Close up on BMW F1 turbo engines and Brabham BT52

[benjabulle]

Hello, first part of a report on BMW F1 cars with BMW F1 turbo engines ( the most powerful in the history of Formula 1) and Brabham BT52. That's here, enjoy :
http://www.gurneyflap.com/focusbmw.html

[riff_raff]

benjabulle,

The Brabham BT52 with the "laydown" BMW engine was a great engineering concept. However, it's my understanding that it did not perform as promised because the engine had an oil scavenge problem and thus suffered severe crankshaft windage losses. Oil would accumulate within the low ground clearance sump and could not be removed, due to the direction of the crank rotation and the position of the oil scavenge pump pick-ups. A crank/rod assembly trying to pass through a slug of oil gets slowed down significantly. Thus the engine had very poor throttle response.

When the engine was converted to a more upright installation, it performed much better.

[benjabulle]

benjabulle,

The Brabham BT52 with the "laydown" BMW engine was a great engineering concept. However, it's my understanding that it did not perform as promised because the engine had an oil scavenge problem and thus suffered severe crankshaft windage losses. Oil would accumulate within the low ground clearance sump and could not be removed, due to the direction of the crank rotation and the position of the oil scavenge pump pick-ups. A crank/rod assembly trying to pass through a slug of oil gets slowed down significantly. Thus the engine had very poor throttle response.

When the engine was converted to a more upright installation, it performed much better.

The laydown engine was run in the BT55 and BT56. According to BMW, the engine didn't have a scavenge problem, and, on the bench, it performed exactly the same as the upright engine. But Gordon Murray reported this kind of scavenge problem and the fact that the engine couldn't accelerate as fast. The BT55 had a big problem of traction, which didn't help, but the laydown engine could "only" get 4,9 bar as 5,5 bar were possible with the upright one, so....

[West]

riff raff what imsa car did u work on?

[riff_raff]

West-

Did engine/transaxle design for Electromotive/NPTI from 1988 to 1990.

[West]

Cool

I'll assume you either worked on the Nissan P35 or R90CK or CP.

[riff_raff]

West-

The IMSA P cars we ran in '88 and '89 were Lola tubs and Electramotive body work. The engines were single turbo SOHC VG30 based designs. They ran at the 2100 lb weight limit with the IMSA spec underbody and turbo restrictor.

The '90 car was an aluminum honeycomb tub and suspension designed by Trevor Harris with NPTI bodywork. We had a 20% scale windtunnel in house. The engine was a twin turbo DOHC 3.0L V6 and the transaxel was Hewland VGC200 guts in an NPTI housing. It ran at the 2100 lb weight limit with IMSA spec underwing and turbo restrictors.

I left before the P35 car was finished, but I think it was designed to run under the IMSA rules for group C cars.

The twin turbo engine I worked on was actually quite interesting. If you can believe it, it used production head castings. The crankshaft and block were custom made, but for whatever reason (marketing?) we were told to maintain the 60 deg vee angle and split-pin crank design of the production Z engine. For this reason, the cranks were very unreliable at long race distances.

[benjabulle]

I posted a focus on the ZAKSPEED 871 turbo and its engine. http://www.gurneyflap.com/
You can compare the datas with the BMW engines and see that in 1987 they had about the same power.

[Guest]

added photos and technical datas on Renault turbo EF15, engine that allowed Senna to take so many Pole positions in 1986.
http://www.gurneyflap.com/renaultef15.html