Thread: The truth about horsepower

Quote: Originally Posted by brettmcc Yes, hence why the Veyron was billed as 1000+hp in NA, but wasn't in Europe. Metric horsepower, as a rule, is defined as 0.73549875 kW, or roughly 98.6% of mechanical horsepower. This was a minor issue in the days when measurement systems varied widely and engines produced less power, but has become a major sticking point today. Exotic cars from Europe like the McLaren F1 and Bugatti Veyron are often...

Quote: Originally Posted by Mike Drew With respect to gearing: Note that the actual gear ratios in the Gulf car listed above are very, very short. Fourth gear is 1:1 and fifth is only .81 overdrive. In a 'normal' ZF, third gear is 1.04, fourth is .846 and fifth is .705. Multiplying the gear ratio times the final drive ratio gives you the effective final drive. For the top gear comparison, you get this: 3.20 x .81 = 2.592 3.77 x .705...

Gulf/Jwa had 4th gears with ratios of; 1/1 or 0.96/1 and 5th gears of 0.78/1, 0.81/1, 0.85/1, 0.92/1. 3.2/1 R&P or CWP were used with the 0.81/1 (5th) gearing to break 200mph ( 205 ) on a 302 with GW heads. Same as using a 2.592/1 Diff ratio with a 1/1 top gear in a normal car. When you consider Nascar stuff is turning between 8000/9000 on a 355ci to reach similar speeds they were not doing to bad

Here's a contemporary photo of the F5000 car Mr. Kitchener told me the engine came out of. The caption calls it a 4.7 Shelby engine. The ZF has the combo speedometer drive/oil pump on the left side. Didn't mean to divert the thread and I apologize for the drift, CESLAW.

Quote: Originally Posted by Malcolm And is there a difference between USA bhp and UK bhp? Size - Ponys to Shires... . . . . . . just kiddin' fella's - don't bite too hard...

Re: The truth about horsepower More thread drift: I think this is interesting as a lot of GT40s and Cobras have way too much engine in them IMHO. Of course it's owner's choice, but you can scare yourself in a soapbox derby car if you can find a steep enough hill. Maybe a year from now I'll be wishing I had built a more powerful engine, but for now 360hp seems enough, especially with a 4.22:1 final drive ratio....

Sorry for responding to Malcolm's question, maybe I was being too quick in reading and missed something (like maybe some sarcasm that I didn't spot). Now onto another point, and apologies for the thread drift. What exactly caused that response from you? What have I done to offend you at some point? I would normally PM this, but its not the first time you've done this to me (i.e. responded with such short shrift and, in my...

Quote: Originally Posted by iank2112 Finally, yes, to some degree, HP measured in the 60's and 70's seems to be somewhat different than as measured now. It seems that the numbers from the 60's and 70's should be increased somewhat. Absolutely it was different, as stated in JimmyMac's post just below. Increased? No. The gross ratings from the 60s and early 70 (to 72) were quite grossly over estimated due to the testing...

With respect to gearing: Note that the actual gear ratios in the Gulf car listed above are very, very short. Fourth gear is 1:1 and fifth is only .81 overdrive. In a 'normal' ZF, third gear is 1.04, fourth is .846 and fifth is .705. Multiplying the gear ratio times the final drive ratio gives you the effective final drive. For the top gear comparison, you get this: 3.20 x .81 = 2.592 3.77 x .705 = 2.657 So the difference isn't...

No matter what you may read, the correct horsepower rating for any individual is "enough" to satisfy that individual... Some more than others.