Bmw e36 with e46 gearbox!

[Fireball1991]

Hi everyone, would like to ask you, can I put together the m52b20i engine from e36 with the 6 speed gearbox from the e46 320d?

Why?... so... I've a crazy idea. I wanna put an 4.45 dif under my car, ('cause I can't find a b28i engine) so I wanna get more power from it, that's why I would like to get a dif. But if I've a dif, I also need a 6 speed manual gearbox because the rpm change. So how can I get a 200hp from my engine without a new block?

Is the e46 320d gearbox compatible with m52b20i?

[spyderg0d]

gearing doesn't create more power, it changes the relative gearing to the power band the engine produces. Essentially, You want the gearing to match the dimensions of the track. If your doing long extended straight tracks with long curved turns, low gearing for the best top speed is best. if your doing short tracks or quarter miles top speed isnt the goal as much as being at the maximum speed at the line. moreso acceleration rate is more important than the top speed. a higher geared diff will give you a higher top speed, but slow accelleration as the engine wont be in the power band as long. lower geared will increase the ability to stay in the power band and provide maximum acceleration. wtorque vs, whp.

- - - Updated - - -

... yes, as long as its not a 4wd transmission it should bolt up with some combination of factory parts. ..

[Fireball1991]

Thanks for reply. I wanna get a 6speed gearbox cause the rpm. Not for the top speed. For example: with the factory diff I've an rpm about 3000 at 100km/h and with this config I've a 7.5-8l/100km but with the 4.45 diff I'll have around 4000rpm at the 100km/h and the consum data will rise up. So that's why I need to get an 6th speed in gearbox.

Cause with the 4.45 diff I'll get about 40-45 extra hp.

[LSxDreamer]

Cause with the 4.45 diff I'll get about 40-45 extra hp.

False.

[spyderg0d]

Technically you would lose physical horsepower since the maximum amount of work cant be achieved with a shorter gear ratio due to the more limitted amount of top speed over time. at the wheels of coarse. the engines power rating remains unaffected. Like i said. its a trade off of wheel horsepower for wheel torgue.

[E36328Coupe]

False.

While you are right remember that BHP is only RPM*Torque*magic number.

So in a way what the OP is after is to alter the gearing to gain mechanical advantage, more torque at the rear wheels, so the effect would be like having more BHP

[Fireball1991]

Yes of course, I mean it will feels like to be much power 'cause the gear ratio, however it's stay on 150 hp physically. I would like to use the car for a little crazy drifting when I want, but basicly I often use for the long trips, so that's why I need the 6th speed. The whole thing is getting from the "fail engine replace" just because I can't find a bigger engine for her like an b28i.

- - - Updated - - -

- - - Updated - - -

While you are right remember that BHP is only RPM*Torque*magic number.

So in a way what the OP is after is to alter the gearing to gain mechanical advantage, more torque at the rear wheels, so the effect would be like having more BHP

Exactly

[Deus Ex Machina]

The 6 speed will work.

[ed323i]

But, if you don't mind the noise at 4k rpm, then I think you should also calculate how much time it will cost to earn back the 6-speed gearbox (and the time to build it in your car) with the improved economy.. Those 6-speeds are not that cheap I think.. Perhaps best to just change the diff and live with the worsened MPG and enjoy the improved acceleration?

By changing the ECU for a chipped version (like 150 euro on Ebay) you can also gain up to 10 real HP. In my 323i M52B25 the difference is really big. Lots more torque down below and definitely more horses higher up in the rpm range. But then, the M52B25 and B28 were really down-tuned a lot. Not sure about the M52B20..

With the ECU and a bit more moderate diff upgrade, you could also have best of both worlds.. More real HP and torque (great for drifting) from the ECU and a bit more acceleration from the diff, without loosing too much comfort (noise) and economy on higher speeds..

Check out the ECU here: https://www.ebay.nl/itm/BMW-Chip-Tun...S41-1-7100rpm/ . In the past I've chipped a couple of my previous BMW's and some tunes were a bit flakey (sometimes they only tune the highest loads, but deliver a really poor tune for the lower loads for example), but this guys seems to know what he's doing and delivers a proper tune, for all rpm's and loads.. I can truly recommend his tuned ECUs..

[spyderg0d]

I have a 3.91 lsd in my vert with a 5 speed. it isnt that bad if you have a decently quiet exhaust. at 55 its around 3k. 65 is like 3,5k. but, realistically even with the stock 3.15 diff 65 was alittle under 3k revs. so it seems like alot, but its not that bad. unless of coarse your doing an hour of highway driving at a time. I think with my larger wheels i top out at around 120mph. but i can get to 120 ALOT faster than before. every gear shift leaves me in the power band if going for gold.