LT's to mid-length's
03-16-2005, 02:54 PM
#1
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LT's to mid-length's Right now I am running Long Tubes with no cats. How much hp would I loose if I switched to mid-lengths and cats. Since I live in Cali and smog is a bitch, this seems like a good way to go. But I would like to know how much I will loose hp wise IF I decide to do this. Thanks
03-16-2005, 02:57 PM
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Originally Posted by 777
hmm...i'd say 15-25hp...the most loss will be because of the cats...you may only lose 5-10 from the headers
03-16-2005, 03:01 PM
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Originally Posted by MeentSS02
Even mids would be illegal by the books, so I certainly wouldn't do that if it were me. Not too sure what you would lose power wise...probably not much as long as you used some nice flowing cats.
That brings up something else. I have my stock manifolds so I will probably do the swap from LT's to stock (only for smog) in my driveway. But my LT's are welded to my y-pipe and my y-pipe is welded to my exhaust. What am I supposed to do?
03-16-2005, 03:07 PM
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Originally Posted by 777
bring out a hacksaw or get an exhaust shop to cut it up and get some band clamps...that hp loss was just a guess...but i'd expect 5-10hp loss through cats...and i don't know really about the mids prolly 10-15...
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03-16-2005, 03:22 PM
#11
With the small cam you're running, you will lose 0-3 rwhp going to mid-length headers and 0-5 rwhp adding cats. Depending on the cats you chose, it is possible to maintain most of the hp numbers you already have. Just chose your exhaust wisely. Bassanis are a good mid-length header/cat combo. Mac headers are great, but the cats in their kit are no better than stock. If you used metal substrate cats instead, the Macs would be kick-***.
Don't believe it when the newbies tell you that you'll lose big hp going to mid-length headers. It's simply not true. Macs and Bassanis don't lose much peak hp at all compared to Kooks, QTPs and Hookers. Only in the mid-range, will you notice some difference.
Don't believe it when the newbies tell you that you'll lose big hp going to mid-length headers. It's simply not true. Macs and Bassanis don't lose much peak hp at all compared to Kooks, QTPs and Hookers. Only in the mid-range, will you notice some difference.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
03-16-2005, 06:47 PM
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Originally Posted by Patrick G
With the small cam you're running, you will lose 0-3 rwhp going to mid-length headers and 0-5 rwhp adding cats. Depending on the cats you chose, it is possible to maintain most of the hp numbers you already have. Just chose your exhaust wisely. Bassanis are a good mid-length header/cat combo. Mac headers are great, but the cats in their kit are no better than stock. If you used metal substrate cats instead, the Macs would be kick-***.
Don't believe it when the newbies tell you that you'll lose big hp going to mid-length headers. It's simply not true. Macs and Bassanis don't lose much peak hp at all compared to Kooks, QTPs and Hookers. Only in the mid-range, will you notice some difference.
Don't believe it when the newbies tell you that you'll lose big hp going to mid-length headers. It's simply not true. Macs and Bassanis don't lose much peak hp at all compared to Kooks, QTPs and Hookers. Only in the mid-range, will you notice some difference.
03-16-2005, 07:02 PM
#13
patrick is correct 
. check the exhaust guide for the macs vs LT's on a h/c setup, HP difference is minimal, the LT's have a better midrange but not substantial. porting macs and cutting off the ball flanges and there just as good as LT's. throw on some carsound high flow cats and i'd say you'd break even where your at now.
. check the exhaust guide for the macs vs LT's on a h/c setup, HP difference is minimal, the LT's have a better midrange but not substantial. porting macs and cutting off the ball flanges and there just as good as LT's. throw on some carsound high flow cats and i'd say you'd break even where your at now.
03-16-2005, 08:54 PM
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Originally Posted by jrp
patrick is correct . check the exhaust guide for the macs vs LT's on a h/c setup, HP difference is minimal, the LT's have a better midrange but not substantial. porting macs and cutting off the ball flanges and there just as good as LT's. throw on some carsound high flow cats and i'd say you'd break even where your at now.
. check the exhaust guide for the macs vs LT's on a h/c setup, HP difference is minimal, the LT's have a better midrange but not substantial. porting macs and cutting off the ball flanges and there just as good as LT's. throw on some carsound high flow cats and i'd say you'd break even where your at now.
03-17-2005, 11:23 AM
#15
Originally Posted by QuickBowtie
Hey thanks! I took a look at the exhaust guide. Do you really think I would break even with the mid-lengths and high-flow cats!? I am running no cats now. . .ah hell, I will look into the situation a little closer and give it some more thought.
loosing a few HP and gaining the chance to pass smog easier is a trade off i'd make anyday
03-17-2005, 01:53 PM
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Originally Posted by jrp
for the most part yes; porting the primaries and cutting off the ball flanges for a true 3" collector and some highflow cats (i like carsound myself) and the loss will be minimal on your setup.
loosing a few HP and gaining the chance to pass smog easier is a trade off i'd make anyday
loosing a few HP and gaining the chance to pass smog easier is a trade off i'd make anyday
03-17-2005, 03:12 PM
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Not sure about doing it in reverse, but with a 224/224 cam I picked up 2 mph in the 1/4 going from mids to LT's. Weather was worse after the LT install also.
