Tsi Boost Pressures??

[Creniac]

Does anyone know what sort of boost pressures the 1.4 litre Tsi motors are gulping from the charger and through to turbo transition??

[POLARBEAR666]

My MAP goes up to 35psi max sometimes.

Mostly it is 10-18 at low speeds and 20+ if you have any boot in it at all.

Usually 29-30psi when your car is seeing 80% throttle or more.

It is basically a load of boost.

The only areas that could get some more boost is the mid range which is where I think the aftermarket tunes are picking up nice torque. Just stopping the ecu from venting so much excess boost would increase torque a lot in the places where you hear the BOV going constantly.

Notice my boost level at 2000 odd.

[Creniac]

Polar bear, where did you get your MAP from???

[POLARBEAR666]

it is from the sensor that is attached to the manifold. The boost/temp combination sensor there.

IT is the main one that the ECU relies on.

The scangauge2 just reads from the OBD2 output under the dash. plugs in like a dealer diagnostic tool and reads all the info in real time.

Very handy and only $200 bucks. Cheaper than a boost gauge and 20x as good. It can display any ecu readouts that are major ones. oxygen, air temp, kph, water temp, L/hour, L/100km, tank to empty, total L used. Used on trip etc etc etc etc.

[idaho]

My MAP goes up to 35psi max sometimes.

Mostly it is 10-18 at low speeds and 20+ if you have any boot in it at all.

Usually 29-30psi when your car is seeing 80% throttle or more.

It is basically a load of boost....

I looked at that and thought the same thing but then realised that it says MAP which is Manifold ABSOLUTE Pressure, not boost (Gauge) pressure. And as atmospheric pressure is about 14.5 lb at sea level that means the maximum gauge pressure boost is about 15 lb if the MAP is displaying 30. Can you set it to display in kpa or bar?

[BarneyBoy]

Factory says 2.5 bar for the supercharger, and 1.3 bar for the turbo.

1.8 bar is available just off idle, as the supercharger takes just 40 milliseconds to begin charging at low revs. Even at higher engine speeds it is often called on to aid the turbocharger's activation, which improves overtaking response.

BTW the crankcase is grey cast iron to withstand pressures of 120 bar and 21.7 bar over extended periods. That's WHY it's cast iron and not alloy - all those folks who reckon the TSI is a hand grenade please take note: VW have engineered this engine very thoroughly. Over 250 prototype engines successfully completed the equivalent of 300,000 km in endurance runs.

And while we're on pressures, the injector pressure is a quite high 150 bar and it's this that allowed a fairly high (for a supercharged engine) compression ratio of 10:1.

[Creniac]

Thanks for the info Barney...... interesting figures.... my MY09 Jetta Tsi is certainly fun to drive, as you mentioned to all the folk who think the engine is a grenade!...... I agree with you, why would VW release an unproven engine doomed to fail and tarnish their already strong reputation. It's awesome off the mark, as an RX8 driver found out the other day.....

[POLARBEAR666]

I looked at that and thought the same thing but then realised that it says MAP which is Manifold ABSOLUTE Pressure, not boost (Gauge) pressure. And as atmospheric pressure is about 14.5 lb at sea level that means the maximum gauge pressure boost is about 15 lb if the MAP is displaying 30. Can you set it to display in kpa or bar?

I have now followed the instructions on the X Gauge setup for my Scanguage2. This lets me program new gauge readouts. One of the new ones is corrected Boost which allows you to enter a specific atmospheric pressure to be deducted from whatever the MAP is outputting. This then displays traditional BOOST like a normal gauge.

I will report back with results.

I was under the impression though, that the MAP output from the eCU was already deducting atmospheric pressure because 30-35psi matches the 2.5bar maximum talked about in the manuals etc.

[GTom]

BTW the crankcase is grey cast iron to withstand pressures of 120 bar and 21.7 bar over extended periods. That's WHY it's cast iron and not alloy

The problem with cast iron is that once it reaches UTS it fails the upside is can handled a large amount of stress... VW say the engine will basically be OK to 300,000km (that's around 20 years worth if driving 15k a year, more than enough....)

Wouldn't mind getting mine to 999,999km...... common for Falcon TAXI (which is unbelievable by the way drivers drive these things!)

[tdi guy]

all those folks who reckon the TSI is a hand grenade please take note: VW have engineered this engine very thoroughly. Over 250 prototype engines successfully completed the equivalent of 300,000 km in endurance runs.

Having said all that, when UK car magazine drove a TSI as their long term test, I think it blew at a track day. Can't recall whether it was still standard or had been 'tweaked'. I will check.

TG

[tinto]

Was that Car Magazine?
They blew a turbo that (upon inspection) had a manufacturing defect.
Isolated/random case of a 3rd party supplied part IMO.
Just unlucky for VW and the (apparently) anxious/doubting folks amongst the TSI owners that it was a media car.

[tdi guy]

Was that Car Magazine?
They blew a turbo that (upon inspection) had a manufacturing defect.
Isolated/random case of a 3rd party supplied part IMO.
Just unlucky for VW and the (apparently) anxious/doubting folks amongst the TSI owners that it was a media car.

Thats sounds right (I can't find the article on their web site, only reader comments about it). And I have a TSI and intend to keep it for many years.

I'm not aware how common these types of manufacturing faults are (I've been quite lucky with my cars), and would also be staggered if VW chose to release a product that they were not comfortable to mass market.

I do wonder however if it is prudent to tweak them, given VW has chosen to detune the engine (admittedly to accommodate the 7 speed DSG).

TG

[Creniac]

One thing I would like to know is how much torque the 7 Speed DSG can really handle????? usually there is a factor of safety in place during the design stage..... I wonder??

[POLARBEAR666]

Generally, if you take something that has 6 speeds and make it seven speeds without making the gearbox physically larger, you are going to make it weaker.

Unless they used better quality metal or a special stronger design, more cogs = smaller cogs.

That is why the hardcore drag racers in subaru's and GTR's and such go for a DOG 4 speed box in a box built for 5 or 6 speeds. Each gear becomes MASSIVE and strong.

[BarneyBoy]

One thing I would like to know is how much torque the 7 Speed DSG can really handle????? usually there is a factor of safety in place during the design stage..... I wonder??

You're right - the 7 speed can handle up to 250Nm, the 6 speed 350Nm.
Which is why the 7 speed is not available on the 147kW Jetta (280Nm) or the 103TDI (320Nm) and only on the 118TSI (240Nm).