Diesel vs Petrol FR - Which is quickest?

[flakmunky]

Here's some data from Seat (manual gearbox):

Leon FR TFSI
Top speed: 229
0-100 km/h (s): 7,3
80-120 km/h (5th) (s): 7,0
80-120 km/h (6th) (s): 8,9
0-1000m (s): 27,6

Leon FR TDI
Top speed: 214
0-100 km/h (s): 8,2
80-120 km/h (5th) (s): 8,2
80-120 km/h (6th) (s): 10,5
0-1000m (s): 29,3

I'm no expert but here are my thoughts on why the TDIs 'feel faster' even though the manufacturers figures say otherwise. Expect the ravings of an idiot... You've been warned!

I used to have a Golf GT TDI and when I first bought my 350z I wasn't as impressed with the Z's acceleration as I thought I would be. I was expecting to be pushed back in my seat like I did in my Golf. It wasn't until an extended test drive that I realised the power delivery was completely different. There was no 'peak' in the power, the Z just pulled from 900rpm through to 6500rpm with no let up.

The petrol FR is similar, however the FR is FI and the Z was naturally aspirated so I can feel the turbo spin up and give a mild kick. The thing is, the FR pulls right the way up to 6500rpm (I find the power peaks at around there and although my DSG likes to hold the gear to the redline I prefer to change a little sooner).

So the diesel 'feels' quicker because the kick is delivered over a couple of thousand rpm whilst the petrol is delivered over twice that. Therefore the 'kick' doesn't feel as harsh.

Incidentally, the Z had the same torque as the Golf but had a much flatter torque curve; the torque was delivered over a much larger rpm range.

You guys who are loving your 3rd gear, imagine if your redline was 2500rpm higher than it is now... 30 to well over 90 in 3rd, then drop it in to 4th & it pulls again as if you were still in 3rd doing 40... And then you still have another 2 gears to go! Ah! I miss my Z...

Before the Traffic Police come out in force, I tracked my Z - you don't buy a car like that and just drive it on the road Unless you are a very well paid hairdresser!

 

[simon76]

one the seat track day at Knockhill before Christmas, someone asked the instructor which was the fastest, the petrol or diesel FR. She said they had all driven both around the tracks they had been to and that there was nothing between them on a timed lap.

 

[chippenhamwilts]

Well, I think you all are forgetting that Seat dont use the petrol for the touring cars anymore for thier first teams, they use the diesel and its 20-30 bhp down on the petrols but won its first race easily in WTCC. Diesels are definitly quicker on the road, no competion coming out of a bend or up a hill and on the road thats where it counts. Yes you might get left by a few yards at the lights but a decent driver would be back in front at the next bend.....

 

[BanziBarn]

Dont forget to turn off ESP first.

Ah! Turn it off, that's why i've never been able to get thie launch control to work.

My take on the performance difference is that the petrol is faster but the diesel is easier to drive fast.

 

[flakmunky]

lol... I would agree Banzi...

I don't think there is much in it, either tbh. At the 60mph / 70mph speed limit 0.5s difference in sprint time is neither here nor there... a couple of car lengths?

But if makes you Oilers happy, yup, the TDI is faster than the petrol.

 

[Moley RUFC]

The only reason i went for the diesel was because of my 30k miles a year. Besides in a race the petrol would need to build up a big lead as the diesel would only be doing one fuel stop against the petrols 2/3

 

[chippenhamwilts]

if you have the 'launch control' (which I am sure it isn't actually designed for, but hey who cares) you don't need to turn ESP off for it to work. Works just fine on mine with or without esp.

 

[Moley RUFC]

if you have the 'launch control' (which I am sure it isn't actually designed for, but hey who cares) you don't need to turn ESP off for it to work. Works just fine on mine with or without esp.

Correct

 

[Michael B]

Correct

Indeed, and acutally the 3k limiter for the 'launch' only works with the ESP TURNED ON!

 

[johnbev]

On the seat track day I drove both the petrol and diesel fr, 4 adults up in the car and there was very little in it at all. We swapped in and out of cars all day. The Cupra was definitely quicker but the fr`s were pretty much the same. The instructor also agreed and said that the difference is only noticable by hanging on to the revs in the petrol which can obviously rev higher. But most of us drive at mid revs and get decent performance similar to a petrol and rarely "wring the neck" of the car where the petrol has the edge. That is the beauty of a tdi, power and economy without thrashing it

 

[kingkongsfinger]

I have done 80k in 3 years in a diesel FR and its quick if you "know" how to drive it "correctly". If you rev it to much or have poor clutch control you loose a lot of time in accelaration.

I have "done" a lot of much faster cars over fast b and a roads because of the torque of the diesel engine.

Oh another thing no one has mentioned you need to be able to brake properly on a and b roads, alot of time is gained when you very late/heavy "out" brake someone. With a diesel ramming it down a few cogs when braking uses the engine braking to great effect.

Have you guessed im a SALES REP yet?????

 

[BanziBarn]

Indeed, and acutally the 3k limiter for the 'launch' only works with the ESP TURNED ON!

Tried it with it off and you're right. But doesn't work with it on either so I guess I'm missing this feature!

 

[SpursMadDave]

Tried it with it off and you're right. But doesn't work with it on either so I guess I'm missing this feature!

You will know you have it right when you are in 1st with clutch down and you can only rev to 3k...... esp on or off depends how much you value your rubber.....

 

[chrisboyle999]

petrol.

in gear its quicker too.

 

[GREY 225]

I had fabia VRS remapped to around 185 hp and 300lbs of torque before LCR,my LCR is also remapped with around 275hp and 300lbs of torque,so it has the same level of torque as my VRS,so was VRS as quick as LCR,err no,it would be left for dead,VRS was a quick car theres no doubt but the extra power of LCR makes it a really fast car,torque is good for in gear performance i agree but dont forget cars such as civic type R have little torque but would have no problem in keeping up.I also found VRS had a very narrow power band which didnt help in corners.Im not slating diesels,if i did more miles i would have the 140/170 and good performance/fuel economy that goes with them,but as i dont do big milage ill stick with high power petrol.

 

[BanziBarn]

You will know you have it right when you are in 1st with clutch down and you can only rev to 3k...... esp on or off depends how much you value your rubber.....

That'll be on then!

But anyway, i've tried it loads of times and my car definatly doesn't have this feature :-(

 

[P0LKR]

My mapped Leon Mk2 is just mental. It has all the torque of my last mapped diesel and more but has an extra 130bhp in the same model of car!! Tarmac eater

 

[CandyCupra]

You will know you have it right when you are in 1st with clutch down and you can only rev to 3k...... esp on or off depends how much you value your rubber.....

In my car this will only work with ESP switched on!

 

[cuprascott]

Dont forget to turn off ESP first.

Nope - ESP needs to be on.

 

[SpursMadDave]

Nope - ESP needs to be on.

Definitely works with ESP on, and tried it with ESP off too and worked the same... but everyone seems to have different experiences with this, for some doesnt seem to work at all...

As for the original debate a few have said that the TDI is underestimated and i think the most telling comment is from the track day drivers who said no difference at all, so if you know how to drive a diesel then you can keep up with the petrol