Air starter pressure

[Scooter B]

Does anybody remember what pressure did the Buick Indy lights air starters use to start engine?

[Pop Chevy]

Use a nitrogen bottle. I would keep increasing press till the engine turns over. I THINK it was around 200 lbs.

[Scooter B]

Thank you.

[true racer]

Nitrogen pressure depends on the engine. The Cosworths (DFV and DFX) will usually work around 200 psi. The Buicks, because of the larger displacement, will need a little more. Just make sure the regulator on the bottle is a high flow unit and not just a welding supply store type. Also make sure that it is working properly and that the hose is rated for at least 300 psi. The Goodyear yellow hose is the one most of the F1 guys use.

Robert Metcalf

[R. Pare]

Been a long time, but if I remember correctly, the Indy Lights Buick used something like 1000-1500 psi.

[Scooter B]

Without plugs , I can spin engine easily with 200 psi. With plugs in, I have a hard time to even get it to move with 300-350 psi.


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[Daryl DeArman]

Wouldn't the air pressure required additionally depend greatly on the type and condition of the starter utilized? Vane vs Turbine for example.

I am ignorant of where these types of starters were originally sourced, and maybe their design doesn't vary. However, in the aircraft and diesel engine world I believe both types are utilized.

[B Reid]

The air starters I saw on the Buicks were vane type air motors, I believe made by Desoutter. They were not really special internally, they just ran on really high air (nitrogen) pressure 250 -300 psi as I recall. They did not last long since they were designed to run on 90 psi.

I was the product manager for Ingersoll-Rand's air motor division for a couple years. Since we were involved in Indy Lights, we looked at making a better version of the air starter but then the series switched to the Lola and electric starters. I might have most of the pieces of one of the prototypes here.

[R. Pare]

Yes, they were Desoutter. Vane type.

[R. Pare]

Looks like I was way off on the pressure. Checked with a friend who was a mechanic on those cars back then, and he remembers it being about 400- 450 psi.

[Charles Warner]

I was able to use 300 psi on the RT-24 (Judd CV) as well as the Cosworth DFZ 3.5 liter but I HAD to use a high volume regulator and 3/4" (IIRC) hose.

[Scooter B]

400-450 might work but I'll have to get bigger hose. The current hose tops out at 300 psi. The Buick I have is a little higher compression so I thought maybe that was the reason for not spinning fast enough.


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[B Reid]

You might want to check the condition of the starter itself. If there is a broken/worn vane, end plates worn or ridges in the cylinder you may be getting a lot of blow by in the motor and losing a lot of power there. Also there is a diminishing return in continually raising the air pressure. The ports within the motor can only pass so much and with the thermal expansion of the air or nitrogen you can freeze the motor.

[Scooter B]

Thanks, I didn't know if there was anything serviceable inside the starter or if I could get any more power out of it.


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