Rb26 E-flex Ignition Vs Boost

[6InlineTT]

I've got an idea. set anti-lag launch end RPM at 8000 and get a mate to film from outside the car. You know, for science

have already done this at 7000 haha I feel that the neighbours were less than impressed.

[6InlineTT]

you want peak cylinder pressure at around 12 degrees atdc,any more or any less and you lose torque, you therefor need to ignite the mix so it burns at a rate that gives peak pressure at that angle, as revs go up, the piston moves faster so mix needs to be lit earlyer or peak pressure will occur after the desired angle, and waste power, yet you dont want to advance to much as the other side puts stupid amounts of strain on the motor and wastes energy to.

however as more load is placed on the motor, more heat is in the chamber so mix burns faster, so timing needs to decrease to keep peak pressure at the right angle, or else your firing to early and can cause damage from to much strain.

this is on a motor that isnt limited by knock,

most rb25 with big turbos and huge boost will be knock limited at some point, so wont actually be able to be at 12 degrees atdc with peak cylinder pressure as the burn is to unstable and starts pinging so in these cases peak pressure ends up being later atdc to keep things working without damage

how do you measure this?

knock ears and a dyno,

increase timing in a cell while holding steady state on the dyno and watch the torque fiqure, it will plateau and then drop, at the start of this plateau is where you want your timing to be, any more or any less and your wasting power and arnt helping the motor at all,

if when advancing the timing it starts to ping before it plateaus, thats how you know the engine is knock limited, and timing needs to be put back to stop the pinging

slight changes in engine setups, and even just slight tollerance differences between motors, is what could make one map work perfect for one persons motor, and make another persons motor need a tow truck, so be careful when playing with ignition timing without the correct tools

interesting, thanks for the detailed response. Eventually I will have the eflex sensor tuned to run 98/e85 mix.

[G37Sam]

My 26/30 @ 1.6bar on 98 RON goes up to 22 degrees advance if that helps

[Kinkstaah]

These numbers make me unsurprised as to why my engine exploded

[Blackkers]

Everyone's quoting timing numbers but not saying what rpm its at.

Top right corner of my e85 timing map is 26 degrees (7500rpm) from Toshi and that was conservative. I don't think he liked putting 20 psi through the stock rb25

[G37Sam]

Yeah I guess it'd make more sense if people shared ignition maps rather than just numbers

[crashsvg]

hmmmmm.. as a tuner tuning on both road and dyno its not advisable to take timing maps from other cars... different turbo ,mods, compensation maps bla bla make a huge difference..

i made 415HP @20 psi with 22* on a 6262 on 91 oct

i also made 499 hp @21 psi with 27* on a borgwarner 8375 using the same 91oct with waiter injection.which would bring it up to 97-103 oct....

but whose to say if my compensation map is pulling 5* in the back ground . or if my finial timing is 27* but my intake temp is super low...

quick answer though...with everything working cool and proper fuel you should be able to go 18-20* at 20psi ...

it your street tuning you would feel the difference...go up 20* make a pull and make a pull at 17* if both feels like there pulling the same leave it at 17 once knock is not present.