Pump Vs Race (or C16)

[rtune]

Given a fairly optimal tune on pump gas, what + does a tune for C16 give - as a percentage on base tune?

assume twins or a single, doesn't really matter, any real world experiences? I know from a search

that dirtgarage dyno'd at 400 something on pump @ 28psi and 460 something on race @ 34psi.

So that would be roughly a 15% improvement. It wasn't clear whether that was two optimal maps

or just gained from upping the boost, though..

I'd also love to know if that is 15% all through the rev range, or just at the top end..

Since power-fc is so common, with its single map, perhaps there aren't many documented examples?

but maybe cars with Motecs, Vipecs know the answer..

[R31Nismoid]

Every car, every setup is different.

There is no set improvement. Some people see massive gains due to restrictions and also the flip side of better flow

Some people less because they can already run good timing numbers

Nothing set IMO. Take it on its own merit.

[rtune]

Every car, every setup is different.

There is no set improvement. Some people see massive gains due to restrictions and also the flip side of better flow

Some people less because they can already run good timing numbers

Nothing set IMO. Take it on its own merit.

thanks,

but that can be the answer to almost every question here that has the word "power" in it.

Was hoping for some real world examples if there are no rules, or even rules of thumb..

nobody (with time to post) runs two maps and two fuels?

[rev210]

the combustion characteristics of the race fuels are obviously quite different ( in a good way) and therefore not only does this effect everything in a tune , from cam timing to AFR but, also if you intend running a car on race gas then you can do allot to the way the engine is built for optimisation or the reverse if you are running on a fuel the build was not intended for.

Hence the comments along the line of 'how long is a peice of string'.

If you wanted a guide there really is only one for motors of the same type , spec and build assuming the same tune. Sounds pretty useless doesn't it.

However, as a rule 'race fuel' will always offer some benificial gains over BP regular etc.

Some street based cars use it due to it's nicer burn characteristics and soley run it to protect the motor in races or the occasional motorsport event. It is not uncommon for there to be little or no power gain chased by these situations. The fuel is consistantly good unlike pump fuel experiences and offers the margin of safety for extreeme events.

My mates and I used to fuel up with Av-gas for a trip to the drags (prior to my skyline days). We found it better for the day at the drags for things like vapour lock on a hot day and also to help things like when jetting for temp changes during the meet it was easier to get it right. Although the gear we play with is high tech the race fuels offer a more forgiving margin.

Hope that helps.

Edited January 21, 2009 by rev210

[rtune]

the combustion characteristics of the race fuels are obviously quite different ( in a good way) and therefore not only does this effect everything in a tune , from cam timing to AFR but, also if you intend running a car on race gas then you can do allot to the way the engine is built for optimisation or the reverse if you are running on a fuel the build was not intended for.

Hence the comments along the line of 'how long is a peice of string'.

If you wanted a guide there really is only one for motors of the same type , spec and build assuming the same tune. Sounds pretty useless doesn't it.

However, as a rule 'race fuel' will always offer some benificial gains over BP regular etc.

Some street based cars use it due to it's nicer burn characteristics and soley run it to protect the motor in races or the occasional motorsport event. It is not uncommon for there to be little or no power gain chased by these situations. The fuel is consistantly good unlike pump fuel experiences and offers the margin of safety for extreeme events.

My mates and I used to fuel up with Av-gas for a trip to the drags (prior to my skyline days). We found it better for the day at the drags for things like vapour lock on a hot day and also to help things like when jetting for temp changes during the meet it was easier to get it right. Although the gear we play with is high tech the race fuels offer a more forgiving margin.

Hope that helps.

It helps a bit.

But I was thinking more along the lines of feedback from someone who runs or did run an ECU with two maps and

(obviously) the same engine. What did they dyno on the pump gas map and what did they dyno on the C16 map.

From reading experiences outside skyline/rb land, but still from forced induction motors, going from pump to

C16 allowed quite a thumping increase in torque simply obtained by advancing the timing and increasing the boost

and running leaner.. three things some ECUs can do all at once without any change to engine setup.

But it wasn't clear from searching whether there are RB26 engines have reported the same result.

Another way of looking at the question: if australian servos switched to japanese pump gas - which isn't anything

like C16 - you guys would be off to the tuner to get remapped, yes?

I wonder what % gain would be typical. 1%? 5%? 10%?

[R31Nismoid]

^^ much better words than i put in

I made over 100rwkw more with just 6psi when i used 104 vs pulp, but as i said, i had a restriction so the better fuel negated that massively and an extra +8 degree of global timing. BUt not everyone will see such gains and so on

[2rismo]

^^ much better words than i put in

I made over 100rwkw more with just 6psi when i used 104 vs pulp, but as i said, i had a restriction so the better fuel negated that massively and an extra +8 degree of global timing. BUt not everyone will see such gains and so on

The better fuel may have negated the restriction more than you think if the restriction was in the exhaust/exhaust housing.

[R31Nismoid]

Thats exactly where it was - and i did say massively negated... how much bigger does it need to be? we knew the fuel would do wonders

[2rismo]

I knew what you meant - maybe we mean the same thing

I was just saying that the tune-up on race fuel with the extra timing would likely have relieved some of the back-pressure issues you had.

Like I said, we're probably saying the same thing...

[ahh 33 s2]

6 ron, 6 psi and 8 degrees = 100kw

wow thats an impressive gain

[rtune]

6 ron, 6 psi and 8 degrees = 100kw

wow thats an impressive gain

yeah! even more so if the start was 200 and the end was 300 !

[R31Nismoid]

It was 270rwkw and a choked 270rwkw at that, and this was on 17psi... bumped to 24 (ok 7psi, my brain isnt good with math)

This was all on the big 600hp GT30, not the 500/550 littler ones so there was other issues with comp surge and so on to deal with.

On the pulp tune anymore and it would get agro with detonation and so on, there were a few factors involved/fixed/relieved other than just a fuel/timing change as Adrian has said in a better way than i did

The figure sounds about right for what a 600hp turbo on fuel should do seeing as though the GT35's on PULP get similar numbers

So ye Adrian - we are thinking the same thing

[Swiper the Fox]

It all depends on the efficiency of the engine/set-up...the more efficient the engine the less the gain as it burns the fuel better and consequently transfer's its energy into power better. For example my old set-up (the example you gave) used to see over 50-60awkw gain (best back to back run we did was 70awkw)...now its only about 20-30awkw. A stock or near stock set-up may see 85-95awkw gain (Ash's car is a perfect example of ths).

hope these real world example's are of help.

Edited January 21, 2009 by DiRTgarage

[rtune]

It all depends on the efficiency of the engine/set-up...the more efficient the engine the less the gain as it burns the fuel better and consequently transfer's its energy into power better. For example my old set-up (the example you gave) used to see over 50-60awkw gain (best back to back run we did was 70awkw)...now its only about 20-30awkw. A stock or near stock set-up may see 85-95awkw gain (Ash's car is a perfect example of ths).

hope these real world example's are of help.

that is interesting.. thanks. So what mod do you most attribute the reduced gap to, for your particular engine evolution?

I assume both outputs went up, but the pulp went up more (thus closing the gap)?

[rob82]

It all depends on the efficiency of the engine/set-up...the more efficient the engine the less the gain as it burns the fuel better and consequently transfer's its energy into power better. For example my old set-up (the example you gave) used to see over 50-60awkw gain (best back to back run we did was 70awkw)...now its only about 20-30awkw. A stock or near stock set-up may see 85-95awkw gain (Ash's car is a perfect example of ths).

hope these real world example's are of help.

I take it your only talking a topend power figure when your refering to engine efficency. Better fuels should always make more horsepower and if they dont then its time to make the engine more dynamic.

[Swiper the Fox]

that is interesting.. thanks. So what mod do you most attribute the reduced gap to, for your particular engine evolution?

I assume both outputs went up, but the pulp went up more (thus closing the gap)?

the head

[R31Nismoid]

I take it your only talking a topend power figure when your refering to engine efficency. Better fuels should always make more horsepower and if they dont then its time to make the engine more dynamic.

Well midrange is also massively improved with the added timing and so on, boost sooner etc

the difference was night/day with my car and not just because of the 100kw... without the +8 timing it was still amazing with just the extra boost... the timing just made it silly