Saab T-25 compressor map

[elderc]

Hey Guys,
Can any of you guys read a compressor map ? This is the map for the small Garrett T-25 I'am running on my car.
I would like to know is what is the peak HP's you could run on this turbo and what would be the hightest boost you could run before your in the choke zone. At this point I'am running 10.5 psi. boost to redline 7,200 rpm. @ 219whp. 185tq..... motor is a 1.8

Thanks in advance

[CG10DET]

When does this come on boost? I am going to be running this turbo, is it the one on the Saab 9-3 and the NG900?

Also, do you have a larger version of the compressor Map?

[elderc]

Starts to spoil at 1,800 rpm full boost by 3,200 , sorry about the map size thats how I downloaded it, but you can resize it on you computer.
Saab 9000 A/R .48/.49 trim 55

[CG10DET]

I have a larger version of it.

Ok, I worked it out at an absolute maximum of being able to flow around 190bhp but you'll need a pressure ratio of 1.68

That's based on tuning to 11.5:1 and a BSFC of 0.55

[elderc]

I'am making 219whp which is over 250bhp @ 10.5 psi a/f 11.5 , thats way more than 190bhp ?

[CG10DET]

The Brake Specific Fuel Consumption can make a vast difference to the numbers, so without you being able to provide me with that info I can't get you anything else.

The other thing is that the turbo will still produce boost, but at the choke line it will become very restrictive where it will lost it's ability to flow air efficiently.

[elderc]

Thanks for the input, I guess it's fair to say the power level that I'am at is the limit of that size turbo ?

[CG10DET]

On a quick glance I would say yes, the calculations are covered in Garrett Turbo Tech 103

[Accord2nrz]

I can read them. I will take a look at it too this evening. Are you look for peak boost? or optimal boost for the specific design of the turbine. Those are two different numbers that will affect your tuning scenario.

[elderc]

Optimal boost , and thanks for checking! as it stands now I'am putting down 219whp @ 10.5 psi A/F's 11.5 to red line 7,000 rpm ( not to rich a/f's for mazda) but maybe to rich for others.

[mhamrick]

The T25 55 trim is the same as the Eclipse 2nd Gen T25. They max at around 20lb min. I know a guy that made 225whp with one on a 4AGZE so that is pretty damn good. I have seen this turbo listed online as a 45 trim but it is 55 trim.

I have this same turbo but I upgraded mine. I bought a T25 60 trim compressor (for about $20) and swapped it on. I had to get the compressor housing milled but I have done that. The difference should be quite noticeable once I have completed the install. The T25 60 trim flows around 25 lb min which is comparable to a T3 50 trim at 28 lb min.

It will be going in a 86 MR2 with a 4AGZE longblock.

[elderc]

mhamrick,
Thanks for the turbo information, so a T25 60 trim will be able to flow enough for 250 whp ? which is what I'am looking for. I'am @ 219 whp with the 55 trim Saab. ( I know its maxed out)

[mhamrick]

I can not say 100% that you can make250hp with it but I can tell you that it is possible. In the latest Super Street (I steal them from WalMart cause they are not worth buying) there is a 1989 240sx with a CA18DET running the stock T25 60 trim and it is making 220whp and 256lb/ft on 12psi so that in itself shows what the turbo is capable of.

A major benefit is that the T25 60 trim can be pushed to hgher psi levels then the 55 trim. Here is the compressor maps. I will even post the T3 50 trim just so you can see that it is comparable.

T25 55 trim:
http://www.not2fast.com/turbo/maps/t25_55_saab.gif

T25 60 trim:
http://www.not2fast.com/turbo/maps/t25_60_nissan.gif

T3 50 trim:
http://www.not2fast.com/turbo/maps/t3-50.gif

Here is the link to all the compressor maps if you want to check them out and compare. I will tell you that a 14B is actually bigger then a T3 50 trim and they can make some nice power. There have been guys run 10 second quarters with them on stock block 1st gen Eclipses.

http://www.not2fast.com/turbo/maps/