Scott, I definitely agree.
Back to the original post, what we are looking for here are the Dyno results and what a given mod may provide (or what a stock truck is producing). Once my exhaust system is in, I will be posting an additional set of curves to see how much is gained (or lost) under similar conditions on the same dyno.
As a motor-head, I will be looking at further modifications down the line to help get more power, and perhaps more mileage if I am lucky. Up for consideration include the LandTank MAF, and tuning should that be necessary to sort out the fuel dumping at high RPM and load...since the 80 ECU is so far proving not an easy nut to crack, I may need to go the piggyback fuel management-route (modify the MAF signal to fool the ECU maps via a Splitsecond
PSC1-001 Data Sheet).
Plenty of tweaks out there to help gain more power, I just want to always back things up with real data. I am lucky that there is a great dyno facility near me, and I only am charged $75 per session, as it is worth it to me to know what is really going on with the truck, not just via the butt-dyno.
BTW my Audi is actually a S/C 2.8 with the MAF sensor-type system (factory NA also)...ECM has been reprogrammed to accomodate, and I can do minor tweaks to the system via the OBDII, a dongle and my Laptop...just wish that flexibility existed for my Toy!
Steve
Steve
A couple more comments here... You are doing the right thing regarding documenting exhaust gains/losses, my more general comments directed at the stock vs SC/turbo side in the thread. You could always do the 034EFI IIc system, seems like you are really close to them, and that setup works on 6cylinder engines too. BTDT.
WRT the Split Second - not sure that's going to help you much without program ability of the chip itself. If you really are going that route, remember it just replaces the MAF signal all-together. But, if you look at the MAF signal voltages that the ecu programming accepts as valid, I'm not sure it matters if you are using MAP voltage vs MAF voltage. Specifically, if 5v input is WOT@4500rpm gives x fueling and x timing, that voltage coming from the MAF or the MAP isn't going to matter? That input voltage has to be rescaled in the tabling.
BTW, WRT the Audi S/C on a N/A engine, I have one of those in my possession for failing emissions right now, a PES kit on a 30v 2.8liter v6 motor. AFAIK, you can 'monitor' values via OBDII port just like an 80, but there's no tuning anything with that port. What minor 'tweeking' are you inferring you can do? Normally Aspirated motronic is MAF input only, but IMO/E, that system suffers the same problem that the F10 would, it's a N/A ecu trying to handle boost, and it's tabling does not do it well. IME to date, with PES marginal programming changes, and overly-optimistic fuel injector sizing (>output claims), the PES system has the same fuel dump problem we see in the 80. I've spent a lot of time working on this PES system to get it to pass emissions, and found that LTFT DTC is not only common, it's the norm. IL EPA doesn't like to see CEL at the test station....
With that experience in hand, I see no great advantage to spending a lot of time 'fooling' the antique N/A F10 ecu in the 80 to be 'boost friendly', by definition it's not. And see no value in 'cracking' the tabling... Why bother when there are a plethora of new modern standalone systems that can do the job, and you can build the individual tabling on the dyno. And pass emissions just fine.
Landtank said:
There was a site out there where a guy documented the early Toyota ECUs. He was mostly working with the early Supras that used Carmen Vortex meters and OBD I.
His approach was to broaden the range of the AFM to encompass the boost areas and then tune by injector sizing and fuel pressure.
Clumsy by today's standards but it got the job done reasonably well.
That seems like it could almost work in early OBDI, the problem I see is the LTFT in OBDII. As WOT is a function of STFT (closed loop 02), you might be able to get WOT Open Loop fueling 'better', but far from optimal. The biggest problem is WOT tables in RPM vs MAF. The tabling can't differentiate between boost at 4500rpm and partial/no-boost at 4500rpm. In this approach, the hardware is accommodating given software, that's expensive and frustrating, btdt. Even with the ability to tune the turbo motronic chips, I chose VEMS standalone for my turbo audi project. VEMS, 034, Megasquirt and others make some pretty cool toys to address the problems of programming. The only issue I see with standalone vs the F10 series will be the ECU>Trans ECU interface of data. But the FZJ80 trans functions to the ECU seem limited, read it appears mostly mechanical interface other than the overdrive conditions.
More .02 arbitraged thru the peso
Scott J
94 FZJ80 Supercharged
Steve
