No Fing power, that's who...

my car pulls a lot of timing due to really high knock values. There is no real pattern from cylinder to cylinder from run to run. I routinely see -8.5 thru -13 across multiple sensors.

Does anyone else see this? Mitch and Jon have been fantastic viewing my logs with me however they are very busy this week, plus I'd like to see what others have seen.

I'm not too sure it's fuel as I get my fuel at 3 different shell stations and I've ran 102 octane in the car and it still made a crap load of knock.

 

I know this may sound like a conspiracy theory, but are you sure you were truly running Premium fuel or true 102 Octane? Fuel do lose their octane over time. For Race Fuel, once the container is opened, the Nitrogen that was used to maintain the octane dissipates and the 102 fuel will gradually lose its octane rating over time. Others will probably laugh at this, but I ask the question since I have witnessed 92 octane gas that was actually 89.

 

I had some of that show up and Dzenno from PTF cleaned it up for me. Maybe try emailing him your logs for an opinion. He's a super nice guy and I'm sure he'd help. He's on here too so maybe he maybe he chimes in as well.

 

you realize those shell stations all probably got that gas from the same place right?

 

It's been the same for a few months. I will however try something different

 

Hi Ron,


Do you have logs to share? Also, what tune and mods have been performed? With -13, could be a few things causing this, exhaust restriction, intercooler, aggressive timing etc..

 

I'm in the same boat.
Although we only have 91 here. I'm running a pretty aggressive meth injection setup.

Dzenno has been great in initial troubleshooting.

I'm suffering from some 'tip in' knock as well as full throttle 5th & 6th shutter/hesitation. Even with the Cobb ACN91 tune.
If I slowly accelerate in 6th no knock is registered either. It's only when going 'full throttle'

I'm eager to see what you find as your solution.
I see no knock at 1-3rd gear pulls. So it's hard for me to think that it's actual knock I'm seeing.

 

Mine used to do it BAD. Mitch fixed it, when I run MS100 theres zero knock. I do still get -2.0 up too -5.0 on 93 from time to time.

 

+1 to Dzenno... SOLID guy!!!
I personally only use Chevron (94 octane in Canada) and have never had an issue with fuel grade. I have had issues with other brands.

 

OP feel free to shoot over some logs and I can take a look if you like. We've done it on a couple cars we've worked on so far. Tip in and as you cross 6k RPM are fairly common to see some timing pull happen. Your map may need some work but it also may not be the tune itself. It may also be related to an FPR line being off which maxes fuel trims which in turn upsets fueling which in turn causes knock. It can be your MAF sensor going out not reporting appropriate readings. If you've changed your intake pipes you may need a bit of work in the VE tables to get the fueling back in line and/or some changes to your timing tables. We've also seen some changes to variocam (intake valve timing) help in certain cases. Drop me a line with your log if you like and I can offer some advice if I can spot anything dzenno@protuningfreaks.com

Dzenno

 

I do have some on my google drive I'll get some up tonight.

I'm running tubi race exhaust and stock intercoolers. I ordered a set of AMS intercoolers from By Design and they will be here tomorrow. I've ran several maps but I've been running the stage 2 93 Oct OTS Cobb map lately.

 

Thanks for the info.

I plan on logging:

100 oct with the 93 oct stage 2 map see if the knock is still there.

Then log with a 93 oct stage 1 map see what that looks like.

I'd like to rule out fuel issues and MAF issues prior to installing the IC.

Once the only viable option is lower charge temps I'll install the IC and see what that looks like.

I've got some good logs in conjunction with pbox times so I should have some conclusive data on the AMS intercoolers.

Thank you Sam, Mitch, Jon, and the rest of you for being a great sounding board

 

Without even looking at anything I'll tell you I think that's going to do it. Then will smooth it out. Also just go MAFless with those plugs we were talking about. I'm going to hold you to it!

 

If you would have sent me those fittings you would have already be installing them.

I'll get some dims from mine

 

My machining days are over buddy. I'm passing the load on you haha
Remember this super hot summer is not helping anything.