Super Unleaded provides zero benefits for stock TSI engines

[Orville]

For me the VRS engine seems largely unaffected by fuel and weather conditions.

 

My old Subaru's (UK Turbo and import STI IV) both used to LOVE the cold weather and HATE hot days. You could really feel a difference when planting the right foot on a cold winters morning, it really did seem to pull harder for much longer. The same applied for fuel, especially the STI which came alive with >100 RON. Even though I (eventually) had it remapped to run on 95RON, it felt like a different beast on 100+ (Super + Octane booster). Within these cars the difference was noticeable ON THE ROAD.

 

Perhaps there is some performance difference with the VRS, but if so it is so small as to be negligible and I cannot feel it. I believe that the VRS TSI works so far within safe tolerance range, that weather and 95RON+ fuels have little affect on the road. This is probably why APR, Revo & Co can extract >300bhp out of a 95RON ECU remap.

Edited 11 March, 2015 by Orville

[pipsyp]

The Golf 7R is recommended to run on Super unleaded

I'll give you that one 999Pooch. I am sure however the TSI 220 is recommended for 95 RON use. Sure you "might" notice some performance increase with 97+ fuel but clearly that engine is optimised for use with 95 RON fuel.

I guess to make 300hp reliably the R engine needs 98+. A bit rubbish in the UK where alot of super is 97 RON..somewhat limited to Shell V Power or Tesco otherwise.

In UAE the Mk7 R is detuned to 280ps....Im guessing partly for climate but maybe also for fuel quality?

[Mallettsmallett]

This is a bit of a thread from the dead but has anyone got any links to dyno tests for the average % output loss on a car that's set to use 97 Ron using 95. I've just tried using 95 in my tsi vrs and the loss of torque is very aparrent.

[Orville]

I don't think any 95 RON vs Super figures have been published for stock GTI 7 / VRS III TSI engines. The closest I can find are official APR figures for their Stage 1 tune. Running 95 RON the engine produces 306bhp / 371 ft/lbs vs 316bhp / 381 ft/lbs for 98 RON. That's +10bhp and +10 ft/lbs (~3% gains) for a very highly tuned engine. I guess the difference will be far less on stock engines.

APR results link below.

http://www.goapr.co.uk/products/ecu_upgrade_20tsi_gen3_mqb.html

[Richf]

My TSI 220 clearly states "MIN 95 - Super unleaded" inside the fuel cap , I take that to mean that Super unleaded is recommended but that you must use at least 95 octane as covered on p189 on the manual, much like the Fabia VRS which had 98/(95) inside the filler cap . If it was designed to run on 95 unleaded why would they mention super unleaded?  

 

Having ran cars requiring super unleaded for many years and mapped them, on turbo charged engines the mid range ie peak torque area is usually where the difference is felt firstly since the "butt dyno" can only really detect torque rather than hp and secondly thats the area where peak load is and therefore the most likely area to detect knock and have timing and/or boost limited or fuel added. 

 

IF you dont use full throttle and therefore full boost then I suspect you would notice little difference however if you do run full throttle on 95 and the engine does feel the need to pull timing then you may find the car is less economical on 95 due to the timing creating a less complete burn

 

The 350z with around 280hp will lose about 30hp if mapped to run on 95 instead of the usual 98 , this is about the same as the Mitsubishi Evo 2.0 turbo engine so i would think losses would be in the region of 10% although its better to map a car to run lower octane than just run the lower octane and expect the ecu to adjust as they can over compensate   

[StevenB]

From my knowledge it's about what the manufaturer has decided to allow for ignition advance following knock detection.

 

I have a classic Scoob and that is night and day different between 95 and 98/99 after some learning by the ECU after a reset. I remember from a car mag test that VAG are notoriously stingy on the allowance of ingnition advance so would explain the lack of difference seen maybe ?

 

Steve.

[philhoward]

Not done enough miles on a "Stock" TSI engine but both twincharger 1.4's I ran (Scirocco and Fabia vRS) were both quicker and more economical to boot.  I believe the wording used for the Fabia vRS is "reduced performance on 95RON" - also read as "optimised for 98RON".  The Scirocco was "minimum 95RON", but certainly went a lot better on Super-juice - more than enough to offset the extra cost (company car, so they needed financial justification for using more expensive fuel).  The Fabia wasn't as quick on 95 - and like the Scirocco, there was a 10% or so difference in mpg returns.