Looking at various Petrol engined turbo cars, particularly, the VAG ones, they seem to be getting far better at extracting almost zero lag torque and horsepower, using petrol direct injection systems and advanced management.

Take the first stage of tuning these cars with sportscat or even decat downpipes, maybe a remap and intercooling upgrades. You have an even less laggy, more powerful petrol engined car.

Question is... Where does this leave us 1.9TDI users?

Do we really need much more torque at lower RPMs (say 2K-2.4K) than can be extracted at the moment? Shouldn't we try for a modest gain in torque but held over a bigger RPM range. Say, allow the unit to rev at least to 4.5-5K whilst holding as flat a torque line as possible.

J.

Isn't that what a skillfully done custom remap will give?

it's not that the engine isn't capable of doing that, it's more to do with reliablility issues. imho a few extra rpm for a tiny bit more power isn't worth it, engine wear is a lot higher at those speeds, and of course higher rpm requires more air flow to make power, so then your turbo runs out of puff and a bigger unit is needed, then you loose your low down torque and add lag... swings and roundabouts

Mr Vindaloo - you're last statement is pretty much spot on. This is why many in the 200+ club have torque at a not so flattering 330-370 lb/ft, but it hits higher up in the rev range, and is held for longer. I'm hoping when my new head/injectors are fitted, I will have a similar tune again. All I want low down is enough to just keep going at a speed. I find mine now at 1500rpm does this OK, but if I want to actually accelerate it needs knocking down a cog (or 2 for very quick )

High torque, high revving, high BHP. All the characteristics of a highly tuned TDI (in my opinion) My torque does tail off, but by the time you reach 3500rpm anyway - It's the BHP which is producing the power really. Same with any diesel I reckon.

one word. twin turbo. if only .......

Isn't "twin turbo" two words?

one word. twin turbo. if only .......

Go onto TDICLUB, look for Diesel Des's thread about compound turbo-charging.

ISTR he hasn't managed to get it all together and mapped yet.

J.

wagons have been twin turbo compounding for years,can't understand why no one has a fully working car variant yet

I've nearly posted replies several times, only to sit back and think "what exactly am I going on about" or "that sounds too critical". ho-hum.

I keep second guessing myself. I have 2 modes of driving my car. Putter along with the traffic and hopefully use CC. And vroom mode where I want to use the power. There is actually, a third mode, which is making progress without flooring it.

But.. the engine seems to produce the smoothest power starting from say 2.3K revs, it revs through to 4K quite readily. Though I wouldn't call it grumpy or knackered, it's certainly more prone to vibration trying to perform at lower revs.

I'll definitely be looking to extend my car's performance. However, there are 2 ways it can go....

1) Go for 200BHP+ on a mild VNT17B hybrid, emphasising driveability, economy and seamless delivery.

2) Go for more. Which I think makes the car into two distinct beasts.

I think the 200BHP version can be achieved with a standard clutch and possibly, a standard intercooler! Though that's reading between the lines of ukmkivs threads and the Golf has a better i/c as standard.

The "more" version will definitely require quite a lot of extra changes. Most of which have been voiced on these forums and tuners' pages.

J.

wagons have been twin turbo compounding for years,can't understand why no one has a fully working car variant yet

there is the 3.5 twin turbo bmw diesel lump, very quick!

A diesel will always tail off at higher revs anyway: there's a limit how fast the fuel will burn, and that's slower with diesel.

I think twin turbos will struggle due to the VNT thing. Not convinced any other twin turbo setup from other marques is also VNT, but I'd be interested to know if they've managed it? I don't what turbos dieseldes is using on TDIclub but I follow the thread every time it gets bumped. Some of the yanks to push their TDIs quite far, but they're not usually PD engines.

Isn't that what a skillfully done custom remap will give?

Thats the whole point of it

This is as about as good as I have seen with just a remap

I think twin turbos will struggle due to the VNT thing. Not convinced any other twin turbo setup from other marques is also VNT, but I'd be interested to know if they've managed it? I don't what turbos dieseldes is using on TDIclub but I follow the thread every time it gets bumped. Some of the yanks to push their TDIs quite far, but they're not usually PD engines.

ISTR a VNT15 and a Holset "big thing".

Read a lot of the American stuff.... Not really understood a lot of it. Lift pumps and 10/11/12mm plungers on injection pumps.... Maybe I started reading too old....

J.

Do we really need much more torque at lower RPMs (say 2K-2.4K) than can be extracted at the moment? Shouldn't we try for a modest gain in torque but held over a bigger RPM range. Say, allow the unit to rev at least to 4.5-5K whilst holding as flat a torque line as possible.

J.

Angel Tuning