turbo exhaust on NA

[SilviaDriver]

i was wondering..does a turbo exhaust on a NA setup car..open up for better high end? cuz dont u need high end for 1/4 drag?

[tnord]

if our engine could spin faster than a gerbil wheel then maybe, but it doesn't, so i doubt it will

[SilviaDriver]

well..not really turbo muffler..but if u go with a bigger diameter..wouldnt it open up for better high end..of course u would lose power at low end n everything for daily driving..but at the track..wouldnt that bigger diameter..lets say..2.75 or watever or higher..juss making up numbers..make better for high end? i know ppl who go with 2.5, dats y i used a bigger number like 2.75.

[mazdog240]

I don't know how it would effect performance but from what i've heard the big (usually 3") turbo exhaust setups are insanely loud on an NA, so just keep that in mind.

[kandyflip445]

I don't think it would do you anygood, unless you plan on going to turbo, to get a turbo sized exhaust(3" or bigger). The whole point of having a 'tuned' exhaust is scavenging. When an engine is on it's exhaust stroke it pushes the spent gasses out of the cylinder. When the gas is traveling through the exhaust piping it creates a kinda vacuum(can't think of a better work). That 'vacuum' pulls the rest of the spent gasses from the cylinder. That is why people ceramic coat headers and such also. Hotter gasses move faster, which increases scavenging. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>

~Zook

[AKADriver]

I know of naturally aspirated fours that make good use of 3"/80mm exhaust systems.

But just bolted onto a stock KA... don't bother.

[Boromir]

I thought the Apexi N1 was made for a turbo engine, and plenty of people use that on their n/a 240's (including me).

[Kreator]

Uhhh well, some people like their cars to be loud and slow... no offense

3" is way too much for a n/a ka. e.g. at the peak performance its not going to be pushing enough to make use of all the 3 inches. On the other hand, since you have larger area, the speed of the exhaust gas is much slower, thus loss in torque.

[s13cruzer]

so what can be done to make up for that low-end power loss when you get a turbo/na exhaust , i have the N1 dual , and it said it works for both na and turbo , i did notice the low-end decrese but wanna make up for it somehow

[Kreator]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (s13cruzer @ Sep. 16 2002,01:10)</td></tr><tr><td id="QUOTE">so what can be done to make up for that low-end power loss when you get a turbo/na exhaust , i have the N1 dual , and it said it works for both na and turbo , i did notice the low-end decrese but wanna make up for it somehow</td></tr></table><span id='postcolor'>
take the mechanical fan off.

[s13cruzer]

....and put in an electric one? , is it that easy to increase low end power?

[Kreator]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (s13cruzer @ Sep. 16 2002,10:39)</td></tr><tr><td id="QUOTE">....and put in an electric one? , is it that easy to increase low end power?</td></tr></table><span id='postcolor'>
Well, it's going to give you like 4-5hp except unlike intake and exhaust it's gonna be the low end (your engine is being robbed when it's trying to spin up the fan). From what i heard it's effective from like 1000 to 3500 rpms. Should give ya back all that u lost with the exhaust. I got one, but since my engine died that same day, i haven't tested it out yet.

[MasterOFDrift]

So you can remove the fan attachedto the engine to gain an increase of power? do you have to replace with a mechanical fan or can you just leave it fan less. I live in a pretty cold/mild climate. also how do you take off the fan any how tos on this?? I've been trying to find this for a while

[Kreator]

Well the mechanical fan is what u have right now. You take that off, and now your engine doesn't have to spin up the fan when u are just starting, what will cause the engine to rev faster and give the horsepower used to spin it up back, cuz theresn't as much resistance.

Go to www.240sx.org and look at installs section. I think they have directions for setting up an electric fan and taking off hte mechanical one. It's not that hard. You shouldn't run into any major problems mechanically. To set up the electric system, you got to tap into the ignition/fuel pump wire, so the fan starts up when u start the car.

When i got mine, i replaced both the ac and the mechanical. I think the fan i got pushes enough air to replace both.

If you live in a cold region, it's probably enough to just take it off, but to be on a safeside, put the electric one in. If you are going turbo though, electric is a must.

[tnord]

in case you didn't understand the previous post, i'll toss this up for size.

any accessory drive mechanism's contribute to the parasitic losses of the engine. hence why there is a discrepency between engine hp (at the flywheel) and wheel hp (at the ground). removing the mechanical fan reduces this gap in power, as would taking off your AC, changing pulley's, lightening driveshaft.........etc.

[Kreator]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (tnord @ Sep. 14 2002,12:24)</td></tr><tr><td id="QUOTE">if our engine could spin faster than a gerbil wheel then maybe, but it doesn't, so i doubt it will</td></tr></table><span id='postcolor'>
You meant this one? I thought you were reffering the rpm and power thing. Meaning that our engines don't produce enough to actually make use of 3" piping even at max output.

Hmm so you basicly saying that taking of the mechanical fan would give rwhp, but the flywheel numbers will stay the same? makes sence, but won't the flywheel numbers rise just a little bit? Cuz it's actually is lighter and would produce more power from the amount of fuel burned...

[240 2NR]

Depends if they tested flywheel horsepower with or without the mechanical fan attached. &nbsp;In anycase, the fan is a pretty substantial parasitic loss. &nbsp; I know in first gear you can feel the disengagement during acceleration. &nbsp;At the same time I think it will only engage in 1st and 2nd gear and only below certain speeds, so at freway speeds it's not an issue. &nbsp;I believe Alex Chang had a write up for using only the electrical fan, and eliminating the mech one. &nbsp;He claims to see little difference even in traffic in california between the water temps with the mech or small stock electric fan (but don't wuote me on it, I read his post several months ago, but he does detail how to wire this up).

As for the gerbil wheel comment, I think he was saying if the KA spun to around 8k, having a larger exhaust for a worthwhile top end would be meaningful. &nbsp;Considering the power drop at 6k you're more likely to benefit from the top end, midrange and low end gains (or lack of loss) with a ~2.5," than to hope for any very minimal gains at only the "top end" with a 3" plus exhaust.