4k Vs 5k Dispute

[agius]

imagine the amount of noise a glimer drive hooked on to a sc14 blower on a rolla would make ;)

[brendan]

yeah true

 

if it allows for the stock fan it'll be great?

love the sound of the old gilmers!

[KENut]

Give your sarcasm meter a knock, I think it's on the blink.

 

Hahaha true, I've replaced it with a working one today to replace the overclocked old one. Cheers ;)

phew, I was a bit worried philbey had lost it, but all good

[coln72]

Back on topic.

 

My KE20 - 5k, twin asains, cam, extractors and exhaust

The old mans KE20 - 4k, std carb, BIG cam, extractors, exhaust and higher comp.

 

Both ran locked 4.2:1 diffs and 13" rims with similar tyres. Mine was lightened more than the old mans (rear seat removed etc).

 

Lined up on an airstrip and the 5k pulled away. Would of been a car length by the end of the eigth mile.

[tioklou]

In my opinion the std carb is the restriction point on old man's engine.with a weber dgv it is very possible to be much closer....

[coln72]

I use the term standard loosely - it looked like a 4k carb externally...... can't say no more as I might want to get back into motorsport :) and we have got to get an advantage.

 

Basically it comes down to torque - mine was producing more of it down where I could use it so I could drive away off the line - the top end was not much different although the 4k felt like it had more as it was an all or nothing engine. It was a case of waiting, waiting hit 4000rpm and HELLO power. A 5k will always out grunt a 4k due to the extra torque a 5k brings to the table.

 

If you want to get really technical, I believe that the bore/stroke ratio of a 5k is a lot better for performance than the bore/stroke ratio of a 4k. Allows a 5k to rev nicer.

[tioklou]

i agree with you...5k has more torque because of his capacity but i have heard that a 4k engine can rev more because of his 75X73 bore and stroke.. it's a "square" engine...

[Hiro Protagonist]

i agree with you...5k has more torque because of his capacity but i have heard that a 4k engine can rev more because of his 75X73 bore and stroke.. it's a "square" engine...

 

A 5K is essentially a bored 4K, which makes it oversquare, and oversquare engines tend to rev well

[Trev]

A 5K is essentially a bored 4K, which makes it oversquare, and oversquare engines tend to rev well

 

Why my bike revs to over 18'000rpm :D

 

Bore x stroke: 48.0 x 34.5 mm

[tioklou]

you are right Trev... :-) but i have another question.. does piston size affects reving? 4k and 5k have the same stroke but different bore...