Exhaust cutout make a difference on Cammed LT1??
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TECH Fanatic
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Joined: Oct 2007
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From: Little Rock, Ar
Exhaust cutout make a difference on Cammed LT1?? Just bought a exhaust cutout recently, and its going on my car reguardless of if it makes a HP difference or not, but will I notice a difference at all? If so, will it be bottom end or all hwy where I notice it.. I tried to look up Dyno differences with open and closed cutouts but couldnt find exactly what I was looking for..
thanks
Kris
thanks
Kris
i noticed a better feel in power without one. It felt like i loss some bottom end torque with it open. I personally didnt like the cutout thats i why i eventually ditched it for a catback. The noise, drone, feel of losing some power all were drawbacks that eventually just got on my nerves.
I have no #'s to prove anything. Seat of the pants feel was more important then some dyno numbers
I have no #'s to prove anything. Seat of the pants feel was more important then some dyno numbers
Mine lost a little torque down low but gained a substantial ammount of HP up top. My DMH cut out on the dyno put down 16rwh more with it opened on my AI 200cc heads and cam package. With a cam only I would think you should pick up anywhere from 5-10 ponies. A buddy of mine picked up 5rwh on his 94 M6 with just bolt-on's. In the end you will love it...if it's electric that is. 
i noticed a better feel in power without one. It felt like i loss some bottom end torque with it open. I personally didnt like the cutout thats i why i eventually ditched it for a catback. The noise, drone, feel of losing some power all were drawbacks that eventually just got on my nerves.
I have no #'s to prove anything. Seat of the pants feel was more important then some dyno numbers
I have no #'s to prove anything. Seat of the pants feel was more important then some dyno numbers
With duals right behind the collectors my old LE2 package would pull hard up top. I just have a single in the I pipe now due to clearance issues.
It should be noted that you lose only a VERY SMALL amount of low end torque - hardly enough to notice. It's more of a psychological experience, louder exhaust feels slower.
Yes, you will gain power and torque with cutouts.
And all of those chiming in with that overused wornout wives tale of "losing torque because of reduced backpressure", go run the tests (intelligently....WITH DATA) for yourselves before regurgitating that crap.
All other factors being equal, reduced backpressure will ALWAYS result in more horsepower and torque.
The increased noise really plays tricks with people's "butt-o-meters" and brains, making them think that they're into the throttle more than they really are just because all that extra noise tells them it just has to be so!
There are other factors like collector length behind the headers that can enhance or reduce output, but again, all other things being equal, the less backpressure the better.
Even with a stock cam, depending on the flow quality of the catback, it's common to see 10 hp, reduced 60' times (that means more lowend torque for you nonbelievers
), and ET/mph improvement of 0.1 sec / 1 mph.
And all of those chiming in with that overused wornout wives tale of "losing torque because of reduced backpressure", go run the tests (intelligently....WITH DATA) for yourselves before regurgitating that crap.
All other factors being equal, reduced backpressure will ALWAYS result in more horsepower and torque.
The increased noise really plays tricks with people's "butt-o-meters" and brains, making them think that they're into the throttle more than they really are just because all that extra noise tells them it just has to be so!
There are other factors like collector length behind the headers that can enhance or reduce output, but again, all other things being equal, the less backpressure the better.
Even with a stock cam, depending on the flow quality of the catback, it's common to see 10 hp, reduced 60' times (that means more lowend torque for you nonbelievers
), and ET/mph improvement of 0.1 sec / 1 mph. Trending Topics
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We normally see 5-10 rwhp. but there have been larger gains with catbacks that do not seem to flow well.
I gained nothing with mine on the dyno, but I do have a 4" catbacj & I kept it since it does sound wicked open
I gained nothing with mine on the dyno, but I do have a 4" catbacj & I kept it since it does sound wicked open
Teching In
Joined: Dec 2009
Posts: 13
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From: Rochester, NY/ Hometown: Daly City, CA
LT1's love cut-outs! More so than LS1's that's for sure. You will notice a slight decrease in low-end grunt but will see a decent gain on the top end. The best $50-$150 mod you can do to an LT1 IMHO.
On The Tree
Joined: Mar 2007
Posts: 198
Likes: 0
From: Tacoma, WA
I unbolted the cutout on my cammed lt1 today for the first time since I installed the cam and it made a noticible difference. I nticed more of a difference unbolting it with the cam than without.
BTW, I'm about to buy an electric valve for my cutout. Does anyone know if summit's electric valve is any good?
BTW, I'm about to buy an electric valve for my cutout. Does anyone know if summit's electric valve is any good?