don't think it would do shit since we don't have a turbo, it would just cause excess noise. cut-outs are mostly for turbo'd cars

 

yah but wud it work instead of having a cat-back ?

 

don't think it would do shit since we don't have a turbo, it would just cause excess noise. cut-outs are mostly for turbo'd cars

not true, cutouts work well on V8s and such...I was actually wondering about this cut out idea today also...

I didn't know if anyone was running an electric cutout on their RH or something...

Someone here made like 8 hp gains over their RH by running just open header so gains are feasible.

 

so if some1 made an 8hp gain, then it mayb be worth keepin the stock exhaust in place and placing a cut-out on or right after the race header .... if sum1 has this setup please chime in. Im trying to keep a stealthy look, while with a flick of a switch, open headers with more power possible.

 

YOu will lose horsepower cuz an N A car needs back pressure i was thinking of getting an electrical cut out on my turbo rsx

 

I've had it in my RSX-S when it was boosted and it was wonderful. It was attached to the downpipe which allowed me to use the stock exhaust. Right after the kit was installed (CN1 back in Jan 04) I dyno'd at 281whp @ 8lbs with the stock exhaust on. Later on, after my engine blew and was replaced with a stock short block and the cut out installed, I made 315whp @ 8lbs. The cutout itself was a lot of fun b/c it catches a lot of people off guard, plus allowing you to avoid any stupid exhaust tickets. This was my experience with a boosted car and I've never heard of running it with an NA car.

 

i know NA cars run cut-outs but they were V6's and 8's. SO i was wondering if it could do something for the k20A2? It would be much cheaper and less attractive to cops to run with a cutout rather than exhaust being loud all the time.

 

Has any1 ran open downpipe ( cut-out after race header ). I was wondering if this would yield great gains. You keep a stealthy look by keepin your stock exhaust put you just open the cut-out and you have open headers. I was thinking maybe i haven't heard it because no1 has done it becuase its not a good idea. thanks

you might end of running lean Air to Fuel Ratio if you do

 

YOu will lose horsepower cuz an N A car needs back pressure i was thinking of getting an electrical cut out on my turbo rsx

Nice 3rd post...its probably good to know what you are talking about before you post though...

Backpressure is a bunch of bullshit, it actually robs you of HP...the more free flowing your exhaust is the more power you are going to make.

http://auto.howstuffworks.com/muffler5.htm

 

the more free flowing your exhaust is the more power you are going to make.

:thumbsup:

If you do a strait pipe from the header then you will make more power but is it worth making maybe 15 Hp to risk getting caught and getting a $2000 fine. This is not a new idea, it is more popular on V8's for things like drag but it will work on a 4. You also have to take in consideration where you get your sticker for your car. If a shop suspects that you drive it on the street and not on the track then you may not get a sticker or they may make you takt it off. It all depends on how much of a prick you get (with getting pulled over by the cops too)

 

so backpressure is not neccessary? Therefore, a straight pipe is the same as open headers ? Therefore, cutout is beneficial. I thought people would have this done, but i guess not.

 

most backpressure is a myth.

 

http://www.team-integra.net/sections/articles/showArticle.asp?ArticleID=47

this article addresses piping size and backpressure.

 

so with that article in mind, backpressure is not needed, so open headers would be ok im assuming ?

 

so anyone have any conclusions on effects of a cut-out?

 

effect on 5psi supercharged RSX betwen DCRH+stock catback and DCRH open header via cutout is <10hp. on a n/a car, the effect is even less.

 

even if the cutout will give me the same results as a cat-back staying NA, i think it is worth it to keep the stock exhaust, and having open RH. Surprise a lot of people! Keep a low-profile with cops.

The question is will open header produce same, less, or more HP compared to a RH w/ a cat-back?

 

without tuning, open header will produce extremely lean AF's.

compared with a good catback exhaust, open header should produce minimal if even measureable gains.

 

alot of open ended info in this thread.

Back pressure isn't the "enemy"....too much back pressure is bad, but you need some for scavenging to take place. I'm not going to take the 20 minutes it would take to type up all the reasons why but look at the team-integra articles....IMO they explain things pretty well.


lat-R

 

you will loose torque and HP at low to mid rpm and wont pick up enough to make it worth it on the top end with a non FI motor if you dont actually make less powr with the cutout.

granted my experience with this is with v-8 NA cars but they actually made my 70 mustang slightly slower in the 1/8th.

 

i'm not trying to be an ass or undermine anyone but most of the time when someone says backpressure what they're thinking of is delta pressure. back pressure is caused by an obstruction when delta pressure is caused by resistance. like krystar said the a/f ratio will become an issue being too lean

 

I've had it in my RSX-S when it was boosted and it was wonderful. It was attached to the downpipe which allowed me to use the stock exhaust. Right after the kit was installed (CN1 back in Jan 04) I dyno'd at 281whp @ 8lbs with the stock exhaust on. Later on, after my engine blew and was replaced with a stock short block and the cut out installed, I made 315whp @ 8lbs. The cutout itself was a lot of fun b/c it catches a lot of people off guard, plus allowing you to avoid any stupid exhaust tickets. This was my experience with a boosted car and I've never heard of running it with an NA car.

u have to live in Nova and had work done at B&T Motorsports, atleast if you had an NPB Type-S that was turboed, i wanted to do a motor swap with a dude that was selling his turbo kit off his boosted Si Block there....


To address the cutout: I think i'm the guy that the thread starter is reffering too. My cutout is mounted off the down pipe right before the cat, i have the stock exhaust system. i dynoed 9whp above my line while it was closed, when the cutout was open. interms of cutouts on turbo and s/c applications, it all depends on what your exhaust is like before you measure it against the cutout. if you have a high flow and large diameter exhaust and mount a cutout, it may not show that much a gain, but when you design an exhaust to run on a cutout when you want it to, it will show the greatest gain short of just header period. depending how you mount the cutout (i just recieved the comptech shorty header today and am going to have a custom downpipe made to mount the cutout straight down from the header's collector) it will increase your hp a little, or ALOT. if you consider how much volume of exhaust it expells right away vs a 3" (huge) catback and the length it takes vs a 3" cutout, there is more flow right away. Torque is the only thing affected by Back Pressure (or delta, whatever), and with the 9whp i gained, i lost 1.5wtq. but like i care, the gain was thru vtec and i opened it accordingly. our engines want to breath in and OUT there is nothing more efficient than a cutout short of header only or no exhaust at all. so having an optional exhaust (which i have with an electronic cutout), i get my no-hastle stock exhaust with the option to go "indy-car" in half a second.
the lean arguement is probably legit no matter how you view open header cause with a cutout mounted like mine, it exits before the sensors in the cat and turns on my cel light when open on cold days. -i dunno if k-pro allows for settings to account for one vs the other at the touch of a button. but the fact that i ran a much lower 1/4 mile time (.4) with my cutout open the entire time than opening it during WOT in 2nd leans towards the net power made with it untuned anyway. and modding your stock ecu'ed car at all will invariably alter your a/f ratio anyway, might as well go for the most power.


Cutout > twice as much $$$ and non-optional catback

 

if anyone can tell me where I can host a video for free, i will show you guys my cutout and atleast how it is mounted and sound level's vs stock.

 

putfile.com dude!!!! I wanna see

 

or youtube.com or streetfire.net or yousendit.com <---might be .net though

Either way, I'm interested in seeing this vid as well :driving:


lat-R