Help Wanted! Found Something Odd With Power Fc Setting

[alex.a]

hey guys,

i recently bought a r32 gtr from a private buyer.

car has a fully built engine and is running a to4z with twin rb25 afm (green sticker) and the usual supporting mods.

now today i was going through the power-fc and noticed that the AFM selection was set on stock r33 gtr afm even though its fitted with rb25 afms???

so i switched the power-fc to the rb25 afm selection and took the car for a drive. now weird thing is the car drives alot smoother and comes onto boost earlier and the external gate open much, much earlier. BUT the car dosnt go anywhere near as hard as when its set to r33 gtr afm.

its weird actually, car makes all the correct sounds, revs out smoothly but just dosnt go anywhere when set on rb25 afm.. sort of feels like slipping clutch(its not! brand new twin)

im unsure of what to do? leave the power fc on the setting it came with (r33gtr afm) or switch it to the correct rb25 afm?

im getting it retuned in the next few weeks anyway so im sure the problem can be resolved then.

has anyone else come across this?

any help would be appreciated

thanks

[paulr33]

put it back how it was and get it tuned properly

they might have used datalogit and edit'd the AFM ramp directly (unlikeky, but possible) so even though its selected a BCNR33 it could have a completely different ramp. either way, changing it to something different and trashing it, is not a good idea, given it would be using a standard AFM curve to suit HR32/ECR33 (assumption, they might have edit'd that one too)

[alex.a]

thanks for the quick reply mate.

yes i understand what you mean about playing with settings and driving the car hard.

i only brought it up onto boost once and made sure i watched the knock level... but it was a once only trial and dont c the need to do again!!

however, i will drop by PITS in the next week or so and book her in for a tune.

thanks again

[Guilt-Toy]

thanks for the quick reply mate.

yes i understand what you mean about playing with settings and driving the car hard.

i only brought it up onto boost once and made sure i watched the knock level... but it was a once only trial and dont c the need to do again!!

however, i will drop by PITS in the next week or so and book her in for a tune.

thanks again

change it back to how it was and don't bother getting it tuned. leave it.

why do people have to touch something that aint broke?

[RRob]

Theres nothing wrong with getting a check up done on the tune.

[alex.a]

guilt-toy- well its not broken but its not exactly the smoothest tune!

plus i would rather get everything checked out for my own piece of mind! plus its cheaper then a rebuild if something was to go(or is) wrong with the tune.

thanks guys.

Edited June 11, 2009 by alex.a

[Moodles2]

Does anyone find it strange RB25 AFMs are being used with a RB26, how do they compare to GTR AFMs?

[heller44]

lots more headroom.

[paulr33]

GTR maf is 65mm

GTST maf is 80mm

they flow more and are larger in size

remember a GTST has 1 x 80mm afm and GTR has 2 x 65mm

so when you fit a PAIR of GTST afm's to a GTR, its a fair upgrade

[Adriano]

BY changing th esetting, you have richened it up. Lucky it didnt go the other way or you could very easily be looking at a new motor,