UrS4 2.2T Avant project

[Thuppu]

[Error404]

[AndyP]

Alex, no, thay are 2618 alloy... should hold under great "pressure" Don't know how much the pinns can take, they are 22mm though, and lightened. This kit was made back in 05 and have been laying around in a shelf since that. Got them really cheap. I want ot modify the top, mill off a bit to make higher CR, so I was in contact to Ross and they told I could safely take off 3,7mm of the piston top land. With 155mm rods I would take less, but either way that mean I have to mill off the block also. Have to measure the block before anything, if it's sligly more than 236mm(like 236,6mm or something) then I may go with 159mm rods. That's why I asked this: http://www.s2forum.com/forum/showthread.php?t=68839

All the blocks I've measured ( 4off now ) have been around that figure, I'm sure JP told me that the factory figure for deck height is 236.5mm not the commonly quoted figure of 236mm.

I was doing some rough calculation the other night and I think you can use std. pistons with the 155mm rods. I need to double check this and also work out the CR it will give. If it all works out, I'm seriousley thinking of building a 2nd bottom end and using std. pistons. I don't plan on doing more than 500hp so they will do that OK, and also if they are bored correctly should result in zero oil consumption.

[Thuppu]

All the blocks I've measured ( 4off now ) have been around that figure, I'm sure JP told me that the factory figure for deck height is 236.5mm not the commonly quoted figure of 236mm.

I was doing some rough calculation the other night and I think you can use std. pistons with the 155mm rods. I need to double check this and also work out the CR it will give. If it all works out, I'm seriousley thinking of building a 2nd bottom end and using std. pistons. I don't plan on doing more than 500hp so they will do that OK, and also if they are bored correctly should result in zero oil consumption.

Yes, that should work. 235,55mm seems to be the total heigt with stock pistons, so you could mill off the deck a bit.

In my case it seems that if the block is 236,5mm after decking it and if I would use 159mm rods and want to use a 0,8mm over deck squish, then I would need to take off 2,85mm of the pistons.

[Thuppu]

-9 degrees celsius today, and the car started quite well with E85. Had to hold the rpm's at 1500-2000 for a half minute or so, other wise the engine stalled. But after that it runned fine idle. Quite good job by Dmitri. Difficult to adjust E85 cold start enrichment in summer time.

[Error404]

0.80mm above deck only leaves around 0.75mm squish clearance which is quite low - are you sure?
I was advised by several engine builders not to go below 1.00mm and there was no benefit in doing so - just risk.

[Thuppu]

0.80mm above deck only leaves around 0.75mm squish clearance which is quite low - are you sure?
I was advised by several engine builders not to go below 1.00mm and there was no benefit in doing so - just risk.

No, I'm not sure. I was thinking the squish backwards. Was remember that stock squish is about 0.80mm, and a small squish is good, but I guess it's not a problem with E85..? What I know, engine effiency should be better with tight squish, and it should also bee less knock sensitive.

BTW Alex, I did a 1mm thicker washer to the oil pump and seems that the pressure maybe rised a bit, ~0,5bar.

[eske]

Rosten Performance tells that if you add 3mm washer to the pump it will increase the pressure ~1.5bar at lower revs and ~1bar on the max pressure area.

[Thuppu]

Rosten Performance tells that if you add 3mm washer to the pump it will increase the pressure ~1.5bar at lower revs and ~1bar on the max pressure area.

http://rosten-performance.no/produkt...ljepumpe-5cyl/ Ok, great. Few years back, on our finnish forum, when I ask about shimming the oil pump no one knew nothing about it. But seeems that this kind of information is secret on our forum.

[eske]

But seeems that this kind of information is secret on our forum.

I agree.

There is one 3mm washer inside the pump from the factory.. so I added one more to see the results. Just dont have the engine in the car yet.

[Thuppu]

I have now one 4mm washer there. Could try to swap to a 5mm and see how the pressure changes...

[Error404]

Be interesting to see your results

[Thuppu]

Next thursday is dyno time. Fun to see how much it gives on springboost, and nice to get someting you can compare to later.

Any bets of the powerlevel? http://koti.mbnet.fi/pro-ht/Audi_URS...4_test_run.mp4

[prj]

Rosten Performance tells that if you add 3mm washer to the pump it will increase the pressure ~1.5bar at lower revs and ~1bar on the max pressure area.

I don't see how this is possible.
The pressure relief valve is set to a certain pressure. Below that the pump is physically limited by flow.
You can not increase flow down low with just adding a shim. You are not going to see more pressure on idle with this. Only more pressure on top, but there you don't need more pressure...

However, you will have serious problems with turbo seals if you do this, especially Garrett. BTDT.

[Thuppu]

Maybe the spring is progressive and always open? Little at idle and a lot on higher rpm's...