Cat Zuk big bore low elevation

[Thunder101]

Anyone have troubles tuning a bigbore at low elevation ? I have had many mod engines and they all took a bit to dial in but this last one is just a pain, even at 9.5:1 -10.25:1 it is setting off octane code right before valve opening.
no data logging just a NGK a/f gauge next to my tach.
In the past I would add 25% av and not be so stubborn but this is not my main sled and I want to get it figured and run pump.
I started w a 2.5 key and stock pipe w DD can then tried stock can then I removed the stock exhaust and timing key . Tried a FatAzz pipe w the DD can. With any combo I can drive through it and get a ok tune but the second I have to cruise in that 6800 rpm range the octane code comes on.
it’s a 2011 Crossfire w a 920 Dakota 50 mm tb, 1000V force to fit the tb.
Im going to call Jaws and possibly get them to make me a pipe , I’m kind of scrambling. Would sure like to have about 4* removed from 6800 range. Oh which reminds me I had a 2010 ECU in it at first the switched out to a 2011 (yes I switched inj w it) because the 10 was know for hot mid.
maybe a vipec is what I need hahaha.
any ways if anyone has any ideas I’m all ears.
I have even thought about cutting open a pipe to shorten the internal stinger but
i think buying a pipe would be smarter.
help

 

[hpjunkie]

I think you would get more help on an Eastern based site where these combo's are plentiful & knowledge abounds! Good luck!

 

[SUMMIT TREE]

There is something about that Rpm they don’t like. My buddy has a 925 and its the same thing. If you try cruising in and around that rpm its very burbly and gargly. If you punch it through that rpm no problem. Below also no problem. Not sure what it is or if it can easily be fixed.

 

[Beels]

Anyone have troubles tuning a bigbore at low elevation ? I have had many mod engines and they all took a bit to dial in but this last one is just a pain, even at 9.5:1 -10.25:1 it is setting off octane code right before valve opening.
no data logging just a NGK a/f gauge next to my tach.
In the past I would add 25% av and not be so stubborn but this is not my main sled and I want to get it figured and run pump.
I started w a 2.5 key and stock pipe w DD can then tried stock can then I removed the stock exhaust and timing key . Tried a FatAzz pipe w the DD can. With any combo I can drive through it and get a ok tune but the second I have to cruise in that 6800 rpm range the octane code comes on.
it’s a 2011 Crossfire w a 920 Dakota 50 mm tb, 1000V force to fit the tb.
Im going to call Jaws and possibly get them to make me a pipe , I’m kind of scrambling. Would sure like to have about 4* removed from 6800 range. Oh which reminds me I had a 2010 ECU in it at first the switched out to a 2011 (yes I switched inj w it) because the 10 was know for hot mid.
maybe a vipec is what I need hahaha.
any ways if anyone has any ideas I’m all ears.
I have even thought about cutting open a pipe to shorten the internal stinger but
i think buying a pipe would be smarter.
help 

Have you talked to Jeff at Dakota Performance?

 

[Thunder101]

Yes I have quite a few times. Jeff is great and has given me some good options, like a different heat or even trying double base gasket. I have a DD lts head on a 800zuk and it works well.
�� going to make a few more calls