Crazyquik

Well we're far from experts, mostly shadetree engineering here.

Reher-Morrison sales a 1250 hp naturally aspirated crate 622 with a 1.46 rod ratio. Doesn't seem like its hurting them <img src="gr_grin.gif" border="0"> <img src="gr_grin.gif" border="0">

J.

racer7088

Colonel,

""So, ya'll think a 454 CI LS1 with a 1.395 rod to stroke ratio would get a car down the track quicker than a 422 with a 1.575 rod to stroke ratio?""

I'll bet you any day that the 454 will kick the 422s ***! None of this other stuff even matters except what Chris B said about basic integrity. You have to have a minumum CH and the pins and skirts have to clear the crank counterweights. It can get expensive and start to involve lots of heavy metal. My shop will be up and running within the month and we're building some biguns already. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />

LS1derfull

CRrazy Quick, seems to have a good grasp of what is going on with these changes, but i want to know what max rpm are you using for DRCE piston speed formula? Your 6100 fpm sounds low.

Colonel

"Reher-Morrison sales a 1250 hp naturally aspirated crate 622 with a 1.46 rod ratio. Doesn't seem like its hurting them."

VERY good point! If it works for them it should work for us.

racer7088, glad to have your input on this. <img src="gr_images/icons/cool.gif" border="0"> How much harder would the 454 in this case be to turn 8000-8500 RPM than the 401 or 422? Is it feasable? Or would it be better to not strive for such a high revving engine and go with less gear?

Ok, ya'll have me convinced. Truly, bigger IS better! <img src="gr_images/icons/cool.gif" border="0"> So all I gotta do is figure out what would be the limit as far as integrity goes.

[ January 31, 2002: Message edited by: Colonel ]</p>

JimmyKash

[quote]Originally posted by ChrisB:
<strong>As far as all out racing goes, I wouldn't worry about r/s ratio at all. If you are trying to make a motor that lasts 150,000 miles then you might want to shoot for a high r/s ratio for reduced side loading, but for your stated purposes it's really irrelevent. Go for as much bore/stroke as you can while still maintiant the strentgth for your rpm goal. Then Pick a piston ring package/compression height you need for proper operation, then pick a rod.

Chris

[ January 30, 2002: Message edited by: ChrisB ]</strong><hr></blockquote>

Colonel:

READ THE ABOVE, he put it best.

Now i see more of your question....what wins? a Destroked less cube motor or a bigger inch motor with less rpm right?

well there are two different approaches to it but all things being equal, cubes will win.

Destroked motors love to rev and "can" make the same power as stroked motors but they come at more rpm/gearing and sometimes they ET better and sometimes they dont. it is really hard to compare the two because suspension/gearing/tire is totally different for each situation

for you:

build the biggest LS1 you can get, with an intake that wont make the motor fall on its face, with a be-jesus huge cam (for a 454 you could honestly go with a solid roller with specs around 280/290 @ .050 and it would STILL be livable on the street due to the extra inches allowing the bigger duration. Hell i know of 427 SBC's using bigger ones and they are still streetable), keep peak power around 7000-7500rpm and you'll go all the way to the end of the 1/4 with a huge smile on your face and when you come back and look at your timeslip you're be doing this:
<img src="graemlins/fluffy.gif" border="0" alt="[Fluffy]" /> <img src="graemlins/fluffy.gif" border="0" alt="[Fluffy]" /> <img src="graemlins/fluffy.gif" border="0" alt="[Fluffy]" /> <img src="graemlins/fluffy.gif" border="0" alt="[Fluffy]" /> <img src="graemlins/fluffy.gif" border="0" alt="[Fluffy]" />

racer7088

""racer7088, glad to have your input on this. How much harder would the 454 in this case be to turn 8000-8500 RPM than the 401 or 422? Is it feasable? Or would it be better to not strive for such a high revving engine and go with less gear?""

Colonel,

the 4.3 stroke motor will never turn 8500 or at least it won't make power up there. You may be able to get 6300 RPM out of it and shift at 7000 but that's not important. It will be faster requardless. The block may have some integrity issues so it has to be done right at that many inches but you will go faster!

Colonel

Cool, so we'll build it as big as strength will allow, dyno it, and then choose the gearing according to what the numbers tell us.

Any kinda guess on what kinda cam specs might work well for this monstor?

Colonel

"280/290 @ .050"

That sound good to you?

I'll take a wild stab at it and guess a 285/285 .680/.680 110 LSA. Am I in the ballpark or way out in left field here?

racer7088

I think thats way out in left field!

Colonel

LOL! Gettin' carried away aren't I? <img src="gr_grin.gif" border="0">

Any guesses?

racer7088

not many guesses since it would depend on a lot of things. I know exactly what I'd run though with the heads and engine I'm going to do. Are you doing a shootout motor for the next deal ?!?! <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />

Colonel

You mean for the Thunder Racing event? Nah, I may stick with this engine for a long time to come. The CI limit for that event is 440 so this engine we're dreaming up wouldn't be able to compete.

Crazyquik

[quote]Originally posted by LS1derfull:
<strong>CRrazy Quick, seems to have a good grasp of what is going on with these changes, but i want to know what max rpm are you using for DRCE piston speed formula? Your 6100 fpm sounds low.</strong><hr></blockquote>


Came off of Warren Johnson's bio page. States stroke at 3.75", with a redline near 9800 rpm (which is a similar redline to many other figure's I've heard).

J.

JimmyKash

[quote]Originally posted by Colonel:
<strong>"280/290 @ .050"

That sound good to you?

I'll take a wild stab at it and guess a 285/285 .680/.680 110 LSA. Am I in the ballpark or way out in left field here?</strong><hr></blockquote>

well the lift numbers would depend on how well the heads flow. The LSA would also depend on how much the intake can flow too.

if you had a bad *** flowing intake, i'd tell you probably a LSA of like 108* with an IC of around 105...now thats a motor cam

Also, that duration figure is actually SMALL for all those cubic inches. I mean if this is "no street car" you could go with something much bigger.

Someone i know that runs a 377 sbc (destroked 400) has a cam that is 294/304 @ .050 and makes peak power at 8000rpm.

i was just giving a more streetable and "undercam" duration figure...but again the cam depends on everything else in the car so i was just guesstimating

Colonel

Man, this has been a good thread! <img src="gr_images/icons/cool.gif" border="0"> Thanks to all who've participated. It's been VERY thought provocative. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />

Jim98TA

I don't know if this was mentioned anywhere else in the thread or not... The latest Hot Rod magazine has a few articles on stroking, displacement, rod length, etc. I just flipped through it, but didn't read it too close. Just some more info to help ya out maybe...

Colonel

Thanks, I'll check it out next time I'm at the grocery store. <img src="graemlins/gr_devil.gif" border="0" alt="[devil]" />