SOHC rev limits
 

i have a y7 head that im thinking of using along with a bisi cam.

how high do you think its safe with stock springs/retainers ? 7500k ? stock is like 6600k on the y7. :-\


are z6 springs any better ? i have a whole head thats fucked but with good springs/retainers.

Re: SOHC rev limits
 

Don't use a almotor cam in a turbo motor. I seen people push more then that on stock y7 head.

Re: SOHC rev limits
 

All motor cams are good for boost.

Re: SOHC rev limits
 

Ahh no there really not, they blead off boost. Bisi knows his stuff, if you call him up he will make a cam for your setup.

Re: SOHC rev limits
 

REALLY? ENLIGHTEN ME!
Show me any proof and don't type me a essay about why you think they suck.

Re: SOHC rev limits
 

i talked with bisi and he said he will make the cam fit my setup. and ill just take his word on that.

cam isnt really the issue here, its the springs.


are the z6 springs worth swapping ? (time and effort)

Re: SOHC rev limits
 

If you talked to bisi, why didn't you ask him about the springs?

Re: SOHC rev limits
 

This is what bisi him self told me when I call for a cam. The motor that it was going into was a y8 with a 16g and a na cam. Boost would take for ever to come in and would just die off. Bisi said the cam was bleading off the boost.

Re: SOHC rev limits
 

Honestly if you're going to go through the trouble and the immensely large sum of money that it costs to have Bisi himself design you a cam, why would you not in all honesty want to upgrade your valves and springs/retainers? And FWIW, z6 springs are a different length than most other D-series springs I've seen (except for maybe a y8), so you would almost want to assume them being longer than the y7's as well. Upgrade everything else, and if you can't find the parts to do so, then you might want to consider a change in head design. :P

Re: SOHC rev limits
 

those heads wont really flow much over ~ 7k w/o extensive port work and properly tuned intake manifold and exhaust system


SOHC allmotor cams suck for boost BECAUSE 2 resons


1 all motor cams have alot of OVERLAP, aka when the intake valve and exhaust valve are open at the same time, helping scavange excess exhaust gasses due to the vacume created after every exhuast pulse, wich also pulls in extra intake gasses, causing the whole intake charge to pass through the combustion chamber


2 SOHCs have no adjustability in the overlap, DOHC arnt as bad, because you can dial out the overlap with adjustable cam gears. therefore you have a large lift and duration with less than recommended overlap, POSSIBLY produceing more hp, but not necessiarly.




sean