A community of enthusiasts dedicated to Nissan's SR20DE/SR20VE/SR20DET engines.
Start here: forum search. Be sure to search on what you're looking for before posting a new thread.
You are currently browsing the forum as a guest. In order to access special features, the image gallery, and post you will need to be a registered member. Registration is fast, simple and absolutely free so please, join our community today!
If you have any problems with the registration process or your account login, please contact the administrator.
Okay guys, I have a friend who recently puchased an S13 with the KA24DE. He's looking into the Apex'i GT Spec exhaust, and in the future, is looking for a DET swap. The question is, if he were to get the GT Spec exhaust for the KA, would it still preform well on the SR?
well you need back pressure on N/A motors so you might loose lower end tourque in the KA but definetly gian high end power. and well on the SR he will defiently perform well as no backrpessure on Turbo motors is god like. He shoul dhave no problem blowing nice flames if her gets the DP adn test Pipe as well.
An exhaust on a SR? bahaha just do as i do and just run a downpipe! Nice, Loud, and lets the turbo spool nice and quick! Plus no O2 sensor makes for some nice fireballs hahaha.
__________________
1993 Aztec Red Nissan 240SX Fastback - SR20DET Powered
The Apexi GT Spec exhaust is not a true 3.74" or 95mm piping exhaust!
It starts off as 75mm at the flange where it bolts up to the cat, then expands to 85mm just before the muffler, then coming out of the muffler it turns into 95mm for like a foot maybe, then goes into the shiny can.
The only reason for that is to exhance the sound, nothing more.
If you know the ideal gas law, then you would know that the step up in piping diameter does nothing for flow (at least not the way they did it, maybe if it started off being 95mm then eventually stepping down to 75mm or something).
The Apexi GT Spec exhaust is not a true 3.74" or 95mm piping exhaust!
It starts off as 75mm at the flange where it bolts up to the cat, then expands to 85mm just before the muffler, then coming out of the muffler it turns into 95mm for like a foot maybe, then goes into the shiny can.
The only reason for that is to exhance the sound, nothing more.
If you know the ideal gas law, then you would know that the step up in piping diameter does nothing for flow (at least not the way they did it, maybe if it started off being 95mm then eventually stepping down to 75mm or something).
okay, this meaning it's not a good exhaust for the SR? I'm sorry, I'm just relaying the info.
I didn't say it wasn't good. It's actually one of the best exhausts out there for the money.
However, some of Apexi's exhausts have questionable welds, as their older N1 exhausts will rust and crack where the welds are, from the mild steel to stainless steel joints.
Their new exhausts are all stainless though, so that problem shouldn't still exist, however, because the exhausts are now all stainless, the cost for them also went up.
If you don't mind the loudness, check out GP Sports exhausts. I have their Spec D catback, which has mild steel 80mm piping (slightly bigger than 3"), no muffler, with a huge N1 can at the end acting as the lone muffler (perforated resonator type muffler), so it's pretty loud. However, it's very tough, which is a good thing for me since I'll be slamming the car here soon, so the exhaust is gonna get owned hard.
But in the end, it all depends on what kind of exhaust you want. Quiet, loud, all out performance, etc.
well you need back pressure on N/A motors so you might loose lower end tourque in the KA but definetly gian high end power. and well on the SR he will defiently perform well as no backrpessure on Turbo motors is god like. He shoul dhave no problem blowing nice flames if her gets the DP adn test Pipe as well.
-Juantons
Umm no. you don't need back pressure on n/a motors. you want zero back pressure on all car motors. you're confusing back pressure with flow velocity. back pressure will make any n/a car slower at any rpm. smaller piping flows more are at lower rpms but will not flow as nice up top due to the restricted pipiping and vice versa for larger piping. larger piping has a hard time scavenging unill higher rpms
I love the observation that although it has been claimed that an infinite amount of monkeys with an infinite amount of typewriters would eventually produce the complete works of Shakespeare, the internet has proved this is not true in the slightest.
Umm no. you don't need back pressure on n/a motors. you want zero back pressure on all car motors. you're confusing back pressure with flow velocity. back pressure will make any n/a car slower at any rpm. smaller piping flows more are at lower rpms but will not flow as nice up top due to the restricted pipiping and vice versa for larger piping. larger piping has a hard time scavenging unill higher rpms
if the smaller flows less/is restricted at higher rpms then that = more backpressure. And yes there has to be compromise in piping diameter for drivability on road-going n/a engines. too big and you have no torque, no backpressure, and you will eventually blow seals. So what bardabe said is right. Sorry not trying to jack the thread, just making sure the facts are right.
__________________
Poor with big plans.
Black 240SX. Suspension before power.
Support Innovation! Buy from companies that design their own parts.
if the smaller flows less/is restricted at higher rpms then that = more backpressure. And yes there has to be compromise in piping diameter for drivability on road-going n/a engines. too big and you have no torque, no backpressure, and you will eventually blow seals. So what bardabe said is right. Sorry not trying to jack the thread, just making sure the facts are right.
wrong. you need flow velocity. no car motor needs back pressure to function. you need a scavenging affect. you are confusing back pressure with flow velocity
^hes right... but on a larger motor like the ka, running a 3" doesnt lose power. There were dyno's and sh*t to prove it on zilvia. Buy a 3 inch exhaust. GP Sports is what i have... 3in, straight back, no bullsh*t diameter changes.
^hes right... but on a larger motor like the ka, running a 3" doesnt lose power. There were dyno's and sh*t to prove it on zilvia. Buy a 3 inch exhaust. GP Sports is what i have... 3in, straight back, no bullsh*t diameter changes.
yeah here guys look at it this way. if you were to run a motor without an exhaust at all according to what hte other guy said. it would blow up. what people need ot realize is that exhaust doesn't add power at all. every exhaust robs power from the motor. some just rob less power at different areas in the rpm band. in an ideal world, you wouldn't run an exhaust at all.
All I know is my GT Spec sound so bad ass! ... and some nice flames!
__________________
I have mastered the art of breaking sh*t!
6 motors down ... 1000's more to blow!
93 240, BlackTop, s14 turbo, Power Fc, Greddy intake manifold, pullys, Apexi GT Spec turbo back, Fever Racing turbo manifold, PWR intercooler, Koyo radiator, Spec stage 3 clutch, Nismo GTS LSD with fluid cooler, Tein HE, and so much more
i dynoed my stock KA with 171k on it, and I made 120hp to the wheels with the stock tiny exhaust. I bought a 3 inch fujitsubo, and got a new cat (OE replacement cuse my A/F readings were out the door at like 10:1 on the dyno), and the car made 129hp. Not to mention the car drives much much smoother now. Before it felt like it had too much torque down low, and it would lurch around in 1st gear and climbing up through the gears you could feel where it stopped making horsepower. After bolting the exhaust up, it revs freely, and there is a nice smooth powerband all through the gears.
And Im keeping the car N/A. I could care less about no backpressure downlow, because its going to spend its time beyond 3000rpm.
wrong. you need flow velocity. no car motor needs back pressure to function. you need a scavenging affect. you are confusing back pressure with flow velocity
yeah that is if you wanna keep[ blowing seals and what not all the time and rebuild your motor all the time. here is a little piece of mind I wish to share with you guys about exhausts systems on N/A Cars. or exhaust in general.
For both turbo and N/A cars, backpressure is unecessary and bad. Less backpressure=more hp and tq. Here's the best answer to the age old question that I've found.
The commonly accepted backpressure theory is wrong, but backpressure does exist. In reality, you want as little backpressure as possible. Having as little backpressure as possible will give you more hp and tq in all rpms, but bigger piping can INTRODUCE backpressure into your exhaust system because of increased turbulence from not enough flow. Just like piping that is too small will restrict flow and not allow enough air through. It's not about the backpressure, it's about the flow.
Running no exhaust at all isn't very helpful either because of something called the "scavenging effect," where exhaust that is already flowing through the tubing sort of helps "pull" exhaust that is just leaving the engine. Dumping exhaust straight to the atmosphere from the block doesnt allow for that... thats why most dragsters have exhaust manifolds and short lengths of exhaust tubing. The exhaust can be tuned so that the inertia from the exhaust pulses pulls the next beat out of the engine.
The best example I have for disproving the 'back pressure needed for TQ' arguement is F1. F1 cars are most likely the most expensive, most researched cars on earth. F1 cars have a wide range of rpms that the engine revs through (since courses can include long straightaways as well as hairpin turns). F1 cars have near-perfect exhausts which create only about 1-2psi (normal cars have approx 18-20psi) backpressure (0 is ideal, but impossible unless you are in a vacuum). So why would the top racing cars in the world only have 1-2 psi if back pressure was needed for low end torque?
so for my slamming conclution. F1 motors are rebuilt all the time after every race. so if you wish to do the same. go right a head and get a 3.75" exhaust for your N/A car.
in other words
Quote:
Originally Posted by Drag_300
well I can tell you that on an na you do need back pressure. On an na with no bp you risk long term valve damage. You can use most of the motor tech for building v8's but not all of it will work on a motor that could potentially have a 11000 rpm red line! The VG30 makes power on a longer rpm duration. Running no bp would severly hurt your low end power. Now you are right to a certain point, a little less bp will improve your power, but if you go too far........you lose hp. On the realistic side of this, you would have to have a custom header with 3" runners and a 4" straight pipe all the way back no can or converter, or open headers to get anything close to an f1 car. One other thing f1 cars are running sick compression compared to your car, and you dont rebuild you motor after every race! Ive seen a lot of RnD work in japan with a lot of different cars to find the best pipe size and it seems that a 70-75mm pipe made the best power and torque. Thats only about a half an inch larger that the stock pipe on your car. You also have to take ecu tuning into account!
__________________
juanton: I swear dude
juanton: if this girl becomes my gf
juanton: I am shaving that sh*t
mark: haha
mark: just lick it man
mark: gotta start off hairy
mark: so you can feel way better
mark: when it's shaved
