1999 TA A4, Stock L33 with LS6 springs and pushrods, Huron Speed AC retaining kit, Ebay Turbo now with the 12psi springs in the WG..

Tuning on 87 Octane. It's going very well except I see these KR hits on occasion, ONLY during rampup towards WOT. I never see any at any other point, and never see ANY KR at any point of WOT.

Is this something I should be worried about?

.I have to do slow rampup to WOT to prevent wheelspin while I'm tuning on the street. And no I'm not complaining.

 

Now that I'm looking at it, I guess that could be a downshift kickdown happening right at those points as I'm easing into WOT. That could be false knock from that shock...? I'll try to remember to log the selected gear next time.

Funny how all those lines crossed at exactly the same point of peak knock tho

 

Looks like it's happening during throttle opening, could be the burst knock settings ? As I understand it those are calculated and can be zeroed out (search that for your ecm ) I notice that there is a second KR spike just after that point on the log - makes me think real knock . Try taking out a degree from the spark table in that area and maybe in each surrounding box and retry . Also may need to get it a bit richer ( I know that's only ~ 2lbs of boost but 87 octane and a stock cam could be making very high cyl pressures at that rpm) by commanding richer or adding to the PE / BE Tables or bumping up the VE in that area and retry .

 

I would add the fuel first , see what happens. To keep things alive I'd be under 12:1 in any boost and 11.5 or better after a few more lbs -safe. Looks like it gets there on the log

 

Thank you. This is very helpful. If weather/work permits I'll do that in the next 2 days, trying to add the fuel first as you advise.

Any reason to not take it to the track Friday night while it's doing this if I don't get it figured out?

I know this non-WOT KR concern may seem petty to some, but this is all new to me and I'm not sure what might be important and what might not be important. I am finally in a good place with this car and want as little risk as possible. If I blow it up on my first run because of some little oversight I'm gonna open a vein. :-)

I thought I blew it up last night when I hit revlimiter at WOT because the extra power requires pulling back the shiftpoints. Sounded like gunshots, but louder. But that's an easy fix. :-)

 

Just relating what I've seen and done , there are others with way more knowledge in here. Seems like you're knock sensors and settings are keeping it safe , you could a.ways put in some 91 or 93 for the track -insurance. Don't forget that every time it pulls timing you are losing some power . I spent quite a bit of time eliminating all knock while keeping sensors quite active for safety on pump gas . Another thing that can help is getting the ECT down , if the cooling system is up to it ( rad , fans , settings) A cooler Stat is all it will take to get temps down and a little more knock resistance.

 

Not an expert tuner by any means but I wouldn't race it until you get all the knock sorted out.
Those hypereutectic pistons in a stock bottom end do not respond well to knock especially in a FI application.
Absolutely throw 91 or 93 in the tank and maybe even a bottle of octane booster for track days, better safe then sorry.
Just my $.02

 

FWIW I've read here that hitting the fuel cut limiter under boost is potentially very bad. To avoid this I maxed out the factory value and instead cut alot of timing and added a bit of fuel above my intended Rev limit- worked great when I broke my diff and again when I accidentally had my column shifter in 2nd at the track LOL

 

Bingo. I do the same thing. Add fuel, dump timing, and have a high rev limiter.

If you're going to run crap gas at least put a cheap water/meth kit on it and run windshield washer fluid.

 

Try running better gas as an experiment and see if it goes away with no other changes. 93 or even some 100 octane race gas.

 

All great advice.

So my plan is to do my best to get all that knock out of the car before track day as mentioned. And, I am going to backfill some of the safe settings (AFR/Timing) to cover all earlier areas where I am > 100kpa (boosted areas). If I can't get the knock out before track day, I will also throw in 93 octane, but would rather not do that unless I'm fearful of a kaboom.

The main purpose of the track day is to get the car tuned for DD duty. So I want it to mirror what the car will be seeing on the street. And that'll be 87 octane typically. And I'm going to do my best to not have meth, I'll just keep pulling out power through timing or AFR until 87 runs clean and we'll see where we land. It's still likely going to be quite strong.

My goals are to just have a fast fun inexpensive DD, and bonus points if I can outrun new stock Mustang GTs it seems all these kids are getting for graduation presents LOL. So I think 11.8's or better and I'm happy. It ran a 12.1 on the 7psi spring (surprise 80 degree day in Pittsburgh, logs showed boost on that run was only 135kpa). My logs are now showing 11psi with these WG springs, so I should be good.

And yes, hitting that rev limiter was very violent, not surprised it has big risk to do damage. I hit it once for ONE loud pop and let off, thought it was a backfire or something. Checked everything out and ran it again and it did 3 pops in a row but this time I saw it in the logs that it clearly wasn't able to meet the upshift MPH criteria. So yea I'll be bumping that WAY out so the redline doesn't happen again. It was so bad I thought the engine was gonzo LOL, it was especially loud because I'm tuning with straight downturn pipe to the ground with no muffler for now :-)

 

where do u find 93 octane at. Im in wichita/derby area. All i see is 30% ethanol blend added. Thnx

 

91 is predominantly found everywhere, I've found pump 93 a few times while traveling the country but its not a regular thing.
Same thing with E85, hard to find out west, offered all in the midwest.
Some places offer Trick 101 at the pump, there's a local gas station here close to the race track that has it.
Anything higher has to be bought by the pail or drum from what I've seen.

 

30% ethanol would be a lot better than 87!

 

Wasn't sure where the OP was from... I just meant "premium" i'm a FL boy so we always called it "93".

None in wichita I'm aware of. Only Ethanol blend stations. E50-E60 is the sweet spot IMO. enough octane for most, allows the fuel system to go farther than it would on E85, and allows a little better economy. I'm able to run 20lbs or so non intercooled on it anyway. Hydraulic and 96 has straight 91 with no ethanol though. Its a great fuel to "blend" if you are making your own. 21st and west sells E98.

 

Good gas is cheap.

Engines are expensive.

Even racing fuel is cheap as chips compared to new engines.

Plan accordingly.

 

Engines are pretty darn cheap assuming you are under 1200whp or so, can still find 5.3L's under $600. No way in hell I'm going to put fancy fuel in an old truck engine.

 

Time is money and you only live so long.

For math sake, lets say that running good gas will save you one engine. And lets just assume that when it blows up, only the junkyard parts are destroyed. $600 plus the inconvenience of having rendered your car dead wherever it blew up, needing to find, haggle, pull, inspect, and possibly find that the $600 engine is hashed and has destroyed bearings (I have personal experience with this). If the engine is good, tear it down, ring gap, gaskets, work on every little bit, not do any driving of your car at this time. Install, tune, and all this just to get back to where you were.

A few gallons of race fuel is a lot of insurance for a l few dollars. $600 will buy a 55g BARREL of pump Sunoco 110, and if thats too rich it will buy tanks of E85.

 

I have AAA that takes the car right back to my garage, engine is out in an hour, I have a spare 5.3L sitting in the corner of my garage, I do all my own tuning, so the car is down for a weekend every couple years when they finally give up, that's really not a big deal. I don't bother with gapping rings, no issue with SBE high mileage truck motors over 30PSI on E85. My point is I'm not paying for fancy fuel that costs more than pump E85 which is usually $3 or less a gallon, $11 gal fuel is for suckers.

 

Hey now. Those 5.3s used to be 300, that's a 100% increase! 🤣🤣🤣