Briggs @ Straton on Nitrous
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used to have a jr dragster than used a B&S 5hp block. one put out about 13hp and the other maybe 20 or so hp. the "big" motor ran a second and a half quicker in the 1/8th. it would have been fun to put that on nitrous. mine didnt put out anywhere near as much power as some of them. some put out upwards of 40 - 50 hp maybe more. they ran high 7's in the 1/8 mile at 400 lbs.
i had heard of jrs in california that were using nitromethane. they also make superchargers for the B&S engine. but i think they have to be a horizontal shaft.
i cant believe how long that power lasted.
[ March 22, 2006, 10:07 PM: Message edited by: racer12306 ]
i had heard of jrs in california that were using nitromethane. they also make superchargers for the B&S engine. but i think they have to be a horizontal shaft.
i cant believe how long that power lasted.
[ March 22, 2006, 10:07 PM: Message edited by: racer12306 ]
I am in the market for a push mower, did anyone catch the brand of that mower???
Not much brainpower there. Evidently they have never hear of aluminum flywheels self destructing into a thousand pieces.
Exactly what I was thinking!
"Boardum"
That's one tough little mower. I think it's a Techumsa (sp) motor. I have a mower that looks just about like that one.
I thought I was going to see a riding mower. Whats the point of doing this with a push mower? Anything over 1800 rpm or so and the blade would shatter? Seems like preignition is what stopped it all those times from halfway until the end of the video, combustion happening too fast and the backfiring robbing it of air.
An aluminum flywheel at those RPM's is an instant grenade. Years ago at a WKA kart race a bystander was killed by an exploding flywheel.
What you are seeing there is valve float. The valve springs are not intended for those kind of RPM's.
What you are seeing there is valve float. The valve springs are not intended for those kind of RPM's.
that engine probably only made it to 5500 rpm's because of valve float. thats kind of a safe guard on lawnmowers. they design them with really weak valve springs to that incase of a stuck throttle the engine wont over rev and blow the flywheel apart. it just floats the valves.
on racing gocarts and such they do replace the valve springs with stiffer ones so they can rev alot higher.
notice that they were spraying WAY too much nitrous into that thing. there was so much overspray it was just flowing out the nitrous jet and onto the ground. they probably used the smallest jet they could buy, but even the smallest automotive jet is way too big for a lawnmower.
ill give em an a for effort though. it was pretty cool.
on racing gocarts and such they do replace the valve springs with stiffer ones so they can rev alot higher.
notice that they were spraying WAY too much nitrous into that thing. there was so much overspray it was just flowing out the nitrous jet and onto the ground. they probably used the smallest jet they could buy, but even the smallest automotive jet is way too big for a lawnmower.
ill give em an a for effort though. it was pretty cool.
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