IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED)
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From: Katy, Tx
IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) I've been told by some that the cutout gains HP. I've been told I won't like it cause of the lost Torque and I've heard you lose HP on a fairly stock car!!!I would like everyones opinion on this PLEASE, I'm suppose to get one put on Tuesday, but if it cause me to lose performance I don't want to spend $$$ on it 
Staging Lane
Joined: Oct 2002
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From: Memphis, TN
Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) I'm running a crappy Flowmaster muffler on my car, only because it was on the car when I bought it.
At Hypertech, I laid down a 13 RWHP increase, plus an increase in TQ when I opened the cutout.
It also netted me a nice little gain on the track.
At Hypertech, I laid down a 13 RWHP increase, plus an increase in TQ when I opened the cutout.
It also netted me a nice little gain on the track.
Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) NEVER see anyone loose HP with a cutout. I've heard people say it "feels" like less torque.. but they are usually surprised to find out thier but-0-meter isn't calibrated 
Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED)
NEVER see anyone loose HP with a cutout. I've heard people say it "feels" like less torque.. but they are usually surprised to find out thier but-0-meter isn't calibrated
Launching!
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From: Wichita Falls, Texas
Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) I have longtubes and ORP and cutout. I would only gain 1-2 HP/TQ with the cutout open on the dyno. The guy running the dyno said that the curve looked like knock with the cutout open. Could the cutout give false knock that would pull some timing? You can see the lines deform a little on the dyno sheet that's not there with it closed.
Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) You were probably leaning out with the cutout open and it was pulling timing. Losing hp with the cutout is likely due to another problem.
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Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) You may loose driving around torque (idle-1500rpms) but you should make around 10hp. I have heard of cases of false knock or perhaps some other issue. A cutout general you should get 10-15hp with a stock catback.
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Verdad Gallardo Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) Also, if you like it loud Id recommend removing the stock catback altogether and save 50lbs. I never capped my cutout. It was a hair too loud though. I think it would have been perfect with a 3"bullet muffler after the ypipe. Something else to consider and it would cost the same.
Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) the stock ls1 is looking for a little backpressure to keep it in line...cutouts before the Y collector will hurt horsepower and torque a little...but after will gain a few...not much difference...only 3-5 hp max.... IF you got a ringer... but usually the "Free mods" and a few simple bolt-ons will make you much happier...try loudmouth exhaust...much better sounding and good for 20 hp. headers...good for 8-30 hp (dependent on brand and design(short/long/equal length) an air lid(mti-whisper-tsp) is usually good for 5-15 hp....and mti lids are only $99...bet you will spen more than that on cutouts...that you have to cover when there are cops around....and you wont get near as much performance out of them, oh...and you nned to buy a K&N filter...only $50...reuseable/cleanable....good for a few ponies...get the drift...cutouts are only for guys with a Lot of BIG POWER ADDERS, and for the track...cause cops wont like you and will ticket you for Noise(disturbing the peace in most areas)(usually $40-$150 state/county dependent)(ouch!!)cops dont mind the SLP Loudmouth...as long as you dont lay into it right in front of them or in a residential area...(if you do they give you a noise ticket and a Gross diaplay of horsepower ticket-my buddy found out the hard way...DumbA*s!!) :p
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From: Lockport,IL
Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED)
the stock ls1 is looking for a little backpressure to keep it in line...cutouts before the Y collector will hurt horsepower and torque a little...but after will gain a few...not much difference...only 3-5 hp max.... IF you got a ringer... but usually the "Free mods" and a few simple bolt-ons will make you much happier...try loudmouth exhaust...much better sounding and good for 20 hp. headers...good for 8-30 hp (dependent on brand and design(short/long/equal length) an air lid(mti-whisper-tsp) is usually good for 5-15 hp....and mti lids are only $99...bet you will spen more than that on cutouts...that you have to cover when there are cops around....and you wont get near as much performance out of them, oh...and you nned to buy a K&N filter...only $50...reuseable/cleanable....good for a few ponies...get the drift...cutouts are only for guys with a Lot of BIG POWER ADDERS, and for the track...cause cops wont like you and will ticket you for Noise(disturbing the peace in most areas)(usually $40-$150 state/county dependent)(ouch!!)cops dont mind the SLP Loudmouth...as long as you dont lay into it right in front of them or in a residential area...(if you do they give you a noise ticket and a Gross diaplay of horsepower ticket-my buddy found out the hard way...DumbA*s!!) :p
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Joined: Nov 2001
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From: Troy, AL
Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) "the stock ls1 is looking for a little backpressure to keep it in line...cutouts before the Y collector will hurt horsepower and torque a little...but after will gain a few...not much difference...only 3-5 hp max.... IF you got a ringer..."
We dynoed about 15 RWHP gain with my cuttout open on my internally stock '02. I have the stock Z28 muffler. The cuttout is 3". The headers are 1 3/4". Runs were made back to back.
We dynoed about 15 RWHP gain with my cuttout open on my internally stock '02. I have the stock Z28 muffler. The cuttout is 3". The headers are 1 3/4". Runs were made back to back.
Staging Lane
Joined: Oct 2002
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From: Memphis, TN
Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) http://www.wtfba.org/dyno/Roger_Cotton.jpg <-- Copy/Paste since our webmaster refuses to allow direct linking.
My dyno results. Both runs were done on the Dynojet at Hypertech, a few minutes apart with the coolant temp at 180* at the start of each pull. Both pulls were 4th gear pulls.
My dyno results. Both runs were done on the Dynojet at Hypertech, a few minutes apart with the coolant temp at 180* at the start of each pull. Both pulls were 4th gear pulls.
Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) Cutout loses power at 1500rpms and makes more and more power as the rpms increase. Look at the difference between in hp at 6250rpms. its 21rwhp. Peak hp difference is only 11hp. Its definitly a worthwhile mod. Hopefully this will clear up the back pressure controversy that I never believed in the first place.
Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) I have been looking into cut outs also. From a little research I found out that you will gain some hp and tq even on stock cars. The problem I am having is that I already have a good flowing exhaust (Mac headers w/orp and loudmouth) on a H/C/N20 500+rwhp car but not sure if I will gain anything by having 1 3" cutout in the I-pipe? This one company that sells cutouts said I would lose a little low end tq by
having 2 cut outs in the y-pipe. They said I might gain some hp tq with 1 cut out in I-pipe because the benefit you get is having the opposite side exhaust pulse help pull the one coming out the cylinder. Since the engine is really cross firing, you lose the benefit when you decouple the exhaust pipes and dump each one individually. Thus, you'll lose a bit of scavenging. I might just get it and see what happens.
having 2 cut outs in the y-pipe. They said I might gain some hp tq with 1 cut out in I-pipe because the benefit you get is having the opposite side exhaust pulse help pull the one coming out the cylinder. Since the engine is really cross firing, you lose the benefit when you decouple the exhaust pipes and dump each one individually. Thus, you'll lose a bit of scavenging. I might just get it and see what happens.
Re: IFFY on Cutout's Performance (OPINIONS WANTED & NEEDED) My IROC picked up about 25 HP w/ a single 3" cutout in place of a gutted cat. went from 12.39 @ 109.5 to 12.17 @ 111.93, JUST from the cutout.