Alright,
I went by my buddy's exhaust shop today who will be doing all the fab work for me and we came up with some plans.

On my stage 3 S4 I ran dual electronic DMH cutouts and they were amazing. Very loud, quick spool, great top end power. Then when I was tired of the noise, I just pushed the button to close them and everything went quiet again.

So i've done this before, i'm familiar with how we're going to do it.

This setup will be on a stock 996tt exhaust. We plan to cut into the bottom or lower sides of the catts, gut them, then weld the flange onto the whole where we cut them out and attach the two cutouts.

I sketched up some pictures of what i'm going for. This is not 100% accurate, but it'll give you guys an idea of what i'm going for. Again, I did an almost exact setup on my S4s, with the DMH cutouts and it worked wonderfully.

What do you guys think?

I won't be using the black V-tube they provide, we'll be making a T-tube so that it'll sit at a 90 degree angle (perpendicular to the catalytic converter).







These are them on a corvette:

 

The turbos get red hot and they are very close to your planned location - be careful of the wires and electronics melting.

 

Certainly,
When I had the setup on my S4 the wires ran up alongside the downpipes right near the turbos. They never failed me or ever melted; I had the setup for several months and it proved itself reliable.

I'll make sure to wire everything up away from the turbos.

DMH also guarantees their cutouts for 3 years I believe, so if anything were to happen i'd be able to replace them.

 

This was actually done before. The car lost power. I looked into this option way back when...really. I am the "J" in the "TMJ MOD" exhaust.

I think you could get more data from Imagine Auto as I think Steve Kaspar was the one who told me about it. The vendor of the gadget used his name on the product...and he told me he had not been aware of it working well....so I am not sure that the product still has his name on it....shall we say. He was not backing it.

I had planned to do the same thing. There is one commercial unit like it out of Europe. Very expensive...9ff and perhaps another company.

Anyway, fyi. Not a new idea. Sound may be cool...but you could lose power. It will weigh something...and the car is so low that the valves may not survive long.

For the price, get a good exhaust and be done with it. Cheap is under 2000. Expensive is about 5 k.

Your hole is going into the main cat of each side....it may be a big mess if even possible.

jb

 

The cats will be gutted so the mess will just be getting them cleaned out, but that's all. I know you stated the car 'lost' power but I did a lot of research today from guys running straight pipes (literally) - which is what this setup is... And they didn't lose power, even though a couple guys noted that they felt they lost power.

I've seen dyno's on other turbo cars where they gain up to 20whp with a totally free flow setup.

I don't see how the car will lose power, this topic has been beaten to death, the car loses torque down low, but greater flow/faster spool doesn't mean a loss in power? I could be wrong though.

Someone correct me if i'm wrong. And the valves will be fine, they sat lower down in my S4 than they will on this, a good 3-4" lower and I never had issues. The last thing i'm worried about is with something concerning the valves... I'm more curious as to what people think about the setup, that's all.

Any other comments?

 

There are commercial products doing this, so it can work. I think the problem with the pre-made valves was the space and the sharp angle that had to be negotiated.... It was dynoed by Stephen and lost power ....email him. I could be wrong. I ruled it out due to the KISS principle.....I don't want yet another thing that can break 2" above the road. ON track, it will break if it can break. With my luck, it would hit my driveway and gouge that on the way out first drive.

Neat idea. In theory, it should work.


JB

 

I may try it just to try it.

I just don't understand how he would of lost power on the dyno doing it? I mean isn't the idea of straight pipes to gain faster spool time, more power (as a result of more flow), and more noise?

I may try to see ifwe can adapt a Y type setup to it instead of a T setup. In that case i'd have the cutout mount at 30-45 degree angle on the insides of the cats - meaning they'd be higher from the ground and not on the bottom, less chance of them scraping?

We'll see

 

I came across this post by onelove from Titan Motorsports who was speaking of the straight-pipes they were running on their 996TT. These are straight out from the turbo, just like how my cutout system would work - I actually plan to do more of a Y style setup now instead of the T style like before - it should help the exhaust flow ou the cutout easier this way. So my question is, if this is a straight out setup, like my proposed Cutout-setup then why would they run something that would cause it to lose power? Just curious

Looks like it gives them good gains, so shouldn't the cutout setup too?

https://www.6speedonline.com/forums/2217229-post43.html

 

straight pipes lose aprox 50 lbs from the rear...

 

looks like a fun project... give it a try!!
tim

 

I know there is a weight advantage, and that's a nice setup, but not for daily driving. I'm looking for versatility.

I want it to be loud as **** and quick spool time when I open them up and want to run down the interstate, but quiet in the neighborhood.

I'd also expect to see some good gains from the setup simply due to the fact that the exhaust flow would be increased by a large amount.... Which we all know is a very good thing on turbo cars.

 

I've run cutouts on my Supra, I've gutted cats, and now have straight AWE pipes on my 996tt...Just so you know I have a little experience talking about this stuff.

-Turbo's may get hot but melting wires is not a concern, wrap them with anything for a little protection.

-Cutting the cat and welding the valve is silly. Too close to the turbo in regards to turbulence exhaust...You need a little pipe, make it the length of a stock cat min. Or make a y-pipe with a little pipe to let the exhaust out.

-You can gut the cat with a baseball bat and shoving it in the hole, and shaking the exhaust to empty it out. (I like to use the pole off of my old patio umbrella personally)

-You won't lose power on the cutout but will be loud.

-AWE pipes have crazy drone 2-3K and I will be removing them and up for sale in 1-2 weeks.

-Lite weight pipes mean a lot to me so I'm making a custom exhaust with an x-pipe to help with the sound and stay moderately lite.

These valves are old school tech, you want new school? Check this out....

http://www.youtube.com/watch?v=C556EHYUijA

[media]http://www.supraforums.com/forum/showthread.php?t=525346&highlight=cutout[/media]

 

Thanks for the tip man, I've seen those boost activated cutouts before, they're awesome. My buddy has one on his new big turbo jetta and I think his cutout was set to about 14psi before it would open.

The thing I like about that is it's consistent. So your tune stays consistent with the exhaust flow. With electric cutouts you can have them opened and closed at different times, so your ECU may not be set right to the current open or close position.

With those, your exhaust will always "open" up to flow completely free at xx psi so your ECU is on target each time you boost.

And yes,
I realized that welding the value at a right angle to the cat would be dumb, so i'm going to have a 3-4" pipe go off it at 45 degree angle - give or take, so that the flow is much much better than at a 90 degree angle.

 

Video?

 

Worst case scenario if it doesnt work out.... just buy good exhaust.