KA 3" exhaust before/after dyno

[BigVinnie]

Originally Posted by S14DB

I don't see how that thread explained your point.

Well it was to help explain why closed loop is disabled or can be disabled. It isn't fully disabled either as it is still used till about 1600RPM for that specific tune.

[anyotherone]

I'm using 93oct pump gas... I'm not going to make big changes at first, because I'm trying to help out the average 240sx owner by charting the gains made by readily available parts. Most guys aren't going to go drop $1400 on an AEM when they only have exhaust mods.

When I'm done with the simple stuff I'll go all out and start tweaking things. Who knows, maybe I'll actually hit the elusive 200whp mark.

[BigVinnie]

Sounds good, I was just asking what octane you were using because (Scott)in geocities had a JWT tune, crank pulley, header and Greddy 3" exhaust. With no cams he pulled 169WHP, and 170ft/lb.s of torque using 104 octane to prevent any knock that would decrease the ignition timing. He also used the stock intake so those were pretty good numbers.
If the knock sensor is disabled (closed loop) those same numbers could be achieved on lower octanes, after all the KA's CR is under 9.6:1, I seriously doubt detonation would ocurr with that CR and 96octane. Then there is no interferance with the knock sensor at higher RPMs possibly allowing to achieve those same HP numbers. Of course with some fine tuning of the ignition and fuel maps.......
I defenitely wouldn't risk disabling open loop if infact I was running higher CR's that would cause detonation, so in this instance closed loop would not be disabled.....
Who said anything about tuning with an AEM $1400? Biki Roms are $300 and follow nissan ECCS developement. AEM EMS is reversed engineering that can sometimes be counterproductive in making BIG HP numbers, IMO many standalones are outdated and expensive once you've been taught ROM emulation, it's just more cost effective, and it SHOULD be affordable for those that just do exhaust tuning, or basic bolt ons, JWT blows.

[sultan]

i've got a 3" resonated testpipe from my s13 i'm not using, a little scraped on the bottom but will trade for cheap dyno time to see what my almost stock ka is putting down.

[anyotherone]

bigvinnie - interesting numbers... but you really can't compare numbers from one dyno to another, or really even one car to another. That dynosheet doesn't prove anything without a baseline on his car for comparison to see how much he actually gained over stock.

If bikiROM can be used to tune and it's cheaper, then good deal. What I have to tune with is an AEM EMS. Most guys will be using an SAFC, JWT ecu, or emanage to tune an S14 KA24de. What I said still stands - I'm doing some basic tuning here to begin with. After that, I'll do what I feel neccessary to make the power that I'm shooting for.

I'll post the tuned dyno runs tomorrow.

[BigVinnie]

Originally Posted by anyotherone

bigvinnie - interesting numbers... but you really can't compare numbers from one dyno to another, or really even one car to another. That dynosheet doesn't prove anything without a baseline on his car for comparison to see how much he actually gained over stock.

Agreed. But it is still a KA with a dyno sheet. True not all dyno's are the same either.

Originally Posted by anyotherone

Most guys will be using an SAFC, JWT ecu, or emanage to tune an S14 KA24de. What I said still stands.

JWT tunes for the s14 OBD2 suck all they do is remove speed limiter, there isn't any significant changes in the MAPS, and supposedly OBD2 ecu's are already as aggressive as they get for ignition timing to knock signal. Unlike stock OBD1 ECU's the stock tune is less aggressive and actual runs a bit richer, probably because of SCV's.

[redpotatoes]

Looking foward to see the dyno for your cams swap. I currently have the 248/248 setup. I want to try 248/232 and 248/240 this summer. Not sure which one is best but there is only one way to be sure. Keep on posting your dyno sheets and updates. References is always a good thing.

[anyotherone]

Sorry about asking for rep guys. I'm on several different boards, some of which asking for rep is a common occurance, I forgot about Zilvia's policy.

Cam dyno should be up shortly.

[Pank]

I wonder when people will understand that BACKPRESSURE doesnt help with low end torque. exhaust gas scavenging caused by smaller diameter exhaust tubular headers do, which helps with scavenging at low RPMs, which helps with low end torque. it is mostly dependant on the header/head design more than anything, and not much to do with the exhaust.

[BigVinnie]

Originally Posted by Pank

I wonder when people will understand that BACKPRESSURE doesnt help with low end torque. exhaust gas scavenging caused by smaller diameter exhaust tubular headers do, which helps with scavenging at low RPMs, which helps with low end torque. it is mostly dependant on the header/head design more than anything, and not much to do with the exhaust.

The 4-2-1 design is for low to mid power. A 4-1 is used for a high end power. I believe that diameter size of runners doesn't say to much about related torque though. HOTSHOTS GEN4 headers offer the largest runner diameter, and still aren't effecient to making just as much low end torque as the DC sports header, while both can still make the same HP rating(atleast what I have seen from numerous dyno results).The design of the headers splits pulses differently, especially due to runner length, and not it's diameter size.
Back pressure does play a small roll in how pulses are delivered to each cylinder, but then again we are talking under 2% is needed to regulate a smooth positive pulse.
I disagree with the use of a 4-1 on the KA after all it isn't a high rever that would utilize power to well in high RPM's (over 6500RPM).
I have found 4-2-1 headers to work the best on the KA since it utilizes the majority of it's power early.

[s13pignose]

So is it safe to say that if you wanna run a 3" ex with a header on a s14, you should replace the dummy cat with a high flow one if you don't wanna be loud?

[s13pignose]

Oh also anyone got sound clips of a s14 with header and 3" back? I ask for s14 cause s13 headers don't delete the cat from what I've read.

[ranisron]

we want more dyno charts

let's see the improvements with cams, please.

[Dopefish]

The tuning throws a variable in there... many (including myself) dont bother with tuning until most of the bolt ons have been done in N/A form. So your tuning will throw off the curve, would it be possible to do a run with the cams using your tuning and another run with the OE ECU plugged in?

I plan to go MegaSquirt with a MAP sensor soon but its not a top priority as I'd like the suspension to be tightened up a bit first.

~Kris

[anyotherone]

The header is coming off... I have to daily drive this car and it's interfering with the steering on right turns. It's dangerous.

[jp.drifter.240sx]

interfering with the steering on right turns.

is there not enough clearance between header and steering colum, or the actuall steering rack?

[S14DB]

Originally Posted by anyotherone

The header is coming off... I have to daily drive this car and it's interfering with the steering on right turns. It's dangerous.

Man, I had problems getting the OBX around the shaft. But, it cleared it easily when installed.

[anyotherone]

Sorry that I left this thread for so long. Here's the status:

The header was packaged wrong, it's for an sohc, which explains why it wouldn't ever fit right. I still would not reccomend it, it's pretty much junk.

My car is down, so I haven't driven it in almost 2 weeks, just sorting through a lot of stuff that I've been meaning to maintain or fix over the last 9 months. I have another vehicle to drive, so I just haven't spent any time on it.

Lastly, I bought an series 1 RB25det that I'm freshening up to drop in. Yeah, I decided to make the plunge, possibly going for 400whp off the bat with a GT30r. Sorry for everyone that was looking for more N/A KA dynos.

If anyone lives around Carrollton and wants to dyno their car before/after with n/a mods to continue this thread or one like it, pm me and we might be able to work something out as far as free dyno time goes in order to help out our fellow 240 enthusiasts that are looking for cheap power.

[S14DB]

I thought exhaust ports on the sohc were in totally different locations.

[BigVinnie]

Originally Posted by anyotherone

The header was packaged wrong, it's for an sohc, which explains why it wouldn't ever fit right. I still would not reccomend it, it's pretty much junk.

UUUUMMMM SOHC ports are completely different, they don't even bolt up, or are interchangeable.

[anyotherone]

You are entitled to your opinion. Johnny5 has seen my car and lives near me... pm him and ask him if I'm lying.

As far as the dohc/sohc thing goes, I have no idea, since I have never worked with sohc ka's at all, period. I'm going off the part number that was on the outer box, vs the part number on the tag inside... outer said nothing, inner said sohc. It's possible that their whole labeling system is screwed up.

[S14DB]

you try to put a S13 header on a S14?

[theicecreamdan]

there is no fitment problem for putting an s13 header on s14, the EGR stuff is at the wrong angles, but it will bolt to the head fine and clear steering components. I did it.

using hotshot headers.

[anyotherone]

I have no idea what the header is or why it didn't fit at this point.

It's possible that it is an S13 Dohc header, all I know it that it fit everywhere except the steering column clearance. I banged it with a hammer a little and thought that would do the trick, but I came to find that on right hand cornering the motor would move and it would bind... causing a potentially dangerous situation. It made power, it just wasn't worth it.

The paint immediately burnt off, making the header look like it has skin cancer too.

[weitau]

This was a good thread, I learned a lot! Thanks to anyotherone for his detailed efforts!

The only thing I would add is although a 3" exhaust clearly is superior to a 2.5", has anyone taken the weight difference into account?

A 2.5" pipe has a circumference of 7.85" and a 3.0" is 9.42". The difference is about 1.5". Multiply that by the length of the pipe, for example 118", and by thickness, 1/8" gives you 22.1 cubic inches

Stainless steel is 474.4 lbs/cu ft or .2745 lbs/cu in.

ok, so that's 6 lbs of extra weight.. not much to make a difference.

[devonkyle77]

good gain, thanks for a good post

[kenversusryu]

any more dynos with the intake and cams?

[anyotherone]

Sorry, I've actually pretty much abandoned my n/a KA power search. Too busy here at the shop to get on the dyno, lot's of personal stuff taking up my free time.

I actually have an RB25det now that I'm prepping for install, hopefully within the next couple of weeks. Should be fun, I'm planning on making 400rwhp with a GT35r and other mods on lowish boost.

[phrozen]

well i made 160hp and 147tq on a stock ka with intake and ehxuast. it was a 91ka with 200K+ miles. nuff said =D

[punkz]

Originally Posted by anyotherone

If anyone lives around Carrollton and wants to dyno their car before/after with n/a mods to continue this thread or one like it, pm me and we might be able to work something out as far as free dyno time goes in order to help out our fellow 240 enthusiasts that are looking for cheap power.

I'm in Plano so right down the street from you guys and only have an Apexi filter and Apexi GT exhaust on and would love to see where I sit at just for the hell of it. Also got that little Project Nissan cat by-pass pipe to go on and also thinking about getting and afc soon, and maybe a full exhaust system down the road since a swap/turboing the KA is something I don't want to go through at the moment. PM if we can work something out, I'm also a mod on DI (punkz32) so you can PM me on there as well