Need help with turbo selection.....

[Big P]

Well, I have done some homework on how to read and understand turbo compressor maps but I still have some issues. I figured out all my data, corrected CFM per RPM, boost pressure values, converted all that stuff to lbs/min flow ratings, etc. So far, I have only come up with 2 turbos that are anything remotely close to what I want, the T3 60 and the T3 Super 60. I graphed out everything on the compresser maps that I found on the net The highest boost pressure that I can run while keeping the turbo in some kind of efficiency is around 18 PSI. This won't do! For street driving, it will be fine, I'll probably end up running about 15-17PSI but when I take it to the track I want to run full out 25 PSI. However, the situation that I will be running into is the fact that at 25 PSI the efficiency is crap, and once I start to get to about roughly 5000 RPM the number goes off the chart and won't do any good(too much heat buildup). Selecting a bigger turbo and comparing the turbo map so that at 25 PSI @ 6000 RPM(my selected redline limit) it will have some type of efficiency, the spool up time will be tremendous. No boost until about 3500 RPM. That won't do either. So what am I to do? Am I going about this all wrong? The engine that I have is a 2.2L Any input would be most appreciated. Thanks for your time, Paul Moore

[kinkyllama]

I dont think you'll have much luck finding a turbo that is effecient at that kind of psi yet still spools on a street driven rpm level

[Big P]

I had posted the same question over on www.j-body.org, and one of the guys there told me to use a ball bearing turbo instead. Supposedly the ball bearing turbo has a higher effeciency at higer boost pressures. If I can definitely find out that I can have the same spool up time and better high boost efficiency, then I might just go ball bearing.

[Big P]

Well, I think that I might have found one that will work. It is a Garrett GT30R model. Let's see if the map will load....


Now, once I use this same map and plot in what my boost pressures should be at the 3000, 4000, 5000, and 6000 RPM intervals would be, I come up with this....

http://www.daewootech.com/forum/album_p ... ic_id=1306

So even though it doesn't start making boost until just at 3000 RPM, it has some efficiency all the way up to redline.

[Stefan]

A hybrid would be good for the 2.2 and cheaper than the new GT series. Try the following spec.

TO4E 50 trim Compressor
0.48 A/R stage II turbine

You can get these from Turbonetics. The 50 trim map is very good for a 2.2 8v or 16v. A lot of the Dodge turbo and Ford Pinto turbo guys use them.

I've seen one used on a 2.0 OHC too. Boost on that came on around 3000rpm. Would be sooner with the 16v head.

Glad to hear your project is still going well.

Stef

[Big P]

Thanks, I'm just trying to get everything in order before I start ordering parts. I'd rather take the time now so that the install will be that much smoother. I plotted out my same RPM points on the TO4E compressor map, and found them to be almost identical with the only difference being that the GT30R is closer to the highest efficiency range at 6000 RPM. Plus, if I were to rev the engne to 6500 RPM with the GT30R,then it would be in the 78% efficiency zone. Plus, the GT30 is a ball bearing style turbo. I'm not so sure about the TO4E, are they a ball bearing style as well? If so, then I guess price would be the major factor in my choosing.

[Stefan]

Turbonetics offer the TO4E/T3 hybrid with a ball bearing centre cartridge if required. But, I suggested it mainly because it pretty much fits the bill and the standard turbo uses journal bearings making it quite a bit cheaper than the GT30. Also, when it comes to the time to rebuild the turbo the journal bearing unit will be cheaper to rebuild.

If however, you have the budget for the GT30, it's better efficiency and quicker spool-up make it the best option.

Stef