Motronic 323i

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braincat
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Mon Aug 28, 2006 12:12 pm

Anyone else made themselves a Motronic 323i out of their 320i? Just done mine and was curious to see how many people have done the same.
Hyperion
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Mon Aug 28, 2006 12:18 pm

i havent heard of this mod, have any more details perhaps a right up on how you did it?
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braincat
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Mon Aug 28, 2006 12:22 pm

I can't give too much away as the whole thing was perfected by a friend in the business, so not sure if he'd be too keen if he's the first to do it. Involves a 323i bottom end and some 325i bits. Unbelievable amounts of torque and has halved the petrol consumption I used to do when it was 2ltrs - and thats keeping the standard diff.
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Mon Aug 28, 2006 1:42 pm

I assume he's swopped the EFI over but the ignition is still dizzy based ?

lots of work involved to get full motronic inc 3D ignition
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mikey-t
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Mon Aug 28, 2006 1:43 pm

i hate electronics talk! when the garage told me i needed a closed loop system for more power i simply hear "more power" and nod!
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Mon Aug 28, 2006 2:19 pm

Sounds easy to me, bin the 2.0 bottom end, fit a 2.3 bottom end, or better yet fit a 2.7 bottom end, hardly rocket science :?
ed325i
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Mon Aug 28, 2006 2:32 pm

I would like to know how this was done to.
ed325i
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Mon Aug 28, 2006 2:34 pm

About an afternoons work to convert an old 323i to Motronic - plastic bumper 320i ECU and loom, inlet manifold with inlectors, AFM, rotor arm and adaptor, top belt cover plus cap and leads and front pulley. All bolt on stuff, easy but slightly pointless. I doubt it would give any more power at all as you aren't addressing the restrictions (cam profile and throttle body size.
Doing this would the fueling be right for the 323 if the ecu was ment for a 320 ?
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Mon Aug 28, 2006 2:38 pm

The C101 connector is different on a early 323i's compaired to a late motronic 320i so i would say it would take me more than an 'Afternoon' to upgrade the EMS.

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Mon Aug 28, 2006 2:51 pm

two pins in the C101 need swopping dude, I have the pinouts and details on an Excel file if you need them.
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pacerpete
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Mon Aug 28, 2006 3:02 pm

I assumed this top secret conversion was done on a motronic 320I , or is there some sicko retrofitting motronic to a chrome 320 turd, now that is ill !! :eek:
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k130
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Mon Aug 28, 2006 3:16 pm

Hey Chrome 323i's rule!!!

and I'd be really interested in a motronic conversion as my 1983 323i is a bit on the juicy side. I think I can guess how it was done though...

One thing you will find with the 323 M20 (particularly early ones) is that it really needs 98/99 octane if you want to push it.
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Mon Aug 28, 2006 3:21 pm

Megasquirt ECU and an 02 sensor will cure the thirst and gain power, no AFM , easy retrofit and remap til you blue in the face as you add mods.

not exactly the cheapest option, certainly the most flexable, if a little daunting @ 1st
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Mon Aug 28, 2006 4:00 pm

yes mate, malacite auto on the G reg, stock as a rock

Silver one is going to donate the sport leather and OBC midweek, then either be sold as is ( running sweet) or fragged for spares.
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Mon Aug 28, 2006 4:17 pm

yes, the bottom stayed the night, she's ferrying us up to Ace this evening in said chaviot

agreed on the silver turding, has 11 months T+T though and no real faults, she just dont like the heavy clutch and unwanted pinstriping on the O/side
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braincat
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Mon Aug 28, 2006 4:48 pm

My god, didn't expect so many views! Its no big secret, 323i bottom end (reconditioned in my case), 325i inlet manifold/throttle body/AFM. Tried first with a 325i ecu, ran fine but idled low, so put my 320i stage 1 'racing' chip in it which now makes it run super sweet. Power gains are a lot more than expected but still need to put it on a rolling road to check. Oh and you'll need adjustable fuel pressure to make everything run mint. Check in with Fritz's Bitz down in wellington in Somerset if you need the exact process as I wasn't present for most of it. A six-branch on your exhaust will help a lot too as the engine could do with a leg up removing air.
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braincat
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Mon Aug 28, 2006 4:51 pm

Oh yeah, and keep your 320i injector rail fitted onto the 325i manifold.
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Martin323i
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Mon Aug 28, 2006 5:04 pm

My 323i was a 320i '88 about 27 months ago. So running on motronic. Used everything from the 320i.

Engine has a pistonslap, but it runs :)

I didn't really notice a difference in power, but lots more torque.
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braincat
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Mon Aug 28, 2006 5:55 pm

Piston slap?
pacerpete
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Mon Aug 28, 2006 6:40 pm

Piston slap is inherent with most 20 year old 'boat anchor' 323 lumps , the pistons have a very short skirt and at this stage are very worn hence lots of piston slap. Mind you they used to rattle when only a couple of years old ,not that i remember ..... :eek: .

It all makes sense now, fritz has a skip load of 323 engines and has hatched a plan to unload them , based upon talk of 'seasoned ' blocks and pure E21 genes etc etc . Personally if my 320 ( :eek: ) needed an engine , a £200 325 conversion sounds like a much better idea !. :)
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Martin323i
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Mon Aug 28, 2006 6:48 pm

braincat wrote:Piston slap?
Yup, very nasty knocking sound coming from the engine especially when cold.

It has something to do with the piston not fitting properly in the cylinder causing it to hit the sidewall. As the engine warms up the piston expands and the noise reduces or goes away.

I doubt that the motronic setup is the cause. Just engine wear. I have no idea how many miles the engine has on it and who knows if the previous owner(s) ever worried about servicing it.

She's noisy but runs fairly well.
ed325i
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Mon Aug 28, 2006 8:09 pm

Tng21 wrote:intersting read this. I just have a 2 door 83 323i which is out but have a spare one to go back in. I have a 325i inlet man / Tb / and Afm. IS it just a case of swopping these? Or have they gota be set up properly
It would be best to have a live remap by somone like chipped uk who can get it running spot on.
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