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WTB lower ratio diff (3.27) [CA, USA]

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WTB lower ratio diff (3.27) [CA, USA]
#1
GT6 Parts Spitfire Trade Wanted
69 Spitfire 12a Avatar
69 Spitfire 12a Chris S
Gilroy, CA, USA   USA
Does anybody have a 3.27 diff they want to trade for a 4.11?

my differential so far hasnt let me down, and I drive my spitfire quite a lot. I just want a lower ratio



Edited 1 time(s). Last edit at 2019-02-12 05:54 PM by 69 Spitfire 12a.

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Tonyfixit Avatar
Tonyfixit Tony M
Duncan, BC, Canada   CAN
Hope springs eternal.

Well good luck anywaythumbs up

billspit Bill Kea
Moore, Spartanburg, SC, USA   USA
Unless you have a Spit6, a Spitfire doesn't have enough oomph to pull a 3.27. I put a 3.63 in my Mk I and it wouldn't pull a hill well.

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Tonyfixit Avatar
Tonyfixit Tony M
Duncan, BC, Canada   CAN
In reply to # 1595067 by billspit Unless you have a Spit6, a Spitfire doesn't have enough oomph to pull a 3.27. I put a 3.63 in my Mk I and it wouldn't pull a hill well.

Not necessarily, it would be like having an O/D permanently engaged, it might be a little slower off the line, but once going you would just stay in the lower gears more.

arturo64 Avatar
arturo64 Arthur T
Billings, MT, USA   USA
I think the torque of the motor would play a huge part in driving a 3.27. a torquey 1500 compared to a high rev 1100.... what might a rotary have for torque value??? dunno. but I'd add that a 3.89 could be had fairly easily and cheap, if you keep your eyes open. give that a try and see how it feels, still not happy? then search for 3.27



Arthur
68 spit
70 gt6+



Edited 1 time(s). Last edit at 2019-02-08 05:12 PM by arturo64.

quikrx Ralph Hansen
Antioch, IL, USA   USA
1962 Triumph Herald 1200
1969 Triumph Spitfire MkIII "Gloria"
1987 Mazda RX-7 "Mistress"
2003 Toyota Celica GT-S "Natasha"    & more
a rotary motor is very torque less - they love to rev even more than an 1147/1296 - to go quick you need that 4:11 - a rotary will spin easily to 10k if properly built, otherwise they are good to about 8k easily

know them pretty well, race a 12A

Ralph

69 Spitfire 12a Avatar
69 Spitfire 12a Chris S
Gilroy, CA, USA   USA
The GT6 is said to actually make very similar torque to the SA Rx7 (first gen, what my motor is from)

SA rx7 is 115 lb ft
GT6 is 117 lb ft

and those should be rated differently since the gt6 was rated with gross power, and the Rx7 was rated with net power

I do kinda forget that 12a isnt a term everyone is acquainted to, my car is engine swapped. Especially with the Rx7 transmission the gearing on this car is too short.

really the biggest factor I forgot about was that the tyres are far smaller, which changes the gearing. (since the trans is from a rx7, and the diff ratio is the same as one.)


These are the transmission's ratios for reference
Application 1st 2nd 3rd 4th 5th
79-80 RX7 3.674 2.217 1.432 1.00 .825

I can go do the math to figure out what diff id need to have the same ratios as the stock rx7 but 3.27 probably isnt that far off



Edited 2 time(s). Last edit at 2019-02-09 12:12 PM by 69 Spitfire 12a.

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