Exhaust Cut-out [Merged 8-9] cut out bypass

[v8s_are_slow]

We've kinda been there, done that.

oops, kinda forgot about the whole search feature for a second there.

ATP Turbo has a new option as well that is operated by a WG. A little pricey but I dont see why you couldnt make your own. http://www.atpturbo.com/root/releases/release091004.htm

that'd be nice if ya don't mind it opening all the time. 15 psi would be pretty easy to hit all the time. especially at highway speeds. i'd prefer to open it when i want to. that's just me though.

 

[eyebrowski]

that'd be nice if ya don't mind it opening all the time. 15 psi would be pretty easy to hit all the time. especially at highway speeds. i'd prefer to open it when i want to. that's just me though.

Kind of a PIA but I don't see why you couldn't use an MBC with it.

 

[v8s_are_slow]

you know, it'd be cool to have a stang or something pull up next to ya at the light and wanna race, flip a switch and all of a sudden the car starts getting louder while just sitting over there and then just turn to the guy and give him a big hehe! especially with cams. haha! something else to add to my list of mods

 

[AL92]

I had a quick time cutout on my 99 trans am.It leaked when supposedly closed and after I sold it to another guy that new it leaked when closed it straight died on him.Stay away from them..bad design.
I then bought a dmh cutout..similar but supposed to not leak..more money than qtp.It leaked also when closed..annoyed heck out of me.I am sending it back its got like a three year warranty and will sell it off.I am going rear mount turbo on my 99 trans am and dont' need a cutout.The system don't even use a muffler and isn't that loud.

I am not sure how much power a cutout would be worth on a dsm.I did have a downpipe open briefly on my car and thought it sounded bad.These 4 cylinders just don't sound like a v8 ok..But my apexi n1 catback and down pipe with no cat sound great in my opinion and can throw the silencer in there if the cops start hassling me.

 

[Defiant]

Don't get caught with one on the street.

 

[eyebrowski]

If I got caught with half the shit on my car...

 

[Dallas J]

If I drove south to kalifornia I would probably be shot on sight.

No egr, charcoal can, cat... Well, its not a daily driver so Im not polluting the world that much

-Dallas J

 

[Mark S.]

Rear mounted turbo.... ::shudders::

 

[AznW/BigTurbo]

ATP Turbo has a new option as well that is operated by a WG. A little pricey but I dont see why you couldnt make your own. http://www.atpturbo.com/root/releases/release091004.htm

I was so surprised when I looked at the link above. Just over the last summer I came to develop the same concept/idea with a friend of mine by integrating a diaphragm actuator with a throttle body! I wonder who thought of it first? Regardless, having owned and daily driven a car with 3" cutout right off the downpipe, I know a lot about living with one. At first it sounds bada$$ and I got all kinds of looks driving around. Suprisingly I didn't get pulled over while cruising with it opened but I found the following to be annoying

1) Since the cutout was pre-cat, the car smelled really bad especially pulling into a garage
2) I felt that the boost response was a little improved yet it is noticeable that the turbo spooled much slower.
3) It is loud as hell and it takes time and effort to close the cutout. Imagine the eletric cut-out as a window switch: it takes quite a few seconds to completely close/open the valve. If you have a manual one, it is quite a hassle to jack up the car, bolt the cap on/off, and lower the car. By that time your competition is probably laughing his/her ass off.

The good thing with the diaphragm cutout is, the opening of the valve (atleast in my concept) operates gradually and in reference to the boost of the vehicle. In order to induce quicker spool, a turbocharged vehicle desires back pressure in the low rpm yet as it cranks through the higher rpms, the turbo needs room to breath and needs a free-er flowing exhaust system. The beauty of the diaphragm actuator cutout is it does exactly that. On low rpm when the driver desires boost and gets on the gas, the low boost pressure in addition to the lower velocity of exhaust gas will only partially open the cut-out--which induces higher back pressure. As the boost builds to full setting and with the exhaust gas accelerating, the valve (if tuned correctly) will open TPS 100% and allow the restrictive (perhaps OEM) exhaust system to all of a sudden free up room to breath-thus providing lesser back pressure for the benefit of the turbo up in the higher rpms. If tuned correctly also, at partial throttle cruise (no boost or in the Vac), the cutout will ideally be closed and the system will sound exactly stock--only until you open it up WOT and all of a sudden your car is a monster 4 banger or not.

All of this could be controlled by a "MBC" as referenced before and more intelligently by a EBC. Depending on the travel allowed by the wastegate arm and how the boost affects the movement of the arm, the boost controllers can essensially be tuned so that the valve will only open say when it hits 18psi. This type of design is heading toward a future wave of variable tunable systems. This will be further tackled by ProjectSoloGear in the coming months.

Gus/Dom

 

[v8s_are_slow]

if it sounded just like my external tial gate when it opens it really wouldn't be a big deal to me if it opened up everytime under boost. but if it was just way louder everytime.....more than it already is, i dunno if i'd want that. hmmm.....wish someone had a sound clip or something. i'd think that the further back that it's mounted, the better it'd sound, but at the same time, the closer towards the motor it's mounted, the better it'd perform for having less back pressure. also, i'd wonder how fast the thing would open up if it's opening under boost. like half a second??? it'd totally defeat the purpose if it's gonna take 5 to 10 seconds to open up. ya know?

 

[86MCSS]

About the ATP cutout...I have been talking to a couple buddies on Ls1tech that have this installed on there turbo Ls1 cars. They all say its fully open at 5psi. And they all agree its a great device because you lose no bottom end back pressure for the turbo and and right when you need the free flowing exhaust the ATP cutout opens [5psi]. They only problem they see with it, is that it may have limited installation positions because of the size of it. Lowered cars could have a hard time finding a nice place to install it.

 

[AznW/BigTurbo]

More about the Valves opening.

There are two key factors in affecting the valve opening. One would obviously be the exhaust gas force pushing on the throttle plate. The second would be the setting of the diaphargm actuator spring rating. When cruising (no boost or in VAC), factor number 1 will determine how much the throttle valve opens. When going under boost, the positive pressure that is hooked up to the top cavity of the wastegate actuator will aid in pushing against the springs embedded in the bottom cavity of the wategate, thus forcing the arm to move outward. Thus, both factor 1 and 2 will come into effect.

With that said, we've determined that one factor is at random and cannot be controlled (factor 1) and thus the tunability will be left to factor 2, the wastegate control. Now, how can we control this effectively? Well, easy! Assuming those who are reading this thread owns a turbocharged DSM/vehicle, we all know how an internal wastegate actuator works on the turbo. Those who experiment with MBC and EBC knows that such devices can delay the opening of the wastegate flapper in the O2 housing (in other words delay the wastegate arm from moving out). Thus, we can theoretically setup the system to open whenever we want, be it 5psi or 20psi.

Now the idea I've been playing around involves not a CNC machined throttle plate but instead I've sketching the concept with an throttle body. The difference being the throttle body comes with an integrated spring coil. This spring coil acts as a force against the opening of the throttle valve, thus providing more resistance. If this resistance can be controlled so that the exhaust gas force doesn't push the valve open under undesired condition such as too early or leaking at low throttle cruise, we can control factor 1. But WAIT, we CAN! The fact that the throttle body comes with a spring coil will allow us to fine tune both factor 1 and 2, thus creating a much more tunable and intelligent design. Plus, a throttle body comes with TPS sensors telling you how much the throttle is opened. Now we're talking.

Gus

 

[1badtsi]

<< qtec owner here, when i first got mine it died, but they replaced it within a week so quicktime still is in my good graces

been working fine ever since, and i love seeing v8's when i open it and rev a little, you can hella hear the turbo wind down,

gives me tingles

 

[v8s_are_slow]

have any fitment issues when you installed it? whereabouts in the exhaust did ya install it? near the front? back??? any comparisons to the sound of this and an external dump wastegate?

do you have to just weld it in or are the ends expanded to slip over the ends of the pipe on the exhaust once it's cut? that'd make the install so much easier.

 

[1badtsi]

i bought a 2.5" straight pipe and welded the cutout into that, fits right in place of my cat, so when i need to , i can put the cat back on and pass smog

and the sound while cruising is just super bass-y , but when wot you can hear me from half a mile off :laugh:

 

[1fstSS]

i have a 3 inch flowtech cut out and a dmh electric opener latin around, were should i mount it??right after the down pipe?? or weres the optimal place??? thanks!! btw what kinda performance am i gonna see from this?? i know a cut out knocked a full tenth off my camaro what about these turbo cars??

 

[MyEclipse5]

i have a 3 inch flowtech cut out and a dmh electric opener latin around, were should i mount it??right after the down pipe?? or weres the optimal place??? thanks!! btw what kinda performance am i gonna see from this?? i know a cut out knocked a full tenth off my camaro what about these turbo cars??

I dont know about time, but freeing up your exhaust will add a big jump (from what i've heard).

I'd mount it where the cat is, unless you have emissions, then mount it on the DP. But thats just me.

 

[dre99gsx]

Thought some might be interested:

http://www.twingles.com/ideck/misc/qtec/qtecinline.htm

Any feedback would be appreciated.

To summarize: An electric cutout is being used INLINE with the exhaust. Close=quite cruising, Open=Loud, but muffled, WOT. So far so good.

 

[CvicKila02]

For some reason i don't think this would be the greatest idea. Alot of backpressure would be caused, that would go back to your turbo and possibly dammage it because the gases have no were to go (those two small holes don't seem like enough). I give this guy props for trying this, but i would see more of an advantage if he used a small exaust 2.5" so that it would be quite, and somewhere really close to the turbo on the downpipe install the cutout to vent near the tires somewhere. I think that it would be out of sighn of a nosey cop looking to give you a hard time. Also you wouldn't have to worry about building up backpressure. Feel free to correct me if i'm wrong in thinkin this.

 

[GSX_RCR]

Holy backpressure! 2 - 9/16" holes = roughly larger than 1" opening diameter.

1) He's going to burn up some valves and the seals in his turbo by the extreme backpressure.

2) That cutout will probably get cooked in a few weeks of use.

:thumbdown

 

[pneumo]

Thanks for the excellent writeup, Dre. I'm curious about the low end power for crowded freeway driving. For example, if I want to jump from the slow lane into the fast lane on a crowded freeway, is there still enough power? Does downshifting still give you more power?

 

[noz]

damn..that look hella restrictive...
i think he shoulda just use a pot type switch instead of drillin those two small hoes.

 

[DSMJim]

I think that is pretty innovative honestly. You will have easy daily drivability, good gas mileage and super quite exhaust. What we all really want when were not at WOT. Then flip the switch when you wanna go fast and away you go.

Just wait until the eBay losers get all over this.

 

[WhiteCloud]

It is a great idea IMO, although I believe the holes need to be an inch diameter each. A 2 inch exhaust will not be loud, but it won't create so much backpressure to kill a high flowing turbo either.

Oh, and I disagree that the cutout will become "cooked"...these are made specifically to endure high temp exhaust gases flowing over them. All electrical components are heat wrapped and coated, and I believe extra procautions are also taken with the valve itself to make it more durable. It should last 3-4 years minimum.

 

[dsm10sec]

I'd say make at LEAST 3 maybe 4 holes and put in a switch on the throttle cable so when you get above 60% it opens ON ITS OWN! Now that's something I'D buy for sure.