Fuel economy problems...any suggestions appreciated

[brad]

Are there no 21st century equivalents to the 1950's Redex which I still recall my father and his contemporaries either adding to the tank or squirting into the carburettors? Was a pretty instant partial de coke as I recall. Never quite the same as lifting the head and cleaning manually so suppose in many ways nothing has changed. Maybe these 'old' solutions have no place with modern EFI and ECU controlled engines?

yes, you can still buy equivalents.

No point adding to the tank though as it's direct injection.

I've posted the various methods many times on this forum.

There was no sign of any gunk on the cat when I had the DP off (twice). It's right on the outlet of the turbo - any gunk turns to ash due to the heat and passes through.

[Gerrycan]

G'day Gerry,

I've got the new 1.8T engine.

My suspicions were correct. It does NOT like Shell V-Power. I've filled up on Ultimate 98 and it's fine again. Usually run Mobil 98, again, without fault.



MY13 Kluger KX-S AWD / MY16 Polo GTI

I'm really surprised the type of petrol made so much difference on your 1.8tsi.
In relative terms your engine is in a low state of tune compared to say my 1.4tsi and the 2.0tsi in the RS so I would have thought it would be more tolerant.
My engine shows no obvious performance difference between 95 or 98 Octane so I tend to use the 95 Octane but others swear by and would not consider using anything but the best.
You could also have got a bad batch of fuel, it does happen. A friend's brand new Discovery 4 diesel engine was ruined by contaminated fuel in one Darwin service station as were at least 30 others by his account.
Pleased for you that it is resolved so easily though.

When I say your 1.8 in a relatively low tune state that is because it (officially) produces the same torque as the 1.4, albeit over a larger rev range, yet it has the same sophisticated manifold/direct injection fitted to the 2.0 engine. Scares me to think what your 1.8 would do if were chipped.

[Martin]

There was no sign of any gunk on the cat when I had the DP off (twice). It's right on the outlet of the turbo - any gunk turns to ash due to the heat and passes through.

Good to know, thanking you

[brad]

Good to know, thanking you

You've got an APR DP. The cat is further back near where the #2 (600cell) cat is on the OEM DP & 200 cells.

Gerry
The torque is artificially limited but I get your point. What's the kw/cc & Nm/cc ratios for those 3 engine sizes?

[Lucas_R]

Good to know, thanking you

I second this - removed the stock DP off my Mk6 GTI at approx 60,000km and the cats looked good as new....very restrictive in their design but not blocked etc

[Martin]

I second this - removed the stock DP off my Mk6 GTI at approx 60,000km and the cats looked good as new....very restrictive in their design but not blocked etc

It's not a mileage issue - Brad is saying if you clean out your own inlet any crap is burnt up prior to reaching the cat

[Gerrycan]

Relative states of tune:
1.4tsi - 74kw/litre, 179nm/litre. mean pressure 21.1 bars
1.8tsi - 74 kW/Litre, 139nm/Litre, mean pressure17.4 bars
2.0tsi - 82 kw/Litre, 176nm/Litre, mean pressure 22 bars

[MickeyB]

Any gains to be made by following Subaru's method of "UPPER ENGINE CLEAN"?

I'm noticing my MY16 POLO GTI get a bit 'cranky' during cold high idle and in hot traffic, albeit only 8500kms.

Could be less amicable fuel that I've read about....that is, they don't live VPower


MY13 Kluger KX-S AWD / MY16 Polo GTI

I've used the upper engine clean on a couple of my cars: it's pretty nasty stuff: requires gloves, preferably not breathing the fines and it STINKS when you run the engine.

As far as results go, my mech swears by it, but if I'm honest, I never really noticed it having much affect on either engine running or fuel efficiency on my vehicles.

For reference, I tried it on a jap 4 cyl turbo (Toyota Caldina), atmo V6 (V35 Skyline), and BMW V8 (540i). All cars were well services, around 6-10 years old, and had between 60,000 and 110,000km on the clock.

I paid nothing for the process, but in my case can't say whether it did anything beneficial.


No battle plan ever survives contact with the enemy

[woofy]

I had issues like that years ago and turned out the apprentice hadn't connected the gauge properly underneath the rear seat when replacing the fuel filter.