Someone in another thread said I should post a link to this as they found it interesting and thought some other people on here would too, its a reply I made on vauxsport to a guy who was asking about how you interpret compressor maps, and ive tried to write it in a way thats simple to understand for people with little or not experience of turbo compressor maps, and its fairly well illustrated with graph examples and how you read them etc.


http://www.vauxhallsportforum.com/ph...urbos-t92.html

 

excellent chip now i fully understand what goes on well explained

 

Awesome chip

Very good read mate

 

Spot on it not really that difficult to understand but it still doesnt help me in deciding what turbo will suit my spec best.

Any advice i'm after around 350 400bhp mark in a 1.8 20vt vag motor.

I've heard people use the gt28rs but there on there arse at 400bhp apparently and there is a load of different spec gt28's

 

Yeah the GT28RS would cope with the bottom end of that.

2871 would manage a little better.


Personally i would just use a T34 probably, despite it not being trendy and ball bearing etc, cheap, strong, easy to rebuild, cheap to get parts for.
And best of all, can easily be converted to a UT38 if you need it later on.

 

http://www.turbobygarrett.com/turbob...ch_center.html

This is also a very good read. As for what turbo if you understand the compressor maps you should be able to determine what spec turbo.

http://www.turbobygarrett.com/turbob...ochargers.html

Here is the entire Garrett range with compressor maps just have a look through them

 

'trim' isn't the angle of the blades Chip...... NOT trying to pick faults, but that's as bad as 'wastegate chatter'

 

It is the angle mate, indirectly, as Trim is the difference between the inner and outer circle diameters and thats what determines the angle on the blades, so thats what you see when you look at it.

But yes you are correct that a more accurate explanation would have been to mention the inducer and exducer areas

 

This is the diagram off that Garrett website with regards to trim

 

Never thought of a t34 with .63 exhaut housing i take it you mean, thats what i used on my old cossie and liked it cause it used to build the boost up rather than be punchy like my old t3.

Whats the pros and cons of the same spec gt series turbo over the t34 though cause i dont mind spending the cash to get a good spec well usable motor. O and i'm looking t external wastegates to

 

The T34 will be laggier than the GT2871 or similar.

So the GT is kind of "better" from that respect, but i just like the toughness of T series turbos.

You wont really need an external gate, but if you want to be too noisey for tracks feel free, lol

 

Edited by me - as Chip pm'ed me as usual,what a fucking snitch .
Mike R

 

Thats the one, from that you can see what i meant about the "angle of the blade" varying as the diameter changes

 

I know what you meant Chip, but it's not like a .xx trim has a 45 degree angle, and so on, was just clarifying for others before it turned up on Top Gear

 

APMSLOL .

 

I like the idea of being able to work out what my tubby is capable of but I cant find a map

Pulsar GTi-R:
T-28, 60 trim 60 mm BCI-1 compressor in standard T-3
housing. 79 trim 53.8mm Inco T-250 turbine wheel .86
A/R turbine housing.

 

AROFLMFAO