330itis 15 Report post Posted January 24, 2007 Hi, I am doing a manual conversion in my 318IS which has and m44 motor and Im using the gear box and stuff out of an m43. I have just goten to the stage in the conversion where I need a lower ratio diff. The diff I have in it at the moment is a 4.44 ?? well the tag says 444 so thats my guess. And I drove the car yesterday and the gears are very close together and at 100Kmh the engine revs out to 3600-3700 rpm. so I definetly need a lower ratio diff. What ratio diff do I need for this m44 motor? will a 3.65 do it? what comes standard on a manual m44? looking for quick replys as it is quite urgent. sory Thanks! Quote Share this post Link to post Share on other sites
Carl 3 Report post Posted January 24, 2007 3.91 would be good Quote Share this post Link to post Share on other sites
Gus 5 Report post Posted January 24, 2007 e30 stuff is 4.1, imagine you would be good with that too Quote Share this post Link to post Share on other sites
TronSpec 0 Report post Posted January 24, 2007 yeah 4.1 would be the go with your 1.8 power. If you put too lower diff in then you will have sh*t acceleration Quote Share this post Link to post Share on other sites
drifty325i 0 Report post Posted January 24, 2007 3.91 as well Quote Share this post Link to post Share on other sites
318isCoupe 0 Report post Posted January 24, 2007 3.63 or you'll be revving your nuts off at 100k. Quote Share this post Link to post Share on other sites
Silver Fox 43 Report post Posted January 24, 2007 4.1 gives me 100 k's at 3000 revs, 318i E30, reasonable acceleration as well. Quote Share this post Link to post Share on other sites
drifty325i 0 Report post Posted January 25, 2007 So with Silver foxs car is revving around 3000rpm @100 on 15inch mags, i still think a 3.91 would be the best in your car. Maby a 4.1, depends if you in the city alot or open road driving. If your running oversized mags like 17s or 18s a 4.1 would be worth while imo Quote Share this post Link to post Share on other sites
kerrynzl 3 Report post Posted January 25, 2007 An E30 with a 0.82 fifth and a 4.1 rear has a total of 3.36 overall ratio [2700 RPM @ 60MPH with a 25"diameter tyre][excuse imperial figures] An E36 with a 1:1 fifth and a 3.63 would be revving at 2927RPM @ 60MPH with a 25" tyre It all depends on what gearbox you are using Quote Share this post Link to post Share on other sites
kerrynzl 3 Report post Posted January 25, 2007 the formula is: [RPM x TYRE DIAMETER inches] divided by [OVERALL RATIO x 336] = MPH or [MPH x 336 x OVERALL RATIO] divided by [TYRE DIAMETER inches]= RPM Quote Share this post Link to post Share on other sites
will 169 Report post Posted January 25, 2007 the formula is: [RPM x TYRE DIAMETER inches] divided by [OVERALL RATIO x 336] = MPH or [MPH x 336 x OVERALL RATIO] divided by [TYRE DIAMETER inches]= RPM Hey Kerry, we need to beat that yankee imperial sh*t out of you and bring you into the metric world..!! I would think that I would try a 3.91 first, will give you better cruising but still allow you to get going with your M42 power???.. (bit strange to use M42 and power in the same sentence..!! ) If you want more boy-racer acceleration, use the 4.1. my 2c worth.. Will Quote Share this post Link to post Share on other sites
330itis 15 Report post Posted January 26, 2007 Thanks guys. Well I found out that the M44 manual originaly has a 3.3- 3.4 diff. I just drove down to waitomo with the 4.44 diff and Its like Im missing 5th. Like it revs really high. Im not so sure about the 4.1 diff. I dont think It will be enough. Its a 1.9L motor by the way. but I think the 3.6 sounds good?? Driving down I cained the sh*t out of subaru legacys off the line. quite fun hehe but thanks alot everyone! Quote Share this post Link to post Share on other sites
drifty325i 0 Report post Posted January 26, 2007 3.91 as well Again Quote Share this post Link to post Share on other sites
Carl 3 Report post Posted January 26, 2007 Okay, so I have a good spreadsheet that's tits for calculations. Feed in your specs and slide the slider for a nice little graphical representation. I can't upload it due to restricitions so PM me for it. Quote Share this post Link to post Share on other sites
kerrynzl 3 Report post Posted January 26, 2007 Okay, so I have a good spreadsheet that's tits for calculations. it. Hey Mate, When I use the words "Spread, Sheets, & Tits" in a sentence, It has a totally different meaning.Haha! Quote Share this post Link to post Share on other sites
BM WORLD 1283 Report post Posted January 26, 2007 i have a 3.64 that came from a 318ti ,manual . you would need to swap back cover over , or swap gears over . ti uses e30 type rear end . 021433600 . $250 Quote Share this post Link to post Share on other sites