NA exhaust ???s (HKS Hiper+)

[KLR142]

Sup guys, my friend is replacing the exhaust on his 91 240 KA24DE... We're getting a catco 2.5" cat, and are now trying to figure out what we want to get for an exhaust. We really want something that's pretty quiet, but 2.5" in diameter as well... There's not much out there off the shelves that fits that very well... The closest thing is the HKS Hiper 65mm exhaust, which seems like a pretty good exhaust. We want the 65mm piping instead of the other 60mm systems that are out there because we want something that'll be good enough for a stock SR swap that'll come in a few years... I know something bigger would be better for it, but price-wise and current performance wise something in the 2.5" size would be good.

So, whaddaya all say?! And does anyone have any pictures or vid clips of the Hiper exhaust or others installed on NA KAs? Let's see and hear'm! Thanks!

[nissantuner22]

get the 3 inch. better gains now, better gains with the SR.

[sticky240]

i dont think their is much difference in price from a aftermarket 2.5" & 3" system, its just what size you want.

anyways, over on NICO forums, their are some people who like their BRM exhausts. Check it out

[hurleyboi514]

i run the 65mm exaust. i like it b/c its not super loud until your on the throttle, so its nice and quiet below 2 grand. i could probably make more power with a 3", but i dunno if i want the noise...

[KLR142]

Originally Posted by nissantuner22

get the 3 inch. better gains now, better gains with the SR.

I know... And I don't want a three inch, like I said in the original post, for reasons such as noise, and lack of optimum performance with the KA, which will be in there for more than two years at the least before we get an SR. So again, NO 3"! I'm basically looking for some pictures of the Hiper exhaust and wondering what people think of it who have it. And also, if you can think of an alternative, something that might be quieter than the Hiper, but still larger than 60mm, because the Hiper will flow well enough for an SR in the future. The 65mm piping and the exhaust design, is, I'm sure, much better than the exhaust that an SR20DET would come with stock so it'll still be an improvement for the SR swap as well as being the much better choice for our current setup. When we get hardcore into the SR mods, which won't be until quite a few years from now we'll think about switching up to a 3" exhaust, or if need be, a 3.74"...

Sticky240, thanks, I hadn't heard of them before. We'll check it out!

Originally Posted by hurleyboi514

i run the 65mm exaust. i like it b/c its not super loud until your on the throttle, so its nice and quiet below 2 grand. i could probably make more power with a 3", but i dunno if i want the noise...

Hmm, do you have it equipped on the KA? If we put a 3" on the KA as we're planning to keep it(stock, although it does have some intake mods and it IS the best KA24DE ever available, as in it has the hottest stock camshafts...), it won't be as good a performer as the 65mm exhaust, and it will definitely be too loud. The 65mm will probably be louder than what we're wanting, but we may just have to make it work anyway. Do you think it would be under 95db on a KA???? Do you have any pictures? Thanks!

[019]

actually a 3" (80mm) exhaust will make more power than a 2.5" (60-65mm), which is what everybody has been saying. the only downside is the noise. i have the 65mm hiper on my car and i love it. it's nice and deep and very quiet around town. and yes, i have it on my ka, as does hurleyboi514. i'd probably recommend getting a 3" exhaust that is quiet like the rsr exmag

[Teb74]

019 or Hurley I would love to see pictures of the HKS Hiper on the car if you could post some that would be great!

[KLR142]

Originally Posted by Teb74

019 or Hurley I would love to see pictures of the HKS Hiper on the car if you could post some that would be great!

^^^ This kid ^^^ would be the owner of the 91 240 we're discussing here... So yeah, can we get some pictures of these exhausts installed?

O19, the RS-R could be something to look into... But, I HIGHLY doubt that a 80mm exhaust on a stock KA would be beneficial. If the KA had some headwork done and some cams and ECU work to match, I'd believe it, but stock, very hard to believe... People "say" stuff, but it doesn't necessarily mean that it's true. If you can prove me otherwise(dyno sheets, etc.) I'll change my mind... If you can prove to me that the 80mm RSR would be quiet on a KA, then we might consider it in respect for the SR in the future. How is it so quiet compared to the others? Is it just larger chambers and sound dampening in the mufflers? Or do they use louvered core or baffled mufflers? If they do, F that, we want flow...

So pictures and proof anyone?

We're doing this to finish off a set of mods and improvments to allow this car to pass emissions and make some more power at the same time... Too bad we just dynoed the car a couple months ago with the worn out everything... We'll just have to go back again and see how big of a jump we get...

[RBS14]

Quit being so damn stubborn!!!! 3" makes more power and torque than 2.5". Period. Backpressure is bad for any engine, including N/A. Scavenging is more effective with 3" on ka, simple as that. If you want 2.5 for noise reasons, that's one thing. But you will not gain as much power.



That's Mav1187's ka before and after 3" exhaust. I've NEVER seen gains like that with a 2.5" exhaust on ka. Guess why? RESTRICTION! is that proof enough?

If you are uneducated enough about 240's and cars in general to ask a question such as this one, maybe you should listen when people who know what they are talking about tell you how it really is....

[019]

here's a pic of mine


an 80mm exhaust will give you more gains than a 60-65mm exhaust on the ka. alex chang has dyno'ed the 5zigen pro racer exhaust on his ka. a gain of 12 whp from JUST an exhaust. afaik, he doesn't have any headwork done or ecu. read about it here: http://forums.freshalloy.com/ubbthre...e#Post67651483

as far the rsr exmag exhaust on a ka, i have yet to hear it, but i do know it is pretty quiet. halo on this board has it on his sr, just search for it. he has a video clip as well.

[twong85]

Yes its true you'll see gains in hp and torque across the whole power band with an 80mm exhaust. As for the exmag with ka24de, its not super quiet but its also not horribly loud. I think it only bothers me after 4k rpms. Oh yea and after the exhaust ages a little the tone gets pretty damn deep.

[KLR142]

Originally Posted by RBS14

Quit being so damn stubborn!!!! 3" makes more power and torque than 2.5". Period. Backpressure is bad for any engine, including N/A. Scavenging is more effective with 3" on ka, simple as that. If you want 2.5 for noise reasons, that's one thing. But you will not gain as much power.

That's Mav1187's ka before and after 3" exhaust. I've NEVER seen gains like that with a 2.5" exhaust on ka. Guess why? RESTRICTION! is that proof enough?

If you are uneducated enough about 240's and cars in general to ask a question such as this one, maybe you should listen when people who know what they are talking about tell you how it really is....

See, there you go, being wrong... It doesn't make you look very good. This is why you don't see more of me on this and many other forums... There are people like you on them who think they know everything, and not only about cars, but about other people as well. I speak with a great knowledge, and some experience, but NOT on a KA24DE. If you look at the dyno sheet you posted, it's OBVIOUS that there was some problem with the "supposed" stock exhaust dyno run... Switching exhausts isn't going to fix that F'D UP curve. There was something else done at the same time, or something at least done in between the runs or there was some other problem beforehand...

Backpressure is bad on any engine, yeah, no shit, but, a three inch exhaust most likely won't be able to keep the exhaust velocity up to help the scavenging of a stock KA... One person's dyno sheet(that in itself doesn't prove crap because of the errors with the car on the "stock exhaust" run) doesn't prove anything about two similarly designed high flow, perforated core, mandrel bent exhaust systems. What exhaust did he have on it beforehand? Was it some cheepo 2" crush bent sub-stock standard system? And other crap? One dyno sheet that has problems won't convince me of anything except the car was previously f'd up.

Stubborn? not THAT much. Educated? absolutely. Not experienced specifically with the characteristics of a bone stock KA24DE and comparing two similar exhausts? Correct.

We need an exhaust that will look good on the car, will pass emissions sound requirements, and flow well enough to support a stock SR20DE. And yes, a 80mm would easily be better than the 65mm on the SR even stock, but we, I repeat, need something that is quiet, and won't hinder the performance around town of a stock KA at the same time. If we can get more "so called proof" that a larger system will work and not be too loud, then we'll do it. So give me more proof and don't start saying I don't know what I'm talking about. If you start questioning that and giving me shit, well, don't plan on me listening to much of what you say being the idiot that you're acting...

[KLR142]

Originally Posted by twong85

Yes its true you'll see gains in hp and torque across the whole power band with an 80mm exhaust. As for the exmag with ka24de, its not super quiet but its also not horribly loud. I think it only bothers me after 4k rpms. Oh yea and after the exhaust ages a little the tone gets pretty damn deep.

Do you happen to know how loud it is in db? Have you gone through emissions with it?

[KLR142]

Ahh yes, and it also makes tons of sense that most of the aftermarket exhausts that are specifically for the NA KA models are 60mm...

[Salty_X]

Actually that's the wrong dyno sheet, which is why they all say stock at the top. IIRC Alex had a bad coolant temp sensor which was causing the funky powerband.

This is the dyno RBS14 meant to show you: first run is completely stock with a cold air intake, second run is with the addition of a 3" exhaust.



Don't worry about smog, exhausts aren't smog devices. If you have vehicle inspections though you need to see if giant cannon exhausts are legal.

[KLR142]

Originally Posted by Salty_X

Actually that's the wrong dyno sheet, which is why they all say stock at the top. IIRC Alex had a bad coolant temp sensor which was causing the funky powerband.

This is the dyno RBS14 meant to show you: first run is completely stock with a cold air intake, second run is with the addition of a 3" exhaust.

Don't worry about smog, exhausts aren't smog devices. If you have vehicle inspections though you need to see if giant cannon exhausts are legal.

Thanks for the clarification and something that actually makes a little more sense... And regarding smog, I'm just talking about sound levels, they check that in our area as part of the smog testing. And, do you know specifically which exhaust this is? And how loud it may have been after he installed it? Those are some impressive gains. I can't wait to see what we bump up to from our worn out 121hp... Thanks again!

[RBS14]

My bad, yes, that is the dyno I meant to post.

I'm not trying to get into a pissing contest with you.

I'm the dumb one and you think a CATBACK exhaust is going to affect emissions? riiiiight. Wow, I'm soooo sad I don't see more of you on here, I really miss seeing topics like this that have been asked and ANSWERED many many times. You may be educated, but not with cars. What you are failing to realize is that the displacement of our engines is high enough that it warrants a 3" exhaust. So do you think a 2.5" exhaust would be optimal on a rb25de? 2.5l vs. 2.4l. people think since it's a 4 cylinder that it must not need/benefit from a large exhaust. You are wrong, along with all the rest of said likeminded people. Why ask a question if you don't like the answer? <- rhetorical question if you couldn't figure that out.

[Salty_X]

He used a 5zigen Pro Racer, which is a basic N1 style exhaust. Since you're concerned with noise, I wouldn't buy it or any other 3" except maybe the RSR Exmag (not the Exmag GT2 though). Once you go SR it would be tolerable, but with the KA.. no thanks.

Even Alex said this about the exhaust: "With this exhaust (and without a silencer) it is unbearably loud and causes headaches and pain in my ears after ~20 minutes of driving. For power only I would suggest an exhaust like this; for your average street car I strongly recommend an exhaust that is more quiet. IMO the power gains are nice but the car becomes a huge police magnet, especially in areas where noise level output is enforced."

And I believe he's been pulled over a few times for noise violations...

[twong85]

Yes this has to one of the most beat to death topics of all the 240sx forums out there. 3" exhaust is pretty good for our 2.4L engine so theres no point trying to argue it. And RSR Exmag isn't as quiet as people make it out to be on the KA24de(its made to be quiet on a turbo car). I mean it isn't an n1 or ProRacer but it sure ain't stock either. If you plan on flooring it...it'll be loud. If you drive conservatively it won't catch TOO much attention. Oh yea and one of the reasons many of the exhausts for the ka24 are 60mm is due to the noise issue that come's with large piping on NA motor.

IMO you should just go buy a 2.5" if you're so concerned about noise.


o yea here's a sound clip of my exmag on a 91 ka24de. I rev'ed once to 3000 then to 5500~6000. http://www.bol.ucla.edu/~twong85/MVI_1293.avi
Keep in mind this is inside a parking structure.

[019]

didn't anybody click on the link i posted? it has an explanation of everything as well as the dyno that salty posted...

[twong85]

I think most of us have seen it before. I still remember when I first saw the post on FA last year when I was deciding on which exhaust to buy.

[019]

well to know that know, yea, obviously. i just meant to the ppl wanted to know or brought up that thread. salty posted the dyno and info that was on that page, which ppl should've seen... whatever... everyone can see now

[S14DB]

I had a 60mm 5zigen Fireball. It would max out at around 5000rpm. Even with the silencer it was louder than the 80mm Cannonball I have now. The 60's may have lower dbl N1 to N1. but the 80mm has a larger resonator and muffler which lowers the tone. Even thou the dbl on the 60mm N1 may be lower. The lower tone of the 80mm N1 makes it seem quieter.

If you are concerned about sound I would not go with a N1 style exhaust. I would go with something like a RSR ex mag.

I'll be dynoing the Cannonball this weekend to see the results. As far as streetablity the 60mm is a myth.

[theicecreamdan]

I like my apex'i with no resonator, its just really deep.

[Salty_X]

Originally Posted by 019

didn't anybody click on the link i posted? it has an explanation of everything as well as the dyno that salty posted...

I did. It just seemed like the threadstarter missed it, so I brought some of it into the thread.

[nightwalker]

btw, a 3inch exhaust makes a different type of exhaust note. It's more of a deep bassy hum than a raspy higher pitch exhaust note that you hear with most import car exhausts.

[KLR142]

Originally Posted by RBS14

My bad, yes, that is the dyno I meant to post.

I'm not trying to get into a pissing contest with you.

I'm the dumb one and you think a CATBACK exhaust is going to affect emissions? riiiiight. Wow, I'm soooo sad I don't see more of you on here, I really miss seeing topics like this that have been asked and ANSWERED many many times. You may be educated, but not with cars. What you are failing to realize is that the displacement of our engines is high enough that it warrants a 3" exhaust. So do you think a 2.5" exhaust would be optimal on a rb25de? 2.5l vs. 2.4l. people think since it's a 4 cylinder that it must not need/benefit from a large exhaust. You are wrong, along with all the rest of said likeminded people. Why ask a question if you don't like the answer? <- rhetorical question if you couldn't figure that out.

Read my post right above yours... (smog/exhaust topic that you're getting your balls all fukked up in)

And educated with cars i am, shiit man, take a hike, you aren't helping at all. Grow up and stop trying to tell me what i know about cars because you have no clue. Damn, kid. And i'm not likeminded like the fukking people you're talking about, see, you're FUKKING WRONG! Now shut up and take your pointless nagging somewhere else, you did your deed, plus what you didn't need to.

And just so you can't pull the any more BS on me, i used the search function. And I can learn more about it and get better comments than the newbs who have asked the question before.

RBS14 PEACE OUT!
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And yeah, Salty_X, you're right, i didn't click on the link originally because i didn't have time to in between my classes. I just scanned what was up real quick.

twong85, thanks for the link, and randomly enough, i've seen/heard that clip before. I can't deny that it sounds good though, but yeah, it'd definitely be too loud.

Thanks guys, I agree that the N1 style is going to be too much, I just wanted to make sure... And the one we're considering, the 65mm HKS could also be too loud... But, I don't know. Research needs to be done. Thanks for the help so far! Peace

[twong85]

Originally Posted by KLR142

twong85, thanks for the link, and randomly enough, i've seen/heard that clip before. I can't deny that it sounds good though, but yeah, it'd definitely be too loud.

errr wtf?!?!?!?! I took my cannon powershot out and made that vid TODAY!!!! That's how MY KA24de with exmag exhaust sounds TODAY!!!! The only other clip I've heard is of Halo's when it was first released in the US and his is on an SR20det. Iono maybe you have seen the clip before.....see the future maybe?

[KLR142]

Originally Posted by twong85

errr wtf?!?!?!?! I took my cannon powershot out and made that vid TODAY!!!! That's how MY KA24de with exmag exhaust sounds TODAY!!!! The only other clip I've heard is of Halo's when it was first released in the US and his is on an SR20det. Iono maybe you have seen the clip before.....see the future maybe?

Lol, I guess it was just another sexy 240 in a parking garage then... That's the part that i remember anyway... And might I say again, it's NICE!

[fliprayzin240sx]

If youre going for quiet, then your best bet would be Greddy.