Rpm At 100 Kph

[jrh001]

I know there are lots of variables but was just wondering what other older Nissans/Datsuns show on the tacho at 100kph.

My result is:

Skyline MR30, L24E, 3 speed auto (!), 83 series 1, 3500 RPM

Not so good on economy but hums along nicely on a good day.

cheers,

JH

[Ghostrider]

I know there are lots of variables but was just wondering what other older Nissans/Datsuns show on the tacho at 100kph.

My result is:

Skyline MR30, L24E, 3 speed auto (!), 83 series 1, 3500 RPM

Not so good on economy but hums along nicely on a good day.

cheers,

JH

Hi John,

Your problem is the 3 speed transmission because top gear is 1:1 and not overdrive as in the later model 4 speed.

Have a play with this link and you will see what you have got.

http://www.testarossa.jp/utility/gear.html

Your gear ratios are: 1st: 2.458, 2nd: 1.458, 3rd: 1.000 and at the bottom after 6 is diff ratio: 3.9

Cheers, D

[Ghostrider]

The testarossa link will give you 106kph @ 3500 & 91 @ 3000 in top gear.

[jrh001]

Thanks Dennis,

Looks like I'm 'spot on' then. Not so bad for a car with 260,000km on the clock.

I'll be interested to see some real-life figures from a 4 sp auto and 5 sp manual. (Maybe you can take the PNV for a run.)

cheers,

JohnH

[Ghostrider]

Just by using the Testarossa link and the right gear ratios the 4 speed auto has 0.686 overdrive and does 111kph @ 2500

The 5 speed MR30 with 3.9 diff & 0.833 od it does 92kph @ 2500 and 110kph @ 3000 in top gear.

The PNV however has an od of 0.813 just a tad higher, but with lower diff ratio of 4.11 and it does 89kph @ 2500 and 107kph @ 3000.

As a result of this, my modified L20et (umm 2818 L20et) PNV will have an 3.7:1 diff with a modified R32 GTSt gearbox with an 0.759 overdrive so that it will be a much better cruiser just chugging along on 106kph @ 2500 rpm off boost.

Cheers, D

[Socrates]

Skyline C210, L24S, 5 speed Manual), 78 series 1, 2800 RPM

[66yostagea]

The 686 drive of the auto 84 model I had gave just on 100 at 2000 + a bit. Also it was very economical.

[noddle]

73' 240K, L24, 5 Speed, 2800 RPM @ 100k, my manual say 3.545:1 diff ratio

Edited March 3, 2011 by noddle

[Ghostrider]

The most crytical part of kph @ rpm is your tyre size. Just changing from factory fitted 195/60 x 15 on an R30 to 205/60 x 15 which is the common & norm here in oz, it makes an incredible amount of diferrence to the end result.

D

[NightMonkeyII]

speedo doesnt work. have new speedo cable, just have to put it in.

When i sit with traffic on camden bypass at 100km/h, im doing 4000rpm!

so i sit on 3500rpm for economy's sake, and everyone is overtaking me

Took the air filter element out, held engine speed at about 3000rpm, spayed throttle body cleaner

up the air flow meter for about 30 seconds. No difference performance wise, but uses a lot less fuel and a bit smoother

(not that it wasnt smooth before)

[jrh001]

The 686 drive of the auto 84 model I had gave just on 100 at 2000 + a bit. Also it was very economical.

What is a 686 drive?

JH

[Ghostrider]

What is a 686 drive?

JH

Overdrive (4th) gear ratio of 0.686:1 in later model RMR30's

D

[samkhan86]

Its JAPANESE but its discernible through context..however i cannot find the ratio specs for the r30 4sp auto gearbox. Who has?

Thanks in advance.

EDIT:

I punched in 0.686 ratio for gear 4 with a diff of 3.9 - gave me 96k/h @ 2000 rpm and 121 k/h @ 2500 rpm - ABOUT RIGHT! guess she pulls her weight alrigght, considering she's done 140k since 1984.

Edited March 4, 2011 by samkhan86

[Factory 5]

The tyre sizes make a huge difference.

I had low profile 15" and acceleration was great, but revved alot on the highway. Then I had stupid high profile things, like of a falcon. Well it was doing about 190 at 6000rpm... apparently...

[Ghostrider]

Its JAPANESE but its discernible through context..however i cannot find the ratio specs for the r30 4sp auto gearbox. Who has?

Thanks in advance.

EDIT:

I punched in 0.686 ratio for gear 4 with a diff of 3.9 - gave me 96k/h @ 2000 rpm and 121 k/h @ 2500 rpm - ABOUT RIGHT! guess she pulls her weight alrigght, considering she's done 140k since 1984.

4 speed auto >>> 1st: 2.842, 2nd: 1.542, 3rd: 1.000 & 4th: 0.686. Reverse: 2.400 Diff: 3.9

Cheers, D

[noddle]

I noticed no one is putting down what there miles per gallon is, since this is where the saving is,

I'm running a L24 inter-cooled Turbo, running EDIS ignition (waste spark), Megasquirt II using the version 3.0 board, running the latest MS Extra firmware,

3 inch mandrel bend exhaust, with a free flowing muffler, and 7 PSI for normal driving, switchable to 10, and 15 PSI

I just came back from a trip, 290ish kilometers, I sat on between 105-115k's 80% of the way,

and I'm getting 34.34 miles per gallon, or 8.22 liters per 100k's.

I'm very happy with this, good fuel economy, and plenty of power, when I put the foot down a little.

to get it running this good, I run it lean (2500 - 3600 RPM), AFR sits between 15 and 16.5 (light cruise), EGT sits about 770ish just before the turbo.

Nigel

Edited March 6, 2011 by noddle

[Factory 5]

Factory L24e setup I was getting 12lt/100km highway cruising

Microtech fuel only LT-4 and 270cc NEW injectors was getting 8.5lt/100km

[jrh001]

Spec figures from carbuddy.com for L24E:

4sp auto 13.5L/100km city and 8.5L/100km highway.

3sp auto 14L/100km city and 10.5L/100lm highway.

5sp manual 13.5L/100km city and 8.5L/100km highway.

I'd like to try bigger wheels, only running 14's at the moment (195/65HR14). The speedo reading will be out with larger rims/tyres. My guess is that 5% larger outer diameter means 5% lower reading on the speedo - so when it says 95, actual speed is 100.

JH

[Ghostrider]

Spec figures from carbuddy.com for L24E:

4sp auto 13.5L/100km city and 8.5L/100km highway.

3sp auto 14L/100km city and 10.5L/100lm highway.

5sp manual 13.5L/100km city and 8.5L/100km highway.

I'd like to try bigger wheels, only running 14's at the moment (195/65HR14). The speedo reading will be out with larger rims/tyres. My guess is that 5% larger outer diameter means 5% lower reading on the speedo - so when it says 95, actual speed is 100.

JH

Ummmm now we are talking tire sizes, well factory fitted 14" tires were 185/70 x 14 & 195/70 x 14 or Ti 195/60 x 15.

185/70 x 14 have a dynamic radius of 299mm

195/70 x 14 have a dynamic radius of 306mm

195/60 x 15 have a dynamic radius of 297mm & optional fit 205/60 x 15 is 303mm

And it's the dynamic radius that counts when it affects the speedo numbers.

And John, your 195/65 x 14 is 295mm

(figures compliments of http://www.toyo.com.au/Tyres.htm)

Cheers, D

[jrh001]

Ummmm now we are talking tire sizes...

Yes, we're wandering off the topic slightly but it's all related. Thanks for the tyre figures. I found this tyre calculator on a VW site: http://www.club80-90...0calculator.htm

I'll check my fuel economy and post some figures as well.

Meanwhile, it might be interesting to see some figures from even-earlier Skylines. The figures from '73 to '83 are all very similar.

cheers,

JH