diff quart mile question?

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Badazzsr20
240sx Wannabe
Posts: 140
Joined: Wed Sep 09, 2009 8:35 pm

diff quart mile question?

Post by Badazzsr20 »

hey guys,

i went to the track this pass week and i did a 11.0@134 witch is great personal best. but i have a question im running 4.11 gears in the rear right now and im going pass the traps at about 6500 maybe alittle higher like 7k im not shifting into 5th so im good. but i have a 3.69 diff that my friends are telling me to install my question is if i install this diff (3.69) gear will this change my mph at the track will it go up or down. i hear that u want the gear to be almost at the rev limiter as u pass the traps.thats how it is now if i add this diff i might be going pass traps at 5k 6k mark maybe?

i dont wanna change the diff to a lower gear if its not going to help me. i think if i add it that might hurt me cause now i wont be crossing the traps at or close to the limit anymore. can anyone please help me out with my question? will this make my car trap higher then 134 with the 3.69 gears or will it stay the same ill just go pass that trap at 5 t 6k and still be a 134 car?

thanks for any info on this guys :D
RosadoRacing
Dont Question My Nissan Knowledge
Posts: 541
Joined: Tue Apr 06, 2010 5:33 pm
Location: Bethlehem, PA

Re: diff quart mile question?

Post by RosadoRacing »

leave the 4:11 in. When you run out of gear than you go to a taller gear but 3.69 are too low unless you have 800+whp.
Kisor
Driving Mom's Station Wagon
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Joined: Sat Jan 19, 2013 5:41 am
Location: Cincinnati, Ohio

Re: diff quart mile question?

Post by Kisor »

What size tire are you running and what are your 60' times? 134 is a big trap for 11.0.

3.69 isn't a huge change but you have more ET on the table with the 4.11. J30 diff is 3.96 and will allow you another 10-12 mph or you can go up in tire size which will prob help 60' and first 330.
RosadoRacing
Dont Question My Nissan Knowledge
Posts: 541
Joined: Tue Apr 06, 2010 5:33 pm
Location: Bethlehem, PA

Re: diff quart mile question?

Post by RosadoRacing »

He's either bogging off the line or slipping the clutch. I once ran 11.08 @ 136 with a 1.8 60ft cuz I slipped the clutch
Badazzsr20
240sx Wannabe
Posts: 140
Joined: Wed Sep 09, 2009 8:35 pm

Re: diff quart mile question?

Post by Badazzsr20 »

Kisor wrote:What size tire are you running and what are your 60' times? 134 is a big trap for 11.0.

3.69 isn't a huge change but you have more ET on the table with the 4.11. J30 diff is 3.96 and will allow you another 10-12 mph or you can go up in tire size which will prob help 60' and first 330.
im running 26" tall MT and i the 300z diff with j30 axles. so ur telling me if i put the j30 diff or the Q45 3.69 ill pick up 10-12 mph more in my quart mile passes?
Badazzsr20
240sx Wannabe
Posts: 140
Joined: Wed Sep 09, 2009 8:35 pm

Re: diff quart mile question?

Post by Badazzsr20 »

RosadoRacing wrote:He's either bogging off the line or slipping the clutch. I once ran 11.08 @ 136 with a 1.8 60ft cuz I slipped the clutch
yea i was slipping the clutch alot cause i was worried about breaking the j30 axles i got.
RosadoRacing
Dont Question My Nissan Knowledge
Posts: 541
Joined: Tue Apr 06, 2010 5:33 pm
Location: Bethlehem, PA

Re: diff quart mile question?

Post by RosadoRacing »

You have the same exact rear set up as me. I've done multiple 1.4 60ft popping the clutch at 6200rpm/ anti lag. I have broken 2 but Im sure it was wheel hop since my subframe is stock. And no way you'll gain 10mph going down to a 3.69 if anything you'll lose mph cuz you'll be in gear longer, finishing in top of 3rd. Btw the z32 diff is 4.08 not 4.11 unless you changed the gears
RosadoRacing
Dont Question My Nissan Knowledge
Posts: 541
Joined: Tue Apr 06, 2010 5:33 pm
Location: Bethlehem, PA

Re: diff quart mile question?

Post by RosadoRacing »

This is somewhat off topic but who ever tells you a quicker 60ft will lower your trap speed is wrong.
Badazzsr20
240sx Wannabe
Posts: 140
Joined: Wed Sep 09, 2009 8:35 pm

Re: diff quart mile question?

Post by Badazzsr20 »

what kinda horse power u droping that clutch at 6200 with j30 axles? i hear that j30 axles are only good for 500 max. i guess ill leave the z32 diff in for now and i thought i have read the z32 is 4.11gears. once i get more power ill have to look into the 3.69 gear i guess.
RosadoRacing
Dont Question My Nissan Knowledge
Posts: 541
Joined: Tue Apr 06, 2010 5:33 pm
Location: Bethlehem, PA

Re: diff quart mile question?

Post by RosadoRacing »

Going with the 3.69 isn't going to make your rear end stronger because they use 29 spline axles which are the same ones you have now. pre 95 q45 are 3.54 and they use the bigger axles but good look finding a z32 turbo axle. I'm only launching on 6lbs idk how much hp maybe 250.
Badazzsr20
240sx Wannabe
Posts: 140
Joined: Wed Sep 09, 2009 8:35 pm

Re: diff quart mile question?

Post by Badazzsr20 »

The Q45 are to he strongest diff out there from what I have read/heard. How are all these guys with s14 running. 7s and 8s from what I understand it's q45 and axles and 1 300z TT axles. After that do what u want to the car u won't brake it.
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