I think to hit 1.9 bar on vtgs you have to trick the pressure transducer since it pegs at 1.55. I believe the 63.5 mm vtgs can hit 1.9 as well. I remember Kercar hitting 5.5s (60-130, stock weight) and it was an amazing time. IIRC, he even said he had a passenger which was even more amazing. At 1.9 bar, this helps explains things. As Boggster said, no one to my knowledge has repeated this with any vtgs but haven't been tracking things that closely.

 

I can tell you that there are no Champion kits out there running anywhere close to 1.9 bar with our turbos, except on cars with built engines. Our standard GIAC software does NOT allow for 1.9 bar.....exactly how KerCar hit 1.9 bar is beyond me...unless the software was modified.

In fact, I talk to KerCar regularly, and this is the first time I've ever heard any mention of 1.9bar in his car with our turbos on it. Realistically, from the time I shipped him his ECU to the time he did the 5.5 sec run was only a matter of maybe 2 or 3 days...and that includes the transit time to Turkey. So...I'm confused.

 

Hello Tom,

We didn't touched the software or anything else on KerCar's VTG setup.

Kerim (owner) was also surprised after seeing the car boosting 1.9 bar with Giac Race file.

I think that it's not possible to get 60-130mph in 5.5sec with 1.5 bar boost.

I also think this is related with the Forge Motorsport diverter valves on the car.

It might have the stiff springs inside which obviously can results in high boost.

You can also talk with Kerim about this.

However, i was really happy with the performance of your 68mm VTG's.

I saw these turbos also performing well in one of my Greek customers car.

Thumbs up for good performing and good quality product.

Cheers,
Emre

 

I think this is speaking the truth. Good for you Emre. How did you measure the boost (1.9 bar)?

 

Would be nice if we could swap out the Map sensor or Pressure tranducer for a 5 Bar like on the GTR

 

VTG turbos? What spec and what result?

I am interested in what HP has been achieved with VTG's-any answers?
What is the possible using VTG as base? (either GT2 or Turbo)

 

Ie biggest or most efficient -so far- available wheel for a VTG turbo is that 68HTA which also requires a new compressor housing. It will max out around 445hp, which means theoretical total of 890 crankhp in optimal conditions.

 

There was an HKS boost gauge in the car, which was connected directly to the intake manifold.

 

3 bar is possible, but im not sure about 5bar, i have to try

 

Isnt 3bar close to 44psi, who would ever need more?

 

It is very difficult if not impossible to fully control the boost on the VTGs, on my car i have different boost in every gear, i think the maximum i have noticed is 1,6 Bar in 4th gear

 

Totally untrue, difficulty in controlling boost has nothing to do with VTGs themselves. With proper aux unit one can have gear dependent boost with VGTs too. The problem is the lack of proper unit...

 

Thx for previous answer!!
Can you explain more here please?
I am interested in the plusses and minus's of using VTG--I have reasons to use them-- so trying to understand what is possible and impossible.
It is obviously easier to go other tried and true directions and knowing the comparatives is not so easy to follow.

 

I would like to hear a tuner explaining how the boost can be fully controled on VTGs , also Tom should explain the 1,9b on their 68mm :-)

 

With a unit that has gear dependant boost control and certain type of programmable output(s) it can be done. Problem here is that to get both of those features you'll (just now) need either Syvecs or ProEFI Pro128 (or similar unit) standalone...pretty expensive for just boost control. So far I haven't found any boost controller that has all required features for that.
In addition to that hardware you'd need a tune for Motronic that understands higher boost leves and disables certain VTG contol/feedback features (for not getting CELs).

I'm not a tuner (just a D-I-Yer ), but have electronically controlled VTG turbos in a 996 turbo engine (independent of ME7.8) and can set another one to 0.5 bar and another one to 1.5bar...just for example, no sense to do that though... My controller has dual programmable outputs and within the range of compressor map I can set a boost level I want. It's just can't do it gear dependent.

PS: IMO pneumatically controlled WGs are so last season...