Hi All

I know this is a drivetrain question but I figured I would only find others who have done what I have after going FI.

I'm hoping to get some feedback from others who have boosted their power and decided to move down to the 3.3 rear end.

I'm making about 500ft/lbs with a TT setup and I am about to upgrade to Quaife diff. I've considered it for a while and want to hear what others have to say.

The plan is to autoX occasionally. I know going from the 3.5 to 3.3 would take a little torque away but being able to stay in gear slightly longer/have slight higher speed seems like a nice trade off to me.

Thanks for your time!

 

I see you're not getting any answer here- someone asked a similar question over in my350z and I'm not sure if it's you but everything I've ever heard since I got into the game was that it's one of the best mods the guys with high power can do in terms of keeping some tread left on the tire.

In essence- there's no sense having TQ if you can't put it into the ground in the form of accelleration as opposed to just a billowing cloud of rubber and smoke particles. The 3.3 brings function back to your first 2 gears where my understanding is your 3.5s can lead to a bit of a rodeo.

Guys in the AT NA word like the 3.5 because it does tighten things up and make their starts / launches quicker- so what I'm told frequently happens is the NA AT guys swap their 3.3s for the MT 3.5s straight across.

Especially with a TT setup that "loss" of TQ may not even be noticeable.

If I were in your position (I'm ALREADY a 3.3 because I'm AT)- from what I've learned I would DEFINITELY move to a 3.3- hoping to trade straight across with an NA platform.

 

I know that TTRANK did the 3.5 to the 3.3 swap. He is TT pushing 580/580 on pump and 650/650 ish on race gas IIRC.

Pumpkins are easily swappable. Consider installing a true LSD instead of just looking for the 3.3 VLSD if you can. Especially if you plan to Auto X

 

Thanks for the responses guys.

 

I went from the 3.5 to a 3.3 with a Quaife, it helped the traction alot. The genral rule of thumb is over 550ftlbs you will like it, under keep the 3.5FD.

With 500ftlbs You could likely be happy with the 3.3

 

Do you think the 3.5 would have been decent with an LSD? Curious because I'm currently going from a 3.7 to a 3.5 w/Quaife.

 

[QUOTE=dougk12;6458984]Hi All

I know this is a drivetrain question but I figured I would only find others who have done what I have after going FI.

I'm hoping to get some feedback from others who have boosted their power and decided to move down to the 3.3 rear end.

my std rear tires are 245-45-18 by going up one size to 255 you pick up 10mm=.400 incr in dia plus a little width for better traction, this equates out to about 1.5% in gearing, might be good for you considering all that torque

 

Yes it would be fine, I only recommend the 3.3 if you are over 550wheel torque other wise stick to a 3.5. The quafie is a great all around diff you will like it.


And yes tire size can act the same as changing the gearing, but it will also mess up your VDC if your ratios get to far out. A 255mm rear tire on a boosted car would be terrible 275/285 are the smallest tires that give reasonable traction when boosted.

 

+1

if you are boosted i would expect no less than 275 on the rear tires.