Stroking the LSA engine

[Rikki Tikki Tavi]

I have intentions on installing a Kenne Bell 3.6lc on my ZL1. But I want to build the LSA first. I was curious to know if you could stroke the stock LSA motor safely.

Or should I get an RHS or another aftermarket shortblock

Thanx for any advice

[mylftft]

Yes you can safely stroke it, its a 6.2L Chevy LS block, its the same as any LS3, LS9 & so on. Plenty of stroker options that interchange with all those motors. Check out ADM performance on this site, Andy has done a ton of stroker kits & engine swaps in the ZL1, he has dyno sheets posted so you can see the power levels the different combos achieved. I'd check that out before deciding on a blower swap, the 1.9 can get to surprising power levels. ADM has a car they did with the 1.9 blower on top of a 427, check the dyno sheet that goes with it, power under the curve & max power is just awesome!

[jessrayo]

The biggest snag is going to be the transmission. You have to put in a different crankshaft and the LSA has a different output on the crank from the other LS motors which basicially means that you have to swap to one of the other LS transmissions when you swap the stroked crankshaft.

[KD Innovations]

Forging the LSA will be a good option to a point but if you want to run a lot of boost, I would suggest a 6 bolt design. Somewhere around 800 RWHP I would begin to look at a stronger 6 bolt block.

For a PD blower, strocking is not really that necessary.

[The Baron]

Lol at these posts^^^&

1. Do your homework. No aftermarket blower works on the zl without crazy mods. . Acc dont fit, and the cowl has to be cut badly.
2.stroking the motor with the stock blower does not work because the blower cant sustain the motors appetite.
3. If you feel the need to make 750 wheel it can ne done with the factory blower.
4. If you do decide to go through with a big monster build any of tje crankshaft companies ALREADY make a forged lsa crank in4.00 stroke.

[jessrayo]

Originally Posted by The Baron

Lol at these posts^^^&


2.stroking the motor with the stock blower does not work because the blower cant sustain the motors appetite.
3. If you feel the need to make 750 wheel it can ne done with the factory blower.

The stock blower (1.9L) can only feed so much air and to make much more than 750 horsepower you would need a bigger blower. Now 750 wheel horsepower is between 875 and 900 on an engine dyno. No matter how you look at it, it takes a lot of work to get there. With more displacement you do not need as much boost or octane to get the same power readings. In theory this will be safer for the longevity of the motor, and blower, especially if the stroker kit uses forged parts.

[The Baron]

But you are still moving the, or trying to move the same amount of air. The problem is the blower literally becomes a bottleneck.

you STILL have to spin the blower harder to move that air.. I have a little knowledge about this. I would like to hear from a couple big builders but in any other setup if the blower is the limiting factor on 370 ci, putting it on top of 427 ci is not going to do anything but choke the bigger motor.

. If youblook at the history bof the LSA, you will find a bunch of guys who spent tens of thousands converting lsa motors with big whipples and changing and hacking and either selling the project, parting it out or going back to the stock blower. .

[The Baron]

I have a forged motor in my zl.. stock cubic inch stock crank (FORGED) good rods and pistons.

[Rodslnger]

Originally Posted by The Baron

But you are still moving the, or trying to move the same amount of air. The problem is the blower literally becomes a bottleneck.

you STILL have to spin the blower harder to move that air.. I have a little knowledge about this. I would like to hear from a couple big builders but in any other setup if the blower is the limiting factor on 370 ci, putting it on top of 427 ci is not going to do anything but choke the bigger motor.

. If youblook at the history bof the LSA, you will find a bunch of guys who spent tens of thousands converting lsa motors with big whipples and changing and hacking and either selling the project, parting it out or going back to the stock blower. .

You are correct. On my 2000 camaro f1a 21lb 408 makes 800+ new motor 427 f1a have to pulley it down and only make 13lb at max impeller speed and makes 900 ran out of blower. I build all my motors.

[ZL1RHINO]

Hey baron so you kept your stock crankshaft what hp can it handle safely and tje do they have a website. Thanks

[ayousef]

Originally Posted by The Baron

But you are still moving the, or trying to move the same amount of air. The problem is the blower literally becomes a bottleneck.

you STILL have to spin the blower harder to move that air.. I have a little knowledge about this. I would like to hear from a couple big builders but in any other setup if the blower is the limiting factor on 370 ci, putting it on top of 427 ci is not going to do anything but choke the bigger motor.

. If youblook at the history bof the LSA, you will find a bunch of guys who spent tens of thousands converting lsa motors with big whipples and changing and hacking and either selling the project, parting it out or going back to the stock blower. .

Not everybody

Well putting a relatively small blower on a bigger CI motor can make more power because:

- you will end up with a lower (boost) figure at the same amount of CFM or airflow compared to the smaller motor. Now because youre running less boost you can either jack up the spark advance, or even better raise the compression ratio. So in a nutshell you wont be flowing more air into the engine, but you will be able to make more mechanical horsepower via added spark advance or compression.

so for example: both blowers spinning at the same speed on a:

- 6.2l motor your'e pushing 14psi of boost

-7.0l pushing 10psi of boost.

but then you also have to consider that the 427 will loose on the mpg if that's important. My 427 truck does 8mpg cruising around with a TVS2300 427, and that bothered me a lot.

[The Baron]

Well using the 1.9 on anything over 400ci seems silly to me. Jyst by uping head flow to around 350 cfm, medium size cam and 2 inch headers my blower being spun at 24500 rpm barely is making 16#s... and its not getting there until 63-6400 rpm.. and the blower is in my op max ported with a 105 nw on it... you stick a 427 and the 400cfm heads to go with it and I think even with the blower maxed out you are going to be at max boost reslly early in the rpm band and have the equivalent of sticking a beach towel in the air cleaner.


as far as stock crank goes.. its a factory forged and hardened piece that will support a 1000 hp without blinking. The lsa and ls9 crank arecworks of factory art.

[jessrayo]

There is no replacement for displacement. I think the adage is true. A stroker motor will have more torque across the powerband, with the same blower speeds, boost pressures will be lower and therefore generate less heat. You can get power in many different ways.... I think stroking the motor is a good option.

[Rikki Tikki Tavi]

Originally Posted by jessrayo

The biggest snag is going to be the transmission. You have to put in a different crankshaft and the LSA has a different output on the crank from the other LS motors which basicially means that you have to swap to one of the other LS transmissions when you swap the stroked crankshaft.

Wow. I didnt know id have to change the transmission as well. Suddenly, stroking isnt an option. Or perhaps I could get a custom billet crankshaft.