Mon Jul 07, 2014 7:03 pm
Mon Jul 07, 2014 8:24 pm
Mon Jul 07, 2014 8:37 pm
Mon Jul 07, 2014 10:47 pm
Tue Jul 08, 2014 12:48 am
Tue Jul 08, 2014 2:30 pm
Tue Jul 08, 2014 6:38 pm
Tue Jul 08, 2014 7:45 pm
Tue Jul 08, 2014 7:54 pm
Tue Jul 08, 2014 8:09 pm
CMS-GT4 wrote:Does the JDM 185 model list the RON requirement on them or in the manual?
Wed Jul 09, 2014 5:39 pm
Mon Jul 14, 2014 4:48 pm
Ok Just to clear things up for you new guys or those who don't know much about the GT4's ECU the problem is the following.
The JDM gt4 base map is set for 100ron fuel, as such it is setup with a very agressive spark advance curve, i.e. as reves rise the ecu adds a hell of a lot of advance.
Now when you stick 95 ron fuel in the fuel is less able to withstand det and as a result det will start sooner than with 100ron fuel. The 3s-gte is what's called a det limited engine. This means that the maximum torque(which is what you map) you can achive on boost is limited by when the engine starts to det. Given the fact that 95 ron fuel starts to det earlier than 100ron fuel a map setup for 100ron fuel has the potential to cause a lot of det when run on 95ron fuel.
Now the flip side to this that some people will arge is that the gt4 ecu has some pretty advanced knock detection and avoidance built into it, and this will stop the engine detting on 95ron fuel. To some degree this is correct however and this is the big bit in order for the ecu to pull timing and avoid det it first has to detect it, which means it has to be occuring this is massively bad for your engine. Every mapper I know or have ever talked to agreed that it is better to setup the map to aviod det and then have knock detection as an emergency back rather than to map up to det and let the knock detection correct for it.
The reason behind this is that det is very effective at very quickly putting holes in pistions or destroying ringlands, even the mildest amount willeakend pistons and reduce their life considerably.
FYI everyone spouting that JDM gt4's have more power than UK ones, this is down to the mapping for 100ron fuel, as soon as you put a lower grade fuel in the ecu will start pulling timing and reduce the engines power most likely to below that of a UK car if run on 95ron as the JDM ecu will be pulling to be safe where as the UK ecu will be running to map. This is further reinforced by the results of my old UK ST205 which during a GT4OC rolling road day comprehensively beat the majority of JDM cars present putting down 271BHP and 260LB/FT not bad for a stock (Low power!!) UK car...
You pays your money you takes your choice...
Rant over hope everyone looking to buy finds a good example and loves them as much as I do mine...
A European spec ECU tuned to run the engine on the lower
octane 95RON fuel as opposed to the Japanese 102RON
fuel. This is believed to be a slightly less “aggressive” fuel
map and as such the official power figure of the UK model
is 239bhp compared to the JDMs 255bhp.
( RON Octane Rating x 0.95 = AKI Octane Rating )
98 RON Octane x 0.95 = 93.1 AKI Octane (US measure)
100 RON Octane x 0.95 = 95 AKI Octane (US measure)
Mon Jul 14, 2014 9:58 pm
Mon Nov 03, 2014 6:44 pm
Mon Nov 03, 2014 11:01 pm
We often get these two questions:
Can I mix fuels?
What is the octane when I mix them?
The answer to #1 is easy. Yes, you can mix any of our race fuels. But remember – if your engine needs an unleaded fuel, you don’t want to mix leaded with unleaded. Doing so would make a leaded fuel which could still damage oxygen sensors and catalytic converters.
The answer to #2 requires a little math.
First you need to calculate the percentage of each fuel that will be in the final mixture. Then, use this equation to find your octane:
( [ % Fuel A ] x [ Octane of Fuel A ] ) + ( [ % Fuel B ] x [ Octane of Fuel B ] ) = Octane of Mixture
Here’s an example. Let’s say you mix 3 gallons of 110 with 2 gallons of 100 and you want to know the octane of the resulting 5 gallon mixture.
The percentage of 110 in the mix is 3/5 = 0.60 (60%).
The percentage of the 100 octane fuel in the mix is 2/5 = 0.40 ( 40%).
Plugging the information into the equation:
(0.60 x 110) + (0.40 x 100) = 66 + 40 = 106
So the octane of the resulting mixture is 106.
You can also determine the oxygen content of the mixture the same way – just use the oxygen content information we provide in place of the octane numbers.
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