Pinned So what have you done to your bike today?

A Canadian Eh!

Mate, How is it that you know so much about turbos and motorcycle engines? Have you done this before? I see large capacity motorcycles running turbos all the time (at the drags), but never anything smaller than 900cc.

I have a 1990 ZXR250 drag bike that I'm slowly getting ready for action. In Australia, there are basically 2 classes I can run in, D/SB and D/MB. The "D" is for normally-aspirated bikes up to 600cc and the "SB" is for Street Bike (little modes allowed) and the "MB" is for Modified Bike (more modes allowed, wheelie bars etc) . I'll be lucky to get my bike to run 12's which is about 2.5-3.0 seconds off the D/SB record (no joke, some guy runs mid to high-nines on a ZX6R!). There is a class (DD/MB) that lets you run forced induction up to 600cc and the record for that class isn't too bad. I think a twin turbo 250cc might give it a good shake. I was thinking of supercharging, but you need something for the supercharger to spin off and my engine spins faster than most superchargers (20,000rpm). Nitrous might be okay, but I think turbos might too. Better still...both. The problem with any forced induction (as I'm sure you know) is that things can and often do go Boom. Especially if you don't know what you're doing.

I will keep watching your thread and see how you progress. FYI, 2-strokes are banned from all of these classes and I have a personal ambition to see how quick a 4-stroke 250cc can get down the quarter mile (before I move onto something faster).

Cheers

Frank

 

Thanks Aky. Found the thread and will read it tonight. Funny website CBR250.com; Good info mixed with people slagging off at each with bountiful use of colourful language...I'm pretty sure Kiffsta and the other site admins would like this site getting that out of control.

 

Hey Frank, I just looked up the ANDRA 2014 book and Mod Bike you are allowed to run any engine type (or multiple engines Max of three motorcycle engines with NO capacity limit) up to 2500cc, any modifications permitted, turbo, supercharging and nitrous oxide permitted.
Street bike will NOT allow two strokes, they have to run MB. This came about (I have been told by head office) because a bloke in SA was running an outboard two stroke engine and blitzing the field. This I think may have been a Swiss engine from a sidecar outfit.

 

Thanks Murdo,

MB (Modified Bike) classes are A to D and AA to DD. The only class I can run a 250cc (4-cyl) bike in is D/MB or DD/MB. I'm starting off in D/SB and then moving to either D/MB or DD/MB depending on my research into Supercharging/Turbocharging a 250cc engine. Seems like a few folks have supercharged and/or turbocharged small capacity 4-strokes, so might be a goer eventually. In the early day, there was a guy in the UK (Mick Hand) that ran small capacity 2-strokes with superchargers and (I think) Turbochargers. He ran pretty quick (9 sec or maybe quicker). Running AA/MB is not on my things to do list. If I want to give myself a good scare I can check how much I still owe on my mortgage!

 

You're right about superchargers using power. The trick is get the right sized supercharger for the job you want to do and spin it faster or slower depending on your requirements. I prefer supercharging for drag racing; it's instant power and you don't have to rev the crap out of the engine to bring the boost up. Using the old GMC supercharger codes (6-71, 8-71), a 250cc engine would probably get heaps of boost from a 1-71 blower. I'm looking at a small unit (SR1040) that weighs about 4kg (http://www.hi-flow.com/HP002dSuper.html). What supercharger did you run on your 175cc motor?

 

Do you mean "migrated from Canada"?

 

One word - Rotrex

 

Thanks Mael. Seems like there are a few options around the place.