Using cutouts...a question about tuning
Thread Starter
Pro
Joined: Jun 2004
Posts: 672
Likes: 2
From: Louisiana
Using cutouts...a question about tuning
Howdy folks,
So, when discussing the possibility of a blower install, a local shop suggested that I not use cut-outs like I originally planned. They said that to tune the car with the cutouts closed would cause the motor to run poorly with the cutouts open. To tune the car with the cutouts open would cause the motor to run lean with them closed. Makes sense.
So what if I decide NOT to go with a blower setup (since I'm still trying to decide what kind of mods I want to go with). What if I go with an airbox (eg. Halltech Stinger or Trap), long-tubes (eg. Kooks), hiflow-cats and an X-pipe, which then exits through my Z06 system. If I leave those items as my only power adders, will I encounter the same tuning problems if I introduce cutouts into the equation?
Thanks!
So, when discussing the possibility of a blower install, a local shop suggested that I not use cut-outs like I originally planned. They said that to tune the car with the cutouts closed would cause the motor to run poorly with the cutouts open. To tune the car with the cutouts open would cause the motor to run lean with them closed. Makes sense.
So what if I decide NOT to go with a blower setup (since I'm still trying to decide what kind of mods I want to go with). What if I go with an airbox (eg. Halltech Stinger or Trap), long-tubes (eg. Kooks), hiflow-cats and an X-pipe, which then exits through my Z06 system. If I leave those items as my only power adders, will I encounter the same tuning problems if I introduce cutouts into the equation?
Thanks!
Last edited by SmokeyTirez; Jul 17, 2004 at 11:34 AM.
Team Owner
Joined: Sep 2001
Posts: 23,283
Likes: 906
From: Lake Elsinore, CA
Originally Posted by SmokeyTirez
ttt <again> Can anyone help with this one? Thanks!
I notice no significant degradation in power with the cutouts open. Actually, it feels a bit stronger, but that may be the pure psychological effect of the roar out the cutouts. One thing about vette cutouts is that you pretty much have to run them near the back of the car due to lack of clearance near the collectors. I tried putting them just aft of them but it was not gonna' happen. I ended up placing them just before the over-axle pipes next to the tranny.
Realize also that your talking about combining cutouts with a blower and I doubt any tuner would recommend that on a street car. Tuning would probably be a nightmare due to the complication of the forced air the tuner has to contend with and the varying back pressure open/closed cutouts would create. It's hard enough tuning a blown motor with a conventional setup. You could end up with two tuning programs - one you'd load with the cutouts open and one you'd load with them closed.
IMO, the cutouts work well with a street NA car. My h/c/headers setup loves it and it sounds great.
Team Owner
Joined: Sep 2001
Posts: 23,283
Likes: 906
From: Lake Elsinore, CA
Originally Posted by billjax
Patches, your underside (of the car!) is beautiful! How the HELL do you keep it so clean?? 
j/k
It's rarely been driven in the rain and I usually wipe it down when I'm under there, which is fairly often. No one but me sees it so it's mainly just because I would know . . . Oh, and you guys now. 
Thread Starter
Pro
Joined: Jun 2004
Posts: 672
Likes: 2
From: Louisiana
Thanks for the info Patches.
Still curious as to how the a/f ratio is effected by open vs closed cutouts on a N/A motor. Obviously they would be heavily effected on a s/c motor, because of the tune that must go in to control the fuel map for that application. But for a N/A car, I wonder if the tuning skews it far enough to one side that it would matter if you had cutouts.
I guess the safest thing would be to not get the car tuned, and run the OEM program. But then you're not making the most power you could.
Bottom line is that I'd really love to run cutouts. I like the Z06 muffler system I've installed, but it's just not loud enough for me. My wife is happy with it, and I'm happy with it from a flow perspective. But I really like a loud, angry V8. And when she's not riding with me (which is most of the time), I feel like I've short-changed myself with the Z06 system. I guess it all comes down to what I end up doing with the car. I still haven't decided if I'm going to s/c or not. Gotta sell my other car first before I even know how much funds I have for this anyway.
Thanks again for the response Patches. Just curious, has your car been tuned while you had the cutouts on? If so, did the shop guys caution you about using the cutouts after the tune?
Cheers,
Still curious as to how the a/f ratio is effected by open vs closed cutouts on a N/A motor. Obviously they would be heavily effected on a s/c motor, because of the tune that must go in to control the fuel map for that application. But for a N/A car, I wonder if the tuning skews it far enough to one side that it would matter if you had cutouts.
I guess the safest thing would be to not get the car tuned, and run the OEM program. But then you're not making the most power you could.
Bottom line is that I'd really love to run cutouts. I like the Z06 muffler system I've installed, but it's just not loud enough for me. My wife is happy with it, and I'm happy with it from a flow perspective. But I really like a loud, angry V8. And when she's not riding with me (which is most of the time), I feel like I've short-changed myself with the Z06 system. I guess it all comes down to what I end up doing with the car. I still haven't decided if I'm going to s/c or not. Gotta sell my other car first before I even know how much funds I have for this anyway.
Thanks again for the response Patches. Just curious, has your car been tuned while you had the cutouts on? If so, did the shop guys caution you about using the cutouts after the tune?
Cheers,
Team Owner
Joined: Sep 2001
Posts: 23,283
Likes: 906
From: Lake Elsinore, CA
I doubt my A/F is affected at all connsidering where my cutouts are. I'm running hi-flow cats and all 4 O2 sensors so a little less back pressure is not going to affect the tune much. I have not had it tuned with the cutouts in but I don't think it's necessary as I don't run with them open most of the time anyway. I would tune for the condition the car is driven in most of the time.
I also have the Z06 Ti's which is why I added cutouts. Stealth for those situations that call for it and
when the mood strikes. They sound downright nasty. I have a couple of vids at the bottom of the install page I did for the cutouts if you want to hear. One is opening and closing while idling and the other is a driveby with them open.
Cutout install and videos
I also have the Z06 Ti's which is why I added cutouts. Stealth for those situations that call for it and
when the mood strikes. They sound downright nasty. I have a couple of vids at the bottom of the install page I did for the cutouts if you want to hear. One is opening and closing while idling and the other is a driveby with them open.Cutout install and videos
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Instructor
Joined: Jun 2003
Posts: 160
Likes: 0
From: McAllen Texas
I totally agree with Patches. I have my stock Z06 exhaust with electirc cutouts right before the axle/tranny as well and let me tell you, they absolutely make the car ROAR when they are open. I love the flexibility to run them open or close at the flip of a switch. I get goosebumps when I go WOT with them open. If you are thinking of this mod, DO IT! It is by far my favorite mod.
