Have a question concerning gear oil... I have a mustang cobra that I currently run a 4.56 gear w/ 31 spline axles & 75w140 weight oil. The car is only summer driven & sees track 4 or 5 times year. My problem is that I believe the 75w140 is costing me some gas mileage & possibly a few horsepower too because of it being "thicker". Because of this concern I have been thinking of switching to severe gear in a "thinner" 75w90 (which is ford spec for 96). My concern is that I will not be getting the same thermal protection & overall protection w/ 75w90 as I would w/ 75w140 I currently run. What do you guys say??? Or do guys think that I should go to the 75w110?? Seems like a good compromise to me, but I'll refer to the experts, what do you guys think??
Question for Pablo and/or Gary Allen
- Thread starter lou_cypher
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I'm not either, but have a question. What 75W-140 are you using now? I like their 75W-110 gear oils.
I'm currently using Royal Purple...But I'm very interested in Amsoil severe gear because of the 75w110. I recently took a 2 hour road trip to Cordova, IL to the race track & I averaged only about 18 MPG...concerning I'm leaving some HP & MPG's on the table. I already know I'm losing some because of the low gear (4.56). Just trying to lose as little as possible, while keeping same level of protection.
Yep the first thought I had is the one Johnny had 75w-110. Did not have that option until a year or so ago.
Better protection than 90wt, but some fuel economy potential as well.
Better protection than 90wt, but some fuel economy potential as well.
I would think the "protection" is more in the EP dopants than the grade. Is this Drag or road course track time?
Mostly drag racing...my main concern is thermal protection...
hmm,
well if your mainly concerned about thermal stability any of the severe gear oil would work well.
I run the 75w110 in the Jeep, and its great stuff. I didnt see a drop in MPG over dino 80w90.
For drag racing, seeing how theres a lot of initial shock on the gears, I wouldn't run anything less than the 75w110, although some might disagree.
You know open lapping on a road course is easier on diff fluid than drag racing!!
Sorry I used to be a corner carver at a couple local tracks. I have a couple buddies that love drag racing though, so I have nothing but respect!
well if your mainly concerned about thermal stability any of the severe gear oil would work well.
I run the 75w110 in the Jeep, and its great stuff. I didnt see a drop in MPG over dino 80w90.
For drag racing, seeing how theres a lot of initial shock on the gears, I wouldn't run anything less than the 75w110, although some might disagree.
You know open lapping on a road course is easier on diff fluid than drag racing!!
Sorry I used to be a corner carver at a couple local tracks. I have a couple buddies that love drag racing though, so I have nothing but respect!
Stick with the 140wt. You need all the film thickness and protection to keep the 'end from breaking.
Another option is to monitor the 'ends temperature throughout the runs to see if you can adjust the gear oil weight for temp.
What 'end? how much HP? .... more info needed but you can't go wrong with a thicker gear oil for protection. There are other places where you can make the extra 2hp that you're looking for.
Another option is to monitor the 'ends temperature throughout the runs to see if you can adjust the gear oil weight for temp.
What 'end? how much HP? .... more info needed but you can't go wrong with a thicker gear oil for protection. There are other places where you can make the extra 2hp that you're looking for.
under 400hp i would think Durablend 80W-90 would be fine, or you could go to Redline Shockproof or other good oil
UnDummy has very good points.
Just so everyone knows, Gary and I answered with 75W-110 (in a PM)
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