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What's going on here? Down on power...

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Old 05-08-2008, 02:25 PM
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Originally Posted by Unstang
I think the 3.42 gears are hurting the SOTP meter. We'll see on the dyno for sure though.

I don't. I think the OP just needs to learn that 1st gear is money with a good sized cam and stock gearing

OP,
Wind that bitch out! Any type of roll on should start in 1st gear so long as its below 50mph
Old 05-10-2008, 05:35 PM
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Well got it on the dyno today. It was a SuperFlo dyno as well. The highest reading of the day came from the 2nd pull and that was 345 rwhp and 335 rwtq. Then the #'s started dropping. The last pull was 331/311. I was told these dynos read low but who knows. The A/F was right around 12.8 I believe, not sure on the timing though. I wasn't expecting much from this dyno but when we converted it to a dyno jet the numbers were only up about 20 rwhp. **** bolt on cars make almost that much. I know I can't go on the comparison #'s within the superflo dyno but I was expecting more. I guess I will have to get it to the track and see what it runs.

The curves look good, it never stops making power. Just doesn't make very much. I am pretty disappointed as you can tell. I don't know what else to look into. I have a feeling I will go to the track and trap only 111. The car should make more power than it does and I have no idea where it's at.
Old 05-10-2008, 08:07 PM
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is your block healthy?
But yeah, gtake it to the track see, what it traps, dynos are mostly a dyno tool
Old 05-11-2008, 12:03 AM
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There are other cars that have made good numbers on that dyno, but I still think it is stingy, Scott's car ddin't set the world on fire there either... (No way I'm putting the auto car on there!!!)

The track will tell if it has HP or not!!!
Old 05-11-2008, 12:40 AM
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Originally Posted by RedRocketZ28
So a few weeks ago I added a custom cam 231/232 .612/.592 111+4 and LS6 intake to my otherwise bolt on car with 16k on it. Well before the cam and intake I ran a 13.3 @ 109 with horrid 60' and babying it out of the hole due to bad wheel hop. The car felt pretty strong after the headers.

So fast forward...

Installed cam, drove it untuned for a week or so but never got on it and did not drive it every day. Had someone start tuning on it recently and found it was pig rich, to be expected though I understand. Anyway, after some more tuning the AFR is right around 12.4. Still really rich I know. But, last night I raced my buddies full exhaust car from a 45 mph roll and only beat him by half a car. He got the hit and I passed him while still in 2nd but held that lead and barely inched on him up until 110 or so. What could possibly be wrong with my car? The cam is installed dot to dot, we checked it several times. Could it be something in the tune holding back that much power? Is my car just a turd? Did I mess something up driving on it untuned? The car runs great so it has me baffled. What do you guys think? Thanks.
I would degree your cam at 112/113 degrees for a DD NA car. We did an LS1 swap in a friends 04' truck, and he chose a 116 LSA cam, and it killed the power potential in an otherwise stock motor.
Old 05-11-2008, 12:31 PM
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I assume the block is healthy. I have no reason to think it isn't with only 17k miles on it. The trap speed will tell all. If it traps low, I guess it will all be coming back apart to see what could possibly be wrong.
Old 05-11-2008, 09:23 PM
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All the cams I have seen even close to that size dyno much higher, but like every has already said the track will tell.
Old 05-11-2008, 11:01 PM
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I have another thought on this situation as well. It may be dumb but oh well. I did the LS6 intake at the same time of the cam swap. We ground off the tabs of the intake so I didn't have to buy the coolant crossover kit. Anyway, when we sat the new intake on it did not sit down very well. It would rock back and forth from the front drivers side to the rear passenger side. We could not get it to sit correctly. We though maybe it was the new pads that came with the intake not letting it sit down all the way. Anyway once we tightened the bolts down it stopped rocking obviously. Since the cam install, the car has searched for idle on start up constantly. We have done everything to try and tune it out with no luck. Could I possibly have a vacuum leak and that the intake is not sealing properly? Would the intake not sealing properly cause a decent drop in power? I am just trying to exhaust all my options here before I tear back into the front. I am going to loosen the bolts on the intake to see how it is sitting now. I may even try to switch back to the LS1 intake to see if maybe something is wrong with the LS6 intake. Not sure how something could be wrong though. Anyway, what are your thoughts on this?
Old 05-12-2008, 01:39 AM
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Lean is mean though, so It could run a touch better being lean than rich, although that would cause a lot of long term problems.

You said it ran pig rich before, I would check compression to see if something didn't hydrolock. It's more common than you think.

If compression is right, then call the company that sold you the camshaft and have them explain the cam profile to you. Maybe this will yield some answers.

Other than that, you might be a little to ecstatic about your camshaft. It is a mid lift 115 LSA cam to boot.
Old 05-12-2008, 02:03 PM
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Originally Posted by ReedBooth
Other than that, you might be a little to ecstatic about your camshaft. It is a mid lift 115 LSA cam to boot.

OP says it's on a 111+4 not a 115LSA.
That cam I would think is easy good for 380 and could reach 400.What are you spinning it too? I would love to see a dynograph. I am wondering if something in the valvetrain is not set up right and you are getting valve float. I would assume you swapped out springs and have the proper seat pressure? Pushrods the correct length?? I think I would look at my valvetrain very carefully.
Old 05-12-2008, 06:12 PM
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I will try to get the graph scanned and put it on here. The graph looks normal though. It pulls all the way up to 6500 where the rev limiter is set. No drops or anything to that nature.

As far as valvetrain. That has crossed my mind as well. We did everything on mine as we did my buddies and his is fine. Changed the springs to PRC duals, changed pushrods to 7.425" as to Patrick G's recommendation. I have the cam card here so it really isn't going to do me any good to call up the company I ordered it from.

Yes it did run rich after the cam swap but I never once got on it like so many others on this board have untuned. I putted around in it until it was tuned and not running so rich. I mean the car runs great other than the idle searching on start up and having not much more power than before the cam, haha.
Old 05-12-2008, 09:59 PM
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Here is the graph. Sorry for this shitty picture. #'s are 345/334.

Old 05-13-2008, 09:40 AM
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Originally Posted by RedRocketZ28
I have another thought on this situation as well. It may be dumb but oh well. I did the LS6 intake at the same time of the cam swap. We ground off the tabs of the intake so I didn't have to buy the coolant crossover kit. Anyway, when we sat the new intake on it did not sit down very well. It would rock back and forth from the front drivers side to the rear passenger side. We could not get it to sit correctly. We though maybe it was the new pads that came with the intake not letting it sit down all the way. Anyway once we tightened the bolts down it stopped rocking obviously. Since the cam install, the car has searched for idle on start up constantly. We have done everything to try and tune it out with no luck. Could I possibly have a vacuum leak and that the intake is not sealing properly? Would the intake not sealing properly cause a decent drop in power? I am just trying to exhaust all my options here before I tear back into the front. I am going to loosen the bolts on the intake to see how it is sitting now. I may even try to switch back to the LS1 intake to see if maybe something is wrong with the LS6 intake. Not sure how something could be wrong though. Anyway, what are your thoughts on this?

Dude....If your intake isn't sealing and you had it rocking all around and what not, then you have a SERIOUS problem(s). I know with the FAST 90/90 that if it isn't sealed properly, you could be down as much as 25-30rwhp/tq. Its possible that you may have cracked the intake when cutting the tabs as well?

Good luck to you man.
Old 05-13-2008, 10:56 AM
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Originally Posted by lilbuddy1587
Dude....If your intake isn't sealing and you had it rocking all around and what not, then you have a SERIOUS problem(s). I know with the FAST 90/90 that if it isn't sealed properly, you could be down as much as 25-30rwhp/tq. Its possible that you may have cracked the intake when cutting the tabs as well?

Good luck to you man.

Yea, reread this post and agree. "Hunting for idle" could very well indicate a vacuum leak. I'd pull that sucka off and have a look.
Old 05-13-2008, 11:32 AM
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Are they dynoing it in 3rd with the converter locked? I thought you mentioned somewhere that they did a pull in second?
As for A/F ratios, you wont see any real big difference between 12.8 and 13.2. Sometimes theres not much difference from 12.5 to 13.0.
Old 05-13-2008, 12:06 PM
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I see a couple of things that stick out:

1. The intake manifold. If it's "rocking" then there is something causing that. Get the correct coolant tubes like you should have in the first place. They are cheap and the correct way to install and LS6 intake. One of two things probably going on with this: possible vacuum leak and mismatched manifold-to-intake ports. I'd wager the ports are off slightly, causing terrible flow in some cylinders.

2. Just because it has 17,000 miles does not mean the block is still good. How many people have blow engines with less than 1000 miles?!? Like it was mentioned, check the compression in each cylinder. Make sure you have 8 good cylinders. This is basic stuff, but most assume that their stuff is good. Also, 13.3 ain't flying with mods. Most stock F-bodys can run 13 flat with driver mod.

3. Research the tune on the car. Don't assume anything. Maybe a mail order tune might even be better.

4. Get to the track. Stop worrying about dyno results. As mentioned, dyno's will vary and they are just a tool for tuning for optimal results. You should have dyno'd prior to the install to verify the increases. Obviously you can't do that, but I was curious why the dyno results kept going down. That's strange, unless not allowing any cool down period.

5. Instead of assuming that the push-rods are the right length, buy a push-rod checker and verify the correct length. I thought mine was correct and trusted Predator's recommendation, but they were too long and were bottoming out the lifters. I shimmed the rockers and it ran much better and quieter.

Good luck.
Old 05-13-2008, 06:14 PM
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Thanks for all the help. I will definitely start with the things mentioned and go from there. As far as the intake sealing correctly, I sprayed starter fluid around the intake and throttle body thinking that it would cause the idle to increase due to a leak somewhere but nothing happened. Could it still be off some? I am going to pull it anyway and find out for sure.

The 13.3 I ran @ 109 mph with a 2.3 60'. I ran the car maybe 4 times that day due to terrible wheel hop. I was babying it out of the hole and on the 1-2 shift since it was hopping so bad. That is the reason for the low times. My stock 99 Z28 ran a 13.3 so I know what the cars can do. Believe me, I was disappointed with the times as well.

I am going to start with the intake, see what if anything is wrong there. Then move to checking compression. If those check out then it is time to look at the valvetrain. Would too long of pushrods be robbing me of that much power though? I might even just tear back into it and make sure it is dot to dot as well.
Old 05-18-2008, 09:34 AM
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Checking to see if its 'dot to dot' is a waste of your time. If you're not going to put a degree wheel on it, leave it alone.

Once again, you are assuming that all of your components are correct. If your timing chain is a degree off, your cam cut wrong, and the crank keyway cut a degree off, all the dots might line up fine. You still won't know what the actual VE's are. You mention the cam card, but did you get a cam doctor sheet from your grinder?

I would remove the LS6 manifold and do a visual inspection for cracks or any other potential problems. Switching back to your LS1 manifold is relatively easy and could tell you a lot.

Short of that, it's time to invest in the proper tools (compeasion tester, leakdown tester, degree wheel & dial indicator, pushrod length checker) to see what is really going on. I would venture a guess that your track results could improve, but since you had traction problems before, more power could also make them worse.

Good luck!

Last edited by hammertime; 05-18-2008 at 09:39 AM.
Old 05-19-2008, 04:06 PM
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To answer your question about the cam sheet, I did receive a cam doctor sheet when I got the cam. I have been busy lately and have not had any time to get it to the track or check anything out. Hopefully this weekend I can get the intake removed to check out any potential problems there. Thanks for all the advice though man.




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