[Jaggu]

Pedal to metal will NOT be a good idea, full acceleration according to the driver rather. There will be some driver input difference, but should not be very different with multiple runs.

Getting to tire size then air pressure also will matter, lets start off and record as much as details. Let me give it a try and will confirm on start speed also.

[d3mon]

Didn't quite get you there.

Pressing the accelerator pedal fully would surely get the best acceleration out of the car, right?

[Jaggu]

My experience or rather my style is giving accelerator inputs as the engine responds, which gives better results. I might be wrong hence i said i will try couple of runs during the weekend and then confirm.

[d3mon]

Well that MAY have been true in the olden times, when the accelerator pedal actually controlled something in the engine bay (a butterfly valve, perhaps ?) but with the advent of the ECU, the ECU will make sure that you get the best performance when you press the pedal fully.

IMO there is no chance that you'd get a better run with by modulating the accelerator pedal as the engine responds.

to measure roll -on timings consistently with our low tech equipment(friend+stopwatch)

1.find an straight road with minimal or no traffic(good luck)
2.slot it in 3rd gear run it at 1800rpm or so to begin with.
3. let the rpm drop to 1500 gradually
4.when you can hold the rpm steady at 1500 for a few seconds, you are good to go.
5.floor it
6.check time it takes to get to 3000rpm

Note
if the car is knocking/jerking when you floor it(it shouldnt normally), back off. try a higher rpm to start from, like 1700.

speeds at 1500rpm and 3000rpm in 3rd will be useful.

I agree with both jaggu and d3mon
flooring it will eliminate a lot of driver to driver variability.
throttle modulation according to engine response will give best performance

@d3mon- I get what you are saying about the best response being available when you floor it, the logic behind it is completely fine. but what i feel while driving is completely different. best response seems to be when we modulate the accelerator pedal, dont know why.

if we want to further reduce variabilty, a soft reset of the ECU by disconnecting the battery for 15 mins would also help. But thats just being a bit wierd

[Jomz]

Did anybody think of the following scenario??

Blocked airfilter -> vaccum in intake manifold -> sucks oil from the turbo bearings through the seals ->Seals go busted-> turbo clearances affected -> low boost.

you can see oil on the intake air pipes's to the intercooler, and in the intercooler.

I've seen this it a couple of heavy duty diesel engines.

[d3mon]

@ripper

In normal day to day driving, the torque ensures that just a feather touch on the pedal sends the car surging forward.

That is very close to the max acceleration one can get out of it.

But, if you press it to the floor, the ECU tries everything it can to improve performance, and succeeds only marginally. So there is a very little difference between a half press and a full press of the pedal, especially at lower rpms.

So I reiterate; Pressing the pedal to the metal will get the best timings. Engine's ECU's a lot smarter than my foot, methinks

[Jaggu]

i dont know about pedal to metal and all, but rollon speed of 40 kph is required to do any 1500 rpm take off's in 3 rd gear. Didnt time anything since i was in a hurry to get to office in the morning, maybe over the weekend.

[architect]

Originally Posted by Jaggu

Yes i actually was thinking in these terms. Is this issue limited to Maruti DDIS or is it universal for Multijet engines.

The turbo kick on the MJD is more linear and perhpas that's why any change is not noticed as easily. I have not faced any deterioration after 21.5 k kms. However, i have noticed that it seems less peppy after 5000 kms from the last oil change but I attribute that to the dirty air-filter (which I change/clean only at service intervals)

Originally Posted by Jaggu

Fiat europe uses Synthetic CF4 oil but the brand seems to be SELENIA WR any info on Indian MJD would be useful.

Fiat uses Selenia for the Linea MJD only, as the Synthetic oil is required for the 15,000 km service interval. For the 1.3 JTD, they use "Fiat oil" which I believe is a brand called VSMax (or is it Pennzoil?)

[opendro]

Originally Posted by Jaggu

My experience or rather my style is giving accelerator inputs as the engine responds, which gives better results. I might be wrong hence i said i will try couple of runs during the weekend and then confirm.

Off topic! But I too agree. Try flooring the pedal after an early shift up. It does not help. It tends to pick up better with inputs based on response.

[Jaggu]

Originally Posted by architect

Fiat uses Selenia for the Linea MJD only, as the Synthetic oil is required for the 15,000 km service interval. For the 1.3 JTD, they use "Fiat oil" which I believe is a brand called VSMax (or is it Pennzoil?)

Could you please get some more details from dealer about this oil, what grade and what spec? Or just the actual manufacturer and name.

Originally Posted by Jomz

Did anybody think of the following scenario??

Blocked airfilter -> vaccum in intake manifold -> sucks oil from the turbo bearings through the seals ->Seals go busted-> turbo clearances affected -> low boost.

you can see oil on the intake air pipes's to the intercooler, and in the intercooler.

I've seen this it a couple of heavy duty diesel engines.

Its possible I suppose, and thanks for that suggestion. definitely worth looking into. However in my case, the air filter was getting cleaned every 2000-3000kms Call me crazy, but I love this car.

But like you described, I had oil(I cant say it was engine oil for sure- oily residue would be the best term) in the turbo, the intercooler entry and exit.
I was told that's "normal". I finally justified it to myself saying that its probably coming from the EGR system.

Which is also one of the reasons why I've been hatching plots to assasinate the entire EGR system in my car for over a year. should I not bother with that then?

To me, and the MASS technicians, Oil in the intercooler and turbo was the cause of the problem, not the effect. Looks like we were wrong.

What you're saying indicates the opposite. time for a rethink.
How would oil in a turbo damage it? the oil would just get blown away, right?

Another question,
if there is vacuum in the intake manifold due to a dirty air filter, would the boost pressure sensors be able to pick it up? I could intentionally run a clogged air filter for a few kms while attached to the OBD to find out if there is actually a vacuum building.

[Jaggu]

I think Jomz scenario is a lesser probability situation in real life, unless the design is really bad and seals sub standard.

On the other hand, i remember ripper mentioning oil in inter cooler earlier also, how is the situation now when last checked? has it increased or is the same? Lil bit of oil might be a possibility due to vaporization and condensation of the charge, but something which is closer to wet is ALARMING.

Air map sensor should limit parameters if there is a huge block at air intake end, my guess.

Maybe the in house modifiers with some experience can throw some light to this issue?

When the turbo finally gave up, the intercooler was dripping oil after it was placed on its end for a few minutes. and there was a substantial amount in the turbo too, and my car was dropping oil levels rapidly. something which it had never done before. it normally never needs top ups in between services, but once the turbo failed, it needed top ups every 3-4 days.

The in house modifiers are keeping quiet fearing warranty issues of their own I think

MAF sensor will cut back on fuelling if the airflow is less, thats why intercooler cleaning and airfilter cleaning are effective in restoring performance in most cases. it just shows that some oil in the IC or dirt in the air filter is enough to cause a significant block.

[humyum]

Did the Test today.3rd Gear, 1500 rpm till 3000 rpm as suggested
The timings are- 6.4 seconds in the first run
Second run - 6.6 seconds.

So taking a mid between the two
It takes 6.5 seconds in my car from 1500 rpm to 3000 rpm in 3rd gear.

Waiting to hear from you guys
Cheers