swaussie

I have noticed in the past week a curious change with my standard Swiss STi7. Under WOT in 3rd and 4th the car revs normally to 5800 - 6000 rpm (same as it always has) but then it seems to "open up". The only way I can describe it is its like the old dual stage carbies. First stage opens under light throttle but when the right foot is firmly planted the second stage opens and you can hear the note of the engine change with the extra air being sucked in. Mine sounds the same, you can hear the noise deepen and the damn thing "reaccelerates" when its normally tailing off.
Any thoughts on if its the ECU "learning" or doing something new in this cold air (nicety) or boost spike (warning)?

P20SPD

iTrader: (1)

dont they have variable valve timing on them

Dyney

They do indeed!!!

swaussie

Although I havent noticed it so dramatically before I will put it down to that fancy schmancy variable timing thingy and if I get smacked in the head by a passing conrod I will know otherwise. Thanks guys.

Simon Lines

It's more likely to be a notch in the ign timing / knock control

Cheers

Simon

dazevo

I also have this kinda problem in my sti 7 ppp when accelerating i find the car seems well definatly does pull ease off and then pulls again especially at between 6 to 7 k revs its like a fair ground ride pulls hard up to 6k then really pins you in the seat till i change up at about 7.2 k revs, but not all the time only now & then whether its a one off or theres a problem dont know but its easily as quick as the evo 6 ive just sold daz.

PSI3

I've noticed a similar sensation to the above on my STi7 since having the PPP fitted, there is now a definite step in the performance as the revs rise around 6k, just put it down to the revised mapping of the ecu, only seems to be to the benefit of performance . I will take a bit more notice and note the circumstances.

simon

Eagle7

sounds alot like the effect of VTEC or MIVEC on an FTO.

the STI has variable valve timing, so i guess this is the engine going to the faster cam profile.

sammyh

iTrader: (1)

I would agree with Simon

Andy W

I have noticed a bit more acceleration at about 6250 rpm just before the boost starts to drop off in 3rd and 4th