Sorting out some old papers I found some notes I made on power outputs. See below :

BRAKE HORSE POWER

25 Bugatti 8 valve 1327cc
30 Bugatti 16 valve 1453cc
40 Bugatti Brescia 1496cc 69 x 100mm.
49 Bugatti 37 1500cc on petrol @ 4,200 rpm
56 Bugatti 36 1100cc with Cozette s/c on 80% Benzol @ 6,250 rpm (Factory).
64 Bugatti 37A 1500cc on petrol @ 4,500 rpm (Factory).
71 Bugatti 39 1500cc on petrol @ 6.000 rpm (Factory). 8 cyl.
80 Bugatti 36 1100cc with Cozette s/c on Elcosine @ 6,250 rpm (Factory).
100 Bugatti 18 5027cc100x160mm
123 Bugatti 35B on petrol / benzol mix. (Factory)
125 Bugatti 39A
126 Bugatti 39C 1500cc s/c 8 cyl 52 x 88mm @ 6,200 (Factory).
128 Bugatti 43 s/c on petrol / benzol mix @ 5,000 rpm
135 Bugatti 57 3300cc on petrol (Factory).
135 Bugatti 101 3257cc on petrol with a twin choke Weber car @ 5500 rpm
147 Bugatti 35B @ 5,200 rpm on Elcosine (Factory)
148 Gough Frazer Nash. 1496cc. 2 s/c at 16 psi. 2 SU carbs. T. Doman Chief Engineer.
151 Gough Frazer Nash. 1496cc.2 s/c at 23 psi. 5250 rpm 2 SU carbs. (Post war)..
154 Bugatti 51A @ ? on Elcosine (Factory).
158 Bugatti 35C @ 5,500 rpm on Elcosine (Factory).
165 Bugatti 57C s/c on petrol (Factory).
185 Bugatti 51 2300cc s/c on Elcosine
188 Bugatti 101C s/c on petrol with a 3 psi boost @ 5,200 revs.
200 Bugatti 46S tourer @ 4,000rpm
200 Miller 1500cc track car
200 Bugatti type 57G with standard 57C 3300cc engine (on Benzol mix ?) Le Mans ‘Tank’ (source Jean Bugatti).
250 Bugatti type 41 Royale. (H.G.Conway estimate)

420 Bugatti 24300cc 16 cyl. aero engine 110x160mm
462 Bugatti 50B in 1939. (Factory).

I have tried to only include figures from reliable sources.

This is most intriguing, the 1500cc Miller produce 200 BHP while the most powerful Bugatti 1500, the T51A, can only muster 154 (factory claim). Let us also remember that the factory claimed a 125 mph top speed for the Royale! Another thing, was the Frazer Nash not significantly cheaper than the equivalent Bugatti? Yet Bugattis are now more revered than either marque. I wonder how much of this is due to the ravishing beauty of Ettore's racers?

Johan

I would like to expand this list.

Any other figures (with as much detail as possibleas to source of info.) would be most welcome.

For some reason this list intrigues the heck out of me, and now that I am home I suddenly realised why; my first Bugatti book was Conway's Great Marques series, and he provided a box with dimensions and specifications for each model. The differences are fascinating, for instance : T46S - the above list gives 200bhp, Conway - 160 (and 140 for the unsupercharged version), but for the T50 Conway states 225, while the above list gives 462 for the T50B engine by 1939, which does give credence to the rumour that Jean Bugatti hid a completely new racing engine from his father by claiming it to be a development of the T50.

I see that a supercharged T51 produces 185 on Elcosine (Conway 160-180, no fuel mentioned.) while a T35B on a petrol/benzol mix musters 123. (Conway 130-150, again no mention of fuel) As a matter of interest, there are some very rapid T35's racing today, how much would they produce?

Conway gives an output of 250 for the T59. How much did the Alfa Romeo Tipo B / P3 deliver? I am quite prepared to believe that the Alfa was the more successful racer, but surely the T59 was the more beautiful? Perhaps possessed of even greater beauty than the immortal T35. Perhaps. But the T35, unlike its bigger sibling, was a very successful racer.

My sincere thanks to the Gentleman from Wales, I love it when I have these little arguments and debates going on in my brain.

Regards
Johan

Geraint Owen was aiming for over 200bhp with his 35B with a special Dutton pressure-fed crank allowing higher revs than standard, modified supercharger running at higer than standard speed, SU carb (I think) and a modified cylinder head.

All the quick GP Bugattis racing today are giving more BHP than when they left Molsheim and the old UK hill-climb venues have surfaces which bear no resemblance to those used in the twenties and thirties. This enables the new breed of Bugatti drivers to mouth-off in the beer tent that they have beaten the times set by Raymond Mays or Wimille.

A well prepared 35C (standard rollerbearing crank) with the Molsheim option 1.22 blower drive gearing, standard 48K carb. properly set for methanol mix and .9 to .95 bar blower pressure gives 200bhp @6000.
The Dean T51 is estimated at about 240 bhp.
Bugwrench

Okay, I'll respond with a question : A 250bhp T51 will be quicker than one putting 185 on the tarmac, but will the owner of the more powerful car get more satisfaction/enjoyment than his slower rival?

If the owner is a racer (who also happens to love beautiful old racing cars) the answer is yes.
If he is NOT a racer he will wet his pants.
Bugwrench

Good answer! I hear through the grapevine that you have some racing experience of your own. May I assume you love "beautiful old racing cars" too?

Regards
Johan

Hunter, you should be careful what you believe when you hang around the beer tent! Some slower car/driver combinations will always use wild exagerations to make up for their own performance shortcomings. After all it is easier to point the finger and say so and so is only faster because they have done this and that, than it is to say they are faster because I am a hopeless driver who cant drive sheep through a gate.

It is true that I have aimed for around 200bhp. But there are no cylinder head modifications (in fact I am using small valves not big ones) and I am using the Molshiem 1.22:1 blower drive ratio on a standard blower. The issue of the pressure fed cracks improving perfomance is overstated by the slower folk I mentioned above.

The constraint on a GP Bugatti engine power output is in the blower inlet not the crankshaft. You can only burn as much oxegen as goes in that hole. This is why a 2000cc 35C develops as much power as a 2300cc 35B. More revs isnt more power, becasue you dont get any more oxygen into the blower, so you cant burn any more fuel. It is just he 35B will have more mid-range torque. At 3500rpm, the 35B is sucking in more oxygen that the 35C - hence the increase in torque. Bugwrench's figures look spot on to me. 6000rpm/200bhp for a 35C, but at around 5250 for a 35B

Other folk have tried 1.4:1 blower drive ratio and found that the engine power peaks at 4500rpm (it is that much air going through the hole).

Now you could run 1:1 gears and then rev to about 7200rpm, but the pumping losses and the manifolds would mean you would be worse off, plus the piston speed would be getting really high.

In the old car world there is a strange belief that all racing cars were the same when they were raced in period. This clearly wasnt the case. The works cars had lots of better bits, better fitting etc etc that you wouldnt get as a customer.

All that said, your point about improved road surfaces and better tyres is well made. It is easier today to be as quick as they were in their day. That said though, in period, spares were not a problem so you could blow an engine up today knowing another was available from the works off the shelf. Although then and now, only if you could afford it.

Another Bugatti owner joined! Thank you. For all those deeply fortunate individuals who use and/or race their cars, I wish to raise a subject, but my own thoughts are so garbled that I am afraid I am going to ramble on a bit. It's that whole using vs. preservation philosophy thing that's got me going , herewith some random thoughts, observations plus a few things I've read :

Owner of a very original sports racing car refusing to race at Goodwood because he does not want his car humiliated by hot-rod D-Types. Fangio telling the owner of a 250F that he used 11 000 revs during a race, but had a new engine for each ; owner telling Fangio he uses only 9000 because he has only one engine. ERA R4D - without comment. Should the Williams Monaco winning T35 be raced? Is a car mothballed in a museum still alive? What purpose does such a car serve? How is that different from the raced one? What can be done to improve the reliability of an old engine? What can be done to improve the performance of an old engine? What should never be done to improve either? Finally, and this one is specifically for those who race their own cars both hard and frequently : What is the difference between racing and vandalism? (I'm not being facetious, I am talking about your own approach, or philosophy if you like ; is there a line you will not cross in the pursuit of a faster time?)

Now I've confused myself even more, so feel free not to respond. But I'm really damn curious to hear how love of Bugatti manifests itself.

Thanks
Johan Buchner

Johan (et all), I will start a new thread on "driving vs perservation". I will copy your posting to the new thread, you made some good points I would like to dig out.

Enjoy:
http://www.bugattibuilder.com/forum/viewtopic.php?p=4560#4560

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Vive la Marque !!