off within half a second. Then again, I used a dremel spinning pretty damn fast, but better to be safe and use your hand!)

I won't be tuning the car until I get full bolt ons, but I may be getting a dyno done again soon to see the gains. I have a baseline dyno already of my stock setup.

**EDIT** Having recently removed the black shield on the passenger side, as well as unbolting the midsection and realigning it, the HKS exhaust sits PERFECTLY on my car. Symmetrical as could be.

That piece you are talking about where the exhaust is rubbing or hitting was suppose to be removed alltogether.

Cool write up man. Thanks for taking the time to write it. :tup:

Nice write up & pics. I'm glad you are happy & impressed with your purchase & the way she sounds now. Have fun driving around town.

In that case, I am a monumental idiot. :bowrofl: Thanks for the tip - I'll just be removing it then instead of screwing with it. In that case, I have no complaints with the exhaust fitment.

No problem! The HKS is really an awesome exhaust. Pricey when brand new, but if you get a deal or anything, I highly recommend it.

It feels like driving a new car again - the excitement is back when you can finally hear how this car is supposed to sound! I can't wait to finally get around to installing my High Flow Cats, I believe this will make the perfect volume and sound I am looking for.

by far one of the best looking exhausts for the z

^ this....

... and I think there are a set of lightly used Berk HFC's for sale on the forum right now. Jump on them, the combo is amazing!

I actually have a set of the Berk HFC's sitting in my attic, ready to install! I was forced to stop the installation on them last month due to time constraints, and me breaking 2 swivel extensions (3/8 drive set, totally useless on demon bolts.) I got around and got a whole set of 1/2 drive stuff, and I'm ready to tackle the challenge again. My school semester ends in a few days, so I might have them on in a jiffy.

Do you happen to have any videos of your setup, wheee? I would love to indulge in that combo.

I'll see what I can find... it is a very sweet setup!

Check out Linparks journal http://www.the370z.com/members-370z-...journal-3.html

He has the same setup as me (:shakes head: copycat!) and he is in Florida, might be local to you....

:iagree: definitely one of the best LOOKING

Vids!!!

HKS exhausts are typically like that - quiet on normal driving, but they respond in rapturous voice when you step on the throttle. not only the Z exhausts, but their subaru legamax systems are the same thing. the nice thing about it is that you're not howling 24/7, so less chance of cops going "wtf" as you drive by :icon17:

good pickup, thanks for the review!

It's definitely a good thing - my neighbors and cops have no complaints about the noise level. Sounds nearly stock under load. Of course, I do prefer a louder exhaust, at least louder than what just the HKS offers. I hope HFC's will resolve that issue.

Sweet, thanks weeee. Like I was saying, I'm sure HFC's will make the exhaust loud enough to the point I can really hear it windows down, and that is exactly what I am looking for.

I am very interested in doing some videos for the exhaust! It's been raining pretty much every day here in South FL, so it might be a bit. I want to get videos of cold start, warm start, takeoff, downshifts, and drive-by cruising and light accel. Should be a nice all rounder for anyone interested in getting this exhaust.

Very nice! Video clip time! :tup:

Nice review. Get HFC with it and you'll be smiling every time you hammering down the throttle.