2.8L M20 9.8:1 stroker build: my 323i reincarnated

[2mAn]

Updates?

[betz]

Swapped with a friend's FPR and it's exactly the same. Either it's the pump or my gauge is off.

[digger]

Could be the tester to

[betz]

I thought so too, so I checked for like the third time lol.



Nope

It appears to hold pressure perfectly though, it's clear the diaphragm isn't ruptured. New fuel filter. Maybe it's the pump, I'm not 100% sure. Cheapest regulator I could find for a Bosch was $100 at NAPA. Its painful to see literally every other fuel pressure regulator is like $80 max. Even the higher pressure 944 one.

[digger]

Looks almost like a 2.5b reg

[betz]

Did the M30 AFM fit mount directly to the OEM airbox?

Yes, but you can only put 2 screws in without modification. I did two screws on bottom and gasket maker up top, worked just fine. I wedged some silicon plugs between the bottom of the AFM amd the airbox to press it into the top of the airbox where the screws are missing. I plan on modifying the airbox later so I can mount all 4 screws and so no plastic is in the way of the AFM.

Other news- looks like my fuel pressure is all f'd up. I'm going to try a new FPR first and if that doesn't do anything, I'll start looking at the fuel pump.

I teed in a gauge to the fuel supply line. Here's what I saw:
Video

Does this look like a bad FPR? Low pressure, not increasing pressure with RPMs. With vacuum line disconnected it reads almost 3 bar. But with revs it doesn't seem to increase that much.

Better vid of revving pressure

[2mAn]

Did the M30 AFM fit mount directly to the OEM airbox?

[Digitalwave]

The dyno wideband will clip into the tip of the exhaust. It's doubtful they would install one in your mid-pipe in place of the stock O2 sensor.

You will benefit a lot from a proper tune, even on Motronic. But you'll really feel a difference switching to Megasquirt, deleting the AFM, and having a fully proper tune done.

[betz]

And man that porsche reliability....kind of amazing.

Right? Subarus had so many issues with their motors, with some of them being absolute dogs. Porsche is just sitting here with higher compression, higher revving, 6 cylinder motors that aren't even meant to be daily driven, but never a head gasket issue.

Anyways. As for my E30, I've decided to try to install a wideband O2. I'm going with an Innovate LC-2. It will let me monitor AFR and simultaneously send corrections to the ECU and I figure I will probably install one eventually so might as well do it now, before the dyno.

[wworm]

Yup that's next to my Boxster. It's been tremendously reliable. Only mod so far is taking out the intake silencer for dat induction noise. Only future mod is a short throw shifter that's waiting to be installed.

I wouldn't hold your breath for the ITBs, but the long tubes will be installed in probably a month or so. In the meantime- I will try and get you a sound clip of it as it sits. I even got an external mic just for the occasion :)

When I worked at Eason Autoworks in Oakland, it was the only porsche I was allowed to drive, haha. Super fun cars for sure. And man that porsche reliability....kind of amazing. Recently tore down an 84 carrera 3.2 block that had nearly 200k on the clock, most of which was hard canyon/track driving (previous two owners raced motorcycles) and the thing was impeccable.

Either way, this will definitely sound damn good. Looking forward to sound.

and a 2.8L M20 is one of the plans.

I'll be pulling out my 2.7 soon :devil: ;D

[2mAn]

I see. Well I hope you're getting the jist from my thread here that it wasn't an entirely straightforward process, for tuning at least. When I'm done I'm planning to compile a list of necessary parts for the build and such, hopefully to make it easier for anyone else attempting the build.

It is very doubtful the first dyno will be anywhere close to 200whp. We're talking a motor with far from the ideal tune, on stock intake manifold, throttle body, exhaust, a pretty mild cam, stock valves, with no porting. But as time goes on and I decide to change some of those things.. who knows :D

Oh yea, I know its not likely to happen without a lot more work... luckily Im well over a year away from any kind of motor swap... you have plenty of time to deal with the headaches ;)

[betz]

It’s got solid compression numbers but there’s a nasty dip in 2 consecutive cylinders, which I suspect to be a head gasket issue. My “stage 2” plan for the stock motor is the head gasket, which I’ll probably add a cam at the same time. If a cammed 2.5 M20 still isn’t enough then I have like 5 different ideas, and a 2.8L M20 is one of the plans.

I really hope this gets close to 200whp though I know the numbers weren’t your goal. I just feel like M20s haven’t gotten a fair chance to showcase their potential

I see. Well I hope you're getting the jist from my thread here that it wasn't an entirely straightforward process, for tuning at least. When I'm done I'm planning to compile a list of necessary parts for the build and such, hopefully to make it easier for anyone else attempting the build.

It is very doubtful the first dyno will be anywhere close to 200whp. We're talking a motor with far from the ideal tune, on stock intake manifold, throttle body, exhaust, a pretty mild cam, stock valves, with no porting. But as time goes on and I decide to change some of those things.. who knows :D

[2mAn]

As for you, if you have a healthy M20B25 I would run that, at least for a while. No need to tear it apart unless you are motivated to build a motor. The 5 speed is a much more important addition to your car than better HP or more torque, IMO. Like I said, this build was never for chasing numbers!

It’s got solid compression numbers but there’s a nasty dip in 2 consecutive cylinders, which I suspect to be a head gasket issue. My “stage 2” plan for the stock motor is the head gasket, which I’ll probably add a cam at the same time. If a cammed 2.5 M20 still isn’t enough then I have like 5 different ideas, and a 2.8L M20 is one of the plans.

I really hope this gets close to 200whp though I know the numbers weren’t your goal. I just feel like M20s haven’t gotten a fair chance to showcase their potential

[betz]

next to your boxter?\

cant WAIT to hear this thing with itbs and long tubes.

Yup that's next to my Boxster. It's been tremendously reliable. Only mod so far is taking out the intake silencer for dat induction noise. Only future mod is a short throw shifter that's waiting to be installed.

I wouldn't hold your breath for the ITBs, but the long tubes will be installed in probably a month or so. In the meantime- I will try and get you a sound clip of it as it sits. I even got an external mic just for the occasion :)

[wworm]

next to your boxter?\

cant WAIT to hear this thing with itbs and long tubes.