Let's do Math...:) - BMW Forum

j123crx · 10-13-2005, 07:20 PM

ok, my maunal says my 85 318i 1.8L has 108 horsepower and weighs 2395 pounds with a full tank of gas.

so...

if i take off 150 pounds of weight off and you get 1HP for every 6 pounds.

+25HP

another 50 pounds off for only filling to a half tank of fuel (1 gallon=6 pounds), vehicle weight now only 2345.

+8HP

no muffler AND cone filter intake.

+10HP

so my HP is now............151 Horsepower ?

does that sound right to you ?

Kowalski · 10-13-2005, 07:35 PM

no, that would be power to weight ratio not hp... but yes it would simulate those gains. assuming you did the math right... and i really dont feel up to doing any more math today specialy after my mid term...

ldsbeaker · 10-13-2005, 08:43 PM

I agree, that would only increase your power to weight ratio.
If I remember correctly, the hp formula has to do with your torque and the rpm's. Taking weight away will not increase your horsepower, it only makes the power you have work a little easier.

DJProfessor · 10-14-2005, 03:07 PM

upping the power to weight ratio can be your ace in the hole. our old air cooled dubs had like 100 to 1 (or more, can't remember).....the V8 guys use to laugh at us when we told them we were getting a rocking 222 hp out of our stroker motors.....they weren't laughing after we ran much lower et's than them.

filter27e · 10-14-2005, 09:54 PM

Well for an extreme comparison, a Harley has in the vicinity of 60-80hp depending on size, but weighs between 500-800 lbs + rider. Then you have sport bikes which can have around 120hp and only weigh around 400lbs + rider. Pretty quick aren't they? So no you're not really increasing your HP by decreasing your weight just the ratio, UNLESS you're talking about decreasing the weight of drivetrain components and increasing BHP then yeah that's correct.