Re: Andy, your 470/270TF indy 440-3 results
[Re: CSK]
#2716238
11/15/19 10:09 PM
11/15/19 10:09 PM
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Joined: Jan 2007
Posts: 8,031 Mt Morris Michigan
mopar dave
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Mt Morris Michigan
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An engine produces peak torque at the rpm where it is most efficient. Efficiency is the result of many factors, including airflow, combustion, and parasitic losses such as friction and windage. Comparing two engines with the same displacement, a long-stroke/small-bore combination is simply less efficient than a short-stroke/big-bore combination on several counts. Big bores promote better breathing. If you compare cylinder head airflow on a small-bore test fixture and on a large-bore fixture, the bigger bore will almost invariably improve airflow due to less valve shrouding. If the goal is maximum performance, the larger bore diameter allows the installation of larger valves, which further improve power. A short crankshaft stroke reduces parasitic losses. Ring drag is the major source of internal friction. With a shorter stroke, the pistons don’t travel as far with every revolution. The crankshaft assembly also rotates in a smaller arc so the windage is reduced. In a wet-sump engine, a shorter stroke also cuts down on oil pressure problems caused by windage and oil aeration. BINGO!
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Re: Andy, your 470/270TF indy 440-3 results
[Re: Cab_Burge]
#2716311
11/16/19 09:54 AM
11/16/19 09:54 AM
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Joined: Jan 2007
Posts: 8,031 Mt Morris Michigan
mopar dave
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cab, what were the results of the 558? From what I understand 20% of your power force is used up right after TDC firing, so what is better, a short stroke with each cylinder firing closer together or a longer stroke firing further apart with fading energy on the longer down stroke, but with a little more energy at TDC than the short stroke? I don't know, but this stuff is very interesting to me and I would sure like to know. To me , the longer strokes are fine as long as you can get a long rod in there. There are plenty of engine builders building long stroke motors that work and that's fine buy me. I have no issue with it. I still think for me personally, a 470 is a design of my better liking. I said this before, the Japanese build some pretty bad ass inline 4's. I had a couple. The last one was an 08 gsxr750 that I did a little super tune on. It made 140hp to the rear wheel and was almost scary to ride. 48.7mm stroke, not sure what that is in inches, but its very short, under 2". I understand torque moves the object and maybe the name of the game, but there are other things that come into play that pull it down a bit imo. no disrespect here to anyone, just try to learn.
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Re: Andy, your 470/270TF indy 440-3 results
[Re: mopar dave]
#2716319
11/16/19 10:33 AM
11/16/19 10:33 AM
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Joined: Jan 2003
Posts: 14,492 So. Burlington, Vt.
fast68plymouth
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I Live Here
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a long-stroke/small-bore combination is simply less efficient than a short-stroke/big-bore combination on several counts Huh. And yet the highly successful Ford coyote 5.0 is 3.63 bore with a 3.65 stroke....... while the old school 5.0 is a 4.00 bore and a 3.00 stroke. You go for the 470....... I’ll take the 511. 41 extra cubes for zero extra dollars and zero extra effort is a win win in my book.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Andy, your 470/270TF indy 440-3 results
[Re: mopar dave]
#2716404
11/16/19 02:16 PM
11/16/19 02:16 PM
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Joined: Mar 2018
Posts: 114 NW Indiana
powertrip
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I dont know about faster, but wouldn't surprise me if the 470 out accelerated the 511. Maybe a better 60 or 1/8. It would surprise the heck out of me. I've seen quite the opposite, everything else being the same.
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Re: Andy, your 470/270TF indy 440-3 results
[Re: mopar dave]
#2716407
11/16/19 02:25 PM
11/16/19 02:25 PM
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Joined: Mar 2018
Posts: 114 NW Indiana
powertrip
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Big bores promote better breathing. If you compare cylinder head airflow on a small-bore test fixture and on a large-bore fixture, the bigger bore will almost invariably improve airflow due to less valve shrouding.
I am sure this is true on the better breathing heads, but on heavily worked RPM's there was zero difference in flow between a 4.350" and 4.500" bore on my flow bench. I haven't tested any Victors, though.
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Re: Andy, your 470/270TF indy 440-3 results
[Re: mopar dave]
#2716409
11/16/19 02:34 PM
11/16/19 02:34 PM
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Joined: Mar 2018
Posts: 114 NW Indiana
powertrip
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I said this before, the Japanese build some pretty bad ass inline 4's. I had a couple. The last one was an 08 gsxr750 that I did a little super tune on. It made 140hp to the rear wheel and was almost scary to ride. 48.7mm stroke, not sure what that is in inches, but its very short, under 2". I understand torque moves the object and maybe the name of the game, but there are other things that come into play that pull it down a bit imo. no disrespect here to anyone, just try to learn. I still love my Japanese inline fours, built quite a few. You do know that they sold stroker cranks for Gixer's ( and others ) and it made them faster?
Last edited by powertrip; 11/16/19 02:35 PM.
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Re: Andy, your 470/270TF indy 440-3 results
[Re: mopar dave]
#2716412
11/16/19 02:40 PM
11/16/19 02:40 PM
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Joined: Mar 2018
Posts: 114 NW Indiana
powertrip
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the next motor will be a short stroke big bore motor. Short stroke big bore motors run great!! The only thing that beats them ( in Torque, HP, and ET ) are long stroke big bore motors.
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Re: Andy, your 470/270TF indy 440-3 results
[Re: mopar dave]
#2716449
11/16/19 04:01 PM
11/16/19 04:01 PM
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Joined: Mar 2018
Posts: 114 NW Indiana
powertrip
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I had no idea. I was happy with the way they came from the factory other than slip on's and power commanders. Yes, they were impressive mildly modified. But you could go stupid fast with silly money.
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Re: Andy, your 470/270TF indy 440-3 results
[Re: mopar dave]
#2716453
11/16/19 04:07 PM
11/16/19 04:07 PM
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Joined: Mar 2018
Posts: 114 NW Indiana
powertrip
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I agree. There's just something about the 511/512 that doesn't do much for me. 470 or even the 528 looks good with 4.150x4.500 bore. Don't get me wrong about my 511 thou, it runs good and i'll get it figured out, just don't think it's the best mechanical design with 6.535 rods. To be honest, I prefer RB's with a 4.25" or longer stroke (damn rod angles). But I wouldn't kick a 511 low deck to the curb if I had one, they run great.
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Re: Andy, your 470/270TF indy 440-3 results
[Re: powertrip]
#2716459
11/16/19 04:26 PM
11/16/19 04:26 PM
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Joined: Jan 2003
Posts: 14,492 So. Burlington, Vt.
fast68plymouth
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There was a low deck 526(4.375 x 4.375) here for freshining a couple years ago. Original Koffels combo, bowl ported B1 heads(384/262@.750)....... made about 830hp. IIRC, that used 6.700 rods.
Came out of a mud truck.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Andy, your 470/270TF indy 440-3 results
[Re: mopar dave]
#2716494
11/16/19 06:13 PM
11/16/19 06:13 PM
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Joined: May 2003
Posts: 6,560 Downtown Roebuck Ont
Twostick
Still wishing...
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Still wishing...
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wow, same rod/stroke ratio as my 511. Looks like it made some real steam. Nice Same rod ratio as a BBC. They seem to get down the track OK. Hemi Fred once told me the only purpose the rod length serves is to put the piston where you want it in the bore. This was in reference to that turbo engine he built. He got a bunch of new blower pistons from a TAD friend of his for almost nothing and built the engine around them and I think an old fuel crank and whatever length aluminum rod put the piston where he wanted it. I think he said he had $2500 total tied up in parts and machine work. Kevin
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Re: Andy, your 470/270TF indy 440-3 results
[Re: mopar dave]
#2716539
11/16/19 08:37 PM
11/16/19 08:37 PM
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Joined: Jan 2003
Posts: 14,492 So. Burlington, Vt.
fast68plymouth
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I Live Here
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Shafiroff does a 582 BBC with a 4.375 stroke and 6.535 rod......... 1.49 RR. 990hp@7200.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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