Anyone run 108 LSA cams in boat before? 700 HP DYNO proven combos welcome...
08-31-2016, 09:28 PM
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I hear what your saying and was along the same thought process. I do however know for a fact that Jim v is running 236/242 plus a minus on a 565 tunnel ram 784 hp-@6k engine. Goes to show with superior flowing heads you don't necessarily need all that duration even on a bigger CI engine. I know I've brought this up in a post before however I honestly believe it can't be stressed enough.
08-31-2016, 09:32 PM
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I know Cigrocket made 687 hp with a 315 head and 741 cam, I was going to copy that recipe, wish I did lol
I hear what your saying and was along the same thought process. I do however know for a fact that Jim v is running 236/242 plus a minus on a 565 tunnel ram 784 hp-@6k engine. Goes to show with superior flowing heads you don't necessarily need all that duration even on a bigger CI engine. I know I've brought this up in a post before however I honestly believe it can't be stressed enough.
08-31-2016, 09:36 PM
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mines 241/[email protected] 681/663 lift on 112.... from 5400-5900 it made only 6 more HP... was supposed to be able to spin current props 6000... they stop at 5500..
Curious what specs are for your current cam. I'm putting the finishing touches on an mk combo i started like 2 years ago. I have a 502 gen vi with a 540 stroker kit in it and the afr 325's. He set me up with a 113.1 lsa, 238 duration intake with .66394 lift and a 243.3 duration exhaust with .64567. This was supposed to be spec'd for a dry exhaust combo
08-31-2016, 09:48 PM
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That's what I'm wondering, I wonder if he went too far with the cam? Mine is a 540 as well too and seems to be a good step or two back from his in regards to those numbers. That said I haven't dyno'd it or anything yet so no clue what this combo even makes
08-31-2016, 10:07 PM
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I see the post now lol
thought you meant old thread...
that's what I figured from beginning, then everyones telling me I should be in 250 range @.050..
so many answers lol
thought you meant old thread...
that's what I figured from beginning, then everyones telling me I should be in 250 range @.050..
so many answers lol
08-31-2016, 10:28 PM
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Everyone freaks out about duration at .050 , and LSA . The old school of thought that has been embedded in all of our minds, is that a "narrow" lsa, will idle like crap, and have a "peaky" power band, and a wide LSA, will have a "smooth idle", and flat power band. BUT, that isn't always the case. You can have a wider LSA cam, that has more overlap, than a narrower LSA cam. Also, a cam that might need to idle at 1100RPM in a 454 cubic inch, might idle nicely at 700RPM in a 572ci.
Everyone freaks about too much duration, because basically, as duration goes up, the intake valve keeps closing later, and later ,and later. At idle and low speeds, you pay a penalty for that. According to David Vizards book, he claims that being off 5 degrees on the overlap triangle, can have a MUCH greater effect, than being off 5 degrees of intake valve's closing point.
If you take a look at two crane hyd rollers, with identical .050 duration numbers, one being a 110LSA, one being a 114 LSA, you will see, that while the 110 LSA cam has more "overlap", the 114 LSA intake valve, is closing later in the cycle. Contrary to what most think, a 108 LSA cam, may be better suited to a low compression BBC , than a 114 LSA in a low compression BBC. High compression ratios, can help scavenge the exhaust out of the cylinder. Low compression engines, can need some help there. This is where the additional overlap helps build power.
Every notice something? The merc HP500 Cam, was what, a 222/230, 110 LSA cam, and the 500EFI cam, was a 230/236 114 LSA cam? Both engines made nearly identical power, at the same RPM band roughly. The Hp500 got a bad rap for reversion, blamed on the 110 LSA, but really, the problem was in the tailpipe risers. Irregardless, the HP500, had 8* deg less intake duration, and 6 * less exhaust duration, but still made the power at 5200RPM.
According to Vizard, his advice is, when a long duration cam is used, the LSA is usually spread to give the better idle quality for the street. But the solution isn't really to spread the LSA, its to shorten the duration. Now, you end up seeing a car that builds better torque, and gets down the track faster, as it has the right amount of overlap and timing events, rather than a "crutched" combo in an effort to seek out a smooth idle.
One of the things he talks about, and that makes sense to me, is that a PROPERLY selected flat tappet, will always outperform, a POORLY selected roller. Everyone these days gets jazzed up over peak valve lift numbers, and ramp rates. They think the key to making power is big lift and fast lobes, but none of that helps, if the valves aren't opening and closing at the right times, and the right amount of overlap isn't there.
Tim, as far as your search for 700HP 540 recipes, they are out there all over the place. 1.3HP per ci, from a N/A bbc on pump gas, is nothing exotic. Like that 496ci I was telling you about earlier the shop by me built. It was making 645HP at 6200RPM, using GM Iron rect port heads! I've seen several guys here build 496 strokers, with aftermarket good flowing heads, that couldn't break 600hp. What those builds had in common, was cams ALOT shorter, than the cam that was used in this build. Again, everyone is worried that if they put any duration in an engine, low speed torque is gonna be a turd. That 496ci with a healthy hyd roller, was still making 575ft lbs at 4000, and 590 at 5000. The best heads aren't gonna make up for a poor cam choice. And 680 lift cams with the wrong valve events, will never beat out a 600 lift cam, with the right valve events.
Hate to say it, but everyone on oso laughed Chris Straub and Scott Foxwell right out of here. I was pretty skeptical when offshoreexcursion went to straub for a cam for his NA 572's. Once I saw the dyno sheets, I was surprised, and the goal was pretty much met. What was even more impressive, was that the cams idled well, sound nasty as hell with the tractor headers, accelerate really good, and , last week, won his class in the shootout, at 111MPH in a 36ft vee bottom with power robbing wet sump drives. He's logged quite a few hours on them so far, and no issues . While a 750HP 572ci engine isn't anything crazy these days, prior to offshoreex's build, I was led to believe straub and foxwell were a couple dildos who shouldn't be changing a set of spark plugs without supervision. I've seen quite a few N/A custom cammed bbc combos here over the years, and very few are in the 1.3HP per ci range. Most seemed to have 1 thing in common, short cams.
Tim, is reversion is your concern, obviously fully dry tails are the answer. There's plenty of sound solutions on the market today, if that is an issue. I am running dry jacketed stellings, with Gaffrig Superflo air operated mufflers. They quiet down just fine. With the mufflers closed, it sounds like it has a pair of 330's in it.
08-31-2016, 10:43 PM
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Thx Joe, and you know you and I talk a lot, so we will work together on solutions as I decide to change things, you have been a great help and a good friend, one of the better I met here on OSO I really appreciate it..
I think it generally depends on the overall build, as far as what kind of overlap it likes/needs.
Everyone freaks out about duration at .050 , and LSA . The old school of thought that has been embedded in all of our minds, is that a "narrow" lsa, will idle like crap, and have a "peaky" power band, and a wide LSA, will have a "smooth idle", and flat power band. BUT, that isn't always the case. You can have a wider LSA cam, that has more overlap, than a narrower LSA cam. Also, a cam that might need to idle at 1100RPM in a 454 cubic inch, might idle nicely at 700RPM in a 572ci.
Everyone freaks about too much duration, because basically, as duration goes up, the intake valve keeps closing later, and later ,and later. At idle and low speeds, you pay a penalty for that. According to David Vizards book, he claims that being off 5 degrees on the overlap triangle, can have a MUCH greater effect, than being off 5 degrees of intake valve's closing point.
If you take a look at two crane hyd rollers, with identical .050 duration numbers, one being a 110LSA, one being a 114 LSA, you will see, that while the 110 LSA cam has more "overlap", the 114 LSA intake valve, is closing later in the cycle. Contrary to what most think, a 108 LSA cam, may be better suited to a low compression BBC , than a 114 LSA in a low compression BBC. High compression ratios, can help scavenge the exhaust out of the cylinder. Low compression engines, can need some help there. This is where the additional overlap helps build power.
Every notice something? The merc HP500 Cam, was what, a 222/230, 110 LSA cam, and the 500EFI cam, was a 230/236 114 LSA cam? Both engines made nearly identical power, at the same RPM band roughly. The Hp500 got a bad rap for reversion, blamed on the 110 LSA, but really, the problem was in the tailpipe risers. Irregardless, the HP500, had 8* deg less intake duration, and 6 * less exhaust duration, but still made the power at 5200RPM.
According to Vizard, his advice is, when a long duration cam is used, the LSA is usually spread to give the better idle quality for the street. But the solution isn't really to spread the LSA, its to shorten the duration. Now, you end up seeing a car that builds better torque, and gets down the track faster, as it has the right amount of overlap and timing events, rather than a "crutched" combo in an effort to seek out a smooth idle.
One of the things he talks about, and that makes sense to me, is that a PROPERLY selected flat tappet, will always outperform, a POORLY selected roller. Everyone these days gets jazzed up over peak valve lift numbers, and ramp rates. They think the key to making power is big lift and fast lobes, but none of that helps, if the valves aren't opening and closing at the right times, and the right amount of overlap isn't there.
Tim, as far as your search for 700HP 540 recipes, they are out there all over the place. 1.3HP per ci, from a N/A bbc on pump gas, is nothing exotic. Like that 496ci I was telling you about earlier the shop by me built. It was making 645HP at 6200RPM, using GM Iron rect port heads! I've seen several guys here build 496 strokers, with aftermarket good flowing heads, that couldn't break 600hp. What those builds had in common, was cams ALOT shorter, than the cam that was used in this build. Again, everyone is worried that if they put any duration in an engine, low speed torque is gonna be a turd. That 496ci with a healthy hyd roller, was still making 575ft lbs at 4000, and 590 at 5000. The best heads aren't gonna make up for a poor cam choice. And 680 lift cams with the wrong valve events, will never beat out a 600 lift cam, with the right valve events.
Hate to say it, but everyone on oso laughed Chris Straub and Scott Foxwell right out of here. I was pretty skeptical when offshoreexcursion went to straub for a cam for his NA 572's. Once I saw the dyno sheets, I was surprised, and the goal was pretty much met. What was even more impressive, was that the cams idled well, sound nasty as hell with the tractor headers, accelerate really good, and , last week, won his class in the shootout, at 111MPH in a 36ft vee bottom with power robbing wet sump drives. He's logged quite a few hours on them so far, and no issues . While a 750HP 572ci engine isn't anything crazy these days, prior to offshoreex's build, I was led to believe straub and foxwell were a couple dildos who shouldn't be changing a set of spark plugs without supervision. I've seen quite a few N/A custom cammed bbc combos here over the years, and very few are in the 1.3HP per ci range. Most seemed to have 1 thing in common, short cams.
Tim, is reversion is your concern, obviously fully dry tails are the answer. There's plenty of sound solutions on the market today, if that is an issue. I am running dry jacketed stellings, with Gaffrig Superflo air operated mufflers. They quiet down just fine. With the mufflers closed, it sounds like it has a pair of 330's in it.
Everyone freaks out about duration at .050 , and LSA . The old school of thought that has been embedded in all of our minds, is that a "narrow" lsa, will idle like crap, and have a "peaky" power band, and a wide LSA, will have a "smooth idle", and flat power band. BUT, that isn't always the case. You can have a wider LSA cam, that has more overlap, than a narrower LSA cam. Also, a cam that might need to idle at 1100RPM in a 454 cubic inch, might idle nicely at 700RPM in a 572ci.
Everyone freaks about too much duration, because basically, as duration goes up, the intake valve keeps closing later, and later ,and later. At idle and low speeds, you pay a penalty for that. According to David Vizards book, he claims that being off 5 degrees on the overlap triangle, can have a MUCH greater effect, than being off 5 degrees of intake valve's closing point.
If you take a look at two crane hyd rollers, with identical .050 duration numbers, one being a 110LSA, one being a 114 LSA, you will see, that while the 110 LSA cam has more "overlap", the 114 LSA intake valve, is closing later in the cycle. Contrary to what most think, a 108 LSA cam, may be better suited to a low compression BBC , than a 114 LSA in a low compression BBC. High compression ratios, can help scavenge the exhaust out of the cylinder. Low compression engines, can need some help there. This is where the additional overlap helps build power.
Every notice something? The merc HP500 Cam, was what, a 222/230, 110 LSA cam, and the 500EFI cam, was a 230/236 114 LSA cam? Both engines made nearly identical power, at the same RPM band roughly. The Hp500 got a bad rap for reversion, blamed on the 110 LSA, but really, the problem was in the tailpipe risers. Irregardless, the HP500, had 8* deg less intake duration, and 6 * less exhaust duration, but still made the power at 5200RPM.
According to Vizard, his advice is, when a long duration cam is used, the LSA is usually spread to give the better idle quality for the street. But the solution isn't really to spread the LSA, its to shorten the duration. Now, you end up seeing a car that builds better torque, and gets down the track faster, as it has the right amount of overlap and timing events, rather than a "crutched" combo in an effort to seek out a smooth idle.
One of the things he talks about, and that makes sense to me, is that a PROPERLY selected flat tappet, will always outperform, a POORLY selected roller. Everyone these days gets jazzed up over peak valve lift numbers, and ramp rates. They think the key to making power is big lift and fast lobes, but none of that helps, if the valves aren't opening and closing at the right times, and the right amount of overlap isn't there.
Tim, as far as your search for 700HP 540 recipes, they are out there all over the place. 1.3HP per ci, from a N/A bbc on pump gas, is nothing exotic. Like that 496ci I was telling you about earlier the shop by me built. It was making 645HP at 6200RPM, using GM Iron rect port heads! I've seen several guys here build 496 strokers, with aftermarket good flowing heads, that couldn't break 600hp. What those builds had in common, was cams ALOT shorter, than the cam that was used in this build. Again, everyone is worried that if they put any duration in an engine, low speed torque is gonna be a turd. That 496ci with a healthy hyd roller, was still making 575ft lbs at 4000, and 590 at 5000. The best heads aren't gonna make up for a poor cam choice. And 680 lift cams with the wrong valve events, will never beat out a 600 lift cam, with the right valve events.
Hate to say it, but everyone on oso laughed Chris Straub and Scott Foxwell right out of here. I was pretty skeptical when offshoreexcursion went to straub for a cam for his NA 572's. Once I saw the dyno sheets, I was surprised, and the goal was pretty much met. What was even more impressive, was that the cams idled well, sound nasty as hell with the tractor headers, accelerate really good, and , last week, won his class in the shootout, at 111MPH in a 36ft vee bottom with power robbing wet sump drives. He's logged quite a few hours on them so far, and no issues . While a 750HP 572ci engine isn't anything crazy these days, prior to offshoreex's build, I was led to believe straub and foxwell were a couple dildos who shouldn't be changing a set of spark plugs without supervision. I've seen quite a few N/A custom cammed bbc combos here over the years, and very few are in the 1.3HP per ci range. Most seemed to have 1 thing in common, short cams.
Tim, is reversion is your concern, obviously fully dry tails are the answer. There's plenty of sound solutions on the market today, if that is an issue. I am running dry jacketed stellings, with Gaffrig Superflo air operated mufflers. They quiet down just fine. With the mufflers closed, it sounds like it has a pair of 330's in it.
08-31-2016, 11:20 PM
#29
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My 454's 9.6:1 made 590HP 565TQ @ 6500RPM's (that's where I stopped the dyno it was still making 8HP/pull) with my old wedged Merlin heads. With JimV's cast heads and porting I was probably 600+. Never went back to the dyno when I switch heads, but the boat picked up speed. Dry to the tip exhaust. Idled great at 650RPM's locked out timing
This cam made ~680 in a 502 10:1 ported Pro1's.
This cam made ~680 in a 502 10:1 ported Pro1's.
08-31-2016, 11:31 PM
#30
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I recently bought performance trends engine software, i been crunching cam numbers, intake runner length etc and looking at theoretical results, im getting ready to extensively dyno a mild compression 540 w full out cncd afr heads that flow well over 400 cfm. What im seeing is to get the hp peak to go to about 6000 where i want to be its going to need a fuk ton of cam. I inputed my old blower cam which came from bob m and has duration in the 250/260 range and .380 lobe lift snd with unrestricted intake comes up with numbers in the 700 range around 6000, when i start putting in durations like you have i see numbers in mid 600's at 5500 ish but earlier tq peaks. My boat is a 33 stepped hull scarab so i need top end hp not so much mid range tq so im going to start dynoing with that cam since it looks like it will possibly make good hp na (and i already own it).
