APR Octane Maps

[Matimcfet]

Quick one,

What is the effect of running different octane fuel to the map,

I have 4 maps
1.stock
2.97 octane
3.95 octane
4. Valet mode

Its stage one but on the stock clutch, and Im running it on 98 octane. My problem is that on the 97octane map the clutch slips quote a lot. On the 95 octane map it doesnt slip as much and so puts the power down alot better. Will running 98 octane on a 95 map have any sort of negative effects or is this just like putting good fuel in a regular un-mapped car?

Thanks

[f00glee]

Wont have any negative effects at all, you just wont be getting the benefit of running a slightly higher octane. A completely stock car uses its knock sensor to adjust the ignition timing based on the fuel quality. I'm guessing the various APR, who will adjust the timing, also put constraints on timing in each map to to avoid the chance of pre-detonations. Maybe APR completely ignore the knock sensor and just rely on the user selecting the correct one for the fuel they're running.. not sure. In any case I wouldn't chance 95 when on the 97 map but vice versa will be fine.

(I'm mapped but not APR so not exactly sure how they do things)

Sounds like its new clutch time!

[Matimcfet]

Excellent thats fine, yes only using higher octanes, not using 95 on a 97 map.
Definately new clutch time! Looking into options.

Thank you!

[Matimcfet]

@f00glee could running 98 octane on a 95 map be why the car is struggling to start a bit?

[muff1991]

Personally I wouldn’t have thought that would make much difference, you might have a fuel pressure issue rather than an octane issue ?


Sent from my iPhone using Tapatalk

[Matimcfet]

just doesnt quite start on the beat, hard one to explain really but once the car is started it runs absolutely fine..

[muff1991]

just doesnt quite start on the beat, hard one to explain really but once the car is started it runs absolutely fine..

have a watch of this mate. I remember watching this a while back and he mentions hard starts sometimes and once started the HPFP manages to compensate for the in tank pump.

[Matimcfet]

@muff1991 did you mean to paste a link?

[muff1991]

@muff1991 did you mean to paste a link?

OMG yes.. haha! sorry about that. here you go:

(thanks for letting me know)

[Matimcfet]

Haha no worries, cheers for the link! So could possibly be the in tank fuel pump maybe not able to get the right amount of fuel into the engine after the map? But after starting the other fuel pump picks up the slack?


Sent from my iPhone using Tapatalk

[muff1991]

Haha no worries, cheers for the link! So could possibly be the in tank fuel pump maybe not able to get the right amount of fuel into the engine after the map? But after starting the other fuel pump picks up the slack?


Sent from my iPhone using Tapatalk

according to the humble mechanic yes, It makes sense I guess. might be worth having a poke around with VCDS as it could literally be anything.

[f00glee]

I spent ages chasing a "spluttery" cold start around. The thing which cured it for me once and for all was an inlet and injector clean. My long old thread on the subject:

https://www.mk5golfgti.co.uk/forum/index.php/topic,114226.msg1093509.html#msg1093509