GTX35R - Opinions?

EvilTwins

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Hey guys, haven't seen much talk on here regarding these new turbos yet.. What does everyone think, they seem promising to me?

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I always planned on going with GT35R's for my next upgrade but with these on the market I feel a bit torn. They are pretty damn expensive though!

I believe the GT35R was always spec'd at being capable of supporting 650hp, so with the extended flow capability of the new compressor wheel what would these be good for?
 

Blown2004Stang

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I'd use Precision's SC6176 and call it a day.. The T350 turbine wheel that precision uses actually outflows Garrett's GT series wheel in the 35R. Precision actually lost Garrett as a parts supplier, because the SC61 was outdoing the 35R, for a LOT less. Garrett told them to stop using the 35R compressor wheel in the SC61, and Precision told them to piss off. ;)

Ball bearing isn't all it's cracked up to be.. trust me.. Spool up RPM is 95% dictated by turbine size, exhuast housing A/R, and total mass flow. Ball bearing CHRA's will help transient response (how fast the transition from no boost to full boost happens), but, that's about it. From my experience, the slightly slower transient response of the non-BB CHRA makes for better traction and control.. versus the BB CHRA's "light switch" boost onset.

In other words.. If you take 2 turbines, and put one in a BB housing, and the other in a non-BB housing, they will both spool at almost identical RPM on a given engine. The BB might have a 1-200 rpm advantage, but, that's about it. The BB turbo will reach full boost about 2-300 rpm faster than the non-BB turbo.. Not much to write home about.

Travis
 
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EvilTwins

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Well the thing is is that I love the spool time with my 57's, its pretty much instaneous as far as I'm concerned. I know going to a 61mm size compressor wheel will undoubtedly mean a little bit more time for spoolup. I was just hoping that with my new 5.0 Big Bore with custom cams and ported heads would spool the GT35R's at almost the same point as what my 57's did with the stock engine.

So you really think the SC61's are close enough to the GT35R's? I want lag to be at the minimum possible but still be able to hit my goal of 1000rwhp. Please don't ask why I want 1000rwhp because I will simply respond with "Why not?" :)
 

Turbo98

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I agree that the BB turbos are over rated. Precision will even tell you that their tests have shown no improvement in spool time. If there is any, it's very small. The BB turbos were designed mainly to improve durability. I have journal bearing Precision turbos that spool very fast so as far as the turbo itself goes, it's more dependent on your wheel and housings. I seriously doubt the GT35R's will spool as fast as your 57's even with slightly more cubes. The cams will probably hurt your spool time and shift the power up the RPM band from what I've seen.

Regarding the new GTX's, it appears by looking at their compressor maps that the GTX35R will make approximately 750fwhp. So if you're looking for 1500HP, go with those for sure. BTW, how much are they?
 

Digital

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Possibly I'm missing something but is this just a slightly larger turbo with different bearings and a new wheel?
 

EvilTwins

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Possibly I'm missing something but is this just a slightly larger turbo with different bearings and a new wheel?

Are you referring to the differences between the GT35R and GTX35R? I believe the difference comes from a more efficient compressor wheel capable of supporting more air flow without shifting the left side of the flow curve (i.e. capable of spooling just as fast but able to support more air flow).

By the sounds of this I may just get some SC61's instead and save myself some $$$. The GTX35R's are ~$1800 without the turbine housing, so you can buy two SC61's for that.

Where do you guys recommend buying Precision turbos from, any of our typical vendors?
 

Turbo98

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I'd use Precision's SC6176 and call it a day.. The T350 turbine wheel that precision uses actually outflows Garrett's GT series wheel in the 35R. Precision actually lost Garrett as a parts supplier, because the SC61 was outdoing the 35R, for a LOT less. Garrett told them to stop using the 35R compressor wheel in the SC61, and Precision told them to piss off. ;)
So is Precision still using the GT35R wheels in their turbos? If not, I wonder if the performance has changed in their SC61's.
 

EvilTwins

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So is Precision still using the GT35R wheels in their turbos? If not, I wonder if the performance has changed in their SC61's.

That would be good information to confirm..

Blown2004Stang, where did you hear that information about the SC61?

In general I find a lot of people on these forums "hate" on Garrett. I could never do that, they have been the innovators when it comes to turbochargers for a long time. Do you guys feel they don't provide the same quality product anymore? Garrett has always been synonymous with quality. I would have to agree that GT series turbos are pretty damn expensive though...

Does anyone on these forums run GT35R's? I wouldn't mind hearing some first hand experience with these..
 

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