I just had my k24/k20 dyno tuned on E85 this weekend and experienced some ignition breakup at 26psi. My car was previously tuned on 93 and make 521whp and 345wtq at 20psi on a dynojet. I went to a different tuner this time due to him being local and having hondata experience.
Here is my setup:
-k24 block with 10.2 wiseco pistons and Manley rods
-K20a2 head with BC valvetrain skunk2 IM
-cxracing gt35r turbo kit with tial wastegate and greddy bov
-kpro v3
- walbro 450lph pump
-FID 2000cc injectors

So I never had any ignition issues prior on the 93 tune but I did change the fuel setup from dw 1300cc injectors and 300c pump to what is in my list above.
So, I flash the e85 basemap that he sends me to drive the car to the shop and I notice I have a slight misfire under partial throttle, weird. No big deal, I get to the shop, Change my plugs when I get there with a fresh set of BKR7Es gapped to .018 and I can still hear a slight misfire. Get on the dyno and start setting up cruise and idle and can hear the misfire. Tuner says maybe it's due to the large injectors. We start setting up boost by gear. Makes 340whp on 11psi no problem. We start increasing the boost and it starts to misfire/breakup. He tells me it's more than likely coils/ignition system. We order some parts store coils, install them and the issue goes away, problem solved right?

So we continue to increase the boost pressure and everything is going along nicely until we get to 26psi. Has one slight hiccup/breakup but we continue the pull and it makes 540whp and 402wtq. This is on E85 and a mustang dyno. He says it looked a little rich so he pulls fuel and does another pull. Breaks up bad this time. His wideband is pooping out now and starting to read really rich so he starts to have to use mine which is not connected to my ecu so he's just watching it. Maybe that's why when he pulled fuel it broke up even worse? Was it falsely reading too much when it was in fact leaner than it needed to be?

At this point it's late so we stop there and put the boost pressure back to 23psi as that was the last clean dyno pull that we had. He tells me to try a step colder plug and OEM coils and if I still have issues we can revisit the dyno and try to figure it.

Next day I install the bkr8eix plugs gapped to .020 and do some 4th gear pulls this morning and it seemed ok the first couple of pulls but it was hard to tell as the car spins through 4th. I keep driving it and start at around 3k rpm in 4th and can feel the breakup at higher rpms and my wideband shows a lean condition of 13.6ish to 1 af ratio. Is it possible that I am having Heat soak issues or am I just running lean from where we pulled fuel? Do ignition breakups show as rich or lean?


Next step is oem denso coils and try again.
I need to get datalogs of the 4th gear pulls to see what's going on. IAT temps should show heat soak but the tuner never mentioned issues with heat soak.

Any help/ideas would be great. Thanks in advance!
If I need to provide anymore info let me know.

 

With out being there it’s hard to know what’s really going on, but I would look into swapping to iridium plugs. I swapped to iridium plugs after 20psi and ran a gap of 23 until 26psi then I lowered the gap down to 18 when I had a little misfire (which corrected things). I’m running a b series but I’m sure most of the same rules apply

 

Thanks man, that's what I did. I went to heat range 8 (bkr8eix) ngk iridium plugs gapped at .020. I'll try bringing the gap down to .018. I'm also going to shoot for 26psi in third because it's hard finding a road for 4th gear pulls!

 

I can also share my tune with anyone who is willing to look over it and provide feedback!

 

The spark plug from cylinder 2 has white specks on it? Sign of a lean condition?

 

star dust effect is a sign detonation or way lean or timing to far advanced. You might want to take those injectors and have them flow tested

 

unfortunately I don’t know much about K stuff

 

^^ This.. Looks like cyl 2 is your misfire, by the look of your plugs.

 

well, now my 2nd gear decided to take a dump so I'll have to get that taken care of before I can continue diagnosing the ignition issue.

 

Definitely. I overlooked this last time. I had a turbo bolt back off so I wasn't able to recreate the issue last night as I never hit 26psi. But as I mentioned above, now I have a transmission to repair!

 

Go 1st to 3rd, yo!!

 

Is it possible for the injector to still flow ok and have this effect in the cylinder caused by weak ignition/spark?

 

hahaha I would but I hear something clunking around so I don't want to further damage anything!

 

doubtfully, you need good fire to get into detonation. I would do a flow test, make sure you mark each injector you remove

 

That sucks. These are brand new with flow results!

 

watch my buddy flow his new FIC’s and all they was all jacked up. Reading your plugs is the key to a good tune and that one plug looks fuel starved

 

This actually makes sense thinking back on it. When I first installed the injectors and the E85 basemap I was getting a slight misfire at partial throttle. Never had this issue before the injectors and E85 basemap. I chalked it up as something to do with the fuel change/basemap but maybe it is a weak or bad injector!

 

Definitely leaning towards a bad injector now due to the misfire I was getting at cruise speeds after I switched to these injectors. I have contacted FID to see what the process is to have them flow tested through them or whatever else I would need to do.

 

you properly have a local shop that has a flow bench. They are more common than you think

 

So I shouldn't send them back to FID to have them tested? They're still under warranty so I figured it had to be done through them. I was surprised with how fast they emailed me back.

 

If they are warranted, do that instead. Sending them elsewhere will only cost you more $$$.

 

Sounds good, that's what I'll do!

 

these are wrong plugs. They are not good for k20 coils. Run iridium plugs on oem honda denso coils. Never had problems by bkr8eix at 30psi gtx3582r gen2. 0.55mm gap.

 

That's what I switched to. I couldn't recreate the breakup issue on the road so I'll have to get back on the dyno after I fix my transmission.