Discussion: ECU Tuning, Water/methanol injection, and VCT tuning on a VH45DET

[qsiguy]

I found some info in the consult data register so I labeled the Consult register data table for the VH45DE. Thought this might prove useful for some.

[tmorgan4]

Nice!!!!

[qsiguy]

Here is a short demo video of my Map trace. As you can see my TP goes up to ~100 and the TP Scales only go up to 72. The ECU keeps the same values for every load area above 72. I am going to expand the TP Scales to 128 and the RPM scales to 7200 RPM. That should allow me to perform some precise tuning with a little head room for a tad more boost.

[qsiguy]

Here is a screenshot. Now that I see this I know that nearly all of the changes I did to the fuel and timing maps were pointless. The TP isn't even hitting most of those spots on the map at WOT.

[qsiguy]

I got the RPM and TP scales expanded. Too late to go for a ride now but I'll give her a road test tomorrow. I did burn the new chip and idled it in the garage for a bit and it still started, which is a good sign! I have a screenshot of the new expanded map trace map but you'll have to wait to see it, Photobucket is down for maintenance at the moment. Tomorrow I'll have a new expanded video for you to check out.

I'm so excited to be making this progress now, it's like Christmas!

[John Dixon]

Good stuff! Glad you're getting somewhere

[Carl H]

lol, it doesnt really suprise me that you were hammering the far right coloumn due to tp, i would have remapped the tp for boost.

[qsiguy]

Now you tell me! Actually I assumed that was the case but I had no way of knowing what was happening without map trace or at least knowing the TP value. It's a whole new game now.

Car ran good on the way to work today. Still had a little detonation but I haven't really changed anything yet, just expanded the scales. On the way home I'll fire up the map trace and locate my problem area(s). I love it!

Now all I need is real time tuning so I can stop swapping chips.

[SSDwellah]

By the way, I have some address values for the 8-bit VH45DE ecus from when I was working on a tuning software. If you want them I can post them when I get home.

[Carl H]

you should consider pulling quite a bit of timing out of there as even nissan turbo cars dont run that much timing at ~7psi.most i've seen is 25* at 8psi on a stock motor w/ 8.5:1 cr.

[qsiguy]

Definitely post whatever you are willing to share. I'm trying to gather as much info as possible.

Carl, the screenshot above is the fuel map IIRC. I'm definitely not running that much timing. I'm sure some areas of my timing map are above 25* but not where I'm getting detonation. You think I should lower timing across the board for everything over about 60-70 TP? That's about where I'm hitting about 7 PSI or so.

[deviousKA]

qsiguy, where in the world did you obtain the data register table you posted for the Q45?

I ask this because it looks as if it is factory provided data, in which case I would crap my pants. Even for a complete set of oem consult documents that seems odd they would list the ram variables.

This table is easy to find in the code, and is the way I located the rpm msb/lsb, it looks accurate btw. You can add any ram variables to unused register locations and stream them using the 5A command. Any time you make a custom set of consult registers you need to make custom software to interpret it properly though.

Does Robert Bowen still work on Q45's or no? Did he leave you guys any of the data he worked out? Ive never really spent much time on the Q45, just disassembling the other day to find those ram variables, but I am thinking of adding a section on eccs.hybridka.com for these. I am interested in writing some code mods as well.

[qsiguy]

I made the consult register table in excel from the table I have in Tunerpro. The descriptions I added were found from the following document.

http://www.obdiidiag.com/downs...2.pdf

They have quite a few interesting documents here as well...

http://www.obdiidiag.com/downs1393/

I read an article about using an unused address to add the TP value to the NDS data log. The O2 Sensor RH gauge was used for that value as it wasn't used on the vehicle. It was a Nissan Altima. jserrano wrote it, who's also a member of this board, great writeup. I am extremely interested in anything I can learn about tuning this, and any other ECU. I'm addicted to information!

Robert got out of the ECU business after he sold his Q45. I was in line to take over the NICO ECU's but Wes ended up getting all of Roberts equipment and information and is working on that project now.

I'm surprised that more work has not been done on the VH45DE ECU's with all the swaps being done. I guess most are just using stock ECU's, Megasquirt, or something else. If you decide to do some work with these ECU's I'll definitely be right in the middle of it soaking it all in and hopefully providing some assistance!

Thanks again for help you've already provided for my project, huge help. I didn't know you were a member of NICO as well.

[qsiguy]

Did a bit of logging at lunch today. Here's a screenshot of the expanded map using map trace for a 2nd gear 40mph roll run. Ambient temps were in the high 90's and I'm using 91 octane fuel. Tune is really rough after expanding the maps and still just getting a bit of detonation in the same area, 4-5K.



Also, here is the wideband log from the same run. Looks like I'm running a little lean so that's what I'm going to focus on first. I don't think my timing is too advanced, do you guys?

[Carl H]

afr looks fine, just remember that there are two tp scales, one for fuel and the other for timing.

[qsiguy]

I know about both TP scales, I expanded both of them and they are the same. I'd like the AFR a bit lower above 4k since I have to use 91 octane and also because, for the time being, I don't have an IC. My bigger concern is from 3-4k. I'm in boost in that area and it's pretty lean. High 3k range is where I'm seeing detonation begin.

I made a few tweaks last night to the fuel and a bit to the timing along the TP graph. This afternoon wen it's nice and hot outside I'll see if I made any improvement.

If those AFR's look good to you and you were getting detonation in the 3.8k-4.8k range what would you be working on? Just keep pulling timing until it cleared up? So I'm clear, base timing is 15* and the map numbers are advancing it even further? So if the map timing number was set at 0 timing at that spot would be the base of 15*, or if it's set for 15* the total advance would be 30*? Am I understanding this correctly or have I been assuming wrong all this time? BTW, the map trace screenshot above is the timing map.

[Carl H]

timing is based purely on the map, so if the cell says 15* it is 15*, this is why most of the time base timing is set dead center of the cas with +/-15* adjustment for streched chains/timing belt.with a high CR like that, once you hit full boost you proly should throttle back timing to no more than 25*, but this is dependent on the setup...afrs are ok but since you're non intercooled, even with methanol/water its still rather agressive timing you're pushing.just keep pulling timing till knock subsides.

[qsiguy]

Thanks for the explanation. Right now my timing is 17-18 throughout the knocking area. How far do you think I should retard at a time? 1-2* or 5-6*, etc? What timing values are typical in the full boost areas of a map? How much timing would you pull before looking at possible other issues/causes?

[qsiguy]

Well, just got back from lunch and did some driving around. It's much better now. Noticed no knock at 4k and I'm not sure but I think there was just a tiny bit up around 5K. Last night I pulled a degree or two of timing in that area and added fuel. Much better now.

Getting closer...almost time to get it on the dyno and see what this baby can do and hopefully get a bit of tuning time while I'm at it. Need to get an emulator prior to that tho.

[deviousKA]

What sort of ecu controlled emission equipment is used on the q45? Is there an aiv or egr system? egr sensor?

You can do just about anything with these ecus, the q45 rom looks really packed though so the first step is identifying potentially unnecessary functions so that the resources can be reused.

[qsiguy]

There are a few on here more knowledgeable than me as to all the components on the motor but there is an EGR system, Idle Air Control/AAC control valve, prob. other items. I'd have to look at the ECU wiring diagram and see what's being controlled that isn't a necessity if you are willing to sacrifice a few items.

Robert Bowen theorized that you might be able to use the EGR valve in place of a wastegate to control boost. Not sure how he intended to go about it tho. I don't think it would be too difficult to control the EGR to open under a set boost but I don't think you'd want it blowing into the intake manifold under WOT/full boost conditions. Interesting concept but I'd have to learn more about it.

[qsiguy]

I made a few changes to my tune and will be testing it tomorrow. I decided to change the VTC set point to 3900 instead of the stock 4600. I haven't been able to find any documentation on anyone testing changing this value on anything with boost and reporting results. I read on a tutorial on hybridka where the author dropped this value on the 300ZX turbo from the stock 5900 to 4900. I'll let you know the "butt dyno" results.

I also tossed my "bleed style" boost controller I made and installed a pressure regulator feeding the WG top port. The old one was working fine but I wanted to get rid of the boost leak, make it simpler to adjust, and hopefully keep boost drift to a minimum. With the old one it would change boost by ~1-2 psi from morning cool air to the hot afternoon air, 90's currently.