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331" De-Stroked LSx.. 8500 rpm??

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Old 07-29-2011, 01:54 PM
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Default 331" De-Stroked LSx.. 8500 rpm??

just like the title says, im thinking about building a semi cheap, super high reving motor. basic plan is to use a 6.0 iron block, 4.8 crank, LS3 heads, solid roller cam
considered going 2 directions, either 12.0:1 compression with nitrous
or about 9.0:1 comp with a pile of boost.

either way i know that i'll need some kind of aftermarket ignition setup, most likely a crank trigger, msd box, distributor, cause i know it will turn more rpm's than what the factory ecu can handle, im NOT going to buy a BS3 or anything of that sort.
so it will be carb'd and probably in the 8500 rpm range.

has anybody built something along these lines?
and what kind of issues have you had to make it work?
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Old 07-29-2011, 02:36 PM
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This idea in various forms come up from time to time. Most folks get talked out of it.

https://ls1tech.com/forums/generatio...go-forged.html
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Old 07-29-2011, 02:56 PM
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Katech does something similar with a 427 block and small stroke in a crate engine
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Old 07-29-2011, 03:10 PM
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What can the factory ECU read for maximum rpm's?
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Old 07-29-2011, 03:21 PM
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Originally Posted by Darkman
This idea in various forms come up from time to time. Most folks get talked out of it.

https://ls1tech.com/forums/generatio...go-forged.html
thats because stock valvetrain is maxxed out at around 7500rpms.

the amount of air pumped with a 331@8500rpms is similar to a 408@6900rpms
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Old 07-29-2011, 03:48 PM
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Originally Posted by sprayinLS1s
just like the title says, im thinking about building a semi cheap, super high reving motor
Those two things don't go hand in hand....."super high" RPM's mean exotic lightweight parts and very expensive valve gear. Also, the risk of expensive catastrophic engine failure goes up exponentially so after you absorb the cost of building something like that the first time you need to be prepared to do it again in the event it grenades (or go a different route at that point).

The reason most people are talked out of it (and into simply building a more reliable larger motor that makes more average power) is because it just makes sense!

The way I see it there are two reasons to build a small CID screamer......your class limited to "X" cubic inch and have no choice.....or you like to be different and have a ton of money to invest in building something more unique and are willing to sacrifice reliability and low/midrange torque for the wail of an 8500+ RPM smallblock.

Just my opinion of course....

-Tony

PS.....Quick story.....back when I was still working at Shafiroffs place we dealt with a guy overseas that had more money than gray matter in my opinion (actually he just had alot of money!....LOL). In a class of cars running 540's to 632 CID bigblocks at the time (no displacement limit), he was bent on running a 440 CID BBC with huge Pro Stock style heads and he routinely turned it to 10,000 RPM.....even now thats a highly respectable RPM figure....more crazy back in the 90's when this took place. He was competitive and it made similar power to the big motors (at 2500 more RPM!), but this guy grenaded a $30,000 BBC at least four times in the thre years I was there to witness it. We pleaded with him to build a bigger engine for less RPM and more reliability and he said he just loved the sound of this motor at 10K and wouldn't trade it for the world. Good thing this guy had the pocketbook to back up what he wanted....hell Scott wasn't complaining either with all the expensive rebuilds!.....LOL (btw....when an engine comes apart at 10K the only parts used in the rebuild is the intake and carbs after you clean the aluminum chips from them!!)



Good luck....hope this PM gives you some food for thought!!

Cheers,
Tony
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Old 07-29-2011, 04:00 PM
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Originally Posted by sprayinLS1s
probably in the 8500 rpm range?
If you were going to do this why only rev to 8500?? Seems like a waste considering there are some 4.00" crank strokers that rev to 7800.

Anybody know what RobZ revs his 388ci motor to??
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Old 07-29-2011, 04:31 PM
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I think he takes it to like 8800rpms.
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Old 07-29-2011, 05:52 PM
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Originally Posted by awd2rwd
If you were going to do this why only rev to 8500?? Seems like a waste considering there are some 4.00" crank strokers that rev to 7800.

Anybody know what RobZ revs his 388ci motor to??
SAM and HKE have turned 4" strokers up over 9600RPM.
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Old 07-29-2011, 06:14 PM
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cheap/budget high revving builds..... love these topics. They don't exist

My vote is 6.0 iron block, stock crank, quality rods/pistons, doweled main caps and thick deck heads with medium sized hyd cam for boost.

Good driveability with crazy potential under boost.

I would love to hear about someone running the "Andreas" Swedish guy's head gaskets making 1000rwhp+. They are $400/set I believe.

Last edited by gnx7; 07-29-2011 at 06:29 PM.
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Old 07-29-2011, 06:34 PM
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distributor on an LS1? has that ever been done? why?
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Old 07-29-2011, 06:45 PM
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RPM's = ruins peoples motors...

my question is WHY do you want to take cubic inches (and power) away from your combo? and FYI theres alot more to RPM than stroke, and you can build a 6.0 to rev to the moon just like you can build a 331 to rev to the moon. i'll take the same parts, and the same money. guess which one will make more power?

perhaps you should buy a honda?
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Old 07-29-2011, 06:50 PM
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amen.
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Old 07-29-2011, 06:54 PM
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Originally Posted by RezinTexas
distributor on an LS1? has that ever been done? why?
its been done, but again, why? i thought people convert dist engines to COP? weird.
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Old 07-29-2011, 07:19 PM
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Originally Posted by RezinTexas
distributor on an LS1? has that ever been done? why?
Originally Posted by kmracer
its been done, but again, why? i thought people convert dist engines to COP? weird.
Distributors are used on high RPM motors where the stock reluctor wheel doesn't have enough resolution to produce accurate spark.
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Old 07-29-2011, 07:28 PM
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i was being a little sarcastic. obviously a BD dist is a great idea. i actually didnt read where he said " aftermarket ignition setup, most likely a crank trigger, msd box, distributor"

i was thinking he ment an msd cam driven GMPP setup, which is silly IMO.
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Old 07-30-2011, 01:07 AM
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For the smart ***'s:
The Z-28 in my sig pic is mine, it has a 365 iron block, running a 76mm turbo on a rear mount setup that I built from scratch, its a 9 sec car on pump gas with ice cold a/c and can be daily driven, so I know what that combo is capable of
I also had a +5000# truck that ran low 11s on a stock bottom LS1, both vehicles of which i did every bit of work on and tuned with efi live, so I'm not ignorant of the platform.

For those who made quality posts, you are greatly appreciated

The reason I was thinking about this is cause I may get a notch back stang or gen 3 f-body to build for a grudge car, so it's going to be light weight since it won't have creature comforts, basically a licensed race car, that's why I'm not too worried about average power. If it was a DD street car, i wouldnt have made this thread, cause Id put a 6.0 with a cam in it and been done. Besides it'll be nice to show what the same cubes in a LSx can do versus some of the 331/347 SBF stang boys. Takes away their crutch of crying about cubic inches, I hear alot of that **** at the track.
Also know a guy with a 6.0 LS in a notch back and I know how fast that car is for a budget build and only going to 6300 rpm.

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Old 07-30-2011, 01:29 AM
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Originally Posted by KCS
SAM and HKE have turned 4" strokers up over 9600RPM.
True, but i don't have the backing to build a motor like theirs, or have my own machine shop/ dyno for doing R&D

The bottom end won't be too bad to build, but like Tony said, the valve train is going to be the hard/expensive part to get right.
With the smaller cubes I think the LS3 heads and a Vic Jr should keep up on air flow, so that will save alot of money.

I've seen a few different ignition setups on the all motor LSX cars, but I dont know the pros/cons of them.
Cause like some have said, it would be pointless to do a motor like this and not go well over 8000, I do agree with that.
Hell my 6.0 goes to 7200... lol
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Old 07-30-2011, 01:30 AM
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I think it's a cool concept. Nothing like the sound of an 8000+ rpm small block. I do agree with the other guys about not budget friendly though. That kind of rpm requires very lightweight parts in the rotating assembly and that stuff is by no means "budget." I'd be curious to see what kind of power it made with a monster cam.

Guy I know has a 349 CI fox body. Spins that thing to 8000 RPM's and there is nothing in the world that sounds like that. He raced another freind in a H/C/nitrous LS1 camaro to his stangs all motor setup and actually put a few cars on him FROM A ROLL. Very impressive to say the least.
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Old 07-30-2011, 02:02 AM
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A stock 4.8 crank with some weight reduction ought to work, they have plenty of over lap on the mains and rod journals, so it should be almost indestructible. With the shorter stroke, the balancing won't be as critical as it would on a 3.62/4.00 crank, since it's not going to have the same inertia, and the rod/piston speed won't be as high for the same given rpm as a bigger stroke. (I know balancing is still very important)

It's basically a modern day DZ302 like the 69 Z-28, and I've had the privilege of riding one of those cars and I know they could put a hurtin on the same car w/ a 427 BBC
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