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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 »

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 »

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. :?:
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Re: LS3 Carbed build

Post by CGT »

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 »

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 »

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.
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Re: LS3 Carbed build

Post by 202ci EH »

Sorry I’m a bit of a lurker I don’t post much.

Awesome results! It’s stout by any means. Hurry up and put some rods in it and keep turning it!!!!!
Just a thought but I wonder what the lifter wheel speed is like with the .700 wheels and a large base circle??

I finally put a driveshaft in mine and turned the rpms up. It’s a chassis dyno so hard to bring the numbers across but we’ve had thousands of ls’s on there and it’s a hard bitch.

Engines done 2000 street km’s and the valve tips look fine at .632 lift though I’m not pushing it like you are.

Made 461hp to the tyres @ 7400 and it’s still charging, not giving up yet. Didn’t want to turn it higher on stock rods and cast pistons, too expensive to junk it, an ls3 block in aus is worth near 3k....
It picked up 30 or more rwkw with the intake spacer but I think it had more to do with continuing the runner shape than the actual volume?

I didn’t expect it to peak so high even at 376ci, maybe the heads aren’t too bad? Converter might be tricky for a street car...
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Re: LS3 Carbed build

Post by 202ci EH »

...
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Re: LS3 Carbed build

Post by 202ci EH »

https://www.facebook.com/1027396179/pos ... 47324/?d=n

It’s on our 98 unleaded pump gas too, took 28* timing.
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Re: LS3 Carbed build

Post by steve316 »

that looks like a very clean install; nice work.
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Re: LS3 Carbed build

Post by CGT »

steve316 wrote: Sun Mar 08, 2020 11:14 am that looks like a very clean install; nice work.
I agree, everything looks very legit 202. The black everything is really cool. Is a Calais an Oldsmobile in Aus? Very nice results, very clean everything. Weird that you mounted the brake booster and master cylinder on the passenger side though.....must be a complex system to get all that over to the left side pedal lol 8)
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Re: LS3 Carbed build

Post by swampbuggy »

Hello CGT, doing well i hope. Was your last sentence written on a serious note or a joking note ? Mark H.
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Re: LS3 Carbed build

Post by CGT »

swampbuggy wrote: Sun Mar 08, 2020 9:57 pm Hello CGT, doing well i hope. Was your last sentence written on a serious note or a joking note ? Mark H.
I was joking, its weird to see all that stuff on the other side. :lol:
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Re: LS3 Carbed build

Post by GARY C »

CGT wrote: Sun Mar 08, 2020 9:21 pm
steve316 wrote: Sun Mar 08, 2020 11:14 am that looks like a very clean install; nice work.
I agree, everything looks very legit 202. The black everything is really cool. Is a Calais an Oldsmobile in Aus? Very nice results, very clean everything. Weird that you mounted the brake booster and master cylinder on the passenger side though.....must be a complex system to get all that over to the left side pedal lol 8)
I just assumed he either had really long leggs or was married. :)
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Re: LS3 Carbed build

Post by 202ci EH »

CGT wrote: Sun Mar 08, 2020 9:21 pm
steve316 wrote: Sun Mar 08, 2020 11:14 am that looks like a very clean install; nice work.
I agree, everything looks very legit 202. The black everything is really cool. Is a Calais an Oldsmobile in Aus? Very nice results, very clean everything. Weird that you mounted the brake booster and master cylinder on the passenger side though.....must be a complex system to get all that over to the left side pedal lol 8)
Thank you sir’s ! It feels more natural driving on this side \:D/
But! It means the starter motor is always a problem with the steering shaft and headers, starter gets a dodgy conversion to the l/hs.

Not Olds! It’s a Holden commodore ~ VK. Calais is just the luxury model.
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Re: LS3 Carbed build

Post by CGT »

15960356_large.jpg
Calais :D This is the image that pops in my head when I hear that word.

202, would you be interested in the pistons out of my LS3?
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