Garrett PDF catalogue

[Jamo]

Any chance of redoing the graph using the 3076 compressor map?

[Jamo]

Turbine map.

[Jamo]

Take a look at this one I did last night. Its for a 2.5L stroker (sorry I don't know exact stroke) with a GT30R and GT35R in mind. These run quite close to the surge line... Note the increased VE required to make it work on GT35R.

Paul

This sheet i'm referring to

81.5 on a 95.5 stroke

Can anybody teach or point me to websites where I can learn to translate compressor maps?

[Flat on my back]

Come now Jamo, Motorgeeks. Think there is a thread in the turbo section called 'How to read a compessor map'.

Think the site might be down at the mo!

[Jamo]

Come now Jamo, Motorgeeks. Think there is a thread in the turbo section called 'How to read a compessor map'.

Think the site might be down at the mo!

Motorgeeks is down bud

[Jamo]

No-one?

[james_bufkin]

The lines on the turbine map are choke lines.
Anything under the choke line for a given hotside is possible. There are no surge lines.
Calculate corrected flow using the Garrett formulas and you will see where your turbine chokes.

Using the step increments between lines for different hotsides will tell you their respective influence on boost threshold. By comparing Choke Points, you can determine their effect on boost threshold when using the same compressor.

For instance, you might find the difference between choke lines equates to about a 500rpm difference in peak flow. This would mean each successive turbine step will introduce 500rpm lag but have more ultimate flow.

And since the Turbine is the Engine that drives the compressor, the obtained Pr from a certain flow is related to the compressor, (you carry that over). Notice how at a set flow, the Pr steadily increases, but flow does not. That is your Choke.

[quattro]

K26/27/30 (same spec as Doug's and Tom's) (up to 480 crank HP and 580-600Nm) Mihnea

How could i get my hands on such a turbo, i was thinking of going down the gt30R rout but after reading this my mind is made up im going to go with my origanal plan of a KKK hybrid, and allso the cost of such an iten would allso help.


. . . . . . Minhea, Doug or Tom where did you get your turbos form?

[james_bufkin]

Ive said this before on some other forums, but turbo selection for the I5 has been beat like a dead horse.

The only real twist on the matter is the recent BB turbos and what that actually does to boost threshold.

The nice part about the recent Garret Literature is that the compressor maps and turbine maps are very useful to predict behavior of older K27 and up turbos. This is so because the basic dimensions and construction of the actual compressor and turbine has not changed drastically. Aside from titanium compressor wheels which effects weight and strength. Anti-surge housings will help the compressor operate closer to the surge line with a loss of overall efficiency. And BB center sections have reduced internal friction which moves the response line to the left allowing the use of a larger hotside. Or more tendency towards Surge. Turbine and compressor choke lines remain unchanged from a BB to Journal bearing turbo.

Here is the nice part, for all things, there are comparables. Mostly because alot of the Garrett line has direct close equivelants to KKK products (dimensionallY).
So you have a family of compressor wheels that are 2.4, 2.6, 2.7, 3.0, 3.2 and 3.4 inches in diameter. (60mm, 67mm, 71mm, 76mm, 82mm, 88mm) Those are the ones that you can get on Garrets and KKKs. The KKK wheels are in inches and the Garretts are in millimeters, but Notice the similarities in sizes?

K29=GT35R or GT40, K27=GT30R, K28=Gt32, GT2871=RS2+, GT2867=RS2, k24=Gt2860

For instance, the K29 Pikes Peak turbos I have, K29 compressor with 3.4" wheel. #9 K27 hotside. This would equate very closely to a GT4088R (within a mm or so). Audi would not often use a hotside smaller than a #9. And the IMSA and 90 cars used even larger K29 turbos in the GT42 and GT45 range.

So all that being said, yes the Garrett BBs are excellent center sections. There aren't many cons to the BB center section aside from durability. Oil restriction and Controls that prevent turbo surging are important for the bearing's life. Its important not to surge a BB turbo. Surging can be from undersizing the turbo or improper BPV or BOV controls. Gas Mileage is also a concern as BB turbos can actually produce too much boost when its not needed at low cruising RpMs (i.e. you might get 4-5 lbs of boost just rolling down the highway, which will kill your mileage).

I run a Garrett Gt35R on my Ford F250 Diesel. And a K27#7/K29 hybrid on my rally car wihout BPV or BOV. If it weren't for the fact that I like the KKK for the car, I'd run a GT3582R or GT4088R with a Blow off Valve. And you don't need to use a small hotside with a Garrett BB turbo.