I put under drive pullies on my new edge GT. Definitely makes the engine more peppy and rev faster. Well worth it. Add off-road x pipes with flowmasters, cold air intake with 75 mm plenum intake, and 4.10 gears and you have a fun 2003 Mustang GT. People be surprised how quick my “old mustang” is.
@@latemodelrestoration So just out of curiosity, what if you get the underdrive crank pulley, and cobra water pump pulley and cobra alternator pulley? That will be the smallest diameter of all 3.... Just curious
I have underdrive pulleys on my 347 5.0 / Fox-based engine in my Factory Five Cobra and I seem to have trouble with cooling in stop and go traffic. I suspect it's because the water pump is turning a lot slower. The headlights also dim at the stoplight.
What size belt did you use? I’m thinking about a 93 cobra pulley upgrade, only mod is a deleted smog pump, I wonder if a 84.5” belt will work with cobra pulleys and deleted smog
Hey man I know this is a old comment but I’m interested in running that cobra pulley/smog pump bypass combo as well. Did you ever figure out what size belt it was?
Looks like a stock alternator in the vid. FWIW I ran under drive pulleys for years on my Fox with a 3G alternator and the volt gauge never flinched under load.
@@BlueOvalTavern did you also run electric fans? I'm trying to figure out if I should run underdrives with an electric fan, 3g alternator as well as a couple of subs. Just wondering if I should go with the 130amp or the 200.
@@GreenToFeelBlue I've never used an electric fan. A 130 amp would most likely run just fine even with underdrives, but I would probably get a 200 amp since the price bump isn't much and to make sure it would provide for the subs.
Can't thank you guys enough for excellent prices, quality, and customer service. (Big thanks to John)! I have actually received items the next day from you guys! Just wondering if you have any plans to make the Cobra pulleys out of steel, anodized black?
Hi Jesus, With the installation of the underdrive pulleys, we do recommend upgrading the stock alternator, due to the difference in diameter size from stock. You can email or call us using the link below for more assistance: lmr.com/contact
When the pump is spun too fast, cavitation occurs (air bubbles) and flow drops dramatically, you plan to drive it like you mean it then there is no drawbacks, for idling and Sunday drives maybe not the best
Great info for sure, fact is pulleys do make power, love the OG fox mods!
OG Fox mods for the win all day!! 🙌
I put under drive pullies on my new edge GT. Definitely makes the engine more peppy and rev faster. Well worth it. Add off-road x pipes with flowmasters, cold air intake with 75 mm plenum intake, and 4.10 gears and you have a fun 2003 Mustang GT. People be surprised how quick my “old mustang” is.
@@latemodelrestoration So just out of curiosity, what if you get the underdrive crank pulley, and cobra water pump pulley and cobra alternator pulley?
That will be the smallest diameter of all 3.... Just curious
Those Cobra pulleys along with a 3g alternator upgrade should do the trick! Thanks to Brew2L and Foxcast for pushing out the additional info !
Yeah that was my question, pulley size difference between 3g alternator upgrade and under drive alternator pulley for the cobra style
Impressive results . That’s actually nice back for the buck.
I have underdrive pulleys on my 347 5.0 / Fox-based engine in my Factory Five Cobra and I seem to have trouble with cooling in stop and go traffic. I suspect it's because the water pump is turning a lot slower. The headlights also dim at the stoplight.
yes, they usually run hot
Any fix besides going back to stock?
Lower temp thermostat
Excellent info! Next could you do a video showing the power gains for a efan on a foxbody!?
and then you need $400 alternator upgrade to pull the extra 30 amps.
itza money snowball
Running LED headlights with underdrive pullies should return it to 12.6v perhaps?
should be around 13.8
Are there different pulley options for a 351w or would these options swap?
What size belt did you use? I’m thinking about a 93 cobra pulley upgrade, only mod is a deleted smog pump, I wonder if a 84.5” belt will work with cobra pulleys and deleted smog
Hey man I know this is a old comment but I’m interested in running that cobra pulley/smog pump bypass combo as well. Did you ever figure out what size belt it was?
Very good test.
I may have missed it but was that with a stock or a 3g alternator?
Looks like a stock alternator in the vid. FWIW I ran under drive pulleys for years on my Fox with a 3G alternator and the volt gauge never flinched under load.
@@BlueOvalTavern did you also run electric fans? I'm trying to figure out if I should run underdrives with an electric fan, 3g alternator as well as a couple of subs. Just wondering if I should go with the 130amp or the 200.
@@GreenToFeelBlue I've never used an electric fan. A 130 amp would most likely run just fine even with underdrives, but I would probably get a 200 amp since the price bump isn't much and to make sure it would provide for the subs.
Can't thank you guys enough for excellent prices, quality, and customer service. (Big thanks to John)! I have actually received items the next day from you guys!
Just wondering if you have any plans to make the Cobra pulleys out of steel, anodized black?
We appreciate the feedback! Thank you!
Not at this time. Maybe in the future!
Great video!
Thank you
With the sve pulleys the belt is the same?
Not exactly. Here's a guide for more information: lmr.com/products/fox-body-belt-routing-length-50
will the belt size change when doing the underdrive pulleys i am interested in doing this.
The 1993 Cobra-spec pullies will require a shorter length belt. Standard underdrive pullies for Fox Mustang do not. -Landan
Was it a stock alternator?
I prefer a lightweight stock diameter pulley. Uses the stock belt and don't have to worry about any charging issues.
Where can you find lightweight stock diameter pulleys? I would be interested in those.
Should these pulleys cause me to lose alternator charging power?
Hi Jesus,
With the installation of the underdrive pulleys, we do recommend upgrading the stock alternator, due to the difference in diameter size from stock. You can email or call us using the link below for more assistance: lmr.com/contact
Great video! This is a age old debate that is now proven for all the haters lol
Nice wheels what are those??
They're our SVE Mesh Wheels. Here's the link: lmr.com/products/mustang-sve-mesh-wheels-79-93
@@latemodelrestoration very nice wheels, I’ve swapped to five lug but thank you!
What happens when underdriving the water pump?
the wather pump works bether at high rpm's then thats what is happening
gets hot on marginal days
When the pump is spun too fast, cavitation occurs (air bubbles) and flow drops dramatically, you plan to drive it like you mean it then there is no drawbacks, for idling and Sunday drives maybe not the best
Fit 94-95 cars?
No, 79-93 only
and then it runs hot
If you were concerned with the voltage you would have changed to a 94+ alternator by now
He could have cooling issues as well now. I say leave the factor pulleys on there.