oldguy05gt

I bought an '05 GT from a Ford dealer in Carlsbad, California. I wanted the supercharger option they offered to install, so I had them do it. It is the basic Vortech VQ S-2 model - bothcar and supercharger under dealerwarrantee.

My supercharger knowledgestopped around 2000, so this isnew info with learning curve for me:

The Accessories Supervisor is therewhen I pick up the car. He says I "have to" run 93 octane now, and that he went down the street and got me a full tank of 93. I asked about the "numbers" on the dyno, (I assumed). He said they don't use a dyno, but use the Diablo Predator, which he had in a box for me just like it came from a store - no other data available.

So right away I have 3 problems. The GT owners manual says I have to use 87 octane, the lowest grade California gas, which is 87, 89, 91 rated.

I just got told I have to use 93 octane, which although apparently this dealer can get, I'm in Fallbrook about 35 miles away and there's nothing here - we're lucky to have a couple of gas stations,lol. I'm not going to drive 35 miles or more to find 93 octane, so why didn't they tune the car for 91 octane, or at least phone and ask me. They seem like very nice people and just wanted me to be happy with the results, I think. The car goes like h*** but I haven't driven it much yet, and when this tank is gone??

Will not using 87 octane like the manual calls for damage my engine?

Will not using 93 octane like the supercharger calls for, but using the available 91 octane damage my engine?

If 91 octane is okay for just normal driving around, willitcause engine damage if I run it up to redline street racing around the county for fun?

And last but not least I have no "numbers" or results to relate to, just this Diablo Predator which I know nothing about.

I know I'm not the only one with this bunch of of questions, so any info or suggestions will be appreciated.

Thanks in advance!

EricM

The answer to the question about using higher than 87 is you can ignore the manual, it definitely won't hurt anything.

The other questions are harder to answer. The tune that comes from Vortech is for 91 octane. Most likely, the dealer just used that with the Predator that came in the kit and called it done. There's no guarantee, but without a dyno it seems highly unlikely that they did any custom tuning. Ask them exactly what they did.

exx1976

I'd find a dyno and get a REAL tune. And DEFINITELY do that BEFORE you start romping on it.

Using 87 will *likely* cause damage in the form of detonation. I certainly wouldn't do it.

Running an octane HIGHER than what is reccommended will not cause damage. At worst it will be a waste of money. But, since you were todl to run 93, then the only thing you could waste money on would be race or av gas..

Argonaut

Sorry if you already know thisbut it sounds like you would like a bit of info on what a "Tune" is and what the Diablo Predator does. The basics: Your car has a computer in it, commonly called a PCM (Powertrain Control Module). It controls a host of engine and electronic management functions. Like any other computer it has a software program. The Predator is a tool that allows you to load a new software program (a "Tune") into the PCM. The Predator connects to your car via a port right under your steering wheel. Some of the functions the PCM controls are timing and air/fuel mixture. As you probably know, Octane makes gas harder to detonate. So by using 93 Octane gas instead of 87 it means you can advance the engine's timing and lean out the air/fuel ratio (producing more power)without running into pinging and destructive detonation inside the engine. The Predator probably has multiple tunes, i.e. it probably came with the 93 Octane tune + one or two others. It sounds like the Dealer simply installed the 93 Octane tune for the reason that it would produce the most power. Since no Dyno was used, it means you are using a "stock" or "off the shelf"tune. A tune that was developed by someone (the vendor of the Predator?), presumably this stock tune was developed for a supercharged engine. It might be that the Predator has other lower octane tunes in itand they could be appropriate for your application. You should ask the Dealer. To load a new Tune is simple. Just turn off the car, plug the Predator in and follow the on-screen instructions.

HOWEVER - in spite of the above, the best and safest route for you to go is to find a performance shop with a dyno and have them "custom" tune your car, i.e. develop a tune for it that meets the specifics of your car and at a lower Octane...probably 91.

EricM

Just to clarify, if there are multiple tunes in your Predator from Vortech, those aren't for different octanes. That's for non-cooled, air-air cooled, air-water cooled. Their tunes are all 91 octane. Call them, e-mail them, or download the manual and check if you're worried.

Call the dealer before you head to a dyno shop. Preferably the one that actually installed it, and talk to the service manager there, since the manager you've been talking to doesn't seem to be all that full of clues. If you want the tune optimized (for performance), then by all means get to a dyno. You will technically be voiding the warranty you got (wasn't that a factor in getting this particular SC?), but there are ways around that. Just don't assume you need to make changes and something isn't safe for 91 octane until you find out exactly what they used for a tune. If the tune came from Vortech and you're happy with the power, then there's nothing else you need to do. It was developed for 91, and it's probably more conservative than anything else you'll get.

oldguy05gt

Thanks for all the good info. I found out the subcontractor that did the actual work and Diablo/Predator tune and am going to get together with him. Actually the warrantee wasn't that big a deal for me, it's just that they made a big deal out of it, so why not, no extra charge.

I've been doing a lot of reading on the Vortec supercharger which is their basic model,and it seems like since I have alittle $$ left over, it would have been nice todo the high output aftercooler setup. I don't know how much that would cost me now to add on, but I'll find out (ouch). Other than that, axle-backsa little louder than stock thatadd a few hp is all I'd put on. Dyno with new Predator tune, yeah.. o'well, lol. The car is faster thanh*** now just driving around town. I got an auto as my left knee and hip are shot - when I step on the gas all I can hear isVOOM clik clik clik when the tranny shifts - very fast shifts. If there's much power lost with the atx it's made up for in shift time and not having to worry about missing 3rd gear, LOL.