beefhole

iTrader: (29)

I think I'm posting in the right section...

Cliff notes:
did my MSD ignition upgrade make my car run too lean in boost?


Full story:
My car: S4 engine, street port, 8.5CR rotors. TD06-20G, 3" exhaust. Walbro 255, 550/1600 injectors. FPR set to 45-50PSI base (don't recall the exact number on the gauge). 93 octane, conservative timing (I can post more info if required)

My car has been running pretty well for the past 6 months or so. It's all been tuned by yours truly.
During the winter, I tuned for 11's AFR when in boost. I never fully hit the gas because my wastegate is broken, but around 5000-5500 the car really came alive and sent the tires spinning After that I would let off, never going the full 7000RPM.

Just a few weeks ago I installed an MSD6A on the leading coil I had laying around. Eventually I am going to run water injection, it was recommended to have an ignition upgrade.

So the entire winter I was OK with the stock ignition.

It was a beautiful day today, dry and 75 degrees. I took the car out and with a little gas it would start to pick up. Ratios good around 11.5 when hitting boost. As I rolled to around 5000 on the tach (not fully on the pedal), I saw my boost climbing and my ratios were a safe ~11.5:1 when suddenly a little more and I hit 13.5!!! I was at least 10PSI. I immediately let off, thankfully everything was OK. A little later curiosity got the best of me and the same thing happened! Again, I got lucky nothing happened, and drove home normally. I can't say the exact numbers (RPM, Boost, AFR) when everything occurred because I didn't log anything and I was also trying to watch the road I think being only in 2nd or 3rd gear helped...

Do you think the MSD box has effected the tune? Nothing changed since winter except the MSD install. What should I do? The only other thing I can think of is my air temp/fuel map was too extreme, and the much hotter temps were taking too much fuel away. I lowered those a bunch when I got home, but I did not take the car out again so I don't know for sure.

BLACK MAMBA

iTrader: (58)

i just installed a MSD6al-2 last weekend and before the MSD install the car was idling at below 12afr, after the install of the msd i tried to start the car and the car would stall unless i kept my foot on the gas, afr was above 16, had to add more fuel to the base map and the water temp maps, so yes it will affect your map since is burning more fuel. here is a video i made of before and after.

http://www.youtube.com/watch?v=cN-9O...7fAUAAAAAAAAAA

http://www.youtube.com/watch?v=cAL_w...7fAUAAAAAAAAAA

beefhole

iTrader: (29)

Thanks for the input.. That's odd though for me. After the install, it ran a little RICHER, but it idled smoother and the car seemed to start a little better/quicker. But starting was never a problem anyway. Kind of weird also because the rest of the map was fine (and unchanged) but then suddenly it goes lean at much higher RPM. I suppose I could free rev and see what happens too.

Thanks. Any more input is appreciated.

cewrx7r1

iTrader: (2)

First :you never fully got on boost through redline so how can you say those AFRs were good?
You never had a baseline above 5500 rpm.

Second: an ignition system will never directly make the engine run leaner or richer. If it is doing its job better than the previous system, AFRs should go richer as more fuel is burned and more oxygen consumed. Widebands measure left over oxygen.

Most likely you run leaner because you are running higher revs than before and that area was not tuned.

beefhole

iTrader: (29)

During the winter though I did hit those same RPMs, maybe a bit more. There is a "tune" there, but you are correct, I never did hit those areas much. I added 20% to my maps but I have not driven since. I think I will be OK, and soon water injection to save me from myself!