[Dave_3]

As a slightly sad footnote to all this ...

I was in my Dealership the other day and expressed interest in updating my E92 335D for one of the very last E92 335Ds, while knowing that the new F32s are still some way off.

Sadly, the news back was that the last remaining slots for any E92 335Ds are now exhausted. My Dealer could not get any slots at all.

So, no more new 335Ds will be available.

Won't stop the debate here. Carry on gents.

D.

[Guvernator]

Torque is of course a factor, a massive plus point for diesels and is often the reason why diesels feel real world fast. Some of the torque figures that modern diesels can produce are quite frankly astounding.

However if you want torque in a petrol engine too it's easy, just buy a bigger engine or strap on a couple of turbo's (or do both). Torque AND revs, job jobbed. You get to have your cake and eat it

[Subzero2003]

Judging from the last few posts, i think petrol and diesel drivers on E90post are close to agreeing about something!

[Subzero2003]

Originally Posted by Guvernator

Torque is of course a factor, a massive plus point for diesels and is often the reason why diesels feel real world fast. Some of the torque figures that modern diesels can produce are quite frankly astounding.

However if you want torque in a petrol engine too it's easy, just buy a bigger engine or strap on a couple of turbo's (or do both). Torque AND revs, job jobbed. You get to have your cake and eat it

The one of the major plus points many diesel drivers see in diesels (the torque) will soon become much less exclusive to diesel cars.

Pretty much every new petrol engine coming from mainstream manufacturers is going to be turbo'd/supercharged, which means lots of low down torque for most petrol engines, as well as high revving grin inducing stuff at high revs and good MPG!

[Guvernator]

Originally Posted by Subzero2003

The one of the major plus points many diesel drivers see in diesels (the torque) will soon become much less exclusive to diesel cars.

Pretty much every new petrol engine coming from mainstream manufacturers is going to be turbo'd/supercharged, which means lots of low down torque for most petrol engines, as well as high revving grin inducing stuff at high revs and good MPG!

Spot on, next we'll have someone saying hybrids are a good idea

[kenno78]

Originally Posted by Guvernator

Spot on, next we'll have someone saying hybrids are a good idea

Ahem.

http://en.wikipedia.org/wiki/Porsche_918
http://en.wikipedia.org/wiki/BMW_i8

[Guvernator]

Originally Posted by kenno78

Ahem.

http://en.wikipedia.org/wiki/Porsche_918
http://en.wikipedia.org/wiki/BMW_i8

While I certainly applaud the efforts and hybrids are probably inevitable, I don't think batteries are the way forward. Battery tech is moving far too slowly for them to be viable anytime within the next decade at least. Modern ICE engines are almost as efficient now and getting better all the time. Plus they don't have the drawback of having to lug around several hundred kilo's of batteries and then disposing of them properly at the end of the cars life.

I'm not sure what the power source of the future will be, it's probably a good bet that diesel\petrol will go at some point but I don't think batteries are the answer either as they are a dead end tech imo.

[kenno78]

Originally Posted by Subzero2003

Pretty much every new petrol engine coming from mainstream manufacturers is going to be turbo'd/supercharged, which means lots of low down torque for most petrol engines, as well as high revving grin inducing stuff at high revs and good MPG!

It's difficult to have your cake and eat it. To get the low end push, you have to reduce lag. Reducing lag means smaller turbo. Smaller turbo means no puff at the top end. Even with variable geometry turbo's I don't think they can do it all.

Twincharging is also relatively new in mainsteam cars even though it's been around since the Group B days.

[HighlandPete]

Originally Posted by kenno78

It's difficult to have your cake and eat it. To get the low end push, you have to reduce lag. Reducing lag means smaller turbo. Smaller turbo means no puff at the top end. Even with variable geometry turbo's I don't think they can do it all.

Twincharging is also relatively new in mainsteam cars even though it's been around since the Group B days.

The manufacturers like BMW, have used the 'big and little' turbo to virtually overcome problems both ends of the rev range in the diesels. No reason for petrol not to have various combinations to get similar results.

As an example from kit already out there, run a twin scroll turbo at the bottom end, virtually lag free boost, and bring in a single fixed vane big 'un at higher revs to easily put an extra 50bhp or so at the top end, without any issue at all. Maximise torque and get a decent power curve.

HighlandPete

[kenno78]

Originally Posted by HighlandPete

The manufacturers like BMW, have used the 'big and little' turbo to virtually overcome problems both ends of the rev range in the diesels. No reason for petrol not to have various combinations to get similar results.

As an example from kit already out there, run a twin scroll turbo at the bottom end, virtually lag free boost, and bring in a single fixed vane big 'un at higher revs to easily put an extra 50bhp or so at the top end, without any issue at all. Maximise torque and get a decent power curve.

HighlandPete

Just begs the question though Pete. If it were simple, why haven't they been doing it (for petrol). The last sequential turbo car I can remember was the Supra.

In terms of kits. Sure. But it's very much like the Veyron. Tuners could make 1000bhp cars, but the difficultly is making one that will last.

[HighlandPete]

Originally Posted by kenno78

That can only be said from the perspective of a 335i owner. Torque is a significant factor for how 'drivable' (read flexible) a car's engine feels and is really the thing that you need in day to day driving. Smaller capacity normally aspirated petrol engines can't compete with similar capacity forced induction diesels.

I agree with your comments, that is how it has become in reality.

What I remember, the level playing field changed... both petrol and diesel were for a long time, mostly NA. Designs moved in the diesel's favour when turbos were fitted and particularly when direct injection was added as well, to get the real economy gains. Generally the idea of petrol turbos raised a 'gasp' with most drivers, but for some reason didn't have the same resistence with the pioneering diesel drivers. Even though turbo issues are still the dreaded failure point, which often wipes away any savings for running a diesel. For some reason even petrol drivers bought into the hype that diesel engines were solid and were 'simple' engines and would give mega miles without issues. Partly true from an historical perspective, but not so with the modern designs.

So generally petrol engine design got left behind, while the manufacturers went on the mad dash to design the high performance diesels, and diesel engine performance leaped forward very fast indeed. Now it seems the makers have woken up to the fact they can do virtually the same with petrol and get better engines which are more efficient as well.

If you read the technical papers you will note we are on the way to multi-fuel IC engines, where the differences will merge even more.

From my perspective, petrol engines will see the biggest leap forward in the next few years, as emissions from diesel is the big issue and the complexities of enhanced emission controls to get to higher tiers of clean running are the diesel challenge. Becoming more costly to fit and of course service, over the life cycle of the engine.

So the playing field is likely to level out again. Certainly the current BMW turbo petrol engines hint at the gap closing for performance, driveability and real world economy.

HighlandPete

[JNW1]

Originally Posted by HighlandPete

Certainly the current BMW turbo petrol engines hint at the gap closing for performance, driveability and real world economy.

HighlandPete

Indeed! I see that when he wasn't pushing it Chris Harris managed 38mpg from the latest M135i which can't be bad from an auto that's also capable of doing 0-60 in 4.5 and cracking 100 in under 11 (those were supercar figures when I was a lad!). If it wasn't so damned ugly I could quite fancy one myself (sorry, bit off topic with this post!).

http://www.pistonheads.co.uk/news/de...?storyId=26529

[phil200tdi]

Things have come a long way (4mins in):

http://youtu.be/DRPMazBDrX4

[Subzero2003]

Originally Posted by HighlandPete

The manufacturers like BMW, have used the 'big and little' turbo to virtually overcome problems both ends of the rev range in the diesels. No reason for petrol not to have various combinations to get similar results.

As an example from kit already out there, run a twin scroll turbo at the bottom end, virtually lag free boost, and bring in a single fixed vane big 'un at higher revs to easily put an extra 50bhp or so at the top end, without any issue at all. Maximise torque and get a decent power curve.

HighlandPete

Surely variable vane turbos render twin turbos useless for most applications where you dont need big power? You get the low end pick up, and the power at the top from a single turbo?

[HighlandPete]

Originally Posted by Subzero2003

Surely variable vane turbos render twin turbos useless for most applications where you dont need big power? You get the low end pick up, and the power at the top from a single turbo?

The VGT/VNT have been around for many years now, I was driving the VW Passat with one in 1998, and yes they do a very good job in improving turbo diesel performance. Give a higher power/torque output, compared to a fixed vane turbo on the same engine, as the fixed vane has to be a compromised size, to give a sensible mid range. Which means slower spool up and runs out of puff at the top end.

But looking at the BMW "two-stage twin-turbo" (335d/535d) we clearly have the benefit of improved low end pick up and at the top end constant pull to the limit, where the single VGT (330d/530d) will be running out of grunt.

We run VWs in the family, and having had the 2.5 TDI engines with a single VGT and now the 2.0 TDI engines with the "two-stage twin-turbo" setup, it is clear we have better power development and a wider spread of torque, even with the smaller engine capacity.

The VGT is the best compromise for the bigger market, but for the high end performance diesel, 'two-stage' whether sequential or sequential/in-series turbos give the edge for better performance. Bi-turbos have been used with diesel engines, but the small and large 'two-stage' work better for widest torque development.

HighlandPete

[NoelWatson]

Originally Posted by xPETEZx

I haven't found much to say the N53 Petrol engine has any relaiblity issues?

Can you name a more unreliable engine in recent history?

[NoelWatson]

Originally Posted by shrink

Can also tell you've not spent a lot of time in a petrol straight six...the sound at high revs is absolutely heavenly, and in some ways one of the more classic engine notes. My old 330 and 328 sounded much the same. In fact I'm considering a performance exhaust to get even more joy from the sound of the petrol.

The 530d sounded like a tractor and no exhaust in the world will improve that

The N53 sounds very diesel-like at lower revs

[shrink]

Not really

[NoelWatson]

Originally Posted by shrink

Not really

It did to me. I had to get the salesman to start another up to prove my engine wasn't faulty. Not a patch on the creamy BMW sixes of yesteryear.

[shrink]

Admittedly my old 328 was creamy as a thing made of cream. The 330 a bit less so just by nature of being more aggressive sounding. My current car is pretty smooth, a bit noisy at idle but still creamy at low revs around town.

All round though, the smoothest was the early e46 328 and that had 150k on the clock!!

[ng04ryl]

Diesel all the way lol