Pulley/Tune


Tomcat

GT Owner
I am trying to not bother Rich (GTGuys)...
Back in 2015 I had the GTGuys do a Pulley/Tune at Carlisle (Ford Nationals). In the discussions, Rich said that they use a larger diameter idler pulley to offset the smaller supercharger pulley and keep the tension/slack/etc... in check.
Does anyone know which pulley they "normally" replace? (see drawing below)
 

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twobjshelbys

GT Owner
Jul 26, 2010
6,189
Las Vegas, NV
It's a idler so it won't be ribbed because it's on the flat side of the belt. The numbers on the diagram left side are clipped in the picture but I think it's #13. I know you can reach it from the engine compartment without taking off the access panel on the other side. It's just to the right and down from the snout.


PS. Changing the idler pulley is brilliant. I think the Ford kit adds spacers somewhere (water pump?)
 

Tomcat

GT Owner
It's a idler so it won't be ribbed because it's on the flat side of the belt. The numbers on the diagram left side are clipped in the picture but I think it's #13. I know you can reach it from the engine compartment without taking off the access panel on the other side. It's just to the right and down from the snout.


PS. Changing the idler pulley is brilliant. I think the Ford kit adds spacers somewhere (water pump?)
I kind of assumed it was number 13 too.
 

white out

GT Owner
Mark II Lifetime
Jun 22, 2011
108
Another option is the ATI crank pulley at .3" larger than stock and weighs 10lbs less. So it offers more boost and less rotational mass. But it does require a modified oil pump pulley.
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,281
Me thinks you guys might be over-thinking this a bit! Order a pulley/tune kit from Torrie and be done. Easy-peasy. There are HUNDREDS of Ford GT pulley/tune kits installed with no issues.
 
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Tomcat

GT Owner
Me thinks you guys might be over-thinking this a bit! Order a pulley/tune kit from Torrie and be done. Easy-peasy. There are HUNDREDS of Ford GT pulley/tune kits installed with no issues.
Hey Kendall, My #13 idler is starting to make a little noise and I think I will get one on order until I do other maintenance. I was just trying to determine if its stock (18 years old) or oversized (when the GTGuys did my pulley/tune 10 years ago) and did not want to distract Rich (or Torrie).
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,281
Hey Kendall, My #13 idler is starting to make a little noise and I think I will get one on order until I do other maintenance. I was just trying to determine if its stock (18 years old) or oversized (when the GTGuys did my pulley/tune 10 years ago) and did not want to distract Rich (or Torrie).
Gotcha. I think an OEM idler pulley would be fine.
 

PeteK

GT Owner
Mark II Lifetime
Apr 18, 2014
2,470
Kalama, Free part of WA State
IIRC from the last time I looked at. mine, the tensioner has a fair amount of take-up to allow for wear and dimensional differences. So a small change in the supercharger pulley should be within the take-up of the tensioner.

Kendall, is that about right?
 

twobjshelbys

GT Owner
Jul 26, 2010
6,189
Las Vegas, NV
Hey Kendall, My #13 idler is starting to make a little noise and I think I will get one on order until I do other maintenance. I was just trying to determine if its stock (18 years old) or oversized (when the GTGuys did my pulley/tune 10 years ago) and did not want to distract Rich (or Torrie).

So here's one way to tell if it is stock. When Rich did my pulley/tune he sent me a box of take off parts. The original S/C pulley, the idler pulley, original spark plugs, etc. I don't know if he automatically sends this stuff back but I would assume probably so since lots of people want to revert to stock at some point (I did). So if you don't have a box of takeoffs, then chances are your pulley is original.
 

Tomcat

GT Owner
So here's one way to tell if it is stock. When Rich did my pulley/tune he sent me a box of take off parts. The original S/C pulley, the idler pulley, original spark plugs, etc. I don't know if he automatically sends this stuff back but I would assume probably so since lots of people want to revert to stock at some point (I did). So if you don't have a box of takeoffs, then chances are your pulley is original.
Great point, I do think I have a box of takeoff parts and will review what is in there...although I think at least three pulleys in the supercharger graphic are identical.
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,281
IIRC from the last time I looked at. mine, the tensioner has a fair amount of take-up to allow for wear and dimensional differences. So a small change in the supercharger pulley should be within the take-up of the tensioner.

Kendall, is that about right?
Exactly. When Ford Racing came out with their pulley/tune kit for the GT, they included unique spacers that needed to be placed between the block and the power steering mount. Honestly, not easy to do. But, I suppose there's a rule somewhere within Ford regarding maintaining full travel for the tensioner and these spacers would do just that. However MANY aftermarket pulley tune kits never included these spacers, nor did they include a larger idler pulley... and there has been no adverse consequence of not addressing the very small movement of the tensioner from its intended neutral position.
 

PeteK

GT Owner
Mark II Lifetime
Apr 18, 2014
2,470
Kalama, Free part of WA State
Kendall, thanks for the confirmation.

And Tony, did you get the belt replaced at the same time, that is, did you get the original belt in your box of take-offs?
 

twobjshelbys

GT Owner
Jul 26, 2010
6,189
Las Vegas, NV
Kendall, thanks for the confirmation.

And Tony, did you get the belt replaced at the same time, that is, did you get the original belt in your box of take-offs?
The belt was not changed for the GT Guys 2011 era pulley/tune. The idler pulley made up for the difference in diameter to keep the same position of the idler arm. I can't say what they may have done as time went on...
 

tmcphail

GT Owner/Vendor
Mark IV Lifetime
Apr 24, 2006
4,103
St Augustine, Florida
As Kendall has said above a lot of these have been installed / in concurrent use with the pulley alone and no problems. Best bang for the buck mod there is for this car. In stock and ready to ship as always. https://unleashedtuning.com/ford-gt-sct-x4-2-8-pulley-package/
 

Anderson

GT Owner
May 8, 2021
29
San Diego & FL
Torrie’s tune is awesome! Easy to install with no compromise on reliability.
 

tmcphail

GT Owner/Vendor
Mark IV Lifetime
Apr 24, 2006
4,103
St Augustine, Florida
Thank you :)
 
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Tomcat

GT Owner
Torrie’s tune is awesome! Easy to install with no compromise on reliability.
Agreed, my GT has his tune (done by the GTGuys) and I did another one for my Buddy's GT. No issues in over 10 years.
 
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tmcphail

GT Owner/Vendor
Mark IV Lifetime
Apr 24, 2006
4,103
St Augustine, Florida
Torrie’s tune is awesome! Easy to install with no compromise on reliability.

Agreed, my GT has his tune (done by the GTGuys) and I did another one for my Buddy's GT. No issues in over 10 years.
(y)
 

twobjshelbys

GT Owner
Jul 26, 2010
6,189
Las Vegas, NV
My version of the GT Guys tune (from 2011) was not able to pass OBDII emissions tests. It disabled the O2 sensors and EGR test, maybe more, I don't recall. No check engine light ever came on but the "readiness" indicators said "disabled" so there was no chance of getting through. After several attempts with the tuner I just went back to stock.
 

tmcphail

GT Owner/Vendor
Mark IV Lifetime
Apr 24, 2006
4,103
St Augustine, Florida
My files are OBD compliant and I keep those systems enabled.