wanna increase the rev limit. .. some points to ponder ov

[Captain Slarty]

here is a graph for the 172 f4r engine - valver and willy very similar.

this is G force against rpm.

the gforce is the force experienced by the piston, wrist pin and the crank pin..

these are HUGE loads.

between 1000 and 5000 rpm you have a fairly linear increase in load.. between 5000 and 7400 you double that .. AGH!!.. go above that.. and all I say is I hope you have some pretty bloody strong fasteners, pistons, crank etc..

Have fun.. and maybe reconsider if you want the rev limit upping..

Joe

http://homepage.ntlworld.com/captainslarty/pistongforce.jpg

 

[Captain Slarty]

Just a point.. the willy and valver will be the same type of non linear rise.. however, the stroke of the engine determines the max g load applied.

Joe..

 

[Eddd]

Thanks Joe,

Exponential is a nasty word...creeps into all sorts of things and usually seems to remind us of some sort o limitation or other. Damn...

Im going to experiment with the stock size tyres which may just make the gearing tall enough to sort out some of the awkward bits. It is currently sitting on 195/50 15s and I think the 185/55s are just that little bit taller.

Any recommendations for tyres? I need something of a compromise as I run it regardless of the weather.

Ed

 

[Captain Slarty]

HI Eddd m8.

Sorry, but tyres are not my forte really..

I personally like yokos.. I used the a008 for a few years on my tvr 350i..

bu, for a clio, I really am not the best person to ask

Joe.

 

[BenR]

mines running at 7500 rpm max, and i go there every now and then when the corner requires, but i dont go too far normal most of the time. But it does sound and feel ace.
ANyway, we are checking fuelling @ WOT on the RR and when the new cup exhaust comes, itll be changed to suit WOT.
Anyway, luckiy the air temp here is high, so its thinner......hopefully the 33deg ave. and 90% humidity will help....aiyee!
can i check for pre ig without taking off the head?.....like see if there have been any hot spots on teh plugs where they could cause pre ig?

 

[Captain Slarty]

Hi Ben, not really, The pre-ignition sources are all on the piston rim / flat top to squish area..,

re fuelling.. best is to check the fuelling on the rr with the gas analyser.. lama lights etc are pretty much useless due to the delay in response .. they give you a good feel for the mix, but not accurate enough.

Joe.

 

[Captain Slarty]

ben, again, even the rise from 7k to 7.5k is adding apx 300 positive g and 500 negative g - (piston push, piston pull)

pretty amazing increase...

Joe.

 

[BenR]

yea, ive been wathing it, but cant tell till were on the rollers again. its sounding fine right now....touch wood!

 

[GR7]

Hi there Ben, what are you up to tonight? Did you manage to get into the chat room?

 

[BenR]

nope, no chat room.....i cant get into tany chat room on any forum, always pops up as the most wanted thingy.

anyway, i went out and proceeded to drink till i woke up somewhere i didnt know....all fun.