which turbo to use? fast road

[davefox]

i know this is prob the life long question, but ive had a little search and its hard not to come up with millions of threads but basicly im looking for abit of more power than the standard turbo. The car is for fast road use and just abit of weekend excitement.

Spec is as follows,
Alloy rad
Double capcity intercooler
ktec manifold
2.5 inch downpipe and exhaust system
silicone hoses
seprate oil cooler
big air filter
cgb head
standard internals

now im not after huge huge figures i would be happy with around about the 180bhp marker.

after a t2/25 dont tbh i dont have a clue what i should buy or where from?

so if anyone can recommand a turbo or a supplier of good spec units that would be a great help.

Cheers Dave

[Mart]

For fast road/country lane use, imho, you can't beat the o.e T2 blower.

With supporting mod's, which you seemingly have, and a fair boost level, you should be able to squeeze near 180hp anyway.

[Big Jim]

My answer is always VNT. With the right actuator setup, more power AND less lag, where's the downside?

[Spooky]

My answer is always VNT. With the right actuator setup, more power AND less lag, where's the downside?

Hmm, VNT...

[Spooky]

What would I need then to bolt a VNT on and get it set up correctly ?

More importantly, what do they go for these days ?

[philr5t]

mine was 950 new

[Spooky]

...shizer...

Bit more than I expected.

[Big Jim]

Sounds a lot, but you do get what you pay for.

[rich-hgtt]

mine was 950 new

Where did you get it from Phil?

[Mart]

My answer is always VNT. With the right actuator setup, more power AND less lag, where's the downside?

Cost.

[5teve L]

T2/25 Ftw

[James5]

Sounds a lot, but you do get what you pay for.

I have to agree had a VNT on my last C1J and loved the feel of it the spool of a T2 and the power of a T3. I also loved the fact that you could adjust the vanes to what rpm you are wanting it to boost @.

[Spooky]

Well, I love the delivery of my turbo now, taken a bit of time to get used to it although I know the cam I have for it would make it even more awesome.

I've always had a soft spot for a VNT.

Is there a one size fits all because of how flexible the type of turbo it is or is there still a classification if you will i.e t2...t2/t25...t28 etc

The reason I ask is, I'm never going pay 950 for a turbo, even if it sucked me off

[James5]

Well, I love the delivery of my turbo now, taken a bit of time to get used to it although I know the cam I have for it would make it even more awesome.

I've always had a soft spot for a VNT.

Is there a one size fits all because of how flexible the type of turbo it is or is there still a classification if you will i.e t2...t2/t25...t28 etc

The reason I ask is, I'm never going pay 950 for a turbo, even if it sucked me off

Spooky pm for you

[Spooky]

Hang on J, I was pissing about in my user control settings the other day, let me go see what I've cocked up

[Spooky]

PM for ya J

[Frix]

Spooky if you want some info with ref to a direct fit VNT alternative drop me a pm as for some reason I cannot pm you

can you share it with the rest of us!?

[davefox]

ok well i may sound very thick now but what is the VNT? im new to all this so be gental

tbh cost isnt a problem, i will just wait till ive got the money for the turbo then buy it

Mart you reckon a T2 could produce that much power? but surely running the T2 this high would be over running the turbo? Im wondering wether i should buy someonething lets say is meant to run around 200bhp marker or "x" amount of boost then under run it slighty as to pro long the life of the turbo make sense?

LOL IM A NOOB :P

[Gymnast]

The T2 can definitely produce 180bhp but it will be reaching the peak of it's efficiency.

VNT is a different type of turbo, I believe first produced on diesel cars. Adam L is the turbo guru on here and he works for a company that used to make the VNTs ... last I heard they had stopped making them. The advantage of the VNT is it's a large turbo with very little lag.

[Big Jim]

Cost.

point taken

VNT stands for Variable Nozzle Turbine. Uses vanes in the exhaust housing to change the speed and angle the exhaust gas hits the turbine wheel, effectively changing the A/R of the housing, so you get the lag of a small A/R with the power of a big one.

They were first used on diesels although Porsche now use them, albeit with high specced turbine material that costs a fortune. They can be a bit sensitive to actuators which is why I developed my own actuator setup which gives low backpressure off boost and almost infinitely variable boost (sales pitch over!).

[Mart]

Mart you reckon a T2 could produce that much power? but surely running the T2 this high would be over running the turbo? Im wondering wether i should buy someonething lets say is meant to run around 200bhp marker or "x" amount of boost then under run it slighty as to pro long the life of the turbo make sense?

LOL IM A NOOB :P

It'll be pretty much on the limit, but it should still be the safe side of the choke line.

If you believe RR graphs, I achieved 170hp & over 200lbs/ft @ 1bar map on a T2 unit. A few psi more though, and the wheel would be supersonic, hence at that stage you're potentially running into durability & reliability issues.

Bar VNT, any turbo 'larger' than o.e will naturally introduce lag into the equation, which, for me anyway, takes the fun out of driving a gtt on the roads.

[davefox]

It'll be pretty much on the limit, but it should still be the safe side of the choke line.

If you believe RR graphs, I achieved 170hp & over 200lbs/ft @ 1bar map on a T2 unit. A few psi more though, and the wheel would be supersonic, hence at that stage you're potentially running into durability & reliability issues.

Bar VNT, any turbo 'larger' than o.e will naturally introduce lag into the equation, which, for me anyway, takes the fun out of driving a gtt on the roads.

thats a far point, i was looking at getting one of these "t25 front & core, .47 t2 rear, 55 trim comp wheel" which steve l recommands and offers a supplier for, but there is so much choice lol and of course everyone slates everyone elses and says o ours is the best! lol typical but everyone does it.

only reason i mainly posted on here was for peoples views as in yes ok you might need a t2/25 and ive had this unit from so on and im happy with it etc etc.

But i may just bolt standard T2 ive got back on and run it see how its goes..... now with standard turbo but all these breathing mods is it worth a rejet?

like i said im a noob when it comes to turbos and carb, first carb car ive ever owned always been electronic

[bigbadboytank]

New poster! (less than 10 posts)

I had a VNT on my last car, a total nightmare to set up right, however when you get it right they are very good.

however, after 2 engine rebuilds, i gave up, T25 all the way for me.

[Big Jim]

I refer you to my previous post...

[TNT ANDY]

I refer you to my previous post...

Go on then big Jim

[jesus in the seat of a 5]

right,Lets all go down jim`s` place and purchase vnt`s` and get him to set them up...

[philr5t]

i already have

[Big Jim]

right,Lets all go down jim`s` place and purchase vnt`s` and get him to set them up...

Feel free!