How much overdrive is max with a Kobelco

OK - the question is can a Kobelco K-9 Superman go 1.70 (70%) overdrive and make horsepower. 526 Hemi veney heads w/ 2.500 intake valve, R296 Cam the usual rest of motor. An ADRL race is coming close by and curious if a roots blower can possibly even qualify. Will need 14MM Gt pulleys if this is a reality - ok experts - help is requested - anybody tried it? Thanks Wayne R

 

I have been told that 12500-13000 max rotor speed. So i ask 70% over what crank shaft rpm hope it helps

 

Why not call Darren at DMPE and ask him .

 

Generally speaking I limit rpm to a max of 9200 but I have gone as low as 8300 - depends on the tracks - I will call DMPE - but I'd sure like to hear from anyone who has tried it - or has been closer to that 70 number I have run 38 over - which is where I am now and it makes good power - but the ADRL Pro Mod guys are making astounding runs. Just figured there might be some AFC guys in here that used to run the roots that high.
At 9200 x 1.7 = 15,640 RPM
At 8300 x 1.7 = 14,140
Pretty far from that 12500 range
Wayne R

 

we ran our roots @ 56 over a lot but never much more than that
i think that you will heat the air more than you might gain over that
but i have heard of people going as high as 65 over years ago i just never have went that high myself

 

Any of the ADRL guys running a roots blower have a 16-18/71 with the exception of Ed Hoover who has qualified with a legal 14/71 combo . The std. is a PSI C rotor over there . Let us know what Darren tells you also . One thing you did not mention is the length of the top opening which may play a roll in how fast you should spin the blower .

 

70 over

call Jon @ DMPE in New York. He will help you out, and tell you what you can and can't do. Office # 1-716-832-7583/ e-mail JonSalemi@hotmail.com/ Don

 

Jon says 34 - 38 max without more mods and the m-5 only to 44-50 max - I guess I won't try 70. To bad several sanction bodies allow OD that you can't possibly use - thanks guys for the help - wayne R