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Author Topic: na 2.4 base with gxp rear gear(3.73) questions  (Read 1638 times)

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Offline marksbug

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na 2.4 base with gxp rear gear(3.73) questions
« on: January 17, 2020, 11:15:38 PM »
 I have a 391 in my na 2.4 like all are, its a 2006 so yes it's junk, massive back lash less than 57000 miles. so i bought another rear end.... well the 3rd one to show up was a 07 3.73 with lsd. the first 2 rear end they sent were 1 ,2006 automatic(my car is manual) and 2nd was a jaguar  rear end..... finally a non 2006 rear end with very litle backlash like it should be , and for the torque link car.but 373 gears, so who has done a 3.73 swap into a basically stock 2.4 car and  how much noticeable is it?  Ill have to find somebody to reprogram the speedo if I use it. but I cant seem to find a decent priced 3.91 gear with G80(lsd).  the ratios are oh so close I would think barley noticeable. I realize the car is way under powered already. Ive got a header in the works when i get tyme to build it. and a tune & freer intake breathing too.
   so who has done it and what were the results??? thanks!!! I hate to send this back and have nothing,I dont like having my car down or I would pull it and rebuild it my self, but with no info or even good parts avalibility... I could be walking a long time. yes my solstice is my only car, my 356 speedester is in peices and will be for quite some time( kit car 356 speedster)

Offline Steelmesh

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Re: na 2.4 base with gxp rear gear(3.73) questions
« Reply #1 on: January 21, 2020, 02:08:11 PM »
If you do some searches there is a forum post somewhere that says you can use cadillac CTS (not V) parts for the differential since we share a very similar version with the car. 

In theory, I think the torque loss would be the percentage difference in the gear ratio, so (3.73-3.91)/3.91 = -4.6%, so you'll lose 4.6 percent torque, in theory and the trade off here is gaining that back in speed.
2006 Solstice #1458, Twincharged LE5/LEA, 5757+M62, Werks exh manifold, Tial bpv/wg, Cams, dual meth, 40 PSI, Kappadapt clutch hose/flywheel bolts/trans mount, Aisin AR5, Stage 5 clutch
Turbo-only power 444whp/422wtrq

2013 Cruze Missile, tuned, 42 lb, ZZP SRI/FMIC/DP/MP/CB, Kappadapt trans mount

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