Quote:
Originally Posted by T1M
Yep you were 100% accurate in your description of them prior to sale. I knew what I was getting.
Stock covers were machined to use instead. If one side of the cover was machined out to centre the compressor in the snout I was told the tolerance on the other side was apparently too large. When I received the turbos from the original owner and was testing it the compressor could touch the housing I found it coils on one side but could not on the other, which seems to support the claim? Either way it was corrected and the builder was happy with the compressor to housing clearance after he machined the stock covers.
I didn’t ask for balance traces, just asked what the balance figures were. I know it’s become an N54 turbo marketing point now to give customers confidence in the items as it was common knowledge the classics and perhaps other brands turbos back in the day weren’t well balanced but in other markets where this was never a problem (GTR’s, Evo’s etc) they’re not commonly supplied with turbos.
It would stand to reason that if the VSR balancer reports to 5 significant figures and 4 decimal places, ie: it reports to one ten thousandth of a G, that the 3rd and 4th significant figures are within its measurement range and well above the limit of detection. Ie: if it can report 0.0614 and the 4th decimal place is accurate - the machine is sure it’s 4 and not 3 - the 2nd and 3rd decimal places, being one one hundredth and one one thousandth of a G, respectively, would be well over 2 standard deviations from the LOD and therefore accurate. Hence mathematically speaking 0.0184 G isn’t outlandish as it’s still reporting to one ten thousandth of a G. I’m not a turbo engineer or manufacturer though so I’m just looking at this from a math point of view.
In any case I’m happy with them and the given the cost, time and inconvenience of buying items like this out of the US especially when failures occur, I think it makes a lot of sense to utilise local companies where possible.
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Good deal on cutting fresh housings to match the new 15T billet wheels- that is the really the only way you can ensure it would've been correct without upping the wheel size.
As for the old housings, as stated, if they were even .002" (.05mm) off axis it would've been very visually noticeable when new; and they wouldn't have even been shipped. 5+ years later and worn out turbos why does it seem that way to you? Not sure. Regardless we will buy them back if you have them laying around, RHD compressor housings are something we tend to ship out but never get back so the more we get back the merrier. Shoot over an email if interested- the shipping would be cheap on just those 2 compressor housings.
As for your decimal stand to reason math- it is not correct. As you maybe aware we've been very intimate with a VSR for about 4 years now, that is working with it nearly every day of every week of every month... and what you are saying just isn't right. It makes most sense that your turbos were 0.184g (which is a great balance), and that the old RB was 3.89g (which would be very very poor, like explode any minute poor; but expected for an old used failing turbo that probably has a ton of oil coked up on the turbine).
If you had the performance report, of course we could've shown this out- but not the case and that is ok we will just have to use experience to straighten it all out. Just remember most shops believe anything under 1.5g is "acceptable", this is even built into our VSR's software showing as such (ie. provides a balance under this line marker at the top of the screen). While anything under that level is thus assumed to be ok, it just is not that great and the lower the vibration levels of course the better the turbo assembly is balanced. It is typically THOUGHT to be very acceptable, a step up so to speak- to be in the 0.5g-0.9g range which is an easily attainable quickie balancing level which is quite a bit better than the high threshold. This would explain why your shop thought the old RB was 4x as bad as it should be (0.9g x 4 = 3.6g).
Anyway we took the initiative a few years back to up the ante for the sake of quality and proof that every unit is balanced the best it can be balanced (~0.1g) and provide the documentation as such, additionally most customers prefer the actual "Performance Report" than just "trust us, it was done". We too feel the same way, especially after outsourcing the function and always wondering if the shop REALLY went the extra mile or if they were about saving time. Knowing what we know today, they probably were more about saving time than putting in the effort to get every unit to the 0.1g range.
PS. Most do not provide balancing forms in this market. Most do not because they either are not building the turbos theirselves, are outsourcing some or all of the balancing function, are not obtaining the quality results as they are not putting in the time, or simply just do not have the better equipment that is needed to get the top tier results consistently.
Rob