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View Full Version : Lets Get Back To Logical Performance Not Imaginary Swaps!


BoBimmer
12-16-2002, 04:28 AM
OK I understand it is fun to talk about all this stuff but I think most of us are pretty educated and know the logical limits of the real E30 world so lets try and stay within those. But anywaz' enough with my ramblings please dont FLAME me?! But my true question is has anyone done a MAF conversion on an M20 engine that is just lightly modified like intake exhaust and chip? I am seriously considering doing it because I can see some serious possibilities for power there. Any experiences? I also plan on putting one of BMP's multi throttle body euro style intakes on it have head work done and a possible Moesselman turbo kit. Any advice is much appreciated. Since BMP is practically down the street from me!? Does anyone know the best and the cheapest MAF kits to get? also what cam should I get for a 1991 325is auto matic?? Sorry for the long post and thank you guys all in advance for all your continued advice and help on my E30 endeavors! And for putting up with my horribly long ramblings!

Slowered318
12-16-2002, 04:49 AM
Well the first major gain would be a 5 spd manual swap.. Then keep bumping your post.. a few highly modified M20's here but they don't come around too much.

And it that doesn't work find out what this guy did to his engine Race1.mpg (http://w1.226.telia.com/~u22607545/)

BoBimmer
12-16-2002, 05:01 AM
I want to add a five speed but dont know where to start!?? Does it make thast big of a difference?? how much power does the automatic suck down??

SpudBoy
12-16-2002, 12:28 PM
I could be wrong but the torque converter usually saps 10 - 15% of engine power.

Dave 325i
12-16-2002, 12:39 PM
Plus the manual makes your car at least 250 000% more fun to drive.

I've never really heard of anyone -starting out- with the MAF sensor and multi-throttle intake.

Most modded M20s I've encountered on the 'net are usually bored and stroked to 2.7 or 2.8 litres, with a bigger AFM from an M30, bigger injectors, an adjustable FPR among other things.

Cam selection is usually based on what you're doing with the car. To keep it streetable and emissions legal (maybe) you'll have to get a mild cam. If you're planning on racing and lumply idle at 1200 rpm doesn't matter to you, you can get something a bit more extreme.

I hear Schrick cams are generally the best, but that's all I really know.

A turbo will change all of the above, so you should decide if you want that first. Get the manual first though.

Slowered318
12-16-2002, 07:58 PM
The perfect cam for a N/A engine is a lot different then the perfect cam for a Turbo car.. I'm not an expert but for a turbo i think you want short duration, high lift, and not much overlap. this will give you a good amout of low to mid rpm torque while you wait for the turbo to spool up.

E30 Stu
12-17-2002, 10:54 PM
Forget everything that has been posted.

You are going to get NOWHERE with an automatic tranny M20 with boltons, a hot cam, and multi-throttles. Your problem is the BOTTOMEND. If you plan to keep the automatic, putting in a hot cam and multi-throttles will probably slow you down; it will kill your mid range and you'll end up dead in the water.

Here's what you need:
Build a 3.0L Stroker, put in a Schrick dual pattern 284/276 cam, verrrry mild head work, and get a 4.27 or 4.45 rear end. Your car will be a bullet stoplight to stoplight.

The money you will spend on a MAF, multi throttles, a cam, etc, you can have a built, Stroker M20.

bart320i
12-18-2002, 06:31 PM
Save your money and get m3 motor or 328 with m3 cams. Then look into turbo and shit

Jon@Bimmersport
12-18-2002, 08:53 PM
why not M50 motor with M3 cams, bored to 2.9 or 3.0L..then later one get AA turbo

Autotechnica
12-18-2002, 09:11 PM
Originally posted by E46_lover
why not M50 motor with M3 cams, bored to 2.9 or 3.0L..then later one get AA turbo

That's your answer to everything! :madnoel:

I don't think it's possible to bore out the M50 heads to 2.9 or 3.0L, your probably looking at a stroker at best.

Bryan

Jon@Bimmersport
12-18-2002, 09:12 PM
no i meant m50 as in 2.5L..not the M3 motor...if this guy wants to work with the M20 motor im thinking hes on a bit of a budget, so the M50 would be easiest to do...some guy on DTMpower has a "329i" which is his 2.5L bored to 3L

E30 Stu
12-18-2002, 10:52 PM
A 2.9L M50 is not a 2.5 bored out. It's a 2.5L with a 3.0L crankshaft and machined pistons with 325i rods. It's a stroker. You cannot make a 325i motor a 3.0L because you cannot bore the block as far as you can an M3 block. However....there is one exception. But I aint tellin :P

Autotechnica
12-19-2002, 12:57 AM
Originally posted by E46_lover
no i meant m50 as in 2.5L..not the M3 motor...if this guy wants to work with the M20 motor im thinking hes on a bit of a budget, so the M50 would be easiest to do...some guy on DTMpower has a "329i" which is his 2.5L bored to 3L

Yeah what E30 Stu said, you cannot bore out the M50 2.5L motor to 2.9 or 3.0L, you would have to stroke it as well. The M50 cyl head walls are not as thick as the US spec M3's cyl walls so it is not possible to bore it to 2.9 or 3.0L.

BoBimmer
12-19-2002, 02:38 AM
Ok how much would it cost to do a basic motor and tranny swap to a newer more powerful motor and change my auto to a manual? Also how much could I expect performance wise? Is it really worth it!?? THANX FOR ALL YOUR GUYZ HELP SO FAR AND YOUR CONTINUED HELP IN THE FUTURE!

E30 Stu
12-19-2002, 06:15 PM
Originally posted by BoBimmer
Ok how much would it cost to do a basic motor and tranny swap to a newer more powerful motor and change my auto to a manual? Also how much could I expect performance wise? Is it really worth it!?? THANX FOR ALL YOUR GUYZ HELP SO FAR AND YOUR CONTINUED HELP IN THE FUTURE!


You could drop in a 2.5L M50, tranny, and diffferent differential for about $6K total...

This would be about 200hp, 2700pounds....it'll cook.

BMW_M52_M20
12-21-2002, 05:53 AM
Get another bimmer, by the time you have eveything done which will probably take a long time, it will be a very old car (tired engine).
Swapping engines will make you need to do many more mods to your suspnsion to keep the car on the road.
My opinion, not worth it!*no-no*