VNT technology comes to GT Turbos!

[Lowe]

A chap at RTOC who fiddles with turbos has managed to create a VNT turbo for the GTT. Typically used in diesels, these turbos are on the cutting edge of turbo technology and have been adopted by VAG and Renault on their current TD cars. Previously exhaust gas temperatures stopped such turbos from being used on petrol cars, however now with a bit of tinkering here and there it's been sorted...

What does this mean?

Well.. VNT turbos work in a way differently to normal turbos. Rather than having a wastegate which bleeds off boost to stop the turbo overspinning (i.e it limits how much boost it provides by leaking the excess gas), there are vanes in the exhaust housing. These are almost closed at low rpm and open up as more exhaust gases flow, therefore producing a quicker spool up and full boost earlier (i.e. it acts as an exhaust housing that changes size).



So in effect you have a turbo that spools quicker than a T2 yet provides the flow of a huge T3/4.

What does this mean for the little pushrod GTT?

20-70mph in 2 seconds on a standardish car with one of these turbos!

[Moby-Dick]

lumme......

I want one

[Atomic]

20-70mph in 2 seconds on a standardish car with one of these turbos!

WHAT! Now that is just mental!

[Lowe]

Indeed, remember this was speedo indicated mind so it's probably a little out.

To give you an idea about how quickly it spools, it provides 1.5 bar by 2800rpm.

Just sat revving the engine at standstill provides a whopping 1 bar. Usually with a conventional turbo a GTT won't even build boost at idle! Imagine the launches you'd be able to put down with one of these!

The only downside at the moment is the price and the lack of anyone knowing how long one of these turbos will last. Prices at the moment have yet to be announced but it's going to be ~£1000. That's a lot of money for something which might only last 4 months! Also, there's a slight niggle with boost limiting at the moment - it's possible in 4th and 5th gear for the car to overspool to something silly. Not good.. But, once these bugs are sorted out this is going to be amazing. Silly boost levels throughout the rev range means an awesomely quick little car!

[Rave]

What does this mean for the little pushrod GTT?

20-70mph in 2 seconds on a standardish car with one of these turbos!

I'll believe that when I see it, but >1g acceleration, yes please

Rich :¬)

[Lowe]

I'll believe that when I see it, but >1g acceleration, yes please

Rich :¬)

There's a video of it - alas it's on the RTOC website so I can't link you to it.

[[GSV]Trig]

So download it then u stick it on my website

[Lowe]

http://www.rtoc.org/library/file.asp?id=16188

^ Try that.

Isn't very clear but you give you an idea, the 12 o'clock position on a 5GTT is 80mph...

[Butuz]

Oooooohhhh... now i know what to get when my T28 dies

Butuz

[IainB]

Rah - that sounds interesting.
Wonder if its going to go more 'main stream' ?

[Zak33]

nice graphic Lowe....very good for explaining it...awesome principle.

[Lowe]

Rah - that sounds interesting.
Wonder if its going to go more 'main stream' ?

Already is in diesels, and it's not going to be too long before petrol versions become more popular.

This is the near enough the first of its kind for the GTT, but there are bolt on kits floating around for other cars. A couple of the hillclimb lot have been using them for a while and I'm told there's a few available in Stateside for various cars.

[Lead_Head]

"MY GODDD!!"

haha... awesome acceleration!

[streetster]

"this is the VNT on the test track"... looked pretty urban to me anymore vids lowe?

[Lowe]

http://www.rtoc.org/library/file.asp?id=16185

http://www.rtoc.org/library/file.asp?id=16186

http://www.rtoc.org/library/file.asp?id=16187

Few more vids, quality's a bit pants but better than nothing.

[Rob]

Thanks Lowe

I always wondered how the hell my "Variable Geometry Turbo" (as renault called it) worked.


Cheers mate, cracking graphic