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ausie
01-19-2010, 07:45 PM
I am considering changing the IRS differential housing and found the LPW kit for the 03/04 IRS differential. Is it worth the cost $219.00 ? Looking at the picture of the cover, it appears that the IRS brace may not fit on the LPW cover. Not sure if that would be necessary.

To cover this mod, I may as well change the rear gears too, say 3.73 or 4.10. Cobra does not see the track anymore but may take it to the strip every now and then.

moonlt
01-22-2010, 11:06 PM
With the LPW the brace is not necessary. I have the BilletFlow brace on the stock unit now, and while good it does cause a little leaking based on different bolt tensions, so I am thinking LPW without brace is in my future as well.

ausie
01-23-2010, 02:13 AM
Thanks for your reply moonlt. :thumbsup:

The LPW looks like a nice part and based on the casting, it would be difficult to install a steel brace. From what I gathered so far, the wall thickness is thicker than the stock cover. The only issue I see is that it is a cast alluminum alloy. If the casting is done correctly I am sure there would be suitable strenth in the material. It would be better if the part was billet aluminum since the density of the grain structure is more uniform than that of cast aluminum. Considering the metallugy of the materials used, cast aluminum is from a different grade of aluminum alloy which lacks the tensile strengh of the billet aluminum allowy. I am not saying that the LPW component is a bad part and I am sure it is a good quality component. In my opinion, cast aluminum covers are better suited on cast iron (or steel) axle housings more commonly found on SLA assemblies where loads are not placed directly on the cover of the differential. Considering IRS differential uses the differential housing and cover for support (the flange on the front of the diff housing is strong as well as the overall wall thickness of the carrier assembly is very thick) the weak link is the cover in terms of strength of materials and integrity of the seal. The LPW cover is a lower cost item when compared to the FORE differential cover, it is difficult to compare the two based on structure (cast aluminum vrs CNC billet). I need to look into this in more detail. My goal is to eliminate the need for the IRS brace due to the loading of the part on the differential cover may be of concertn for leaks or other issues. Still undecided.

moonlt
01-23-2010, 12:15 PM
Thanks for your reply moonlt. :thumbsup:

The LPW looks like a nice part and based on the casting, it would be difficult to install a steel brace. From what I gathered so far, the wall thickness is thicker than the stock cover. The only issue I see is that it is a cast alluminum alloy. If the casting is done correctly I am sure there would be suitable strenth in the material. It would be better if the part was billet aluminum since the density of the grain structure is more uniform than that of cast aluminum. Considering the metallugy of the materials used, cast aluminum is from a different grade of aluminum alloy which lacks the tensile strengh of the billet aluminum allowy. I am not saying that the LPW component is a bad part and I am sure it is a good quality component. In my opinion, cast aluminum covers are better suited on cast iron (or steel) axle housings more commonly found on SLA assemblies where loads are not placed directly on the cover of the differential. Considering IRS differential uses the differential housing and cover for support (the flange on the front of the diff housing is strong as well as the overall wall thickness of the carrier assembly is very thick) the weak link is the cover in terms of strength of materials and integrity of the seal. The LPW cover is a lower cost item when compared to the FORE differential cover, it is difficult to compare the two based on structure (cast aluminum vrs CNC billet). I need to look into this in more detail. My goal is to eliminate the need for the IRS brace due to the loading of the part on the differential cover may be of concertn for leaks or other issues. Still undecided.

Yes, you bring up some excellent points. I think the application will dictate your needs in this regard. For my situation, (street and occasion road course), I do not need the level of strength the Fore piece offers; the latter is especially suitable to drag racing and severe initial loads. For me, as the LPW is stronger than stock, eliminates my need for the BilletFlow brace, and I won't be dumping the clutch at high rpms; and, my rwhp will never exceed mid-levels (500-525), I am thinking the LPW unit will best serve my needs without all that extra weight as well as some clearance issues (of the Fore unit).

ausie
01-23-2010, 08:42 PM
From what I gathered, the FORE part should fit as long as you use the stock mounts (not the MM mount). As for the cooler connections, I will not use them at this point. I am basically after the strength of the part and not for the cooling hookup. The LPW part looks like a good component but I think I would like something a bit stronger. I am hard on my car sometimes. I am sure I could get by without the overkill provided by the FORE cover but I would prefer to have that confidence that the differential case is something not to worry about when I go to the strip. I doubt that I will exceed the HP numbers since the front end remains stock as is. I may eventually get a pulley and tune but why bother changing something that is already working fine as is. Since the rear end is going to be worked on, may as well find out what the best gear would be for all around use, both track and strip. 3.55's are good enough but the 3.73 may improve some throttle response a bit. I will be getting a truetrac differential to replace the traction loc stock unit.

moonlt
01-23-2010, 11:24 PM
From what I gathered, the FORE part should fit as long as you use the stock mounts (not the MM mount). As for the cooler connections, I will not use them at this point. I am basically after the strength of the part and not for the cooling hookup. The LPW part looks like a good component but I think I would like something a bit stronger. I am hard on my car sometimes. I am sure I could get by without the overkill provided by the FORE cover but I would prefer to have that confidence that the differential case is something not to worry about when I go to the strip. I doubt that I will exceed the HP numbers since the front end remains stock as is. I may eventually get a pulley and tune but why bother changing something that is already working fine as is. Since the rear end is going to be worked on, may as well find out what the best gear would be for all around use, both track and strip. 3.55's are good enough but the 3.73 may improve some throttle response a bit. I will be getting a truetrac differential to replace the traction loc stock unit.

OK, that would make sense for you. For me, I do have the MM mount, so my situation is different.

puzzle13
01-24-2010, 09:29 AM
Be careful ... the Fore unit is very strong, but due to its thickness it heats up very quickly. I installed the Fore cover prior to going to the clubs track event in New Jersey. I was black flagged in the first 15 minutes for the diff fluid being blown out of the diff tube that was run as they directed to the rear bumper. I then added an expansion tank mounted at the rear bumper and my next session out I was not black flagged, but it still filled the expansion tank and blew out more fluid. I now have a cooler along with an expansion tank mounted in the trunk just below the trunk lid. It still blows out some fluid on really hot days at the track. Granted ... a street car and one at the drag strip will most likely not get this hot as it will never be under the pressure of a car on the road race track for 30 minutes. Justin with Fore did tell of a customer that had the same problem due to highway driving in the summer. For strength ... yes the Fore cover is great. Make sure you put a large expansion tank on the breather tube. Use larger diameter hosing, and make sure it can drain back into the cover and you should be covered.

From what I gathered, the FORE part should fit as long as you use the stock mounts (not the MM mount). As for the cooler connections, I will not use them at this point. I am basically after the strength of the part and not for the cooling hookup. The LPW part looks like a good component but I think I would like something a bit stronger. I am hard on my car sometimes. I am sure I could get by without the overkill provided by the FORE cover but I would prefer to have that confidence that the differential case is something not to worry about when I go to the strip. I doubt that I will exceed the HP numbers since the front end remains stock as is. I may eventually get a pulley and tune but why bother changing something that is already working fine as is. Since the rear end is going to be worked on, may as well find out what the best gear would be for all around use, both track and strip. 3.55's are good enough but the 3.73 may improve some throttle response a bit. I will be getting a truetrac differential to replace the traction loc stock unit.

ausie
01-25-2010, 12:42 AM
I am still considering the FORE part. The expansion tank will be necessary as I do not wish to be spewing fluid everywhere, never mind, my diff leaks already and is alway wet with oil, looked for craks and cannot find any in the case.

What gear oil are you using in the rear differential? If you have issues with overflow, may be the gear oil used. Just a thought not a suggestion.

I found this but may not be the best.
http://www.torcousa.com/technology/RGO.pdf

puzzle13
01-26-2010, 05:32 PM
Ford ... as always have.

I am still considering the FORE part. The expansion tank will be necessary as I do not wish to be spewing fluid everywhere, never mind, my diff leaks already and is alway wet with oil, looked for craks and cannot find any in the case.

What gear oil are you using in the rear differential? If you have issues with overflow, may be the gear oil used. Just a thought not a suggestion.

I found this but may not be the best.
http://www.torcousa.com/technology/RGO.pdf

ausie
01-27-2010, 10:24 PM
Was thinking about the heat and expansion tank issue you are having. I am not sure what you are using as an expansion tank but if it was bottom fed so the oil may return to the differential housing. Also since the expantion tank needs to breath, the top vent should connect to catch can with an air/oil separator so any excess fluids that may pass the expansion tank get trapped in the catch can. There are a tone of catch cans out there, the smallest ones I have seen are sold by steeda (actually any hardware store that sells air compressors have them in different sizes). Most of the catch cans sold by canton or moroso use an internal baffle. I have seen many used for imports that have sight tubes on the side. The worst thing that could happen if you are racing you vehicle is if the hot fluids end up on the brake rotors causing a flash fire. Have you tried to use any other gear oil that meets the ford spec but also has additional additives to reduce heat and foaming? The torco racing gear oil has a type F for ford with the friction additives.