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I just spent a couple weeks putting ~2500 miles on my car while burning 10 tanks of Premium grade gasoline purchased all around central, north, and south-central Texas. While doing that, I managed to do some good sciences. This post will try to convey some of the data I gathered and conclusions I drew based upon that data.

Setup/prerequisites:

- I ran a bottle of OTC** octane boost in each tank and data logged as much of the driving for that tank as I could.

- The vast majority of the miles were highway miles, and many were driven at night. Average ambient temps were in the 50F-60F range, with several extended periods of near freezing temps encountered.

- I was using s slightly modified (and continually changing) version of the 93 octane tune from DiabloSport’s T1000 handheld tuner.

- All tanks of gas were ethanol blends of the gas stations’ premium grade gas, which turned out to be E10 in every case.

- The gasoline was Top-Tier 93 octane in 9 of the 10 tanks.

- One of the tanks was non-Top-Tier 91 octane E10 purchased by accident (the pump button didn’t have an octane rating sticker, and I assumed their premium was 93 octane but it was 91 actually).

In the interest of readability, I am going to split this into several posts. This concludes the first of these posts.

To be continued...


** - OTC just means commonly available brands that can be purchased locally without having to order and wait for delivery. The octane boosters I used included the following: STP brand w/MMT (1 number boost), QuikTrip brand w/MMT (1 number boost), Lucas brand w/MMT (3 number boost), Turbo 108 w/MMT (2 number boost).

(The number boost value just means how many extra octane numbers can I add to the gasoline’s advertised octane to get my final realized octane level.)
 

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Discussion Starter #2 (Edited)
After reviewing the data logs and making changes to the tune, I would keep doing that (datalogging, test driving, modifying the tune is necessary) until all the LTKR and STKR were gone, or as much as possible anyway.

All said and done, I have drawn a few conclusions based upon my data and the experience in general, and I will list those here. Feel free to question me on them if you want, just know I’ve never been wrong about anything...ever...nope, not even once!

1) It is clear that the 93 octane gasoline commonly available in this half of the state is not actually (effectively? realistically?) 93 octane. At least as far as my particular engine (5.7L w/170K miles) and the DiabloSport 93 octane tune are concerned.

NOTE: I checked my combustion chambers for signs of excessive carbon buildup which might cause higher compression and more knock as a result, but the tops of all the pistons were virtually spotless (no doubt thanks to my prodigious use of TT gas and PEA additives when TT is not available).

2) It is clear that the octane boosters with MMT can raise the gasoline’s effective octane level to make up for poor/inadequate premium grade gas from some stations. Further, how much of a boost each product provides can be extrapolated from its price point for the most part.

The $3-5 bottles (STP and QT) will add about 1 octane number. The $6-8 products (Turbo 108) will provide a cushion of about 2 octane numbers. The $9+ products (Lucas, RP, etc.) will boost octane about 3 numbers over what’s advertised on the pump.

3) It is equally as clear that continued, regular use of the OTC octane boosters is not a viable way of meeting the 93 octane requirement of the DS canned tune.

The spark plugs in my engine were covered with manganese by the end of my experiment. They weren’t covered to the point of fouling, but they couldn’t have been too far from it. (Manganese is one of the Ms in MMT IIRC).

4) My best option for running the hottest tune possible while avoiding the need to constantly treat my fuel with octane boosters is to either retard the WOT timing of the 93 tune or advance the WOT timing of the 91 tune so that I am no longer requiring 93 octane gasoline for KR-free WOT operation...something like 92 should be just right.
 

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I have finally decided on which way I want to go with my tune. I decided to go with the canned 91 tune from my Trinity tuner and modifying the WOT spark parameters to add 1 degree of timing across the board at WOT.

I chose that approach over the alternate (93 canned tune with 1 degree subtracted at WOT) because of the other difference between the 91 and 93 canned tunes on my tuner - torque management.

As I understand it, the PCM applies torque management at WOT shifts to mitigate the effects of the violent torque shifting can bring to various drivetrain components, and it does this by altering the amount of fuel sprayed for combustion (reducing it briefly). The 91 canned tune has reduced torque management, while the 93 canned tune has almost no torque management.

This bears itself out in my WOT data logs too, as I see some pretty significant KR spikes at shift points when running the 93 tune versus the 91 one. That is the reason I went with the 91 as my base tune from which to add my modifications, I want as little KR at those shift points as possible.

I will still have to purchase 93 octane all the time now, but I can stop having to use octane booster with every tank like I was with the unmodified 93 tune.

Anyway, that’s my story and I’m sticking to it!

Nuke, OUT!
 

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This is excellent stuff! #following #riveted
 

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This is excellent stuff! #following #riveted
I’m glad you replied to this thread, I had gotten sidetracked with a different thread yesterday and totally forgot I had not finished this one yet😔

Anyway, I have attached some more pics relevant to all this, and I still need to populate that 2nd post of mine with some more info (not to mention add some context to the pics so they will make sense), but all of that will have to wait until later.

At the moment I am trying to splice 8 wires into 4 different wiring harness bundles behind my dash in anticipation of a speedy hook-up of one of my Xmas presents later. And I have to get that pre-wiring finished and tested before we leave town in 2.25 hrs. 😯

I could tell you I’m almost done and it won’t come down to the wire (pun intended), but I think we all know that ain’t the case with me...ever🤥

983486
 

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That looks...challenging! Good luck to you sir in your race to make it across the "wire" in 2.5 hours. (weak pun most definitely intended)
 

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Wow you are a busy guy. I feel your pain. I have to rewrite my 2 Step. Just been putting it off.


Sent from my iPhone using Tapatalk
 

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FINISHED!! (with the pre-wiring part...now I just hope it all works later today when I get my Gen II TranZformer from Santa Claus)

983494


And the best part is we are only 30 minutes behind schedule leaving town. That’s small enough that I think I can put the hammer down to make up for it.:cool:

I seem to always run across reasons to “put the hammer down” it would appear...almost as if I’m always late on purp...n/m, gotta go!!
 

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So I just replaced the upper radiator hose on The Bacon Hauler and took the opportunity to do some datalogging while on my test drive for the radiator hose work, and I have (hopefully) finally arrived at a practical yet affordable approach to my octane vs tune vs KR issues.

I still run the 91 canned tune modified to add 1 degree of timing across the board at WOT, and I have some good datalogs to show that a mixture of 93 octane e10 gasoline and 92 octane e0 gasoline gives me the fuel my tune needs without any extraneous KR.

The e10 93 octane all by itself still had some KR in the 4-5K RPM range with my tune, and I have to run some octane boost to get rid of it. That’s not only expensive but not very practical because I’ll be cleaning my spark plugs too often.

But I have discovered one of the Bucee’s truck stops here (the one in Denton) offers ethanol-free gasoline at 4 of their pumps and its 92 octane, or basically exactly what I need for my tune.

I would run the e0 92 by itself but that’s too expensive for me. It is >$0.50 more per gallon than the e10 93 gas, so that adds up quick on a fill-up...too quick.

But cutting it with some e10 93 (about 1:1) seems to do the trick right nicely.

Anyway, I’m gonna keep using this recipe for the foreseeable future and see if this trend of little to no KR at WOT holds.

Nuke,OUT!
 

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I am doing some experimentation with different spark plug types, and while I’m only running each kind for 1-2K miles, the effects of using the OTC octane boosters is quite evident.

(I think I previously said the reddish-brown deposits left behind from their use is magnesium. If so, I misspoke. It is manganese, not magnesium.)

The following pics are of a set of Champion Copper Core plugs which were installed brand new about 2K miles ago. I used quite a bit of the MMT-laden octane boost during those miles, which is evident by the reddish-brown deposits left behind:


259259F7-E637-4D43-A825-0B1BF4659009.jpeg


91C1667E-ECAB-4F25-82AE-60C4BE0AB7ED.jpeg

4C85AAAC-C623-4FFD-B7B2-DEBBFE2ECE1E.jpeg

As disconcerting as those images might be, I cannot tie the deposits to any undesirable effects just yet.

And now I will be happy to take some questions...

——————
Q: Do the deposits hurt performance or MPGs?

A: Not that I can tell. Performance and MPGs remain the same after installing new, deposit-free spark plugs.

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Q: Can the deposits be removed without affecting the plugs’ subsequent operation?

A: Yes, I have cleaned them successfully without hurting their performance by removing them and manually cleaning them with a brush and some brake cleaner (chlorinated).

I have an idea that I could leave them in the engine and chemically clean them over time by using products like Techron and Regane with my gasoline fill ups (or exclusively running Top-Tier branded gas), but have not had enough time to test this theory yet.

—————
Q: Does the plug type have any effect on how quickly these deposits build up?

A: Not that I can tell.

I have tried 2 different brands of Copper Core, one brand of Double Platinums twice (same set once and then again after cleaning), and one brand of Iridiums so far. All accumulate the deposits at the same rate, and that rate is directionally proportional to the MMT content of the octane boost being added to the gasoline.

——————
Q: Aren’t you concerned about the long term effects burning all this octane boost could have on your cats?

A: No, I make sure to keep all my automotive chemicals away from our household pets.

——————
Q: Why are you such a dullard?!? I was asking about the possible effects on your car’s catalytic converters!

A: Ah, okay...Well, the possibility that I am reducing the lifespan of my car’s catalytic converters has occurred to me, but I just put it out of my mind anytime it comes up.
—————

No more questions!!

Allow me to say one last thing in regards to what’s going on here:

Nothing, and I do mean nothing, will stand in the way of me doing my sciences!! That is my pledge to you, fellow gear-heads.

Nuke, OUT!
 

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It would be worth finding out what all of this is doing to your catalytic converters, because if they blow, you'll not only have to replace them, but the mufflers behind them as well because they'll get clogged up from the converters. As for plugs, I'd only run NGK iridiums, and that's what the stock Mopar plugs for my Shaker are. And then, I do use NGK iridiums, just not stock. There ain't no 93 octane gas in my neck of the woods, so I wouldn't know about that. I have thought about mixing avgas with my 91 octane to boost it, but haven't tried it yet.
 

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It would be worth finding out what all of this is doing to your catalytic converters, because if they blow, you'll not only have to replace them, but the mufflers behind them as well because they'll get clogged up from the converters. As for plugs, I'd only run NGK iridiums, and that's what the stock Mopar plugs for my Shaker are. And then, I do use NGK iridiums, just not stock. There ain't no 93 octane gas in my neck of the woods, so I wouldn't know about that. I have thought about mixing avgas with my 91 octane to boost it, but haven't tried it yet.
The NGK Iridiums are good plugs, I’ve run them before. But I’m not looking to drop that much coin on a set of spark plugs right now when I won’t be running them for the 100K+ miles they can supposedly last.

After I run these Autolite Iridiums for a while I’ll probably grab a set of the NGK Ruthenium plugs though. I figure they may not be worth the extra $5/plug when it comes to performance, but that’s a small price to pay for bragging rights the next time I’m holding court in the drunk tank.
 

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"Yeah, well, my spark plugs are named after an Associate Justice of the U.S. Supreme Court"

A Guy
 

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"Yeah, well, my spark plugs are named after an Associate Justice of the U.S. Supreme Court"

A Guy
Wild guess: you haven’t been in many drunk tanks, have you... 🤓
 

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It would be worth finding out what all of this is doing to your catalytic converters, because if they blow, you'll not only have to replace them, but the mufflers behind them as well because they'll get clogged up from the converters. As for plugs, I'd only run NGK iridiums, and that's what the stock Mopar plugs for my Shaker are. And then, I do use NGK iridiums, just not stock. There ain't no 93 octane gas in my neck of the woods, so I wouldn't know about that. I have thought about mixing avgas with my 91 octane to boost it, but haven't tried it yet.
That’s weird, I wouldn’t have figured you for a tree hugger, but hey, to each his own I always say!
 

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That’s weird, I wouldn’t have figured you for a tree hugger, but hey, to each his own I always say!
Wild guess; you've been in too many drunk tanks, haven't you...
 

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Don't use fuels / additives with MMT; FCA calls this out in the owner's manual

its know for reducing spark plug life (mentioned in manual as well)
 
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