325e M20B27 -> M20B25

[Andy348]

Okay, I've searched quite a bit on the subject.

I've gotten some very different answers... can I run an 885 head without altering my pistons/shaving anything? I've heard yes, no, and only if you're going to turbo.

Ideas?

[lateracer]

What kind of pistons?

Regular B27 - yes, 88 super eta - hell yes, b25 - no (modification required).

[Andy348]

What kind of pistons?

Regular B27 - yes, 88 super eta - hell yes, b25 - no (modification required).

I was hoping to keep my stock ones, but I guess not lol. I'm guessing I'll just get b25 pistons.

For a re manufactured 885 head, would I just buy this on eBay? I found one now for $650.

[lateracer]

I don't think I saw what kind of rods/crank you're using. If it's a stock b27 bottom end, you can use b27 pistons. If it's something different, the answer to your question changes again.

As for buying a head, a new one for $650 isn't bad if it comes with new stuff and a good cam ready to go. For just a head, you can score something used but perfectly good for less than $200.

[Andy348]

I don't think I saw what kind of rods/crank you're using. If it's a stock b27 bottom end, you can use b27 pistons. If it's something different, the answer to your question changes again.

As for buying a head, a new one for $650 isn't bad if it comes with new stuff and a good cam ready to go. For just a head, you can score something used but perfectly good for less than $200.

Sorry, I must have misread your reply. The motor is a bone stock B27, so Ill keep the same pistons.

I'm going to write up a list of what I need when I get home from work, I'd really appreciate if someone could check it. Thanks :)

[Andy348]

Okay, so here's a list of what I think I'll need.

Just a question though - if I save up a bit more $$$, what could I change on this list to give me a bit more HP (if anything)? I was thinking maybe SuperETA pistons or something.

List:

1989 325i Engine Harness -> will anything else work?
"i" AFM, Idle Control Valve, Intake Manifold, Throttle Body, TPS
"i" Injectors - will these work or will I need better than the I ones?
"i" fuel pressure regulator.
"i" speed/crank pully sensor
"i" coolant sensor
"i" o2 sensor
"i" head (885?)
"i" DME 173
"i" engine harness
"i" exhaust
"i" brake booster cables

Anything else?

[lateracer]

Okay, so here's a list of what I think I'll need.

Just a question though - if I save up a bit more $$$, what could I change on this list to give me a bit more HP (if anything)? I was thinking maybe SuperETA pistons or something.

In the cheap, quick and easy department is using M50 injectors and a matching chip for a little extra oomph. Otherwise, you're pretty much there.

Also, keep in mind you've got about $100+ in parts that aren't listed that you have to/should change at this time (timing belt, head gasket, head bolts, water pump, valve cover gasket, rocker plugs, intake manifold gaskets, etc.) Otherwise you may go crazy trying to find new leaks that show up on your new-to-you motor. I had a ridiculously huge leak from my old intake gaskets that resulted from me just being cheap. Nothing like doing a job twice to learn that lesson.

[Andy348]

In the cheap, quick and easy department is using M50 injectors and a matching chip for a little extra oomph. Otherwise, you're pretty much there.

Also, keep in mind you've got about $100+ in parts that aren't listed that you have to/should change at this time (timing belt, head gasket, head bolts, water pump, valve cover gasket, rocker plugs, intake manifold gaskets, etc.) Otherwise you may go crazy trying to find new leaks that show up on your new-to-you motor. I had a ridiculously huge leak from my old intake gaskets that resulted from me just being cheap. Nothing like doing a job twice to learn that lesson.

Can I get a chip for a "normal" 327i stroker?

I'll be sure to add some misc expenses into my budget. Do you mind giving me a rough estimate on what you/anyone else has spent? I'm just looking for ballpark.

Thanks.

[Andy348]

I was just wondering how reliable strokers are. My e30 will be DD'd in the winter also, and I would like it to start! :p

[ForcedFirebird]

Not quite. A b27 bottom with a b25 head makes more power than a b27, but not a b25. Seems to be a common rumor here, but it's incorrect. Every time someone actually posts a dyno chart of a 2.7i, it's not as strong as a b25.

In the end, long term planning and some honest answers should be your guide. What are your plans for the car and how long do you plan to keep it?

A 2.7i is a good street motor for the price and will last quite a while if you take care of it. You get the low end torque that's actually useful on the street and pick up some top end as well. It's also manageable in your driveway without any special tools outside of torx sockets. If you're planning on keeping it for a while, the M50 swap is better than the 2.5/2.7/2.7i but is a little more costly and labor intense.

My 2.5 build is for my track car (spends most of its time at 3K+ RPM) and I don't expect it to live for more than 2 years. If I was streeting it, I would have probably just done the 2.7i build. Metal chunks on my magnetic drain plug sort of pointed me in another direction.

Can't agree more with what rc said about a remanufactured head. I actually have an extra 885 head after coming to my senses about it....lmk if you wanna buy it :)

Since having the emulator hooked up to the e30, I know why they make less power, they need a tune ;) Lean throughout the range, peaking as bad as the 16:1 areas :( Home-brew fix (not the proper way) would be to add the 3.5bar regulator. I used a spare in-line adjustable fuel pressure regulator and turned the pressure up to 65psi and I am finally at 12's WOT and 14's for idle/part throttle. Working on tuning the chip slowly by going back to stock fuel pressure and adjusting fuel. I also feel the timing is way off, just a couple degrees make the off-idle throttle respond well. The e30 will go back on the rollers in good time, shifting the power/torque curve that much requires timing and fueling adjustments from my experience so far with the 2.7i.

Also side note, don't use the 4.10, my car is actually slower with it vs the 2.93 with the exception of initial launch, but the time it takes to shift at ]~25-30mph, then again at 50, vs shifting out of first at 40 might have something to do with it. I would love to trade my perfect 4.10lsd with a low mile for a 3.23 or 3.42lsd, that way you get a little more launch, but aren't shifting 2x as much. IMO the 3.73 is a bit much looking at my last dyno graph.

[lateracer]

^ hadn't really considered the tuning and/or lean running, but it makes sense. Tuning with a wideband and adjustable fpr is a pretty good idea that I might have to steal from you. I don't have the $$ or the sack to leave the motronic system behind just yet.

My track car is running a 4.10 LSD at the moment, and it's just too short. Aside from the fact that 1st gear would only be useful if you were trying to make the car climb a wall, it puts me in a lot of situations on the track where I run out of gear in 3rd and have to shift to 4th, which is too far of a gear difference and puts the motor out of its power zone. Luckily(?), the diff in my vert needs replacing, so I'm swapping in the track car's diff. I got a good deal on a 3.73 LSD at a yard. There was an open 3.46, but I'd rather have the LSD and I only needed a little bit more gearing. If I was streeting this car on the regular, I would definitely go with the 3.25.

[ForcedFirebird]

Well if you don't have a lot of $$ and you have time and/or patience, you can tune the Motronic. I have only started tapping into the code and want to ditch the AFPR in favor of adjusting the timing/fueling in the chip itself. Moates.net has the Ostrich 2.0 emulator for $175 right now and the TunerPro RT v5 software is free.

[lateracer]

Yeah, I've seen the ostrich and think it's what I'm going to use for my first jump into tuning. I've read up on it, and I can't seem to find a definite answer as to what is required/available for data logging with that system. Are you running any kind of data logging with ostrich and tunerpro?

I know people with actual tuning skills look down at those who do stuff like having a friend read a wideband and laptop in the passenger seat while the car is being put through its paces...but it's probably how I'll be doing my first few tunes.

Sorry for the threadjacking Andy.

[cobraken]

Actually, I used the later i harness since it has the easy-release injector plug. I only had to jump 2 wires in the glovebox to the harness coming off the ECU to make the tach and econoguage work, everything else was under the hood. Either way, you will have to open the hole in the firewall a bit to get the ECU plug through it.

Also I just remembered the oil pressure sending unit will work with the new ECU/harness, just clip the plug off the end and put a female spade connector on it, but the dynamic oil level sensor was swapped out. Also the starter wires were clipped and added 2 female spade connectors instead of the eyelets for the small starter bolt connectors.

Try to get the 173 ECU if you can, I have both and use the 153 as my test bed for the emulator tuning now.

I did the 2.7 to 2.5 swap and cant seem to get the tach and econogauge to work. Which wires where those in the glovebox that makes them work? Thanks for all your help.

[ForcedFirebird]

http://strictlyeta.net/technical/328i_8.html

Click on "tach wiring"