VTT GC highest mileage cars

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colo_evo

Corporal
Jun 6, 2017
131
Saw the mp thread and wanted to see how the gc's are holding up at higher mileage. Mainly looking at the standard gc's, but it would be good to see how the lites are holding up too.

Post up your experiences.
 
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martymil

Lieutenant
Free Vendor
Sep 6, 2017
952
Down Under
I have around 10k on them running 25 to 28 psi and they are not the latest versions either.

They are awesome on 93 and make more power the car can handle
 

MattGu40

Private
Jan 29, 2018
28
i have got about 10k miles on them aswell, From canada No issues no smoke exept from the clutch
1st version
 

colo_evo

Corporal
Jun 6, 2017
131
Got 35k on my GC 1.0s but do yourself a favour. Buy something else. I dodged a bullet.

Thanks for the input. 35k is pretty good mileage, yet you recommend another brand. How come?

Knowing what you know now which twins would you go with? Single is out of the question, to much lag.
 
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[email protected]

800HP Club (N54)
Platinum Vendor
Oct 24, 2016
782
Scottsdale, AZ
I assume you're looking for third party numbers, not so much from us. That said we have a couple guys in the 35-50k range, but most with less mileage. Between the age of the platform and the power potential of the turbos, most people with GC level (full) do tend to move the car to more of a fun toy vs. commuter that has some ass. We get more reports of longer mileage from the Stage 2 crowd, I think our highest there is a little north of 70k, and especially the Stage 1 crowd which makes sense when you think of how the car would likely be driven.
 

Torgus

Captain
Nov 6, 2016
1,197
Boston
Single is out of the question, too much lag.
Very laggy. Stock motor & head, 500wtq at 3.5k and 800wtq @ 4k. If this was rev'd out to 8.2k that would be north of 700whp for about half the vehicle's RPM range:

Imagine what the dyno would look like with a worked head and high lift cams.

My point being is if you size the single correctly for your desired application lag should not really be that much of an issue. Tons of low end tq is just going to bend your rods and your tuner is hopefully going to tune some of that out anyways if they are competent. A single is are inherently more reliable. But twins do have a place in the market so if you are set on them there are good options available.

The new @[email protected] or @Hydra Performance twins are what I would use. Given the cost/time of labor to install twins I don't see the point of going with products which have had a checkered past in terms of failure rate. There is also the issue of if you post to social media certain companies warranties are potentially compromised. So don't post about an issue on the forums if you want support from the vendor.
 
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fmorelli

Colonel
Staff member
Aug 11, 2017
2,326
Virginia
Very laggy. Stock motor & head, 500wtq at 3.5k and 800wtq @ 4k. If this was rev'd out to 8.2k that would be north of 700whp for about half the vehicle's RPM range. Imagine what the dyno would look like with a worked head and high lift cams.
Spoolstreeter buys head. Starts to see the world through ported and polished lenses, with lots of lift and duration.

Filippo
 

buster84

Corporal
Mar 24, 2018
240
I have 5k miles on my GC's in a little over 1 year. I mostly drive the BMW when I'm going to class or on the weekends otherwise if my trip is longer than 5 miles I take the Camry. Although I havnt put that many miles on them I've definitely put them through alot of heat cycles. I also have my tune setup for 25psi when on 93 and 28psi when I spend the time to drive 15 miles to my closest e85 station. (I wish the e85 station closer) I've probably spent 90% of my miles using 93.
 
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Asbjorn

Sergeant
Mar 10, 2018
359
Europe, based in China
The wheels seem to be what you need to worry about. AFAIK from a technical point of view the current GCs have the best wheels available on the market (for stock location journal bearing twins at least).

You can't really use the milage data from old 2.0s and 1.0s in here, as you can't buy those products anymore.
 
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colo_evo

Corporal
Jun 6, 2017
131
The wheels seem to be what you need to worry about. AFAIK from a technical point of view the current GCs have the best wheels available on the market (for stock location journal bearing twins at least).

You can't really use the milage data from old 2.0s and 1.0s in here, as you can't buy those products anymore.

What was wrong with the wheels on gen 1 and 2? What's changed in the current offering? Are they referred to as gen 3 now?
 

buster84

Corporal
Mar 24, 2018
240
What was wrong with the wheels on gen 1 and 2? What's changed in the current offering? Are they referred to as gen 3 now?
Gen 1 had issues with the exhaust turbine breaking. Version 2.0 is mostly rebuilt 1.0s and some new ones with new castings. Tony was custom making the exhaust turbines for these turbos. I'm guessing version 3.0 are now more mass produced turbine wheels along with other changes they made (I havnt looked up the specs on the new ones since the 2.0s)
 
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Asbjorn

Sergeant
Mar 10, 2018
359
Europe, based in China
What was wrong with the wheels on gen 1 and 2? What's changed in the current offering? Are they referred to as gen 3 now?
So the latest 2.0 (not same as old 2.0) use Mar.M wheels. More info here:

 

[email protected]

Lieutenant
Free Vendor
Dec 7, 2016
626
St. Louis, MO USA
Regardless of your iteration of GC's, look into the turbine housing inlet next time they are going into or coming out of servicing... or even when a new set is purchased. The attached is what you will see and is certainly an extremely large factor with their issues. Once this is cured, that is the machining and turbine placement is like the OE's designs, they will find the quality will sky rocket (assuming the rest of the build is solid).

This goes for even if they choose to use only the good ole tried and true inconel wheels, or Mar-M, as those differences in themselves are not the core of the problem. The core of the problem is that the wheel inducer is hanging significantly into the turbine housings volute, much of the contour is even exposed, and turbine back side is extended well beyond the housing wall. Until this is all corrected then sooner or later they'll meet the same fate. FWIW the GC 1.0 housings actually seem to have a (slightly) better fitment IMO, but still quite horrendous compared to a native example.

Thanks,
Rob
 

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buster84

Corporal
Mar 24, 2018
240
For those not watching the market place, here's a freshly rebuild set of VTT GC 2.0's

Filippo
He should mention in his forsale ad if his version of the 2.0's has the new Mar-M246 propellers because if it doesnt his asking price might be to expensive considering the price is only $3300 with the Mar-M246 propellor, different compressor housing casing and a of year warranty.

Mine are the GTX28 propellers before the new Mar-M246, so im not sure if there is also a performance boost, or just extra heat resistance, but with the GTX28 propellers they already move massive amounts of air! I love hearing the turbos spool up hard with the loud blow off valves releasing lots of air with just light accelation lol. Ive never beein in a single turbo car bmw yet, so I have nothing really to compate it to, lol.
 

[email protected]

800HP Club (N54)
Platinum Vendor
Oct 24, 2016
782
Scottsdale, AZ
Single is out of the question, to much lag.
Most singles will have a lot more lag. People often mix up spool and lag. Spool is rotordynamically driven, meaning where in the RPM band you make power. Lag is responsiveness, when you make power, or "time-to-torque". Spool and lag are certainly in bed with one another, but are not the same thing. A dyno plot will show you spool, not lag. You guys know this, just not all of you have put 2 and 2 together. Think of the big supra drag cars you see staging at the line. How long do they spend spooling up the turbo? Now imagine how that 1/4 mile time would change if they had to start the race at a steady-state 5 mph. Great dyno plots though, and perfect for their application, but not useful for real-world driving (most of the time).

If you want a responsive vehicle, you want turbos that spool early in the RPM band (important!) and have extreme responsiveness (important!!). This translates into a very high degree of "driveability", and for most people it means more fun. Other platforms (especially NA) spend a lot of time and energy pursuing that responsiveness. There is a reason for this.

IMO large turbo small displacement engines are boring to drive anywhere but a track or flogging it 10/10. Turbo design and motor tech has certainly made it a lot better than it was say, 10 years ago, but on anything but a race car a laggy turbo mostly just adds angst when trying to perform real-life maneuvers, like pulling out in front of someone in traffic and needing a reasonable amount of power right now. Most of you have experienced this. Pedal on the floor.... wait.... wait.... car getting closer in your mirror..... Oh, hey, there's some power, thanks for showing up! You can reduce a lot of this frustration with predictive driving habits -which is always a good idea- but a low-lag turbo system wins all day long IMO.

Now on a dedicated 1/4 or 1/2 mile race car, who cares, all we want to do is move the most air possible, she could take as long as she wants to spool up, once it's go time it'll stay spooled for the whole race. This would be why we have large turbos on the Stage 3 kit on the shop race car.

On the V1 GC series the lites had significantly better spool than the full GC's. The GC V2.0's close the gap considerably. So much so, that's what's going on my personal car (still have the old Stage 2+'s on her!). To each their own, of course. I generally talk with customers about power goals, how they actually use the car, what transmission, fuel, etc and help them sort out what's the better fit for them.

Chris
 

Asbjorn

Sergeant
Mar 10, 2018
359
Europe, based in China
Most singles will have a lot more lag. People often mix up spool and lag. Spool is rotordynamically driven, meaning where in the RPM band you make power. Lag is responsiveness, when you make power, or "time-to-torque". Spool and lag are certainly in bed with one another, but are not the same thing. A dyno plot will show you spool, not lag. You guys know this, just not all of you have put 2 and 2 together. Think of the big supra drag cars you see staging at the line. How long do they spend spooling up the turbo? Now imagine how that 1/4 mile time would change if they had to start the race at a steady-state 5 mph. Great dyno plots though, and perfect for their application, but not useful for real-world driving (most of the time).

If you want a responsive vehicle, you want turbos that spool early in the RPM band (important!) and have extreme responsiveness (important!!). This translates into a very high degree of "driveability", and for most people it means more fun. Other platforms (especially NA) spend a lot of time and energy pursuing that responsiveness. There is a reason for this.

IMO large turbo small displacement engines are boring to drive anywhere but a track or flogging it 10/10. Turbo design and motor tech has certainly made it a lot better than it was say, 10 years ago, but on anything but a race car a laggy turbo mostly just adds angst when trying to perform real-life maneuvers, like pulling out in front of someone in traffic and needing a reasonable amount of power right now. Most of you have experienced this. Pedal on the floor.... wait.... wait.... car getting closer in your mirror..... Oh, hey, there's some power, thanks for showing up! You can reduce a lot of this frustration with predictive driving habits -which is always a good idea- but a low-lag turbo system wins all day long IMO.

Now on a dedicated 1/4 or 1/2 mile race car, who cares, all we want to do is move the most air possible, she could take as long as she wants to spool up, once it's go time it'll stay spooled for the whole race. This would be why we have large turbos on the Stage 3 kit on the shop race car.

On the V1 GC series the lites had significantly better spool than the full GC's. The GC V2.0's close the gap considerably. So much so, that's what's going on my personal car (still have the old Stage 2+'s on her!). To each their own, of course. I generally talk with customers about power goals, how they actually use the car, what transmission, fuel, etc and help them sort out what's the better fit for them.

Chris
Out of curiosity, how does the N55 GC compare to the N54 GC / GC lites in terms of lag then?
 
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