New numbers :(
Originally Posted by slimcracka
like said above the # dont look bad.. the oil in the exhaust is prolly blow by.. do you have an upgraded PVC system or a catch can..the oil is comon on these motors. hell when i did my ls6 intake upgrade the factory on was like poring oil out of the ports when i took it off and set it on the ground...and if there is oil in the combustion chamber then that could hurt the #s a lil bit ..i say sea foam it and put a AMW catch can on it..just my .02 thow
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From: Lumberton, TX
Those numbers sound about right for a 98 with that many miles. From what I understand, 98 models didn't flow as well as newer LS1's. I got 400rwhp and 387rwtq with mods in sig and tuned it myself with the predator and on a hot day with not tricks and 315's out back.
Your torque curve looks similar to mine but just generally lower in every respect. Your high end tq/hp carry out a little farther then mind but the heads will explain that (once again, the numbers are just lower). When I dynoed this cam I performed a SOTP tune with my personal ls1 edit. I diddn't even have a wide band but tuned off of audible pinging, plugs, and knock retard, which everything looked good. My car was an 01 with around 30,000miles on it though. I had oil in my intake ports (from pcv system) but no, or not a significant amount, of blow by judging by my consumption of oil and lack of smoking. Keep at it man, I think you'll find the culprit of the missing power soon enough.
Also, for what it's worth a 99 z28 dynoed the same day on the same dyno as I with an exhaust beeing his only modification and a six speed and he made 300rwhp so I don't think my numbers are inflated or anything.
P.S. Doesn't your exhaust consist of a true dual setup? From who? What mufflers?
Also, for what it's worth a 99 z28 dynoed the same day on the same dyno as I with an exhaust beeing his only modification and a six speed and he made 300rwhp so I don't think my numbers are inflated or anything.
P.S. Doesn't your exhaust consist of a true dual setup? From who? What mufflers?
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It's kind of hacked up. But it consists of a tsp dual system. Then previous owner put high flow cats in and swapped the bullets for sweet thunders. Then I took the cats off. I'll be doing some tests here soon. I'm wanting to know what's holding the power back. I'm hoping it's not the rings, or something else that would reguire some big money. Probably going to get the 6.0L pcv valve and that should stop the pcv system from leaking in oil. Then I'll do a leakdown and find if any oil is leaking through the seals or rings.
Originally Posted by 777
It's kind of hacked up. But it consists of a tsp dual system. Then previous owner put high flow cats in and swapped the bullets for sweet thunders. Then I took the cats off. I'll be doing some tests here soon. I'm wanting to know what's holding the power back. I'm hoping it's not the rings, or something else that would reguire some big money. Probably going to get the 6.0L pcv valve and that should stop the pcv system from leaking in oil. Then I'll do a leakdown and find if any oil is leaking through the seals or rings.
Well exhaust flow is critical for this cam to work like mine did, remember I had oppen headers with collector extensions (reminance of a horrible y-pipe) when I dynoed. I don't think that is going to result in the missing 30-40 hp/tq though. I don't know how well the sweet thunder mufflers flow and if the pipes are mangled up real good this isn't going to help the performance of this cam. One way to see if the exhaust is the culprit is to simply drop it, find extensions, and then re-dynoe. If you find a lot of missing power then your exhaust system will need to be dealt with (better flowing mufflers such as bullet type deals, correcting any screwed up mangled pipe issues). You are on the right track with the compression test though, that should indicate if that's an issue or not. I don't think the oil in the intake port from the pcv system is a huge issue but it may help you find additional power as well by stopping that problem. When I dynoed mine I was having oil come in through the pcv system.
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From: Jacksonville, FL
Hmm, no one does any good custom work on duals around here. To be hones with you I want to get a trans am rear bumper and route the exhaust out the back. I really want to keep the sound of these mufflers so I'd have to find something just like them as far as sound.
Yeah, I got my duals from lanes way back when, but never had a chance to dyno this cam with those duals on. My SOTP meter which is usually pretty accurate said that there was almost no loss in performance when I swapped the duals on over the collector extensions. I had the 3" twister mufflers though which I believe flow pretty well, not as good as a ture bullet, but good enough for what I was doing. See if you can find any flow results of those sweet thunder mufflers. If you do enough research you may be able to find some out there (not just on tech, but on other sites as well). Good luck and let me know of any way I can help!
Nick
Nick
Well according to the good word of Mr. Vizard if you want a no compromise exhaust system you must have mufflers that flow a total of 2.2 (or 1.1 per muffler) cfm per open headered horsepower of the car. So by applying this rule of thumb you can see a muffler flow of around 550 cfm per muffler is needed her. Anyone know the flow of these mufflers?
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I think that's a big debate. No one has flow numbers for these mufflers. It's all speculation. I haven't seen one sliver of evidence about these things regarding flow.
Originally Posted by 777
I think that's a big debate. No one has flow numbers for these mufflers. It's all speculation. I haven't seen one sliver of evidence about these things regarding flow.
