track-tested cutout yet again
Thread Starter
Joined: Nov 2001
Posts: 4,399
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From: Lubbock, Texas
track-tested cutout yet again Some of you may remember my post in early December about not seeing any gain from opening my cutout vs. running through my SLP dual/dual. Well, I said that I would try it out again the next time I went to the track, and I did. I saw NO difference with the cutout open vs. closed. I did run .05 slower w/ the cutout open, but my 60' time was a little over .02 slower on that pass. That's where the ET loss came from. I don't have a MAFT, so I wasn't able to richen the car up slightly w/ the cutout open. Some have said that they've seen a gain by adding fuel w/ the cutout open. The MPH was identical on both passes. I'm not opening the cutout again until I tear into the engine. <img src="gr_stretch.gif" border="0">
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Thread Starter
Joined: Nov 2001
Posts: 4,399
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From: Lubbock, Texas
Re: track-tested cutout yet again I have the O2 info w/ the cutout open, but I couldn't get it with the cutout closed. My laptop battery was nearly dead. <img src="gr_sad.gif" border="0"> I'll try it yet again in two weeks, and I'll post up the ATap data w/ each run.
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Re: track-tested cutout yet again I think that improvements with the cutout open vs closed are dependent on how free flowing your exhaust is after the cutout. I am running MAC headers, off road pipe, and a cutout into the stock muffler. I went from a 12.316 @ 109.71 with it open to a 12.459 @ 108.06 with it closed. My car seems to run just a tad bit leaner with the cutout open.
Link to O2 data.
ftp://members.aol.com/jnorris404/O2data.htm
John
98 Z28 12.20 @ 109.51, 1.707 60
Bolt ons
[ January 21, 2002: Message edited by: JNorris ]</p>
Link to O2 data.
ftp://members.aol.com/jnorris404/O2data.htm
John
98 Z28 12.20 @ 109.51, 1.707 60
Bolt ons
[ January 21, 2002: Message edited by: JNorris ]</p>
Thread Starter
Joined: Nov 2001
Posts: 4,399
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From: Lubbock, Texas
Re: track-tested cutout yet again John - You're exactly right! My intent was to see just how well the SLP dual/dual flows, and it seems to flow very well. If you're running into a stock f-body muffler, then you'll see a gain w/ a cutout on a bone-stock car.
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Re: track-tested cutout yet again I wouldn't exactly look at ET to observe for improments from a mod. ET is simply traction. MPH shows power gains/losses. You said your MPH was identical, which will then hold true that the cutout did nothing for you.
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From: Corona CA
Re: track-tested cutout yet again I dyno'd with cutout open/closed on a Stock 2000 SS running an Airlid and a 2.5" Y-pipe on factory cats. It has the SLP Dual-Dual from the factory. The Cutout is a 3" "Zed-Style".
Gained 3rwhp 3rwtq from 2500-6500. Not much, but it cost $25.
Probably wouldn't show at the dragstrip unless 3 passes of each were done and averaged. IMO.
Gained 3rwhp 3rwtq from 2500-6500. Not much, but it cost $25.
Probably wouldn't show at the dragstrip unless 3 passes of each were done and averaged. IMO.
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From: Kemah, TX
Re: track-tested cutout yet again Here is my spin on the cutout as of late. If you have a stock Z28 or TA exhaust a cutout will give a good gain. Someone dynoed about 17 more hp the other day at MTI with a cutout over stock TA exhaust. Nineball used to get 10 more hp over the TA exhaust with a Flowmaster muffler. However with a good freeflowing 3" catback the gains from the cutout will be minimal with a basically stock engine.
My $.02
Les
My $.02
Les
On The Tree
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Re: track-tested cutout yet again [quote]Originally posted by LS1JAY:
<strong>The SLP dual/dual seems to flow really well, my only complaint is that it's too quiet! <img src="gr_grin.gif" border="0"> </strong><hr></blockquote>
I would have to agree with you. I got an offroad y-pipe with my slp dual dual and hardly noticed any difference at all. so my solution was a simple 3" flowtech cutout. <img src="graemlins/gr_hail.gif" border="0" alt="[hail]" /> the sound is awesome with the cutout off!! there is nothing like ripping down the street and waking up the neighbors <img src="gr_eek2.gif" border="0"> <img src="graemlins/camaro.gif" border="0" alt="[Chevrolet]" />
<strong>The SLP dual/dual seems to flow really well, my only complaint is that it's too quiet! <img src="gr_grin.gif" border="0"> </strong><hr></blockquote>
I would have to agree with you. I got an offroad y-pipe with my slp dual dual and hardly noticed any difference at all. so my solution was a simple 3" flowtech cutout. <img src="graemlins/gr_hail.gif" border="0" alt="[hail]" /> the sound is awesome with the cutout off!! there is nothing like ripping down the street and waking up the neighbors <img src="gr_eek2.gif" border="0"> <img src="graemlins/camaro.gif" border="0" alt="[Chevrolet]" />
Thread Starter
Joined: Nov 2001
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From: Lubbock, Texas
Re: track-tested cutout yet again I LOVE the sound of the SLP dual/dual w/ my FLP's and ORP. It's nice and quiet, but it flows well. That's exactly what I'm wanting. It makes for a killer sleeper effect. <img src="gr_grin.gif" border="0"> Most people think I'm stock w/ a set of aftermarket rims, and that can make it fun on the street every once in a while. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" /> I had a 3.5" Mufflex w/ the dual-outlet Spintech muffler prior to the SLP, and it was LOUD. It was way too loud for my tastes, and that's how I ended up w/ the SLP. It's the best swap I've made yet.
As for looking at ET or MPH, I look at both and take the pertinent info into consideration (i.e. 60', etc.). Like I said, the ET difference was from the slower 60' time, but you're right that a HP-adding mod will show it's face in the MPH. It was worth nothing in both cases. <img src="gr_stretch.gif" border="0">
As for looking at ET or MPH, I look at both and take the pertinent info into consideration (i.e. 60', etc.). Like I said, the ET difference was from the slower 60' time, but you're right that a HP-adding mod will show it's face in the MPH. It was worth nothing in both cases. <img src="gr_stretch.gif" border="0">
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From: Helendale, Ca (SilverLakes)
Re: track-tested cutout yet again Back when I had a stock exhaust system; opening the Cutout showed Zero gain at the track.
I like my upgraded exhaust so much that I did not install a Cutout on it. <img src="images/icons/confused.gif" border="0">
[ January 22, 2002: Message edited by: highgear ]</p>
I like my upgraded exhaust so much that I did not install a Cutout on it. <img src="images/icons/confused.gif" border="0">
[ January 22, 2002: Message edited by: highgear ]</p>
Staging Lane
Joined: Nov 2001
Posts: 59
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From: Houston, Texas
Re: track-tested cutout yet again I think a lot of it has to do with what you have before the cutout also. For example, before I got my headers I only gained .5 MPH (1/8th mile) opening my cutout vs. running it through my Flowmaster. Now after my headers I gained 1.5 MPH (1/8th mile) opening my cutout vs. running it through my Flowmaster.
Re: track-tested cutout yet again My car ran consistantly picked up .05ET/.07MPH with the Cutout open.
This was a car running 11.50's w/Macs,ORY w/stock 2.75in exhaust to a Dynomax 17227 Ultra Flow.I had the cutout right before the over the axle pipe and thats where it seems to work the best.
I also picked up 6RWHP/8RWTQ on the Dyno threw the cutout.For me $30 was WELL SPENT!!!
JS
This was a car running 11.50's w/Macs,ORY w/stock 2.75in exhaust to a Dynomax 17227 Ultra Flow.I had the cutout right before the over the axle pipe and thats where it seems to work the best.
I also picked up 6RWHP/8RWTQ on the Dyno threw the cutout.For me $30 was WELL SPENT!!!
JS