CBR250R key dimensions

[waz91]

Hello Everyone,

We are switching to a new set up running the 1 cyl cbr250r in the future, but currently do not have one in our possession. This is making packaging with any degree of confidence a little tough.

If anyone has any of the following data they would be willing to share it would be a big help in moving things along until we procure an engine:

1- A CAD model
or
2- rough extreme dimensions and location of mounts (+/- 10mm should suffice)

Rob
Chassis and Suspension
Waterloo Hybrid

[JSR]

Can't really help you out, but have you considered the crf250 engine?

Here is a cad model for the crf-engine: https://grabcad.com/library/crf250x-honda-engine
Note that there is quite a big difference in the cylinder "tilt angle" but I would guess that the lower mounting points doesn't differ too much.

[Mbirt]

I know this doesn't help you find CAD, but here's my take on Hybrid:

If I remember correctly, FSAE Hybrid is the only FSAE competition where the fuel economy doesn't matter--just use every drop of the allotted fuel volume. You're free to use the heavier, lower-power CBR250R engine, but it will never make the power that a state-of-the-art motocross 250 can within the "stock" FSAE Hybrid rules that mean you don't have to run a restrictor. I would be consulting 250cc MX engine builders to see which engine can make the most power with a stock cylinder head and piston (the only two things the "stock" engine rules take off the table). With maximum-effort camshaft design and intake and exhaust tuning (take advantage of that delicious 110 dBA noise limit while it lasts), you should find yourself in the 40-45 hp range. Supplement this with the simplest, lightest low-voltage electric drivetrain to only complete the EV accel event in 10 seconds, and you've got yourself a powertrain capable of winning the competition with minimized (controls, electronics) design effort, risk, and weight.

IC1.2 Permitted modifications to a stock engine are:
(a) Modification or removal of the clutch, primary drive and/or transmission.
(b) Changes to fuel mixture, ignition or cam timings.
(c) Replacement of camshaft. (Any lobe profile may be used.)
(d) Replacement or modification of any exhaust system component.
(e) Replacement or modification of any intake system component; i.e., components upstream of
(but NOT including) the cylinder head. The addition of forced induction will move the engine
into the modified category.
(f) Modifications to the engine casings. (This does not include the cylinders or cylinder head.
(g) Replacement or modification of crankshafts for the purpose of simplifying mechanical
connections. (Stroke must remain stock.)

[Mbirt]

I'll admit that most of my knowledge of the ins-and-outs of Hybrid comes from Cole and his era-dominating teammates at A&M.

It seems that teams take the "Hybrid" part of the competition name too seriously instead of looking at the points structure and really analyzing the points available per amount of hybridization--just like how Clean Snowmobile teams were throwing their resources at stoichiometric operation without looking at the points structure and proving that the concept actually has more potential than other types of combustion/aftertreatment.

[mech5496]

Took a quick look at the rules and could not find anything on max. electric power. I assume there is a limit but somehow I missed it, is that so?

[waz91]

I see this kind of opened a can of worms, but while we are here haha:

I feel that having the 2 drive systems creates many different paths to reach the final goal, probably more so than our pure gas/electric brothers. We did look at CRF as part of our concepts but the CBR won out. when I first found the CRF on grabcad it really got my hopes up the CBR was on there.

In the future I think we will be definitely looking at the lightweight IC dominated route as a potential option. I think ETS has done a good job proving you can make more than enough power out of a 250 lol. However I don't feel basing our lvl 3 points strategy around a reliable well tuned motor dominated hybrid given our lvl 4 resources would yield us our best overall placing, for this chassis at least.

Electrical power is rule limited via max system voltage and accumulator stored energy, No specific HP output limit on the EM

Not sure why but it always seems to rain at the hybrid events haha. I have done it once, and driving in the rain with a lot of electrical energy around you requires a certain level of confidence in your electrical guys lol