Originally Posted by Porschefile

The Precision SC61 series does in fact use a Gt35r compressor wheel, and Precision even acknowledges this (can't remember where I saw it though). To be honest, I'm not entirely sure what percentage of the GT series improvements are as a result of the center section or the new wheels. I'd tend to think it's probably pretty close to a 50/50% for each. Ball bearing center sections almost always improve efficiency as a basic rule because they usually maintain much tighter clearances on the shaft therefore the entire rotational assembly is kept from having much play. The reason that increases efficiency is because as the rotational assembly is spinning at say 100-150,000rpm, any small amount of play can have huge amounts of drag on the shaft as it rotates "out of round" against the bearing walls. Needless to say, that can result in a huge parasitic loss and the turbo would have to work significantly harder to maintain the same pressure.

IMO, the SC61 or Super 65 with a ball bearing center section is close enough to a Gt35r that it should provide you with ~90-95% or more of the same performance a Gt35r would. The turbine is very similar sized to a Gt35r's as well. The only major difference is what turbine and compressor housing are used. Gt35r's come from Garrett as standard with a T04S 4" .70a/r compressor housing. Adding a smaller T04E 3" like on the LR turbos and a different turbine housing like the Turbonetics KKK replicas will have some different effects on the overall nature of the turbo compared to a true Gt35r, but it should still provide relatively the same response (assuming a DBB center section, though I don't know if LR offers this) and overall performance/power output as a Gt35r with similar sized Garrett housings. In the import world, I have lots of acquaintences that have used the SC61 and many of them have found that there really isn't any significant difference in performance from a 35r, at least not enough for the price difference.

Well, it's not disappointment really. I like LR's turbo prices and it looks like they are offering some nice stuff. I'm just very particular about everything so I always manage to find something to complain about. I only say I'd wish they'd offer the entire Precision SC lineup as I think having more options is always a good thing. Other than that, lately I'm on a bit of a tangent over the K26 turbine housings after finding out some shocking info from various individuals such as Pauerman. I guess it just never clicked in my mind until now but, K26 housings are somewhat comparable in overall size to Garrett T25 housings, or maybe just a bit bigger than that however they are definitely smaller than T3 housings. They're much too small IMO.

The Precision SC34R is very similar to a Gt3076r. Here are the following measurements:

SC34R - Comp. 56mm (Inducer) / 75mm (Exducer) 56 Trim, and 56.6mm turbine Exducer

GT3076R - Comp. 57mm (Inducer) / 76.2mm (Exducer) 56 Trim, 60mm turbine Exducer

Anyways, both of the turbos have similar sized wheels and are rated at similar power outputs. The difference is all of the SC series turbos have a standard sized Garrett T3 center section with all of the same basic dimensions. The standard T3 center section is what's on all of the LR turbos, and the nice thing there is that means it has the proper oil outlet flange pattern (check out the links I posted above for pics of the SC series center section) to bolt to our stock motor mount. The GT series center section is smaller in diameter, therefore it sits too low to physically bolt to the mount unless the alternator is repositioned. That means all of the SC series technically would fit without too much effort. It seems that most t3/t4 turbos people are using on their 951's with a 3" T04E compressor housing have to do a bit of grinding on the housing to fit it under the stock throttle body and intake, so it's not a 100% perfect fit, but it's certainly close enough that it's worth considering.

Turbonetics replica KKK housings are designed for the standard Garrett T3 center section and they have different housings for different turbines (stock k26 as well as Garrett stage 2, 3, and 5 turbines). The KKK replica info is at the bottom of this website Lindsey's prices are nice considering you really couldn't do it for hardly any cheaper yourself, and it sure would save you a lot of trouble but, it's certainly nice to know that it can be done on your own for those that like going that route.

I myself am considering going with an SC3431RE (SC34R) with a T3 4 bolt .82a/r hotside as it would bolt to the stock downpipe, or others designed for the KKK housing and then it would only be a matter of modding the x-over with a T3 flange as well as the other typical compressor housing fitment issues. After finding out what I have about the #10 housing, and how it is about the size of a T3 .63a/r (close enough anyways), I'm looking for a bit more exhaust side flow then that so I think I'm going to stick with a .82a/r on whatever SC series turbo I decide to go with. I've done enough research to come to the conclusion that that particular combo of wheels and housings should be good enough to produce 1bar by ~3.5k or possibly a bit earlier, however it would still be good enough to push 500+whp and the top-end flow wouldn't be nearly as restrictive as the smaller KKK housings so it would certainly help the overall power curve a bit. I won't believe that Porschefile guy though until he actually gets another project completed. He has a bad habit of changing his mind on the spot. lol Honestly, one of these days I might put my money where my mouth is, hopefully sooner rather than later.

Originally Posted by special tool

Sounds good, son.
So are you saying you will man-up and build your 951?
I hope so.
Because we both know that any afflicted monkey can get big power from an RB, where is the challenge in that???

Originally Posted by Geneqco

Thanks AW... so you are talking absolute rather than gauge pressures?

Originally Posted by A.Wayne

NO mate, Gauge pressure
Life begins @ 30 psi ..........

Originally Posted by 333pg333

To run that sort of psi what extra's do you have to do to the engine for any sense of longevity?

Originally Posted by 333pg333

+2 Trav. Get on board mate, and then at least you won't have to hear anyone saying blow it out your *** until you build something!!

Originally Posted by A.Wayne

NO mate, Gauge pressure
Life begins @ 30 psi ..........

Originally Posted by Geneqco

Yes, well, I only asked to see how seriously to take your post!

Originally Posted by A.Wayne

Very seriously mate, it would have to be built like this , 1.5 low- 2 bar high boost........

Originally Posted by special tool

Any more pictures?

Originally Posted by special tool

Patrick - my brother just likes to rattle everyone's cage once in a while.

Originally Posted by A.Wayne

yes i have pics of the engine on engine dyno , i will post as soon as i can retrieve them .......................wait a min. i believe i had posted them here before ST........

Originally Posted by 333pg333

Well 36psi and longevity may not be bedfellows but let's say there's a bit of room between the 18psi that most people seem to limit themselves to and double that. What's a safe point provided you get your tune right and have decent fuel? I know AW was making a bit of a poke at you but there must be a bit more boost that can be used pretty safely that most of us are foregoing?