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Thanks for reporting back!
I thought LS motors liked big splits. I always see 12°-13°, like 235°-248°, especially on carb LS builds. I could be wrong, but I believe that is what I read. |
Originally Posted by Rookie
(Post 4680543)
I thought LS motors liked big splits. I always see 12°-13°, like 235°-248°, especially on carb LS builds. I could be wrong, but I believe that is what I read.
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You do the typical things like make a few runs without the flame arrestor on ? try a known good carb ? make sure proper voltage to box and coil ? Known good coil? etc/etc
You would think a true 1050 carb wouldn't restrict enough to cause 1.2-1.3:Hg" ? or maybe it as the flame arrestor ? I've seen some unconventional intake vs exhaust cam lobes on a cam do this too. .050" 's where conventional. Probably 6-10 of them.They basically caused a 'sticking a potato in the exhaust' effect. LOL. |
Originally Posted by SB
(Post 4680551)
You do the typical things like make a few runs without the flame arrestor on ? try a known good carb ? make sure proper voltage to box and coil ? Known good coil? etc/etc
You would think a true 1050 carb wouldn't restrict enough to cause 1.2-1.3:Hg" ? or maybe it as the flame arrestor ? I've seen some unconventional intake vs exhaust cam lobes on a cam do this too. .050" 's where conventional. Probably 6-10 of them.They basically caused a 'sticking a potato in the exhaust' effect. LOL. |
Thr only other thing im wuestioning is the annular carb. Ive heard of them vaporizing the fuel effectively killing the oxygen in the plenum. Never seen it. |
Like my great grandpappy would say “ Im too drunk to taste this chicken”. |
No, but seen them go rich at higher rpm, zapping power. I did not see/read you had annular. Interesting a 408LS with a 4150 carb needed annular boosters, but what the hell do I know. :)
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Originally Posted by SB
(Post 4680557)
No, but seen them go rich at higher rpm, zapping power. I did not see/read you had annular. Interesting a 408LS with a 4150 carb needed annular boosters, but what the hell do I know. :)
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Your cam use the same lobe intake and exhaust ?
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Originally Posted by SB
(Post 4680564)
Your cam use the same lobe intake and exhaust ?
237/237 114.5+4.5 .621/.612 |
I'm glad we are talking about this. Can you PM me with .100" and .200" durations and seat durations for both intake and exhaust lobes ?
You may just have one of those funk azz potatoe in the tailpipe cams.that I mentioned running into above...Post #203..that are near impossible to tune right.....and flat line....just maybe.....we'll see.... |
Originally Posted by SB
(Post 4680568)
I'm glad we are talking about this. Can you PM me with .100" and .200" durations and seat durations for both intake and exhaust lobes ?
You may just have one of those funk azz potatoe in the tailpipe cams.that I mentioned running into above...Post #203..that are near impossible to tune right.....and flat line....just maybe.....we'll see.... |
Was looking at the "AERA NIGHTHAWK " LS build just now . '
408ci 4.03x4.00 CNC ported trick flow heads 11.69:1 compression 243/251 .624/.624 114 LSA Engine made 629HP at 6500RPM. Your engine has almost a full point less compression, STOCK cylinder heads, 6* less intake duration, 14* less exhaust duration, same bore and stroke. Im just not seeing the original claim that this combo would make 625hp by 6000rpm, with the ingredients it has. The power seems to be fairly in the ballpark for what it is. ' I am currently building (4) LS engines for a twin 28 Eliminator Daytona Tall Deck and 32 Sunsation Dominator. Figured I would let the cat out of the bag for future reference as a go to for people that attempt this. These engines will have prak torque at about 5000 and peak power at 6200. Roughly 625hp 600tq and make a 525efi look like a fool the entire powerband. We will be rev limiting them at 6200rpm. Remember these are not bbc and can easily sustain that rpm for hours on end. |
NightHawk LS 408 Dyno RunRPM Torque (Ft.-Lbs.) HP3600 466.8 340.03700 473.5 355.3 3800 494.7 374.9 3900 508.8 391.4 4000 516.8 407.8 4100 524.6 426.1 4200 534.9 443.1 4300 539.7 463.0 4400 543.0 482.5 4500 548.6 496.8 4600 552.8 510.1 4700 554.0 522.8 4800 554.9 535.3 4900 555.0 546.8 5000 555.5 558.5 5100 555.6 570.0 5200 555.0 580.7 5300 552.0 588.5 5400 549.8 594.7 5500 547.1 600.5 5600 544.9 605.6 5700 540.0 609.0 5800 537.3 611.0 5900 532.6 612.4 6000 527.5 619.5 6100 524.2 623.7 6200 520.2 625.8 6300 511.9 628.6 6400 508.4 629.0 6500 502.9 629.5 6600 489.4 628.6 6700 479.7 625.3 6800 472.7 623.3 ' 'https://cimg2.ibsrv.net/gimg/www.off...d9286efd1.jpeg |
If your engine made 549HP at 6200 with 30* of timing, Id say thats not too shabby for a stock LS3 headed 408ci. That VE% is pretty good for what it is.
One common thing we in the marine world often are used to , is fairly poor VE numbers, fairly high BSFCs, and fairly low HP to ci ratios. The LS guys poo poo our big blocks for that. ' Your engine made 1.34Hp per ci. Thats pretty good. Might say, well it makes a 525EFI look like a fool. Sure, the 525 only makes around 1.09hp per ci. However, the 525EFI, is also 8.75:1, and makes that 1.09HP per ci, about 1000 RPM lower than that LS. Now, build a 502ci, with 10.8:1 compression, custom cam , and spin it to 6200rpm. At 1.34hp per ci, that would be 672hp. Really not a tough feat for a 502 with almost 11:1 compression. With a 4" stroke, decent valvetrain parts , that 502 will live a long time turning 6200rpm. Its been done many times. The end of the day, the LS engine has many nice features from a design standpoint. But its not magic. You still need to move X amount of air, to make X amount of HP. That is why the big block chevy is still a favorite in many forms of motorsports today, from marine, to drag racing, truck pulling, or the guy who simply likes blowing his tires off thru the first 4 gears on a saturday night. |
Your engine has 100 less cubic inches, less cam, worse exhaust, and the same head flow as a 525. IDK where you expected 100hp to magically appear from. |
Originally Posted by MILD THUNDER
(Post 4680585)
If your engine made 549HP at 6200 with 30* of timing, Id say thats not too shabby for a stock LS3 headed 408ci. That VE% is pretty good for what it is.
One common thing we in the marine world often are used to , is fairly poor VE numbers, fairly high BSFCs, and fairly low HP to ci ratios. The LS guys poo poo our big blocks for that. ' Your engine made 1.34Hp per ci. Thats pretty good. Might say, well it makes a 525EFI look like a fool. Sure, the 525 only makes around 1.09hp per ci. However, the 525EFI, is also 8.75:1, and makes that 1.09HP per ci, about 1000 RPM lower than that LS. Now, build a 502ci, with 10.8:1 compression, custom cam , and spin it to 6200rpm. At 1.34hp per ci, that would be 672hp. Really not a tough feat for a 502 with almost 11:1 compression. With a 4" stroke, decent valvetrain parts , that 502 will live a long time turning 6200rpm. Its been done many times. The end of the day, the LS engine has many nice features from a design standpoint. But its not magic. You still need to move X amount of air, to make X amount of HP. That is why the big block chevy is still a favorite in many forms of motorsports today, from marine, to drag racing, truck pulling, or the guy who simply likes blowing his tires off thru the first 4 gears on a saturday night. |
Originally Posted by hogie roll
(Post 4680589)
I agree. Everyone’s been furiously debating why LS adoption is not widespread in boats, in a nut shell it’s because BBCs are really hard to beat. One thing I have yet to see, is how the LS will stand up to offshore abuse. Meaning, in a big offshore that runs in BIG water, where the crankshaft is seeing tremendous shock loading from props coming in and out of the water, trying to twist the crankshaft out of the block. Flat water runs, dyno runs are one thing, a 41 Apache gettin it in big water with some saccenti like throttling going on, is another. |
Originally Posted by MILD THUNDER
(Post 4680585)
If your engine made 549HP at 6200 with 30* of timing, Id say thats not too shabby for a stock LS3 headed 408ci. That VE% is pretty good for what it is.
One common thing we in the marine world often are used to , is fairly poor VE numbers, fairly high BSFCs, and fairly low HP to ci ratios. The LS guys poo poo our big blocks for that. ' Your engine made 1.34Hp per ci. Thats pretty good. Might say, well it makes a 525EFI look like a fool. Sure, the 525 only makes around 1.09hp per ci. However, the 525EFI, is also 8.75:1, and makes that 1.09HP per ci, about 1000 RPM lower than that LS. Now, build a 502ci, with 10.8:1 compression, custom cam , and spin it to 6200rpm. At 1.34hp per ci, that would be 672hp. Really not a tough feat for a 502 with almost 11:1 compression. With a 4" stroke, decent valvetrain parts , that 502 will live a long time turning 6200rpm. Its been done many times. The end of the day, the LS engine has many nice features from a design standpoint. But its not magic. You still need to move X amount of air, to make X amount of HP. That is why the big block chevy is still a favorite in many forms of motorsports today, from marine, to drag racing, truck pulling, or the guy who simply likes blowing his tires off thru the first 4 gears on a saturday night. |
Originally Posted by MILD THUNDER
(Post 4680591)
I really dont understand the "LS CRAZE". That engine platform came out 22 years ago. Its not exactly some "NEW" technology. Its a great engine, that had some design improvements over the old small block engines. Sure they have made some great engines evolving from the early LS1. Theres more technology into a 4 cylinder Honda engine. Its a pushrod V8.
One thing I have yet to see, is how the LS will stand up to offshore abuse. Meaning, in a big offshore that runs in BIG water, where the crankshaft is seeing tremendous shock loading from props coming in and out of the water, trying to twist the crankshaft out of the block. Flat water runs, dyno runs are one thing, a 41 Apache gettin it in big water with some saccenti like throttling going on, is another. |
Originally Posted by hogie roll
(Post 4680587)
Your engine has 100 less cubic inches, less cam, worse exhaust, and the same head flow as a 525. IDK where you expected 100hp to magically appear from. |
Originally Posted by mggdoors
(Post 4680569)
cam card The cam card just shows .050" durations. Also shows intake lobe area to be a little larger than exhaust. Does not mean a ton ,, yet, lobe info will show more. Again,looking for seat, .100" and .200". This will be found in the master lobe catalog. Let me know when you get this. Thanks. |
Originally Posted by MILD THUNDER
(Post 4680583)
Was looking at the "AERA NIGHTHAWK " LS build just now . '
408ci 4.03x4.00 CNC ported trick flow heads 11.69:1 compression 243/251 .624/.624 114 LSA Engine made 629HP at 6500RPM. Your engine has almost a full point less compression, STOCK cylinder heads, 6* less intake duration, 14* less exhaust duration, same bore and stroke. Im just not seeing the original claim that this combo would make 625hp by 6000rpm, with the ingredients it has. The power seems to be fairly in the ballpark for what it is. ' |
Originally Posted by SB
(Post 4680605)
The cam card just shows .050" durations. Also shows intake lobe area to be a little larger than exhaust. Does not mean a ton ,, yet, lobe info will show more. Again,looking for seat, .100" and .200". This will be found in the master lobe catalog. Let me know when you get this. Thanks. |
Originally Posted by sutphen 30
(Post 4668820)
I have a hard time believing your getting 625hp out of that 222 camshaft,sorry.
now you have a 237/237 cam in there now? time for some heads and bigger cam,unless you gonna stay at 500hp. |
Probably a cam change during the build. I'm not sure how those exh ports flow but I am surprised there's not another 6-8 deg more on the exh duration. |
Originally Posted by mggdoors
(Post 4680606)
Will the cam i currently have make those numbers? Probably not. But one that note you will notice I changed paths on the cam after that post to prevent the need for dry exhaust and avoid reversion. I do see it making 570-580 which I am ok with. look up some dyno pulls on an ls3/l92 and you will see that NONE of them fall off on the power like mine currently is around 5200. When we clean that up results will be alot more impressive. In the mean time they are just pineapples. A good example to look at is a ct525 ls3 factory gm crate engine. 6.2 liters cranking out 540-550 with stock heads and a little 226/236 cam. Now Imagine that with 408 cubes and a bigger cam. I would say I should definitley be making a bunch more power than that engine eveywhere, which currently I am not.
Im still not sure why you thought you would make 625hp at 6200, when that engine is similarly specd, just less cubic inch, but only makes 533hp at 6600. theres much smarter guys than me on this thread, just seems to me if 625 horse power is what you want, you need better heads , more cam, more rpm. Of course youre limited by reversion/exhaust. Thats where heads would help. Less duration needed , when you have heads that flow really well. Stock LS3 heads dont exactly flow very well. My 392 Hemi in my challenger makes 485hp at 6000rpm. Sae power with all accessories, factory exhaust, etc. On a typical dyno, with long tube headers, its easily over 500hp. The cam is fairly short duration, but the apache heads flow like an aftermarket big block chevy head. I follow you with the single pattern cam concept, as it can help build torque in the lower rpm range. I remember brian tooley talking about this topic. In his testing, he found the crossover point, where the dual pattern cam on a LS started making more power, was much lower than most think. I forget the exact number, but wanna say it was in the 2500-3000rpm range. With such a poor intake to exhaust flow ratio on the stock LS3 heads, i just dont think its single pattern worthy. Now if they had excellent exhaust ports, it might be worth it. Please dont take offense to my or others criticism towards your combo. Its just shop talk. Looking forward to your next move and its results. |
Originally Posted by MILD THUNDER
(Post 4680637)
Yes, the CT3 makes 533hp, at 6600rpm, with a 226/236 cam. It also has a significantly smaller stroke crank. The cam that pulls to 6600 in that engine, wont be the same cam that will pull to 6600 in yours. You need more cam to get to 6600.
Im still not sure why you thought you would make 625hp at 6200, when that engine is similarly specd, just less cubic inch, but only makes 533hp at 6600. theres much smarter guys than me on this thread, just seems to me if 625 horse power is what you want, you need better heads , more cam, more rpm. Of course youre limited by reversion/exhaust. Thats where heads would help. Less duration needed , when you have heads that flow really well. Stock LS3 heads dont exactly flow very well. My 392 Hemi in my challenger makes 485hp at 6000rpm. Sae power with all accessories, factory exhaust, etc. On a typical dyno, with long tube headers, its easily over 500hp. The cam is fairly short duration, but the apache heads flow like an aftermarket big block chevy head. I follow you with the single pattern cam concept, as it can help build torque in the lower rpm range. I remember brian tooley talking about this topic. In his testing, he found the crossover point, where the dual pattern cam on a LS started making more power, was much lower than most think. I forget the exact number, but wanna say it was in the 2500-3000rpm range. With such a poor intake to exhaust flow ratio on the stock LS3 heads, i just dont think its single pattern worthy. Now if they had excellent exhaust ports, it might be worth it. Please dont take offense to my or others criticism towards your combo. Its just shop talk. Looking forward to your next move and its results. |
Good point MT with superior flowing heads less duration necessary. Good example is Valakos 565 ci peaks hp at 6K with a little 236/244 duration cam. Running solid rollers to boot. Makes complete sense. Endeavor32 and I took a not so cozy temp lake MI ride today in his 37 AT but did some prop changing and had fun regardless. Mike said my face was redder than my maga hat. Lol.... Regardless keep at it doug and I know you will. Nothing ventured nothing gained. Get some more deposits for doors and get some heads coming. You might even be able to get away with your existing cams. Good thread. |
April 6th ride in lake MI
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Coolthat you guys are able to do it. Full face helmet looks dumb when riding in a boat but it sure is warm !!!
My lake is still frozen, Our snow is almost gone,but holding out in the shade. My dirt roads still have sections with frost in them. mggdoors - sunday better than week-day to call or ????? |
Originally Posted by getrdunn
(Post 4680646)
Good point MT with superior flowing heads less duration necessary. Good example is Valakos 565 ci peaks hp at 6K with a little 236/244 duration cam. Running solid rollers to boot. Makes complete sense. Endeavor32 and I took a not so cozy temp lake MI ride today in his 37 AT but did some prop changing and had fun regardless. Mike said my face was redder than my maga hat. Lol.... Regardless keep at it doug and I know you will. Nothing ventured nothing gained. Get some more deposits for doors and get some heads coming. You might even be able to get away with your existing cams. Good thread. |
That will definately wake it up. I assume that's at .600 + - Ya I went with cnc brodix on my 421 sbc. It was night and day difference from the old ported camel back closed chamber heads. All takes time and money but in the end as long as you and the engines are happy that's all ultimately matters. Do do you still have your custom BBC blower cams you ordered prior to change in builds? |
Originally Posted by getrdunn
(Post 4680667)
That will definately wake it up. I assume that's at .600 + - Ya I went with cnc brodix on my 421 sbc. It was night and day difference from the old ported camel back closed chamber heads. All takes time and money but in the end as long as you and the engines are happy that's all ultimately matters. Do do you still have your custom BBC blower cams you ordered prior to change in builds? |
What would be reall estimated diference in power betwen this nice engine from thread and original Chevrolet LS3 376/480 480hp V8 Crate Engine Partsworld Performance or Chevrolet LS3 376/525 V8 Engine Partsworld Performance with marine exhausts like http://www.californiamarine.com/part...tnumber=123215 ?
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I would love to see your results with a good cathedral head. I think the LS3 style heads are not what you want in a boat. I eagerly watch every comparison I find where they compare motors with both heads and the cathedral always wins out in the torque range applicable to us. That was why I posted the link to that max effort build earlier in your thread. They could have easily chosen some wild LS7 style heads, but opted for cathedral heads to get the flat trq curve and lower rpm range. I think some of the guys posting after your results missed that link. Granted they did not have to worry about reversion or crappy exhaust, but other than that that would have made an awesome boat motor. |
Originally Posted by fastestbowtie
(Post 4681249)
I would love to see your results with a good cathedral head. I think the LS3 style heads are not what you want in a boat. I eagerly watch every comparison I find where they compare motors with both heads and the cathedral always wins out in the torque range applicable to us. That was why I posted the link to that max effort build earlier in your thread. They could have easily chosen some wild LS7 style heads, but opted for cathedral heads to get the flat trq curve and lower rpm range. I think some of the guys posting after your results missed that link. Granted they did not have to worry about reversion or crappy exhaust, but other than that that would have made an awesome boat motor. |
Verified cam timing. Survey says it is within .5 degrees of centerline. Out she comes. I have decided since I am going to be forced to add split thus adding overlap that I am going to step this **** up a notch. I know it will have to be dry exhaust at this point so screw it. Will give specs within the hour |
Originally Posted by mggdoors
(Post 4680602)
There was a guy a few years back that put them in a raceboat that replaced some big hp bigblocks. A cat if I recall. He seamed to love them compared to the bigblocks. I would be interested to find him on here and ask how they are holding up.
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Originally Posted by hogie roll
(Post 4681770)
They were very high end 750hp LS7 builds. At least 427s, maybe bigger I don’t recall. A skater in Michigan had them. |
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