A few questions about octanes

[sircolby45]

I am using a U7194 predator on an 08 Chevrolet Silverado(4.8L) and I believe it is revision 9r05a(or something along those lines).

I have read a lot that the diablo performance tune is designed for 91/93 octane. On the U7194 description it states that 91 octane is for corvettes only:

93 Octane Performance Tune
91 Octane Performance Tune,Corvette Only
87 Octane Performance Tune,Truck & SUV only

Does this mean that if I install the performance tune on my truck that I must run 93 octane? Another question is what kind of damage would I be looking at if 87 octane was put in accidentally with a performance tune? The reason I ask is I don't want to get my head in the clouds one day at the pump and by habit put in 87 octane and ruin my engine. As you can probably tell I am very weary about hurting my baby .

Also I am considering getting flowmasters some time in the future and am wondering if this is going to affect my tune.

Edit: Also what would be a safe maximum speed to enter into it without over revving the engine? Also whenever I installed the tune(currently 87 octane) I noticed that for a little while my door ding did not sound right...Is this normal? It sounds like it always has now.

[06MonteSS]

no.. the TRUCK tunes are made for 91 octane or higher.. .so, you have to use at least 91 octane gas...

that's why you only have a choice of the performance tune and 87 tune... and not a separate 91 octane tune... because the performance tune for trucks IS the 91 octane tune.

[sircolby45]

no.. the TRUCK tunes are made for 91 octane or higher.. .so, you have to use at least 91 octane gas...

that's why you only have a choice of the performance tune and 87 tune... and not a separate 91 octane tune... because the performance tune for trucks IS the 91 octane tune.

Thanks for clearing that up! You make Diablo's tech support guys jobs a lot easier lol.

Another question that I have is I currently have a K&N air filter and am planning on putting a flow-pro muffler in and was wondering if this is going to require a custom tune or if it is still within the acceptable limits. I'm a college student so the reason I am asking is because I can't really afford a custom tune yet.

Thanks again for all of your help!

[06MonteSS]

nope... no need for a custom tune...

just do some logging and get your LTFT's dialed in to the proper range via the injector slope adjustment...

http://diablosport.com/index.php?name=P ... opic&t=917

[sircolby45]

nope... no need for a custom tune...

just do some logging and get your LTFT's dialed in to the proper range via the injector slope adjustment...

http://diablosport.com/index.php?name=P ... opic&t=917

I have my interface kit ordered so I will do that whenever it gets in. I don't have my muffler yet, but I may go ahead and dial it in so I can for one get the hang of it and two maybe it will be a little closer whenever I go to dial it in with the new muffler. I have the U7194 with the short log time, but luckily I have a laptop, so I should be good there. Thanks again for your help.

[sircolby45]

Well I just did a run with it and just read the numbers with the predator in hand. The LTFTs pretty well stayed in the -1.5 range and there was 0 KR even at WOT, so until I get my muffler I think it may be pretty well dialed in.

[06MonteSS]

yep.. .sounds like it...

[BigBlueRado]

You ought to check out my exhaust clip on youtube, just look up my user name. As soon as I clean her up again, i will be doing a few more clips.

[sircolby45]

You ought to check out my exhaust clip on youtube, just look up my user name. As soon as I clean her up again, i will be doing a few more clips.

Actually I already got my exhaust on.(Had them installed yesterday) I ended up going with a flo pro and dual exhaust with 4 in tips. I am very pleased with it. I ended up with exactly the sound I was going for.

Now all I've got to do is wait on my interface kit to get here and get to tuning. I think it is supposed to arrive today.

[sircolby45]

Well I got my cable in and tested the LTFTs and they are still averaging -1.5. Is the PE logging/adjusting still necessary?

Edit: Ok now that I am home I can post my log file. As you can see from it I drove for a while with my RPMs below 1800, but I corrected it about half way through the log. The reason is my truck has a 3.23 rear end so it doesn't run 1800 RPMs at 70!

[CANUCKPREDATOR]

log in a lower gear to get RPM up

[sircolby45]

log in a lower gear to get RPM up

Well I just bumped it up a few MPH to get the RPM above 1800...Would that be ok?

[06MonteSS]

yes, that's fine..