93 octane vs 91 tuned, also 2.67 pulley


GTED

GT Owner
Apr 4, 2006
783
Hi

If I were to buy a GT from outside of California with a 2.67 pulley upgrade and tuned for 93 octane gas, but California only has 91 octane gas, do I have to get the car re-tuned for 91 octane before I have to fill her up for the first time in Ca, or can I drive it with the 91 awhile as long as I don't drive it hard? Also, with the various pulley sizes, is the 2.67 more on the wild side or the mild side? please advise.

thx

Ed
 

RALPHIE

GT Owner
Mar 1, 2007
7,278
In stock form, 91 is the minimum recommended octane - yet the tests on the engine showed it capable of running on 87 if necessary. That is one of the reasons why no knock sensor was included in the engine. Thus, I would assume that a tune requiring 93 would be capable of operating on 91, as long as you don't push the engine too hard. It all depends on the tune that was incorporated with the smaller pulley....
 
Aug 25, 2006
4,436
Hi

If I were to buy a GT from outside of California with a 2.67 pulley upgrade and tuned for 93 octane gas, but California only has 91 octane gas, do I have to get the car re-tuned for 91 octane before I have to fill her up for the first time in Ca, or can I drive it with the 91 awhile as long as I don't drive it hard? Also, with the various pulley sizes, is the 2.67 more on the wild side or the mild side? please advise.

thx

Ed

Hi Ed

All the best on your quest for the right Ford GT

Yes you would be able to drive her on 91 however I would not plan on stretching her legs hard; listen for signs of detonation and if any back out of the throttle and then when time permits have a 91 tune loaded.

As for the pulley size; IMO it is an agressive size pulley and one that you will likely enjoy just keep in mind that the smaller pulley has limitations.

All the best

Shadowman
 

GTED

GT Owner
Apr 4, 2006
783
Hi Ed

All the best on your quest for the right Ford GT

Yes you would be able to drive her on 91 however I would not plan on stretching her legs hard; listen for signs of detonation and if any back out of the throttle and then when time permits have a 91 tune loaded.

As for the pulley size; IMO it is an agressive size pulley and one that you will likely enjoy just keep in mind that the smaller pulley has limitations.

All the best

Shadowman


Hi Shadowman

I have feeling that when I get my GT I'll be calling upon you to tune the car back to 91 octane and perhaps to swap out the current 2.67 to something a little more mild for me, and run the car for awhile before I join the Whipple club. As i learned it from trackdays, when you're new to a new track or a new car to which you're not familiar, power and speed might not be your good friend until you get to know the new car. As such, what would you recommend for a milder pulley size, yet still give me a little more juice that stock?

thx

Ed
 
Aug 25, 2006
4,436
Hi Shadowman

I have feeling that when I get my GT I'll be calling upon you to tune the car back to 91 octane and perhaps to swap out the current 2.67 to something a little more mild for me, and run the car for awhile before I join the Whipple club. As i learned it from trackdays, when you're new to a new track or a new car to which you're not familiar, power and speed might not be your good friend until you get to know the new car. As such, what would you recommend for a milder pulley size, yet still give me a little more juice that stock?

thx

Ed


You are welcome Ed and thank you for the consideration.

I remain willing to answer any questions as you migrate through the process of getting to know her and ultimately making her a member of your family.

In OEM trim they are awesome and from there the sky is truly the limit.

Be safe and take your time getting to know each other.

All the best

Shadowman
 

BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
Hi Shadowman

I have feeling that when I get my GT I'll be calling upon you to tune the car back to 91 octane and perhaps to swap out the current 2.67 to something a little more mild for me, and run the car for awhile before I join the Whipple club.

Hey, Whipple! :thumbsup
 

MAD IN NC

Proud Owner/ BOD blah bla
Mark IV Lifetime
Feb 14, 2006
4,220
North Carolina
Hi Shadowman

I have feeling that when I get my GT I'll be calling upon you to tune the car back to 91 octane and perhaps to swap out the current 2.67 to something a little more mild for me, and run the car for awhile before I join the Whipple club.................
thx

Ed

Leave it at the smaller pulley size - there is a difference between:
1.) stock
2.) stock + tune = 40 HP
3.) stock + tune + cat back = ~ 50 HP and pissing of the neighbors :thumbsup
4.) smaller pulley + tune + cat back = ~75-90 HP (where you are at now called the tipping point) :lol
5.) smaller pulley + tune for 100 Octane + cat back = ~100-110 HP and fun as hell but will create the need for more ("oneHorespoweritist" as Empty says) and the birth of the Whipple or TT monster
6.) Whipple = see web site... As much as 200 HP @ 19 PSI with headers etc.... being FUN AS HELL but will cause excessive spending for tires....

then - Nirvana if you live outside Ca. - the Twin Turbo setup........ where on 93 Octane ~ 850HOP and 116 octane ~ 1000+ HP

last option - Valhalla (ie Joe's set up) being 1,200+ HP where you need a pilots license and have to judge way out in front of where you want to be.....
 

paul b

GT Owner
Nov 2, 2006
810
You may want to find out if they used a hand held tuner, you will need it to bring your tune back to original. It may also have a 91 octane tune available.
 

BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
Well said, MAD_IN_NC! :thumbsup
 

GTED

GT Owner
Apr 4, 2006
783
Leave it at the smaller pulley size - there is a difference between:
1.) stock
2.) stock + tune = 40 HP
3.) stock + tune + cat back = ~ 50 HP and pissing of the neighbors :thumbsup
4.) smaller pulley + tune + cat back = ~75-90 HP (where you are at now called the tipping point) :lol
5.) smaller pulley + tune for 100 Octane + cat back = ~100-110 HP and fun as hell but will create the need for more ("oneHorespoweritist" as Empty says) and the birth of the Whipple or TT monster
6.) Whipple = see web site... As much as 200 HP @ 19 PSI with headers etc.... being FUN AS HELL but will cause excessive spending for tires....

then - Nirvana if you live outside Ca. - the Twin Turbo setup........ where on 93 Octane ~ 850HOP and 116 octane ~ 1000+ HP

last option - Valhalla (ie Joe's set up) being 1,200+ HP where you need a pilots license and have to judge way out in front of where you want to be.....


FUN AS HELL is gooooood, mmuhahahah.... Thanks for the clarifications, all. This forum is great.

Ed
(hope to have FUN AS HELL soon)
 

cobrar1339

GT Owner
Mark IV Lifetime
Feb 2, 2006
956
Diamond Bar, Ca
Leave it at the smaller pulley size - there is a difference between:
1.) stock
2.) stock + tune = 40 HP
3.) stock + tune + cat back = ~ 50 HP and pissing of the neighbors :thumbsup
4.) smaller pulley + tune + cat back = ~75-90 HP (where you are at now called the tipping point) :lol
5.) smaller pulley + tune for 100 Octane + cat back = ~100-110 HP and fun as hell but will create the need for more ("oneHorespoweritist" as Empty says) and the birth of the Whipple or TT monster
6.) Whipple = see web site... As much as 200 HP @ 19 PSI with headers etc.... being FUN AS HELL but will cause excessive spending for tires....

then - Nirvana if you live outside Ca. - the Twin Turbo setup........ where on 93 Octane ~ 850HOP and 116 octane ~ 1000+ HP

last option - Valhalla (ie Joe's set up) being 1,200+ HP where you need a pilots license and have to judge way out in front of where you want to be.....


And that's without the NOS:eek
 

t32b

Verde
Mark II Lifetime
Jul 21, 2007
432
Bay Area, CA
bottom side = f(top side)

Just to add... since the weakest link of the whole car is the tire/wheel combination, there should be as much effort put in to upgrading the bottom side (the tires) as you to the top side (engine).
So I'd suggest you spend a bit of time investigating a tire or better yet, a wheel/tire upgrade when you consider power adds.
OTOH, I have not yet followed my own advice (on either side) yet. So it's the old 'do as I say' thing. :)
 

MAD IN NC

Proud Owner/ BOD blah bla
Mark IV Lifetime
Feb 14, 2006
4,220
North Carolina
Just to add... since the weakest link of the whole car is the tire/wheel combination, there should be as much effort put in to upgrading the bottom side (the tires) as you to the top side (engine).
So I'd suggest you spend a bit of time investigating a tire or better yet, a wheel/tire upgrade when you consider power adds.
OTOH, I have not yet followed my own advice (on either side) yet. So it's the old 'do as I say' thing. :)

Let's also watch the upcoming looming issue many will face in the next year- the clutch! Stock they are quoted to handle ~750/800 HP...... time will tell!

Stillen will be busy is my prediction!