[Johnb6249]

I drive a 2000 jimny with 13bb engine,50 mm lift super soft springs and run coopers 235/75.15 on 15x7,I've just done a drive down the Hume covering 1050 km in a day,not something I would often but was quite pleasant.My query is at 110 I'm sitting on 3900 rpm,1)would a six speed lower this,2)would a transplant of 16b give me what?? I have found the 13bb to be an outstanding engine and don't want to upset the lite weigh nature of my zook.With the addition of of a rear diff lock I can't see many places this little won't go..thks

[tanshi]

If you lower the revs much more than that your gonna be forever changing gears on hills.

if your happy driving it like that leave it as is.

[sideways]

No 6 speed will fit. G16b conversion will give you exactly the same revs.

Suzukis really need to be pulling those sort of rpms at highway speeds. After all it is a tiny, revvy engine in something about the same size as a SWB 40 series Land Cruiser.

You will never hurt the engine with those sort of revs if that's what you're concerned about.

[AckerDackerly]

This may be hard to believe, but us USAens have discovered that 3600-4000 is a nice place to run the 1.3 (and the 1.6 too).

I have driven the Hypnotoad for hundreds of miles (kilometers x 1.609) at around 100kph on the interstate highway ("M" road?) at 3900 RPM.

Sure, I got the "finger" from passing cars (even though I was in the "slow" lane!) but hey. that's their problem for being in a big hurry...

Start worrying if you push that motor past 4600 for extended periods...

I have had my engine doing that for nigh on to 12 years and it's still running fine.

[sideways]

FWIW the F10a engines in my LJ and Sierra sit on almost 6000rpms at 110 and are happy doing it for hours on end.

[Munster]

My G16B sits on 114kph at 4000rpm.

[Jezza86]

theres correct gearing, and overgearing and undergearing

under gearing means you might be labouring driving on level ground at 100kph because the engine is struggeling to get enough air/ fuel to develop the 17-20 KW it takes to do 100 kph at the lower revs. you have to change down for a headwind or a slight hill to maintain 100kph.

correct gearing is a balance. your reving harder but you can still put your foot down and get enough acceleration to hit 110 in say 5-7 seconds from 100. this means you also have enough power to fight a 10kph headwind, or a small hill without down changeing.

over gearing, what i have, means your using more fuel to drive down hill and on level ground. it has poke in 5rd, but im doing 5000rpm before i hit 120kph. im doing 4170rpm @ 100kph, using 13l/100k.

over gearing is much better for off road but.

without reduction i find i can sit in 5th at 80kph and get 5.6L/100k if i only only sit on 80. with a 30ish % reduction, that fuel use goes up to 6.8l/100, still doing 80. extra (unnecicary) revs uses more fuel for the same ammount of developed power.

[henno]

Jezza86 wrote:

5rd

Is that when over-gearing turns 5th into 3rd?

[Jezza86]

Well funny you mention it. My fifth is geared lower then my old 4th, so it might be 3.89th

[Johnb6249]

Thank you all,sounds like it's just right.The only time I've noticed the gearing being too high is when going down hill in 4wd low range,maybe it's the larger wheel size?Overall for what I do with it the gearing should be fine.

[Gwagensteve]

John, you have much larger to than standard tyres and these are reducing your effective gear reduction. If you have stock gearing I'd doubt the gearing is ideal with 235's for anything in particular.

I'm pretty sure a Jimny or Sierra requires more than 20Kw to push it down the road at 100km/h. I'd say 20Kw is about right for 80km/h. I get about 40hp/30Kw based on the average guy getting 10l/100km out their car at 100km/hr.

That's based on fuel use of 0.5lb/hp/hr, which is a pretty sensible constant.

I'd been keen to see some overlays of Sierra and Jimny power/torque curves. With that 40hp in mind, I'd be interesting to see what revs that power figure was developed at on both the G13A and G13BB/M13.

In any case, no problem with circa 4K indefinitely.

Steve.

[Jezza86]

your probably right steve, looking at the jimny crew dyno, if my calcs were correct in 5th a VVT manual jimny would be using less then half its available maximum power output at 3500rpm
which would be awasome, but isnt what we observe in the real world.

[MrRocky]

I think between 3700 and 4100rpm for most suzuki engines in sierras keeps them driving pleasant at 100-110 with 235/75 or larger tyres

[shep]

Last year I drove 9000km in 10 days towing a heavy trailer and cruised at 4800rpm at least 90% of the trip. Didn't use a drop of oil and the car car loved it.