laser1180

hey guys, i just got my OBX header, but now its a big debate between should i get exhasut or NOT...... well i dont want to get them because it will create noise, and my goal is to have NO excessive noise......

ok, i know exhaust (or mufflers) do not give much power anyway, but since now i have headers, the exhaust flow will be more than factory exhaust manifod... will i not gain as much power on high end as it suppose to be? or yall guys dont think it make much difference anyway?

laser1180

hmm, 9 people read this, but NO ONE can reply?

juniorbean

iTrader: (5)

won't make much of a difference considering almost every aftermarket exhaust is axle-back. The stock exhaust is very free-flowing.. so you're good there.

If you want to throw on an axle-back exhaust.. you will produce more noise, but only gain 1-4HP max.....

JasonT

I'm in the same boat. I do not want the noise of new mufflers, as well as the big pipes coming out of the bumper. Knowing a little about exhaust flow, I would think by adding headers, you increase high end power but lose some low end. You loose more low end if your exhaust system is too free flowing due to less back pressure. But again gain high end power. By changing one part of the exhaust system(headers) & not changing the mufflers, you put back some backpressure & more low end power. That makes sense to me anyway.

jimcol711

fuck the exhaust!! check my sig and look at my new 1/4 mile time, i dont have exhaust, hell, i dont even have a CAI and the OBX headers dropped 5 tenths off of my time ALONE!! i wont waste my money on exhaust, im starting to debate about the unorthodox pullies, seems thats the only other mod that might actually do something for the power of my car...

EricL

You need to consider the difference in the temps between your pre-OBX run (high temps) and your post-OBX run.

EricL

The headers help, but running at 20, 30, and/or 40 degrees makes the car run really fast. They tested a TLS at 100-degrees and it was in the 7.2-7.4 range!

14.8 at around 65-degrees F (barometric pressure unknown) [PREVIOUS]

14.4 at around 40-degrees F (barometric pressure unknown) [CURRENT]

Until you run at the same temp (65-70 degrees) with the same barometric pressure, you will never know how much the headers do for you in similar circumstances. There is a synergy going on between the headers and low temperatures; this is increased with the CAI.

HP changes about 1% for every 10-degrees F drop. That figure doesn't even take into account the additional power the CLS/TLS makes with an advance in timing (and other issues).

IMO, use about 1.6% HP gain per 10-degrees F, and use 25-degrees F of drop between runs. And, at the lower temps the stock CLS exhaust manifold is really getting "in the way" and not helping to allow gasses to get out of the out the exhaust ports. (At lower temps, the ability of the car to move air out of the engine becomes even more critical. From my own experience, the headers + CAI help more in cold weather.)

4% * 200 FWHP and/or 4% * 200 TQ is like getting a 8 HP gain and 8 lb-ft gain everywhere just from the drop in temperature.

Remember, that gain is EVERYWHERE in the power band unlike the headers...

fyud

i just installed the greddy evolution cat back and random catalytic and am very happy with it. after i got my obx headers i looked at the crappy stock pipes and had to remove that shit. not much additional noise just a deeper exhaust note. as far as power its hard to say i believe i gained a little.

jimcol711

i agree with you, the cold temperature definately helped my time, i mean, the 14.4 was my time and my girlfreind ran a 14.3...now i love these headers and KNOW they are helping in a major way, but i agree with ya on the temp. i would be willing to speculate that given similar temperatures, id be running a 14.5 or so. even still, a 14.8 to a 14.5 from just headers is still very nice. honestly though, i just dont buy into the CAI theory....

i had the Injen for about a month, i noticed absolutely no gains what so ever. the only thing i noticed was the cool sound, but to me, that was not worth the price. so i sold it, and put the stock airbox back in and left off the intake resonator. honestly, EricL, i would really LOVE to see a dyno of a car with the factory air box and no intake res. and then dyno the same car with a true CAI...i bet the numbers will be IDENTICAL within 1 hp of eachother. if anything, maybe ill throw on a K&N drop in filter or something, but i just dont beleive that CAI is all that. not to mention the worries about sucking water in.

IMO: CL-S w/ intake resonator removed + drop in filter = CL-S with CAI

but the drop in filter is 40 bucks where as the CAI is 200 +

scalbert

You ask and you shall recieve. I'm going back to the dyno in a few weeks to test this very issue along with other things. I'll be running the stock intake and then my custom box to see if there are differences.

I also want to go to see how much difference there will be between the runs last summer and now with the polished manifold, etc...

TypeSKid

I'm not sure if I'm going to ever get an exhaust if they remain to cost ~$600.


Fuck that. I can't justify spending that much just for my car to look better. 1-2hp just isn't worth it to me.

I would buy one if someone cut me a deal on it though. LIke, the most I could imagine myself going would be $400 tops!