data on which cylinders run leaner than others on 930 engine

[fredmeister]

Does anyone have data or info that they collected on which cylinders tend to run leaner on a 3.3 liter turbo engine with the stock CIS and manifold.
I am installing my injectors which I just had cleaned and flow checked and wanted to try to balance the engine as much as possible. Meaning I would like to install the highest flowing injectors in the manifold location of highest air flow or highest cylinder temp to allow them to run a little more fuel than the rest. This would aid in balancing A/F ratio among the 6 cylinders.
Looking at the manifold I figure cylinders 2 and 5 see the most airflow, and would run leaner than the rest, but also realize that maybe cylinder 6 needs a little more fuel since it doesn't get the best cooling air flow being next to the oil cooler.
Anyone have correlated data on which cylinders seem to get the most detonation in these turbos?
Chris at Turbokraft mentioned he saw alot of damaged cylinder number 6 in general if I remember him right, but I was looking for more examples from other forum members to get a consensus or trend going.
Figure this might be good info for others looking at optimizing the FI on these cars.

[RarlyL8]

2&5

[jwasbury]

#6 was the majorly lunched cylinder/piston on my engine and I think on John's (aka citrus) engine as well.

[JBL930]

When mine went lean and melted a piston, it was number 5 that went.... Hadn't flow checked the injectors or checked for balance between all 6, so may be coincidence....

[smurfbus]

I asked if turbokraft had flow tested the stock IM but Chris said he'd asked for it to be tested but extrude hone did not do it.

I placed the most flowing injectors in order 5, 2, 6 but they were really close to each other.

[heliolps2]

I had the same problem , I removed one of my heat exchangers and noticed cyl 2 was very white , then I removed the other heat exchanger cyl 5 the same .

I tested the fuel system , I removed the fuel line from the injectors at WOT and got perfect results. OK I thought , may dirty or bad injectors , so I tested the injectors at idle and at 10% an 25 % throttle then WOT and again got perfect results.

I talked to Chris at TurboKraft he suggested that I adjust the fuel head on cly 2 and 5 !

I have the blk FD thats been modified to 320 ml per min with the 009 injectors , I thought they were maxed out , But I went for removed the little caps next to the fuel line and turned it clock wise one full turn and started the motor, it did with alot of smoke.

Too much turn it back half a turn the smoke stooped , I drove the car that way for a few days until I got my inferred temp gun , too rich turned back a quarter turn EGT seam OK .

I drove for a couple of weeks and pulled the heat exchanger and perfect color , I had to adjust my CO every time I made a adjustment. No more bouncing AFR's .

[911st]

FYIW, I suspect any cylinder can to go lean.

However 2 & 5 tend to run hotter and detonate sooner.

[pkracer21j]

I'm in love with that last pic!!!!

[fredmeister]

[QUOTE=heliolps2;6054019]I had the same problem , I removed one of my heat exchangers and noticed cyl 2 was very white , then I removed the other heat exchanger cyl 5 the same .

I tested the fuel system , I removed the fuel line from the injectors at WOT and got perfect results. OK I thought , may dirty or bad injectors , so I tested the injectors at idle and at 10% an 25 % throttle then WOT and again got perfect results.

I talked to Chris at TurboKraft he suggested that I adjust the fuel head on cly 2 and 5 !

I have the blk FD thats been modified to 320 ml per min with the 009 injectors , I thought they were maxed out , But I went for removed the little caps next to the fuel line and turned it clock wise one full turn and started the motor, it did with alot of smoke.

Too much turn it back half a turn the smoke stooped , I drove the car that way for a few days until I got my inferred temp gun , too rich turned back a quarter turn EGT seam OK .

I drove for a couple of weeks and pulled the heat exchanger and perfect color , I had to adjust my CO every time I made a adjustment. No more bouncing AFR's . ========

Helios, wow thanks for the detailed info. thats what i was trying to see. I love that last picture.....can anyone say throttle steer?

Also thanks everyone else for their info.

I plan on installing Cyl 2,5 and then 6 as well in that order.
Just for giggles, when I damaged my piston it was number 6 that went down. But cylinder 5 was low on compression too.
Surprisingly my original rings were not in a million pieces in fact they were still intact in most of the cylinders but number 6.

[Thierry25]

[QUOTE=fredmeister;6055420]

Originally Posted by heliolps2

I have the blk FD thats been modified to 320 ml per min with the 009 injectors , I thought they were maxed out , But I went for removed the little caps next to the fuel line and turned it clock wise one full turn and started the motor, it did with alot of smoke.

so far , one full turn on these screws is completely out of the required precision range !

While I did my injectors flow matching, I dealed with something like 5 to 10° max on the wrench rotation in order to get 2% flow balance !!!!

[Thierry25]

Originally Posted by fredmeister

I tested the fuel system , I removed the fuel line from the injectors at WOT and got perfect results.

Do you mean that you checked the fuel flow without the injectors ????

You must keep the injectors on their fuel line to do the flowing test !

[JBL930]

You should also have 14+volts going to the battery too, right?

[lucittm]

It was #5 for me. Broken rings...

[heliolps2]

I did a flow test both with out the injectors and with the injectors . in my case 20 degree turn did the trick.

I did the flow test with a battery charger plugged to it .

like I said , I pulled the heat exchanger off and the color where even on all cyls
and the spark plugs looked great.

And my AFRs was not bouncing around any more . I think I might saved this motor, this is my 3rd one since 1999 , the first two lasted 10,000 miles each ,

Each time it blow it was cyl 5. wonder way

[fredmeister]

To summarize so far, its looking like the trend is Cyl 5 then 2 then 6 in terms of failures or lean running/detonation.
This makes sense if looking at the flow of the stock manifold since it looks like cyl 2 and 5 would see the most air flow. Cylinder 6 I just think needs to contend with less cooling air flow since the fiberglass ducting to the oil cooler starves it for air flow from the fan.

Its good to confirm this theory with hard data though....thanks everyone.

Fredmeister

[RarlyL8]

Your original question asked which cylinders run leaner, which is 2 and 5.
If you want to know which cylinders fail more frequently that would be 3 and 6. The reason is as you sited, less air flow to those cylinders causing them to run less cool than the others.
These 2 issues become critical on hi-performance engines such as Helios monster. Not only do you need to balance the fuel head but you also need to set the timing based on detonation data gathered on cyl 3 and 6. Without these adjustments the life of the engine can be dramatically reduced, the time of which correlates to the level of performance enhancement, climate, and how the car is used.

[heliolps2]

Hey Brian

Would you say that timing would be more critical , lets say track vs street.
I have ROW 66 distributor with dual vac with the stock internals, which calls for 29 deg at 4000 rpms , that's where I run it on the street ,

On the track I would pull the timing back to 27 deg, I also run the Bosch W4CS plugs a little hotter , But then again ,I only do 1 or 2 DE a year and 6 auto cross events but mostly street driven and burst of boost here and there,

I is also believe that the gas that I been using in Texas and now Virgina is 93 octane , the same as Euro gas,has helped ALOT

When blow my first 2 motors I lived in California which has 91 octane , which did not help the issue , 2 cyls running lean to much timing , low octane and which lead to incorrect AFR reading .

It's all important

Brain thanks for you Help, my next project is installing a Andial Fuel control Dampener

Have you read the latest Theard, 965 3.6 intercooler Brumos Race and the link 930SE at the end of the theard ,Very cool thats where I got the Idea , Let me Know what you think