Looking to get some sounds out of my XJR. I enjoy the quietness at times but sometimes I'd like really like to hear the car especially when I get on it.
I'm going to get high flow cats and then install the cutouts behind them.
Any experience with cutouts? How reliable are they? How long do they last?
I'm thinking about going with these QTP
I'm surprised it's not a common upgrade on GRM.
It's not common because it's crazy expensive and not grm. Most of Us nut jobs here love hearing our exhaust 24/7.
Are any of the drive by wire throttle bodies able to take the heat of the exhaust being pumped through them? Could be a cheap way to get electric cut outs.
I always wondered about using junkyard dbw throttle bodies for this.
I don't find them to be expensive. I'm wondering if I can have it wired in the steering wheel phone controls.
They work well and last a long time, the huge up-front cost is the only downside - lots of factory sports cars have electric cutouts these days.
If your car has CANbus and a spare switch circuit of some kind, you can probably reprogram a steering wheel button to control the cutout.
sesto elemento wrote: I always wondered about using junkyard dbw throttle bodies for this.
They won't stand up to the heat.
We've had threads before on alternatives to electric cutouts, and there aren't any, yet. If someone could make a decent cable-actuated cutout, that could work, but all the models on the market rattle and leak.
Use mechanical?
yupididit wrote: I don't find them to be expensive. I'm wondering if I can have it wired in the steering wheel phone controls.
Screw that, just have them open whenever you hit WOT.
FYI the cheaper and mid range ones form summit leak. I have only had luck with the really expensive ones in the past but that was at least 6 years ago.
A long time ago there was a thread here about DIY exhaust cutouts. Someone linked to a thread from another forum in which someone made vacuum operated cutouts in a dual chambered muffler.
They repurposed vacuum solenoids from an old style air cleaner to operate them.
They had a switch inside the car to deactivate the system. When the system was active the engine vacuum kept the solenoid closed. With mild to hard acceleration the vacuum dropped off and the solenoid opened up, passing the exhaust through the second, basically glass pack chamber for glorious noises. The same setup could be used for a straight bypass too, I guess.
Sorry, I don't remember who who posted the link, it what forum it cam from. It was probably 6 or 7 years ago.
Phff, kids, cut-outs, phff. The small center pipes are from the wastegates, while the large exhaust on the right is straight out of the turbocharger, just above it. 
kb58 wrote: Phff, kids, cut-outs, phff. The small center pipes are from the wastegates, while the large exhaust on the right is straight out of the turbocharger, just above it.
So you're using vacuum operated cut outs. Got it! 
Wait. Isn't that were the cut out threads ended last time. Just use waste gates. Or is that where my brain cut out last time?
In reply to RossD:
There's one problem with your logic. Cut outs are pressure operated, not vacuum, but since the OP's Jag is supercharged, it will probably work.
A wastegate will work fine, just pick the spring where you want it to open. If you want it switchable, use a boost control valve in serious with the MAP line running to the wastegate.
It rattles a bit at idle, but apparently spring-loaded flappers in the muffler work reasonably well and aren't terribly expensive.
wearymicrobe wrote: FYI the cheaper and mid range ones form summit leak. I have only had luck with the really expensive ones in the past but that was at least 6 years ago.
What brands did you have luck with?
Diesel EGR valves.
Everyone is deleting EGR on their diesels, no one is putting EGR back on, so they should be cheap. They should hold up fine to heat. Most are a butterfly type. I bet someone here can hack one to work on a switch. Try asking a diesel tuning shop. I bet they have a big pile of them.
Stock exhaust is cats, a single large center muffler, two rear mufflers, finally two mufflers at the end. Thats two cats and 5 mufflers.
I'm going to get highflow cats (proven for about 11hp and a little sound increase) then after the cats is where I want to install the cutouts.
Another brand that seems pretty good. Any use them before?
Dont the later years corvette mufflers have this built in?
I think exhaust cutouts are illegal in Illinois.
I had a qtp it leaked and intermittenly worked after a few years.
A buddy bought some cheapies on ebay. He paid about half what i did, he got two i got one. His also lasted for a few years. Id do the cheapies and consider them a wear item. I loved mine.
I will say with a large ass cam in an sbc the open cutout got old and i quit opening it. Cant really do anything without drawing attention. Like mold acceleration draws lots of unwanted attention. My buddies had a cammed late model hemi, he also quit using his for tbe same reason.
I've been reading that you can set them to be closed, completely open, or anything in between.
Still cheaper than aftermarket or custom exhaust. All while keeping the car completely quiet as it came stock.
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