Am I the stupid one here, or is he??
 

On ********, I had made a post about what the exhaust that I'm getting sounds like, and this guy is arguing with me that a 3" exhaust is better for an N/A ka24e then 2.5". He said this:


"No, it isn't anywhere near too big for NA. It's been dyno proven that
a 3" exhaust gains from 13-15whp on a nearly stock naturally aspirated
KA24DE, whereas a 2.5" exhaust on a KA24DE with the same other mods
gains only 7.5whp.

You are wrong, and backpressure is not a good thing."

I had said that 2.5" is deffinitly enough and that 3" is just too much, I'm just confused here now. Am I wrong or is he?
:dunno: :confused:

either works fine, not that big of a difference. i have dual 2.75" pipes on my apexi, tq and butt hp are definently stronger in lower and higher rpm's. i would go with a 3" personally, usually will sound deeper too.

whoever you'ret alking to is a moron. 13-15 just by a 3" exhaust? LMAO

he must have a Tornado and an E-Charger too

Let me guess the guy debating with you must of been (Insanity Inc)......
It sounds like something he would say.....

I would pay no attention to him, he has no dyno charts of his own.....LOL I also argue with him every other week, so who cares......
There is not enough room in the power band to make 14WHP with exhaust alone. Under the SAE NET the KA engine produces 155 HP, this rating is given through power from the ecu and all applicable bolt on's.
There was a dyno a few years back in fresh alloy where supposedly this bone stock s13 with only a apexi N1 exhaust made 14WHP. Technically that is not correct info. The ecu was throwing codes, It needed a new thermostat, (who knows what kind of errors the engine will have during OPEN loop as well), plus the engine was dead cold!!!!!
That is just a way of manipulating HP numbers, and I don't find 14HP believable, that means against all odds without the 15% degredation that the 240sx makes with the drive train, the exhaust alone it made 19HP at the crank without any other modifications.The catylitic converter holds back soooo much pressure that flow wouldn't even move fast enough through the 3"exhaust to even matter if it was 3" or not......
Don't listen to most of the crap you hear.
2.5" is fine and will help maintain a healthy power band....

yup...thats him. hahahaha. Ok, I figured 2.5 was enough. Thanks guys! Oh, and I wont be taking what he says to heart anymore ;) lol

My exhaust is bigger then 3 inches.. so tell me, am I kicking out 50 hp with it or something?

I really don't care about HP on the damn exhaust. The deep throat sound is hot.

damn, what size exhaust do you have?!

My tip is 4.5 inch and the exhaust is 2 1/4 from the cat back.

Picture

http://www.pix8.net/pro/pic/11393W8fOY/511499.jpg

I'm talking about from the cat to the muffler size, not the size of the muffler/tip. My muffler is gonna be 4.5" also.

Oh.. ok! :)

Thought you meant something else.

i have 3 inch pipes out to a 4 inch muffler i feel power its what you perfer 2.5 or 3 not that much different id go with 3 its jus me

actually my muffler is bigger than 4 like 4.5 or something

There's a dyno chart somewhere, too lazy to find it but I will later, that had stock number, then numbers after a 3" apexi n1 or similar was installed.. and there was a 12hp peak gain I believe, and no losses at all, in TQ or HP. ..

I believe we are talking about the same car. Here is what you guys don't understand about the inacuracy of that dyno. The THERMOSTAT was bad, that means engine tempratures rise with NOX, they ran the engine cold, and there was an exessive amount of fuel dumping. There was also a AEM CAI used which nobody ever mentions either. That means the car wasn't smogable or streetable for the conditions it had on the dyno. It was even admitted by the owner of the car.
Can a 3" make just as much top end power if not more than a 2.5"? Yes, but if you were going to compare the differences in all reality a 3" would only probably produce 1 additional HP over a 2.5" in top end power. The reduction of back pressure wouldn't matter so torque numbers would relatively stay the same (due to the catylitic converter). 3" is just to freakin loud for streetable conditions. If you do infact run an exhaust system without a catalytic, then you run into scavaging issues which will decrease HP and lose torque in the low end, and eventually decrease fuel.