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BEC top speed? In order to work out gear ratio
woodsy144 - 27/11/19 at 12:51 PM

Hello, I'm am now trying to figure out final drive. Being chain driven I can pick and choose. Build a sprocket to suit
What works well for a R1 powered car?
If you know the stop speed, I can work back to match.
Any help would be great.
I was current thinking of about 210km/h.
Note thing must be drivable in traffic.


BenB - 27/11/19 at 02:01 PM

Presumably it depends on the aerodynamics of the car. I would imagine most Locost style cars hit an aerodynamic brick wall well before 130mph.


ian locostzx9rc2 - 27/11/19 at 05:29 PM

130 mph would be about right I had a striker with a Kawasaki zx9r it was geared to be flat out at 124mph never had an issue getting there wasn’t the lightest striker and it had a full windscreen .

[Edited on 27/11/19 by ian locostzx9rc2]


snapper - 27/11/19 at 06:14 PM

What bhp is the r1 engine?
I was told by Andy Bates that a 7 would do about 110 to 115mph but a full body car like a Fury would do near 130 with the same setup


SPYDER - 27/11/19 at 06:32 PM

This BEC gear calculator might be useful...





CLICK HERE



Or Google "BEC GEAR CALCULATOR" Lots available.


Kev99 - 27/11/19 at 06:35 PM

Mk Indy 2008 R1 4c8 engine, About 125 mph top speed
Quick up to 115 mph then starts to takes a little more time as u would expect, 3:62 diff 13 in wheels hope this info helps

Kev......


Jon Ison - 27/11/19 at 07:26 PM

Hit limiter in top around 142/3 gps.


procomp - 27/11/19 at 09:12 PM

As Jon says. If its a pure track car The RGB rear engine cars ( AERO ) hit 145mph, the front engine cars hit 135mph using 1000cc
If road and occasional trackday, gear for 125 mph youll be fine.

Cheers Matt


woodsy144 - 27/11/19 at 10:01 PM

Thanks guys, i will target 125mph


TimC - 28/11/19 at 11:21 PM

quote:
Originally posted by Kev99
Mk Indy 2008 R1 4c8 engine, About 125 mph top speed
Quick up to 115 mph then starts to takes a little more time as u would expect, 3:62 diff 13 in wheels hope this info helps

Kev......


That is so interesting. Full body is worth 10mph then.


steve m - 29/11/19 at 09:06 AM

I was under the impression that some more questions would be needed, like
what is the car going to be used for ?
as if its a track only car, top end speed is a requirement,
but a road only car, top end is worth nothing, as acceleration is needed more

You cant have top end speed and acceleration using just one setup

I will also agree that any 7 style of car will feel like a brick at a certain speed,
My deceased 7<< hit that wall at about 100, it was just like having the brakes dragging above that

steve