wanklin

iTrader: (2)

I would like to know how others feel about the 4.77 final drive ring and pinion setup. I am considering changing to 4.77 in order to maximise pre-boost torque.

Do the gears become annoyingly short for street driving?
How noticable is the increase in torque and preboost acceleration?
What is the top speed of the car reduced to?

Please keep replies factual and germane.
thanks

XSTransAm

with the 4.77 you go through the first and second gear too quick to build any good amount of boost. IMHO

wanklin

iTrader: (2)

Have you actually driven a 4.77'd FD? Generally speaking, how much of a difference in time is there between shifts as compared to a stock geared FD?
Are the shifts annoyingly quick?
Do you feel like you run out of gear in 5th?

note that this is for a 500+ RWHP single turo, semi bridge ported setup. Boost is kicking in around 4500RPM.

Wargasm

With a 4.77, the gear-limited top speed will be reduced to around 172 mph if you run stock diameter tires.

That's not a problem (on the street anyhow)... the problem is going to be that with 500 rwhp, you will not be able to use first or second at full throttle IMO.

My 400+ rwhp FD on stock-sized R compound tires will light up all of first, all of second, and sometimes part of third gear and that's with the stock 4.1 ring/pinion! True, I need to fit larger tires, but I think you see where I'm going. Having a buttload of power isn't squat unless you can get it to the ground to move the car.

If you plan to _road_race_ the car, and you are going to be going at higher speeds (100 mph+) most of the time, this may not be an issue because you won't spend time in the "grabby" 1st and 2nd gears.

So my advice is to think carefully about what you want the car to do well. Drag? Road race? AutoX? Street machine/all around? The only situation I can think of right now where a 4.77 might make sense on a car with that much rwhp is on a road race car.... maybe...

Brian

wanklin

iTrader: (2)

This car's primary purpose is going to be road racing yet it will be a daily driver. But the main motivation behind this is too give the car a little more grunt before boost kicks in. With the port that's in it now it is somewhat of a dog before boost kicks in. I want more usable power so that I have enough preboost available to pass cars on the street while keeping the car under the turbo RPM threshhold. The extra torque will also come in handy when exiting sharp corners on the track.

Wargasm

Hmm a tough spot to be in... if you change the turbo exhaust housing, you get better street spool, but your turbo shaft RPM goes up on the track....

Maybe some gears will help (with big *** tires!)

I dunno...

B

speedypete

I'd go 4.33 maybe. 4.77 will have you dancing around too much rather than concentrating on driving IMHO. That's the problem with really big singles for roadracing. I think Gordon Monson (sp?) runs a single at VIR every now and again. He might be a good source for first hand knowledge.

clayne

Well you'll definitely put more torque to the ground, but at the expense of shifting more often.

If you have no issue with shifting more frequently or modulating throttle (i.e. not full the entire time), it won't be an issue for road racing (seeing as I doubt you're hitting 172 mph on straights).

But it's also track specific - shorter, lower speed, and more turns would most definitely benefit from increased FD ratio. Longer straights, higher speed and longer turns would require you to hold at redline or shift - which as we all know is not the best idea while pulling lateral g's.

If you want more torque for traffic, why not just downshift?

ZoomZoom

iTrader: (2)

I would Def use the 4.77 gears if I swapped to a Aftermarket Transmission. Like a Tremec or a Getdrag 6 speed. Those gear are too tall for a low torque rotary. I would def use the 4.77 in that case. You can always put them in and see how you like them. I mean they arnt welded in! You can swap them back out.

7mania

ZOOM ZOOM;

So do you mean that aftermarket 6 speeds transmission like what you have mention with the 4.77 final gear ratios is a good combo rather than the stock 4.10 that is if you swap to aftermarket tranny. In that regard, what is street drivability, top speed. What do you think will be the best final gear ratios for the HKS 6 speeds gear ratios below. What is the estimated top speeds and speeds through each gear. Ok can you analysize this for me, this is the HKS 6 speeds transmission for the FD3S:

1st gear ratio: 2.773
2nd :1.984
3rd :1.548
4th :1.246
5th :1.000
6th :0.807

wanklin

iTrader: (2)

A lot of pertinent info, thanks.

Down shifting is always an option but practically speaking I am more likely then not to engage boost in doing so.

A 4.33 FD is an option but from what I've read it really makes a barely noticable difference.

I would love to upgrade to a aftermarket 6-speed but my funds have been pretty well tapped for the time being. Maybe in a couple years I will be in a position where I can consider tranny upgrades and traction control. I am in a transitional phase careerwise so I'm going to have to be prudent with my spending on this FD addiction.

The car is not going to be tracked until I am in a position where I can afford buy race tires regularly and repair breakage.

wanklin

iTrader: (2)

I am also considering going in the direction of a T2 LSD to strengthen the rear end, seeing as how my car is just waiting to break the rear with the power that it's making. I've already purchased unobtanium diff bushings and I plan on buying a diff brace and upgraded axles. Where is a t2 LSD going to leave me FD wise? Is it possible to run FD3S ring and pinion with a T2 LSD transplant? I'm assuming that it isn't however I don't claim to be a master mechanic, just an informed consumer. I'm assuming that a T2 LSD is going to leave me needing a custom ring and pinion setup? If that were the case maybe 4.5ish would be better suited for my application.