All Things Mk5 > Mk5 General Area
Down on power....
Teutonic_Tamer:
Robin, have you ever been on any other rollers? Maybe JKM have had theirs recalibrated since your first run way back when. I am aware that DD rollers are supposed to be the most tightly regulated, by the manufacturer - and if JKMs were being "over generous" when initially installed - a subsequent recalibration might have down-corrected their readings. I simply mention this because you seem to be saying that the stage 2 "seems better" - so your butt-dyno is telling you the stage 2 is better, but the RR is telling you the opposite.
Engine oil - what brand, type and spec oil do you use? And what is your oil consumption like? Do you religiously keep it topped up to the max by adding small amounts frequently, or do you let the oil get fairly low and then add quite a lot?
Onto the specifics of oil in the turbo discharge pipe. Firstly, you stated "Inlet seals removed and cleaned and all ok in that area now" - but do you mean the seals on the pipework, the seals on the turbine shaft, or do you mean the valve stem oil seals for the "poppet valves" in the cylinder head?
Regarding actually finding oil in the turbo discharge pipe, I think this is fairly common. I found oil in mine, and inside the standard intercooler - but it wasnt much. Maybe one or two tablespoons, which is fairly reasonable. However, I wonder if the stock GTI intercooler has something to do with this? I personally reckon the stock i/c is slightly restrictive, which can cause a slight backpressure on the inlet side of the turbo. Since upgrading mine to the S3 cooler and twintercooler, I do notice a much more rapid rise in turbo boost - which prooves that the airflow through the inlet tract is much freer and less restrictive. Maybe this is also having an effect on the way that the oil vapours from the crankcase ventilation system are not getting to the combustion chambers quick enough. Think of having a hot shower in a closed bathroom - the shower will steam away, but if you have a mega powerful extractor fan immediately above the shower head, it will suck out all the steam. However, if you have a clogged, weedy fan, the steam wont get sucked out, but will condense on your bathroom mirror, and then dribble off the bottom edge.
Onto a couple of other issues. Did JKM plug in a VAG-COM to check for fault codes? And did they carefully monitor the N75 cycle?
Regarding the actual replacement of the turbo - only you can decide which is the best way. However, I would personally never recommend any second hand turbo, no matter how well the previous owner claimed to have looked after it. You only need to recall some of the threads on the other GTI fourm (revving engines whilst stationary, "blipping" throttles, correct turbo cool down - I even think that you mis-understood about the cool-down procedure), and it simply showed a fundamental lack of knowledge on how to car for an engine in general, let alone the specific requirements of a turbo. If I were forced to only take a 2nd hand turbo, then I would send it to a specialist turbo re-builder for a complete overhall and warranty.
If your original turbo is knackered, I would personally seek a specialist recon, or go for the genuine new VW part. Yes, I understand your POV that the official VW 2 year warranty will probably be void - but it is the "peace of mind" from getting an OEM supplied part - you can pretty much expect an OEM new turbo to last a long while, but how long will a slightly cheaper second hand one last. The labour charges will be the same, but if the 2nd hand one doesn't last, then someone will be paying the labour charges all over again.
Teutonic_Tamer:
--- Quote from: Top Cat on November 01, 2008, 12:24:31 am ---yes the ED30 does have stronger internals but the compression is better on ours. i believe.
--- End quote ---
No, no, no, NOOOOO. :scared: :party: :nerd: :P :sad: :fighting:
The Edition 30 engine does NOT have stronger internals. It has different internals, and only some. The durability of the Ed30 engine is exactly the same as the standard GTI engine.
Only the Audi S3 engine has stronger, reinforced internals, along with a stronger cylinder block/crankcase. :rolleye:
Yes, compression ratios are different, but that is for a specific reason, and nowt to do with any durability allowances.
Teutonic_Tamer:
--- Quote from: RedRobin on November 01, 2008, 12:25:34 am ---....
But why is higher compression better?
--- End quote ---
The compression on the standard GTI is higher than the Ed30, and the simple reason is down to peak pressures in the combustion chamber - which will be nigh-on identical in both engines.
The reason the standard engine has a higher compression is because the turbo is smaller. Smaller turbos simply mean better "low-down" power. But the small turbo tends to make the engine run out of steam at higher revs - due to the fact that smaller turbos can flow a smaller volume of air - so the higher compression ratio compensates.
The Ed30 engine has a lower compression ratio, simply as a reverse reason over the standard engine. The Ed30 has larger turbo. This can flow a larger volume of air at higher revs, hence the lower compression is required as a kind of "safety net". You could argue that VW should have kept the higher compression ratio of the standard GTI engine, and simply lowered the turbo boost - however, they know very well of a very simple word - "remap". High turbo boost + big turbo + high compression ratio = much shorter engine life.
T88OMM:
KO4 KO4 KO4 :mad: :jumpmove: That would be my decision but then again I can never get enough POWER! :jumping: The second hand KO3 sounds like a viable option and a relatively inexpensive one at the same time. As you say you dont want 300 neddies going through your front wheels so this has gotta be the route to go down! :happy2:
RedRobin:
--- Quote from: WhiteGTI on November 01, 2008, 08:14:32 am ---Now your making me nervous with my Stage 2 !!!!
--- End quote ---
....I'm very confident it isn't down to Revo Stage2. Boost is set at 7, which isn't at all excessive. Also there are plenty people running Revo's Stage2 on the 2.0T FSI with very similar mods to mine (you for example!).
The boost graph shows that it's spiking at 1.2 bar and then dropping off badly from 2,400 revs.
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