RandomHero

iTrader: (24)

I have to disagree with you that higher octane is useless running through our trucks, but that aside, nice numbers.

NicD

iTrader: (7)

It's pretty much the same. After I did the cam I drove the same stretch of the freeway that I always do and reset the average on the DIC and it read pretty much the same afterwards. Driving in the city with stop and go was pretty much the same as well.

Silverado53

Wow, those are some very impressive gains! Is the truck still responsive to throttle input at different speeds?

Jeteys5.3

iTrader: (4)

good to know.

NicD

iTrader: (7)

I saw no higher gains when I increased the timing above 26 degrees and it still didn't ping at all on 87 octane. You can disagree if you want but if that doesn't say something to you I don't know what would.

Like I said, 9.5 to 1 compression is pretty low and you really aren't going to gain much if any by running a higher octane gas and trying to feed timing into a setup that is pretty much optimized for 87 octane to begin with. Only time I have seen good gains with tuning for 91 octane is with the higher compression versions of the motors in the trucks.

NicD

iTrader: (7)

Yes, honestly it drives like stock.

RandomHero

iTrader: (24)

I guess it's going to vary from person to person. I'm curious to hear the opinion from people who have tuned hundreds of trucks. Speaking from personal experience I was able to run quite a bit more part throttle and WOT timing switching from 87 to 93. I don't have a ton of track time but efficiency was greatly increased. Under the same conditions I saw almost 3 mpg difference on the highway.

dlt76028

iTrader: (13)

i stopped running 93 in my truck too. my compression is right at 10.0 and i'm running 26-27 degrees timing and switching to 87 i saw no knock at all and felt no difference.

good numbers btw.

NicD

iTrader: (7)

I've been doing this for 8 years now and honestly I have lost count of how many vehicles I have tuned. I have tried adding timing all over with higher octane and just doesn't see a big benefit regardless if it takes the timing or not on the lower compression stuff. I saw all of a half mpg difference in gas mileage by adding up to 8 degrees or more in the part throttle areas and hardly any difference on the dyno at WOT either. I am talking about the difference between tuned 87 vs 91, not what it comes from the factory with vs what you can add because that is a good amount. Then again I am not selling people 91 octane tunes and claiming big numbers so I have no motive behind advertising.

RandomHero

iTrader: (24)

I wasn't aware of your credentials, my apologies . It's a pretty interesting topic. I may start a new thread to see what everyone else has to say. Like I said, I have no track times to compare.

As far as knock, I'm running 29* at WOT. I don't see knock until 32* or so (I'm aware of the law of diminishing returns on the matter) . I have not tried to fill up with 87 to see if it sees knock or not. Perhaps that test will happen when the local track opens up.