MAF vs MAP sensor?

That sounds good!! Can Jim recommend someone of his talents here in SoCal?? Or can he do this from utah? I think plugzits issue was if the stock ECU would work with a MAP conversion from MAF though.

 

What you are saying is exactly right IMO. The “ultimate” for most people is to leave it the heck alone. The next step is to put on a few tweak, I think tuning the stock ECU falls in this heading. You have it, it’s reliable, it works good. The problem is that tuning it is beyond the ability of 99.99% of the automotive enthusiast world, you need to have a clear understanding of programming or find someone who does to even attempt it. I’ve done some programming in my youth and I think that with 2 or 3 years or trying I could probably learn to make basic adjustments to a stock ECU....but that is a long way from comfortable and exact.

I think that when you start talking about reprogram a stock ECU to it to ignore it’s MAF or something like that is when you’ve crossed past the tweaking line. It’s going to mean new code on the chip and months, if not year of de-bugging. At that point I think the best answer is an aftermarket ECU. Most people would be really happy with something simple like a Haltech E6x that would run about $1200, wire it in to the stock harness and lets you tune to yuor hearts content. Aftermarket ECUs are just so easy to tune most anyone can do it, certainly any shop with a dyno can tune the car for you if you don’t feel up to it, no hunting for a specialist on your make and model car.

Some applications are more complicated and mean spending more money on the ECU, I’ve got one of those, I wish I didn’t, but I do. The latest generation of motec lets you extract the last little bit of hp. Say the rear cylinders run a bit hotter, no problem, add a bit of fuel of a little less timing to just those cylinders, no need to punish the front cylinder because the rear cylinder are misbehaving. My problem is the big injectors I need at full power are uneven are low power, no problem with a motec. But most applications don’t have any of these problems and won’t benefit in any way from having the added flexibility in tuning….it’s just a waste of money.

No bashing from me.

 

yup, provided you have a pretty stock-like setup and aren't trying to do anything wierd.

 

Agreed! With the motec will the car run right after install then you tweek from your laptop screen to get better running? Then either a year trial and error seat of the pants or some hours on a dyno? I guess I am asking if there is a base map in there that will always at least get your car started?

 

No, not really. That is part of what you get buying from a dealer with experience...they have maps for similar cars. Now, there are a lot of guys on f-chat running motec and other brand ECUs that would probably be more than happy to share their map with you. Even without that help, writing a base map to start the car is pretty simply really. Figure 4 hours on the dyno to get it perfect working with someone with 1/2 a clue.

Really you can get pretty close without a dyno using the O2 readings...for my 2 haltechs,I did mine the best I could driving it, then an hour on the dyno to tweak the timing a bit and it was done. If you can fing a nice bit long hill, that helps to load the engine a bit and you can use the brakes too, but only very very briefly if you don't want to fry them...the dyno is much faster and easier though.

You might spend a few months playing with little thing like cold start and such, but once it's done, it's done and you drive it.

Again though, if it's basically a stock engine with maybe an exhaust or something, an aftermarket ECU is probably a waste of money. If you want to lose the MAF sensor though or add fuel for nitrous, or add a turbo or blower, an aftermarket ECU is by far the easiest way to get it up and running right. the stock ECU could be made to work, but there would be a lot of re-programming involved to get it right (which for more of us isn't free), vs. pay a couple grand for a new ECU and 12 a day on the dyno.

 

Great post!! Makes tons of sense!!

 

Mark,

You can do anything that an aftermarket ECU can do w/ the OEM ecu.

Please do note that Robert Bosch basically "invented" fuel injection (along
w/ Bendix). They have 125 patents on EFI alone.

Base maps can be worked out for most conversions simply from "math"

(Yes, I know - everyone hates math, and physics, and chemistry )

Example: for a MAP conversion, simply set the new "VE" table to 1.00 and
you will now have an engine that starts.

Alpha-N would be a bit harder, except that the OEM has likely already done
for us a calibration of a decent A-n table for emergency operation.

So, from a MAF system to either a MAP or an A-n system, you can just
start and go. It will need tuning, but it will likely "run" decently.

As far as the difficulty of calibrating OEM (vs Aftermarket) ECUs, that too is
about to experience a quantum leap.

Jim

PS: I've tuned a large number of OEM ECU's to added mods like Superchargers,
Turbochargers, etc. The cost per "kit sold" is an order of magnitude cheaper
than purchasing an aftermarket ECU. Seriously.

 

Man, you just are not listening to what is being said here. If the car runs better with the maf’s unplugged there is some thing wrong with your car to begin with. When unplugged the ecu’s go into default parameters to let the car run aka limp mode. The computers needs the maf input for things like air temp, air density etc. your ls motor is running a map if it is tuned without a maf. If not run from that tuner.

Air temp and density greatly effects the fueling needs of a combustion engine. Efi for the past 30 years or so have ran sensors to compensate for these condition. Then even better are things like 02 sensors that can give feedback to trim fuel needs.

If you can understand what I am saying here you will see that running without your maf’s or some sort of map conversion is bad news and not optimal. Plug them in and find the problem with your car. Then thank all here that have saved your motor lol.

 

Technically he's running Alpha-N. In "backup" mode (with the MAFs) disconnected, the ECU is reading the throttle position sensor (TPS). It is possible to tune the Alpha N maps in the ECU just like it's possible to tune the MAF based maps. What he is probably giving up is driveability, emissions, and fuel economy. I've only ever seen Alpha-N used on track cars as it works great at WOT but doesn't give the best part throttle response, emissions, or fuel economy. Not the way I'd do it for a street car, but it's a valid path none the less.

 

So tell me why I am getting no CELs, my fuel economy seems the same, the temp guages are well within normal and the car is hardly in limp home mode and it is much much faster? The car had no stumbling issues with the stock exhaust sans mufflers. Read the times given for 100-160kph (60-100mph) and comprehend how strangulating that stock exhaust really is.

I do have drive-ability issues only when jumping on the throttle, a slight squeeze initially gets around it otherwise it has sharp throttle response and boy does it go now. I will be trying to tune it in the first instance with the MAFs connected. It is common knowledge among Chev LS motors with mods that MAFless tunes are the way to go. I have one, brilliant, now if I can only get this 575 to beat a lowly Chevrolet.

I don't know about "thanking all here" however, 99% just want the sound improved, they don't care if their stock exhausts have crimped bends and performs no where near what is possible. I have searched and searched and excepting the aftermarket found nobody who has done the whole exhaust system, done a re-tune and posted the final results. The aftermarket are not much help in the tuning dept.

 

Sorry, should read the aftermarket exhaust suppliers are not much help in the tuning dept.

 

Yes of Corse you can map with tps and rpm input only but the ecu will be blind to load. A race car or any other vehicle for that matter is not mapped without a map or maf sensor.

 

WRONG! I know several BMW racers that are doing JUST that, running pure Alpha-N all throttle angle and RPM, no MAF or MAP. They do have temp sensors and barometric pressure sensors to make density corrections, but NO MAF or MAP. Don't forget that you still have the O2 sensors too.

In fact if you do a little Googling you'll find tuners doing Alpha-N conversions on cars by doing just what I suggested in my previous post. They are removing the MAFs, and tuning the "limp home" maps (which are Alpha-N). The only other mod is they are having to install is an air temp sensor for the DME because most DMEs get air temp readings from the MAF.

Trabots, take note you will probably want to install an independent air temp sensor and have the car tuned... Evolve motorsports was doing the BMW E39 M5s this way maybe you should give them a shout. Or you could ask Jim "Landshark" Conforti if he's interested in doing it for you, he's the grand daddy of Motronic reverse engineering and tuning (sorry Jim, not trying to make ya feel old!) I met Jim many years ago in VA at an event with Rob Levinson and his BMW 332ti. I'm an engineer, so I picked Jim's brain a bit, for those of you that don't know him, Jim knows this stuff cold...

 

Yes you are correct it can work just not as well as load based mapping.

A combustion engine that has very little to no intake pressure change can tune well without load input. However in this case do to the intake manifold design and cam overlap with the stock cams it will make for a very poorly tuned car. It can work well with a combustion engine that has very little to no intake pressure change. Not the case with this vehicle.

To the op. By running with the maf unplugged your computer is using a default tune and is blind to load changes and air temp. It will run and can even be tuned without the maf’s but not the best approach. If it is running better with them unplugged they may be damaged and need replacing. It simply should not be faster or run better without them.

 

Wrong again! It IS load based mapping. The load is inferred from the throttle angle and RPMs. The big drawback to Alpha-N is that you have to retune if you make any changes to the engine (cams, etc) and also to account for aging because all of these change the volumetric efficiency (VE).

 

Wow don’t quit your day job.
Load can not be calculated with rpm and tps. It can be estimate and that’s it. I am not sure what your background is with mapping but I can guess its limited to the internet. All modern managements have true ve mapping (Motec,Bosh)or some form of multiplier table such as load comp correction. All this is calculated from load whether it be a maf or map.

All those bmw guys have long quit with the alpha-n stuff. It was a fad for lazy mappers. Some jumped on the band wagon and quickly went back to speed density. Some of the mega squirt quys also play with this alpha-n. Do I need to say more(mega squirt) reminds me of the old radio shack electronics kits I had when I was a kid.

To the OP. Sorry for side tracking your thread. If you would like to discuss this further pm me. I do not wont to clutter this thread anymore.

 

Wow, nice ad hominem attacks... You have no idea who I am or what my knowledge base is. Your guess is wrong (AGAIN!) I have actual experience mapping with widebands and data collection on the road and dyno. There are quite a few very knowledgeable people successfully running Alpha-N (including a bunch of well know E30 M3 guys) and Mega Squirt, not just "lazy tuners".

I don't plan on quitting my day job, it's much tougher (and pays loads better) than tuning or turning wrenches.

Also, it sounds to me like you may have just quit your day job Alex, how many customers did you leave out in the cold when your "speed shop / tuning business" folded this year?

 

Thankyou recent posters, your ideas have helped. I think my occasional stumbling after installing 3inch pipes on my 575 was due to the ASR. I was hitting the throttle at 100kph in 3rd at 4850rpm and sometimes getting a stumble and a flat feeling although still stronger than stock. Surely the ASR would not be activating under these no wheel spin conditions? I made sure and saw the ASR light flash at the same time it stumbled. Could that be why it felt so much better with the MAFs disconnected? Is the ASR only connected to the MAF side and not the limp home map? In any event with ASR switched off it doesn't stumble and goes like it did with the MAFs disconnected. It is truly quick now.

I am toying with sending my ECUs to either DMS or Powerchip with reservations because their tunes while giving almost 40hp on a stock 575 are not a tune for a 575 which already is making at least 50hp more than stock. Do any of you have any thoughts? There is nobody in Perth who can re-map these ECUs. The Ferrari dealer can only look at fault codes but not get inside to re-tune. They actually send customer ECUs to Powerchip for customers.

 

Very interesting things.

I'd like to learn as much as i can about cars in general so if i may a few questions.
Again, i'm curious and interested in the information despite how wierd my questions sound

1. Can any OEM ecu be 'cracked' and then do whatever you want to it ?
Ex: delete the variable valve timing ?

2. Is there a list of the Bosch versions that we're cracked/chip succesfully ?
Ex: under Motronic 5.2 yes, above no?

3. A standalone. Can it use the OEM sensors ? (and just make a new wiring loom)

4. Can a standalone (doesn't matter how expensive or unwise it seams) ecu be a 100% replacement or an OEM one regarding drivability ? (closed loop system, ajusts to every changes of the environment air, temp, engine wear etc)

5. Can a standalone use the stock variable intake manifold system ? (like the F50, BMW E34 M5's - that internal butterfly that opens/closes at various rpm points etc)

6. Can you recommand where i can get more knowledge about engine management, everything about cars (racing engines in particular) or what books to search for.

Basically, i'm trying to ask is how much you can modify a car in a way you want and still run good/reliable (no after more power) ..regardless of how 'digital' /complex they are.


Any imput is of great help.

Thank you.