VP Racing Fuels - Motorsport 103

[Emre]

How much ignition...i ask because i want to start running crappy std unleaded instead of BP Ultimate/Optimax etc.  Wondering how much ignition i should take out to allow for the lesser grade fuel?

We stuck as much as 5 degrees and extra boost on a batch of decent fuel mixed with Synergy.

I don't know whether what you are suggetsing is a smart idea though. The difference of 9 cents a litre is about $5 per tank, which is less than the price of a souvlaki.

I don't even run that crappy 91 RON thing they pass as fuel in my Astra.

[ricknismo]

So with a standard computer, stepping up from pump fuel to say the 103 (andra ok) and leaving the car in exactly the same spec, couldn't a bit more boost be used and therefore gains achieved.

I recently watched 'motoractive' dvd and he simply put in the fuel and upped the boost to gain power, do you think they were hiding the timing adjustment process???

[Emre]

If you don't adjust your tune to suit the chosen fuel, you are not getting the optimum gains. This could be considered as a waste of money by some, especially when said fuels cost a considerable amount per litre.

If you have a stock vehicle, a better bet would be to spent money on some permanent gains rather than using an expensive fuel as a temporary gain.

If you have a somewhat modified vehicle, consider whether upping the boost will effect other things like : fuel flow, turbo efficiency etc.

If you have all bases covered, than decent fuel will yield excellent results with a quick change to some parameters.

You don't need an aftermarket ECU to adjust timing. Base timing can be controlled and extra timing can be added with the crank angle sensor. He may have used this method, or he may not have; the question is : what exactly did he achieve at what cost...?

[ricknismo]

I watched it again, he simply siphons motorsport 103 into the tank and goes from 1 bar to 1.2 to achieve a gain of 208kw@ all 4 to 249kw @ all 4 (33 GTR)

[Emre]

40 awkw gain just by raising the boost from 1 bar to 1.2 bar sounds a bit excessive.

Here is the thing : Fuel alone does not give you any additional power, it allows you to tune the car more agressively to extract more power. Stock ECU doesn't recognise the higher octane and advance the timing; from what you watched and described he is only gaining this power from increasing the boost by 0.2 bar.

Why does he need 103 octane to run 1.2 bar...? I ran small busts of 1.2 bar on pump fuel without any signs of detonation. A small amount of higher octane can be used for safety, that is all.

Why does he need 103 octane to get 249 awkw...? What happens when he runs out of $300 per tank fuel...? He is down to 208 awkw. By spending the money on cam gears, he could get that power permanently at the same boost on pump fuel. (assuming he has a decent exhaust)

At that point, if you are still chasing more power, decent fuel still couldn't help you much. It would allow you to run more timing, but more boost from stock turbos wouldn't be advisable as you are already stressing the little buggers. That's when you upgrade the ECU, turbos and fuel system to get up to 300+ rwkw mark, still on pump fuel. Higher octane fuel would be more beneficial at this point, as you are able to flow more air with an easier control of the timing and fuelling.

Back to your original question after all this rambling.

So with a standard computer, stepping up from pump fuel to say the 103 (andra ok) and leaving the car in exactly the same spec, couldn't a bit more boost be used and therefore gains achieved.

Sure, some gains can be had.

[Emre]

It has been my experiecne that with an oxygenated fuel, particularly one with a high specific gravity, I also need to take some fuel out of it as well.  It is the weight of the fuel that matters, not the volume. The ecu operates by varying the volume, so to allow for the extra weight I have take out some volume to get back to the correct weight.

Hope that makes sense:cheers:

I've just noticed this post now, when re-reading the whole thread SK.

Yes, we leaned it out for more gains, but that was done by % to the whole map which resets when you turn the ignition off.

I was trying to say that, tuning by the individual cells wasn't necessary.

[jezzrrr]

It has been my experiecne that with an oxygenated fuel, particularly one with a high specific gravity, I also need to take some fuel out of it as well.  It is the weight of the fuel that matters, not the volume. The ecu operates by varying the volume, so to allow for the extra weight I have take out some volume to get back to the correct weight.

Hope that makes sense:cheers:

Ive run VP 103 in my R34 and it makes a BIG difference, +5 degres and a heap more torque.

SK, out of interest, how much would you lean the AFR out when running this type of fuel ?

[Sydneykid]

Ive run VP 103 in my R34 and it makes a BIG difference, +5 degres and a heap more torque.

SK, out of interest, how much would you lean the AFR out when running this type of fuel ?

More timing plus more boost (without detonation) is the big advantage.

I haven't retuned a car for VP103 so I have no experience there. With TurboMax we take out as much as 10 to 15% to maximise the power. But it is very trickyto balance the detonation versus power A/F ratios. Certainly not something I would recommend is done by guessing a single reduction %, stick it on the dyno and fully map it. Otherwise you are waisting some of your money on the fuel.