I was attempting to adjust the starting map the other day and the rtek decided to reset itself back to stock. I hadn't saved my map, so I am taking this opportunity to start from scratch and use a calculated approach instead of just guessing and watching afr's. I wanted to get your opinions on my #'s and plan of attack:

I am using the 550/720 setting and my injectors came back from cleaning flowing 576/708. Just accounting for the variance in flow would lead to a correction factor of approx -4.5% for primary only operation (below 3.3k for me) and +1.7% for secondary only (never happens, but...). Since the primary DC is halved I would imagine that using a correction factor of -2.5% would be appropriate for the >3500 rpm areas. This is all assuming stock fuel pressure of 38psi.

I have actually raised fuel pressure to 43 psi and according to my calculations should use corrections of -9% and -5.5% respectively.

These numbers would only be applied below 6psi and would decrease (inject more fuel) as boost rises. I had previously removed up to 7.5% from the vac/ cruise area of the map (1500-4000 rpm / 24in/hg - 0psi) and noticed a boost in performance. So it seems reasonable that similar settings could improve the positive pressure side of the map as well.

Stock ports, stock turbo, rewired FD fuel pump, areomotive FPR, stock timing (for now...)

 

sure that method, generally, works pretty well. actually 2 or 2.5% is a good number too. i'd pull 2% and see how the car drives+afr, pull another 2%, recheck, etc.

actually this is a good tuning method, once you know how lean you can go, and how rich you can go, in a given RPM/load than tuning it is pretty easy.

for example on my P port, the factory jetting (from the comp book) @2500rpm cruise was richer than 10:1, and i leaned it out to like 15-16:1, and i found that it is happiest in the 13.5-14.4:1 range, so that's where i have it.

its an extreme example, because the stock engine tolerates a wider range of AFR's but you get the picture, nes par?

 

Gotcha.

I figured I'd start by running some logs w/ the map 100% stock since (in theory) it should run rich, perhaps richer in some areas than others. The results were ....interesting. One log where I rolled onto the the throttle in 3rd or 4th showed 10.5 afr @ 8psi until the secondaries came on and it jumped to 15.96 @ 9 psi. It began dropping slowly (eventually getting to 14.6 afr @ 10 psi) but I got out of it for obvious reasons.

Another log in either 1st or 2nd showed 12.72 afr @ 2 psi....then the secondaries come on and bam! 17.5 @ 3.5 psi. Wtf? It eventually comes back down to 12.8 @ 7psi. I could have sworn the secondaries were supposed to add fuel, it seems almost like they are taking it away.

 

weird, its almost like they are not working?

i looked at the math, and per rotor, on just the primaries we agree, 4.5%, per rotor with BOTH injectors running its a 1% difference, so maybe fuel is lean?

 

Just finished the cruise area of the new map. -9.4% between 3k and 3.5k tapering down on either side.

I guess I will just use the -4.5% where applicable and add 5% to the areas w/ both primaries and secondaries to see if that helps. It'll be a start at least...

 

You are using resistors with the secondary injectors? Is it a stock resistor pack or did you wire them in?

 

The resistor pack is 100% stock. I rewired the fuel pump with 10 gauge but retained stock voltage dropping relay package, it had been relocated to the rear near the pump.

The secondary injectors are denso blue top "720's" which are low imp according to my research.

 

Re wrote the whole map. Went for a test drive.

Pulls smoothly in high load - low rpm situations (mid 10 afr). High load-moderate to high rpm it leans out and stumbles (13-15 afr).

There's no way a stock turbo needs more than +5% fuel below 10psi so I suspect one of these secondaries is acting up again....may be time for some replacements.

 

My car did that. I corrected for it with my AIC that was on the car when I bought it. I adjused it to bring in the additional injectors at 3 -4 lbs of boost. That smoothed it right out. Brought my AFR down from 13 - 16 and stubling during the transition to 10.5 - 11.5 and smooth during the transition. I'm just making use of this old stuff that came on the car.

 

What turbo? What injectors?
I've tried tuning around non-working parts before, its a bad idea and I won't be going it again. The ecu is expecting to see 720cc secondaries @ 38psi what its getting (supposedly) is 708cc secondaries @ 43psi WITH a +5% fuel correction @ 0psi that steps up to +10% @ 14psi. Considering how rich the stock map is already, it is completely unreasonable to think that it needs more adjustment (assuming that the injectors are working properly).

 

yeah something is up. my last t2 had 550/680's and i used fcon+gcc, and with the fcon @0 which is "stock" i was actually pulling fuel with the GCC because it was still too rich@stock boost

my neighbor is actually running 550/720's on the STOCK ecu @15psi with a hybrid, and its about right. its enough for him to pull on a Z06 on the freeway!

 

That makes sense, because in both of those cases the ecu is expecting 550cc injectors and is actually getting something significantly larger, so you would need to surat fuel. The rtek has presets for 550/720 so it is expecting 720cc injectors and compensates accordingly so they flow like stock (until u start making adjustments).....that's a good idea. Wonder what will hakeem if I change the preset to 550/550?

 

So I used the 550/550 setting and did a few pulls and it stayed around11-12afr with no stumbling or bucking. Seems a little odd that it wouldn't be richer considering the higher fuel pressure, larger injectors and +5-10% correction factor. Bit I guess its good enough for the time being...

I'll take some logs and try to see if I can tune for 14psi.

 

well think about it like this. the RB exhaust adds 65hp, which is like 20%. going from 4x550 (2200cc) to 550/720 (2490cc) is only 10% so ignoring things like the ECU being able to figure some of this out, the car being on the rich side to start with, BSFC changing, it works out to be close.

in reality i think you can't use HP as a unit, and add it with fuel. we probably should be converting "power" to airflow, and then we can get fuel flow, or something.

since you can, do you have an airflow number? AFR? injector duty? we can get BSFC from that, which is useless... but cooler than trying to fix the stock stereo deck in a vert!

 

Kinda....the 65 hp added by the rev t2 is still on stock 4x550 injectors all Racing Beat did was slap on an fcd. Running 720's as 550's should be dumping fuel --on a stock turbo.

I ran a log of a quick 2nd-3rd pull and a long 4th gear pull. It ran petty well for the most part. The leanest it got was 12.7 @ 10 psi it quickly got down into the 11's afterward. I noticed that the afrs were quite jumpy, even though they stayed mostly in check.

Still not convinced of the integrity of these injectors I pulled them today to swap them...
Low and behold, they were almost completely filled w/ what appeared to be maroon sand!!! This is especially odd since less than a year ago I dropped the fuel tank and thoroughly cleaned it, replaced the fuel filter and the fuel pump sock. Also quite odd was the fact that only the secondaries were plagued w/this foul sediment. In the stock configuration this would seem nearly impossible, as any malevolent particles would have too pass both primary injectors then go up the fuel hose to the secondaries. I am running a parralell flow setup, but it still seems unlikely that the secondary rail would be the only one affected.

Now it makes sense why the afrs were so erratic, and I had to run on the wrong injector setting to keep from leaning out (although honestly I'm surprised they were even able to support 10psi; one looked completely clogged)

I cleaned them out the best I could and look forward to seeing how rich I run now, lol.

 

Cool find and I appreciate you sharing your strategy and results here. I'm about to embark on the same type of DIY rtek tune soon as well and am following your results. That sand is probably the leftovers of any crud that got ground up in the fuel pump but having it only build up in the secondaries is weird. Maybe the sand and fuel are splitting at a 'tee' where the sand keeps going straight, but the fuel makes the sharp turn?

 

Im thinking I must have gone to a gas station that was recently refilled and picked up some sediment from their storage tank, because upon further examination the stuff I found in the injectors is way darker than the sediment I removed from my tank when I cleaned it. I'll open it up again today and take a look.

A far as it only affecting the secondaries, I had that same thought, except its a "Y" not a "T" so it seems less likely....but anything is possible I suppose.

Time to get to work, got a date w/a dyno on sunday and I haven't even set up the boost controller yet.

 

Well, solved the mystery of the "sandy" injectors. Apparently I did not replace the fuel pump sock when I revamped the fuel system because the parts stores didn't have it in stock and I was on a right schedule (read: changing it in the parking lot). At the recommendation of the parts guy I tried cleaning the old sock......worst idea ever! "Cleaning" the sock simply forces the may particles of crap that are suspended in the filter element into the filter to be sucked up by the pump

DO NOT EVER TRY TO "CLEAN" A FUEL PUMP FILTER!!!

So I now have a brand new sock, ran some fuel though the filter and its still decent, pressure tested the system, and installed some new 750cc injectors. Just need to run vac lines for the boost controller and bov and it'll time for tuning.

 

haha changing a fuel filter in a parking lot seems like it would suck royally. Those fuel lines are difficult to get off at the best of times.

curious why you bought 750cc injectors instead of 720cc. I suppose you can never have too much fuel though. also why not just get the 720cc injectors cleaned?

 

Fuel filter was only a 15 min job and the lines didn't give me much trouble at all, I guess fl cars are a but easier to work on, lol.

I got the 750's because they were local and new and I didn't have time to send off the 720's. Also I bought them before I pulled the 720's and found out what the problem was. I have since cleaned the 720's and they work fine, but as you said, can't have too much fuel

 

I bet. When I last changed mine, I was outside in november and it probably hadn't been changed in years.

That makes sense. I'm sure you'll be able to put your extra 60cc's to good use

 

Good news: made it to Rotor Fest 4 on Sunday
Bad news: didn't make it on the dyno

I tried tuning the boost controller (hks evc I) on the highway on the way down but it kept over boosting to 15+ psi. I also didn't finish inputting Arghx's boost based timing map, so throwing it on the dyno seemed...unwise.

After doing some research it seems ebc's don't like being tuned in 5th gear, oops . I did some third gear pulls today and the low boost setting is holding 10psi consistently (although it drops to 5-6 by redline). AFR was low to mid 10's, so there's some work to do there, but I don't want to pull fuel until I get the ebc set for high boost (14-15psi), I also need to finish the timing map.

There's a local dyno event on the 11th of november so I should have everything fine tuned by then...

 

Biggest reason not to tune an ebc in 5th gear on the street is because you probably don't want to be going 150+ mph

5th does load the engine down pretty heavily though, and that's harder on the car. Most aftermarket external EBC's are pretty basic, so you don't have vehicle speed or gear-based adjustments. You just want to make sure that it's not going to start spiking in 5th gear with cold weather. What controller are you using?

 

Well, I was only trying to get the ebc to stay below 15 psi , and it was surpassing that well before even 100mph.

I've always heard that 5th gear puts a larger load on the engine, but my data logs show lower airflow and the secondaries come on later in 4th and 5th.

The EBC is an old school HKS EVC I.