Re: Best bore and stroke combo?
[Re: sgcuda]
#2395280
10/30/17 11:01 AM
10/30/17 11:01 AM
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Joined: Jan 2003
Posts: 14,545 So. Burlington, Vt.
fast68plymouth
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I built a 920hp 572 that went in a 2750lb race weight Daytona. In decent air it went a best of 8.33@ 165.
Using the Moroso chart, if you were trying to get to 7.95 from the 8.33 starting point....... You could theoretically get there by removing 400lbs, or adding 160hp(1080hp).
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Best bore and stroke combo?
[Re: sgcuda]
#2395291
10/30/17 11:21 AM
10/30/17 11:21 AM
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Joined: Jan 2012
Posts: 2,760 Stuttgart, Arkansas
rickseeman
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Stuttgart, Arkansas
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My Jerry Bickle Neon with carbon fiber body, carbon fiber rear brakes, MW drilled axles etc weighed 2200. It had a Ray Barton 572 (975 hp) and ran low 8's I think. (I only ran it in the 1/8 mile.) Normally 5.25 but a best of 5.15.
Last edited by rickseeman; 10/30/17 02:32 PM.
2011 Drag Pak Challenger
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Re: Best bore and stroke combo?
[Re: sgcuda]
#2395465
10/30/17 03:18 PM
10/30/17 03:18 PM
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Joined: Jan 2003
Posts: 19,599 Las Vegas
Al_Alguire
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Well we spin the 572 in the dragster to 8000-8100 with no issues. Will those heads support a 572 at that RPM, I doubt it. Bore is what makes power, stroke moves it around. If you are truly building an all out engine. We have continually dropped the stroke in the heads up car and we make MORE power now with less stroke than we did before. For next year it will be same cubes at a shorter deck height. We are expecting more power and a happy combo overall with mote RPM.
As for a 2200lb car, I assume you mean without driver. Doing that WITH driver I cant see than happening at all..My RJ Stratus is a carbon body, carbon interior, carbon brakes, titanium housing, lightweight battery and cables, aluminum block, small radiator, etc etc etc. I spent a lot of time and money making sure it would be light. Minimum for TS is 2200 so I wanted to make sure we got there. With me in the care it is 2157 and I'm 250. So best of luck making 2200, I have had a few old school Mopars and could not get there. But use the approach we did maybe you can make it with every lightweight option available.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Best bore and stroke combo?
[Re: sgcuda]
#2395492
10/30/17 03:58 PM
10/30/17 03:58 PM
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Joined: Jan 2003
Posts: 13,530 Marion, South Carolina [><]
an8sec70cuda
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Why the "need" for 7500 rpm? You're gonna be heavier than 2200 and you'll need more than 875 hp to go 7.90s...even at 2200 lbs. The bigger the better...more cubes even w/ a head restriction will just move the power down lower. Like Al said, big bore makes power, the stroke and head flow will dictate where it makes it.
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 4 speed, Dana 60 '71 Demon 340, no drivetrain, on blocks behind the barn '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: Best bore and stroke combo?
[Re: sgcuda]
#2395723
10/30/17 09:41 PM
10/30/17 09:41 PM
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Joined: Jan 2005
Posts: 4,243 Charlotte, North Carolina
sgcuda
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I wanted 1,000 hp to make sure I'm solid into the 7's, but I don't know if I can do the B1MC deal the way I wanted to. I decided to lower my expectations and try to maximize I already have. If I can peak close to 900 @ 7,000 rpm, and catch a good air day, and lay off the cookies and potato chips, I might be able to squeak a 99 out of the old girl. As for the 7,500 rpm mark, a 7.90 will require a trap speed of 172+ mph, which, when coupled with a 4.10 gear and 32" tire, brings you in the area of 7,500 rpm.
[image][/image]
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Re: Best bore and stroke combo?
[Re: sgcuda]
#2395920
10/31/17 09:17 AM
10/31/17 09:17 AM
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Joined: Jan 2003
Posts: 13,530 Marion, South Carolina [><]
an8sec70cuda
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Don't build the motor around a gear ratio. Build what you can, then gear accordingly. You're making this build way more complicated than it has to be.
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 4 speed, Dana 60 '71 Demon 340, no drivetrain, on blocks behind the barn '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: Best bore and stroke combo?
[Re: Al_Alguire]
#2395929
10/31/17 09:35 AM
10/31/17 09:35 AM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
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Val-haul-ass... eventually
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... We have continually dropped the stroke in the heads up car and we make MORE power now with less stroke than we did before. For next year it will be same cubes at a shorter deck height. We are expecting more power and a happy combo overall with mote RPM. Sounds just like the evolution of NHRA Pro Stock engines.
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Re: Best bore and stroke combo?
[Re: sgcuda]
#2396311
10/31/17 09:00 PM
10/31/17 09:00 PM
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Joined: Oct 2007
Posts: 4,219 New York
polyspheric
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New York
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My personal taste: if you assume that head capacity is limited to some product of displacement (obtained by stroke change) X RPM, I'd rather use the longer stroke and keep the RPM down. Many $$$ worth of valve springs last another season, etc. The math: stroke length X +10% increases displacement by (duh) 10%. Increasing peak RPM by 10% gives the same product, but increases inertial load by 110^2, or +21%.
Boffin Emeritus
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Re: Best bore and stroke combo?
[Re: polyspheric]
#2396345
10/31/17 10:04 PM
10/31/17 10:04 PM
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Joined: Jan 2005
Posts: 4,243 Charlotte, North Carolina
sgcuda
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My personal taste: if you assume that head capacity is limited to some product of displacement (obtained by stroke change) X RPM, I'd rather use the longer stroke and keep the RPM down. Many $$$ worth of valve springs last another season, etc. The math: stroke length X +10% increases displacement by (duh) 10%. Increasing peak RPM by 10% gives the same product, but increases inertial load by 110^2, or +21%. Hmmm. Definitely food for thought. But is 7,500 rpm considered a lot of rpm by todays standards and technology? Are there beehive springs available yet for my application to keep valve train weight and inertia down? Any other weight saving ideas? For instance, my lifters look like they are solid steel. I have seen some that almost look tubular. Are there significant weight differences between lifter manufacturers?
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Re: Best bore and stroke combo?
[Re: rickseeman]
#2396704
11/01/17 02:18 PM
11/01/17 02:18 PM
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Joined: Jul 2010
Posts: 2,422 Pittsburgh PA
Eric
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Pittsburgh PA
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My Jerry Bickle Neon with carbon fiber body, carbon fiber rear brakes, MW drilled axles etc weighed 2200. It had a Ray Barton 572 (975 hp) and ran low 8's I think. (I only ran it in the 1/8 mile.) Normally 5.25 but a best of 5.15. Love that car!!!! My Arrow round tube mild steel with a BBM comes in at 2150#'s empty 2335# on the scales with me in it. 2200# on that Cuda may be tough.
5.53 @ 125 1/8th on the launch control..more left in her!
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Re: Best bore and stroke combo?
[Re: Eric]
#2402142
11/11/17 08:03 PM
11/11/17 08:03 PM
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Joined: Jan 2003
Posts: 9,944 Weddington, N.C.
Streetwize
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Weddington, N.C.
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Static displacement doesn't mean quite as much when you consider a 358" NASCAR motor is technically "bigger" at 9600 RPM than a 500" Bracket motor is at 6800 in terms of pumping capacity...assuming equal VE. After all the motor is an Air pump and (all else being equal) it's really the dynamic capacity that matters most, providing the gearing is optimized. With big motors the longer the stroke generally the shorter RPM band between peak torque and peak power and with a longer stroke (assuming the same head flow) the faster the power (rate of decline per 100 RPM) falls beyond peak power, that's mostly a function of the frictional losses of the increased piston speed/travel. Mopar wedges are relatively HP limited compared to say a BBC or Hemi not really due to port flow, but mainly because of the parallel valve placement causing the VE to fall. They do make a sh!t-Ton of torque through the middle though probably benefit from a longer (than BBC) rod/deck height) Wedges rely on a bigger bore as compared to a canted valve or Hemi so a a 4.50+ bore is a benefit. The sweet spot/balance for BBM wedges seems to be in that 550" 7500-7800 RPM range. I have a complete 366" 48 degree R block W2 Motor I would love to rebuild into a reliable Easy 900+ HP turbo project....If only I had a nice Race Ready door car to put it in. I was just at Darlington a few weekends ago drooling over my buddies 496" BBC nothin fancy home made 2700 pound 63 vette sporting 2 turbos clicking off easy 5.20's and 5.30's at 130 in the 1/8th....at less than 10psi of boost. Never lifted the hood the whole day into night of racing. Could easiliy go in the high 4's if he leaned on the combo a bit. https://www.youtube.com/watch?v=ACeZZ5dNJDQA legit and certified cage 2200-ish E body is VERY IMPRESSIVE no matter how you get it there.
Last edited by Streetwize; 11/11/17 08:18 PM.
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