So I have my dohc car running pretty smoothly, and the exhaust work is coming to an end. But I would like to add a bit more to it.
This is my setup, which is on the car now.

I purchased a set of 2.5 inch dual outlet Hedman Hot Tips Resonator tips. I am finishing those up this weekend, and I will be sure to get pictures.

If you can't tell, I am running a 2 1/4 inch exhaust pipe, all mandrel bent, to keep exhaust velocity up, I used a stock replacement F-body muffler, and a free flowing catalytic converter. With the tips, this exhaust should keep it quiet. I really want the exhaust note to be smooth, and quiet. But not all the time.

I just purchased a header reducer set from summitracing.com. I am going to use it to install an electric cut out in my exhaust, directly after the manifold, of after the catalytic converter.
Here is what I ordered, I didn't just order a cutout pipe because of space limitations, plus I know these are the correct three bolt flange for the cutout. I can also use the second flange to bolt to the other side to use as an extension.
http://store.summitracing.c...700+115&autoview=sku


I am going to weld these into my exhaust, then put on these:
http://quicktimeperformance.../QTEC/qtecphotos.php



I will do a quick paint drawing of what I have in mind:


If there is room, I would like to run a pipe to the side, to avoid excess heat in the trunk area.

I don't see much discussion about cut outs on the forum, even using search. What do you guys think? I would like to hear your opinions

My exhaust is going to look like yours and i want to do a cut out to but the only thing is the price of cutouts is a lot more than i thought it would be.

You can always use the manual cut outs. The are just a cap that use wing nuts. You can find them for like 30$. You can also shop around for cheaper electric ones. The cheapest I found were $120. I think that is reasonable, but the quality may be questionable.

I really like a set i saw on ebay that use a choke cable but thats the only set i see like that.

the cable operated ones leak very badly, and are only available in 2 inch. I think the electronic ones will be worth it.

When you going to drive that car over to my house? Your doing some crazy stuff to it. Just make it run!! I recieved all the dohc parts not I just need to put mine back together. Wanna work on it? I'll give ya a rear bumper! Take care Nick
Matt

I wouldnt. I had a cutout on mine, ran like crap with it open. I ended up just capping it off, because it would dog and run bad and sounded like crap with it open.

that will be loud and probably mess with your knock sensor which will retard timing

Matt, I will be in this weekend, and I will be sure to give you a call. I need to get a master cylinder, and I think my clutch line is clogged? Anyway, you should come see the car. It looks terrible on the outside, but it runs very well. I need to come up with an intake and fix my clutch stuff, then put on my calipers, and it will be moving under it's own power, but the body is terrible.

Anyway, I realize that I would probably lose a lot of low end, but I did not realize it could make the motor bog or mess with the knock sensor. What if I placed the cut out directly after the catalytic convertor? I think that may give me the louder sound I want, and still maintain just a little backpressure? I just want to be able to open it up and have it sound absolutely vicious, Cause right now, it's exhaust sounds like an almost stock car.

Nick

quote Originally posted by mrjohnishome: Matt, I will be in this weekend, and I will be sure to give you a call. I need to get a master cylinder, and I think my clutch line is clogged? Anyway, you should come see the car. It looks terrible on the outside, but it runs very well. I need to come up with an intake and fix my clutch stuff, then put on my calipers, and it will be moving under it's own power, but the body is terrible. Anyway, I realize that I would probably lose a lot of low end, but I did not realize it could make the motor bog or mess with the knock sensor. What if I placed the cut out directly after the catalytic convertor? I think that may give me the louder sound I want, and still maintain just a little backpressure? I just want to be able to open it up and have it sound absolutely vicious, Cause right now, it's exhaust sounds like an almost stock car. Nick

You could surround the knock sensor with shielding insulation..I did that to mine and it stopped the timing from being pulled. Try to put the cutout as far away from the knock sensor as possible

The DOHC is one loud ass engine when open exhaust

I have decided to place the cut out after the catalytic converter, then route the exit pipe to the side to avoid interference with the knock sensor.
Nick

quote Originally posted by 86GT3.4DOHC: I wouldnt. I had a cutout on mine, ran like crap with it open. I ended up just capping it off, because it would dog and run bad and sounded like crap with it open.

your doing something wrong then....

quote Originally posted by darkhorizon: your doing something wrong then....

It might have been the knock sensor. Bottom line, the engine sounds like crap with no exhaust, its fun at first, but it makes you sound like a damned ricer, though with some balls behind it.

You do have to get it pretty far away from the knock sensor, when I first built the car, I just used a stock DOHC downpipe, which dumped it out behind the car, it ran okay, though I didnt drive it much like that, it sounded really bad. With the cutout, it sounded like crap and ran like it too. My cutout basically shot the exhaust in the area of the passenger rear cradle bolt.

Im running a flowmaster 80 (or is it 40?) and its a little too loud. What muffler is that in your pic?

On top of that, engines are designed with backpressure in mind, but the cat should help, but running an engine completely open will cause issues.

I am using a Walker stock replacement muffler, I can look up the part number if you want, but I don't have it handy. I know that themotor is extremely loud with an open exhaust, and I ran it like that when I first started it. But I think if I place the cut out after the catalytic converter, I will get a decent sound. I had the same style cat and a glasspack "fart can" on it before I bought a real exhaust, and It sounded very smooth, but it was just loud. Plus, I truly believe that those fart can have no muffling capability whatsoever, nd may actually have made it louder. so I think I will put it after the cat and post the results on monday If it sounds bad with it open, I will just put a cap on it instead of buying the electric cut out.
Do you guys think that puttting that in my exhaust will change my exhaust sound when it is shut?

[This message has been edited by mrjohnishome (edited 11-06-2008).]

I got the cut out on, along with one of the tips. I did start the car once, with no cut out installed on the flange, and I thought it sounded pretty good. I sounds smooth, not too much pop in the exhaust, which I like. You were all right, it is pretty loud. It isn't unbearable. I would image that an exhaust with jsut a flowmaster etc. would be louder. It does sound pretty smooth, but is quite rumbly. It doesn't sound like a ricer at all. It sound vicious. I can't wait to install the electric valve. I am worried about leaks though. Here are the pictures:





I have to admit, with the cutout, it is quieter than the original exhaust:
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