Tuning my DR750s on Chrome

[Chris@Rvengeperformance]

First some basics about my setup:

DR750s
ETS Fmic
FIC 1050 low impedance injectors
Hallman Pro MBC
Walbro 400 e85
HKS DLI
MSD Wires (stock boot style)
NGK 4091 Gapped to .025
stock new fpr
Ninja performance fuel pump hotwire
3sx fuel rail loop
stock fuel lines + filter
Stock Manifolds, front is welded and ported
DN Precat eliminators
Tanable Knockoff downpipe with cat delete
Tanabe Touring Medallion Catback
Evo Maf + Huge K&N filter
Chrome 2

I think that is about it in terms of power or supporting mods.

The first thing I did when installing the 1050s was get the fuel trims decent working with the injector sizing and injector battery latency tables. I also had to work quite a bit on the startup tables to get it to start in all conditions. I think began getting the tune reasonably close for WOT. I tend to use a hybrid approach of getting the global fueling close using the injector sizing, then getting ranges close using the VE/MAF table, then I fine tune the fuel map.

First with pump gas and ~15 psi peak:



Afr was fat, but the point was really just to get a safe decent tune for 93, max power wasn't the objective. Having done that I ran the gas tank down to the fuel light and added 5 gallons of e85. I did that so I wouldn't have to worry about tweaking the tune at the gas station. I took my 93 tuned injector size and times it by .7 to get started. The car fired, ran really rich for 30 seconds or so while the gas got pumped out of the fuel lines and injectors, then it ran pretty well. Well enough that I ran over to the fuel station and just filled it up.

Car actually ran decent enough. I did some daily normal driving to adjust the global injector size slightly, but it really wasn't far off to start with. Once the trims were decent enough I started doing some WOT pulls in 2nd. In my particular experience my car always runs about .5 afr richer in 3rd, so 2nd is a good place to start.

Here is the first WOT 3rd gear pull, again at 15 psi:



At this point the afr was getting fairly dialed in. The issue I had is the stock BCS solenoid is not great for trying to run much more than 15 PSI, even with the upgraded wastegates it just couldn't bleed off enough air. Greg has a few solutions for this, but with the days until the gathering getting closer I decided to keep things simple and run the hallman mbc. Obviously compared to the ecu based boost control it is very primitive and I intend to switch back at some point, but it works well for now.

I turned boost up to about 24-25 PSI in 2nd and ran into some ignition issues. There was some breakup around 4000. I was running the ngk 4091s gapped to .030. I wanted to try the champion surface discharge plugs, so I swapped them in. Immediately I had misfiring at practically any boost (like 2-3psi), so I swapped back to a new set of ngk 4091s gapped at .025 and it cleared up.

I ran some 3rd gear pulls today and hit the same breakup around 4000 RPM. I turned the boost down about 1 turn on the controller and after some afr tuning I had this:



That is about all the boost I can run without breakup. Afrs are pretty decent and safe. Ignore the boost on that graph, it reads a little low. It was in the mid 80s today, so a little warmer than the previous tunes.

At this point I need to resolve my ignition issue and run some more boost. I have not touched the timing map, it is on stock timing. I'm sure there is power to be had there, but I want to let the boost do the talking for now, especially since on e85 by the time I see a lot of knock it'll be too late. The current tune hits 1-2 counts on occasion, interestingly about where the breakup was, so they may be ignition related.

The coils and ptu are not very old, I have msd plug wires, so I am not sure what could be the issue. Anyone out there with ideas? I will replace anything necessary, but I do not want to replace anything that is good.

I would like to run 4-5 more pounds of boost and get around 550.

[CoopKill]

In for info!

[Ninja Performance]

That is a serious power curve. I KNOW that car is a blast to drive!

-Chris

[Chris@Rvengeperformance]

Thanks Chris! Pretty much instant boost anywhere above 3K.

This can kinda illustrate the repeatability of the virtual dyno:



After the 1st run I raised boost .25 turns. They were not even on the same stretch, but you can see how close the curve matches up.

[J. Fast]

10 degrees at peak tq and 18 at redline? Since those spool so early you can likely light it off even earlier... maybe even 8 degrees? Where's your arc signature on the spark plug strap?

[Chris@Rvengeperformance]

10 degrees at peak tq and 18 at redline? Since those spool so early you can likely light it off even earlier... maybe even 8 degrees? Where's your arc signature on the spark plug strap?

100% stock 99 vr4 timing map:

2687.5 21
2718.75 19
2750 17
2781.25 16
2812.5 15
2843.75 14
2875 13
2906.25 12
2968.75 12
3000 12
3031.25 12
3062.5 12
3093.75 12
3156.25 12
3187.5 12
3250 13
3312.5 13
3406.25 13
3406.25 13
3468.75 13
3531.25 13
3562.5 13
3625 12
3718.75 12
3750 12
3812.5 11
3875 11
3906.25 11
3968.75 10
4000 10
4093.75 9
4125 9
4187.5 10
4250 10
4312.5 10
4343.75 10
4437.5 11
4500 11
4562.5 12
4625 12
4687.5 14
4750 15
4812.5 16
4843.75 16
4906.25 17
4968.75 17
5000 18
5062.5 18
5187.5 18
5187.5 18
5312.5 18
5312.5 17
5343.75 17
5406.25 17
5468.75 18
5531.25 18
5562.5 18
5625 19
5687.5 19
5750 19
5781.25 20
5843.75 20
5875 20
5906.25 20
5968.75 21
6000 21
6062.5 21
6093.75 21
6125 21
6187.5 21
6218.75 21
6281.25 22
6343.75 22
6375 22
6437.5 22
6468.75 22
6500 22
6562.5 22
6593.75 22
6625 22
6687.5 22
6718.75 22
6750 22
6781.25 22
6843.75 22
6843.75 22
6906.25 22
6937.5 22
7000 22
7000 22
7062.5 22
7062.5 22


I have not pulled the plugs yet, maybe tomorrow.

[Chris@Rvengeperformance]

Anyone with much e85 experience have input? Is 11.5 AFR a lot harder to light off than 12.0? I was trying to produce a safe tune, but if leaning it out will give me some ignition headroom I will.

[wingnut]

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[Chris@Rvengeperformance]

After looking at the video the boost logging I have setup isn't off nearly as far as I thought, maybe 1 psi, so I'm not running quite as much boost as I thought, only about 20-21psi peak and maybe 18 at redline.

Good though, because there is a lot of room to go up.

[TurboSinceBirth]

When I ran 10s AFR it would break up badly. I honestly don't recall on low 11s AFR since it has been awhile probably last Sept when I first started tuning with ethanol. I found my car liked 12.0 AFR WOT really well. You could feel the torque increase and engine run much smoother. I hit 14s WOT at the track due to a spike/issue with the MAC solenoid not ramping up the boost to my target correctly which sent me 20+ counts of knock which luckily didn't do any damage. I put probably 600 miles of WOT 2nd through 5th pulls since then at high 11s low 12s without any issues. The only time I would ever get knock is if I had a vacuum leak causing a momentary lean dip when building a few lbs of boost on light throttle. I would give it a shot leaning it out since it may help your stumbling issues.

I'm running the #8 non projected tip plugs instead of the 7s you have so there shouldn't be any issues there. I had mine set for 0.028" gap before the DLI at 24 psi on new OEM coils, PTU, and MSD wires. I left the gap the same after installing the DLI to turn it up further. Honestly, I don't know how to check if yours is still working correctly. I've never had one fail but it could be an issue. I would at least check the primary and secondary coil resistances to see if they're within spec. These cars are finicky and really do need a fairly new/excellent ignition system. I've also had severe break up/missing when I wasn't getting enough fuel due to a loose fuel pump hose on the hangar. I couldn't get into any kind of load though and the car would idle super lean 16-17 AFR so I don't think you're having a fuel related issue.

I will be curious to see if you do in fact have an ignition issue that gets fixed what the champion plugs will do again since that could have been related to your ignition with the plugs amplifying the previous issue. Whenever I get my car back together I want to give them a shot.