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I LOST 20ftlbs. And 5 hp!

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Old 04-20-2017, 08:14 PM
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Originally Posted by ddnspider
Either way, I agree with WS6store, props for going back and getting the dyno time again with the midlengths instead of just bashing SE and leaving it open ended like most would have.
Thanks again. I would also like to give props to Mike at New Era Performance. Once your initial tune is done they only charge you 150.00 for a retune. He was shocked at the drop in power (evethough it had nothing to do with his tune,it was just parts being swapped) he only charged me 1 hr shop rate for the second tune. These guys are top notch and have many custom products all fabricated up in house for the whole Ls line up.
Old 04-20-2017, 08:18 PM
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Looking at your dyno graph again the old pulls were much smoother, while the new graph is rougher. How many miles are on the valve springs and when's the last time you did maintenance stuff like fuel filter, etc.
Old 04-20-2017, 08:43 PM
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Meh, a gain of 5ft lbs and 6HP by going to longtubes isn't enough to justify the cost of the longtubes as is. Maybe with a different cam, heads or intake the results might be better.
Old 04-20-2017, 09:05 PM
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Originally Posted by ddnspider
Looking at your dyno graph again the old pulls were much smoother, while the new graph is rougher. How many miles are on the valve springs and when's the last time you did maintenance stuff like fuel filter, etc.
I keep up on all the maintenance, oil was just changed about 200 miles ago, I use Penzoil Platinum, ngk plugs, the fuel filter has been about 10000 miles, I will probably change that soon. Cam, springs, morel 5315 lifters, oil pump, timing chain,valve seals, were all done last year, 3,000 miles or so. The only thing in question could be the BTR trunion upgrade I did 2 yrs ago. I haven't checked them since they went in. I saw the thread in the Comp ones going bad. I may have take a look at those. I also checked all my accessories. WP, ALT, AC clutch, PS pump and idler pulley. They all were good.
To me the graph with the LTs is pretty rough compared to the Macs. Why.... I don't know.
Old 04-21-2017, 04:49 AM
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I always liked the mac,s , fit very well and never threw any 02 sensor codes
with my old setup . Do the SE headers fit as good as the mac,s ?
Old 04-21-2017, 06:25 AM
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Originally Posted by andrewss
I always liked the mac,s , fit very well and never threw any 02 sensor codes
with my old setup . Do the SE headers fit as good as the mac,s ?
The Macs y pipe has better ground clearance, they also did not slide right in as did the SE LTs. I had to remove the steering shaft on both. Spark plugs were easier to access on the Macs as well. There is some rasp with the Macs around 2500 rpm, where the SE had none. The SEs had that faint ticking sound like an exhaust leak, where the Macs were much quieter up front.
If I put the LTs back on I will cut the back of the y merge off where it reduces down to 2.75" to join up with the cat back which opens back up to 3" and make it all 3". The Macs y was 2.75" all the way back.
Old 04-21-2017, 07:44 AM
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That's interesting. I've done about 3 sets of the SE 1 7/8 and we didn't remove the steering on any of them and they droped in.
Old 04-21-2017, 07:58 AM
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Originally Posted by wannafbody
Meh, a gain of 5ft lbs and 6HP by going to longtubes isn't enough to justify the cost of the longtubes as is. Maybe with a different cam, heads or intake the results might be better.
If you already have the mac's yeah with a bolt on car it may not be worth it to upgrade to 1 7/8 long tubes.but if you don't​have headers at all it's worth putting the 1 7/8 long tubes on just in case you all more aggressive heads and cams setup.
Old 04-21-2017, 09:19 AM
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Originally Posted by tech@WS6store
Track times can be manipulated by weight reduction, gears, converters, line locks...the list goes on. Even the weather that day can effect it. Hardly any of that would show on a dyno. You are saying a loss on the dyno of 20 ft lbs (and what appears to be all over a loss) and no gain in hp can equal a faster time at the track...then i do not believe you.
Dynos have weather stations and correction factors for those discrepancies. Drag strips you ran what you ran.
I understand your points but that's why those things have to be accounted for with drag times as well. You can't change the weight or gears or add other equipment like line locks and then compare drag times before and after. It's about only changing 1 variable at a time and getting multiple runs before and after that variable.

You can also measure DA and correct all the runs for it as it changes.

Personally I've seen much larger swings in dyno numbers (especially automatics) than I have properly measured and corrected track times.
Old 04-21-2017, 09:44 AM
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If you would have said you slowed down at every increment at the drag strip after the changes, that would have been surprising.

Showing a negligible difference on a dyno, months apart with different dyno settings is not mind blowing. Don't hang your hat on dyno numbers.
Old 04-21-2017, 10:24 AM
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Originally Posted by Hi-Po
If you would have said you slowed down at every increment at the drag strip after the changes, that would have been surprising.

Showing a negligible difference on a dyno, months apart with different dyno settings is not mind blowing. Don't hang your hat on dyno numbers.
Exactly. Again, LTs are proven to make power. If a comparison shows otherwise, then look at the comparison for discrepancies. How thats not obvious I dont get.
Old 04-21-2017, 12:03 PM
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Only a gain above 5700 and honestly a paltry gain at that for long tubes seems hardly worth it to me. Maybe on a larger cam it would be different. Too many variables to even say yes or no to.
If someone bought 2 separate cams and had only that gain, yall would be sacrificing the second cam designer.
Old 04-21-2017, 01:38 PM
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Originally Posted by tech@WS6store
Only a gain above 5700 and honestly a paltry gain at that for long tubes seems hardly worth it to me. Maybe on a larger cam it would be different. Too many variables to even say yes or no to.
If someone bought 2 separate cams and had only that gain, yall would be sacrificing the second cam designer.
If the second cam went slower, in the real world (see: local drag strip); then yes. For the life of me I can't understand this sites infatuation with dyno numbers. They mean next to nothing.
Old 04-21-2017, 01:49 PM
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That has been answered before. Because not everyone has access to a track. Or are set up to drive on a track. In getting a new cam or headers youll need a tune. Normally that ends in a dyno. And for the most part it doesnt go beyond that. As far as the new street outlaws fad, there is no time on that just 1 vs other which is normally a driver race or all in the suspension setup.
Before and after times would be great as any point of information is good, but not always possible.

Plus how else can you bench race against the mustang guys without numbers?
Old 04-21-2017, 02:05 PM
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Track mph with DA correction is far more accurate than comparing dynos. OP did a great job with his back to back to back, but it's widely know that you throw ET out the window at the track when comparing mods, but mph doesn't lie except for very specific situations like high hp and no traction.
Old 04-21-2017, 04:09 PM
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Average power wins races, peak power wins dyno contests
Old 04-21-2017, 05:56 PM
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Originally Posted by cdubbzz
Average power wins races, peak power wins dyno contests
clarify that a bit. More average power over the rpms used during racing wins. Gaining hp at 2500 means nothing in a drag race as the car will never see it except MAYBE on launch.
Old 04-22-2017, 07:40 PM
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Originally Posted by ddnspider
clarify that a bit. More average power over the rpms used during racing wins. Gaining hp at 2500 means nothing in a drag race as the car will never see it except MAYBE on launch.
Depends on how the car is used. Midrange torque is great for a street car, high end HP is better for a drag car.
Old 04-22-2017, 07:56 PM
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Originally Posted by wannafbody
Depends on how the car is used. Midrange torque is great for a street car, high end HP is better for a drag car.
did you read cdubzzz post that I made that statement about? Specifically racing.....
Old 04-23-2017, 07:32 AM
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I started thinking about this thread on my way home from work and I got home, walked in the door and punched my cat. Now I have a large vet bill to pay. Thanks OP.


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