Rally car at auction

[Alphabettispaghetti]

Ok so 70mph will be nearly 4000 rpm. When you are driving your modern car have a look at the rev counter when you are doing 70. Then change down until it reads nearly 4000 and keep it at that for a while.

My Sam has a 3.7 and it's fine.

Rob, in a 3.9 you're only 500rpm lower...... Its not a modern car.

On the flip side my modern car won't rev to 7500odd rpm, it will do upto 80mph without any revs.

3.7 is a very low ratio, useful for trips to the south of France though, seems an odd choice, quite a bit more touring than sport?


To be clear, 4.44 ratio diff 70mph is 3696.2839rpm.
3.9 3246.73 rpm
3.7 3080.23 rpm

I'm not sure what it is you worry about with a 4.44?

Thats all based on 205/60/14.

 

[SeanDezart]

Rob, in a 3.9 you're only 500rpm lower...... Its not a modern car.

On the flip side my modern car won't rev to 7500odd rpm, it will do upto 80mph without any revs.

3.7 is a very low ratio, useful for trips to the south of France though, seems an odd choice, quite a bit more touring than sport?


To be clear, 4.44 ratio diff 70mph is 3696.2839rpm.
3.9 3246.73 rpm
3.7 3080.23 rpm

I'm not sure what it is you worry about with a 4.44?

Thats all based on 205/60/14.

My god, you'll despise me then 3.54, 225/50x15s equates to 3000 ? rpm at 70 ?

But the thing is old chap, we're allowed legally to drive at 80mph which I'm hoping'll be 3400rpm which is pretty handy considering that our country can't be crossed in a mere 3hrs !

If I want to do 'sporting', there are still 4 gears to play with.

 

[Alphabettispaghetti]

I don’t dispise at all, rob just needs to understand/see that it’s no way near the impact he thinks it is. Not to mention the extra shove from a proper ratio, just a fun feeling car.

 

[johnymd]

I do a fare bit of mileage in various zeds and I think its down to horses for courses. When I'm traveling any sort of distance I tend to use the motorways rather than B roads so would like the car to cruse comfortably at 75-80mph so I can keep up with other traffic. My silver car with a UK 5 speed 280zx box and 3.9 diff will rev at around 3200 with the current tyres. If I put the red ones back on then the revs will go up a couple of hundred. Once you get up to 4k the cars become a bit of a pain both on noise and fuel consumption IMO. On the other hand, if you just want a weekend warrior for the B roads or track days then you want all the acceleration you can get so your not worried about motorway driving.

At the end of the day there is no right or wrong as we all build cars that are right for us and us alone.

 

[Albrecht]

Single best bang-for-buck fun factor adder for an otherwise standard car: Change the diff ratio to a higher numerical, lower gear. If you can add an LSD at the same time then all well and good.

On my old everyday-driver UK market 240Z (dearly departed) I was running 4.375, 4.6 and - for a short while - 4.875 ratio plate LSD-equipped diffs. The 4.6 and 4.875 were an absolute HOOT, completely transforming the nature of the car. The lower gearing has the effect of closing up the ratios in the transmission, making it easier to stay in the engine's power band for sporty driving. 4.375 was a good compromise, and I could live with it every day no problem. My project 432-R replica has a 4.44 ratio R192 4-pinion diff with plate LSD, same ratio as the OEM R192 on the 432 and 432-R.

I supplied the plate LSD 4.375 ratio R200 diff in the ex-Hugh Myers car, and Tim Riley fitted it.

 

[Rob Gaskin]

....3.7 is a very low ratio, ....., seems an odd choice, quite a bit more touring than sport?....

......If I want to do 'sporting', there are still 4 gears to play with.

...... rob just needs to understand/see that it’s no way near the impact he thinks it is......

My old car with a 3.9 won the speed trial in Malta called the Mdina GP and also competed in the Historic Monte twice i.e. short and very long distance events without gearing issues.

My Sam gearing of 3.7 was not an 'odd choice' made by Jonathan or me it's the gearing that Datsun provided. I think you would be surprised at how sporty that car drives but also how relaxed it can be in top gear. As Sean says we can change down to rev the engine but you can't change up to 6th to slow it down. Also we can use smaller tyres. Your 4.44 is the 'odd choice' for a road car and I suspect was a matter of supply (Subaru) rather than demand. Have you worked out your revs in 1st and 2nd gear yet?

And finally 'Rob just needs to understand' - Franky have you ever driven an S30 or been a passenger in one? If so did it feel over-geared and what was the diff ratio?

I have been driving sporty 240Zs since 1996 (21 years) including trackdays for ten years and driven to Le Mans and Spa, plus a camping trip to Ben Nevis. I know from all that experience how these cars feel (on various sizes of wheel/tyre too).

Anyway this is hypothetical - get your car on the road and then we will be in a better position to compare and discuss.

I know that Alan Thomas likes low geared cars and I also know that Matt 'racer' finds his car low geared for the road. Anybody else used a high-ratio (4.1+) diff on the road?

Franky we'll call it a day now all I was originally saying was that the 'Stage Rally' car is low geared and for someone doing regularity rallies they may need to revert to the standard ratio of 3.9.

 

[Rob Gaskin]

Single best bang-for-buck fun factor adder for an otherwise standard car: Change the diff ratio to a higher numerical, lower gear. If you can add an LSD at the same time then all well and good.

On my old everyday-driver UK market 240Z (dearly departed) I was running 4.375, 4.6 and - for a short while - 4.875 ratio plate LSD-equipped diffs. The 4.6 and 4.875 were an absolute HOOT, completely transforming the nature of the car. The lower gearing has the effect of closing up the ratios in the transmission, making it easier to stay in the engine's power band for sporty driving. 4.375 was a good compromise, and I could live with it every day no problem. My project 432-R replica has a 4.44 ratio R192 4-pinion diff with plate LSD, same ratio as the OEM R192 on the 432 and 432-R.

I supplied the plate LSD 4.375 ratio R200 diff in the ex-Hugh Myers car, and Tim Riley fitted it.

I took a long time to 'type' my reply and you beat it, however I did mention you because you have commented before. It sounds like basically you were driving it as if you stole it which is the only way with a 4.4 I would imagine. I have driven a rally car (Escort) which was low geared and it gets you like that but ......

 

[Alphabettispaghetti]

My old car with a 3.9 won the speed trial in Malta called the Mdina GP and also competed in the Historic Monte twice i.e. short and very long distance events without gearing issues.

My Sam gearing of 3.7 was not an 'odd choice' made by Jonathan or me it's the gearing that Datsun provided. I think you would be surprised at how sporty that car drives but also how relaxed it can be in top gear. As Sean says we can change down to rev the engine but you can't change up to 6th to slow it down. Also we can use smaller tyres. Your 4.44 is the 'odd choice' for a road car and I suspect was a matter of supply (Subaru) rather than demand. Have you worked out your revs in 1st and 2nd gear yet?

And finally 'Rob just needs to understand' - Franky have you ever driven an S30 or been a passenger in one? If so did it feel over-geared and what was the diff ratio?

I have been driving sporty 240Zs since 1996 (21 years) including trackdays for ten years and driven to Le Mans and Spa, plus a camping trip to Ben Nevis. I know from all that experience how these cars feel (on various sizes of wheel/tyre too).

Anyway this is hypothetical - get your car on the road and then we will be in a better position to compare and discuss.

I know that Alan Thomas likes low geared cars and I also know that Matt 'racer' finds his car low geared for the road. Anybody else used a high-ratio (4.1+) diff on the road?

Franky we'll call it a day now all I was originally saying was that the 'Stage Rally' car is low geared and for someone doing regularity rallies they may need to revert to the standard ratio of 3.9.

It wasn’t a matter of supply, it was a decision made once plotting out gears and rpm. If I remember off hand it’s geared for 135mph? As supposed to 160+.

It’s a fully useable set of gears that the bottom 3-4 can be fully used.

I would like a 4.11 also though.

Of course I’ve driven s30’s and been passengers in them, it’s be pretty stupid to commit so much time to something I’ve never driven, wouldnt you agree?

It frustrates me more than anyone that I’m short on time, however it’s allowed me to package the car to my perfect spec.

None of it is hypothetical, it’s just maths. My car on the road won’t be any different to the numbers above. It should be correct within 100rpm.

I only mentioned it as you said my car would be revving it’s nuts off, which I’ve just shown that it won’t, far from it. It’s mis information to say so.

Had your car had a higher or lower ratio it still would have won with the driver.

 

[Albrecht]

It sounds like basically you were driving it as if you stole it which is the only way with a 4.4 I would imagine.

...when I wanted to, yes. But the main point is that it didn't make the car any kind of white elephant. In 95% of driving situations it was improved as a sporting car but I could still bimble around when I wanted to, and spent some time on fast dual carriageways and M-ways. I had - still have - no need of a theoretical top speed of 150mph + in these cars.

Driving character. You can build your car to suit. The one I still can't get my head around is the stock 3.36:1 ratio (with a 1:1 top gear 4-speed!) of the North American market cars. It has the effect of widening the drop-off between gears and the effect is rather like driving a big saloon car from the 1960s.

Tyre size is a big factor in all of this of course. As a reference the Works rally cars usually ran on 4.875 and 5.1 ratio diffs, but usually with a large tyre diameter (well over 730mm).

 

[jonbills]

fwiw, I recently switched back from a 3.36 to a 3.7. It really doesn't make much difference on the road.
I think I preferred the 3.36 at Santa Pod, since that keeps my peak RPM in 3rd around 8k ish. I think the 3.7 is a bit scary with revs maybe going up to 8500.

 

[Alphabettispaghetti]

fwiw, I recently switched back from a 3.36 to a 3.7. It really doesn't make much difference on the road.
I think I preferred the 3.36 at Santa Pod, since that keeps my peak RPM in 3rd around 8k ish. I think the 3.7 is a bit scary with revs maybe going up to 8500.

That’s the exact point, you’re only taking 500rpm, not 1500.

 

[Albrecht]

I think I preferred the 3.36 at Santa Pod...

You'd probably prefer a Torqueflite at Santa Pod.

 

[Nigel Brook]

diffs

I know someone on here (forest racer) who is running a 5:1, if he's put it in yet. Be interested to know how he's getting on with it.

 

[jonbills]

You'd probably prefer a Torqueflite at Santa Pod.

I'm beginning to think I'd prefer to be using someone else's car at Santa Pod!

 

[SeanDezart]

I ran my yellow Z on an R200 3.7 LSD and it was plenty quick and nippy enough and usefull for holding in third down the country roads.
I have gone for an R180 3.54 Subaru LSD and will see how that feels - it might be in keeping with my desire to be more of a sports GT than an out and out sportscar.
If I don't like it, I have others on the shelf of various rations both LSD and not - I'll change.

Alan - the 3.36 and 4spd - I've driven quite a few now is merely 3 decent gears and an overdrive and (ducks for cover) the 5spd is merely 1x gear more and an overdrive.

But agreed with you that changing the ratio from 3.? to 4.? will close up the gears....it's just that perhaps you've not driven regularly anything bigger than a an L24 with a mild cam and triples and those you have have need high revs to get the best out of them ?

 

[Albrecht]

Alan - the 3.36 and 4spd - I've driven quite a few now is merely 3 decent gears and an overdrive and (ducks for cover) the 5spd is merely 1x gear more and an overdrive.

I think calling the 1:1 top gear in the 4-speed 'boxes an "overdrive" might raise a few eyebrows.

But agreed with you that changing the ratio from 3.? to 4.? will close up the gears....it's just that perhaps you've not driven regularly anything bigger than a an L24 with a mild cam and triples and those you have have need high revs to get the best out of them ?

I've driven plenty of big-engined, big-powered L-gata engined S30s in Japan over the years. A few here too. I think I know what I'm talking about. If you've got the power to pull a 3.7 or 3.9 properly then all well and good, and many of the big-turboed cars like to push against a tall diff ratio and wide gear spacing (one of the outright fastest street cars I've ever been in was a Z31 which was running over 700ps and used a 3.1 diff ratio...), but we are not really talking about BIG power cars here.

Ideally you'd be planning your diff and gearbox ratios to suit tyre diameter against likely top speed needed. Easy on a track, and - theoretically at least - even easier for the road (because of national speed limits...) but you set the car up the way you want.
As Franky has been trying to get across, 4.375 and 4.44 diff gearing is just not that radical in the grand scheme of things with the size of tyre that he (and I) intend to use.

With a normally-aspirated engine, the way you go faster is - basically - to turn more revs.

 

[SeanDezart]

With a normally-aspirated engine, the way you go faster is - basically - to turn more revs.

Tell that to cyclists....pedal faster yes, but if you want to go faster, you 'up' a gear !

Agreed, one has to match the tyre/wheel size, diff ratio, gearbox ratios and engine characteristics.....for the use one expects and let's face it, for 90% of us here that's going to be on the public road for 95% of the time.

I'd rather be on my roads here than yours there in any Z !

 

[Albrecht]

Tell that to cyclists....pedal faster yes, but if you want to go faster, you 'up' a gear !

By all means try a 3.1 and tell me how you get on.

 

[SeanDezart]

By all means try a 3.1 and tell me how you get on.

Tried a 3.2 in a BMW M3 coupé - not bad but I'll stick with my 3.54 - good enough for Scooby STis which're no slouches, good enough for me.

 

[Alphabettispaghetti]

Tried a 3.2 in a BMW M3 coupé - not bad but I'll stick with my 3.54 - good enough for Scooby STis which're no slouches, good enough for me.

Totally different gearbox ratios though.

A big part is matching it to the engine, I’m staying very modest power wise, just s warmed through l24, one that is happy to Rev a little.

I’ll leave massive torque for the tdi motorway car.