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Turbo CBR250RR track bike

86K views 230 replies 52 participants last post by  Aduro 
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#1 ·
Do you think that it would be quicker around the track or not?
 
G
#4 ·
Yes and No. Still same work to be done, but I do own it.

I was having a debate with a friend that said that turbo track bikes don't work. I agreed that a larger capacity turbo bike would be useless, but maybe the 250 might be the right mix that can be useful on the track.

Comments?
 
#5 ·
Worst case scenario it'll ride like a 125gp bike. Enough power to spit you off when it hits band if you're uninitiated.

What are we comparing it to though? A worked cbr250 tracky or a roadbike? The weight of the turbo could easily be offset with lightening efforts, there's a small increase in reciprocating mass but it'll still be easier to muscle around than a 600..

I'd say it'd be quicker, but can't say without riding one....
 
#6 ·
and I thought it was supposed to be a secret. :p

it will definetly ride different... you will always try to keep the boost on to have a good response on corner exits. it might be an idea to tune up an anti lag system.

but its getting more and more complex... you might as well convert it to efi to aloow tunability... otherwise its just going to be rough and not many options.
 
#7 ·
I thought you were trolling Rich :blush: Ok, the only reason I see it possibly being slower is if it has truly horrible lag. Even setup well it'll be harder to ride fast, but ridden well it should spank the NA.

Justin.
 
#9 ·
sir.b said:
I thought you were trolling Rich :blush: Ok, the only reason I see it possibly being slower is if it has truly horrible lag. Even setup well it'll be harder to ride fast, but ridden well it should spank the NA.

Justin.
And the weight thing, a 250GP bike corners faster than a motoGP bike don't forget.

It'll come down to whether or not the power offset will balance out the weight increase. Or fit better suspension.. but at that point you get dangerously close to having to ask yourself why bother with a cbr250 since there's so little cbr250 left!
 
#10 ·
-1 to the antilag, assuming stud would rather not be replacing his turbo well, probably at all, anti lag is probably not a good option.

i think it'll be just like any other new bike you wanna track, you'll need to get used to it and learn how to get the most out of it, but once all the bugs are sorted and your getting consistant lap times i think i'll be quicker, the extra acceleration and top end speed will outweigh the low end off boost riding i think.
 
#11 ·
richo said:
It'll come down to whether or not the power offset will balance out the weight increase. Or fit better suspension.. but at that point you get dangerously close to having to ask yourself why bother with a cbr250 since there's so little cbr250 left!
ofcourse it will... suspension will be the last thing to worry about. i doubt the change in cg would be significant enough to worry about.

if you ask that question... you may as well turbo an r1. then we are back at square one.

just tune it up... do some tests and mod some more :D there is alot that can be done.
 
#12 ·
Humbug said:
richo said:
It'll come down to whether or not the power offset will balance out the weight increase. Or fit better suspension.. but at that point you get dangerously close to having to ask yourself why bother with a cbr250 since there's so little cbr250 left!
ofcourse it will... suspension will be the last thing to worry about. i doubt the change in cg would be significant enough to worry about.

if you ask that question... you may as well turbo an r1. then we are back at square one.

just tune it up... do some tests and mod some more :D there is alot that can be done.
You're taking the piss aren't you? Please tell me you are!
 
#13 ·
crazylegs said:
-1 to the antilag, assuming stud would rather not be replacing his turbo well, probably at all, anti lag is probably not a good option.
then stud needs to make the desicion of what the life expectancy of this thing is going to be. i rekon the engine will lunch itself well befor the turbo is 1/10 through its life span. he needs to work out how much boost he wants also.

i think the purpose of the turbo mod is to max everything at the cost of everything else. so trying to make it reliable is kind of defeating the purpose.

its all up to stud at the end of the day.[hr]
richo said:
You're taking the piss aren't you? Please tell me you are!
rofl is all i will say

but in all seriousness... i think suspension should be sorted out after he works out what he is doing with the engine...

one problem at a time, yeah ;)
 
#14 ·
Humbug said:
rofl is all i will say

but in all seriousness... i think suspension should be sorted out after he works out what he is doing with the engine...

one problem at a time, yeah ;)
Clearly suspension is an afterthought in motorcycle design. Making maximum POWAH is all that matters. Clearly. Genius.
 
#15 ·
so tell me what suspension has to do with the turbo? the cg and total weight will change slightly acceleration characteristics will change... but to a lesser extent of a change of rider maybe.

i dont see how you can tune suspension to the bike before you put the turbo on... and at any rate... the turbo is already on... i wouldn't think he is going to remake the exhaust manifold to change cg etc etc?
 
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#18 ·
I'll be using the NSR 250 frint end from my N/A track if any one is interested. The plan is to have 2 CBR250 track bikes. One Turbo and one N/A just in case either one dies or I crash one.

I hate going to track days without a back plan if something happens.
 
#19 ·
ffs stop with the petty squabbling, this could be an interesting thread if you don't ruin it.

Brendan just said that it would be a good idea to sort out the engine before you sort out the suspension (which makes sense because you cant ride it without the engine running) and people jumped on it.

it's not like he was saying rip the front end off and replace it with two wooden sticks and a beach ball...
 
#20 ·
studricho said:
I'll be using the NSR 250 frint end from my N/A track if any one is interested. The plan is to have 2 CBR250 track bikes. One Turbo and one N/A just in case either one dies or I crash one.
Good to hear mate.

While I've got your attention.. I was in Ringwood yamaha on the weekend and look what I spied....



I can't understand why you'd want to ride a fast bike with nugz suspension. The NSR front should compliment it nicely.
 
#21 ·
BL: Brendan spent over 9000 grand on his CBR without touching the suspension, so there's history behind the comments.

Justin.
 
#22 ·
sir.b said:
BL: Brendan spent over 9000 grand on his CBR without touching the suspension, so there's history behind the comments.

Justin.
Meh, what would I know about suspension anyway. :I

I'll STFU now and let stud do his thang!

Keep us posted :)
 
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#23 ·
Nice find Richo with the RZ500. How much did they have on it?

Getting back to topic. I don't have the time, room or funds at the moment to play with this, but I nearly did the other day.

I had to control myself. I do have a brand new spare turbo now that I bought in case this one blows up.
 
#24 ·
richo said:
sir.b said:
I thought you were trolling Rich :blush: Ok, the only reason I see it possibly being slower is if it has truly horrible lag. Even setup well it'll be harder to ride fast, but ridden well it should spank the NA.

Justin.
And the weight thing, a 250GP bike corners faster than a motoGP bike don't forget.

It'll come down to whether or not the power offset will balance out the weight increase. Or fit better suspension.. but at that point you get dangerously close to having to ask yourself why bother with a cbr250 since there's so little cbr250 left!
Two things;

The smaller GP bikes don't corner faster because they can they corner faster because the ideal line changes depending on the amount of power you've got.

The second is that you're talking about mid corner speed, not point to point speed.

EDIT: Nearly forgot, I can't really see how even a turbo with a bit of lag in it would really hurt track times, its not like the CBR250 has got enough poke to highside exept in the sillyest conditions (ie full lean wet track low speed corner). so in that circumstance then more power = more performance.
 
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