Dyno Delema

[s13onevia]

hi guys just wondering i just bought a pfc and want to get it tuned

car- 97 r33 rb25

i have the following mods

pod, boost controller, fmic, turbo back 3 inch exhaust, mod plenum (forward facing trottle) and pfc

now i have been doing a few runs and according to my pfc i have got my injectors to 92%. does this mean that they are nearly out of flow? what power do stock injectors flow to?

what im getting at is if i go to the dyno get it tuned bla bla bla, then the guys are going to say if you get a fuel pump we can sqeeze a few more hps out, therefore having to go awy and get two tunes.

can i get an adjustable reg to bump up pressure??

also since ive installed my pfc it seems to idle @ about 1300 when before it was about 950 rpms? and now my check diff lights come on on the dash??? any ideas?

cheers

Edited February 21, 2006 by s13onevia

[rb20inside]

a duty cycle of 92% means they were running at 92% capacity.

i believe the standard rb25 injectors are 370cc which is about 370 engine hp. confused how you could be nearly maxing out your injectors on a stock turbo. you must be running some seriously high and dangerous boost.

you could use a rising rate fuel pressure regulator to get a little more capacity out of your injectors but it is probably not the desired method.

and why dont you just install a fuel pump before the first tune?

[R31Nismoid]

If the injectors are @ that duty.

more than likely means you have a stuffed fuel pump.

You didnt list is as something you have taken care of.

So i would immediately get a bigger fuel pump and then you should see a major improvement

[Tangles]

My injectors were at 78% dutycycle when my stagea had 140awkw @ 10psi

I added a Bosch 040 fuel pump and a Nismo fuel pressure regulator

Now have mid-60's% dutycycle with 160awkw @ 12psi

So yeah Id recommend the bigger fuel pump & FPR to help the injectors, or you'd better grab a bigger set. You dont want an injector to bite the dust, as your donk wouldnt last too long!

[R31Nismoid]

You really dont need a FPR using a stock turbo.

As long as you have the fuel pump, thats top of the list

[s13onevia]

so a bosch 040 should cut the mustard, me must have one then

any ideas on the light on the dash??

cheers guys

[paulr33]

do you mean A-LSD and the SLIP lights?

a GTR33 pump is a direct fit and will suit your power requirements correctly

[benl1981]

Well if you haven't had a tune yet then this is probably not true:

If the injectors are @ that duty.

more than likely means you have a stuffed fuel pump.

The PFC has no idea of your fuel pump condition as it is just going off the standard maps.

I think running 10psi I got close to 90%injector duty cycle. After a tune this was reduced to 69% and making a lot more power.

You will need to see on the dyno how your AFRs are.

Edited February 22, 2006 by benl1981

[Wazz]

Well if you haven't had a tune yet then this is probably not true:

The PFC has no idea of your fuel pump condition as it is just going off the standard maps.

I think running 10psi I got close to 90%injector duty cycle. After a tune this was reduced to 69% and making a lot more power.

You will need to see on the dyno how your AFRs are.

i'd say this blokes hit the nail on the head.. the car hasnt been tuned yet so its simply running off the base map so go get it tuned and see wat it does than..