M20B25 conversion lives!!!!!!!!!! Yaaaaaaaaaaaaaaaaaaaaaaaay

varden · Post by **varden** » Mon Sep 07, 2009 4:43 pm

Retrobeemer wroteHow soon will you be driving it to check out the performance?

Just as soon as i have fixed up the exhaust and added some more zip ties to my oil cooler.

I've got tomorrow off and hopefully being dragged around the shops to look at furniture will only take till lunch time and i can get into the shed for the afternoon.

murran wrote:cool gasket making skills there. the gaskets you get with aftermarket pumps are always shit.

looking forward to hear from you after driving it!

Believe me I'm looking forward to driving it. I will be posting some footage up on youtube of its first test run once i establish a place to wedge the video camera....

Thayat wrote:Great result Varden. I have run into one or two problems myself.

The engine and componentry is missing a few vital bits. The vacuum hoses that connect the brake booster with the inlet manifold and the oxygen sensor (bugger). I have the e30 water pump with only the single outlet and also standard E30 325 fuel pump.

So if I am right, I either need to mount the fuel pump somewhere under the car (any photos of a standard E30 installation as google isn't helping), or get a 318is pump (not an option in NZ), or get an e21 323i pump to mount inside the tank???

With the water pump, I need to get an e21 one and mount it so I can keep the expansion tank. I take it there are no other solutions?

With the oxygen sensor, I have the standard e21 exhaust manifolds. Is it wise to mount to only one of the branches or should I run it along to the point where I will join the two pipes into one?

Its getting to the last bits and pieces. The troublesome ones.

Any guidance from anyone is welcome. I'm getting some pretty ordinary advice from my mechanic unfortunately.

Can you use the one off your e21 manifold and jut add in a joiner and some extra pipe?

Can you steal the water pump off your 320 motor or is it a 4cyl? I thought about making up a T junction out of metal tube and just cutting the hose that goes over the top of the timing cover and adding the junction there connected up to overflow bottle....but I didn't have any of those bit lying around to do it with so i brought a new water pump.

Any m20 up to 1988 should have the same waterpump as yours as it was the facelift model that went with the new arrangement.

As for the fuel pump i would start with the e30 325i in tank pump and go from there, i think the full 323i e21 twin pump set up is over kill as murran is running a modded 325i in tank fuel pump in his 320 hooked up to a 7.5 amp fuse to the motronic plug. If the 325i pump doesn't work out then try the e21 in tank pump and hope it is up to the job.

From what i've read on this forum the 02 sensor needs to be as close to the head as possible as its a narrow band sensor with no heater element (!!??).

I've only got the sensor in one branch mounted in the collector, getting both would mean the 02 would be a metre from the head, not flash.

Ordinary advice from your mechanic....

He probably thinks your bonkers! Unless he's a specialist then he's waiting for you to bring it to him to sort...$$$$$$$$$$$$$$$$

Man i would HATE to think what paying someone to do this conversion would cost. You'd be paying for their expertise afterall or worse yet you'd be paying them $100 an hour to stumble through it like we have!

e21-Mark · Post by **e21-Mark** » Mon Sep 07, 2009 4:47 pm

Mine still runs the regular 323 fuel pump and it's fine although I do plan to replace it with a better one eventually.

varden · Post by **varden** » Mon Sep 07, 2009 4:53 pm

Is that the twin pump set up like mine retro?

Cos i tested for pressure by stuffing the fuel line into an empty kero bottle and it shot the bottle off the hose in the split second i was cranking the car over.

So its prolly well up to the job, I'm just not sure that the single in tank e21 pump is.

e21-Mark · Post by **e21-Mark** » Mon Sep 07, 2009 5:06 pm

Just the single. I've not had any problems - yet.

Duracel79 · Post by **Duracel79** » Mon Sep 07, 2009 6:40 pm

E30 325i runs at ~3bar pressure and E21 323i at ~5-6bar pressure. So no need to worry about pressure capabilities from teh pump.

Flow rate on the other hand, i'm not sure. But my 2.7 engine is being fueled ok on the kjet with standard external pump.

Duracel79

murran · Post by **murran** » Mon Sep 07, 2009 7:30 pm

if going the e30 pump route youll need need a 4 cyl pump as these had feed and return take offs. on 6 pot ones the return take off was on the tank itself.

varden · Post by **varden** » Tue Sep 08, 2009 9:33 am

Progress report!

We brought a lovely swing chair and ottoman combo for bubs room this morning...

But enuff of that. I need to sort this out.

I was in the shed by 2:30pm and had a rummage around for bits of pipe and junctions from my stock of exhaust bits.

I ended up cutting up the 2 into 1 junction from my 325i exhaust and using that as my junction from my headers to the rest of the zorst.

I had to get under the car and lop about 100mm off my header pipes while they were in place so i could fit the junction in.

I used some offcuts to sleeve over the 325i junction so i could slide them neatly over the header down pipes. Butt welding grinder cut pipe ends in place, no thanks.

I still have to sleeve the car end of the junction yet.

Thayat · Post by **Thayat** » Tue Sep 08, 2009 10:22 am

Thanks all. Brilliant to get your input. The mechanic is a specialist. Race prepares a number of cars in our various BMW series down here, did the M5 drivetrain conversion in my brother's e24, and has done all the work on my e21 to date. Has also been very helpful with advice over the years. Just seemingly not now!

If I chuck out the 325 pump assembly and cradle, and get a 318 pump it should fit in the tank in place of the current sender unit yes? (I'm carbed at present).

I can source an oxygen sensor and tap it into just one of the downpipes.

Waterpump I shall either get a replacement waterpump or a tee section (I was wondering about this as a potential solution). The old one is pretty stuffed.

Have I misinterpreted anything?

I'm sure I will have further questions soon.

Thanks again

Daniel

varden · Post by **varden** » Thu Sep 10, 2009 7:25 am

It moves!!

Only a short chug around the suburb incase i suffered some kind of catastrophic failure.

The speedo needs looking at.

The exhaust STILL needs finishing.

I need to fit the viscous fan back in.

I still have to fit the oil cooler properly AND fit my motorsport front bar.

But just from the short bursts in first and second gear its got way more pull than my M20B23.

Wheelspin right thru first gear!

varden · Post by **varden** » Sat Sep 12, 2009 4:41 pm

Progress report!

Attempted to patch up my leaking exhaust, found more holes...

I think I will pay to get it professionally sorted once everything else is done.

I've pulled off my bumper and front valance to test fit the motorsport bar.

I even weighed the out going parts and the bumper, valance and brackets come in at about 10kg.

The motorsport front bar with the rubber bits weighs in at 5kg.

Not a bad saving at the cars extremity.

Now if i get rid of the tow bar, spare wheel well, back seats and belts and swap my 660CCA battery for a 360CCA one it should make even more of a difference.

Where the oil cooler is mounted doesn't get any air flow from the front bar so I'm thinking about putting a line of holes along the bottom of the bar but I am concerned that will ruin the look of the bar.

Or i could get the pipes replaced so i can tuck it up in front of the radiator or something...

But that means spending money and i hate that, i already have a hole saw...

varden · Post by **varden** » Wed Sep 23, 2009 7:00 am

Progress report!

Not much really, i had an hour in the shed while wife and daughter were out this afternoon.

I like the look of this 325i aircon fan in front of the radiator here.

I've lopped off the drivers side towing loop in order to mount up my oil cooler ABOVE the swaybar brackets which tend to get grounded out easily.

The oil cooler will have to be offset to the right of the car to allow me to tuck the oil hoses up out of the way of the wheel and the swaybar.

varden · Post by **varden** » Sat Sep 26, 2009 3:57 pm

More progress!

I've cobbled together all the brackets to mount up the 325i aircon fan and the 325i oil cooler.

I'm pretty pleased with the way the fan mounted up, I've used the OEM rubber mounts to locate the fan, I even got to use my 22mm chassis punch to mount the fan into the rad support panel and do the two upper braces.

I'm not so in love with the way the oil cooler mounted up, for one its offset offending my sense of symmetry and for two I'm not so sure there is enough space for the sway bar to articulate without eventually damaging the hoses.

But its more progress and hopefully tomorrow i can wire up the fan and paint the motorsport bar and give it a test fit.

murran · Post by **murran** » Sun Sep 27, 2009 12:27 am

i looked into fitting the oil cooler on mine, but it looked more of an arse than i could be bothered with. its cold here in blighty anyway.
tho now i have a sump guard restricting airflow around the sump its probably more nessasary now.

sounds well on the test drive! you pleased with the extra grunt??

varden · Post by **varden** » Sun Sep 27, 2009 2:25 am

murran wrote:
sounds well on the test drive! you pleased with the extra grunt??

Oh yes, the cars got that wild push you back in the seat then bounce off the redline quality about it now, its amazing what an extra 200cc's and 7 more years of engine development can do.

It won't be long before i put the stock rims back on it for some more field testing.

varden · Post by **varden** » Thu Oct 01, 2009 5:28 pm

more progress!

Got the motorsport bar on, sorted the speedo, admitted defeat on the zorst, finished off the wiring....then drove the car down to the shops to buy some beer (and some chicken frames for the dogs

).

Flogging the tar out of it at every opportunity and checking for leaks or smoke at every stop.

Took the car for a thrash in the countryside....

Two attempts...

Blew the fuse on the engine fan, will try it on a 20 amp fuse this time.

Also booked in for an exhaust fix for next monday and a pair of new front tyres on wed.

The car was a little rocket in traffic, small car zip with big hairy 6cyl balls!!

it was great, i only did about 30km all up but i was grinning for the rest of the day.

One pic, more to come.