Turbo Boost

[PS]

Hi guys,


I have a question for the turbo guys here. Can any one tell me how much boost you run with your turbos? I would just like to have an idea as to how much of an effect the restrictor has on the boost of the turbos.

Peter

[PS]

Hi guys,


I have a question for the turbo guys here. Can any one tell me how much boost you run with your turbos? I would just like to have an idea as to how much of an effect the restrictor has on the boost of the turbos.

Peter

[Patrick W. Crane]

I'm thinking about running a turbo next year or possibly the year after, and have found out several things.

1. If you look at the power curves for FSAE restricted engines, the power band levels off all of a sudden as the pressure on the inside of the restrictor becomes essentially zero (vacuum). As the turbo has to be located on the down side of the restrictor, it can not pull air through the restrictor any faster than a non turbo at high RPM.

2. What it can do is pull more air through at lower rpm when the NA engine is still breathing easy. This should allow for a low down torque gain that is quite substantial.

3. As the revs get higher and higher the benefits become less and less, eventually becoming detrimental to your power as all the turbo is doing at high RPM is clogging your exhaust.

4. Turbos add weight, and on such light cars, the weight is significant

5. Motorcycle engines are very high compression already, and with the addition of a turbo, the compression effect jumps very quickly. If you are going to run much boost at all, you might want to think about lowering the compression ratio.

6. Turbos use not only the push of exhaust, but the thermal expansion of gases to create the energy needed to spin the turbine wheel. This makes them much more efficient than superchargers which run directly off the crank.

What all of this means is that as you approach the cross over point of usefulness, you will be running as much boost as physically possible.

Not sure if that tells you anything you didn't already know, but there it is anyway. If you do get a turbo running i would be very interested in talking with you further and exchanging ideas and info. All i have right now is a bunch of ideas and some books. You can reach me by email at uvic_racing@hotmail.com

Cheers

-Winston

[Doggyollie]

We are still messing around with our 2002 car and we have about 11.5lbs of boost.


Ian Bennett
University of Arizona