3-Series (E21, E30)Chat relating to the BMW 3-Series from 1975-1983 and 1984-1991 line. Specific models: BMW 315, BMW 316, BMW 318, BMW 318i, BMW 320/4, BMW 320i, BMW 320/6, BMW 323i, BMW 320i. E30 Family models include: BMW 325e, BMW 325i, BMW 325is, BMW 325ix.
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i really wnat to add more power to my car i have an 86 325es its quick but i wnat more horses and torqe, so if anyone has any suggestens, like some cheep ways or i dunno anything would help. thanks guys
dylan
Let's start with the road test. In acceleration, the 325is is only SLIGHTLY slower than the M3. (Zero to 60 in 7.5 seconds compared to 7.1 for the M3. Quarter mile in 15.7 seconds at 88.5 MPH compared to 15.4 seconds at 91 MPH for the M3). AND THIS IS WITH A GEARING DISADVANTAGE !!! Yes, the 325is has a 3.73:1 ring-and-pinion ratio whereas the M3 has a 4.10:1.
Doing nothing other than putting a 4.10:1 differential in a 325is will instantly make it faster than a stock M3 except for top speed.
How is this possible, you may think, because the M3 has 192 horsepower compared to 168 for the 325is?
This is where people's thinking goes wrong about what makes a car fast:
It's not how much horsepower the engine makes; It's better explained by the power-to-weight ratio (the car's weight divided by the engine's horsepower). But since the M3 and the 325is weight about the same, that STILL doesn't explain how the 325is with 24 less horsepower can outrun the M3.
The answer is in the area under the power curve of the engines. You can't accelerate all the way from zero to whatever with the engine always at the peak power RPM... so the shape of that Horsepower vs. RPM graph determines how much power goes to the wheels in real-world acceleration runs. The six-banger power curve is fat while the M3 is more like a spike, typical of a peaky twin-cam four. The area under the power curve of the six-cylinder is greater than the area under the power curve of the four cylinder, for the total RPM range used in accelerating. That's why the 325is is faster when you give it the same gearing.
Let's start with the road test. In acceleration, the 325is is only SLIGHTLY slower than the M3. (Zero to 60 in 7.5 seconds compared to 7.1 for the M3. Quarter mile in 15.7 seconds at 88.5 MPH compared to 15.4 seconds at 91 MPH for the M3). AND THIS IS WITH A GEARING DISADVANTAGE !!! Yes, the 325is has a 3.73:1 ring-and-pinion ratio whereas the M3 has a 4.10:1.
Doing nothing other than putting a 4.10:1 differential in a 325is will instantly make it faster than a stock M3 except for top speed.
How is this possible, you may think, because the M3 has 192 horsepower compared to 168 for the 325is?
This is where people's thinking goes wrong about what makes a car fast:
It's not how much horsepower the engine makes; It's better explained by the power-to-weight ratio (the car's weight divided by the engine's horsepower). But since the M3 and the 325is weight about the same, that STILL doesn't explain how the 325is with 24 less horsepower can outrun the M3.
The answer is in the area under the power curve of the engines. You can't accelerate all the way from zero to whatever with the engine always at the peak power RPM... so the shape of that Horsepower vs. RPM graph determines how much power goes to the wheels in real-world acceleration runs. The six-banger power curve is fat while the M3 is more like a spike, typical of a peaky twin-cam four. The area under the power curve of the six-cylinder is greater than the area under the power curve of the four cylinder, for the total RPM range used in accelerating. That's why the 325is is faster when you give it the same gearing.
Later,
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Wow.. ok einstein, just grab a chip like someone above said it is pointless to drop money into an eta.. I think a chip makes a very noticeable difference you'll enjoy a cheap mod like that, i know i did. Some advice the best chip you can get is from MarkD and im not just saying this because he is based out of Toronto (where i am) there have been tests, many reviews, and group buys from more than one e30 forum (i.e r3v) his software is also cheaper.. if you want more info come onto http://www.maxbimmer.com and ask around. Hope that helps
Good luck
just take a driving class so you get better at driving, then power wont make a difference. you learn how to drive better with a more underpowered car.
__________________ I hate: people who haven't died yet that I hate. L337 Co-Founding Assistant Executive Director Product Maker of Sunset Sig's Inc. 2000 BMW M Coupe - Dakar-II - S52 "You gotta fix the nut behind the wheel before you fix the bolts on the car"
spiff and I can keep up with much higher powered bimmers with our cars in relatively stock form since we can carry our speed through the turns and brake much later
Let's start with the road test. In acceleration, the 325is is only SLIGHTLY slower than the M3. (Zero to 60 in 7.5 seconds compared to 7.1 for the M3. Quarter mile in 15.7 seconds at 88.5 MPH compared to 15.4 seconds at 91 MPH for the M3). AND THIS IS WITH A GEARING DISADVANTAGE !!! Yes, the 325is has a 3.73:1 ring-and-pinion ratio whereas the M3 has a 4.10:1.
Doing nothing other than putting a 4.10:1 differential in a 325is will instantly make it faster than a stock M3 except for top speed.
How is this possible, you may think, because the M3 has 192 horsepower compared to 168 for the 325is?
This is where people's thinking goes wrong about what makes a car fast:
It's not how much horsepower the engine makes; It's better explained by the power-to-weight ratio (the car's weight divided by the engine's horsepower). But since the M3 and the 325is weight about the same, that STILL doesn't explain how the 325is with 24 less horsepower can outrun the M3.
The answer is in the area under the power curve of the engines. You can't accelerate all the way from zero to whatever with the engine always at the peak power RPM... so the shape of that Horsepower vs. RPM graph determines how much power goes to the wheels in real-world acceleration runs. The six-banger power curve is fat while the M3 is more like a spike, typical of a peaky twin-cam four. The area under the power curve of the six-cylinder is greater than the area under the power curve of the four cylinder, for the total RPM range used in accelerating. That's why the 325is is faster when you give it the same gearing.
Originally posted by catalyst.@Jan 1 2005, 08:36 PM I suggest just adding a chip. Pouring money into a eta motor is pointless, save for that s50 swap
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not really that pointless there are things that work better on e then a i for instance turbo if you put turbo on e it will smoke a i cause of torque.
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