Cylinder 1 help

[s3james]

Hi Guys, I sent my 2001 s3 amk engine off to revo Thursday morning as they are extremely near to me. Got it back yesterday. was meant to have a stage 1 remap put on.... but, due to a compression test and cylinder 1 being 100psi, they said it was too low. cylinder 2,3 and 4 being around 150psi.

Should cylinder 1 cause any issues to the performance of the car? all seems fine with it and I am unsure. I did last night have a play with a brand new s line a4 and audi tt tfsi, which im happy to say I did beat =)

I have a friend who will be doing a compression test tonight or Saturday to double check the figures.

Also, the car is holding at about 0.7-0.8 bar boost (unsure if this is what it should be?) car is standard apart from fmdv008, k&n panel filter and de-resonated hard boost pipe.

My future plan is to rebuild the engine anyway with forged pistons, and new rods etc as I want a reliable 350-400bhp car and if I wish to be able to go beyond that. I am reading through previous builds for ideas on best parts and costs

 

[<tuffty/>]

150psi is low let alone 100psi dude... sounds like you have a very worn engine...

Do a leak down test too...

A healthy 20v normally clocks in at 180ish psi... the low compression will definitely be affecting performance as all the combustible stuff will be leaking past the rings and/or valves and giving less of a bang....

As your car is std then the affect may not be as noticeable but it will be down on power for sure...

Props to Revo for doing a compression test though... there are a lot of 'tuners/mappers' that wouldn't have even checked fault codes let alone done a compression test to check if the engine was ok for mapping

Holding boost is not a measure of how good an engine is... 0.8 bar is std boost, its plausible the N75 is having to work a little harder to maintain that too... there is enough margin at std levels of tune to keep std boost going...

<tuffty/>

 

[s3james]

Thanks for the info Tuffty, im glad they did check this, cost me enough to have the whole car serviced. Looks like the rebuild will be coming a fair bit sooner than expected then.. Taking a read through your build is giving me a huge amount of info into it all. After Christmas, im going to be placing a nice order on parts now.. just needs to do some research on what parts I shall need, as im unsure

 

[<tuffty/>]

Depends on what your end game is mate tbh... basic engine rebuild will cost the same no matter what you do... it will be the head work that could impact the cost but that depends on what you plan to do going forward.

<tuffty/>

 

[s3james]

well end result is going to be more than likely to buy a new engine, get that stripped down and rebuild fully forging it all, that will allow me to still drive mine for the moment, then once its ready, I can switch them over in a weekend hopefully. that way I can also concentrate on the bodywork, and getting the looks to a better standard.

 

[Alex C]

I had the same problems a few weeks ago; as it happened it was in for a head refurb, rods and rings with Bill anyway so it wasn't a big deal for me. Cylinder 2 was down at 155psi with a 60% leak on the leakdown test

 

[<tuffty/>]

The workshop was brimmed with red S3's for a couple of weeks... made a change from all the silver ones

<tuffty/>

 

[Alex C]

yeah I did notice the other one in there when I dropped mine off. I didn't venture into the garage to see if yours was lurking in there though

To be honest I felt a bad S3 owner when Bill phoned to tell me the state mine was in; I thought I looked after it fairly well and don't really understand how it got into such a bad state. I did ask Bill if it was a common thing for a car with 140K on the clock to be that bad - but he confirmed my suspicions and told me "no, its not common - it's just ****!" lol

It'll be on 5k oil changes from now on rather than the 10K