Road race/steet engine. Need 345 rwhp. 5.7 or 5.3?
#61
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What does the average set of 16 gauge, 304 stainless long tubes weigh, vs. the stock iron manifolds and down pipes??
Dropping weight off of the nose would be my only motivation for using LTs, but then having to de-tune the car/use a very weak cam to meet NASA power level requirements.
Dropping weight off of the nose would be my only motivation for using LTs, but then having to de-tune the car/use a very weak cam to meet NASA power level requirements.
#62
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[QUOTE] IMO a stock cam with LTs would be my choice over an aftermarket cam and stock manifolds.
Less weight, more torque, softer lobes, less engine heat (if you have them coated).
Shorties are a good way to drop weight (even over LTs) but not add much power in order to stay within a certain power limit.
No. I just figured they aren't necessary for my power goals. The ls1 I'm going to get comes with stock manifolds and I've read that they 01-02 manifolds actually flow pretty well. So I figured I'd save the money on LT's and put it towards a cam that will put me at the power I need, which is 350 rwhp or so. Plus I won't have any ground clearance issues.
Seems the cost is going to be about a wash. LT's with an LS6 cam or stock manifolds with a mild cam. Then I figured if I want more power in the future, all I'd have to do is add LT's and retune it.
Your thoughts?
Seems the cost is going to be about a wash. LT's with an LS6 cam or stock manifolds with a mild cam. Then I figured if I want more power in the future, all I'd have to do is add LT's and retune it.
Your thoughts?
Less weight, more torque, softer lobes, less engine heat (if you have them coated).
Dropping weight off of the nose would be my only motivation for using LTs, but then having to de-tune the car/use a very weak cam to meet NASA power level requirements.
#66
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Did some digging. The iron manifolds weight 28-31 lbs combined. Add some weight for the Y pipe. I have no idea what LT's weight, but it can't be a huge difference.
Redtan, if a stock ls6 makes 340 to the ground stock, then how is my LS1 with LS1 heads and an ls6 cam going to make more power than that? I won't have the ls6 heads which make more power than the ls1 heads.
This is why I'm getting confused. From my searching, the 01-02 ls1's came with an ls6 intake. They had better flowing exhaust manifolds than the 98-00's. The cam changed as well. So, if I pick up an 01-02 ls1, I will have decent flowing manifolds, an ls6 intake, and that's it. I can add an ls6 cam but I won't have ls6 heads. So my power to the ground will be less than a true ls6, right?
Redtan, if a stock ls6 makes 340 to the ground stock, then how is my LS1 with LS1 heads and an ls6 cam going to make more power than that? I won't have the ls6 heads which make more power than the ls1 heads.
This is why I'm getting confused. From my searching, the 01-02 ls1's came with an ls6 intake. They had better flowing exhaust manifolds than the 98-00's. The cam changed as well. So, if I pick up an 01-02 ls1, I will have decent flowing manifolds, an ls6 intake, and that's it. I can add an ls6 cam but I won't have ls6 heads. So my power to the ground will be less than a true ls6, right?
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[QUOTE=redtan;19198964]
TOTALLY AGREE!!
But, decent shorties for our cars (in even 400 series stainless ) are getting harder and harder to find, as many companies which used to make them have now stopped.
Of course, they are a dime a dozen for the 5th gen LS3s/L99s.
Shorties are a good way to drop weight (even over LTs) but not add much power in order to stay within a certain power limit.
TOTALLY AGREE!!
But, decent shorties for our cars (in even 400 series stainless ) are getting harder and harder to find, as many companies which used to make them have now stopped.
Of course, they are a dime a dozen for the 5th gen LS3s/L99s.
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Did some digging. The iron manifolds weight 28-31 lbs combined. Add some weight for the Y pipe. I have no idea what LT's weight, but it can't be a huge difference.
Redtan, if a stock ls6 makes 340 to the ground stock, then how is my LS1 with LS1 heads and an ls6 cam going to make more power than that? I won't have the ls6 heads which make more power than the ls1 heads.
This is why I'm getting confused. From my searching, the 01-02 ls1's came with an ls6 intake. They had better flowing exhaust manifolds than the 98-00's. The cam changed as well. So, if I pick up an 01-02 ls1, I will have decent flowing manifolds, an ls6 intake, and that's it. I can add an ls6 cam but I won't have ls6 heads. So my power to the ground will be less than a true ls6, right?
Redtan, if a stock ls6 makes 340 to the ground stock, then how is my LS1 with LS1 heads and an ls6 cam going to make more power than that? I won't have the ls6 heads which make more power than the ls1 heads.
This is why I'm getting confused. From my searching, the 01-02 ls1's came with an ls6 intake. They had better flowing exhaust manifolds than the 98-00's. The cam changed as well. So, if I pick up an 01-02 ls1, I will have decent flowing manifolds, an ls6 intake, and that's it. I can add an ls6 cam but I won't have ls6 heads. So my power to the ground will be less than a true ls6, right?
Probably the same even for a used LS6 as well.
#69
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Redtan, if a stock ls6 makes 340 to the ground stock, then how is my LS1 with LS1 heads and an ls6 cam going to make more power than that? I won't have the ls6 heads which make more power than the ls1 heads.
This is why I'm getting confused. From my searching, the 01-02 ls1's came with an ls6 intake. They had better flowing exhaust manifolds than the 98-00's. The cam changed as well. So, if I pick up an 01-02 ls1, I will have decent flowing manifolds, an ls6 intake, and that's it. I can add an ls6 cam but I won't have ls6 heads. So my power to the ground will be less than a true ls6, right?
This is why I'm getting confused. From my searching, the 01-02 ls1's came with an ls6 intake. They had better flowing exhaust manifolds than the 98-00's. The cam changed as well. So, if I pick up an 01-02 ls1, I will have decent flowing manifolds, an ls6 intake, and that's it. I can add an ls6 cam but I won't have ls6 heads. So my power to the ground will be less than a true ls6, right?
I'd say your choice is between the true LS6 with some shorties/manifolds or the LS1 with LS6 intake, cam and LTs. Tuning will be the determining factor to get you to the final number that you need to make for your class. Just in the tune alone you can change some 10-15rwhp, so that is your buffer.
Me personally I would do the true LS6 if you can afford it. The block is slightly stronger and the LS6 heads have the lighter valves and are better at oil control. Or do the LS1 block with the LS6 heads so you still get those benefits.
#70
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I agree a true LS6 would be ideal but I doubt I'll be able to find/afford one. Plus I like the idea of running an LS1 with a cam because if I blow it up, it'll be cheaper to replace.
The more I think about it, the more I like the idea of running 01-02 manifolds. I'll try to find an 01-02 LS1 which should already have an LS6 intake, and use some sort of cam that's a little more aggressive than the LS6 cam.
If I use stock manifolds, I'll be able to use a stock Y pipe that uses oval piping for ground clearance. I will probably have the stock cats cut out and have high flow cats welded in (still need to see if that's worth it). Then I can use the stock mid pipe, and even the over the axle section. After that, I'll have the rest cut off and my straight through Borla muffler welded on, exiting straight out the right side under the rear bumper.
I already have the over the axle section off my parts car, I just need the Y pipe. I'd bet I could pick one up for next to nothing from the same place that I'm getting my ls1 from (hawksthirdgen).
Since the manifolds are the limiting factor, the rest of the exhaust (except for muffler and possibly cats) will be just fine. It'll be dirt cheap and will give me the ground clearance I need.
I just need to talk to someone who really knows their stuff and have them pick out a cam that'll do what I need it to do.
The more I think about it, the more I like the idea of running 01-02 manifolds. I'll try to find an 01-02 LS1 which should already have an LS6 intake, and use some sort of cam that's a little more aggressive than the LS6 cam.
If I use stock manifolds, I'll be able to use a stock Y pipe that uses oval piping for ground clearance. I will probably have the stock cats cut out and have high flow cats welded in (still need to see if that's worth it). Then I can use the stock mid pipe, and even the over the axle section. After that, I'll have the rest cut off and my straight through Borla muffler welded on, exiting straight out the right side under the rear bumper.
I already have the over the axle section off my parts car, I just need the Y pipe. I'd bet I could pick one up for next to nothing from the same place that I'm getting my ls1 from (hawksthirdgen).
Since the manifolds are the limiting factor, the rest of the exhaust (except for muffler and possibly cats) will be just fine. It'll be dirt cheap and will give me the ground clearance I need.
I just need to talk to someone who really knows their stuff and have them pick out a cam that'll do what I need it to do.
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Yes, true, as there are very few on here who understand the power needs/demands of road racing, and are just used to suggesting cams which will make max peak dyno power for the top end of the 1/4 mile.
#72
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In my defense I have asked a couple of times what came to use with stock manifolds.
#73
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No. I just figured they aren't necessary for my power goals. The ls1 I'm going to get comes with stock manifolds and I've read that they 01-02 manifolds actually flow pretty well. So I figured I'd save the money on LT's and put it towards a cam that will put me at the power I need, which is 350 rwhp or so. Plus I won't have any ground clearance issues.
Seems the cost is going to be about a wash. LT's with an LS6 cam or stock manifolds with a mild cam. Then I figured if I want more power in the future, all I'd have to do is add LT's and retune it.
Your thoughts?
Seems the cost is going to be about a wash. LT's with an LS6 cam or stock manifolds with a mild cam. Then I figured if I want more power in the future, all I'd have to do is add LT's and retune it.
Your thoughts?
You will make more bottom end and mid-range torque with a stock cam and long tubes than you will with factory manifolds and an aftermarket camshaft.
Personally I'd do the long tubes and then add a small aftermarket camshaft to really benefit from the scavenging effects of the long tube headers, but it might put you past your needed power/weight ratio.
#74
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The short pipes/tubes and horrendous collectors on a factory manifold metaphorically (not literally) suck. They do not scavenge until very very high RPM's whereas your average LS engine long tube header starts to scavenge around 2000-2500rpm depending on cam profile.
You will make more bottom end and mid-range torque with a stock cam and long tubes than you will with factory manifolds and an aftermarket camshaft.
Personally I'd do the long tubes and then add a small aftermarket camshaft to really benefit from the scavenging effects of the long tube headers, but it might put you past your needed power/weight ratio.
You will make more bottom end and mid-range torque with a stock cam and long tubes than you will with factory manifolds and an aftermarket camshaft.
Personally I'd do the long tubes and then add a small aftermarket camshaft to really benefit from the scavenging effects of the long tube headers, but it might put you past your needed power/weight ratio.
As much as I'd like to maximize my power under the curve, I'm not sure it's worth the headache of having no ground clearance.
I can't overshoot my power to weight. If I do, it'll bump me to TT2, requiring me to have like 430 rwhp.
So what do you think? LS6 cam? GM Hot cam?
#78
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Shorty or mid-length headers do not have the same ground clearance issues. Even the tubular LS9 manifolds would be better than factory cast manifolds. LS7 manifolds require extra parts, like whatever the oval-to-round elbow is called.
Any sort real exhaust will be beneficial. Probably more beneficial than a custom cam with a shitty exhaust. An LS6 cam, shorty headers, and true duals is probably all you need to achieve your goals. And it will have a better, more useful powerband than a custom cam trying to breath through cast manifolds, a Y-pipe, and single exhaust.
Any sort real exhaust will be beneficial. Probably more beneficial than a custom cam with a shitty exhaust. An LS6 cam, shorty headers, and true duals is probably all you need to achieve your goals. And it will have a better, more useful powerband than a custom cam trying to breath through cast manifolds, a Y-pipe, and single exhaust.
#80
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I wouldn't use any camshaft with stock manifolds, or shorties that had more than -6 degrees of overlap@.050 on a LS1 engine. Any more than this will create a very large loss in torque under 3500-4000rpm due to the manifolds and shorty headers inability to scavenge spent exhaust gasses and pull fresh intake charge into the cylinder during the overlap event. Thus the longer the overlap event is with these style exhaust systems, the more power will be lost until piston speed can start to create enough depression in the cylinder to bring the engine into tune.