Turbo on standard Motronic

[BONNARSKI]

As money is none existant as i'm sure you'r all aware i am wanting to know what the maxiun boost a standard Motronic on my 89' 325i Sport would be abole to cope with. I'm thinking that with a suitable chip, M30 AFM, M30 19lb injectors and M30 throttle body a boost pressure of about 1 bar would be exceptable.
I plan on having the CR lowered and can sort all the various hardware and plumbing its just the engine management is the hold back. If funds would allow a full standalone would be ideal but not at the moment.

Any help appreciated, thanks

[Syncro325is]

Search turbo chip if you want to be cheap at first. Its going to cost when you want to up the boost so you may as well wait and do it right the first time. Use the search bar.

[nando]

... is a bad idea. :p

no way you could run 1 bar on stock management with 19# injectors. Generally you can do 6-7psi on stock management and keep it somewhat (but not very) reliable. you'll want 24# injectors minimum, I'd think, and a "turbo" chip (which really just retards the timing).

with actual tuning a stock B25 will do 1 bar no problem, but that just isn't safe on the stock computer which has no way of measuring boost pressure.

for really cheap management you could always do MS1, a basic kit is like $300. That's probably along the lines of getting a RRFPR and a turbo chip for motronic. MS1 isn't super advanced but it's mature, inexpensive and well supported. there's a couple guys in the UK with tons of MS experience, specifically www.diyefi.co.uk.

[Lee Harvey]

I bar is doable with a chip and begi fmu, you can't do it with 19lb injectors though, and forget the m30 afm and throttle body they aren't needed and won't aid you any. 19lb injectors are too small, 24lb injectors will start and idle stock, and with the afm and fmu dialed in correctly will support 12psi happily all day long, beyond that you have to up the ante to 30lb injectors, which will not start and idle properly in open loop off cold starts, as the ecu ignores your afm tweaking and runs a generic map... designed for 14.5lb injectors... and dumps ungodly amounts of fuel since you now have 30lb injectors. 30lb injectors are still doable, and 37lb have been done, but 30lb are so excessive to manage on motronic with a piggyback chip, fmu, and afm tweaking, I wouldn't bother.

If you want cheap power and reliability with hassle free setup, there's nothing wrong with a turbo chip and fmu. Dialing it in is the only tricky part, and once you're settings are right you're basically done, just have to find the sweet spot on the afm and on the fmu. All of this is done by watching the wideband gauge you will have installed so you could do this.

As for addressing the reliability, most stock m20's with a chip are happy to hold 7-11psi on the stock headgasket and bolts, beyond that they get finnicky though, so I strongly recommend at minimum getting metric blue's, or preferrably ARP/Raceware head studs, and removing and retorqueing them one by one in specified sequence as per Bentley manual instructions. This saves you the hassle of replacing your headgasket which should hold up fine, and gives you the added protection of badass unstoppable clamping force. And if it does blow, well you'd have been replacing the head gasket anyways, so it's a worthwhile gamble to hope it holds coz it probably will and your not out any extra if you end up doing it in the future.

Let me know if you need more info on any of it, grassroots/cheapmofo ziptie builds are my forte hahaha

[brody]

The stock ecu can handle any amount of boost. It doesn't need to know pressure, ever. Pressure means nothing with a MAF based system, it is all about flow and proper tuning.

Check out the WAR chip, it's 350 and you can tune your turbo setup and retain your stock ecu. It gives you control of your actual ecu, it's not a piggyback.

30 lbs injectors will be what yo want. 19lbs is a waste of install time and effort, 24's are borderline wasting time.

All this info about the stock ecu can't do this and that etc is funny. The motronic ecu old as it is, can do much more than anyone gives credit for. After all, BOSCH a billion dollar company developed it not a private individual or small tuner company.

You can run any size injector with motronic, you just have to have the right tuning for it.

[Lee Harvey]

the war chip = no longer considered a "factory ecu" we're talking untuned motronic with a piggyback chip to modify ignition timing tables. The maximum value I specified is essentially the maximum injector control with the factory ecu and afm tweaking. That and you can only modify the AFM so far.

Obviously getting a war chip or megasquirt offers exemption from these limitations as you can tune for larger injectors and elliminate the AFM, but that isn't what the question was, which is why I gave the answer I gave. A Miller W.A.R. chipped ecu is no longer "standard motronic" it's a hacked ecu you can tune on a laptop lol (not saying it's a bad thing, just not what's being discussed here obviously.)

[lostbeachbum]

Yes you can run a turbo setup off of Motronic. We have run two turbo setups using only a turbo chip to retard timing, M30 Maf and larger injectors. Anyone who says it cant be done I'll prove you wrong.

[RickSloan]

Yes you can run a turbo setup off of Motronic. We have run two turbo setups using only a turbo chip to retard timing, M30 Maf and larger injectors. Anyone who says it cant be done I'll prove you wrong.

just because it can be done doesn't mean its a good idea or reliable.

do it right the first time or it will cost you more over time when you buy things twice

[Lee Harvey]

It doesn't cost extra to do it cheaply the first time... unless perhaps you're billing for your labor. The parts aren't 0 value parts if you remove them and upgrade to a mroe hi-tech solution in the future, you can sell most all of them to recoup the costs of the initial parts.

And a modest turbo build can be plenty reliable. However anythign pushed near its limits regardless of build quality will have a shorter life expectancy than something built to handle double or more than you're throwing at it regularly. I'm pretty sure everyone knows that.

[balooshinakus]

It doesn't cost extra to do it cheaply the first time... unless perhaps you're billing for your labor. The parts aren't 0 value parts if you remove them and upgrade to a mroe hi-tech solution in the future, you can sell most all of them to recoup the costs of the initial parts.

And a modest turbo build can be plenty reliable. However anythign pushed near its limits regardless of build quality will have a shorter life expectancy than something built to handle double or more than you're throwing at it regularly. I'm pretty sure everyone knows that.

If you start breaking your motor because you have a shitty ECU, which happens a lot, then you are spending unnecessary time and money to fix problems which could have been prevented if you had gotten yourself proper engine management from the start.

[Lee Harvey]

only after the first one... If you'd have pulled the head to put in a new gasket and ARP's or have it o-ringed, you'd have thrown the old head gasket away...blowing the stock headgasket once isn't any wasted time or money *shrug* I pushed my stock setup as far as I could go while I had a ready to roll o-ringed 885 head fully loaded just sitting till I found that limit. I don'tt hink it would have every let go under 1 bar honestly... I pushed it to 18psi before it popped with the piggy back chip, then finally installed the o-ringed head.

And if I install megasquirt or whatever else, I'll sell off my begi fmu and chipped ecu to someone else wanting a simple quick setup to handle reasonable amounts of boost and make reasonable power, I'm really out nothing at the end of the day, save ridicule from narrow minded individuals who usually have no experience regarding stock motronic turbo builds. *cough cough* To each their own though, I simply offer first hand experience and advice when applicable. It's all about perspective, you can claim the more expensive way is the right way which makes it cheaper, at the end of the day, dollars to cents, a cheap piggyback setup is more than enough to satisfy most and is any easy way to get the ball rolling if you aren't baller status and can't afford to go all out on management from the start, or the though of standalone management tuning makes you aprehensive.

[nando]

lol. so what if you have an o-ringed block? the next thing to go would be your ring landings. detonation is deadly any way you put it. Something is going to give. the ring landings are common, actually. It's just that the head gasket is usually weaker and acts like a fuse.

I would also consider the W.A.R. chip + MAF to not be a "stock" motronic. Of course a MAF can be tuned to measure the total airmass. An AFM definitely can't. Even N/A it can't really read much above 80kpa, after that point it just opens up all the way and goes into open loop.

as far as being a baller... Look - a basic MS build or a WAR chip is going to be ~$350. what does a quality RRFPR cost? How about a reliable "turbo" chip? What is the difference in cost between those options? I bet it's not much.

[Lee Harvey]

you're assuming the HG let go from deformation by detonation, not that factory head bolts with 100-200k miles and more let go. And a begi fmu and a turbo chip will set you back a whopping $200 or so, vs. a W.A.R. chip+maf/injector combo or MS1 or MS2, etc. An ebay turbo chip on 91+ octane doesn't knock limit for me til over 18psi... that's plenty of power for your average DIY'er who wants a cheap hassle free solution. With a WAR chip or MS you are just able to further optimize fuel/ignition for more power, rather than just raise boost til you hit a limitation.

I'll let you know when I blow off my ring lands though :p Either way, cheaper and simpler is cheaper and simpler, again to each their own, just stating the facts of what can be done as an alternative option. While cheaper, I state it's obviously a less customizable and less efficient setup, but cheaper is cheaper, and if you're wanting the bare minimum ecu wise to handle boost, a chip and fmu get you there just right. Look at GRM challenge turbo e30's and similar budget restricted turbo e30 builds where every penny counts.

[Cyrix2k]

forget boost if you don't have much money to play with.

[BONNARSKI]

Funny how i was always told 19lb injectors would do, thought that was abit low myself but thats how you learn lol. Is there any car in particular that comes with 30lb injectors and i can find over here in the UK?

After reading the posts its about the same as i'm getting all over, to go stand-alone, but i just don't have the funds, $300 is a big amount of money if you don't have it, and the whole if you don't have the money don't go turbo mentality is just no help at all.

I'm not wanting big power or the most reliable car ever, it's a 21 year old BMW after all, just a nice amount for abit of road drifting. For big power i have an Evo 2 sitting in the garage, it can do what the E30 can but it eats 4 tyres instead of just 2 lol.

So basically with 30lb injectors, lower CR, MLS head gasket, ARP head bolts, FMU and a good chip and 1bar of boost can be done?