ArmitageGVR4

iTrader: (13)

Hi PFC gurus. I'm about to replace my M2 ECU with a PFC/Datalogit this weekend and I have a few questions about running the base map with my setup (stock sequential twins, stock fuel system, basic bolts-ons).

1) My motor is street ported. I assume this change in volumetric efficiency will cause it to tend to run leaner under boost because the base maps don't account for the increase in airflow. However, I've always kept the boost down to 10psi on my M2 ECU and had no issues after many years of track days with this setup. Are there any precautions I should take until I get the car tuned? I do not have a WBO2 setup yet but it's on the "real soon" list.

2) The double throttle was eliminated on this motor when I bought it. With the M2 ecu, it seems to exacerbate the 3-4k hesitation/bucking until the car is fully warmed up while at partial throttle and positive boost. Will this continue to be an issue with the PFC until get it tuned or is there any prescription for fixing it with the base map?

3) I presently use a single manual boost controller connected to both the wastegate and precontrol actuators and have had no problems maintaining 10psi boost. I was thinking of ditching it and using the built-in PFC boost control. Would this be more effective? I am worried a bit about boost creep with these new turbos I just installed so I am running on the springs right now at 7psi just to break them in. I didn't port the wastegates D:

Any guidance would be appreciated.

Thanks!

arghx

iTrader: (3)

I'm wary of making predictions, but I'd say you're probably going to be ok in terms of AFR under load if you keep the boost down. That still depends on the intake and exhaust system you are running, how well your injectors are flowing, etc. There is a safety margin built into the default PFC map. You may have some rich areas at low load, especially since porting reduces engine vacuum. You've answered your own question in the sense that you need a wideband and you need to do some testing.

Some have reported complete elimination of the 3-4k hesitation that you are referring to. But you will still likely have some tip-in stumbles without retuning tip-in fuel.

You need to get a Datalogit and start logging your boost curves and turbo transition point before you make hardware changes. Make the determination later. There are a number of ways you could implement it in terms of the solenoids and plumbing. You can also go with an external electronic boost controller. Basically, there's not enough information to make this judgment.

Not enough information to make this judgment. You need to supply datalogs taken under something approaching a worst-case condition: basically boosting in a higher gear in cold weather.

ArmitageGVR4

iTrader: (13)

Thanks for the reply! I just finished installing the PFC and re-initialized it / went through the idle learning process.

I've been looking at Widebands and am blown away by how inexpensive they've gotten. I have an AEM in the Galant but am thinking about an Innovate for the FD. Any preference over the older LC-1 and the all-in-one MTX-L (similar to the AEM UEGO I have but digital like the LC-1).

I'm going to do some road testing now and will capture some logs to look at the boost/transition with the MBC.

Thanks!

arghx

iTrader: (3)

If you're looking at widebands, find something that uses the LSU 4.9 sensor .

ArmitageGVR4

iTrader: (13)

I can confirm that the 3-4k hesitation that was especially bad after the double throttle elimination is completely gone.

I was having some boost control issues with the new turbos so I yanked the MBC and re-installed the original lines w/restrictors. Things seem good now I haven't gotten any logs yet; this is not a good time of year to be on summer tires when the secondary kicks in.

arghx

iTrader: (3)

ok, keep us informed. what are your boost settings in the PFC, since you are using the stock solenoids and hoses now?

ArmitageGVR4

iTrader: (13)

I'm using low boost settings at the moment for fuel cut in the case of overboost (.70/.65 IIRC, I haven't calibrated the MAP sensor yet). I've got the solenoid connections on the PCA and WGA capped so I'm running just on the springs. 7psi creeps to about 11 when the second turbo kicks in. I'm going hook up the solenoids this weekend and see if I can get to a stable 10-11-10 or so. Still kicking myself for not porting the wastegate when I had the chance.

cewrx7r1

iTrader: (2)

The old 3K stumble was the worst Mazda ECU programming error.
The M2 and Pettit reprogrammed ecus helped it some but some times did not help it at all.

Only the PFC is known to totally solve the problem.

Double throttle elimination does not cause the 3k stumble.

arghx

iTrader: (3)

Yeah, in the old days there was no way for dealerships to reprogram the ECU quickly and cheaply. So a fix for the hesitation must have come later.

ArmitageGVR4

iTrader: (13)

Got my solenoids hooked up today and did some testing on the road with about 40 deg outside air temp. I had my "Boost Control" set to .70/.70 with the default duty but it seemed to want to overboost, so I dialed it back to .65, then .60, then .55. It didn't feel like the changes were making any difference; boost seemed to hold pretty steady in 2nd gear, but 3rd it hit fuel cut at about 12 psi indicated on the gauge which correlates to the .70 setting I started out with.

So that brings up my first question: when you modify the "Boost" setting and click update, do you have to key-off/key-on for it to take effect? The reason I ask is because after dinner, it never overboosted on any 3rd gear pull and held pretty rock steady at an indicated 11 psi. The transition looks/feels pretty solid right out of the box too:



Another question: what good is the "Advanced Boost" metric for? I can't correlate it to any units that make sense. PIM is a pain in the *** to convert but at least it's useful.

I've attached the log but I don't think there's much to do until I get the WBO2. I am concerned with seeing as much as 140 knock just cruising around. Either the sensor is busted, my car is too loud, or the whole thing is just worthless to begin with. Regardless, except for the weird overboost that was happening earlier, the car is running much better than it ever has before!

Thanks for the help, I really do appreciate it!

arghx

iTrader: (3)

You attached the map, not the log. The map is the .txt file.

this post (which is referring to a single turbo application) gives some hints about adjusting target boost vs duty cycle setting https://www.rx7club.com/single-turbo...ontrol-900599/

you'll have to play with primary vs secondary setting, and you've got the transition point rpm settings that could be adjusted as well. It just takes time and experimentation. Every car is different because of differences in plumbing, exhaust restriction, porting, etc.

ArmitageGVR4

iTrader: (13)

I've read and re-read your posts there and have been playing around with my setup all week. I've got what I consider to be a good handle on it now. Reducing the "boost" settings for Primary/Secondary didn't do anything for me at all; I was still spiking to 12 and hitting fuel cut (set the values to .50). But after lowering the duty cycles I'm now rock solid 10-7-9 without any hint of spike. Now just to raise up the secondary a bit to smooth things out and I'll be in good shape till I get the WBo2 for some real tuning.

Thanks for all the helpful info here and there. I'm psyched that I'm not overboosting anymore and can control boost with such precision without any aftermarket controller!

ArmitageGVR4

iTrader: (13)

Decided to try and calibrate my stock MAP sensor this weekend.

The first thing I did was try and achieve 0 PSI (~10300 kg/m^2 PIM) with the engine off. On normal setting, I had to set the offset down from 3947 to 3500 to achieve this.

Next, I tried to calibrate it to 10 PSI. I had to get the offset to 3000 to achieve that.

I picked a point in the middle at 3250 and then played with the Scale but was unable to get it to a point where it was accurate at both 0 and 10 PSI. So I set it to default scale and 3000 offset and let it rip.

The car feels fine just about everywhere under load now, but idling and as soon as you let off the pedal and it runs so rich it's popping and backfiring everywhere. So...

Do I need to keep trying to adjust the Scale? Put the Offset back up to where it was? Re-initialize the PFC and go through the idle learn process again?

Thanks!

ArmitageGVR4

iTrader: (13)

Another thought I just had. I calibrated the sensor with the key on but the engine off. Would calibrating it while running off the battery (12 volts) vs what it sees when the engine is running (14 volts) invalidate my results?

arghx

iTrader: (3)

Are you trying to calibrate the MAP sensor to address an idle problem? I don't understand what your purpose is. What was the condition of the car and tune before you adjusted the MAP sensor scaling?

cewrx7r1

iTrader: (2)

It is so easy to test, do it instead of asking.

ArmitageGVR4

iTrader: (13)

The intent was to calibrate it so that datalogs represent boost accurately.

cewrx7r1

iTrader: (2)

I have calibrated a few map sensors, stock and 3 bar. You can not get them to be 100% accurate from just turned on and not running to full boost.
Thus I do mine to be accurate at full boost.

I use two pressure regulators and a very accurate 0-30 psi pressure gauge along with some EXCEL software to figure out the most correct scale and offset to use.
Look at the yellow heavy line with the thin black logged data points on it.
After doing this you go back again and test/log and then calculate boost from the pim and see if it is all correct.

If you are a member of the YAHOO PFC Tuning Group, this and more are avaliable. Contact arghx.