365BB Vs. BB512 Horsepower

Its generally believed that the 365 Boxer produces about 20 more horsepower than the 512, at least I think it is and let's ignore the injected cars for now.

Why is that? Is the compression ratio higher or cam grind more radical? Or is it just since max horsepower is quoted at redline, and the 512 redlines 500 lower than the 365, that this is the difference? Does the additional capacity make up for some of this?

I understand the longer stroke and hence more lower range torque for the BB512 but was always curious about the horsepower issue.

Again, just curious.

Drew Altemara

 

The cam grind is more radical, the stroke is shorter and the final drive ratio is higher numerically. The redline being higher means the HP number will be higher but doesnt mean more performance. HP is a calculation from the measured torque so its a by-product really not what the engine is directly doing ( at least thats how I understand the readings). The other factor that effects the output or torque is intake runner length more than anything else. The 365 engine has a 5mm shorter stroke (1mm smaller bore) and lower compression than the 512 as well as less displacement. It makes its power through high rpm rather than from a lower rpm like the larger engines.

 

Exactly -- the only condition where a 365BB makes more HP than a 512BB (if it really does) is above ~6900 RPM based on the F published specs:

If a 365BB is making the rated 344 HP at 7000 RPM (redline), at 6900 RPM it would be making about ~334 HP.

The 512BB is rated 340 HP at 6200 RPM (redline = 6800 RPM and the power would be down here a bit).

(The published difference in stroke is actually 7mm, and, IMO, if the numbers are fudged, they fudged more on the older 365 numbers as the 14% difference in displacement is significant.)

 

CORRECT!

 

The factory wsm states 360hp DIN for the 512bb, the 365 prototype was 380 then the production car detuned to 360 but thats Italian hp and even Ferrari said it was overly generous the reality around 340

 

Someone here had a 512 carbed engine dynoed on an engine dyno which makes it impossible to compare to a chassis dyno number on a different car but at least it might indicate a real number. Carabou did the engine and the dyno and if memory serves me correctly, it was the one that had a sodium valve go for a tour through the piston and related components. I forget the numbers though as well I dont now if it was stock.

 

yeah thats the one 20K rebuild after that, it put out 360hp and was stock

 

I must have fat-fingered a calculator key -- I should've typed:

If a 365BB is making the rated 344 HP at 7000 RPM (redline), at 6900 RPM it would be making about ~339 HP.

 

the dyno sheet you refer to was/is the car that belongs to dopplemax. the motor was not totally stock and included je pistons, tubi headers and tubi exhaust.

and yes the valves did have an issue!!!

 

All that and he only made 360HP, interesting and thanks! I was looking for the thread but couldnt find it.

 

Newman how is the cam change comming.

 

Its not, the 308 is priority. I will do it though, I have to have a distributor adapter made up which I havent gotten around to yet. Too much on the go as usual.

 

512BB + cam = A better car in all categories. ( except for that consumingly important production number category )

 

And except in that consumingly important styling category. IMHO.


Onno

 

The early 365BB is the best of the series. Later versions may be more efficient but they quickly lost the purity of design the early BB exhibits. The solid color paint scheme was especially lacking.
CH

 

I was going to reply to the "the 365BB is the best of the series" statement but then I thought that a response was pointless. Ferrari owners are more likely than not successful people of influence and perhaps used to having their opinions taken as fact. Yes, yes very important people. However, on this forum we have a whole bunch of these opinionated - "often wrong but never in doubt" - people. Lots of threads are occupied with opinion that is presented as fact. Most of what we say should probably be prefaced with an IMO or something of that nature. Am sure Newman believes his BBi to be the best whereas Gene and Fastradio obviously prefer their 365BB's. Some think all Ferraris, except the F40 and 288GTO, are worthless after Fiat stepped in; whereas Porsche fanatics...well, they are Porsche fanatics. After saying the "365BB is the best," you should follow that up with "my daddy can beat up your daddy."

 

a good point. i think you and i would agree, that each of the versions are pretty cool!

 

I dont think mine is the best, I would like one of each myself and with a lot of luck that might happen one day but im not hoilding my breath! I love the benefits of fuel injection over carbs and there are advantages to it as well that cant be denied. There are times when i wish my car had carbs though, especially the cost of rebuilding the CIS components which I have to farm out due to lack of equipment. If it had carbs, I would do it myself in my basement. Its my preference thats all. Now what would really excite me is Lucas timing injection on my car!

 

Yes, they are all cool. Like all things, it's personal prefence and even your mood that day. Some days my '72 B is "the best" - in its own way. Other days, it's the stradale or the Evo. I choose the 512BBi for my boxer for a bunch of reasons but those are particular to me and my quirks.

 

didn't have Tubi exhaust just headers which do little, 360hp here's the link
http://www.carobu.com/html/512bbcarb1.html

here's another 512BB carb at 471HP with some mods, try that with CIS without forced induction ha-ha


http://www.carobu.com/html/512bbcarb1.html

 

You posted the same link twice. I'd really be interested in seeing what was done to get the 512 up to 471 HP though, if you can find the right link.

 

Try driving the 471hp one on the street, it would be frustrating to drive. Any injected car with a turbo would make more than that and be easy to drive! Ill take forced induction any day on any car. My truck has a roots type blower, the sound is amazing. Speaking of trucks, how would you like to get waxed by my pickup in your BB LMAO!

As for the headers, have you done any dyno testing or flow testing on the stock vs tubi headers? Didnt think so, try unwrapping your headers one day and look at the buggered up plumbing for number 6 and 7 cylinder, a kid could make better headers than that. Even my 365 headers suck compared to the tubis. Your forgetting its fresh and with modern pistons plus the headers and a dyno tune. Your old engine with factory compressor pistons wont pump out those numbers.

 

So are we generally agreed, that with in a few HP, this is just an issue of where HP is quoted and wiyh the 365 being higher reving generates more HP but the 512 having a longer stroke delivers more low end torque?

 

Yes thats correct, I would like to know what the real numbers are though rather than relying on ferrari's specs.

 

I'll get my "torqueless" 365 up on a chassis dyno in the Spring....Hopefully, their dyno can read "high enough"...LOL!

David