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LS3 Carbed build

General engine tech -- Drag Racing to Circle Track

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CGT
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Re: LS3 Carbed build

Post by CGT » Fri Feb 14, 2020 7:19 am

MadBill wrote:
Thu Feb 13, 2020 9:15 pm
randy331 wrote:
Thu Feb 06, 2020 9:50 am
steve cowan wrote:
Thu Feb 06, 2020 1:23 am
Randy,
Are you thinking that there might be more area available below peak torque if lifter is not collapsing some??
Well, you never really know what that hyd lifter does. How much collapse etc.
Less spring may increase actual time/area/lift on the running engine up to the limits of valve train control.

I guess I could try it on the lsx 454 when I dyno it?? It will be a lower rpm engine but same type of lift.
I have higher seat/rate springs for it. I could put the stock ones back on for a few pulls.

Randy
How about just cranking the hot preload down to a few thous for a quick pull? True, the rocker/pushrod geometry might be sub-optimal but it should be good enough to highlight any lifter collapse effects and if you keep the revs in check there would be no chance of the potentially huge pump-up causing valve/piston contact..
Non-adjustable valvetrain.
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Re: LS3 Carbed build

Post by steve cowan » Sun Feb 16, 2020 2:21 am

Chad,
i was looking at rules for masters of motors for this year and looking at Eric Roycraft winning race engine challenge LS3 with tunnel ram and 2 x carbs.
with your LS3 and a compression rule of 12.5:1,do you have an opinion on where your engine would sit in the competition??
hope you don't mind me asking :D
i personally think 1.6 ft/lbs cube and 2hp/cube would still be within reach even with a compression decrease. :?:
steve c

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Re: LS3 Carbed build

Post by CGT » Sun Feb 16, 2020 4:03 pm

steve cowan wrote:
Sun Feb 16, 2020 2:21 am
with your LS3 and a compression rule of 12.5:1,do you have an opinion on where your engine would sit in the competition??
Are you asking how I think my engine would have fared at REC with the compression decrease? Or master of motors?
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Re: LS3 Carbed build

Post by randy331 » Mon Feb 17, 2020 10:28 am

steve cowan wrote:
Sun Feb 16, 2020 2:21 am
Chad,
i was looking at rules for masters of motors for this year and looking at Eric Roycraft winning race engine challenge LS3 with tunnel ram and 2 x carbs.
with your LS3 and a compression rule of 12.5:1,do you have an opinion on where your engine would sit in the competition??
hope you don't mind me asking :D
i personally think 1.6 ft/lbs cube and 2hp/cube would still be within reach even with a compression decrease. :?:
Steve, in it's current state chad's engine would have been a second place rec engine I think. Or could be with a little work.
One thing, as it is now, is Chad's engine is peaking too high in rpm for the rec. The comp would need lowered and rpm lowered. Both would hurt the HP numbers some. But going to a fast lobe solid roller at the lift limit of the rec would more than offset the comp loss I think.
Be interesting to see what a sheet metal intake and 2 4825 Braswells or 2 1050s would run like on it.
To get it up to Roycroft's first place engine would take some more development.

Randy

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Re: LS3 Carbed build

Post by steve cowan » Tue Feb 18, 2020 12:24 pm

randy331 wrote:
Mon Feb 17, 2020 10:28 am
steve cowan wrote:
Sun Feb 16, 2020 2:21 am
Chad,
i was looking at rules for masters of motors for this year and looking at Eric Roycraft winning race engine challenge LS3 with tunnel ram and 2 x carbs.
with your LS3 and a compression rule of 12.5:1,do you have an opinion on where your engine would sit in the competition??
hope you don't mind me asking :D
i personally think 1.6 ft/lbs cube and 2hp/cube would still be within reach even with a compression decrease. :?:
Steve, in it's current state chad's engine would have been a second place rec engine I think. Or could be with a little work.
One thing, as it is now, is Chad's engine is peaking too high in rpm for the rec. The comp would need lowered and rpm lowered. Both would hurt the HP numbers some. But going to a fast lobe solid roller at the lift limit of the rec would more than offset the comp loss I think.
Be interesting to see what a sheet metal intake and 2 4825 Braswells or 2 1050s would run like on it.
To get it up to Roycroft's first place engine would take some more development.

Randy
Thanks Randy,
i was reading about the LS3 that won REC in engine builder magazine and thought would be a good conversation piece,i can see there would require a lot of rework as you pointed out.
steve c

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