[CPH]

Originally Posted by Sutripta

What is Diesel specific tolerances?
What effect would the differences in the nature of fuel delivery and of combustion have on rev limits?

Regards
Sutripta

The Diesel engines uses an effect the petrol engines can't live with. The much lower flash point of the petrol makes petrol much more volatile than Diesel. Pinging, detonation. premature combustion or however you want to call it is a killer for the engine when it happens in petrols. The Diesel only exists currently because of the very same effect. This means added strength.

Additionally the much higher compression pressures in the Diesel require strength accordingly. The shape of the piston adds on even more weight.

What a lot of people forget is that the forces on the pistons on engines revving to 4000rpm will be in excess of 3000G. In other words each 25 grams of piston have the effect of 1 average adult at 1G. 25 grams is not a lot in a piston, but very welcome by tuners if it can be removed.

The biggest problem in F1 engines is the piston and conrod design. Make it too light with the materials at hand and you will suffer longevity problems, but have the advantage to lose less torque on the crank shaft and hae less strain on other components. Make it too heavy you will lose power because you can't rev it as high to start with and you will need more engrgy to get there. Additionally other parts need more etrength.

The Diesel combustion is more complext than the petrol combustion. The thermal changes on the Diesels are more cumbersome, which means with the materials used the tolerances are sluightly different to compensate for different expansion rates. The additional weight as well as the higher expansion pressures. do not allow for piston speeds as in an equal petrol bore stroke ratio.

[Sutripta]

^^^^
Hi,
The necessities of a sturdier build for Diesels, and the implications of heavier reciprocating masses is well known. However I'm still confused by what you mean by 'Diesel specific tolerances'.

What is expansion pressure? BMEP? Or measured from (the equivalent of) indicator diagrams? How does it affect piston speed?

I thought in Diesels, (esp pre CRDI), the fundamental rpm limit was because of the nature of the fuel delivery, and combustion, rather than the engineering limit caused by higher reciprocating masses.

Regards
Sutripta

[FastLove]

Was out of action for a while due to work and also was taken ill for a brief period.

Managed to hit the dyno again during Peters (CPH) mumbai visit.

Updates on my Linea 1.4 N.A (ECU Remapped - Refer Dyno maps posted by GTO pg.1) :

1. Got my Clutch replaced the very next week after the Dyno meet with GTO and REhaan. This was done within warranty by FIAT as a "Goodwill" gesture as mentioned in the TASS note put up for my case. I used best of my persuasive skills here.

2. Got the AIR (Air Intake Revision) fitted on 22nd December after Peter landed in mumbai. The First Linea he ever saw and worked upon . Right , Peter?

I am attaching the Dyno Graphs Before and After the AIR was fitted.

My Sincere Observations :

1. I had a good experience since the Remap and the difference was felt by other Linea Owners who drove my car even during the FIAT Ranjangaon Plant Visit on Dec. 3rd. Infact i drove other Linea 1.4 N.A and could immediately feel what i had gained in terms of the Peppiness after the Remap.

2. Experience with AIR : After Meeting Peter and within half an hour of shaking hands with him , he was under my car and within 5 minutes my AIR was fitted.
- The Overall driveability has gone a notch higher and i mean to a level where the smile is permanently etched on my face in all driving conditions.
- a gentle tap and the car moves from 1000rpm on 5th gear effortlessly. The lower gears have got peppier and i just love whatever the car is doing now all with a gentle tap on the accelerator pedal

- on a test run before we did the dyno ..we clocked 13.2 sec for a 0 to 100 run .
We had a stock Linea 1.4 N.A. side by sude that best clocked 14.7 sec. for the same stretch.


Other Observations :
On the dyno run day we had a Punto 1.2 (67BHP as per manufacturer) with following figures without AIR : 50BHP on the Wheel
and with AIR : 58BHP on the wheel

Noteworthy is the fact that the stock showed 50bhp that is a loss of 25% on the wheel.

Strictly my opinion here is - linea 1.4 with that calculation should have a stock bhp of 67bhp on the wheel. My car showed 80bhp on the dyno run on 30th Oct (with bad clutch) and 78BHP on 3rd December (after clutch replacement, very strangely) . Sadly , we did not do a dyno on a stock Linea 1.4 N.A. (which i would be eager to know the figures of)


Overall, My mathematics and "wishful thinking " tells me that even if I take a 17% loss on wheels... I am driving a 100bhp car now after the AIR fitted . My last dyno result with AIR showed 83BHP on the wheels.

Note - Linea 1.4 N.A. has 89BHP Power as stated in the manual.

The most notable difference is the Torque that is what i am enjoying more than the BHP gain which as you must have noticed is much more in the Punto 1.2 that gained 8 BHP after fitting AIR.


I will upload the data of the 0 - 100 run too shortly.

[FastLove]

Before AIR
0-100: 13.83s
0-110: 16.17s
1/4m ET: 19.24s
1/4m TS: 121.6kph

With AIR
0-100: 13.23s
0-110: 14.3s
1/4m ET: 18.92s
1/4m TS: 123kph

Improvement
0-100: 0.6s
0-110: 1.87s
1/4m ET: 0.32s
1/4m TS: 2.4kph

[revtech]

are the 0-100 and 1/4 mile time done on the dyno ?

[CPH]

Originally Posted by revtech

are the 0-100 and 1/4 mile time done on the dyno ?

A dyno is never real time, which would make such figures absolutely useless.

The are tested on a set strip and evaluated with a g force meter in real time.

[FastLove]

Originally Posted by revtech

are the 0-100 and 1/4 mile time done on the dyno ?

In layman terms - a dyno only gives you BHP and Torque figures as you can see on the graph above.

For a 0- 100 run you need to actually drive the car on a open strip of road with a software tool running on your phone/similar device that records your run in real time ( in our case , an iphone app that worked on Gforce ).

There are apps available in android that uses GPS to give you similar data ..eg. DynoMAster

[CPH]

Originally Posted by FastLove

In layman terms - a dyno only gives you BHP and Torque figures as you can see on the graph above.

For a 0- 100 run you need to actually drive the car on a open strip of road with a software tool running on your phone/similar device that records your run in real time ( in our case , an iphone app that worked on Gforce ).

There are apps available in android that uses GPS to give you similar data ..eg. DynoMAster

Adding ti this I can speak for the accuracy of the ipod software, which was by ourselves repeatedly tested at Sant Pod showing a stunning accuracy time after time.

[revtech]

Originally Posted by FastLove

In layman terms - a dyno only gives you BHP and Torque figures as you can see on the graph above.

For a 0- 100 run you need to actually drive the car on a open strip of road with a software tool running on your phone/similar device that records your run in real time ( in our case , an iphone app that worked on Gforce ).

There are apps available in android that uses GPS to give you similar data ..eg. DynoMAster

did you use dyno master ? where did you do the 1/4 mile run ?

[CPH]

Originally Posted by revtech

did you use dyno master ? where did you do the 1/4 mile run ?

In my previous post was stated on what the runs were done.

The runs wer done on a public road repeatedly under the same conditions. This is the strech I will use for regular testing but don't want to disclose in order to prevent milking our pockets by certain people in uniforms.