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Having a set of rods made for me, in my spare cupboard there was a RS4 rod and S4 rod I sent them both to the company so they can get the right measurements, They have now told me that there is a 1mm difference between the two rods At the big end bearing, Well after spending a load of money on Audi Rs4 conrod Shells I will have to go for RS4 rods but will they fit the S4 crank as bought RS4 rods as a upgrade to the S4 and was told they would fit. PLEASE HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!

musty1 wrote:Having a set of rods made for me, in my spare cupboard there was a RS4 rod and S4 rod I sent them both to the company so they can get the right measurements, They have now told me that there is a 1mm difference between the two rods At the big end bearing, Well after spending a load of money on Audi Rs4 conrod Shells I will have to go for RS4 rods but will they fit the S4 crank as bought RS4 rods as a upgrade to the S4 and was told they would fit. PLEASE HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!

600 brake not enough for you then?

IIRC MRC reckon the standard S4 rods are safe upto 600.

Personally I wouldn't have bothered with RS4 internals, just stick with stock S4 rods and pistons.

Mihnea's internals are all stock IIRC and he's at 600 plus change.....

The S4 conrods are not safe at 600 hp. I know a few engines and those had less than 500 hp, and those broke a rod.

it not about 600 bhp being enough(but it's not ) it is about being safe as okkim states S4 are not good for 600 there good for about 500-550 mihneas at 511bhp you dont want to spend money doing your engine to what ever power wether being 600 or 700 you don't want to find once you have done the engine and start it up and start to run the power through it it breaks and you have start again RS4 rods are good for 600 to 650 it's just a safe bet after all.

agreed, do it properly & only do it once! rather time consuming and not especially cheap to take the engine apart again because something simple has broken! give mrc a call about the rods, best way to get the right info quickly.

Well that's me educated then - ta for that!

I could swear that Doug had posted Mihnea was now upto 600 brake, ah well!

So, given that your big end is a different diameter - I take it that means the crank is different?

Good job I'm only after 400 brake - I can do without 16K miles a year of sub 20 mpg If I went any higher

I have both RS4 and S4 conrods, but those are on the way to the machinery. I asked them to measure the big ends, because I'm going to put S4 custom rods to RS4 crankshaft. I'm pretty sure (and I hope) that the bearing size is the same.

There's nothing custom about SPM rods, they're just Eagle rods, as sold by Eurospec and a few others...

Well, I meant that those are not OEM rods...

Do you have knowledge of the S4 and RS4 bearing sizes?

Interesting the sizes are different? Surely MRC can comment on this? I thought people had fit RS4 rods to an S4 before?

The s4 and rs4 crankpin is the same ! The the bigend on the rod is different! You want the rs4 rod with the rs4 sputter bearings as they make up the difference on the S4 crank top and bottom. Simple as that....not rocket sience

What are the big end sizes in S4 and RS4?

Had RS4 rods and pistons on my S4 once..... No problems at all

That's what I thought also, thanks for the info! I wish that people would not give any misinformation if they are not sure.

I was wondering that why it is not mentioned in the RS4 SSP, because all the other changes are. Bigger conrod bolts, bigger top end, crankshaft is different metal, stronger bearing caps and so on...

Okkim
The company has not given the misinformation there is a 1mm difference they just did not know the sputter shell makes up the different, and I did'nt until I spoke to someone after I posted this on the forum.

Yes it is simple once you know (just like questions on who wants to be a millionaire always easy once you know)