[Ashley Nair]

The maximum speed I could achieve on my 1999 Marshal 2WD with MDI 3000 engine was 105kms/hr( speedo indicated).There was no protesting sounds from the engine, anyhow.I could go at that speed only for a few kms on a lonely stretch of road and had there been a slightest tap on the brake pedal......I am sure I would not have been here to write this.

The comfartable cruising speed is 80kms/hr

[Samurai]

My cruising speed on a good highway is 80kmph, highest I have done is 95kmph somewhere near Cochin with a long runup. Yes there is speedo error I suppose, but I have much bigger tyres than OE. Does that mean I was going faster than that?

[desertfox]

I guess this is not specific to Indian 4x4.

I have done 190 kmph in my Landcruiser 100, 4700 cc, V8 and 180 in my landcruiser Prado 3400 cc V6.

Well, I did it but it is not recommended, this was done on an 8 lane highway, and was not a smart thing to do at all. And I am definetely not recommending anything of this sort to any youngster to attempt.

A 4x4 vehicle with a high centre of gravity is not at all suited for high speed driving as a sportscar is unsuitable for offroading.

In India what would it be ?

Mahindra Bolero - 120 kmph
Jeep Cj3b - 100 kmph
Maruti Gypsy King - 130 kmph

[MexXxentric]

110kmph on 1994 MG410W with stock nylons and K&N conical filter.
60kmph is the best for relaxed cruising and best average

[vinod_nookala]

[quote=JeepMkd;1479764]

The maximum that I can squeze from my 1970 CJ-4 (diesel swap) is 63km/h. It was faster with the Hurricane petrol, but at a cost. I considered changing the transmission with a 4 speed from these ones, but I can't find any transmission.

JeepMKd
63kmph is way too low!! Changing to a 4 speed gearbox will not help as the top gear ratio on both gearboxes are same i.e1:1. 4 speed gearbox will give you better tractability off in off road conditions as 1st gear is much lower @3.986:1.

The culprit seems to be your 5.38 axle ratio and low revving Ford diesel which you have retrofitted in your vehicle. If you want to improve the cruiseability of your jeep then revert to petrol as it is capable of 90-95Kmph and will cruise all day long at 60-70 kmph. If petrol is out of question then change your diff ratio to 4.27 or 4.88 depending upon how powerful and rev-friendly your ford diesel is.

Please check your speedo meter if it is showing true speed, i feel it is showing less. Futher please post the power and torque figures of ford diesel engine which you have retrofitted.

[vinod_nookala]

Originally Posted by Samurai

My cruising speed on a good highway is 80kmph, highest I have done is 95kmph somewhere near Cochin with a long runup. Yes there is speedo error I suppose, but I have much bigger tyres than OE. Does that mean I was going faster than that?

Bigger tyres generally mean greater top speed. Since your indicated top speed was 95 kmph it could be the true speed (cancelled with speedo error which generally becomes almost 5kmph nearing top speed in old vehicles). Since your diff ratio is 5.38 it is highly unlikely that it will do more than that.

[kittigadu]

On my mm550XD (4Forward & 1Reverse)

Top speed 110 kmph.
Speed at which i find the engine running smoother and quieter than normal 75-80 kmph.
My highway speed 70-80 kmph.

StarAqua(Vijay) keeps telling that with smaller tyres, i could reach much higher speeds than these. On sandgrips, my rolling distance is very very low.

Regards,
Krishna.

[sreerajunnithan]

Originally Posted by vinod_nookala

Bigger tyres generally mean greater top speed.

Originally Posted by kittigadu

StarAqua(Vijay) keeps telling that with smaller tyres, i could reach much higher speeds than these. On sandgrips, my rolling distance is very very low.

Regards,
Krishna.

Kitti,

I guess it's the other way around.
May be i am wrong!!!

--Sree--

[vinod_nookala]

Originally Posted by sreerajunnithan

Kitti,

I guess it's the other way around.
May be i am wrong!!!

--Sree--

Sree,
Top speed doesnt depend upon only size of the tyre purely, though generally bigger tyre means higher top speed. Engine must have enough grunt to support the momentum in its peak rpm. Too big tyres with high rolling resistance will actually reduce top speed. Better top speed and fuel economies possible on thinner and taller tyres due to low rolling resistance and light composition.

For example an Armada had 15 inch 70/ 75 profile puny radial tyres but still did 105 kmph with 5.38 ratio!! There are so many formulas to find out top speed based on your final drive, tyre size and engine red line rpm. But that seldom holds good as you will have to take aerodynamic and rolling resistance into picture. Also top speed engine peak rpm in top gear matters.

[Sha]

Originally Posted by kittigadu

StarAqua(Vijay) keeps telling that with smaller tyres, i could reach much higher speeds than these. On sandgrips, my rolling distance is very very low.

He did not suggest you to buy NDMS tyres .

[kittigadu]

I guess it's the other way around.
May be i am wrong

well,
i was wrong. Vijay was telling about the mileage and not the speed.

He did not suggest you to buy NDMS tyres

He did sha. Inspite of all its advantages etc, i am not a NDMS fan.

Regards,
Krishna.

[sreerajunnithan]

Originally Posted by kittigadu

He did sha. Inspite of all its advantages etc, i am not a NDMS fan.
Regards,
Krishna.

I was, but not anymore . But thinking about 7X16 NDMS i have seen a Jeep with same (Bhaskar's) and it looks mean!!!

--Sree--

[GoSlow]

Gypsy King 1997 (Carb)
- Top Speed 120 kmph
- Comfortable speed 70-80 kmph

After Nissan 1.7L Diesel conversion mated to Gypsy gearbox and T Case
- Top Speed 90kmph
- Comfortable Speed 70kmph

Cheers
Ankit

[dwaraka]

Originally Posted by vinod_nookala

@DKG- B275 engine official top speed is 72 kmph max. So you mean to say you feel comfortable when your jeep is redlining?

@Dwaraka- Gypsy 1000 cc top speed is 110 kmph (tested) Your 135 kmph on express way has to do with fair amount of speedo error

@Beejay- Your CJ340 has 5.38 ratio. Mahindra classic with 4.88 ratio was tested 95 kmph true top speed. Hence your true top speed should not be more than 85-88 kmph
@sreeraj- 120 kmph is possible in 4th gear and i doubt if this is possible in 5th gear. Bolero top speed 2wd (true speed) is 125kmph in 4th gear settles at 115-118 in 5th gear


On my MM540 4wd i have achieved 90 kmph (true speed) ...matched it with Honda civic digital meter. I still could go a bit more, may be 3-5 kmph. Comfortable speed 75-80 on highway 50-60 in city. Engine noisy between 60-75, revs smoother when i cross 75. Brakes highly inadequate for emergency stops @ 70-80 kmph. May opt for Disk brake soon.

Mileage- Iam yet to check but should give me 9 kmpl in city. Tyres- 235/70 R16 HT

p.s- All the true speeds mentioned are from magazines of test drives of these vehicles in past

Vinod Nookla,

This doubt was expressed in another forum too. But my regular speed on high was between 100 -110 kmph on 1000 cc engine. 135 kmph was for sure achieved by me. Not speedo error. This is possible with gradual build up of speed without braking and changing gears.

[vinod_nookala]

Originally Posted by dwaraka

Vinod Nookla,

This doubt was expressed in another forum too. But my regular speed on high was between 100 -110 kmph on 1000 cc engine. 135 kmph was for sure achieved by me. Not speedo error. This is possible with gradual build up of speed without braking and changing gears.

Dwarka,
Since you drove it you know it better. But elsewhere in this discussion as well people have said their's 1000 cc topped at about 110 kmph. Your Gypsy is a Hardtop so heavier, your tyres are wider too (even the old ones). All this adds to the drag. Your 1000 cc top speed was even more than 1300 cc engine and 5 speed gearbox! If 135 is true speed then it must be a very special Gypsy!!