Hi everyone,

I haven't posted on Briskoda meaningfully in a long time. I used to be very active in the Superb sub-forums over the ~15 years I've had Škodas. I've read with interest the many MPG threads on here over those years, and always wondered about my own cars, too. So, I decided to actually put the matter to bed. In my previous Superb (2.0 TSI 220ps DSG) I felt 99 RON gave a power and MPG edge over 95 RON fuel. The BMW X2 20i xDrive that followed it, definitely so!

When it came to my 2024 Mk I Kodiaq 1.5 TSI EVO ACT DPCA 150ps DSG SE-L Executive (7 seats, 19" wheels), though? I wasn't so sure. The car 'felt' sharper, but MPG didn't seem much different. I'd never actually tested it, just gone off 'feel' and transient leg/tank MPGs.

I decided to log every fill and every single journey(!) over 11 tanks of fuel and 4,000 plus driven miles. I have tested 95 RON, 97 RON, 98 RON (blended) and 99 RON — as well as various additives like Miller's Petrol Power ECOMAX (no difference), Redex Petrol System Cleaner (smoother drive, mild MPG uplift), Archoil AR6900-P Max (large MPG uplift, dull/flat drive), Oilsyn Petrol Power DNA (strong PEA detergent, lubricious — raised MPG floors but introduced a lot of ECU adaptation and 'unsettled' feel, somewhat capped MPG ceilings).

Then, finally, I came across Oilsyn Hybrogen Road.

Hybrogen is an interesting one, and as soon as I read about it I knew I just had to test it. It is the only additive I've come across that clearly advertises a positive MPG gain. That is, dosed at only 1:3000 (1ml per 3 litres of fuel) it claims to increase torque, power and MPG above and beyond an identical factory-clean engine when used in either petrol or diesel road fuels. Not 'cleans back to factory and restores lost MPG', but actually physically raises MPG, period. It's not a detergent (directly), nor does it affect octane or lubricity. It's a nano-colloid which basically acts as a dispersant, surfactant and combustion modifier. It removes water from fuel (eg ethanol blends), cleans the fuel system, and — most importantly — aggressively homogenises the hydrocarbons in fuel (petrol or diesel) for a consistent and clean burn. That, they say, results in a higher MPG while increasing power and torque across the whole area under the curve.

Sounds like woo?...

Long story short, my average MPGs (mostly short, urban journeys from cold tested across pair-matched routes and drive cycles) ended up at:

Fuel mix	Tank average MPG	Uplift over baseline
Unadditised 95 RON	~30.0	-
Unadditised 99 RON	~30	-
95 RON + Hybrogen	37.4	24.67 %
99 RON + Hybrogen	34.5	15 %
Hybrogen long term average	36.0	20 %

I should add that the 95 RON + Hybrogen tank includes a return trip from Devon to Liverpool. As such, the 99 RON + Hybrogen tank (~35 mpg) and its 15% uplift is more representative overall of the realistic tank average of this fuel/additive mix day-to-day. For example, if you read the full dataset, tank 7 (95 RON + Hybrogen) closed at 35.2 mpg and didn't include a longer motorway leg. However, the long term average (30 -> 36 MPG) includes a fully representative mix of driving in both cases, and the overall average increase of 20% over unadditised baseline stands validated.

Fuel mix	Urban MPG	Pence per mile
Unadditised 99 RON	~30	24.0
Unadditised 95 RON	~30	22.7
99 RON + Hybrogen	34.5	20.8
95 RON + Hybrogen	37.4	17.9

I tested by running a tank of X mix first, then took the uplift measurement from the second subsequent tank of the same octane/additive mix, to allow time for ECU adaptation and fuel trims to settle etc. Interestingly, withdrawing Hybrogen (diluting it out of efficacy) caused MPG to regress back to the same ~30 MPG baseline tank average, restoring back to mid-30s MPG once reintroduced on subsequent tanks.

I also ran paired matched-route analysis and various other statistical tests on the (large!) dataset, and the winning fuel for this engine in my mixed driving cycle is unequivocally 95 RON + Hybrogen. There was no benefit in 97–99 RON fuels at all (this engine is not knock-limited in regular driving), and in fact they were harder to extract good economy from because the higher octane shortened the torque response vs throttle travel, resulting in a 'hair trigger' and more transient fuelling events.

While the numbers might seem outlandishly large, please remember that (1) independent testing — including university testing — on the Oilsyn website shows similar numbers across various engines and regimes, and (2) my uplift came unambiguously from both the additive's direct effect on fuel, and the secondary effects such as the broader torque curve allowing gentler throttle at cruising speed, prolonged ACT engagement etc. Combined, the uplift is what you see above, and it's repeatable.

The full (mildly anonymised) dataset and all my notes throughout can be read on Github as a Gist if you're interested.

Gist

Škoda Kodiaq 1.5 TSI fuel economy: Oilsyn Hybrogen additi...

Škoda Kodiaq 1.5 TSI fuel economy: Oilsyn Hybrogen additive test - fuel-test-anonymised.md

TL,DR: If your car says Min. 95 RON then — unless you're lapping the Nurburgring at three figures and ten tenths —  just save money and use 95 RON (and Hybrogen!). No matter the scenario, from urban short hops from cold, through fully-loaded fast ~300 mile motorway runs up Devonshire hills with 7 people on board while pulling a roof box and hundreds of KG of luggage, 95 RON worked out both most economical (MPG) and cheapest at the pump.

Please note I made no money from this testing, I wasn't paid for it, I'm unrelated to Oilsyn or any other fuel additive seller, and I'm just a long-term member here who decided to answer my own question as best I could. This is what resulted from that! Take from it what you will. Personally, I'd never go without using Hybrogen again. Not only does its modest cost (~1 ppl extra) pay for itself and then some, but the annual savings as detailed in the full report are huge (up to ~£500/year at 10,000 miles of mixed driving). Full fuel costs, pence per mile and other metrics are included in the full report/dataset if you're interested.

Cheers!

Edited 7 May7 May by Rainmaker
Clarified octane vs tank average table results. Tidying up.

Which Brand was the 97 ron minimum and the 99 ron minimum you were using as it is not all the same formulation for 99 ron E5 around the UK and it can have from 0-5% Bio Ethanol. Pence per mile is not meaning much if you are not saying if you use / buy Supermarket E10 95 Ron or the Branded higher cost or the likes of Tesco Momentum 99 or Sainsburys 97 E5 or ESSO, Shell etc at maybe 6 or more pence a litre extra. *** Late October til March and maybe later than March this year is a different formulation of Gasoline sold in the UK. Less Hygroscopic.*** A bottle is a bit less than a gallon of petrol was before the price hikes, so if it gives you more miles extra than 4 litres of petrol purchased at current prices then fair enough. say 8 miles from a litre of 95 ron.

388380a097b04fe693a8c27db8bb4974 (1) (2).pdf 6ca06d648b9541e78fa838fece4a1a23 (1) (2).pdf

Edited 7 May7 May by Evolution13

4 hours ago, Rainmaker said:

Sounds like woo?...

Sure does.

Changing the effective energy available in the fuel that much stretches credence well beyond breaking point.

Something else going on here, probably driver behaviour, since the testing wasn't blind.

How many snakes are in it per litre?

It is really amazing (not!) that Fuel Producers do not use these additives in their fuels & maybe just charge an additional pence or 3.

unavailable outside UK.

7 hours ago, Evolution13 said:

Which Brand was the 97 ron minimum and the 99 ron minimum you were using as it is not all the same formulation for 99 ron E5 around the UK and it can have from 0-5% Bio Ethanol. Pence per mile is not meaning much if you are not saying if you use / buy Supermarket E10 95 Ron or the Branded higher cost or the likes of Tesco Momentum 99 or Sainsburys 97 E5 or ESSO, Shell etc at maybe 6 or more pence a litre extra. *** Late October til March and maybe later than March this year is a different formulation of Gasoline sold in the UK. Less Hygroscopic.*** A bottle is a bit less than a gallon of petrol was before the price hikes, so if it gives you more miles extra than 4 litres of petrol purchased at current prices then fair enough. say 8 miles from a litre of 95 ron.

388380a097b04fe693a8c27db8bb4974 (1) (2).pdf 6ca06d648b9541e78fa838fece4a1a23 (1) (2).pdf

The fill history table is in the dataset I linked (though it needs tidying). It was mostly Costco 99 with a couple of tanks of M99 where practicable.

7 hours ago, Breezy_Pete said:

Sure does.

Changing the effective energy available in the fuel that much stretches credence well beyond breaking point.

Something else going on here, probably driver behaviour, since the testing wasn't blind.

Nobody said it changes effective energy or raises BTU? In fact I specifically suggest that the cleaner, more consistent burn allowed more ACT engagement and less throttle travel, which directly contributed to easier driving and higher overall MPG. If you read the university studies quoted on the tech sheet, the dyno runs show a consistent increase in torque and power across the area under the curve, but especially at the lower end. That makes for much smoother inputs with less transient fuelling events, which correlated to much better economy overall.

5 hours ago, Evolution13 said:

It is really amazing (not!) that Fuel Producers do not use these additives in their fuels & maybe just charge an additional pence or 3.

They do. V-Power is basically polyether amine and inorganic friction modifier, and it's 20ppl more expensive than the cheap stuff. Ditto most other brands. Go actually sell two grades of 95 RON, regular and 'Xtra' (with additive). Or, you can buy a PEA based additive and get the same thing (often with higher effective treat rates ppm) at a fraction of the cost. Same as anything else, really. Unleaded petrol is a fungible good, additives not so much.

Either way, I can be quite confident that anything over 95 RON is wasted in this engine for my duty cycle, which is my point.

5 minutes ago, Rainmaker said:

allowed more ACT engagement and less throttle travel, which directly contributed to easier driving and higher overall MPG

So, different behaviour from the driver, as suggested.

Which University? Link?

Edited 7 May7 May by Breezy_Pete

7 minutes ago, Breezy_Pete said:

So, different behaviour from the driver, as suggested.

Which University? Link?

...which wouldn't have been possible without the increase in power and torque provided by the additive. I already provided the links, you just need to read them. 😂 Queen's University, for example, showed a 12% improvement in economy and a 14% improvement in power.

I'm not selling anything, I just found my data interesting and figured others might, too. It's always funny to share a large dataset and have the immediate response be 'Snake oil!' with no analysis, no null hypothesis, no further testing, no counter data — just a hand wave and off we go (I'm not referring to you directly, I'm speaking generally).

I looked at your github stuff, didn't notice any links. The oilsin brochure doesn't have any references, just mentions.

I won't bother any more, unless you can supply some real evidence.

Real evidence of what? I don't get the dismissive hand-wavy attitude folks have to things like this. I wondered whether 99 RON would give me any further economy benefit over 95 RON, so I tested identical routes over 11 tanks of fuel/~4,000 miles; and found that for my 1.5 TSI, on my driving cycle, with my driving style (police-trained advanced course tutor) that it didn't.

The paired matched-route analysis and deltas are all provided in the dataset, and when I ran analysis (limited by the small sample size) the data was significant to p <0.05, and 95 RON was the overall best fuel for this engine in my use-case. The fact Hybrogen allowed me to extract extra MPG by widening the torque curve and making the torque demand more linear (resulting in more ACT engagement and less transient fuelling events) is a happy side effect, but it wasn't the point of my post.

Even if you disregard the additive completely, since it's a consistent presence one can still compare the octane differences across matched routes. Whether unadditised or not, I have found no consistent uplift in economy on ≥97 RON fuels in this engine, though feel did change materially causing a paradoxical MPG reduction due to less elasticity in the throttle travel vs torque demand on the ECU.

Evidence of the stuff doing anything at all.

Too much history of similar 'revolutionary' shizzle to take claims at face value.

By the way, I have no problem with your dismissal of higher RON benefits on mpg, not actually surprised by that one. RON isn't a measure of energy content.

5 minutes ago, Breezy_Pete said:

Evidence of the stuff doing anything at all.

Too much history of similar 'revolutionary' shizzle to take claims at face value.

By the way, I have no problem with your dismissal of higher RON benefits on mpg, not actually surprised by that one. RON isn't a measure of energy content.

I know, but the forums are littered with folks claiming higher octane gives them more power (it definitely alters feel and torque demand per throttle %) and MPG. While the energy content is similar between grades (depending on BOB/base stock make-up, ethanol percentage and aromatic/olefin content vs oxygenates), the argument/theory is often that the increased knock-resistance allows timing advance to a degree that permits leaner operation and/or better extraction of underlying BTU. On the 2.0 TSI, it certainly can. On the 1.5 TSI, I think my data is pretty definitive.

I don't have any 'evidence' outside of my own data, but I'm not trying to present any. My thread and my testing was about octane in this particular engine. I'm not selling anything, and I don't care either way. I did, however, notice a significant drivability improvement and economy uplift while using Hybrogen, so I commented on it. I also found their other product actively hampered economy, which I also reported.

When I removed Hybrogen mid-test, leg MPG dropped and tank averages drop back to my historic ~30 mpg baseline. With it added back, legs improve again and tank averages rise back to mid-30s MPG despite ambient temperatures and routes remaining consistent. That lines up with Oilsyn's claims, but I don't care to push the issue — I'm not selling the stuff! That's just what I've found (time and again).

@Rainmaker Is the Shell v-Power additives package different from Tesco Momentum 99,s. Greenergy and Royal Dutch Shell import the same base fuels to various Depots then the additives are added? Not the same with all Shell products, or Greenergy for Tesco or Esso. There are E5 Superunleaded on sale at less than the price of E10,s in some retailers. Sainsbury,s E5 97 ron minimum can be 99 ron depending on their supplier at times as can 99 ron min be 100 ron / octane when brought in already mixed from Continental Europe.

Edited 7 May7 May by Evolution13

@Evolution13 That poster is a little outdated. Texaco are 99 RON too these days, with their 'Techron' (at least under US branding) PEA based additive. As for Shell and Greenergy's shared facilities, that's true. Additive wise, Shell have always leant heavily on their PEA ('Nitro+'/nitrogen cleaning) content, though Tesco have been less vocal about their own additive package. Shell have also removed focus from their 'FMT' (friction modifier) recently, though the small print shows it's still present.

As I'm sure you know, Greenergy (controlled by Trafigura, part-owned by Tesco) supply Tesco, Esso and others. I do have historical spec sheets for V-Power and Momentum 99 (the latest data I could find for them), and the differences are pretty stark. M99 had a higher MON than V-Power (which explains why tuners love it), but a lower olefin/aromatics content and higher oxygenate content (more power, better charge cooling but potentially lower MPG). The old Millbrook report showed injectors and cylinders/piston crowns were marginally dirtier on M99 than V-Power, suggesting Tesco may be relying more on older PIBA/PIBSA/PIBSI type additives rather than PEA.

Those other additive types are decent at preventing deposit buildup, but less effective (or ineffective) at removing existing deposits. PEA specifically survives the combustion process, which allows it to remove deposits further up/downstream of the combustion chamber, which is why aftermarket additives with PEA (like Oilsyn Petrol Power DNA, Techron et al.) are so effective, and so many others are basically snake oil with an upper cylinder lubricant.

I linked the Tesco Momentum 99 Formulation back about a decade ago when it was the only company that showed it for the UK. As to TEXACO, the Tesco Express near me sells E5 99 ron TEXACO, but is that correct for all TEXACO Stations that it is TEXACO SUPREME 99 ron that they sell? I do hate how Companies leave up old Websites.

Edited 7 May7 May by Evolution13

PS. I think you need to look at some Tuners vids, they love TESCO MOMENTUM 99 but as for Shell V-Power maybe you can link one that recommends that. I have been Dynoing cars for years and sprinted and did hill climbs, for me and others, Tesco Momentum 99 in Scotland or Carless Hiperflo 250 @ double the price. No unnecessary additives just purer fuel & the higher octane.

Edited 7 May7 May by Evolution13