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Discussion Starter #1
I have been doing extensive research using the search fucntion, on which gear ratio I should choose for my 330ci 5sp and it really boils down to a 3.23 ratio and a 3.38 ratio.

Everyone says the 3.46 is way to aggressive for a 5spd but yet some ppl say 3.38 is ideal, but there is not much difference between a 3.46 and 3.38 2.5%

I want good gains on this gear swap, but I don't want a completely unusable first gear and excessively high reving engine on the freeway etc. I have seen the rpm calculator and all, but its a little hard to really guage the overall impact of gearing using objective numbers.

Some People say the 3.23 is ideal for a 5spd, but not a 3.15 again the difference is only 2.5% between the two.

Does 2.5% more of a difference than I realize?

In the end which is best 3.23 or 3.38, which of the two should I get?

Tom
 

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Discussion Starter #3
Top speed isn't a real concern, my concern is an engine that is too revy and gears will blow by a too fast and at the same time I want to have good gains.

Tom
 

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E46-free since 10-13-06
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Do some basic math. Figure out the percent change between your current ratio and the ratio you are considering. Drive your car and see how many rpms you turn at whatever your target speed is. Then add on whatever percent you calculated for the swap. Simple, now you now your rpm at any speed you are interested in.
 

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Problem is that a 3.38 is very hard to come by. They are only found on 330 cars with auto. Thing is, because they come off of that car, they are VERY easy to swap onto a 330.

I'm dying to get this part for me 6speed. It allows me to hit damn close to 60mph without shifted into 3rd! That will save me such a crazy amount of time in the mad dash towards 60mph
 

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Discussion Starter #6
slow323ci said:
Do some basic math. Figure out the percent change between your current ratio and the ratio you are considering. Drive your car and see how many rpms you turn at whatever your target speed is. Then add on whatever percent you calculated for the swap. Simple, now you now your rpm at any speed you are interested in.
Objective numbers and all that just doesn't work for me vs. getting some subjective feedback. I appreciate input and what you are saying, but I have read prev post about this and I can't really get a great sense of what it will be like with doing mathematical formulas.

Tom
 

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A 3.38 is a 15.3% increase over your 2.93. That would be OK for me but not for everyone. I swappped a 3.46 for my 3.07 (12% increase) and it increases the revs about as far as most people would be willing to live with.

For you, maybe a 3.15 might be a good choice? 7.5% change, which would add noticeable punch, but still small enough that the added "reviness" won't be annoying. 3.23 is going to be impossible to find for less than $1000. 3.38 more like $750. 3.15 for a bit less, maybe grab one for $350 from a 325 owner who switched to a 3.38 or 3.46
 
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