Best gearbox/diff set up for 4.5 S6 engine

[rcvaughan]

My T350 will likely become a 4.5 supersports engined car very soon and, whilst the engine is out I thought I'd do a few other things.

So, what is the best gearbox and diff setup for the 4.5 engine if I'm looking for acceleration rather than top end? First hand experience preferable but general knowledge on the subject would be appreciated.

What other little jobs should I do whilst the engine and box are out? I already have lightened fly and uprated clutch on the list.

Thanks

[RedSpike66]

I'd ask Dom - he has been driving his for a year or two now...

[Templedog]

As the man says, talk to Dom. I was advised not to go lightweight flywheel as it means less torque. Upgrade the suspension and start saving for sticky tyres. If you're coming from a standard 3.6 take it very steady when you first get it back. The power delivery is completely (surprisingly) different. You have loads more torque so take into account you have to get this down on the road when you choose your gearing diff etc.

[Tuscanuwe]

Traction will be the challenge, i have a 4.3 and in 1st or 2nd its
nearly impossible to accelerate without wheelspin if you put the pedal to the metal.
A longer diff would be helpful i think and stiky tires.

And a full fuel tank, to get weight on the rear axle!

Uwe

[Getsis]

I'm happy with the std g'box and diff set-up in my 4.5. I will only think about other options when they need replacing. A sixth gear would be nice just to make things quieter on long motorway journeys. I would like to hear the radio sometimes.

[Tuscanuwe]

I would like to hear the radio sometimes.

---

You have chossed the wrong car for radio listening!!!!!!!!!!!!


Uwe

[Brummmie]

3.45 i reckon, i have same ratios in the gearbox in my TKO as a T56, but i have a 3.08 with around 600lbs/ft of torque. you may even pull the 3.23??

[rcvaughan]

thank you for the replies

silly question perhaps but the lower the number the better the acceleration? and reduced top end i guess

[Tuscanuwe]

but the lower the number the better the acceleration

---

But the challenge is to get the power on the road
---Or: how to prevent the wheelspin!-----


Uwe

[Grey Ghost]

This thread might be a good read for you

http://www.pistonheads.co.uk/gassing/topic.asp?h=0...

[YRRunner]

rcvaughan said:

thank you for the replies

silly question perhaps but the lower the number the better the acceleration? and reduced top end i guess

Other way around I think. Higher the 3:?? the better acceleration, but loss in top speed. My 3:91 with CR box (in a standard 4.0) has a much longer 1st than the standard 3:46, 2nd and 3rd are reaaaaallllly long and pull hard. Fewer gear changes and blistering off the line compared to the 3:46. That's my experience of it anyway, but many will argue as in previous threads. All I know is that the difference promised by John Reid turned out to be on the money. I did it because I wanted better lift off more than top end max speed. Works for me, although with an imminent 4.5 upgrade, I will be looking to go back down the numbers I think.

[SAGRIFF]

best go for a 3.9/3.7 if you can't press the throttle pedal all the way down

[jcpgasoline]

YRRunner said:

rcvaughan said:

thank you for the replies

silly question perhaps but the lower the number the better the acceleration? and reduced top end i guess

Other way around I think. Higher the 3:?? the better acceleration, but loss in top speed. My 3:91 with CR box (in a standard 4.0) has a much longer 1st than the standard 3:46, 2nd and 3rd are reaaaaallllly long and pull hard. Fewer gear changes and blistering off the line compared to the 3:46. That's my experience of it anyway, but many will argue as in previous threads. All I know is that the difference promised by John Reid turned out to be on the money. I did it because I wanted better lift off more than top end max speed. Works for me, although with an imminent 4.5 upgrade, I will be looking to go back down the numbers I think.

That's right. The numbers 3.91, 3.73 & 3.46 are the numbers of revolutions the drive shaft makes per revolution of the wheels. The higher the number, the lower the final drive ratio.

[D14 AYS]

I am taking a 3.7 out of my Sag, next week, I kept my 3.4 just incase! With the 4.5 the 3.7 is to much, so a nearly new 3.7 diff 2k miles will be in the classifieds soon.

[jcpgasoline]

D14 AYS said:

I am taking a 3.7 out of my Sag, next week, I kept my 3.4 just incase! With the 4.5 the 3.7 is to much, so a nearly new 3.7 diff 2k miles will be in the classifieds soon.

So you'll be running the 3.46 diff with the CR box? Or standard box?

[jcpgasoline]

Reason I ask is that I now have a TVR Power 4.5 in my Tuscan S...

[D14 AYS]

I think it's a standard box, but I will find out.

[Robertjp]

jcpgasoline said:

Reason I ask is that I now have a TVR Power 4.5 in my Tuscan S...

Congratulations!! Much difference from your original 's' engine??

[jcpgasoline]

Robertjp said:

jcpgasoline said:

Reason I ask is that I now have a TVR Power 4.5 in my Tuscan S...

Congratulations!! Much difference from your original 's' engine??

Thanks! The engines really are chalk & cheese, and I haven't even had the final mapping done yet as I'm still running her in.

The most obvious difference to me is the increased torque and it's "on-tap" availability. It runs very smoothly and pulls really well from low revs, so it's quite happy tootling along at 2000 rpm and then you can simply put your foot down and unleash hell! Mid-range acceleration is astounding and I have haven't really explored the top end properly yet...

Having said that, all that power demands respect and I can see why some of the other 4.5 guys are going for a higher final drive with so much torque on tap. I have R888's on my car so that's probably helping a lot, but even so it is REALLY easy to spin the wheels in 1st & 2nd.

I'm looking forward to taking the car back up to Dom for the final remap (about 1500 miles to go) when we should get some pretty impressive power & torque stats thanks to the Tuscan S exhaust which is more free flowing than the Sagaris's.

In the meantime, I'm looking forward to a good long drive this weekend.

[jcpgasoline]

D14 AYS said:

I think it's a standard box, but I will find out.

Did you find out if it's a standard box or not?