Cosmoblau basic stroker build

[bradnic]

yeah it comes down to goals I suppose. I do already have a full m20 IX motor with a redone 885 head and new stock camshaft.

I can't see a 2.7i with a 6500 rpm deadline not improving things over a vanilla ETA. So is it worth the extra expense for a 2.8 or 2.9 configuration, especially when I will likely keep a stock I exhaust and ECU on this car? What's that going to buy me - 10-20hp maybe over an un-bored 2.7i? I'll upsize injectors and probably move my M30 AFM from Callie over, but that's about it.

So why risk annoying the spouse by spending an unplanned $2k? lol

[AWDBOB]

Yep, M52b28 crank/135mm rods (i, M52, S52, M54b30, etc). I totally understand that- the stuff adds up so quick, too.

Have you purchased your 885 yet? You should have ForcedFirebird do a 731 head for you and slap it on your low mile bottom end and be done with it.

There are so many stroker configurations. You could do what Betz did and run an M52b28 (84mm) crank, 130mm rods and late “i” pistons to get a 2.8L (shaving deck height of block to get compression where it needs to be). You could do the IE pistons above which use M52b28 crank/rods, bore for 85mm and get a 2.9L.

The reason why I’m questioning your original game plan:

If you just shave your “i” pistons (keeping it 84mm bore) and put them on your 81mm crank/130mm rods you’re not really gaining much at all and putting yourself through a ton of work.

[bradnic]

Why not these?

http://www.iemotorsport.com/bmw/item...iepistons.html

A damn good question. Reusing the original pistons from my donor car was just a way to keep costs reasonable - I’d still have to pay for the 2-3mm skim and buy a ring set - so maybe $60-70 a piston. $200 a piston including rings is pretty reasonable and they’re new from Mahle. Guess I need to call IE and think things through.

Digging into this further, the IE 2.9 ultimate stroker pistons require an 84mm stroke crankshaft, such as an M52.

-85mm Bore (+1mm bore over stock)
-Piston-to-bore Clearance: .002 inches over the coating, measured at 7mm from bottom of skirts
-84mm Crankshaft Stroke (M52 crank for example)
-135mm Connecting Rods (M20, M52, S52, or length-specified H-beams)
-10:1 Compression (This is 91octane friendly with proper tuning).

The ETA crank has an 81mm stoke.. I can try to source an M52 crank I suppose, or move up to the IE 2.9 ultimate 325i stroker kit with the Mahle pistons described above for $2k. I can also look into different pistons like these Carillo M20 2.7 pistons from VAC, or stick to the original plan to reuse the I pistons. No need to bore the block, but for both the VAC or stock pistons I do need to match piston and block height, which depends on whether I keep the e rods or use the I rods. I believe I rods and pistons with the eta crank will lead to the unmodified pistons sitting above the block deck by 2-3mm, or sit 2mm low using ETA rods instead.

good 2.7 stoker info on e30zone

[bradnic]

Why not these?

http://www.iemotorsport.com/bmw/item...iepistons.html

A damn good question. Reusing the original pistons from my donor car was just a way to keep costs reasonable - I’d still have to pay for the 2-3mm skim and buy a ring set - so maybe $60-70 a piston. $200 a piston including rings is pretty reasonable and they’re new from Mahle. Guess I need to call IE and think things through.

People don't believe me when I say read up on M1.0, M1.1 and M1.3!!! You should consider grabbing a M20b25 because parts are cheaper and for some reason everyone loves 24V swaps. Or maybe consider a 24V swap, cheaper parts and more people are experienced with them than M1.0 b27s and M1.1 b25s.

I hear you. For me it was really about getting an M1.3 M20B25 stroker done on this car. I won’t rule out an S54 swap down the road, but I always saw than on a late model E30 with an Mtech2 kit - not this car. As to M50/M52 etc it’s more modification than I’m really after. Since I’ve got multiple cars I want each of them to have their own unique flavor. I do want 24V but it will probably be on a newer car

[paynemw]

People don't believe me when I say read up on M1.0, M1.1 and M1.3!!! You should consider grabbing a M20b25 because parts are cheaper and for some reason everyone loves 24V swaps. Or maybe consider a 24V swap, cheaper parts and more people are experienced with them than M1.0 b27s and M1.1 b25s.

[AWDBOB]

Why not these?

http://www.iemotorsport.com/bmw/item/M20B29mmiepistons.html

[bradnic]

So I gave up on getting the E+motronic 1.0 bits working properly. The last straw was a small fire caused by a bad fuel hose I should have replaced... fortunately no real damage occurred except for some top end sensors and harness.

The good news is I was planning to do an E to I swap anyway. With Callie the convertible back in town awaiting engine and tranny removal for it's MM3.2 swap, I might as well get my parts car's I pistons ready to do a 2.8 swap on this car. That way I can pick the modded pistons up from Metric Mechanic at the same time.

Gonna follow the strictlyeta.net 2.8 swap post and keep things simple by using all OEM bits for the top end and ECU. I have a 3.73 LSD lying around so I'll swap that in as well.

Stay tuned.

[bradnic]

Still not running properly - at least I'm keeping the miles off.
Couldn't help but learn about ETAs and 1st gen Motronic, cold start valves, themotime switches, reference sensors.. Also learned how outrageously expensive they are - $300+ for a cold start valve, $200+ for a Thermo-time switch. insane.

The thermotime switch turns on for eight seconds when the engine is cold, enabling the cold start valve to spray fuel into the intake. it's basically a 7th fuel injector in an M20. If either of those components are defective your car is unlikely to start.


There are other components that could be a problem too.


So with help from @jeffnhiscars, I've determined that both the cold start valve and the thermotime switch are working fine. I also had a spare ECU I swapped in - no effect at all.

I also connected with the PO and verified he was having similar issues a while back that he was unable to resolve. So at this point I'm suspecting the high pressure fuel pump, but it could also be the position sensor. I'll be checking fuel pressure this weekend.

Many thanks to Jeff for shipping me spare parts for testing.

[bradnic]

OMG that's awesome. lolol

[audiquattrot]

I have also been upgrading the audio to a refurbished 5908 and a retrofitted BMW Sound System setup. A trunk amp and subwoofer are in the works as well

here's a link to the ports I got, since I know you were asking about them.

https://www.amazon.com/Precision-Port-Flared-Speaker-Cabinet/dp/B0002ZPR6A/ref=sr_1_22?keywords=speaker+port&qid=1558714477&s=gateway&sr=8-22

[mike.bmw]

Very nice! Those ACTs look great on the car.

[bradnic]

Well cosmo has been sidelined for the last 2-3 weeks due to what is probably an ETA cold start valve issue - super rough idle, running very rich, no power. plug wires are brand new Bremi, spark seems ok on all cylinders. I will hopefully have her fixed Memorial Day weekend. We will see.

I have also been upgrading the audio to a refurbished 5908 and a retrofitted BMW Sound System setup. A trunk amp and subwoofer are in the works as well

[bradnic]

Have you broken the news to your wife yet? haha

Lol I did yesterday - had to explain why I loaded my floor jack in the allroad yesterday :D Showed her the pics afterwards and let her know the rust was under control.. Appreciative facial expression ensued lol.

I've got this.

[2mAn]

Have you broken the news to your wife yet? haha

[agent]

Looks like a nice pick up!