I've had a set of 4.56r gears in my final drive for 5-6 years now, unfortunately i 'think' the diff is on its way however i dont think the ring and pinion is damaged which is what you get in a final drive set - my friend reckons its not the noise he would associate with damaged teeth so the ring and pinion will likely be fine.

The final drive wasn't cheap and it would be a shame to get rid of it and it helped a lot NA, however i think because the car sits 300-500rpm higher in each gear and you have to change more often its actually limiting the performance of my car since its boosted its an AP1 (CTSC+AC@10psi with bolt ons) and circa 330BHP/210 lb-ft torque @ the wheels and believe the spread of torque is affected so other than standing start low gear situations its decremental for my performance.

I think i'd prefer better performance from a roll/dig rather than standing starts/very very low speeds.

What do you folks think? can you explain?

I'm not into standing starts, 1/4 miles so perhaps going back to 4.10 would be better on the road and from a shift down when wanting to go 'some'.

I may try and salvage the final drive or just replace it.

I've now embargoed the car whilst i decide what I'm going to do.

 

IMHO....

If you plan on staying at or below the 330-HP mark, I would keep the 4.56's providing they are still in good shape. I had a set of 4.57's for years when I had my CTSC setup (315-HP)....and I think that the gears were one of my favorite & most useful mods, and deifitely made the car a lot more fun to drive around town.

When I changed from the CTSC...to the Turbo, and added +215-HP, I went back to the 4.10's

Goodluck

 

Sure are more fun, but i just want to know if the car will be faster from a dig and in gear without the 4.56r's.

Thanks

 

From a roll the gears will be hurting you I'm pretty sure. Even NA with the 4.77's they really felt like they were hurting my acceleration.

With boost especially 10+ psi they will hurt you.

I'd ditch them and get some stock gears back in there.

 

Yup thats what i was thinking

 

Keep stock gears unless your motor is bone stock. Anything over 20whp gains and I start thinking that shorter gearing is a mistake. Hell I'd prefer taller gearing in my turbo car, I can spin most anywhere in 1st or 2nd gear, why go taller? So I have to shift more and then can't get past 155mph? No thanks.

-Greg

 

I can't imagine boost with shorter gears, especially on an ap2. If anything I'd want a taller FD in my ap2 if I had boost.

 

Agree

 

Go back to 4.10 AJ. You know that's my consensus after we spoke.

 

Gone back to 4.10 over the weekend it feels slower for sure low down.