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Knife edged crank?



  172 Cup & Clio dci Van
Any one know of one for the clio or has any one had a custom made knife edge crank for their clio?

If yes where from how much etc etc?
any idea on 'actual' gains?

I am building up an NA tuned engine hoping to reach approx 240bhp
i have all the forged internal higher compression pistons etc etc etc

Just not seen anything about knife edged cranks hence my thread.


Please stay on topic
i.e dont start telling me advanced lessons are better lol, i have had some. (you get my point)



Cheers
 
Knife-edging is a process that a machine shop will do to a crank that will basically remove a lot of material from the crank counterweights, which are the large cast portions of the crank that connect the main bearing journals to the rod bearing journals. The machinist will remove the material at an angle and the result looks similar to a knife's edge, hence the term. The overall result is the crank has less weight, so it will spin faster easier (but also lose revs faster) and the 'knife-edge' will also cut through the air and oil easier, in effect reducing the parasitic drag from these variables. This is a old-school racer technique and it works, but the overall gain of this is realively small, its mostly to help the engine rev faster and there are other mods that are necessary to use the gains from this mod: lighter flywheel, cams, higher rev limiter.
 
  ITB'd MK1
I wouldn't bother personally, most places that offer it as a service dont know how to do it to give a real gain. A straight cut edge wont really help that much, you need a profiled shape.

A full close tollerence balance will give the biggst gains (and really makes a difference to the F4R)
 

K-Tec Racing

ClioSport Trader
  172LBT-172HBT-197-R2
A world 1st, Dan and Fred agree on something...

I have to agree, on a TOP engine it may be worth it, but I certainly havn't bothered on any of my engines for myself.

A decent balance as the guys said is far better, removing weight from the flywheel is as advantageous really in this instance.

Andy
 
  BMW M5 & E36
Is much to be gained from lightening/balancing the flywheel alone, or would you not generally bother unless it was with the crank too?
 
  Lionel Richie
i've found it does help the engine rev cleaner/quicker, as a mod on its own its a hell of a lot of work JUST for that, if its in bits though, why not!
 
  172 Cup & Clio dci Van
standard balanced item will be fine (get the entire bottom end done)

Could you recommend anywhere for me Fred?

I wouldn't bother personally, most places that offer it as a service dont know how to do it to give a real gain. A straight cut edge wont really help that much, you need a profiled shape.

A full close tollerence balance will give the biggst gains (and really makes a difference to the F4R)

Could you recommend anywhere Dan?

A world 1st, Dan and Fred agree on something...

I have to agree, on a TOP engine it may be worth it, but I certainly havn't bothered on any of my engines for myself.

A decent balance as the guys said is far better, removing weight from the flywheel is as advantageous really in this instance.

Andy
I have got a lightend & balanced flywheel ready to go in, along with cams itbs pistons uprated clutch etc etc
I want to put something a bit special together N/A wise.

Andy i expect i will be in touch r.e mapping at some point mate.





All- what sort of costs do you think i would be looking at for fully balanced ?

and what sort of cost would be typical for having a crank knife edged?
even if there are very minimal gains i would still like to have it done so that i can have that tiny tiny bit more :rolleyes:



Would it be a good idea for uprating the rods for forged ones? or not req as much with NA power?
i wasnt going too...
 
  BMW M5 & E36
i've found it does help the engine rev cleaner/quicker, as a mod on its own its a hell of a lot of work JUST for that, if its in bits though, why not!

That's what I was thinking. Engine will be coming out as part of a winter overhaul anyway. How much would you expect to pay for the flywheel work?
 
  172 Cup & Clio dci Van
So currently NO one has a knife edged crank on a f4r?

I am guessing there may well be a reason for this but if it hasnt been done how do you know if it is not very beneficial? apolagies if i am being naive, but surely there must be weight that can be lost of the crank and that lost weight is - a gain in performance due to less rotational bla bla etc

Think i will probably get one done even if the gains are microscopic :cool:
 
  ITB'd MK1
knife edging, i dont have anyone to recommend, balancing I can arrange (though you're down south IIRC) not revealing my trade sources though ;)
 
  172 Cup & Clio dci Van
knife edging, i dont have anyone to recommend, balancing I can arrange (though you're down south IIRC) not revealing my trade sources though ;)

send me some contacts/costs danny!

i can jump in me clio dci van that does precisely 1,007 mpg and ddrive up to drop off the engine
assuming prices are good.

I have also emailed Fred's contact after looking through their website they look pretty top boy.

cheers
 
  Lionel Richie
the chap i know (he ran ALL renaultsport engines for the uk, ie you had a clio cup or a formula renault, he looked after the motor) he says "no"

that do you?
 
  172 Cup & Clio dci Van
so he knows renaults then


when you said he says no do you mean
no dont bother
no he cant help or no he pretends he didnt look after the renault cup and formula renault engines?
lol

cheers
 
  Lionel Richie
don't bother in other words!

he did look after the engines for R-sport, why do you think i've got a load of spares knocking about! anyone need a dry sump kit? ;)
 
  172 Cup & Clio dci Van
what about balancing fred? dont bother with that either?

dry sump kit costs?

open to anything mate! i want to have a top boy N/a engine.

cheers
 
  Lionel Richie
yeah get the entire rotating bottom end assembly checked/balanced (pulley, crank, rods, flywheel etc)

what you wanting? 240bhp?
 
  172 Cup & Clio dci Van
240bhp is my aim ye

do i need forged rods ? wasnt planning on getting any guessing i dont it they can do supercharger on stock internals to 250/60bhp right?
 
  Lionel Richie
rods in my experience are fine for 8k rpm (as long as you use ARP's)

some of the "uprated" rods are tat made in taiwan and worse than oe
 
  ITB'd MK1
they're ALL made in the same factory i recon. there's no difference between any of them at all. They're always all perfectly weight matched and end/end balanced which is better than oe ;)
 
  172 Cup & Clio dci Van
Right not going to go with the uprated rods, i dont think they are required.
was thinking 7500rpm ish nothing like 8k


what we think a dry sump kit would cost?
i am going to go do a bit of research on dry sump kits as my knowledge of them is patchy
 
  Lionel Richie
you don't need to go above 7500pm with the right cams

dry sump is nice, but not really needed!

what spec you planning?
 
  ITB'd MK1
Right not going to go with the uprated rods, i dont think they are required.
was thinking 7500rpm ish nothing like 8k

you wont do top power if you stick under 7500. depening on cams you'll likely find the power is still rising at the limiter if you do that. Uploading a graph now....
 
  ITB'd MK1
Nigelroles240bhp.jpg


ignore the title on the graph, it's not the turbo car
 
  172 Cup & Clio dci Van
well it would be the 421 cams i would be using i expect, bit more mainstream than the hillpower ones...i got the hillpowers 2nd hand and cheap... just thought fcuk it that will do for a bit more power for the time being...(ages ago)
 


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