Carl Fausett

We found a very nice electric cutout product and brought them in for photographs and inspection, and we were all impressed with the quality.

Photos below.

Website page here: http://www.928m.com/parts/exhaustcutout.php

HERE IS WHAT I AM LOOKING FOR: I do not have a nice before-and-after dyno chart for this product, nor pictures of one installed. I am looking for a test mule - some regular (not supercharged) 928 with a willing owner.

If he (or she) is willing to install this and give me pictures of the finished installation, I'll pay for both Dyno's (before and after) and provide a discount on the product as well.

Here is some of the text from our product listing:
BTW: the back of the cutout will support a length of pipe so you could run the open pipe to the side of the car -

How its used is up to you...
it is intended for DE days and weekend racers... but I am sure it will find a home among "other" types of driving.

I hope this will interest someone, and I can get some Dyno charts to validate the product.

Carl Fausett

One more thing - it should be obvious, but...

"NOTE - SOME FABRICATION REQUIRED: Although this is a complete kit, please be advised that installation of the Y-Pipe into your exhaust sytem will require some fitting or welding into your existing exhaust by an experienced exhaust system mechanic."

BC

I'd love to do that on my new 78 build. It could go after the X-pipe closer to the rear of the car. Scare the crap out of your neighbors, and then shut it again.

But thats months away.

SharkSkin

I'm not in the market for this at the moment... but will you offer smaller diameter single valves in the future?

hacker-pschorr

I am interested in the valve only, not the Y since I already have a custom fab muffler with a manual valve. My 79 will not be out of storage for at least another month though. Let me know if this arrangement still works for you.

Here are some pictures of this muffler, built by Jim Page:
http://members.rennlist.com/pageauto/guess.htm

sweanders

I have looked at those things before and figured that the added turbulance might disturb the gasflow. It will be interesting to see the results.

Ian928

This was my reaction too, why do these valves need so long to open or close? (I am not sure if this is the case for the valve in question though?) My idea was to use vacuum from intake to close the valve. That way, the valve open quick when you step on the gas, and close quick when you let off to change gear or brake. Maybe one could use a exhaust brake valve from a diesel truck or similar, I believe that these valves are vacuum controlled?

goldknight

Carl, I added one of those very units to my Trans-Am with a built 427 smallblock in it. made 48hp for me over the Borlla system i had in place (no cats) It also moved my tourqe peak up in the rpm range by 400 rpms if i recall right. But man was it loud. I was only allowed 1 pull on the dyno with the valve open. it would rattle the window of the store so bad they thought they were going to break.

The 928 engine breathes better then that small block chev so i would guess to see a little bigger HP increase.

All this just for refference. Cant wait to see your results.

Carl Fausett

Thanks for your interest and comments.

Sweanders - yes - I want to know if the high end benefits at the loss of mid-range... or vise versa! I do not think that will be the case, but it is all conjecture until I get some pulls on it.

I suspect the biggest gains will be from the 16v single exhaust system, especially if installed in front of the early cat which is known to be pretty restrictive.

As to the auto-opening idea - and why they take 4 seconds to open or close: we are using a DC-motor with good gearing here to close it and create a positive seal. The motor must have enough torque to shut against exhaust gas pressure and not leak. I think speed of opening/closing was second in design priority to "close hard and seal well", and "allow to remain partially open in any position".

Designed for a racer who wants one less thing to do when he gets to the track... now he does not have to get under his car and unbolt his cutout flange. Or for the fella that wants a little better MPG on the interstate by cracking it open a tad. Speed of it opening is not really an issue there.

As to open/close automatically - myself, I do not lkike that.... last thing I need as I romp on it at the traffic light is for the damn thing to open on me as I drive by the local Constable.... no, no, I want control of when and where it opens. :-)

Larry928GTS

I'd guess another reason for the slow opening and closing rate is that it would be easier to adjust it for the exact sound that you want than if it was very quick to move. Ever drive a car that had really quick power windows and try to just open them a very small amount?

Jim bailey - 928 International

It is 9:30 at night Saturday at the Azar's BigBoy drive in 1964 and the hotrod boys are idling through with the dump tubes open Whumpa da whump da whumpa ...

Carl Fausett

Thanks Jimmy! I am embarrased to admit I remember those days...

Any of you at Sharktoberfest might remember a 928 in the lot that had an electric cutout on it - he was blipping his throttle open and closed so we could compare... reminded us what we all already know - that the 928 is one of the best sounding engines anywhere.