some good cutout information
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Joined: Nov 2001
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From: Lubbock, Texas
some good cutout information I thought I'd post this since a LOT of guys install cutouts on their cars. I went out to Texas Motorplex this morning to TRY to get some runs in. I managed to get two in with no traction before it started raining, but those two runs showed some interesting stuff for open vs. closed cutouts.
I had an SLP dual/dual 3" catback installed, along with a cutout, this past Thursday to replace the loud 3.5" Mufflex. It's a LOT quieter, but I wanted to make sure that it was flowing just as well. I made one pass with the cutout closed, and then I opened it up in the pits for the 2nd pass. The car had an identical crappy 60' time (1.80) on ET Streets, and it went .06 SLOWER with the cutout OPEN. My MPH was down ~.5 w/ the cutout open as well. I was pleased to see that the SLP catback flows well. It just goes to show that you don't have to be loud to be fast. Open exhaust actually hurt my performance! This, of course, will be different for those guys running the stock Z28/TA catback because it doesn't flow near as well. FWIW, my last dyno run netted 333 RWHP. I don't know at what point I'll start showing a loss through the catback, but I haven't hit that point yet. <img src="gr_stretch.gif" border="0">
[ December 15, 2001: Message edited by: Trevor D ]</p>
I had an SLP dual/dual 3" catback installed, along with a cutout, this past Thursday to replace the loud 3.5" Mufflex. It's a LOT quieter, but I wanted to make sure that it was flowing just as well. I made one pass with the cutout closed, and then I opened it up in the pits for the 2nd pass. The car had an identical crappy 60' time (1.80) on ET Streets, and it went .06 SLOWER with the cutout OPEN. My MPH was down ~.5 w/ the cutout open as well. I was pleased to see that the SLP catback flows well. It just goes to show that you don't have to be loud to be fast. Open exhaust actually hurt my performance! This, of course, will be different for those guys running the stock Z28/TA catback because it doesn't flow near as well. FWIW, my last dyno run netted 333 RWHP. I don't know at what point I'll start showing a loss through the catback, but I haven't hit that point yet. <img src="gr_stretch.gif" border="0">
[ December 15, 2001: Message edited by: Trevor D ]</p>
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From: Athens, GA
Re: some good cutout information My friend Craig dynoed 1 rwhp and 1 rwtq higher through his open cutout compared to flowing through his dual/dual catback on his bolt-on '99 TA. I will definitely be running this catback on my next car.
Chris G
Chris G
Re: some good cutout information It's strange you mentioned that Trevor cause yesterday i noticed that my car accelrates faster and pulls quicker running through my flowmaster rather than my cutout. Guess next time at the track i will compare my cutout to my flowmaster setup.
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Joined: Nov 2001
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From: Lubbock, Texas
Re: some good cutout information [quote]Originally posted by DevilBird:
<strong>Well...you can't exactly have accurate info with only two runs (one opened and the other closed), and "no traction" on both runs.</strong><hr></blockquote>
It doesn't matter if no traction means 2.0 60' times or 3.0 60' times. The only thing that matters is that they're the same. As I mentioned in the post above, both 60' times were identical 60' times. I was ATapping both runs, and they were identical on timing, etc. The runs were made ~15 minutes apart. If the only change between the two runs was the cutout closed vs. open, can you tell me what happened? <img src="images/icons/confused.gif" border="0">
I'll be sure to track-test it again when I make it to the track next month.
<strong>Well...you can't exactly have accurate info with only two runs (one opened and the other closed), and "no traction" on both runs.</strong><hr></blockquote>
It doesn't matter if no traction means 2.0 60' times or 3.0 60' times. The only thing that matters is that they're the same. As I mentioned in the post above, both 60' times were identical 60' times. I was ATapping both runs, and they were identical on timing, etc. The runs were made ~15 minutes apart. If the only change between the two runs was the cutout closed vs. open, can you tell me what happened? <img src="images/icons/confused.gif" border="0">
I'll be sure to track-test it again when I make it to the track next month.
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Re: some good cutout information I've seen that happen before. But I can tell you that 9 times out of 10, you will gain.
When I had the custom 3.5 on the car with a cutout, I consistently gained 1 tenth more EVERY time!! This was tested on about 25 different runs.
I switched to the duals, gave me another tenth (plus a little.) Try it a few more times before you give up on it. Weather plays alot into what kinda times you will run. It could have been changing while you were waiting to run again.
When I had the custom 3.5 on the car with a cutout, I consistently gained 1 tenth more EVERY time!! This was tested on about 25 different runs.
I switched to the duals, gave me another tenth (plus a little.) Try it a few more times before you give up on it. Weather plays alot into what kinda times you will run. It could have been changing while you were waiting to run again.
Speed freak
Joined: Dec 2001
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From: Tulsa, OK
Re: some good cutout information [quote]Originally posted by Trevor D:
<strong>
It doesn't matter if no traction means 2.0 60' times or 3.0 60' times. The only thing that matters is that they're the same. As I mentioned in the post above, both 60' times were identical 60' times. I was ATapping both runs, and they were identical on timing, etc. The runs were made ~15 minutes apart. If the only change between the two runs was the cutout closed vs. open, can you tell me what happened? <img src="images/icons/confused.gif" border="0">
I'll be sure to track-test it again when I make it to the track next month.</strong><hr></blockquote>
OK.....basically what I was just saying was....that was based on only two runs. You can't just base your results on only two runs. I'm not dawgin' your info and saying it was wrong. I'm just saying that you need to do some more runs to have a solid-based outcome. I'm curious to see what your result are next month though, cause I too have a cutout <img src="gr_stretch.gif" border="0">
Miah
[ December 15, 2001: Message edited by: DevilBird ]</p>
<strong>
It doesn't matter if no traction means 2.0 60' times or 3.0 60' times. The only thing that matters is that they're the same. As I mentioned in the post above, both 60' times were identical 60' times. I was ATapping both runs, and they were identical on timing, etc. The runs were made ~15 minutes apart. If the only change between the two runs was the cutout closed vs. open, can you tell me what happened? <img src="images/icons/confused.gif" border="0">
I'll be sure to track-test it again when I make it to the track next month.</strong><hr></blockquote>
OK.....basically what I was just saying was....that was based on only two runs. You can't just base your results on only two runs. I'm not dawgin' your info and saying it was wrong. I'm just saying that you need to do some more runs to have a solid-based outcome. I'm curious to see what your result are next month though, cause I too have a cutout <img src="gr_stretch.gif" border="0">
Miah
[ December 15, 2001: Message edited by: DevilBird ]</p>
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From: Los Angeles
Re: some good cutout information Here's my B&B catback vs open ypipe (which is pretty much like an open cutout) on the dyno, back to back.
http://jmx.car-audio.net/car/dynograph-12-29-00.jpg
As you can see, on my heads/cam car it was worth 15rwhp at some points. Just providing more datapoints in the discussion <img src="gr_stretch.gif" border="0">
http://jmx.car-audio.net/car/dynograph-12-29-00.jpg
As you can see, on my heads/cam car it was worth 15rwhp at some points. Just providing more datapoints in the discussion <img src="gr_stretch.gif" border="0">
Re: some good cutout information jmX
So what you are saying is for cars with 400+ to the wheels it would be better to go with A cut out. I have the Loudmouth and I was thinking about going with B&B cause I have loss bottom end power but I am going to put A cam in soon so its most likly not worth getting the B&B right? And A cut out is pretty much the same as the loudmouth? Are you running cats? Cause I have no cats and I dont want to put them back on but not sure what I should do to pick up more power?
So what you are saying is for cars with 400+ to the wheels it would be better to go with A cut out. I have the Loudmouth and I was thinking about going with B&B cause I have loss bottom end power but I am going to put A cam in soon so its most likly not worth getting the B&B right? And A cut out is pretty much the same as the loudmouth? Are you running cats? Cause I have no cats and I dont want to put them back on but not sure what I should do to pick up more power?
Thread Starter
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From: Lubbock, Texas
Re: some good cutout information I agree that I need to test it out again to verify my results. I'll definitely do that, but I don't expect there to be much of a difference. I was expecting the car to run the same with it open vs. closed. There's no doubt that you'll pick up power with a cutout when you've opened the engine and replaced parts with bigger and better stuff. Dual cutouts were worth 20 RWHP on my 383 T/A. My first goal is to get to a track that will at least let me launch with full tracion. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" /> These crappy 60' times are for the birds.
Blacksunshine - What converter were you running when you gained .1 with the cutout? I'm curious to see if it was looser than what I'm running now. My Vig 3200 consistently flashes ~3,800 RPM just for a reference point. Keeping you up higher in the powerband could definitely affect the results. I hope to have a PT4400 in the car next month, so it will be interesting to see the results then.
Blacksunshine - What converter were you running when you gained .1 with the cutout? I'm curious to see if it was looser than what I'm running now. My Vig 3200 consistently flashes ~3,800 RPM just for a reference point. Keeping you up higher in the powerband could definitely affect the results. I hope to have a PT4400 in the car next month, so it will be interesting to see the results then.
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From: Corona CA
Re: some good cutout information I have one "Zed-Style" cutout in front of my SLP Dual-Dual (disc removed).
4 pulls, two with cutout, two without.
Cutout Open: 332,332
Cutout Closed: 328,329
I call it 3hp. Cost? $25 installed. ~$10/hp. Bargain.
Yes, a dual-dual flows better than any other full muffler I've seen on a dyno.
BTW- My track testing showed 0.06sec/.5mph loss by capping.
4 pulls, two with cutout, two without.
Cutout Open: 332,332
Cutout Closed: 328,329
I call it 3hp. Cost? $25 installed. ~$10/hp. Bargain.
Yes, a dual-dual flows better than any other full muffler I've seen on a dyno.
BTW- My track testing showed 0.06sec/.5mph loss by capping.
Thread Starter
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From: Lubbock, Texas
Re: some good cutout information [quote]Originally posted by Terry Burger:
<strong>My dual cutouts are worth 35rwhp and 40rwtq over the stock catback on my 2001. Across the entire band!</strong><hr></blockquote>
I have no doubt on that! A stock catback on a heads/cam package is a MAJOR bottleneck.
<strong>My dual cutouts are worth 35rwhp and 40rwtq over the stock catback on my 2001. Across the entire band!</strong><hr></blockquote>
I have no doubt on that! A stock catback on a heads/cam package is a MAJOR bottleneck.
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From: Lubbock, Texas
Re: some good cutout information [quote]Originally posted by TApimp:
<strong>all i have is a cutout on my 99 t/a and with it closed i got
60 ft -- 2.444
1/8 --- 9.064
i ran that twice it was only an eight mile track
with it open i ran
60 ft---- 2.200
1/8------ 8.802
so it helped me alot</strong><hr></blockquote>
All of your gain was in your 60' time, not the cutout. You dropped .24 there alone, and you showed a net drop of .26 in the 1/8. You're not going to be able to have an accurate comparison until you get some kind of traction to the point that your 60' times are at least the same (or very close). You just hooked up a lot better on that run.
<strong>all i have is a cutout on my 99 t/a and with it closed i got
60 ft -- 2.444
1/8 --- 9.064
i ran that twice it was only an eight mile track
with it open i ran
60 ft---- 2.200
1/8------ 8.802
so it helped me alot</strong><hr></blockquote>
All of your gain was in your 60' time, not the cutout. You dropped .24 there alone, and you showed a net drop of .26 in the 1/8. You're not going to be able to have an accurate comparison until you get some kind of traction to the point that your 60' times are at least the same (or very close). You just hooked up a lot better on that run.
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Re: some good cutout information all i have is a cutout on my 99 t/a and with it closed i got
60 ft -- 2.444
1/8 --- 9.064
i ran that twice it was only an eight mile track
with it open i ran
60 ft---- 2.200
1/8------ 8.802
so it helped me alot
60 ft -- 2.444
1/8 --- 9.064
i ran that twice it was only an eight mile track
with it open i ran
60 ft---- 2.200
1/8------ 8.802
so it helped me alot
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From: Derby, KS
Re: some good cutout information [quote]Originally posted by DevilBird:
<strong>Well...you can't exactly have accurate info with only two runs (one opened and the other closed), and "no traction" on both runs.</strong><hr></blockquote>
I agree completely that is way too little info to draw any judgement and the track is not the method I would used for testing a mod under 10 hp. Go strap it to a dyno and then tell us you didn't gain <img src="gr_images/icons/wink.gif" border="0"> The cutout was worth 7 rwhp and 5 rwtq for me.
<strong>Well...you can't exactly have accurate info with only two runs (one opened and the other closed), and "no traction" on both runs.</strong><hr></blockquote>
I agree completely that is way too little info to draw any judgement and the track is not the method I would used for testing a mod under 10 hp. Go strap it to a dyno and then tell us you didn't gain <img src="gr_images/icons/wink.gif" border="0"> The cutout was worth 7 rwhp and 5 rwtq for me.
Thread Starter
Joined: Nov 2001
Posts: 4,399
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From: Lubbock, Texas
Re: some good cutout information [quote]Originally posted by Dave Carney:
<strong>Go strap it to a dyno and then tell us you didn't gain <img src="gr_images/icons/wink.gif" border="0"> </strong><hr></blockquote>
I plan on doing that as soon as the new converter gets swapped in.
<strong>Go strap it to a dyno and then tell us you didn't gain <img src="gr_images/icons/wink.gif" border="0"> </strong><hr></blockquote>
I plan on doing that as soon as the new converter gets swapped in.
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