Paxton and gearing comments wanted

[Viper IV]

I'm looking for gearing comments on what is working out best for fellow members with a Paxton installed for straight line tracking.
I'm going to Quafie and have two SRT-10 rear end assemblies. I just don't want to spend the money for both 3:07 and 3:55's. I'm going with 18's in the rear.
Which one is working out best or are you sorry you changed after doing one over the other with the paxton ?

Regards
Rob

 

[Paul Hawker]

Mixed emotions. I have Paxton with 3:55's. For street cruising it is fantastic. Always just a heartbeat away from gut wrenching accelleration, however I believe that the 3:07 would be faster. You hit the rev limiter in a flash with the 3:55. The 3:07 would allow the motor to pull much longer between shifts.

 

[edretti]

333's seem to be just great to me.

 

[Viper IV]

Paul, I'm tending to feel the same way. I have 3:55's in there now and 1st gear seems useless right to the rev limiter in a second. I want to quafie due to the power and I expect the rear to break sooner or later.
If anyone has a supercharged SRT with 3:07's I would appreaciate any input you may have. Once I'm quafie'd my mind will be at ease and I'll probably sell off the spare rear end unit.
Thanks
Rob

 

[GR8_ASP]

I think 1st is a flash and into the rev limiter bo matter what the gear ratio. The tires just do not have enough grip.

 

[ViperGMC]

I asked this question several times after I installed my SC. I felt the 3.55 too much so I never changed the rear gear. I chose to keep the 3.07 when I installed the Quaife as well. Traction has always been an issue with the SC, but I have gotten much better at handling the car (after many hours at the track) to where the traction is not so much an issue anymore. I think the 3.55 is a great combo for a non SC car. I can usually spot the 3.55 cars at the track by the way pull out of the corners.

 

[SnakeEye]

... I'm going with 18's in the rear. Rob

3.33's with 18's
3.55's with 19's

Good luck.

 

[slither]

Totally agree with SnakeEye. If you're running 3.55's with 18's on the back (26.1" diameter) and you switch to 19's on the back (27.4" diameter) you now have the equivalent of 3.38's in your car. I have an '04 (19's with stock runflats, 27.4" diameter) with a Paxton and put 3.45's in the rear, to me its perfect. If I switched to 18's it would be equivalent to having 3.62's in the rear which would probably be too steep. Simple math.

 

[Nader]

What if you were going to do 20's in the rear?

 

[slither]

Aahhh dubs, very nice - ha ha. Well a Pirelli P-Zero Rosso in a 345/25-20 has an OAD of 26.8" which is right in between a 335/30-18 (26.1") and a 345/30-19 (27.4"). I'd go with either a 3.33 or 3.45. The tire size itself is not the governing factor, its the diameter. You would think 20's would have a larger OAD than 19's, 19's than 18's, etc.. but it depends on the aspect ratio (the 25, 30, 35 etc.. in the tire size). If you go with a different sized 20" tire you need to find out the OAD of that particular tire and select gearing based on that, though 3.33 to 3.45 isn't much of a difference.

 

[Bill Pemberton Woodhouse]

We have installed a slew of the Paxton's and though it would be beneficial to us to suggest a gear change, we strongly believe it is best to stay with the 3.07s. As noted by a few, it is a quick rush to shift and it just gets there too mega quick with the 3.55s.

Bill Pemberton
Woodhouse

 

[JB/SRT]

Let me offer my new perspective about 3.55s.

Four weeks ago I had the Paxton, Quaife, 3.55s, and rollbar installed. Around town and on the road I really like the 3.55 over the 3.07s. Now all 6 gears are usable routinely, while with the 3.07, around town it was basically a 4 speed. Some may not like the extra shifting, but I love it.

The top of first does come quickly, but it doesn't bother me to shift 1-2 seconds earlier. Line up a 3.07 next to 3.55 and which would have a better 60 ft? As far as traction, I have noticed that the Quaife has really improved traction even with the Paxton. It seems much easier to stay just below the tire spin threshold with the Quaife even with the extra power, and when the tires do break, tracking is straight and spin is minimal before recapturing traction. One thing I don't know yet is whether I can trap the 1/4 in 4th before having to shift.