Raceland exhaust cut-out

[CAH8]

I saw this thing on RacelandUSA.com and it reminded me a friends Dad's Panamera with the "changable" exhaust. Im not really sure what to call it. Has anybody ever had one or seen one or have any videos or pictures of it?

[Arachnotron]

Dual DHM cut-outs on a Corvette.



For videos search youtube for "DMH cut-out" or "QTP cut-out"

[AZGolf]

As long as they're installed post-catalyst, it should be "ok" and the heat should be manageable.

[20V_DUBBIN]

Even the "quality" cutouts like QTP are prone to failure. I wouldnt expect that raceland one to last long. my .02 cents. However i am a huge fan of cutouts because its cheaper than a full exhaust with greater power potential and more stealthy when you want to be quiet.

[Iroczgirl]

They have their purpose. As stated before though, one made by Raceland wouldn't last very long.

[Aonarch]

Lol a Raceland product on a Porsche... good luck.

They are called electronic cut-outs.

[CAH8]

Lol a Raceland product on a Porsche... good luck.

They are called electronic cut-outs.

The porsche didnt have the raceland cut out. It had astock electronic cut out

[CAH8]

Even the "quality" cutouts like QTP are prone to failure. I wouldnt expect that raceland one to last long. my .02 cents. However i am a huge fan of cutouts because its cheaper than a full exhaust with greater power potential and more stealthy when you want to be quiet.

What exactly do you mean by fail

[rs4-380]

The porsche didnt have the raceland cut out. It had astock electronic cut out

No, it is not a cutout. It's a muffler bypass. Same thing they have on MKiv r32's and plenty of other cars.

What exactly do you mean by fail

Between the heat, water spray and various other crap on the road they often seize up from corrosion and/or leak (which sounds like crap) or the motors fry.

[CAH8]

No, it is not a cutout. It's a muffler bypass. Same thing they have on MKiv r32's and plenty of other cars.



Between the heat, water spray and various other crap on the road they often seize up from corrosion and/or leak (which sounds like crap) or the motors fry.

Gotcha thanks for clearing that up

[20V_DUBBIN]

The condensation inside of the pipes wreaks havoc on those little flappers, then they get corroded and fry the motors.

[MightyDSM]

What is the purpose of these? Just sound?

[mellbergVWfan]

What is the purpose of these? Just sound?

More pah!

[Internal Combustion]

What is the purpose of these? Just sound?

Cutouts are the best of both worlds. On my old Jeep 5.9, a 3" cutout was worth 7 rwhp over a small case 3" magnaflow and mandrel bent pipe. Mine was a manual cutout. 2 seconds to great sound, power. 2 seconds underneath the car back to street legality. Electronic cutouts are that much better.

1. driving with stock exhaust (or aftermarket)
2. flip swtich
3. noise, pah
4. cop/neighborhood
5. back to stock


Cutouts on a LSx vehicle are worth 10-15 hp over aftermarket exhaust. You could run headers into stock exhaust and have a cutout here and probably pick up 25-30 rwhp.

[PineappleMonkey]

The SP Racing cutouts are absolutely the best ones on the market as there is no motor to fry. They use wastegates for their operation. Also available for NA motors.

http://www.spracingonline.com/store/...ry.php?sub=111

[emkaytree]

I could maybe see that working better vacuum or hydro powered.

[Klim18]

Gotta use em erre day to prevent any problemz.

[AuForm]

I don't see how this is so great for the flow and I don't approve of avoidable air pollution (given performance criteria) and to some extent sound pollution (though I am willing to allow exceptions).

Plus - you're doing the opposite of what aerodynamic engineers try to do with the airflow of the underside. If a slight angle of a flat undertray can generate hundreds of kilo equivalents of downforce - what happens when you dump all your exhaust under the car when you're flooring it in top gear? I'd be weary.



The Glickenhauzer uses the exhaust as an aerodynamic feature, as do other fully streamlined designs like the Gumpert Apollo. You can see the exhaust on top and there are also tracts going down and coming out in the diffuser to gradually suck air back into the hole that the car made minimizing turbulence and thus lift.

Which is sort of the opposite of dumping your exhaust where you actually want negative pressure.

[rs4-380]

Plus - you're doing the opposite of what aerodynamic engineers try to do with the airflow of the underside. If a slight angle of a flat undertray can generate hundreds of kilo equivalents of downforce - what happens when you dump all your exhaust under the car when you're flooring it in top gear? I'd be weary.

[IMG]ht

you are reading to much into it. there aren't many cars out there that actually have/utilize downforce aiding under trays and those that do spend little time at the speeds that make them effective. You'll see these the most of cars that have zero aerodynamic design considerations (muscle cars) .

[clutchrider]

My buddy back in highschool had something like this on his 80's Camaro. He would remove the ashtray underneath was the ground and the exhaust piping. He installed a flapper on a wire pull that basically routed the exhaust straight out to the side instead of through the cat and muffler

It was hilariously loud.

[FissionMailed]

Plus - you're doing the opposite of what aerodynamic engineers try to do with the airflow of the underside. If a slight angle of a flat undertray can generate hundreds of kilo equivalents of downforce - what happens when you dump all your exhaust under the car when you're flooring it in top gear? I'd be weary.

I'm sure VW/Jeep/Chevy spent millions on the aerodynamics of the 70s Golfs/Camaros/Wranglers people install these things on

[AuForm]

So what you're saying is ... aerodynamics don't effect cars that aren't aerodynamically efficient.

Which means putting aerodynamic features on un-aerodynamic cars won't effect the aerodynamics because the cars aren't aerodynamic.



I don't know if the effects will be disastrous but effects will be effected. And to me - it looks like a pretty dumb thing to do - dumping your exhaust under the car. Since everybody designing cars is trying to get air out of there.

[FissionMailed]

Oh sure, it'll affect the car. That said, there is a difference between putting a big wing on a car and throwing an exhaust cutout under a car.

P.S. the car you posted is actually a super-aerodynamic car that really did have zillions thrown into the aerodynamic design, thanks

[rs4-380]

So what you're saying is ... aerodynamics don't effect cars that aren't aerodynamically efficient.

Which means putting aerodynamic features on un-aerodynamic cars won't effect the aerodynamics because the cars aren't aerodynamic.



I don't know if the effects will be disastrous but effects will be effected. And to me - it looks like a pretty dumb thing to do - dumping your exhaust under the car. Since everybody designing cars is trying to get air out of there.

that car had zero underbody aerodynamics. They focused on frontal area and rear downforce. My point remains, for the impact that it makes on the cars that these end up on you are talking about drop in the bucket.

[IronJoe]

The SP Racing cutouts are absolutely the best ones on the market as there is no motor to fry. They use wastegates for their operation. Also available for NA motors.

http://www.spracingonline.com/store/...ry.php?sub=111

Holy crap I didn't know these existed. THANK YOU for posting this!!

[AuForm]

Oh sure, it'll affect the car. That said, there is a difference between putting a big wing on a car and throwing an exhaust cutout under a car.

P.S. the car you posted is actually a super-aerodynamic car that really did have zillions thrown into the aerodynamic design, thanks

It started out like this. Which means it is an aerodynamic feature on an originally un-aerodynamic design. And the actual surface of the wing is not that big, it's the location that is vital here. It's more a splitter than a down force wing - if you know what I mean.

While all modern cars have to take aerodynamics into account just to meet mileage standards. So all cars are aerodynamically engineered. The top side and the bottom side and the rest of the sides.

But that's not really the point.

My first point is, this is just a hole in your exhaust. It will mostly make a lot of noise - performance wise. It will improve your airflow like a hole in your intake will: not. It'll most likely create turbulence that will slow the air evacuation. Just like making extra holes in your flute won't make it sound better. It will in fact become a crappy flute.

Second, while one tries to create a low pressure area under the car - this does the exact opposite. It probably won't launch your car into the air, but the point remains, this is the opposite of what you want to improve the performance of your car.

So what are the benefits? Noise like you're driving around with a hole in your exhaust.
What are the drawbacks: f-ed up exhaust evacuation and f-ed up underbody aerodynamics. (which are used for instance to cool the brakes).

By incorporating the exhaust system into the rear diffuser, you can also help extract the air from the rear of the car more effectively .The exhaust gasses produced effectively energise the airflow, helping to raise the low pressure air .This fast moving air flow returning back to the ambient atmospheric pressure at the exit of the diffuser, reducing drag levels. Hot exhaust gases also aid in expansion, again aiding in the airflow speed transition between fast moving underbody air and slow moving ambient air. Resulting in higher vacuum effect, more downforce and reduced drag.

The diffuser is rather sensitive to engine speed, so if the driver lifts off the throttle, lose of downforce is experienced ( as a result to speed and exhaust gases). The exhaust flow is greatly reduced off throttle and makes the diffuser less effective, robbing the downforce generation effect. This can cause handling issue where the rear of the car might become twitchy and prone to more lift off oversteer , on throttle release. Engine mapping can overcome this by pumping more air out even when off throttle.

http://www.rapid-racer.com/aerodynamic-upgrades.php

[MikeSAABt]

If you think dumping exhaust under the car is going to appreciably affect the aerodynamics of 99% of road going cars you are completely dreaming.

No one's saying your understanding of aerodynamics is wrong but you've got to look at it a little more practically by application here. Also you kind of dismiss it as just for noise, but look a few posts up there's real world whp to be gained. I don't think the dude gaining 7whp is going to notice the new high pressure area under jeep

[FissionMailed]

Well...okay, so don't throw one on a car that has a diffuser and underbody that's designed for aerodynamics. On a Super Bird, though, you're probably okay.

(protip: people really only do this mod to make their car both really loud and also not a ticket magnet during the 99.9% of the time it's closed, they typically drive fox body 'stangs/Z28 camaros/firebirds)

[curvedinfinity]

If you think dumping exhaust under the car is going to appreciably affect the aerodynamics of 99% of road going cars you are completely dreaming.

No one's saying your understanding of aerodynamics is wrong but you've got to look at it a little more practically by application here. Also you kind of dismiss it as just for noise, but look a few posts up there's real world whp to be gained. I don't think the dude gaining 7whp is going to notice the new high pressure area under jeep

At highway speeds this kind of change could create noticeable lift. Something maybe in the 20 lbs to 60 lbs range. Especially since it is load dependent, it might be weird feeling at 80 mph. For any modern car which has an underbody aero strategy, messing that up is probably not a good idea. I like the idea though. It would be cool if the exits routed outside the car... Maybe to the sides or something.

[AuForm]

another victory

[MikkiJayne]

Audi have something similar on the B6 RS4: (OE on the right)

[VDub2625]

WHat does that do, open a bypass through the OE muffler, or just ad a second exit for more airflow?

And why do people feel the need to troll constantly? Does anyone get ANYTHING out of it? Besides your jollies?

[RacerrRex]

How did an exhaust cutout thread turn into a debate about aerodynamics

[Woodski]

How did an exhaust cutout thread turn into a debate about aerodynamics

because TCL

[MatchStick]

when I put cutouts on my Jeep I will take care to think about aerodynamics... lol...