12 Degrees Knock Retard @ 13# Boost...WTF?

[zhorner]

Freshly rebuilt motor and trans, nearing the end of my 1,000 mile cam break in period (flat tappet). Gave it some gas on the highway today and KR went through the roof. Just filled up on 91 octane gas and have the alcohol turned off for now. I have a TT Alky chip...which I understand is burned with the assumption that my kit will be pumping methanol under boost...but it seems to me that with 60# injectors I shouldn't be seeing any KR at such a low level of boost. Heck i was already at 2* knock under 10# boost. On a side note, I was at 50 PSI fuel pressure when this went down.

This car has been fighting me for over 3 years of rebuilding the motor and trans and I am so close to being able to enjoy it...please help.

 

[Steve V]

Fuel PSI should be at least 55psi so start there.

 

[zhorner]

alrighty. I set it at 43 line off, I wonder if the fuel filter needs replaced...ill double check it,

thank you for the reply

 

[m233roller]

Just remember fuel pressure plus boost number and you better see that. Like 43 lbs. fuel pressure and 13 psi of boost. You better see 56 lbs. of fuel pressure.

 

[zhorner]

I know that...probably read it a dozen times. im just such a worm it didnt even register. Thanks for pointing out what should have been obvious guys ill tinker with it and report back.

 

[theCATman]

Alcohol chip also has a fair amount more timing advance than pure gas alone will tolerate, especially compounded with boost.

My guess is if you turn the timing down to 18° 1-2 & 16° 3-4 gears your knock will go away.

On the other hand, why did you turn alcohol off? If you turned the boost down, all that will happen is a rich condition.

 

[zhorner]

Alcohol chip also has a fair amount more timing advance than pure gas alone will tolerate, especially compounded with boost.

My guess is if you turn the timing down to 18° 1-2 & 16° 3-4 gears your knock will go away.

On the other hand, why did you turn alcohol off? If you turned the boost down, all that will happen is a rich condition.

I turned it off during the break in period since im not getting on it. This was the first time ive given it boost since the initial start up to set the rings. Just really felt like with 60# injectors I would be covered to 13 lbs boost even with a higher level of timing. This has all been an uphill learning process and I really appreciate everyone's time and advice. I got the alky kit filled and primed last night so I might as well turn it on aye.

 

[theCATman]

The size injector has nothing to do with the ability to supply enough fuel to suppress knock if the fuel itself isn't up to the task.

Just use the alcohol...

 

[zhorner]

gotcha man...and love "is that a monte carlo"

 

[TurboDave]

Freshly rebuilt motor and trans, nearing the end of my 1,000 mile cam break in period (flat tappet). Gave it some gas on the highway today and KR went through the roof. Just filled up on 91 octane gas and have the alcohol turned off for now. I have a TT Alky chip...which I understand is burned with the assumption that my kit will be pumping methanol under boost...but it seems to me that with 60# injectors I shouldn't be seeing any KR at such a low level of boost. Heck i was already at 2* knock under 10# boost. On a side note, I was at 50 PSI fuel pressure when this went down.

This car has been fighting me for over 3 years of rebuilding the motor and trans and I am so close to being able to enjoy it...please help.

What in the world caused it to go so lean there just before your cursor position. 12.6 AFR as the boost comes up to 13. the AFR should have stayed down there in the 11.5 range seen before it suddenly went lean. Solve that lean problem you'll likely solve your kr issue.

 

[REAPER231]

You need to also tell us what plugs your running to0 and what pump or pumps you have out back I'm on my phone so I can't see if you have a writeup in sig

 

[zhorner]

dw300 pump, NGK "R" UR5 plugs

 

[Pronto]

Do you log your fuel pressure? That would certainly be interesting to see...

 

[REAPER231]

dw300 pump, NGK "R" UR5 plugs

I'd go 1 step colder to ur6 plug . ur5 is stock heat range. been running my car like that for yrs on 93 pump at 22 lbs and 18 degrees of timing . And on c16 at 21/22 degrees with 28/30lbs of boost with my iron heads . What is chip setup for with timing and what boost levels .

 

[zhorner]

 

[REAPER231]

I'd go 1 step colder to ur6 plug . ur5 is stock heat range. been running my car like that for yrs on 93 pump at 22 lbs and 18 degrees of timing . And on c16 at 21/22 degrees with 28/30lbs of boost with my iron heads . What is chip setup for with timing and what boost levels ? I keep my gap a tight 0.28 gap , never get spark blowout .

 

[Pronto]

Do you have the wb tracking activated? What are you running for a fuel pressure regulator?

 

[zhorner]

23* / 21* timing - 25# boost

 

[Pronto]

Something in the fuel system is not letting the pressure track 1/1. Shouldn't go lean like that.

 

[zhorner]

Do you have the wb tracking activated? What are you running for a fuel pressure regulator?

yes