2.85 (2.9) Stroker with S50 Crank - it lives!

[bimmer_party]

Sorry for thread bump, new here.

This build inspired me to finally set up a r3v account.

I recently picked up an entire ETA motor, i pistons, S50 crank, and some other goodies to go with my rebuilt head and new OE spec camshaft after reading through your build and some of digger's stuff.

So far I am at a total of $200 out of pocket invested, with bottom end hardware and bearings being the bulk of the remaining cost. I am shooting for ultimate budget build here, as it is my first endeavour in building a "custom" motor. I can't thank you enough for posting your info in here.

I am curious how you are enjoying it thus far.

[sert57]

I'm fairly certain the dyno wasn't calibrated properly. I instructed them to take it to 7k and the dyno chart stops around 6. With the rpm adjustment i was in the mid 170s whp. One of these days I want to take it to another dyno shop and get the tune checked out and re-do a pull.

The last few months I was having an issue with my megasquirt where I would get no spark. After replacing the BIP373 and poking around with a multimeter for hours I determined that there was a bad lead on the adapter board between the spot where the spark output was soldered in and the actual output to the wiring harness for pin 1. I soldered in a jumper wire and she worked like a charm.

Also got the bluetooth mod done on the megasquirt in the meantime, so I've enjoyed tuning my 30 year old SOHC car via bluetooth. I mean it IS 2018 haha.

[Kershaw]

I’m blaming the adjustable cam gear. It seems to have shifted so much to the low end and destroyed the top end... this isn’t an eta!

Yeah, 200ft/lbs? Should be 210hp!

[zaq123]

looks like some diesel car dyno

[2mAn]

something is off, a 2.9L with 272 should not peak at 4400rpm.

I’m blaming the adjustable cam gear. It seems to have shifted so much to the low end and destroyed the top end... this isn’t an eta!

[digger]

something is off, a 2.9L with 272 should not peak at 4400rpm.

[AWDBOB]

If you ran it on a Dynojet, I bet you would see +10% in your numbers. Mustang dynos notoriously read low. You're probably closer to your goal than you think, which is why it feels quick on the street!

[ForcedFirebird]

Based on the HP number, it would appear to me that the o2 number is correct, but also a cam tooth off would do similar (your TQ curve looks weird for an m20).

[sert57]

Did the AFM delete and put in a bosch ev1 IAT sensor with a custom made harness to hook into the AFM plug.

Ignore the AFR line - its just wrong



Torque - 205 ft-lbs @ 2500 rpm
Power - 156 hp @ 4400 rpm

Got a dyno tune yesterday at zen motors in Atlanta. Not really sure why my numbers are so low. I haven't double checked cam timing and valve clearance lately. It looks like I could definitely go bigger on the cam, but I don't plan on tearing into it anytime soon.

It sucks as far as impressing people on the internet goes, but it makes a heck of a daily. I'd take a bet its one of the fastest 160 whp E30s out there.

[whitebulat22]

A 3 inch ID AutoZone exhaust pipe will also go in the stock boot with stretching in case a 2.75 inch is hard to find.

[downforce22]

i noticed better throttle response with the afm removed and haven't looked back!

[zaq123]

glad you are working thru all those glitches. This thread could use more pictures or you have a build thread somewhere?

[Kershaw]

Oh you didn't delete that with the original MS install? Yeah, you definitely need to do that. The AFM is a major restriction.

But you don't need to get another AFM. Just use a piece of ~2 7/8" tubing (exhaust, pvc, etc) to connect the elbow to a filter. Drill a hole in the tube and RTV the GM temp sensor in place.

[sert57]

Quick update - ended up buying and assembling a MS2 DIY PNP kit which solved the hesitation issue. She sounds glorious at 7K.

Going to try to get a professional dyno tune done in the next couple of days.

I think I may get a spare AFM and remove the "barn door" so its just a temp sensor. should give OE looks and keep the MS happy, and hopefully get another pony or two.

[ForcedFirebird]

180whp shouldn't be an issue. I just did that with a m52 crank eta rods, "i" pistons, 272 cam, stock valves/ports and a dyno tuned chip.