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bradc
19-03-2007, 10:45 AM
I got around to pulling apart a stock turbo last night, the Turbine wheel has an inducer size of 35mm, an exducer size of 40mm and an A/R of approx 0.35-.45 (difficult to measure)

The compressor has an inducer of 32mm, and an exducer of 45mm, approx A/R of 0.45.

These figures are quite close to this turbo http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT15/GT1544_454082_2.htm which is rated at 150hp by Garrett.

The most interesting thing I discovered was that the turbine side is only rated at 6.3lbs/min of airflow, and the compressor can stretch all the way to about 14lbs/min, but the efficient point is about 10lbs/min (at about 1 bar)

Compare this to a GT2860R http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2860R_707160_7.htm which is the model of turbo I'm considering going with, it flows 16lbs/min on the turbine side, but it is most efficient at about 17lbs/min on the compressor, and can stretch all the way up to 30lbs/min

If you compare the ratios, to me it sounds like our turbos are heavily limited by the turbine, which is further reinforced by the fact that my rebuilt and upgraded turbos haven't had the compressor wheel modified at all, but the turbine wheel has been completely re-done with different shaped blades and a larger inducer. This implies that the limitation is the turbine side.

Thoughts?

AllBeItMine
19-03-2007, 12:48 PM
twice as good works well ;-)

zentac
19-03-2007, 07:58 PM
I looked at the GT15 and GT28's when deciding what to do with mine... in the end went single turbo.

bradc
19-03-2007, 08:10 PM
Apart from the lack of space that you have in the FTO, and ignoring extra costs, would you prefer a pair of those GT2860R's I've linked to? The thing I like about them is that they can provide 1.5bar from 4200rpm to 7000rpm, with the size of our engines, I should be at about 300hp at 4200rpm and 500hp at 7000rpm. Also they can provide 1 bar at 3500rpm which is 200hp.

zentac
19-03-2007, 08:14 PM
I have to say I'm aiming for a little more than that out of this one.

bradc
19-03-2007, 08:17 PM
what is the exact Garrett model number you're running?

Gly
19-03-2007, 08:24 PM
its not a garret,
its a copy of one or similar to one?

CANDEE
19-03-2007, 09:18 PM
I think he mentioned that he is running the equivelent of a GT35... I could be wrong though..

Im considering converting over to a single TD06.. :)

zentac
19-03-2007, 10:26 PM
what is the exact Garrett model number you're running?

It is a genuine Garrett Its a GT287653R the spec is on here http://www.aet-turbos.co.uk/turbo_services.htm

Munta
20-03-2007, 01:00 AM
sounds interesting... will those turbos fit between firewall and engine... just wondering if they will be a easy replacement for our stock turbos. very keen. just dont have time to do the research on it.

bradc
20-03-2007, 01:27 AM
450hp isn't huge though, my pair are rated at more than that together. how does it spool?

Munta - nope, you will need to do lots and lots of work to get them in

zentac
20-03-2007, 08:27 AM
Im on full boost by 3500 rpm

bradc
20-03-2007, 09:31 AM
thats good to hear, I was aiming for 4500rpm, but it sounds like I might be able to get there a little sooner