One area I'm still having issues is a slight detonation around 4K and 5K. I kept retarding the timing in several areas on my first tune and eventually I could tell I had lost a lot of power from taking out too much timing in too much of the timing map. I took what I learned and started fresh with my original tune and just added fuel and retarded timing where I knew I needed it. This tune is pretty good and restored a lot of power but I still have the slight detonation at 4k and about 4.8k rpm. AFR's are good in the 11.5-12.5 range depending on RPM/load. Best pump gas here is 91 octane. At WOT and max RPM (around 7K) I'm at about 82% duty cycle on the injectors at ~7 PSI boost.

QUESTION:

Do I just keep pulling timing in the last couple columns of the map in those RPM ranges until detonation is gone? I'm up to -7* and -8* under my starting map in the areas in question. Is it normal to have a small spot around 4k or wherever, that requires timing to be that much below the surrounding blocks?

or do I...

Leave it and install the water/methanol injection system I already plan to install? I originally was hoping to get a good tune without the water injection so I didn't have to rely on it but am I wasting my time? I'm pretty confident the water injection will eliminate the detonation and probably allow me to increase boost to a solid 8 psi, which is about as high as I want to go without modifying injectors, MAF, etc.

or...

Will modifying the VCT rpm on/off points do anything for me? Stock is 4600 rpm for on/off. The aggressive tunes Robert Bowen made for the "NICO ECU's" use 4200 rpm for on/off points. Does anyone know details of this system and benefits/drawbacks of adjusting the switch points high or lower? Anyone tried tuning it with success/failure that can share experience? If not, I might try lowering it to around 4k to see what it does. I wouldn't think it would harm anything, thoughts? Maybe it would help my detonation issue at 4k? Unfortunately I haven't found any information to tell me if it can help my tune or not. I'm sure there are beneficial adjustments that can me made to it, I just don't have any idea how.

I think its probably a fuel issue because I didnt think Siju was having these problems.. It still may not be a bad idea to install a rising rate FPR... I wonder whats actually happening.. That is around the peak torque and HP of the motor so of all places that would seem to make sense for detonation to occur..

Are you running lean in those areas? Id really like to see it run without methanol because I think it can be done, seems like going right to the methanol is sorta like taking the easy way out, just my opinion.

I suppose just for grins you could move the VTC point, however when VTC is on it advances the duration of the valves and also increases overlap. Also take in mind that it only does the intake cam, so as I understand it all your doing is making the intake valve close later.. Overlap works great in N/A but not so well in turbo motors..

Take that as you will, im not sure if you'd want to make the VTC on sooner or later, or if it would make much difference at all.

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I've got my car tuned for ~ 11.5 (between 11.2-11.8) under full throttle. My water injection kicks on at 4 psi. The base timing is set at 15 degrees. The car moves like you wouldn't believe for a 2 ton beast.

Next question....

Should I just start with water or go right to the methanol injection? I don't believe I have a lean problem so really I think I just need to cool the intake charge. If I do have a lean problem that's easy to fix in the fuel map.

BTW, already planning the IC, just need to find some money in the budget. There is also still a section of the charge pipe that needs to be wrapped to keep heat from one of the cats off it.

Hey Siju, What octane fuel were you using? 91 or is 93 available in Oregon?

Modified by qsiguy at 1:33 PM 4/15/2008

I tuned the car without water injection just to be on the safe side. The water injection is just there for insurance but the car didn't detonate without it. In Oregon, they have 93 octane which, up to last month, didn't have any ethanol but now the good times are over with ethanol in the fuel now.

When I was in California, the car ran good under boost with the 91 octane but I was spraying water so that has a tremendous effect.

I agree, it's a blast to drive and quite a rush. I need new rear tires, even with my OEM rear diff still (4.08 install pending) the rear tires will often break loose even up around 20-40 mph if I'm already moving. Took my wife out to dinner on our anniversary and she got a little nervous when I did a little demo for her. She hasn't really ridden in the car since it got the turbo. I think it was the "fish tailing" it was doing for about 30 yards that she didn't like. She was reaching for something to hang on to

I ran a 1/2 tank mix of 100 octane and 91 octane and it didn't detonate at 6 psi with everything stock, ECU, fuel pressure, etc. I'm sure at 91 octane the water injection is making all the difference.

Water injection is a proven method that has been used for decades. Since you live in AZ I doubt you ever worry about freezing, but just the same tune your water injection for windshield wiper fluid. Its a good mix of alky & water, easy to find, and if you ever drive to a climate where freezing is a threat, you won't freeze the water and break things.

Just keep a close eye on the fluid level

Modified by rhinoone at 10:42 AM 4/16/2008

I was just looking at the other options at the hardware store tonight and to me it's a no brainer. The wiper fluid is premixed, cheap, and safer than some of the other chemicals, with the exception of water. Some of the other options were over $6 for a little can. You can get wiper fluid for < $2 gallon.

that is one nice climbing dyno there. Can you imagine that powerband w/ 5spd in Z32?

tt right? Are you the guy on Propane?

I pulled my pass. headlight out last night to work out a way to plumb my meth injection from that reservoir. I think I will just drill a hole in the filler neck and feed a 1/4" tube down into the washer reservoir. Thought about putting some sort of fitting on the bottom but I have a feeling I'd just be asking for leaks. It's so old it may just crack anyway. I think through the top is the way to go. Just need to set the pressure on my pressure switch, test the pump with the injector and the length of tube I'll need and if it all works get it installed. Should be pretty straight forward. I have a dual stage boost switch inside the car so I will be wiring it so that when it's on stage 2 and boost hits 4 psi the meth injection starts. Stage 1 boost is just the wastegate spriing which is 3.6 psi where I don't need the injection.

I did also decide to richen up the AFR in the trouble area instead of pulling more timing to see if Wes was right. I haven't tested it yet. I'd like to see if I can get the AFR down to about 11.5 across the RPM scale at WOT especially when I hit 4-5 PSI which is around 2.7-3K rpm from a standing start. Already rolling it's lower, around 2.2-2.7K rpm. Started the meth injection install so testing this new tune will have to wait.

If you can afford some time on a dyno that would be your best bet for getting a safe tune. Without a dyno it's really hard to tell if you have ideal timing or if you could possible back it off a bit to gain a bit of safety margin without sacrificing any measurable power. The same goes for the AFRs. If you can run it at 11:1 instead of 12:1 and still get about the same power then it's worth running the extra fuel just to keep things safe.

Are you using Nistune?

I'm currently using the wideband software that came with my Zeitronix WB sensor. For the consult stuff I use Nissan Data Scan and ECUTalk. I prefer ECUTalk for the logging but NDS provides some options ECUTalk doesn't.

I should have the meth system installed in the next few days and then I can test my most recent tune. I backed off a bit more timing around 4k but mostly I lowered the AFR's in the last couple columns and more so in the 4-5K area. Hopefully that will do the trick w/o meth. Regardless I think I'll start tuning with the meth once it's installed and I test this current tune.

EDIT:
Interesting reading on the VCT but if I read it correctly those tests were done NA and not boosted. Is this correct? I saw he posted the stock timing map on another linked thread from the one above, any chance he posted his tuned maps anywhere? If anyone knows I'd love to see them.

Modified by qsiguy at 2:06 PM 4/17/2008

I dont think I ever posted the finished timing maps. If I remember correctly we added quite a bit of timing in the higher rpm areas. to help bring up a dip in power. I'll see if I can dig up the map but its been a while.

I got the methol injection done. I posted the details in the Q45 forum at this link http://forums.nicoclub.com/zerothread/331064 . It's made a huge difference. It got rid of the detonation I was having and I've even advanced the timing a bit where I had pulled it, still with no detonation. I've also increased boost to 8 PSI. I love it!

Here are some images that shows the difference from my current tune vs. stock. The timing is just pulled from 3.6K to 4.8K rpm in the last 3 columns. No detonation noticed so far up to 80-90* ambient temps. The fuel map you can see I've just added fuel in the last two columns just about over the whole RPM scale. There is no picture but I also had to tweak the high gear fuel map a bit in the cruise rpm/load area to keep it in closed loop while cruising.

Timing map difference from stock. You guys think I should advance more now that I have the meth injection?

Fuel map difference from stock

I've been trying to calculate the TP #'s so I can plot the maps and here are the results of my number crunching. IF the formulas and numbers are correct this chart shows the potential detonation area (mostly the center of the orange). I had been pulling timing in the far right columns assuming thats where it was at. Seems to me the load would be higher at WOT and full boost. Anyone have any knowledge of this? I guess it wouldn't hurt to pull some timing in that area and check the results. According to these numbers you'd have to be on a pretty steep grade WOT and pulling hard to get to the right of the map...but I guess that makes sense now that I think about it. Flat ground acceleration wouldn't be that huge of a load compared to what the car can pull on a hill or something. Hmm..

This data is from a log of a 40-65mph pull in 2nd gear and I DID get detonation/knock ~4K rpm even with methanol. Also, if this load reference is correct I may need to retune my fuel as I was also changing those numbers in the last two columns as you can see above. I may just start from scratch again with a tune. Each time I do one I get a little better and learn a little more.

[EDIT: These are NOT the right calculations!]

Modified by qsiguy at 11:46 AM 4/22/2008

Modified by qsiguy at 4:20 PM 4/22/2008

Definitely NOT the right calculations! I lost my nice AFR. The TP is for sure on the right side of the maps if not all the way to the right side columns. Went back to previous bin and made more timing tweaks. I'll have to check out the next tune after work.

I want my own dyno to tune on I'd be happy if I could figure out how to program Nissan Data Scan's map trace to work with my ECU. Need to find some technical support for it. Then I could tell where I was on the map.

Nistune looks awesome but I don't see support for the VH45DE. Do you know if they support it or not?

The only issue is that you have to use an emulator because the stock rom is too small to hold the extra code that the Nistune hardware requires. It sounds like you already have an emulator and a consult adapter so all you need is the software.

The nissan datascan maptrace works but completely sucks *** as far as usability.

Nistune allows live tuning, live map trace, cell highliting, and plays back the trace when you play back the logs. The cell highlighting keeps all the cells that the ecu has used highlighted until you clear them. So you can do a pull and see exactly which cells the ecu used and know exactly which cells to change. Or if you're holding a load on teh dyno you can sit there and change your timing and watch the power output change in real time. It'll also make swapping injectors and mafs a lot easier if you decide to do that. Well worth the money.

[EDIT] Ok so I keep going back and reading information on the Nistune site. I'm trying to fully understand how it will work for my ECU. Since I have to use an emulator, I cannot use the Consult connector to tune, correct? If this is correct, does the Nistune software have realtime support if used with an emulator through the USB or Serial connection?

Modified by qsiguy at 3:57 AM 4/24/2008

The emulator takes care of changing the contents of the chip and consult takes care getting the live information from the ecu. Normally they would be independant of each other but Nistune brings them together in one piece of software.

I use the Romulator with a Serial-> USB adapter with no problems. USB or serial consult should be fine. All you will need to do is tell Nistune the com port number for the device.

With the help of deviousKA on the hybridka.com board I now have the correct addresses for map tracing with NDS! I still need to drive it to verify the numbers look good but in park revving it looks good.

This is for the VH45DE pre '94 8-bit ECU's. The '94 and up ECU's are 16-bit and I don't know if these will be the same for that one.

Primary Timing (No Knock)
RPM MSB 140B, Map Address F800
RPM LSB 140C, TP Scale Address FB10
TP MSB 148C, RPM Scale Address FB20

Primary Fuel (No Knock)
RPM MSB 140B, Map Address FD00
RPM LSB 140C, TP Scale Address FAF0
TP MSB 148C, RPM Scale Address FB00

These numbers are are actually the same as the VG30DETT except for the RPM MSB and LSB.

So next thing to do is extend my TP scales and then I can get this baby tuned properly! You can't imagine how relieved I am getting map trace working. Awesome!

I made a little video of the map trace working, I'll post it in a bit.

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