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Just got back from the exhaust shop from having the turbo HKS exhaust installed on my naturally aspirated 3sge. I found a couple of threads on the UK forums but there wasn't much information on it. This was entirely for experimentation/curiosity. I didn't want to butcher the HKS B-pipe as I plan to turbo sometime. The HKS B-pipe overlaps with the headers before they merge into one. I had a simple 90 degree bend adapt to the stock B-pipe with a welded flange and the shop also mated the stock exhaust to it too so I can revert back if it is too loud. We couldn't find gaskets so I will order some from japan sometime.
So this will be a completely subjective assessment. I can't imagine having police/warrant issues in the slightest with this setup. It is obviously louder but very far from big bore honda civic levels. At idle it is hard to hear any difference from stock until the A/C increases the idle. There is not much of an increase in noise in the cabin during acceleration or town cruising with partially open throttle (windows up). With the windows open it is significantly louder. Coasting or decelerating with a closed throttle has noticeable drone with windows up. I have yet to go open road but I am guessing it may not be the best. I am pretty picky with exhaust noise but I would imagine most people would be very happy with the noise levels. I got one tiny bit of rasp when leaving the shop which I couldn't replicate again.
I will update after more driving. There is definitely more power/torque which is not surprising with a 29 year old catalytic converter removed along with a somewhat restrictive exhaust.
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Nice mod. Very simple to adapt which is cool. Still needed to hack your B pipe though. I managed to create a custom length decat pipe for mine.
For loudness, the turbo is a muffler on its own so the NA could be louder than the turbo. I know my 3SGTE TRD muffler is louder than when it's on a turbo engine. Although I do like it when really going for it, it pops and bangs when getting on and off throttle.
No buzz. It sounds amazing at WOT and has made a huge difference above 4000rpm in terms of power. There is pretty much no rasp at all just bassy drone. I try to idle out the drive past neighbours. I will put the old one back on later this week. It will be very handy going between them for when I get a downpipe made. I can sort each piece at a time while having a normal driveable car.
That's good to hear. Do you have a second NA B pipe as you have cut your current one.
One other thing I noticed was the smells with no CAT. More fuel and oil smells. Oil smells will depend on the engines condition obviously.
It's cool to compare the 2 different mufflers and see what frequencies they help control.
Here is mine, about 10 seconds after a cold start at around 1000rpm. I want to get more of the car from inside and outside. Keen to hear yours too.
I did cut the stock B pipe just after the lower cross member but I had them weld in a flange and mate it back up to the stock exhaust first. Then make a small bend to mate with the HKS so I can swap between the two exhausts whenever I want, no new b pipe or welding required. Just undo a couple of bolts, swap exhaust and it's done.
I did it this way just in case it was too loud and I could immediately go back to stock. I haven't had the best luck with custom exhausts and noise control in the past. I'll try and do a video.
How is a silencer supposed to install? This sounds like a stupid question but I wanted to see if a silencer would make a difference. I measured the bore on the muffler about 5 times, it is 115mm (unless I am an idiot). I then ordered an HKS 115mm silencer as I thought this would guarantee a good fit. It is smaller than 115mm by up to 10mm. Is it supposed to sit loose? I know tighter ones can rattle, maybe it is supposed to be like this?
I would have to take it out again to measure but I would guess about 110mm which they don't make anything near that. The only other sizes I can see are 94mm and 120mm.
I found this on their website, I have the "115mm universal" (bottom right) which I thought was a sure thing. Seems that it actually is 110mm and the site above states it is for any HKS with 115mm tip... weird but I don't have much experience with this. Maybe I need to go for a drive and see what happens.
Alsw20 wrote:My old one used to fit snug inside the tip. Needed a special tool (old piece of rebar with a small hook on end) to remove it.
Thanks for the advice. Did yours make a noticeable difference to the noise?
There is no doubt this is the correct item shipped but the wrong one ordered by me. With a little bit more research I could have avoided this but I think their website description is misleading. I assumed 115mm would have to be the ID of the exhaust tip since you are shoving something inside it and wall thickness varies. Looks like I need to order the 120 Drager tip as below
Yes, mine was almost silent. I had 3” Aussie downpipe, 3” mandrel bent mid section and N1 muffler, 3” inlet, 5” outlet. The silencer turned the muffler into a 1” exit.
