Electric Cutout Exhaust

[JayDM s13]

http://www.dmhperformance.com/ecutout.htm

what do you guys think about this? a bypass valve thats installed before the cat. so you can still have your stock exhaust with that aftermarket deep throaty sound...whats your guys opinion on this product...im thinking about getting this...do any of you guys out there have this on your 240???

[koukimonster139]

ugh so gay
get a real exhaust

[DrEaM MaKeR]

to be honest this is more for the domestic market, mainly for vehicles with bigger displacement for example LS1's

[gotta240]

dope. That beats a "real" exhaust in my book.

STOCK, QUITE sound when you are driving around. Open exhaust at press of a button. Old news, but still a great idea imo.

[johngriff]

This is worthless. You WILL lose power vs the stock exhaust, unless it is clogged, in which case something would be broken, and should be repaired.

Your Engine is designed and timed for an exhaust system over 10ft. The length of an exhaust system is incredibly important to the vacuum/scavenge effect, which increases horsepower and lowers exhaust temps.

That is it. There is no other way around it.

[JayDM s13]

ok cool...thanks guys...thanks for not clowning on me...and btw..i do have an after market exhaust...im just tired of the cops eyeballing me and smog is a hassle...

[Jeterkm02]

I havent had experience with them on my 240, or an NA car for that matter, but I have on my previous car.

I had a stock LS (1.8l non-vtec) powered Civic with a homemade turbo kit. It was a fairly small turbo running 9-10psi. I dyno'd with a 2.5" cutout closed at 178whp and 206whp with the cutout open.

Im well aware of the scavenging effects tuned exhausts are designed to have, but the magnitude of the gains from a e-cutout are really dependent on the motor setup and how restrictive the previous exhaust is relative to the cutout.

As for DMHPerformance, my cutout endured 2 new england winters and a handful of "bottoming out" experiences. The only problem i had with it is that the electric motor is capable of torquing itself and breaking its own mounts. If you avoid from holding the switch too long to open it when its already open then you wont have that problem, otherwise you can rely on the warranty. (a warranty dmhperformance honored with no questions asked.)

-Kris

[JayDM s13]

Originally Posted by Jeterkm02

I havent had experience with them on my 240, or an NA car for that matter, but I have on my previous car.

I had a stock LS (1.8l non-vtec) powered Civic with a homemade turbo kit. It was a fairly small turbo running 9-10psi. I dyno'd with a 2.5" cutout closed at 178whp and 206whp with the cutout open.

Im well aware of the scavenging effects tuned exhausts are designed to have, but the magnitude of the gains from a e-cutout are really dependent on the motor setup and how restrictive the previous exhaust is relative to the cutout.

As for DMHPerformance, my cutout endured 2 new england winters and a handful of "bottoming out" experiences. The only problem i had with it is that the electric motor is capable of torquing itself and breaking its own mounts. If you avoid from holding the switch too long to open it when its already open then you wont have that problem, otherwise you can rely on the warranty. (a warranty dmhperformance honored with no questions asked.)

-Kris

so it really did good for you on your civic? thats cool...

[fliprayzin240sx]

Originally Posted by JayDM s13

ok cool...thanks guys...thanks for not clowning on me...and btw..i do have an after market exhaust...im just tired of the cops eyeballing me and smog is a hassle...

If you already got an exhaust then get the Apexi Exhaust Valve thing, it works, i know people around me who got them.

[Silverbullet]

Originally Posted by johngriff

This is worthless. You WILL lose power vs the stock exhaust, unless it is clogged, in which case something would be broken, and should be repaired.

Your Engine is designed and timed for an exhaust system over 10ft.

His engine was also designed for 205HP but that dosn't mean anything. air flow has more to do with its volume than its actual length. Length is only one dimention in volume. Diameter can be substituted for length as far as flow and pressure goes. Obviously it'll change other variables such in the thermal dynamics and frequency department, but they dont really matter enough.

Loose power, really? Ever ran an open down pipe? Significantly higher top end vs having a oem catback. Same idea, except you can control exactly how much is opened. I see what your saying. The outlet is an over kill... kind of like having a 5" exhaust or something ridiculous. But again, you can control how much the valve opens. It all depends how much air there is going toflow. That means, its only most efficient at one point in the RPM range no matter what... for instance the stock 2.25" ID exhaust provides better low end power, where as if you switch to a 3", you imediately notice you loose that low end but you gain significant top end. As far as our cars are concerned, i would be pretty safe to say that we all would like an increase in the top end.

I had a Q-tec e-cut out and it worked great if you live in an area where exhaust is a big no no. I was getting pulled over about once a week (always Fri-Sat night) with my Apex N1 like 3 years ago until i switched to a cut out with an OEM cat back. Havn't been pulled over since for exhaust.

A friend of mine has a cut out in his 240 also. He has a funny story of him driving down some back roads real fast with the cut out open and passing a cop going in the opposite direction. He noticed the cop turned around to pull him over and he switched the cut out. The cop tries to argue that his stock S14 exhaust is aftermarket but dosnt give him a ticket. He was obviously in confusion after he forced him to rev up lol.


Anyways. I switched back to a ricer can only because my S13 is a drift car and tracks require a muffler. I have my cut out and my down pipe sitting in my garage. If your intersted in buying it, LMK. i'll give ua good deal.

[Nismoknightska-t]

Originally Posted by johngriff

This is worthless. You WILL lose power vs the stock exhaust, unless it is clogged, in which case something would be broken, and should be repaired.

Your Engine is designed and timed for an exhaust system over 10ft. The length of an exhaust system is incredibly important to the vacuum/scavenge effect, which increases horsepower and lowers exhaust temps.

That is it. There is no other way around it.

you are a idiot.. like most people on ziliva..
I run the same setup on my built ka-t but the QTP one.
Just make sure you put it has close to the muffle as you can.

On the dyno at 5.6 psi I did 205rwhp with the cutout closed and 241rwhp with it open.. With a gutted cat...

Cops dont even look twice at me..

[jspec240]

Originally Posted by Nismoknightska-t

you are a idiot.. like most people on ziliva..
I run the same setup on my built ka-t but the QTP one.
Just make sure you put it has close to the muffle as you can.

On the dyno at 5.6 psi I did 205rwhp with the cutout closed and 241rwhp with it open.. With a gutted cat...

Cops dont even look twice at me..

Haha I agree. I got one for sale 100$ shipped 2.5" and this is the perfect option for California drivers, as said before cops wont harass you unless you keep it open the whole time like some first time drivers...

[gotta240]

The scavenging effect is a good point, but is only valid to a certain point. When there is a completely open space for exhaust to travel, i believe it beats the scavenging effect.

If you wanted to get really anal about it, you could attatch a strait pipe to the cutout, helping the "scavenging" effect.

I also have trouble believing the engine was "designed" for a 10ft exhaust, and timing is any different. I'm not saying its not true, i just can't see how anything would change with different length exhausts as far as timing is concerned.. Again...not claiming to know this as fact...i simply can't see how it would be true though... School me.

[koukimonster139]

Originally Posted by gotta240

If you wanted to get really anal about it

dude you know i do

[MURPHY]

http://www.tuninglinx.com/html/apexi...ncer-test.html

be happy

[johngriff]

At the end of the day, I can only offer my opinion based off of knowledge and experience.

This is a great starting point, if you are still trying to figure things out, its only $20 which is less than a cutout or an exhaust system.

http://www.amazon.com/Scientific-Exh...2226134&sr=8-1

[MELLO*SOS]

Originally Posted by johngriff

At the end of the day, I can only offer my opinion based off of knowledge and experience.

This is a great starting point, if you are still trying to figure things out, its only $20 which is less than a cutout or an exhaust system.

http://www.amazon.com/Scientific-Exh...2226134&sr=8-1

I have that book, it's horribly outdated. I think it was last updated in the 60s and it focuses almost entirely on carbueration. I guess it's a good place to start... Just wanted to throw that out there since I was a little disappointed after I got it.

This book is a little more modern and covers some more advanced topics inc intake and exhaust dynamics:



If you must run some kind of throttle plate in the exhaust, I think the Apexi deal is the WTG.

[trsilvias13]

If you have a turbo car ATP has one that activated by boost.

http://www.atpturbo.com/Merchant2/me...egory_Code=BCS

[johngriff]

You've got to be kidding me..... I'll post tomorrow..

[Silverbullet]

on a typical SR setup: 198 peak WHP closed. 238 peak WHP open... mind you dynos are not accurate. They are precises but not accurate.. plus atm conditions are a huge variable.

[SILVIA_KIDs14.5]

Originally Posted by JayDM s13

http://www.dmhperformance.com/ecutout.htm

what do you guys think about this? a bypass valve thats installed before the cat. so you can still have your stock exhaust with that aftermarket deep throaty sound...whats your guys opinion on this product...im thinking about getting this...do any of you guys out there have this on your 240???

go wit someone trusted

apexi-usa.com

[Zetto*]

A friend of mine was running one of those on his g35 for a while. The sound and power was nice but he eventually went with a custom true dual exhaust.

[johngriff]

I like that book as a starting point, because it cover the absolute basics. Sections pertaining to wavelength and design are among the best practical explanations I have found. There are better more updated books, with the info presented in more of a practical manner, but they work off a foundation of known truths that I don't think all people may be in touch with.

240whp. Well GTFO out of here. Man that is so much power. and from 205 to 240! I wonder where the restriction was?


Oh right there, the horrid multisize crush bend.

Originally Posted by JohnGriff

This is worthless. You WILL lose power vs the stock exhaust, unless it is clogged, in which case something would be broken, and should be repaired.

You also have the cutout after the axle. You are retaining the legnth of the piping which is a necessary component to scavenge.

Now to get down into the mud. Honda Crews since 2003? With 240hp. You've got to be kidding me. I have met a couple of you guys, and you were all really nice, which is why you strike me as something else....

Is this you? http://www.youtube.com/watch?v=pB76eJDp3Js

Getting stomped on by a honda on manville? Ricky Racer street racing bs doesnt go very far. I was doing that in the 90's while you were still in middle school.

Get a full 3 inch cat back, it will serve you allot better.

Why length is important. While the volume argument might make sense, and evacuating exhaust sooner might seem like a gain, it is not. Enough cannot be said for a properly tuned pipe. Exhaust travels through a pipe in a wave length fashion. In that wave there are high frequency points, and low frequency points. These are pockets of high pressure and low pressure.

These pockets of low pressure act as a vacuum to the high pressure wave, accelerating their exit from the exhaust. If the pipe you use is too short, the exhaust will not build enough velocity on exit to maintain this effect. Too long and it will loose energy and create a dead zone or back pressure. There is a balance to this effect as well, when dealing with the CFM of exhaust output vs the diameter of piping.

From the drawing board, engines are optimized using cam/valve timing for a specific length of exhaust. The easiest way to work around modifying the length of the pipe is to adjust the cam timing. The added benefit of utilizing a full length exhaust in a turbo application is transient response of the turbine and rate to full speed of the turbine. The vacuum/scavenge effect will keep the turbine at a higher rate because the exhaust flow in the pipe is literally pulling the exhaust past the exhaust wheel.

In a naturally aspirated application, the length is playing the same role, but fullfilling what could be a much more necessary need, exhaust/intake stroke overlap. The point at which the intake and exhaust valve are open is overlap. At this point in the cycle the temp/pressure of the used fuel/exhaust gas pull out of the chamber, while fresh intake/fuel air mix is sucked in. The scavenge effect greatly increases this effect by pulling the exhaust out of the chamber, and at times sucking through intake/fuel mix. Besides completly cleaning the chamber of excess exhaust, the cool intake/fuel mix enters the exhaust port in the overlap, cooling the exhaust valve, header and system. This leads to a lower likely hood of detonation in an N/A application because of a red hot exhaust valve.

Hopefully I broke it down for you hommie.

[steve shadows]

Originally Posted by johngriff

From the drawing board, engines are optimized using cam/valve timing for a specific length of exhaust.

with a specific camshaft, head design, compression ratio and tune, yes.

But...with an EMS, high lift cams, and dyno time, you can tune for any length and style system your heart desire (maybe some machine work too).


I used a cut-out for drag apps back in the day. I had it half way down the exaust. It definitely had a negative effect on torqueand low end power but the higher ranges of the motor where exaust gas and movement of air was faster there was less effect and one a dyno more power.

There are plenty of people using t-cut outs on their cars for street racing or drag cars but if your doing a response oriented setup with anything other than a built head and ems, stick to a full length exaust with a muffler to meet your sound needs. It will be mroe beneficial for spool time scavenging etc.

[johngriff]

Right, but they are talking about, "throwin some cuttouts on dis bish"

[Nismoknightska-t]

Originally Posted by johngriff

Oh right there, the horrid multisize crush bend.

The crush bend is factory, that’s why I put the cutout right before it.. You said the cutout is worthless in your first post that’s the only reason I posted.. The cutout is the best thing you can buy period..

Originally Posted by johngriff

Now to get down into the mud. Honda Crews since 2003? With 240hp. You've got to be kidding me. I have met a couple of you guys, and you were all really nice, which is why you strike me as something else....

Like I said that was only at 5.6psi… wtf do you think I do at 20psi+??

Originally Posted by johngriff

Is this you? http://www.youtube.com/watch?v=pB76eJDp3Js

Yes, that is me.. that Honda has 503whp, if you look at the other video that is linked from that video you can see clearly that I spinning/getting sideways instill top off 3rd.. so wtf is your point? If you want to do it from a line PM me simple..

[nka203]

not to threadjack or nethin, but has anyone seen a 240 with a quad exhaust? thatd be hot.

[jilo]

youve got to be kidding me....

[jilo]

"not to threadjack or nethin, but has anyone seen a 240 with a quad exhaust? thatd be hot."

Originally Posted by jilo

youve got to be kidding me....

yea i deserve neg rep for that one... lol quad exhausts are the new hotness.

[jilo]

dbl post msglength