LS1less

Couldnt they squeeze more power out of the 4.6 by giving us a 91 tune from the factory? It would only be like $3 difference at the pump! What was they primary reason to deTUNE the 4.6 with 87 octane? I tried running premium & regular but there was no extra throttle response/ power output.

Gene K

It already makes 310 bhp on Premiumfor late 2005+. Ford Powertrain Engineer at 2005 intro stated the cars make 4-6 hp more on Premium. Also the vapor trap was removed from the intake tube after 2005 which added 4-6 more. Most dyno results also show 4-6 hp more on Premium but your not going to feel that. If you want to get rid of the soft response you need a tune just like the LS2 and LS3 boys. On the 2008 pcm they have allowed the PCM more headroom so it can advance the timing more yet.

PS My car consistently trapped 1 mph slower on 87 than 93 when stock.

mynameismike65

Because Ford figured that the majority of buyers would keep it stock and us it as a DD and if you were seeking more power you would go aftermarket anyways and do the intake/tune combo. It looks alot more appealing to average joe when it says 87 octane rather then 91 or 93. With gas prices as high as they are now that would scare potential buyers away faster then it being a gas sucking V8 alone. Plus 91 isn't available everywhere. Is it that big of a deal spending ~550 on a JLT/Brenspeed tune? That would be better for the money then a Mustang tuned from the factory at 91 with the stock airbox. Why stop there.....why couldn't Ford have sold the new S197s with 1 piece aluminum driveshafts, UDP's, better intake, CMCV plates, 4.10's, or forged internals for that fact? theres alot of stuff they could have done from the factory to squeeze every pony out of the 4.6 but didn't.....and if they did alot of us on here wouldn't have anything to do on their Saturday mornings

moosestang

Buy an intake and tune!

Not everyone has 91 available. I only have 87, 89 and 93. Higher octane is not going to change throttle response.

Buy an intake and tune!!!

VistaGT

+1

Mikes_BLK_GT

+2


On a side note technically Ford does offer a 91-93 tune, it comes with the FRPP packs that they offer. Ofcourse you have to spend way to much on a steeda cai and some other stuff to go with it.

doogyhap

With the way gas prices are most people prefer to fill up with only 87 octane. Of course I am not one of them.

MexGT

No use for a 9.8:1 CR engine ...

If we had a 11.0:1 CR engine a 91 octane would be a MUST.

acascianelli

Because people don't like having to pump premium gasoline.

howarmat

agreed, its easy just to make it run on 87 from the factory.....there are TONS of people out there that wouldnt read the manual or see that it needs 91, you would have half the mustangs owners messing their cars up and then taking them to FORD and asking what the problem is. And in times like this people would fill up with 87 because its cheaper even if they did know it was suppose to take 91.....they would assume "gas is gas, right"