3" exhuast too big for KA na?

[Nissan-S14]

So you are saying you gained 37hp from an open cat.......BS Even Turbo cars dont produce that much power from an open cat. I think you might have left few very IMPORTANT things out from that dynoe. There is no way that is possible.

[stillmatic]

So you are saying you gained 37hp from an open cat.......BS Even Turbo cars dont produce that much power from an open cat. I think you might have left few very IMPORTANT things out from that dynoe. There is no way that is possible.

Actually, the car gained 26whp. I have videos, pics, and about 20 witnesses so you can call BS all you want. My motor has nothing special done to it. It's a beat up 151,000 mile KADE with stock internals.

If you want, you can contact the shop owner and ask him if it's BS. http://www.racetune.net

[ArticDragon192]

It's the increase in the advance of the timing.

[stillmatic]

It's the increase in the advance of the timing.

That only helped a little bit. A SOHC KA dyno'd at 123 to the wheels with fully advanced timing. My friend's really beat up DOHC KA with 220k miles, intake and 2.75" exhaust dyno'd at 156whp at stock timing.

[Nissan-S14]

That only helped a little bit. A SOHC KA dyno'd at 123 to the wheels with fully advanced timing. My friend's really beat up DOHC KA with 220k miles, intake and 2.75" exhaust dyno'd at 156whp at stock timing.

Is this is suppose to be one of those "jokes of the day"? Fully advanced timing? Did you turn the timing all the way? You are only allowed between 1-6 degrees on NA motor, anywhere after, man.... I hope that engine is still working. A 5 degree increase would be considered lucky if you gained 1 or 2 horsepower. So seriously stop the BS. A 500hp Twin Turbo Supra cant gain 27 "wheel horse power" from an open cat, But a 155hp NA 240sx can! SURE!!!! I have seen a lot of dyno runs and what different modifications do to cars. But you are probably the type to believe that exhaust and intake adds 50whp and stickers add another 10hp and a CF wing extra 30hp. So im not even going any further into details.

PS You know when you are stating that your friends car made 156whp, that means his car is making 156 "wheel horse power" just because of an intake and an exhaust. When a stock 240 puts about 135 at the wheels. So to proove my point (Intake + Exhaust = 20whp)

[stillmatic]

Is this is suppose to be one of those "jokes of the day"? Fully advanced timing? Did you turn the timing all the way? You are only allowed between 1-6 degrees on NA motor, anywhere after, man.... I hope that engine is still working. A 5 degree increase would be considered lucky if you gained 1 or 2 horsepower. So seriously stop the BS. A 500hp Twin Turbo Supra cant gain 27 "wheel horse power" from an open cat, But a 155hp NA 240sx can! SURE!!!! I have seen a lot of dyno runs and what different modifications do to cars. But you are probably the type to believe that exhaust and intake adds 50whp and stickers add another 10hp and a CF wing extra 30hp. So im not even going any further into details.

PS You know when you are stating that your friends car made 156whp, that means his car is making 156 "wheel horse power" just because of an intake and an exhaust. When a stock 240 puts about 135 at the wheels. So to proove my point (Intake + Exhaust = 20whp)

Hehe, I give up. You win. Comparing a 2jz motor to a KA is like comparing apples and oranges. I'll refer you to this thread http://www.zilvia.net/f/showthread.php?t=71805 and let you call it BS over there. Haha. Just make sure you have your flame suit on .

[Nissan-S14]

Well

Hehe, I give up. You win. Comparing a 2jz motor to a KA is like comparing apples and oranges. I'll refer you to this thread http://www.zilvia.net/f/showthread.php?t=71805 and let you call it BS over there. Haha. Just make sure you have your flame suit on .

Actually there is a difference, you said WHP, meanwhile the dyno is for Flywheel HP. Flywheel is reasonable, but if you were claiming Wheel horse power at 156 just with intake and exhauts thats BS. Because that means the car is putting close to 170-180hp just from intake and exhaust, compared to a stock 150hp. So you should call it whp what is actually flywheel HP

[:: orion ::]

I won't call it BS...I call it a generous dyno (as compared to the standard Dynojet 248).

Two 240SX's over 155rwhp with simple bolt on's...that is not typical.

Most I've seen on a dynojet is ~160-ish with I/H/E, ECU (w/ ~22 base timing), and pulley...but you have 2 cars with intake and exhaust putting down ~155-165rwhp...that just can't be compared ACCURATELY to a dynojet readout.

So take these results with a grain of salt...

- Brian

[stillmatic]

Well

Actually there is a difference, you said WHP, meanwhile the dyno is for Flywheel HP. Flywheel is reasonable, but if you were claiming Wheel horse power at 156 just with intake and exhauts thats BS. Because that means the car is putting close to 170-180hp just from intake and exhaust, compared to a stock 150hp. So you should call it whp what is actually flywheel HP

Actually, it's whp and yes I am pushing around 180-185hp to the fly. I'm not bsing with you. Like I said, call the shop (www.racetune.net) and ask him if any of this BS... And for the record, the SOHC guy that dyno'd his car at full advanced timing drives his car like that everyday. His motor is still fine and my motor is still running strong.

[Nissan-S14]

I won't call it BS...I call it a generous dyno (as compared to the standard Dynojet 248).

Two 240SX's over 155rwhp with simple bolt on's...that is not typical.

Most I've seen on a dynojet is ~160-ish with I/H/E, ECU (w/ ~22 base timing), and pulley...but you have 2 cars with intake and exhaust putting down ~155-165rwhp...that just can't be compared ACCURATELY to a dynojet readout.

So take these results with a grain of salt...

- Brian

Thank you, I have never seen a car with Inatke and exhaust add extra 20 whp. Well not to NA 150hp car at least.

[stillmatic]

Just wanted to clarify that my car had intake, header, open 2.5" cat, pulley, flywheel, 91 octane, new spark plugs gapped to .46mm, fully advanced timing, clogged egr, blower pointed directly to the air filter...

So I would say 160whp on a roller type dyno with almost the same mods is pretty comparable to a dynapack type since the numbers are pretty close.

[GEO]

a SOHC is NOT making 156rwhp

[stillmatic]

I thought I mentioned it earlier but the SOHC KA only pulled 123whp. 220k DOHC with 220k miles, intake, and 2.75" exhaust pulled 156whp.

[Nissan-S14]

I say we misunderstood some info, I call it truth.

[brunswick240]

So um back to the topic??? What would be better for my 240, a 2.75" cat-back, or a 3"er. I just wanna know about piping I already know about the headers, intake, and cat, and all that other jazz. Its NA right now but will be turboed eventually pushing big boost (15-17psi daily) but im building up the engine first. So what would you guys recomend so I save some money and not have to replace my exhaust twice.

[Nissan-S14]

You will never get a straight answer here, if i can only find posts now, that some company claimed 2.5" produced more power, other posts claim 3" makes more power. Just get what you look like. IMO (BIGGER IS BETTER) Thats why I went with mt BLITZ NUR-R, the sound is unfreaggin beliavable. I love everything about that exhaust, the way it looks, sounds, power and its 3.2"

[stillmatic]

So um back to the topic??? What would be better for my 240, a 2.75" cat-back, or a 3"er. I just wanna know about piping I already know about the headers, intake, and cat, and all that other jazz. Its NA right now but will be turboed eventually pushing big boost (15-17psi daily) but im building up the engine first. So what would you guys recomend so I save some money and not have to replace my exhaust twice.

You mean after all of that **** you still don't know what size exhaust to get? LOL! Anyway, I say go for a 3" exhaust with a resonator. You can get a cheap OBX s14 exhaust for less than $300 on eBay. Just gotta put new hangers to make it fit on an s13.

[skatanic28]

if i was to do it all over again....i would go with a 2.5" with a baffled muffler while n/a. all the extra noise just isnt worth the couple horsepower to me.

hopefully my n1 duals will quiet down a bit with the turbo, if not ill just make something myself.

[kamikazestorm420]

You will never get a straight answer here, if i can only find posts now, that some company claimed 2.5" produced more power, other posts claim 3" makes more power. Just get what you look like. IMO (BIGGER IS BETTER) Thats why I went with mt BLITZ NUR-R, the sound is unfreaggin beliavable. I love everything about that exhaust, the way it looks, sounds, power and its 3.2"

i got the blitz nur-r because i am going turbo soon so i didnt wanna change my exhaust when i do go turbo.

but yes .. i love everything about that exhaust too... at WOT the sound like he said is UNBELIEVABLE.

but it is a bit too loud (for the cops, not me) to drive around in CA at night

[4gotn1]

hey i have an ebay 3in exhaust and i love the way it sounds. its the kyo brand. and it has taken a beating cus my car is lowered but its holding up, over a year. its crazy sounding with my sohc, i also have a 2.5in test pipe and obx header. its really loud at WOT. but its the best sounding exhaust i have herd in along time. i have a sound clip of my car just being revved if anyone wants to hear it. it sounds like my car is turbocharged at idle. it was also not running right and it blew a 12in flame out the *** end.

[Chaotic_Warlord]

it was also not running right and it blew a 12in flame out the *** end.

I don't care who you are, you have to admit there is nothing cooler than that... I am still up in the air on which exhaust I want...Apex'i N1 or Blitz Nur-R, both sound awesome, both are well respected and both produce solid results HP wise. I hate making choices, in the end it will come down to which one is cheaper . I think as far as sizing goes I'll go middle of the road and run with a 2.75" as I don't know how long it will be before I can turbo my car. Oh and Id love to see that video, try to find someone to host it, want to see you shoot that flame.

Oh yeah BTW when I found my car I was initially there to look at a rebuildable 96 S14 that was in a wreck, if it hadn't of had a huge gash in the R rear 1/4 panel I would've taken it. Anyways the exhaust broke off at the header when they either loaded or unloaded it off the flatbed, let me tell you it was sooooooooooo loud just sitting at idle, 5 feet away it sounded like your ear was an inch away from the exhaust on a Harley.

[keepingthe240]

I don't know of any company that makes a 2.75 catback I have an apexi n1 (3 inch) i'd sell ya. THe shipping is a killer due to being a one piece. Your looking at $400 shipped

[4gotn1]

i got a clip but with no sound of a little fireball being blow out the ***. its a short clip taken with my buddies digital camera. pretty dark but you can deffinatly see the small fireball.

as for the sound clip ill try and zip it up or convert it to mp3 or something because it about 2megs as is.

[Dattebayo]

You know thats the one thing im starting not to like in this forum.

It seems that one cannot trust any information posted in most of these question threads. I cant belive anyone would believe this DOHC putting down that much ANYWHERE. And im not even a NEWB hater around here. I dont care what anyone says, the machine was not operating correctly to make those numbers.

BTW, the clip doesnt work.

[4gotn1]

ok here is the sound clip as promised, it was converted to a mp3 format. i warning it is loud and if you have headphones on you might want to turn them down. its my car reving to 7000, and its a sohc.

[dfw240_EE]

My studies have not been much in fluid physics, but here is what I do understand about exhaust. As was stated earlier, exhaust velocity is key to performance. An engine at a certain RPM will produce a certain volume of exhaust within a set amount of time (I have heard the units cfm, cubic feet per minute).

The venturi effect states that velocity of a gas passing through a confined space (like a tube, ie exhaust pipe) is inversely proportional to the cross sectional area. Mathematically, v = f/a, where v is velocity, f is flow, a is area.

The narrower the space, the higher the velocity. Too wide of a pipe, too low of a velocity, and turbulence will form and cause it's own sort of back pressure. This is why big exhausts rob low-end power, I think. The flow just isn't coming out of the engine at a high enough rate for acceptable velocities.

A narrower pipe will yield higher velocities, but higher backpressures (due to the fact that gas has mass and friction with container walls?).

I do remember that the engine's flow rate is proportional to engine size and RPM. With the KA24DE being such a large and relatively rev-happy 4 cylinder, it would stand to reason that there would be fairly high flow rates needing a larger exhaust than say the old 1.5L D15B2 I used to drive. Further a largish exhaust would de-emphasize low RPM and move the power band abit closer to the redline (as opposed to our listed peak at 5600RPM)

That post went longer than I planned. I am done for the night.

[Nicksemianiw]

HAHAHAHA i had my Apex'i GT spec exhaust on my KA24E on my old 240 and the GT spec is 3.78 inches and i dident have any problems lol.

Nick

[Chaotic_Warlord]

ok here is the sound clip as promised, it was converted to a mp3 format. i warning it is loud and if you have headphones on you might want to turn them down. its my car reving to 7000, and its a sohc.

Dude you weren't kidding about that being loud, and I love the commentary and the little horn beep. Oh and the starburst at the end...nice, I love it. Has anyone else listened to the clip yet, is that about how loud the Blitz Nur-R is? Very impressive, 2 thumbs up.

[180fan]

Stillmatic, as good a tuner as Frank is, I don't think he could get that much out of a stock KA from just an exhaust. It'd probably be a combo of the two. It's not entirely impossible to get good gains from just an exhaust and intake alone on the KA. Example would be Alex's (of 5zigen) dyno of the 5zigen Proracer Aspec on a otherwise stock KA.

http://forums.freshalloy.com/u...art=1

But to put it all on the exhaust and a few bolt ons, I'm a bit skeptical. Probably a combination of a few things though.

Back on topic though, 3" is not too large for the KA.

Also, different types of dynos can give pretty different numbers. Hence alot of controversy over "which dyno is best"

[4gotn1]

thanks everyone i have passed has claimed it sounds like an indy car from hell when i beat them. i personally love the sound, and its an ebay exhaust system. its a knock off! ill get some pics of it some time. it does hang pretty low. but i have only scraped it when i have been going really fast and hit a bump, my car is also lowered, i have eibach sportlines and kyb gr2.