Diablo Tune with 87 Octane?

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KDIXER
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Diablo Tune with 87 Octane?

Post by KDIXER »

I would like some input on this subject.

I have ran both the 87 tune and the 87 tune with 1.5° more WOT timing. I was not real impressed with the feel of the tune.

But I decided to try the Diablo Tune after not having much luck selling the tuner. I have a full tank of 87 octane but I have logged and am only getting the spotty TKR during throttle stabs and shifting like usual with any tune. But I can definatley tell an improvement in the way this truck pulls finally.

It is a 5.3L 6 speed Silverado aluminum block if that matters.

Let me hear some comments.
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06MonteSS
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RE: Diablo Tune with 87 Octane?

Post by 06MonteSS »

if you're using the diablo performance tune, use 91 or 93 octane gas, and the performance will be better...

I would definitely take it easy on WOT, since you only have 87 octane in the tank... because the timing is advanced a lot more in the diablo tune compared to stock or the 87 tune...
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KDIXER
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RE: Diablo Tune with 87 Octane?

Post by KDIXER »

Is there a difference in part throttle timing between the 87 tune and diablo tune?

When I ran the 87 tune it was a consistent 1.5° to 2° less spark advance than the stock tune on the logs I ran. I compared the spark advance at intervals of 1000, 1500, 2000, 2500 rpm etc...... I have not compared the diablo tune yet.
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06MonteSS
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RE: Diablo Tune with 87 Octane?

Post by 06MonteSS »

huh?? part-throttle timing is the same as stock... you may have been logging/showing less due to a number of reasons... ECT was high, IAT's were high, had KR, etc etc... there are a lot of different reasons/scenarios that timing will get pulled...

the WOT timing is advanced in the 87 tune compared to stock, and the diablo tune is advanced even more than stock/87 tune...
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KDIXER
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RE: Diablo Tune with 87 Octane?

Post by KDIXER »

I ran multiple logs with the 87 tune and it was consistantly 1.5° lower than the factory timing. So I reinstalled the 87 tune with the timing advanced another 1.5°. I even compared them on the same day with the same results.

I have always compared WOT logs so I was not sure if part throttle tiiming was changed or not.

Maybe the U7194 is just to generic. Maybe a tuner more specific to a certain vehicle would be more beneficial than one that is trying to tune a 4.8, 5.3, 6.0, 6.2 and whatever else this thing will tune.

So Monte, are saying that the only thing different between the diablo tune and 87 tune is WOT timing? How many degrees of timing difference is there between the 87 octane and diablo tune?

Does this tool change anything other than timing with the diablotune aside from the parameters the end user can adjust? I know it is supposed to remove TM from the engine which is basically a timing thing from what I can tell.
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RE: Diablo Tune with 87 Octane?

Post by concoursd »

you may have been getting KR and that is why the timing was reduced below stock.
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06MonteSS
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RE: Diablo Tune with 87 Octane?

Post by 06MonteSS »

haha.... it tweaks/adjusts a LOT of parameters, not just timing....

and yes, the only real difference between the 87 tune and the diablo/93 tune is the amount of timing/spark advance...

how much?? dunno.. would have to compare your 87 tune and diablo tune, tune files...

and the tunes ARE specific to a vehicle and it's engine size/type... the settings are not the same for a 4.8, 5.3, 6.0, or 6.2...
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KDIXER
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Re: RE: Diablo Tune with 87 Octane?

Post by KDIXER »

concoursd wrote:you may have been getting KR and that is why the timing was reduced below stock.
Is it possible to be getting KR without it showing up in the TKR when you log?

I juat thought it was odd that the 87 tune had less timing than my stock tune.
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Re: RE: Diablo Tune with 87 Octane?

Post by KDIXER »

06MonteSS wrote:haha.... it tweaks/adjusts a LOT of parameters, not just timing....

and yes, the only real difference between the 87 tune and the diablo/93 tune is the amount of timing/spark advance...

how much?? dunno.. would have to compare your 87 tune and diablo tune, tune files...

and the tunes ARE specific to a vehicle and it's engine size/type... the settings are not the same for a 4.8, 5.3, 6.0, or 6.2...
Monte,

Check out these logs and let me know what you think about the timing.

The Diablo Log is with 87 Octane like I have stated. The only TKR I get is when I stab the throttle but I actually got more of it with the factory tune. The diablo tune has less spark advance than the stock tune until after the 2nd gear shift.

Why would I need to run higher octane and chemically retard the timing if it is less than stock already? I am just trying to wrap my head around this.
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gregs
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RE: Re: RE: Diablo Tune with 87 Octane?

Post by gregs »

just because you logged more knock retard in one data run vs another means nothing. so many things affect the spark numbers your vehicle chooses to run.

chemically retard? ... i don't follow...octane is a rating of resistance to detonation nothing else
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KDIXER
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Re: RE: Re: RE: Diablo Tune with 87 Octane?

Post by KDIXER »

gregs wrote:just because you logged more knock retard in one data run vs another means nothing. so many things affect the spark numbers your vehicle chooses to run.

chemically retard? ... i don't follow...octane is a rating of resistance to detonation nothing else
Trust me, I have logged and compared plenty. I had to add 1.5° spark advance to the 87 octane tune just to get it consistantly close to the factory tune.

You might want to read up on fuel grades a little. Higher octane fuel burns slower than lower octane fuel. That is how it prevents detonation or spark knock. Running high test gas is basically the same as chemically retarding the ignition process. Since it is slower to burn you can get by with running more spark advance since it takes more time for a specific amount of fuel to completely burn.

Think of it this way: You have 2 firecrackers. One with a 8 second wick and the other with a 10 second wick. You have to light the 10 second wick (93 octane) firecracker 2 seconds sooner than the 8 second wick (87 octane) to get them to go off at the same time.
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06MonteSS
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RE: Re: RE: Re: RE: Diablo Tune with 87 Octane?

Post by 06MonteSS »

in some spots/rpms, the diablo tune has higher timing than the stock tune, and in others it does not...

would have to compare your stock tune to the diablo tune to see for sure...

but my educated guess is, that when they developed the tune on the dyno, they saw knock retard in certain spots, so they lowered it a little in the tune file to get rid of the kr.
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concoursd
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RE: Re: RE: Re: RE: Diablo Tune with 87 Octane?

Post by concoursd »

You have the issue partially understood as it pertains to fuel octane. The reason higher grade fuel CAN make more power than lower grade fuel is because the combustion is more stable (slower burn) at higher combustion pressures. Tuning a stock vehicle for more power requires leaning out the fuel mixture and increasing the timing until the combustion is at the most powerful sweet spot without knock. Using higher octane fuel on an untuned stock vehicle is worthless really. There are very few vehicles that will increase timing if using higher octane fuel with stock tuning.

The mix of fuel and spark settings to get the most power will vary. Some engines are tuned from the factory way too rich and with too much timing while others are tuned a little rich and not enough timing. Each vehicle model is different and therefore is independently developed on a dyno and during road testing.

The goal is not to increase spark timing per se. After all, you dont want knock retard and you see more of it with the stock tune which means the PCM is actually pulling timing from the truck as a response and the amount it will pull is not ideal.
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RE: Re: RE: Re: RE: Diablo Tune with 87 Octane?

Post by KDIXER »

Concoursd,

I have studied on exactly what you are saying. And this all started by not "feeling" any performance gain with the 87 octane tune. And that is why I purchased this tuner in the first place, to actually feel a difference.

I guess my thinking is that if I am experiencing TKR then it will show up when I log that parameter. Most of the TKR I see is when I first go WOT from a slow roll or stopped and during shifts sometimes. Which seems normal from all I have read. And I question why I should run higher octane if I am not getting TKR with 87. Because like you said, why run higher octane if the vehicle does not seem to be tuned to require it. I mean I have not changed my comression. And the diablo tune timing is less than or the same as the stock tune. Basically the only thing the Diablo can do is change fueling and timing. So in this scenario, what necessitates the use of high octane?

When I logged my WOT diablo tune using 87 octane, I got a slight amount of TKR and I mean just for a split second. So right now I am running it with -1° in all rpm ranges with no TKR.

I know ideally you want the highest cylinder preassure at about 20° past TDC. I have also read that to adjust timing you advance it until you start to get KR then back it off 1.5° to 2° or until you do not get any KR. I understand performance is dampened when the ecm pulls timing due to KR because it pulls a ton. I have seen it on my logs.
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Ill_Born_SS
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RE: Re: RE: Re: RE: Diablo Tune with 87 Octane?

Post by Ill_Born_SS »

What about quality of fuel ? Is it 87 with additives ? What about altutide? 87 at 5000' is probably only 83.The computer will pull T for that,air density also, wrong fuel trims and PE fueling.
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