exhaust

[TrunkMonkey]

Somebody find two back-to-back dyno charts with 2.25 and 3 in piping on a KA that proves 2.5 produces more across the entire power band, or better yet, some 1/4 mile ET's that prove 3 is better than 2.25 and I'll shut up forever.

sorry to drag this one back up, but look what i found. i know it's not back to back, but both (this dyno run and the one i posted earlier in this thread) were done with exhausts from the same company on completely stock engines.

-demetrius

[Scott McLellan]

"you can argue this until you're blue in the face":)

Let me just clarify this then: the older link was for 3 in. piping and the new link is for 2.5?

[TrunkMonkey]

first link...80mm (3.15") exhaust.

second link...60mm (2.36") exhaust.

i ran across the second link today and thought about you scott .

-demetrius

[Exar-Kun]

WINNAR!-chet

[Scott McLellan]

Okay, okay, you win. Why do Flowmaster catalogs have those charts with 2.25 up to 150hp, 2.5 up to 200hp, ect. if that is totally wrong? You must admit that that 2.36" system should have added a little power over stock. That's just weird that he picked up next to nothing. We must remember that every individual engine responds differently to mods and that is why I asked for back-to-back results (that way I don't specifically have to shut up, right?) but I figured it should have been a little closer. Although I'd still like some back-to-back results, and I'm still wondering if that 2.36 in. exhaust had a shop rag stuck in it or something, let's just say I'll be doing my "research" on this one. Hey, I don't know if you were ever in a science class or anything, but to make a "law" it takes multiple experiments with consistent results right? This was round 1. Best outta 3?

[TrunkMonkey]

Hey, I don't know if you were ever in a science class or anything, but to make a "law" it takes multiple experiments with consistent results right?

you'd be surprised at how much "law" is actually heresay when it comes to modifying engines.

science class? what's that?

-demetrius

[Exar-Kun]

Soctt: just a side note, that sounds like a summit catalog guidline, the fact is an exhaust system design doesnt go by HP, since a low displacement engine can run serious HP, while putting out (relatively) low ammounts of exhaust gasses.

side note: you will notice flex-a-lite or BLack-Magic electric fans in the SUmmit catalog listed the saem way "up to 200hp"...

its a fan, it cools a radiator, whats the got to do with the HP of the engine? Nothing, really. sure more HP, can equate to more heat, but should you use the CFM rating of the fan to determine if it can cool the radiator effectively, not the engines HP rating?

same kinda thing. sorry for the ramble.

I am going to do some baselines with my friend new civic si on a dyno near me sometime soon, and hes going to swap on 2 exhausts(an apex-i 70mm unit and a greddy 60mm I think) and seewhich exhaust nets more gains...If I can I'll post them...-chet

[AZhitman]

If anyone is still looking for flanges, I have them in all sizes (as well as high-flow cats).

Also, check the sticky on exhaust for the 240 at the top of 240 Gen Chat. Should be able to save you guys some cash on a top-quality catback.

[Scott McLellan]

Hey, I just thought of this but did that 2.36" exhaust have a hotshot? Can't remember if it said. I remember the 3.15 one did anyway. I know it said he had some ECU trouble and possibly inncorrect timing. Is there some sort of "safe mode" for 240's? I remember when my crankshaft pos. sensor (which if I understand, detects engine knock) was bad, it "seemed" like my car didn't pull quite as hard. Could it have retarded the timing to be safe costing power? Could this have also occurred during testing of the 2.36" exhaust, assuming it has a "safe mode"? I just can't see why that exhaust had basically no effect. Also, I remember seeing how for a nitrous system, it was reccomended to have a high flow exhaust for optimum power output. Why would it say this if its the same size of engine just with like 75hp more? And yeah, Exar-Kun, I have a ton of car mags (Car Craft, Chevy High Performance, Corvette Fever, Mopar High Performance, Auto Restorer, Hot Rod, and tons other catalogs like Summit and stuff. Basically anything technical. I've kinda noticed the import mags are all about stereos and lights that I really don't care that much about). And yeah, this test goes against a lot of stuff I've learned, that's why I am so suprised by these results. So for a street (not too loud) exhaust what size piping should I get? Big piping with a more restrictive muffler or smaller piping with a less rest. muff?-Scott

[TrunkMonkey]

Hey, I just thought of this but did that 2.36" exhaust have a hotshot? Can't remember if it said. I remember the 3.15 one did anyway.

neither had the hot shot header installed. they are two different cars. the second dyno with the 80mm exhaust is his "newer" car with 208k miles on the engine.

I know it said he had some ECU trouble and possibly inncorrect timing. Is there some sort of "safe mode" for 240's? I remember when my crankshaft pos. sensor (which if I understand, detects engine knock) was bad, it "seemed" like my car didn't pull quite as hard. Could it have retarded the timing to be safe costing power? Could this have also occurred during testing of the 2.36" exhaust, assuming it has a "safe mode"? I just can't see why that exhaust had basically no effect.

he threw 3 codes, none of which should have affected the dyno results considerably, and i believe alex is competent enough not to have his timing so far out of wack as to lose that much power.

-demetrius

[AZhitman]

Scott - For your car, a 2.25 system with a resonator and a very free-flowing muffler will give you the best balance of performance and sound quality.

[aspinballer]

i just dropped my resonator and my cat conv is now a "high flow" if you wanna call it something, i just put a pipe from right before where the resonator was, to into the muffler and the car sounds a bit throaty, no rice, the best ive ever heard a 4cy sound

but without a resonator it has a pop coming back from over 3000 rpms.

i cant ask for a better sound, and it breathes a bit deeper, saves me gas