V8drummer

iTrader: (5)

Not bad, what had you done to it at that point?

JakeBreyck

iTrader: (1)

I removed my maf, both distributors, and just about all the other electronics and it got a whole ton faster. :-)























Oh wait..... that might be because of the electromotive i added.

Ali SC3

iTrader: (10)

Also you still have no idea what the ecu is doing with the timing, I mean if it doesn't know the load it can't be using the optimal timing, it must have dialed back alot of the timing. So basically you are now running richer across the board with less timing and just a guess but probably not much timing advance when you need it in (cruise), i mean really how would it know you are cruising without a maf.

If you think about it you have just reverted about 10-20 years in technology and made your EFI system dumber than a carburetor (goes off load) and distributor setup without basic vacuum advance. the funny result is those cars felt more powerful than their smarter counterparts, they just wasted fuel and emissions were awful.

BartleDoo

iTrader: (1)

Well we do have some idea of what it is doing with timing with maf connected...screwing it up big time. It may waste fuel during cruise without maf because of the one-size-fits-all fuel map, but it is definitely not running less timing than with maf, at least not in our cases. Like I have implied, timing could be dialed back relative to the state of our factory new cars, but it is certainly not dialed back relative to how they currently run with maf.

It may be dumb and inefficient, but I'd rather have my car run better.

RedPhoenix

iTrader: (10)

Im borrowing a tail pipe sniffing wideband, Ill post my results.

95lexDream

Ran my car with no MAF for two days because my maf was going out. Got my new MAF (thank you Adiga) and put it in. I would have to say overall that WITH the maf its quicker. At low amounts of throttle at various speeds it is a bit torquier with no maf. The upper end died with no maf though. I put it back in and on the freeway alot more power with the MAF.

RedPhoenix

iTrader: (10)

Well for ****s and giggles, I added a SAFC2 and Innovative wideband on and street tuned the car. With the SAFC2 zero'd out, the car will cruise at 14.7ish and at WOT it will get in the 9-10 AFR range... There is the loss of power right there. I dialed the WOT into the 13-13.5 range and what do you know, the car has more power than I have felt before with the MAF plugged in. I wound up doing around -25%-30% of correction on the SAFC2 to get it to obtain those AFR's fyi.

However with its sweet technology, the stock computer wants to auto correct itself under closed loop, so even at an aggressive -30% correction for 0-15% throttle, the AFR will stay at 14.7 no matter what. So highway cruising gas mileage will not change unless you can fool the o2 sensors to reading differently.

But basically, getting the AFR closers to 14.7 wound up making more power than adding more fuel... but I already knew that .

Going to try and hook up the wideband to Bartledoo's car to get some results with no MAF.



Im going to assume you have a 95 then? It seems only the 92-94 have been successful with this.

BartleDoo

iTrader: (1)

Told you these ecu's are stubborn.

Subjug4tor

iTrader: (1)

What we need is a MAF that lets a bit more air in, but still sends the same signals to the ECU, so the computer thinks everything is normal. I know in the MKIII supras, it is a common mod to use a SC400 MAF and bigger injectors to get more air and fuel without modding the ECU. If you only add a SC4 MAF and no injectors, the supra will run leaner (about 25%).

We need to find a similar mod, but leave our injectors alone. Either use a different MAF, (maybe from a bigger lexus v8?), or trick the current MAF to send an altered signal, telling the ECU there is less air than there really is. Hopefully someone with more knowledge of these electronic systems can chime in.

RedPhoenix

iTrader: (10)

Isnt running a piggyback to trick the maf the same concept? see my post above?

Subjug4tor

iTrader: (1)

Honestly, im not sure. It could all be the same. Perhaps we should focus not on the MAF signal, but the o2 sensor signal? Keep the engine from knowing its running leaner than stock? There must be a way to fix the AFR's on these cars without going standalone, or constantly pulling more fuel with a piggyback.

BartleDoo

iTrader: (1)

Yea that would be nice, but it would need a whole dynamic solution as the A/F's cannot be adjusted a fixed percentage for the whole band. Some ranges need more adjustment than others.

Subjug4tor

iTrader: (1)

I don't know if there are any existing piggybacks that serve this function, but it could work in concept. A wideband could be used to monitor and log AFR's, and then it could send a modulated narrowband signal to the ECU to trick it into pulling/adding fuel. I know that the AEM wideband for example can output a narrowband signal to the ECU so that you can use it in place of the stock O2... all that would be needed would be a program that could modulate the narrowband signal to get the wideband results the piggyback wants.

Ali SC3

iTrader: (10)

The aem wideband has a narrowband signal but it will not work in place of the stock O2 or with the stock computer (i tried). it stays constant at the voltage for a given o2 reading, whereas a real o2 sensor switches rapidly back and forth and the ecu counts stuff during this process.
what you are talking about is an o2 simulator and some piggybacks can simulate the signal to fool the ecu into homing in on a different o2 than 14.7. these piggybacks are more expensive than an safc.

using the safc is the same thing to using a bigger maf except with the safc you can choose which ranges you want adjustment, a bigger maf is a change across the board, but the o2 sensor will correct anyways in closed loop.
pulling 30% is craziness, no wonder the sc400 gets such bad gas mileage.
It seems like this should definitely help out alot, keep us posted.
This way you will retain close to the proper timing (probably increase it some due to the ecu reading 30% less load).

BartleDoo

iTrader: (1)

Ah its getting to be too complicated to consider anything but standalone as the solution for me. Matt, do it so I can copy-cat.

Oh and it's funny that my strategy with the two BS answers on the poll worked in weeding out the BS'ers from tampering with my poll results. 4 people reported faster cars without the maf, and the 1 who didn't had a car that just wouldn't run without it. So, out of 4 people who's cars ran with the maf disconnected, all 4 ran better.