VTT GC 2.0 Review

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martymil

Lieutenant
Vendor
Sep 6, 2017
699
Down Under
I've been running the current gc 2.0 turbos for over 6 months now without issue at 26psi on e20 on a decompressed motor making 360+rwk.

Doesnt sound like much but that's on our heart breaker dyno dynamics dyno so add about 10% min for the freedom dynos.

This is just 93 with a splash on e85 to make e20 for knock control.

Look at it this way no other motor has done more with a stock head and cams even with stock compression here is oz as far as I'm aware consistently run after run.

No matter what i throw at these they are still going strong after 5000+ miles with the right supporting mods and the right tuner and this is where the men are separated from the boys.

These turbos make awesome power but they need to breathe and have unrestricted flow in every way, dont expect to run a stock ic.and inlets or some cheap chinese knock offs to work properly,

This is just my experience with these and they have been working awesome.

I give credit where it's due and I know vtt have gotten their recipe right with these and I highly recommend them.

Btw when I say 5000 miles that includes over 100 dyno sessions and its not hwy ones but extremely fun miles of utter torture which is very different.

Keep you guys updated but would love to hear from others with the current crop of gc's.
 

Asbjorn

Corporal
Mar 10, 2018
217
Well, we are just running the lites, but given the latest Mar-M246 wheels, I certainly don't know of any upgraded twins with better wheels on the market as of today.
 
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martymil

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Sep 6, 2017
699
Down Under
I could have possibly ran the lites with my setup and still made the same power because of the fuel quality limitation but at least I know if I want to turn it up I can with a tank of e85.

Bloody brilliant turbos, I'm glad I made the switch.
 

jts1981

Private
Jan 29, 2018
29
NYC
Glad to hear the turbos are treating you well! I agree these need some good airflow. I went with the VTT larger inlets and outlets.

I've been running them for a few months but unfortunately that was winter time, and only on V1 map from BQ. I've also been wrestling with a few things like 2A7, 2A79 codes , and a fuel pump code with my Walbro 525 pump. I barely got into boost just to be safe so thats a little bit of a bummer.

Good news is thats all been resolved and I should be picking up the car on Monday or Tuesday and I CAN NOT WAIT to get into some boost and get some logs done ASAP.

Also Chris and Tony from VTT have been nothing less than stellar. I always get a quick reply for my random inquiries .
 
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Panzerfaust

Sergeant
Jul 3, 2018
387
Chicago
Even though I dont run them, I'm glad to see positive reviews of these turbos. I was heavily considering them before my purchase of a different set, but it's good to see more evidence that more twins are just as good of a choice as a ST setup imo. I truly think that nowadays the stigma about "hybrids" / twins (which personally I don't know that we can still really call the GC line or 1Ks "hybrids", since they share nothing in common with the factory turbos other than connection styles and WG actuators) is outdated when considering any of the big names for twin options, and hopefully Hydra's turbos will prove to be just as reliable.
 

martymil

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Sep 6, 2017
699
Down Under
Like any turbo or turbos it really depends how its tuned and setup that determines how long they last.

I've seen single setups let go when ran at the ragged edge but less likely as most dont even see them run at 70 % what they are actually capable off.

Twins need a lot more attention to detail and a lot more finessing in their setup, but when done properly the gains are very rewarding.

But if you are going to spend the money twins can be just as reliable as single, I think the days of crappy twins are over and lessons have been learned from all the failures and with twins getting cheaper due to high competition and the tuners having a good grasp of tuning these cars these days the only winners here are the consumers.
 

Itsbrokeagain

Corporal
Jan 28, 2018
127
Strong Island
I wonder how many sets of the 1.0s are still out there...I think we're 2 years in on a set from the first batch of GC 1.0s and have had zero issues. But like @martymil says, we have no restrictions in or out. All Vargas parts going in, dual pumps (LP and HP), and still pushing through an original Helix FMIC thats like 9 or 10 years old at this point. Justin of Vargas fame did our tune and we're running around on 93 at 22lbs. Could turn it up on E85 but the 550 clutch will prolly give up the ghost first. No smoking/blown up turbine wheels, nothing.
 
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Torgus

Lieutenant
Nov 6, 2016
889
Boston
I've been running the current gc 2.0 turbos for over 6 months now without issue at 26psi on e20 on a decompressed motor making 360+rwk. This is just 93 with a splash on e85 to make e20 for knock control.
Do you need E20 for knock control at only 26psi? VTT didn't need any at 30-32psi peak on pump 93 stock block and you have lowered your compression which should allow for even more boost on 93 and not need any E85. Any reason you are not running them harder?

What do you think it would put out in freedom units on a dynojet?


Justin of Vargas fame did our tune and we're running around on 93 at 22lbs.
Why are you only running 22lbs of boost? That is really low for GCs on 93 octane and a stock block isn't it? https://www.bummerboost.com/showthread.php?77159-VTT-GC-Testing-on-93-Octane-568-whp

32psi...10psi off, that is a lot of power left on the table

22 psi: 509 whp 478 wtq
25 psi: 543 whp 519 wtq
30 psi: 570 whp 560 wtq

Is it your clutch? You are not using roughly 60hp & 80tq. That is a ton left on the table.
 

martymil

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Sep 6, 2017
699
Down Under
Our fuel is not like usa fuel, its utter rubbish.and a huge limitation.

Anything over 20 psi and max of 5 deg of timing sees massive timing corrections

I dont like to run my turbos hard as I built my car for power and reliability.

I'm running 8 deg of timing so e20 makes my logs very clean, I could run less timing and less E but I get a fair drop in power.

I can run as low as e13 but I start to see timing corrections anything below that.

I think I've got the perfect street setup in my opinion and is totally reliable and breaks traction whenever I want running michelin sports cups 2 tyres which are sticky as.

Any more power is useless and is totally undrivable unless all you want is wheel spin but I can turn to e85 for that when ever I want.
 

langsbr

Lieutenant
Apr 5, 2017
814
Do you need E20 for knock control at only 26psi? VTT didn't need any at 30-32psi peak on pump 93 stock block and you have lowered your compression which should allow for even more boost on 93 and not need any E85. Any reason you are not running them harder?
Eh, that's a broad statement. You can run more boost with less timing, but if less boost and more timing makes more power, why not go that route? I think they were running at most 4 degrees on the pump gas test, which is nearly nothing. I would think that would present its own issues with regards to EGTs, and I'd be happier running 22 - 24 psi on 8 or 9* on E20. He's probably using E20 just to help octane a tad.
 

Itsbrokeagain

Corporal
Jan 28, 2018
127
Strong Island
Our fuel is not like usa fuel, its utter rubbish.and a huge limitation.

Anything over 20 psi and max of 5 deg of timing sees massive timing corrections

I dont like to run my turbos hard as I built my car for power and reliability.

I'm running 8 deg of timing so e20 makes my logs very clean, I could run less timing and less E but I get a fair drop in power.

I can run as low as e13 but I start to see timing corrections anything below that.

I think I've got the perfect street setup in my opinion and is totally reliable and breaks traction whenever I want running michelin sports cups 2 tyres which are sticky as.

Any more power is useless and is totally undrivable unless all you want is wheel spin but I can turn to e85 for that when ever I want.

What he said. We left timing at or near stock levels and the car makes great power and pick-up, it was showing some ever so slight timing retard in some cylinders so we dialed it back 1psi and let er rip. My client beats the absolute piss out of the car when he does drive it, so we tuned it for reliability, and to keep the tire life up (even though at 22psi its already pretty limited with a Quaife in the rear).

Mixing in 5gal of E85 makes the car run phenomenal and there are zero drops across the board, so we left it be.
 

Itsbrokeagain

Corporal
Jan 28, 2018
127
Strong Island
Do you need E20 for knock control at only 26psi? VTT didn't need any at 30-32psi peak on pump 93 stock block and you have lowered your compression which should allow for even more boost on 93 and not need any E85. Any reason you are not running them harder?

What do you think it would put out in freedom units on a dynojet?




Why are you only running 22lbs of boost? That is really low for GCs on 93 octane and a stock block isn't it? https://www.bummerboost.com/showthread.php?77159-VTT-GC-Testing-on-93-Octane-568-whp

32psi...10psi off, that is a lot of power left on the table

22 psi: 509 whp 478 wtq
25 psi: 543 whp 519 wtq
30 psi: 570 whp 560 wtq

Is it your clutch? You are not using roughly 60hp & 80tq. That is a ton left on the table.
the 550i clutch was shown to slip at levels over 450hp, we're sitting at over 500 now and laying some abuse in it, so only time will tell.
 

martymil

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Sep 6, 2017
699
Down Under
I could never run anything over 23psi on the stock DMFW due to false knock.

My 550i clutch couldn't handle 22psi and would just try and cook itself it was virtually brand new,
we had to switch over to the xclutch and single mass flywheel to get more.

This is before I built the motor.
 
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Panzerfaust

Sergeant
Jul 3, 2018
387
Chicago
Like any turbo or turbos it really depends how its tuned and setup that determines how long they last.

I've seen single setups let go when ran at the ragged edge but less likely as most dont even see them run at 70 % what they are actually capable off.

Twins need a lot more attention to detail and a lot more finessing in their setup, but when done properly the gains are very rewarding.

But if you are going to spend the money twins can be just as reliable as single, I think the days of crappy twins are over and lessons have been learned from all the failures and with twins getting cheaper due to high competition and the tuners having a good grasp of tuning these cars these days the only winners here are the consumers.
Yep, I completely agree. My main point was what you mentioned in the last paragraph, where I think the R&D and field experience is to the point where any solid set of twins will be just that - solid. The tuning and supporting hardware is definitely important too, as with any modifications going on a car that will see "abuse" imo. I think as long as you're running the right sized inlets/outlets (I'm shocked at the amount of people on FB who don't install these while doing turbos and stick to stock) and dont run a kill tune or half-baked tune on a daily driver then theres no reason twins wont see an excellent lifespan. Just in the MMP FB group there's a list of the recorded highest HP guys and most of them are over 20k+ miles running 28+ PSI.
 
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martymil

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Sep 6, 2017
699
Down Under
I found that miles mean nothing as I can run 34 psi on twins and make them last thousands of miles
on hwy as they barely ever see any major boost.

Now track miles on spirited canyon/mountain runs is very different and this is where the turbo manufacturers are set apart.
 
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V8bait

Sergeant
Nov 2, 2016
335
Texas
Thanks for the update, not all the twins explode like people seem to think, although it is a bit risky strapping two spinny things to the engine vs only one of them the fun factor can't be overstated lol. Who builds the engines down under? Seems to be a few guys having good success with them lately.
 
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