B1 and B2 Inj msec different?

[2005vetteTT]

Hey all -

I noticed recently that my Inj B1 and Inj B2 msec at WOT are different. In the attached log (logknock) you can see where I get KR is in Cylinder 2 and B2 goes to 12.1 VS B1 at 12.6.

The car is a twin SC61 setup on an LS2 vette. 317 heads, PRC .655 Valve springs, 228/222 .58x .58x 114.5 cam. 80 lbs inj with BAP. AFR was rich at 11:1

What I don't understand is my dyno log is the opposite. The car used to goto 60+% duty cycle with a leaner mixture and now is only going to 55~.

The car did not use to have this variance.

Attachment 31436

Attachment 31437

[gn2beatu]

Did you do a cylinder balance test? I like to do that and have my injectors flowed. Then match injector to cylinder based on flow rate(s). That will help some. But at 11:1 you are probably getting rich knock. I would verify that 11:1 by double checking with someone that has a known good wideband BEFORE you do much more tuning. You dont want to lean it out, only to find out later that it wasnt that rich and end up damaging something.

[IDRIVEAG8GT]

Do you have cats?

Sometimes my cars vary from .2-.4 on certain days. No problem that I can really see for that.

I'm slightly concerned about having a split duration cam like that with boost, but my knowledge of your 317 heads flow characteristics is virtually zero.

Sounds like someone messed with the data for the injectors, or your "scaled" tune wasn't scaled properly.

[2005vetteTT]

I was always told turbos like reverse split cams. I could be wrong but the LT1 guys loved em.

[DSteck]

Reverse split isn't uncommon on turbo builds, although Pat G didn't spec that for me.



OP, were your LTFTs zero before entering PE? I see bank to bank variance when a big LTFT gets carried over.

[2005vetteTT]

I did a cylinder balance test and they were all at 100-102. My wideband was really close to my dyno run's AFR so I assume its right

[IDRIVEAG8GT]

Reverse split isn't uncommon on turbo builds, although Pat G didn't spec that for me.



OP, were your LTFTs zero before entering PE? I see bank to bank variance when a big LTFT gets carried over.

Hmm, I shall return to Google. Pat didn't spec a cam like that because your heads have some big ol intake valves in comparison to your exhausts, therefore he wanted to keep your flow characteristics balanced out for to make power efficiently. 317 heads have much smaller intake valves, and cathedral intake ports. The cam selection for style of heads versus application is totally different.

Anyways good points upon LTFT's.

[DSteck]

Even now, people spec out reverse split cams on LS7 heads. I don't know how to spec a cam, so I can't say the reasoning behind one or the other.

[edcmat-l1]

Even now, people spec out reverse split cams on LS7 heads. I don't know how to spec a cam, so I can't say the reasoning behind one or the other.

I've never seen a reverse split for an LS7 headed N/A motor. That would just be stupid.

Reverse split cams for turbo motors are usually based on pressure ratio.

[DSteck]

I've never seen a reverse split for an LS7 headed N/A motor. That would just be stupid.

Reverse split cams for turbo motors are usually based on pressure ratio.

I'm speaking in terms of turbo cams.

[IDRIVEAG8GT]

Oh well, it has something to do with bleeding off boost.

[2005vetteTT]

turns out cylinder #1's spark plug wire wasn't not connected to the plug. once I put found that, both banks read the same!