[Kaizer Sozay]

Originally Posted by drifter

In 5th you will not achieve top speed, the gear is for cruising. Use 4th gear for top speed. You will notice, if you were doing 140, the minute you shift to 5th, your speed would drop.

Drifter

Pls elaborate on why the top end drops when you move to 5th gear?

[drifter]

Because, the gearing is the tallest in 5th (overdrive gear). The engine along with the taller gearing is unable to overcome the aerodyamic forces acting on the car. Hence the drop in speed.

Generally the difference is more apparent in smaller capacity engines.

Drifter

[mtnrajdeep]

Originally Posted by SLK

Moreover, I assume this 110-120km/h in the 5th gear was done only with one person aboard, b'coz with something like 4-5 people 120km/h is ok for that car.

Well, the 110kmph in 5th was attained with 3 persons on board and a little luggage. I got to about 120 kmph in 5th with 2 persons on board and no luggage. I guess I will have to try out the max in 4th. I just got 185/55 profile tyres fitted with alloys and was able to do 100 kmph in 3rd with 2 persons on board.

[rks]

Originally Posted by mtnrajdeep

Well, the 110kmph in 5th was attained with 3 persons on board and a little luggage. I got to about 120 kmph in 5th with 2 persons on board and no luggage. I guess I will have to try out the max in 4th. I just got 185/55 profile tyres fitted with alloys and was able to do 100 kmph in 3rd with 2 persons on board.

Was your fifth gear top speed of 110-120 kmph achieved with 185/55 tyres? Then that may not be surprising because your tyres are heavily oversized for a Zen and your top speed is expected to drop due to higher rolling friction (although I am not sure if the top speed will drop that much). Lighter alloys should help a little in top speed/handling. By the way, what size alloy wheels are you running (dia and width)? You also have to take into account speedo errors if your upsize does not match the original rolling radius. Further you should try out your top speed on a fairly smooth, level road; a rough road surface will bring down the top speed.

I have fitted 13X5J alloys on my Santro and with stock 155/70 tyres, I notice a definite (but not phenomenal) increase in pick-up of the car in all gears. No noticeable change in 5th gear top speed (140-145 kmph on level ground), but today I pushed the car in 4th gear and went up to 140 kmph (and still increasing). There is a definite increase in 4th gear top speed -- earlier it used to be a struggle to get to 130 kmph in 4th gear.

[mtnrajdeep]

Originally Posted by rks

Was your fifth gear top speed of 110-120 kmph achieved with 185/55 tyres?

By the way, what size alloy wheels are you running (dia and width)?

The top speed was acheived on the standard 145/70 profile tyres. I dont know the size of the alloys .... got them from z_classe just yesterday...they are of the standard diameter though as the spare is a 145/70 on the same alloys. The overall change in dia when I checked through a tyre calculator link on t-bhp came to about 0.1%

[blueraven316]

My Zen's running on 195/45 14Rs, all speeds are speedo reads ,
1st gear top is 45 KMPH
2nd gear top is 80 KMPH
3rd Gear Top is 120 KMPH
4th Gear Top is 145 KMPH
5th Have seen a speedo read of 150 on the highway
But that comes only when you upshift after 140 KMPH from 4th Crusising top speed is about 130 KMPH on the 5th Gear.

The first 3 gears though you need to pull the hell out of the vehicle to achieve that which I don't do, comfortable speeds on each gear are
1st - 40
2nd - 75
3rd - 115
And this way you don't over revv the engine and it transfers decent amount of torque going into the next gear also.

[mtnrajdeep]

Originally Posted by blueraven316

The first 3 gears though you need to pull the hell out of the vehicle

Thanks for the info blueraven316. I have never revved the car this much till date and the feel that the sound of the engine at 100 kmph on 3rd gear itself was too much. Need to get a tachometer so that I can understand the engine's rpm and power delivery better!!

[kpzen]

Originally Posted by mtnrajdeep

Thanks for the info blueraven316. I have never revved the car this much till date and the feel that the sound of the engine at 100 kmph on 3rd gear itself was too much. Need to get a tachometer so that I can understand the engine's rpm and power delivery better!!

100kmph in 3rd will be very noisy n wont sound that good with a stock exhaust system.....Pls dont try this on regular basis...

[mtnrajdeep]

Originally Posted by kpzen

100kmph in 3rd will be very noisy n wont sound that good with a stock exhaust system.....Pls dont try this on regular basis...

Yeah, its very noisy...was the first time I tried this since I started driving! Any idea on what the rpm would be at 100 kmph in 3rd gear?

[kpzen]

Originally Posted by mtnrajdeep

Yeah, its very noisy...was the first time I tried this since I started driving! Any idea on what the rpm would be at 100 kmph in 3rd gear?

Sorry i dont have a rpm meter...!

It should be around 5000rpm

[SLK]

Originally Posted by mtnrajdeep

Any idea on what the rpm would be at 100 kmph in 3rd gear?

Well, theoretically if you get to 120 @ 6500rpm then the 100 should come around 5416rpm

[mtnrajdeep]

Originally Posted by SLK

Well, theoretically if you get to 120 @ 6500rpm then the 100 should come around 5416rpm

Is this for the Zen? Carb or Mpfi?

[Akshay1234]

Originally Posted by dceite

How is it different for a Diesel vehicle? For example I read somewhere that Swift VDi top speed is achieved in 5th gear, not in 4th.

i think it depends on the car.

[jesal]

my carb zen dont think could touch 45 in first there was something wrong with my engine. people kept saying its good i never got the fun people enjoyed with their carb zens i was forced to swap... not sure now never had fun with the older engine ways. after the swap i dont think this counts but here goes

1 : 65-70 i still have to rip it properly i think it shall touch 70
2 : 120
3 : sorry still do not have the courage yet...

[SLK]

Originally Posted by mtnrajdeep

Is this for the Zen? Carb or Mpfi?

too.... I don't know!...

Maruti MPFI's surely have a 6500rpm redline.. I don't know about the carb zen.... BUT should be the same.