Pulley and Tune


PHXGT

GT Owner
Mark II Lifetime
Sep 11, 2005
369
Phoenix, AZ
Do all the pulley and tune kits (and associated MAF sensors) cause the boost gauge to become inaccurate? Or, do some of the kits include re-flash software that adjusts the boost gauge?

Thanks for your input.
 

twobjshelbys

GT Owner
Jul 26, 2010
6,053
Las Vegas, NV
Do you have the GT Guys setup? I've asked Rich if his tuner has a solution. I've also asked him for a 91 tune that leaves the O2 sensors and EGR on since I don't thiink they need to be turned off if you have a standard or FRPP exhaust.
 

PHXGT

GT Owner
Mark II Lifetime
Sep 11, 2005
369
Phoenix, AZ
I don't have a pulley and tune yet. Just heard that some of them leave the boost gauge useless, and wanted to know if they all do or just some. I'd like to find out if there are choices that still allow the gauge to be accurate before I take the plunge.
 

MAD IN NC

Proud Owner/ BOD blah bla
Mark IV Lifetime
Feb 14, 2006
4,211
North Carolina
I don't have a pulley and tune yet. Just heard that some of them leave the boost gauge useless, and wanted to know if they all do or just some. I'd like to find out if there are choices that still allow the gauge to be accurate before I take the plunge.

If more than 15 PSI is generated, the stock gauge will peg... Get a Britto guage as it tops at 30 PSI, and is 100% stock looking
 

twobjshelbys

GT Owner
Jul 26, 2010
6,053
Las Vegas, NV
The one I have changes the MAF (the GT Guys setup) and I get a negative offset. My boost gauge sits fully in the vacuum range (I really don't remember, -15?) and is pretty much at 0 at full (16 PSI) boost. The native boost is "inferred". Based on switching the MAF back to reload the factory tune the contributor to the offset is the pulley itself. Someone else here just mentioned this recently too.

The Britto gauge as I understand it is an actual measure taken from a port in the supercharger, correct?
 

Xcentric

GT Owner
Mark II Lifetime
Jul 9, 2012
5,213
Myakka City, Florida
1st question. No. 2nd question. IDK.

My tune adds 4 psi and pegs the boost gauge at WOT. The gauge behaves normally.
 

jcthorne

GT Owner
Aug 30, 2011
792
Houston
My pulley and tune did not require MassAir sensor modification. My boost gauge works normally although it does peg at the very top end. (I am seldom looking at the gauge during those brief moments.....)

For a pulley on the stock blower, mods to the MassAir and fuel system are really not needed. End of range to be sure. Moving up to a Whipple or other blower, yes as you go well beyond the stock ranges.

I used a steel pulley from Steeda and had Torrie tune the car.
 

FBA

GT Owner
Dec 5, 2010
1,663
31.022340° N / 44.846191° W
Once you get to 15 PSI, you're done. Once you install anything that adjusts voltage for MAF in order to allow more boost and not crap out, your gauge is useless. I run 23 PSI with my Whipple and I'm using the gauges from Speedhut with their boost gauge and sensor.
 

tmcphail

GT Owner/Vendor
Mark IV Lifetime
Apr 24, 2006
4,102
St Augustine, Florida
If you don't use a mass air modifier then normally your boost gauge won't read inaccurately. There are different ways to scale it so that does not happen if you opt to use one. I can handle it either way.

http://www.unleashedtuning.com/ford-gt/
 

texas mongrel

GT Owner
Mark II Lifetime
May 3, 2009
1,661
Houston Texas
Hefner pulley, Torrie tune, everything works fine.
 

tmcphail

GT Owner/Vendor
Mark IV Lifetime
Apr 24, 2006
4,102
St Augustine, Florida
Hefner pulley, Torrie tune, everything works fine.

Your car did damn good too!
 

texas mongrel

GT Owner
Mark II Lifetime
May 3, 2009
1,661
Houston Texas
614 at the wheels on "the most conservative dyno in town". I am a happy camper!
 

tmcphail

GT Owner/Vendor
Mark IV Lifetime
Apr 24, 2006
4,102
St Augustine, Florida
Big time, that was a feat in itself.
 

PHXGT

GT Owner
Mark II Lifetime
Sep 11, 2005
369
Phoenix, AZ
Torrie, Does your set up use a larger idler pulley or shims? What are Hp gains with your kit and do you have a 91 octane tune?

Thanks.
 

tmcphail

GT Owner/Vendor
Mark IV Lifetime
Apr 24, 2006
4,102
St Augustine, Florida
Stock belt and idler remain.
Most are 620WHP on 93 slightly less with 91 octane
I can build calibrations based on whatever fuel you plan on using
 

PHXGT

GT Owner
Mark II Lifetime
Sep 11, 2005
369
Phoenix, AZ
Torrie,

Thanks. Sent you a PM.
 

texas mongrel

GT Owner
Mark II Lifetime
May 3, 2009
1,661
Houston Texas
PHXGT, don't worry about the idler/shim issue, I've got 26K miles on mine with no problems. Heck, you don't even have to take the belt off when fitting the pulley!
 

tmcphail

GT Owner/Vendor
Mark IV Lifetime
Apr 24, 2006
4,102
St Augustine, Florida
Quite true.
 

TO AWSUM

Ford GT Owner
Mark II Lifetime
Jul 4, 2007
1,506
Niceville FL
Thank you for this post. It saved me some future heart burn about the gauge not reading properly.