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If you're building a hot RS4 lump, I believe you could choose to get a billet crank made to either S4 or RS4 spec then use either S4 or RS4 customs rods to suit. Is this right ie. an S4 crank will fit an RS4 block as long as you use the S4 custom rods and pistons?

If so, what do you guys reckon is the best crank to go for, S4 or RS4?

Cheers,

Andiroo

andi ... i done it when i got home

they both have the same main bearings, so yes it fits....

so its just the diference in the price of rods you go for ....

Thanks Jack So the price difference will be a factor, what else do you think in terms of crank design, RS4 against S4?

And probably the same question re custom RS4 rods over custom S4?

Cheers,

Andiroo

RS4 crank I think is alleged to be %20 stronger according to SSP.

http://www.pauter.com/titanium.htm

Mmmmm titanium rods.....

But if both were custom billet which would be the better design?

Mmmmmm, titanium rods....... couldn't agree more mate

Cheers,

Andiroo

The one with the largest journal, but then weight comes into the mix.

Might be worth asking this question on AW Andiroo, there are quite a few guys running
fully built bottom ends now.

I take it the S4 crank has larger journals, so even if both were billet the RS4 design would be a 'tad' lighter? Wonder if the difference in weight is quantifiable?

Both would be knife-edged and balanced (plus anything else you could care to think of that you could do), but the S4 one should be comparably cheaper, but at what performance cost, if any?

Cheers,

Androo

JonnyX wrote:Might be worth asking this question on AW Andiroo, there are quite a few guys running
fully built bottom ends now.

Never really been on mate, plus I'd rather the RS246 knowledge base came to the rescue if poss

Cheers,

Andiroo

Aren't the journals on the RS4 larger? if it's billet made to order I doubt either would cost more or less

MarkB wrote:Aren't the journals on the RS4 larger? if it's billet made to order I doubt either would cost more or less

I'm not sure mate, I know the RS4 rods have an 'extra shell bit at the bottom' so I assumed the journals were smaller overall.

The cost issue is that there are companies churning out S4 spec billets so the RS4 one would be slightly more expensive (not sure how much yet) as they aren't common.

Cheers,

Andiroo

Andiroo wrote:But if both were custom billet which would be the better

Cheers,

Andiroo

they would be the same mate...
the same cost..
s4 would be better as i said then you can rep my rods a bit cheaper....

the rs4 journals are smaller..by a nat's nut's
and there would be no difference in weight as they will both be spec'd to suit the job......

i sent rick the spec's tonight, so should have an mail soon.......

Thanks again mate, top bloke

Cheers,

Andiroo