LT-1 tips
Thread Starter
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
LT-1 tips
Today I cut off the tips from a set of OE LT-1 muffler for my planned cat-back project. I have to say I was quite surprised to see that they are only 2" I.D. I thought they were 2 1/4, but I was wrong - definitely 2".
No wonder the LTx cars respond so well to exhaust changes!
I still have the mufflers and may cut them open as well just to see what they look like inside. Looking in from the ends doesn't look good.....
No wonder the LTx cars respond so well to exhaust changes!
I still have the mufflers and may cut them open as well just to see what they look like inside. Looking in from the ends doesn't look good.....
Thread Starter
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
That 2.5" system still goes through a big resonator and restrictive mufflers. Pipe size alone doesn't determine how well a system flows.
Burning Brakes
Joined: Mar 2005
Posts: 800
Likes: 2
I'm on mobile so I can't see your sig. If it is so restrictive why is it a popular upgrade for the pre-ltx cars to upgrade? The mufflers aren't that restrictive just too quiet. The res also isn't that restrictive, unless you are running a lot more power than stock, and it sounds like you have a fairly stout engine.
Drifting
Joined: May 2006
Posts: 1,428
Likes: 7
From: Chewelah Wa
I read a mag article where they put a 1300.00 Stainless exhaust system on a stock LT Vette, long tubes and everything. A gain of 6 HP was the result. I would post it, but it has been a few years. I would say the stock one was pretty good. I suppose there could have been a tune issue, but still.
Last edited by powerpigz-51; May 19, 2013 at 05:45 PM.
Le Mans Master
Joined: Oct 2008
Posts: 9,758
Likes: 49
From: Houston Texas
I read a mag article where they put a 1300.00 Stainless exhaust system on a stock LT Vette, long tubes and everything. A gain of 6 HP was the result. I would post it, but it has been a few years. I would say the stock one was pretty good. I suppose there could have been a tune issue, but still.
Thread Starter
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
I realize I don't have the reverse flow cooling and optispark, but neither of those are power-producing items. The reverse flow cooling was supposed to be to allow for higher compression ratios but that being done with better chambers instead now.
Am I missing something?
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Le Mans Master
Joined: Oct 2008
Posts: 9,758
Likes: 49
From: Houston Texas
The cam is a duplicate of the LT-4 cam, the heads use the LT-4 exhaust ports and an improved Vortec port which is based on the LT-4 port. The only difference at that point (to me) is the intake manifold, half a point of compression, and the computer. Granted I have to go through a single cat, but if we're talking engines they're basically the same thing.
I realize I don't have the reverse flow cooling and optispark, but neither of those are power-producing items. The reverse flow cooling was supposed to be to allow for higher compression ratios but that being done with better chambers instead now.
Am I missing something?
I realize I don't have the reverse flow cooling and optispark, but neither of those are power-producing items. The reverse flow cooling was supposed to be to allow for higher compression ratios but that being done with better chambers instead now.
Am I missing something?
Thread Starter
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
crank
rods
cam
heads
rockers
intake
timing set
oil pump
Canton pan
that I'd no longer have an LT-4 - or does the block still make it an LT-4 after all the other parts have been changed out?
And of those parts, which made a power difference aside from the heads, cam and intake - and possibly the rockers?
Tell you what - if I ever hit the Powerball or anything like that just for everyone to finally have real answers I'll buy a few different cars, lots of parts and spend a bunch of time dyno'ing all the different combos so that the whole world will have dyno sheets to back up what does what.
Le Mans Master
Joined: Oct 2008
Posts: 9,758
Likes: 49
From: Houston Texas
OK, so what you're saying is: If I had a 96 LT-4 car and rebuilt the engine using aftermarket:
crank
rods
cam
heads
rockers
intake
timing set
oil pump
Canton pan
that I'd no longer have an LT-4 - or does the block still make it an LT-4 after all the other parts have been changed out?
And of those parts, which made a power difference aside from the heads, cam and intake - and possibly the rockers?
Tell you what - if I ever hit the Powerball or anything like that just for everyone to finally have real answers I'll buy a few different cars, lots of parts and spend a bunch of time dyno'ing all the different combos so that the whole world will have dyno sheets to back up what does what.
crank
rods
cam
heads
rockers
intake
timing set
oil pump
Canton pan
that I'd no longer have an LT-4 - or does the block still make it an LT-4 after all the other parts have been changed out?
And of those parts, which made a power difference aside from the heads, cam and intake - and possibly the rockers?
Tell you what - if I ever hit the Powerball or anything like that just for everyone to finally have real answers I'll buy a few different cars, lots of parts and spend a bunch of time dyno'ing all the different combos so that the whole world will have dyno sheets to back up what does what.
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
The cam is a duplicate of the LT-4 cam, the heads use the LT-4 exhaust ports and an improved Vortec port which is based on the LT-4 port. The only difference at that point (to me) is the intake manifold, half a point of compression, and the computer. Granted I have to go through a single cat, but if we're talking engines they're basically the same thing.
I realize I don't have the reverse flow cooling and optispark, but neither of those are power-producing items. The reverse flow cooling was supposed to be to allow for higher compression ratios but that being done with better chambers instead now.
Am I missing something?
I realize I don't have the reverse flow cooling and optispark, but neither of those are power-producing items. The reverse flow cooling was supposed to be to allow for higher compression ratios but that being done with better chambers instead now.
Am I missing something?
MIke
Team Owner
Joined: Aug 2005
Posts: 34,988
Likes: 515
From: Riverside County Southern California
Co-winner 2020 C4 of the Year - Modified
2018 Corvette of Year Finalist
2017 C4 of Year
2016 C7 of Year Finalist
St. Jude Donor '09 thru '20
OK, so what you're saying is: If I had a 96 LT-4 car and rebuilt the engine using aftermarket:
crank
rods
cam
heads
rockers
intake
timing set
oil pump
Canton pan
that I'd no longer have an LT-4 - or does the block still make it an LT-4 after all the other parts have been changed out?
And of those parts, which made a power difference aside from the heads, cam and intake - and possibly the rockers?
Tell you what - if I ever hit the Powerball or anything like that just for everyone to finally have real answers I'll buy a few different cars, lots of parts and spend a bunch of time dyno'ing all the different combos so that the whole world will have dyno sheets to back up what does what.
crank
rods
cam
heads
rockers
intake
timing set
oil pump
Canton pan
that I'd no longer have an LT-4 - or does the block still make it an LT-4 after all the other parts have been changed out?
And of those parts, which made a power difference aside from the heads, cam and intake - and possibly the rockers?
Tell you what - if I ever hit the Powerball or anything like that just for everyone to finally have real answers I'll buy a few different cars, lots of parts and spend a bunch of time dyno'ing all the different combos so that the whole world will have dyno sheets to back up what does what.
You have a modified "L-98" engine.
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
OK, so what you're saying is: If I had a 96 LT-4 car and rebuilt the engine using aftermarket:
crank
rods
cam
heads
rockers
intake
timing set
oil pump
Canton pan
that I'd no longer have an LT-4 - or does the block still make it an LT-4 after all the other parts have been changed out?
And of those parts, which made a power difference aside from the heads, cam and intake - and possibly the rockers?
Tell you what - if I ever hit the Powerball or anything like that just for everyone to finally have real answers I'll buy a few different cars, lots of parts and spend a bunch of time dyno'ing all the different combos so that the whole world will have dyno sheets to back up what does what.
crank
rods
cam
heads
rockers
intake
timing set
oil pump
Canton pan
that I'd no longer have an LT-4 - or does the block still make it an LT-4 after all the other parts have been changed out?
And of those parts, which made a power difference aside from the heads, cam and intake - and possibly the rockers?
Tell you what - if I ever hit the Powerball or anything like that just for everyone to finally have real answers I'll buy a few different cars, lots of parts and spend a bunch of time dyno'ing all the different combos so that the whole world will have dyno sheets to back up what does what.
MIke
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
Today I cut off the tips from a set of OE LT-1 muffler for my planned cat-back project. I have to say I was quite surprised to see that they are only 2" I.D. I thought they were 2 1/4, but I was wrong - definitely 2".
No wonder the LTx cars respond so well to exhaust changes!
I still have the mufflers and may cut them open as well just to see what they look like inside. Looking in from the ends doesn't look good.....
No wonder the LTx cars respond so well to exhaust changes!
I still have the mufflers and may cut them open as well just to see what they look like inside. Looking in from the ends doesn't look good.....
As for whether people call it an LT1/4 or L98, if it has a similar cam, similar ports, similar intake, and similar exhaust, shouldn't the power be similar too? Actually, I like that an L98 can be upgraded with parts similar to an LT1/4. It seems like a good reliable way to go.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,062
From: altered state
St. Jude Donor '05
They may be good for the 300 rating. If hes truly making 80 more with his 350 bet he could pick it up some; not a bunch btu some meaning it wouldnt be a wash a 3" collector header would really help
Take the tips to a muffler guy see if it will fit in his expander. Have a set here and wondered the same thing or do some cutting/welding and make them work.
I wont call your 350 any names I dont think it cares.
Take the tips to a muffler guy see if it will fit in his expander. Have a set here and wondered the same thing or do some cutting/welding and make them work.
I wont call your 350 any names I dont think it cares.
Last edited by cv67; May 21, 2013 at 02:46 PM.
Intermediate
Joined: Dec 2012
Posts: 37
Likes: 0
From: Greenwich Ct Naples Fl Ct & Fla.
LT TipsNot LT 4
Just my 2 cents My L T 4 has 3" exhaust. I cut the mufflers off and put muffler eliminators on. The pipes I got were 3" all the way back. If you read an artical in this site you can see where stock L T 4s were tested and the H P ran anywhere between 245 to 280 STOCK so this engine according to tune can be all over the block. But an LT4 IS an LT4. You may have a clone [close]
Thread Starter
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
They may be good for the 300 rating. If hes truly making 80 more with his 350 bet he could pick it up some; not a bunch btu some meaning it wouldnt be a wash a 3" collector header would really help
Take the tips to a muffler guy see if it will fit in his expander. Have a set here and wondered the same thing or do some cutting/welding and make them work.
I wont call your 350 any names I dont think it cares.
Take the tips to a muffler guy see if it will fit in his expander. Have a set here and wondered the same thing or do some cutting/welding and make them work.
I wont call your 350 any names I dont think it cares.
My plan at this point is to run 2.5" into them but instead of expanding them (which I think would just split the steel or the welds) I want to run the tube directly into the "upper" part of the taper above the 2" opening. I'll use the bottom of the 2" as the starting point, then open it up from there. It's kind of hard to describe, but when the time comes to start fabbing it up I'll post pics and that will make a lot more sense.