Do You Think This Turbo Conversion Is Real

[crazymonk]

Hi, I came across this link,
http://www.m42club.com/forums/showthread.php?t=11880
It shows a really cheap turbo conversion on a 318, but he says he ran a stock ecu with an FMU, would this actually be possible? I'd love a really cheap turbo conversion, as I already have the M30 AFM conversion on my car, so I have the 30lb injectors and bigger throttle body etc with a chipped ecu, so could I fit an FMU and a turbo with low boost? I don't want anything great or reliable as my engine is high mileage and I want to do either a v8 or v12 conversion in the near future so I dont want to get a new ecu right now, just have a bit of fun.

[Gunni]

simple answer is yes.

even the 30lbs injectors @ 3bar will do close or around 300hp.

[crazymonk]

yeah but with a standard ecu?

[Gunni]

if it´s been modified then yea, not 100% stock.

[GeoffBob]

Gunni, I think crazymonk may be referring to using a rising rate FPR. I have noticed that on US forums they tend to call FPR's FMU's (fuel metering units) regardless of whether they are rising rate or not.

Crazymonk, A rising rate FPR with the stock ECU (not reprogrammed) is not a good idea, even at low boost (IMO). Such a system can be made to work, but seldom works well. And you ideally need someone with a dyno to set up your rising rate FPR for you anyway. Call me old fashioned, but I prefer the idea of tuning discrete points on a fuel map to fiddling with rising rate FPR's. But this is just my opinion.

[blue30]

Its true a proper remappable ECU would have been better, but I think the main point about what he did was the low cost. Of course he could have spent more, but I see it as just pushing the boundries of what you can do with very little stuff.

[GeoffBob]

Its true a proper remappable ECU would have been better, but I think the main point about what he did was the low cost. Of course he could have spent more, but I see it as just pushing the boundries of what you can do with very little stuff.

Fair enough, but may I point out that the thread ends with his engine busted.

Incidentally, I can heat my sitting room faster/better by throwing a few litres of petrol over my electric heater. I'd be astounded, however, if anyone came back after I'd burned up my settee and said that my actions were a tribute to what can be done with a few litres of cheap petrol and that I was an inspiration to those amongst us who want to heat our homes on a budget .

[staley_turbo]

Incidentally, I can heat my sitting room faster/better by throwing a few litres of petrol over my electric heater. I'd be astounded, however, if anyone came back after I'd burned up my settee and said that my actions were a tribute to what can be done with a few litres of cheap petrol and that I was an inspiration to those amongst us who want to heat our homes on a budget .

Ive told you a million times, don't exaggerate!

[blue30]

Its true a proper remappable ECU would have been better, but I think the main point about what he did was the low cost. Of course he could have spent more, but I see it as just pushing the boundries of what you can do with very little stuff.

Fair enough, but may I point out that the thread ends with his engine busted.

True that! He was running standard CR, with no way to tweak the timing, on a 170K engine... perhaps a touch less boost would have been advisable, still I guess it was a fun experiment!!

[GeoffBob]

True that! He was running standard CR, with no way to tweak the timing, on a 170K engine... perhaps a touch less boost would have been advisable, still I guess it was a fun experiment!!

It's not just the inability to adjust timing that bothers me, it's also that a rising rate FPR adds extra fuel as a function of manifold pressure only. This would be fine if the manifold pressure were an indication of the mass flow rate of air into the engine, but unfortunately it isn't. The fact is, to measure the mass flow rate of air into an engine requires the use of either a dedicated MAF/AFM type meter, or that both the temperature and pressure of the air entering the inlet manifold be measured (as in the case of a speed-density ECU). This is down to the fact that the density of air is a function of its temperature. Pressure alone (such as the manifold pressure pushing on the rising rate FPR) will only work (marginally) to provide the extra fuel required by the engine under boost at one unique value of temperature. At all other intake temperatures the engine will run either lean or rich. You can only begin to imagine just how badly such a system will perform in the absence of an intercooler after the turbo. And even with an intercooler the air temp will still span too wide a band to make the rising rate FPR of any use.

Agreed though, not a bad experiment if you can laugh it off when the engine pops and can call a friend for a tow home. Aside from that, the best place for a rising rate FPR is in the dustbin (well, that's my opinion anyway )

[Gunni]

Your comments are 100% valid Geoff.

I have tuned such a system though and it worked flawless. Did it make ideal power at all times? I can´t imagine so. Did it have problems? , no not ever.

The only way this works is if the amount of airflow at a X psi boost is equal to X psi more fuel pressure giving out the required pulsewidth at higher flow rate and the air temp consistency is good.

I do not recommend this way. For a budget setup I´d connect a MAP sensor to the stock ecu and tune that with bigger injectors or the very least higher overall fuel pressure.

[GeoffBob]

The only way this works is if the amount of airflow at a X psi boost is equal to X psi more fuel pressure giving out the required pulsewidth at higher flow rate and the air temp consistency is good.

It's the air temp part that bugs me Gunni. Down here where I am (at 5500 ft altitude) our winter mornings start out in the lower 10's and can easily rise to late 20's by the afternoon. I personally wouldn't want to run more than a few psi boost on such a system. I accept the fact that you have tuned such a system as this and that it worked, but I think we are both in agreement that it is not ideal. I was thinking that to take care of the timing issues (with the stock ECU, not reprogrammed) it would be possible to use one of the MSD CD ignitions with built in MAP sensor. On these devices you can set the degrees of retard you want per psi of boost. But with such a device from MSD this setup is not so much a "budget" setup anymore.

I do not recommend this way. For a budget setup I´d connect a MAP sensor to the stock ecu and tune that with bigger injectors or the very least higher overall fuel pressure.

Sounds good to me Gunni . Would that include temperature compensation as well?

[Gunni]

Yes of course. The AFM has a standard Bosch air temp sensor, so a open air one rewired into the AFM connected will tell the ecu the right air temp.

AFM is essentially MAP system in a sense since its volume based or depression across the afm based. Then air temp is used to find the density. so converting to MAP on it is very easy.

[GeoffBob]

AFM is essentially MAP system in a sense since its volume based or depression across the afm based. Then air temp is used to find the density. so converting to MAP on it is very easy.

Ah, I see. I never really thought of an AFM that way. But of course you are right, sort of a mechanical pressure sensor. Except that it is gauge presure, not absolute, but still a similar principle to the MAP sensor.

[DmcL]

not meaning to hijack but..

gunni, have u converted an M20 to run a MAP sensor? i keep threatening to do it to see if its easier to work with or give any benefits over my MAF conversion but i havent a clue what MAP sensor would be a good starting point and have a similar voltage output as the M20's AFM. any specific brands or part numbers to look out for when i look for a suitable MAP sensor? also im guessing the only adjustment needed worth mentioning was to the 1x8 AFM map like i had to do with my MAF setup?

short of finding any such info to help me get a head start on it i was thinking of trying to use one of the GM map sensors commonly found in alot of vauxhall, renault and probably loads of other cars. seems to be no shortage of those MAP sensors in the local scrappers.

also curious if i did do that and then added a turbo later would i then be able to fit a 3 bar-ish GM MAP sensor and re-tune for it? thinking that could give motronic the ability to read boost to an extent. maybe not properly but if it was only pegging a certain area of the ignition/fuel maps off boost and another area on boost i could tune the maps specifically to work with the 3 bar-ish sensor?

[Gunni]

You need to alot more adjusting then just the 1x8 map.

As soon as I find time, after the S50 turbo (which is almost done), I have a car coming in for a map sensor conversion. I´ve already written the .bin file for the most part.

You can run any size map sensor.

[DmcL]

what maps did you have to adjust?

for my MAF setup i had to adjust the AFM 1x8 as well as some minor tweaking to some other maps. just trying to get a feel for if a MAP conversion would be along the same lines or not.

[Gunni]

You have to re-adjust all the ignition and fuel maps and the scales.

Lambda 1.0 = 128 no longer applies in a map conversion.