Just installed some low profile exhaust cutouts from DMH. I researched all of the ones available and went with DMH. The quality is EXCELLENT and and Dave at DMH was excellent to deal with. These are very high quality pieces and would recommend them to anyone!

Enjoy!

Don

 

Don,

Beautiful installation! Very nice weld job. Did the flange and connecting section come with the dumps?

I’ve thought of installing a set of these too. Have you seen any performance difference with them?

 

DMH sends you : 2 motors,two flanges,two tips, a complete wiring harness and a switch. All you have to do is cut the pipes ,weld the flanges in and wire it. Be careful where you run the wire around the exhaust. Mine was welded off the car since I had the drive train out at the time. Since I had the tunnel apart I ran the wire up high in the tunnel and popped it up in the shifter area and put a switch in the ash tray.

Just put some thought as to where you put the valves and use mine as a guide. Notice that I have offset the valves so that they don't blow on each other.Also don't let them hang lower than the exhaust pipes for the most ground clearance.

I have a new 416 in my car and have not had it final tuned yet so I have not pushed it yet, but it very loud on the highway!

 

You whole system looks cool. Very clean installation!!Just curious ,,how much did they set you back for the kit??

 

How are you guys dealing with inspections? I believe they wont pass in PA.

 

I think the kit was about $350.00. They are the only ones with the low profile kit like mine. All others are round and not really for a Vette.

We do not have any type of inspections in Florida so nobody is looking!

Don

 

I don’t know much about states that require inspections, but if the valve are closed why wouldn’t it pass inspection?? Are you not allowed to have dumps at a racetrack if you frequent one in a state that has inspections?

I am curious on performance difference with the valves open to close. Is there a way to toggle the cal if different tune is needed?

 

Awesome!!! These are the ones I hope to get this summer.

 

The cutouts can be open in any position so they do not have to be completely open if you do not want them too.

Don

 

I can tell you on my car - see sig - I picked up ~17rwhp and 16rwtq. No tune is necessary. My WOT AFR was the same open or closed. Keep in mind this was done on a dyno with the cutouts open only for the runs. I have done some driving around with them open, but you have to be careful for noise concerns. I have never had a code pop from using them. BTW, they are one of the most fun mods I've done to my car.

 

I still have to install mine.

 

Don O,

Did you make the welds for your dumps? If yes, what filler rod did you use?

Thanks!

 

Absolutely gorgeous. Beautiful welding. Did you do this yourself?

 

That's about what I picked up when I had my 383. I agree that the cutouts allow for some immediate gratification at stop lights, parking lots, etc. Nothing like seeing the look on the face of your typical douche bag when he hears an LSx roar to life with a healthy cam through the dumps.

 

Wow you guys are picking up that much on stroker motors. I may have to get a set now that I am throwing in a 383.

 

John, I like your comment. I have been there too! I cannot take credit for the welds. I am not that good! I had a local SS fabricator do it.

I only picked up about two HP on the dyno. I have 1 7/8" American Racing headers,3" high flow cats and midpipes and a full 3" APS catback . Apparently it flows VERY good!

It is a fairly quite system compared to my old setup so that is why I put them on in the first place.

Don

 

How much leakage is there with these when they're closed? Is the car still louder with closed cutouts, than without cutouts at all?

 

These are high quality units no leakage when closed so no extra noise when closed!

 

Agreed. In the instructions, DMH states you must drive the car with the cutouts closed, getting them nice and hot. Then allow the car to cool completely. This apparently helps seat the cutout valves so you don't have leakage later. I did this and don't seem to have any leak problems. I picked about about 10-rwhp over the ZO6 ti-exhaust I'm running.

I second everyone else's comments, those welds are absolutely stunning!

I had the pipes off my car when the cutouts were welded on. Once welded, I went back into the pipes with a grinder and file to remove as much metal as possible on the inside of the cutout flange (making the hole as big as possible).

Regarding whether these will pass inspection: It depends on your state. Mine just failed because I had these cutouts (of course they were closed). Apparently NC law does not allow cutouts of any kind on a car.
Kind of stupid if you ask me. Yes I can open the cutouts after the inspection, but I could also later tear my catalytic converters out too. They should inspect the car 'as-is' and not what it 'could-be'. Besides, I'm neither decreasing the level of safety of my car nor increasing emissions...so what's the problem!
I'm going to spraypaint the bottom of my cutouts black so they'll blend in with the underside of my car...hoping the next inspection station won't see them with their little mirror thing.

Of course the same inspection place also failed me because I had a breather for my PCV system on my valve cover. I tried to explain that it shouldn't matter if the PCV system sucks air in from the intake box or from my breather, but they didn't care and failed me because it wasn't OEM.

This is a really great mod and the low-profile is the only way to go on a low sports car.