Posted April 13, 2007 - 08:16 AM
I am a college student, shopping for engines my school's FSAE team. FSAE is an international competition where students build and compete with their own formula style autocrosser. To get to the point, this year I am leading the engine team. Because of my previous knowledge with the WR/YZ line, I want to use one of these. It will most likely be highly modified (bored, stroked, ported, high compression, etc). My question is in regards to the transmission; I vaguely remember the WR having a wide ratio transmission, as opposed to the YZF's close ratio. Is this true/still true? If so, what years does that apply for? Also, if anyone knows the specs of the YFZ's tranny, that would be great.
Posted April 13, 2007 - 08:39 AM
Posted April 13, 2007 - 09:56 AM
just my 2 cents. good luck in whatever you decide!
if this is really the engine you choose, I think you found the right place!
Posted April 13, 2007 - 12:13 PM
I believe it is best for us. Previously, we used a Yamaha R6 motor. It was what we started with, and it stuck. However, we are forced to run a 20mm restrictor. That limits the R6 to around 70 horsepower, I believe. Our displacement limit is 610cc's. I came in, a new member this year, with a good amount of motocross experience. The four cylinder seemed inappropriate for a small race car. It is simply too heavy, in my opinion. I currently ride a YZ144, and previously owned a YZ265F. For the past couple years, teams have done well with single cylinder motors. With modification, and fuel injection, RMIT was getting 60 whp out of a WR450 last year. The weight reduction is around 65-70 pounds just out of the motor, not to mention the lighter drivetrain, smaller fuel tank, smaller overall frame, smaller exhaust, etc. The electrical system is also greatly simplified. The goal for this single cylinder car is something between 400-450 pounds. We are just starting organization for the 2007/2008 year, so if you guys have any suggestions, I am very open to them.
Posted April 13, 2007 - 03:00 PM
Only thing that's really gonna tie you, is if you bump-start the car, or need to run e-start. Then the choice is already made for you.
Posted April 14, 2007 - 03:26 AM
Posted April 14, 2007 - 06:18 AM
______________________07 YZ_________07 WR
Gear Ratio - 1st Gear 27/14 (1.929) 29/12 (2.417)
Gear Ratio - 2nd Gear 23/15 (1.533) 26/15 (1.733)
Gear Ratio - 3rd Gear 23/18 (1.278) 21/16 (1.313)
Gear Ratio - 4th Gear 24/22 (1.091) 21/20 (1.050)
Gear Ratio - 5th Gear 20/21 (0.952) 21/25 (0.840)