bossman12r
Zone Head
Posts: 513
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posted November 10, 2006 06:32 AM
stroker?
What size stroker do you guys think works the best in a zx12 for drag racing in a non off set bore? I like the 1375 dont seam to last. Any thoughts.
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gen 4 zx10 is fast
  
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supra5677
Pro
Posts: 1279
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posted November 10, 2006 07:07 AM
go with a 3mm stroke..which will give you 58.4mm... you can still safely
rev your motor to 11625 and get the torque advantage. I believe your total
displacement will be 1347 with the 1270 pistons..
supra
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Y2KZX12R
Needs a job
CompetitionCNC.com
Posts: 3762
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posted November 10, 2006 10:24 AM
I'd go with the 1375. At 60mm the piston acceleration and MPS are well within the accepted limits. A 60mm stroke (1375) 12r can rev a lot higher than you think.
The bottom end isnt the concern. Its the valve springs.
I posted a thread about the piston acceleration and MPS a few weeks ago. At the 11,625 limiter kick in the 60mm stroke is still well within "safe" limits.
And a stock stroke 12r? Well, that puppy can rev like a 1000 if you like. Just change the cams. I dont know what the stock rod bolts are rated for (150,000 lbs?) but carillos would elimate any doubt. And when you start to loose ring seal because of a long gas path, you can gas port the pistons.
I've got over 3000 miles on my 1375 of very hard sunday AM rides running it usually between 6000 and 10,000 rpms the whole time. The only reason I dont bring it up to 11,600 is because its got stock cams and lower compression and its flat above 10,500 or so.
Theres no reason a stroker wont last as long as a stock engine if its built right. Yes you could have a flaw deep in the welded crank and never know it unless you xray the crank.
But its far more likely to fail if the assembler doesnt pay attention to ALL the details.
Its not just about bearing clearances and ring end gap.
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Y2KZX12R
CompetitionCNC.com
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supra5677
Pro
Posts: 1279
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posted November 10, 2006 10:37 AM
I agree y2 a stock 12r can safely rev to 126000 or even 13000. Heck even the stock
displacement 12s flatline at 10,000. Saw a built 1270 dyno at 205rwhp with over
size valves..peaked at 11600 still climbing
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bossman12r
Zone Head
Posts: 513
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posted November 10, 2006 07:22 PM
I have the extended rpm ecu mod and hd valve spring with 1mm ss exhaust valves and the intake on the exhaust side for the burned NOS gas to get out. What about the 1394 kit and do you think the knife rods are just as good as the A or H beam rods?
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gen 4 zx10 is fast
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GUNNER
Needs a life
Posts: 5778
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posted November 10, 2006 07:59 PM
Falicon rods suck.
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osti33
Needs a job
Posts: 2973
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posted November 10, 2006 08:32 PM
quote:
I have the extended rpm ecu mod and hd valve spring with 1mm ss exhaust valves and the intake on the exhaust side for the burned NOS gas to get out. What about the 1394 kit and do you think the knife rods are just as good as the A or H beam rods?
I am running stock rods in my stroker motor. I have never had a problem with them. If you are going to go aftermarket rods might as well get the best ones. I would go with the Carrillo H beams.
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osti33
Needs a job
Posts: 2973
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posted November 10, 2006 08:34 PM
quote:
What size stroker do you guys think works the best in a zx12 for drag racing in a non off set bore? I like the 1375 dont seam to last. Any thoughts.
This has been said before but I will say it again.
Stroker motors are 10% parts and 90% builder. The reason the don't last isn't because of the parts.
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Y2KZX12R
Needs a job
CompetitionCNC.com
Posts: 3762
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posted November 11, 2006 04:02 AM
quote:
Stroker motors are 10% parts and 90% builder. The reason the don't last isn't because of the parts.
+1
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Y2KZX12R
CompetitionCNC.com
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stef12rr
Expert Class
Posts: 144
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posted November 13, 2006 05:32 PM
i guys i want to know something about stroker when the say 4mm increase stroke that means they move the conecting rod bearing 4mm or 2mm off the center, and they will use a 2mm spacer base gasket
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