Thread: 4 tech strokers are coming !!!
07-12-2006, 04:36 PM #1
4 tech strokers are coming !!!
talked to falicon today and he shipped out a 4 mm stroker crank. i believe it was lawracing but i could be wrong. now that means we are going to see some serious fast skis out there and he told me it was not the only one.
07-12-2006, 04:42 PM #2
Thats awsome Bari, but remember strokers dont live well at high RPM's
07-13-2006, 03:46 AM #3
Can you elaborate on this please? Why don't they live as long, technically speaking?
07-13-2006, 07:05 AM #4
The stroke is too long and long stroked motors don't live well at high RPM's.
07-13-2006, 07:25 AM #5
- Join Date
- Feb 2006
increasing the stroke increases the distance the piston travels at any one RPM. Piston travel should be kept under 4000 feet per min. which is the threshold of reliablity.
07-13-2006, 11:21 AM #6
The design of the 4-tec engine allows for some serious "stroking" because the stock bore is much bigger than the stock stroke. The best design for an engine is one with a square stroke/bore. You could probably get 1800, maybe 2000cc out of the 4-tec 1500. The Kawi 1200 was stroked to 1500 (STX15F) and retained reliability. It would be nice to have a NA SD 4-Tec 2000cc that would blow the sponsons off a SC 1500 and not have the Achilies Heel clutch to ruin an otherwise great mill !!!
This is definitely in SD's future !!!!!!!
07-13-2006, 11:44 AM #7
Yea Rich, now that you mention it the stroke on these engines is extremely short.
Bari, any idea what Falicon is stroking them to?
07-13-2006, 12:42 PM #8
- Join Date
- Feb 2006
With the Rpms you guys want to run 8400rpm
the biggest you could go is a 70mm stroke
a 4mm stroked(67.4mm) 4tec at 8400rmp nets 3700fpm piston travel. Under the 4000fpm line.
a 100mm bore x 100mm stroke would be 5500 fpm and your engine life would be measured in operating min. not operating hours.
07-13-2006, 12:54 PM #9
JP, how about those of us that are running 8800-8900 RPM's?
07-13-2006, 01:03 PM #10
The stock bore and stroke now is 100 X 63.4 = 1494cc
A 4mm stroker crank would up it to 100 X 67.4 or 1588.3cc
A total gain of 94.3cc
The stock RXP makes .14390896921017402945113788487282 HP per cc
Multiply our newfound cc's and we theoretically get an additional 13.5706157965194109772423025543507 HP from solely a cc basis.
Sound about right in theory??
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