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The 550cc over the std injectors will richen up the mixture by say 35%.

The Z32 AFM will then reduce the rich mixture by say 13%.

So you only have to lean out the mixture via the safc by 22%.

BUT it doesn't mean it will work 100% as you may still have idle or just off idle issues with the AFR.

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cheers, thanks for that joel :)

ok can someone else confirm this?

The 550cc direct replacement Injectors will richen the mixture, while the z32 afm will lean them?

Thus cancelling each other out a little bit and allowing me more of a tuning range?

  • 2 weeks later...

Ok, injector problem may have been sorted.

Been confirmed that S15 Manual injectors are 440cc and side feed high impedence (Same as RB25 Injectors)

Going by buskies formula i think it works out to be 440/370 = 18% lean on all maps

If true, is alot easier to control and tune :D

And with the Z32 already sorted, then this looks like its a goer

With the Z32 hopefully it will pull in the amount of fuel thrown in as not to cause too many problems with starting warm/cold starts etc.. :D

EDIT: I recently picked up a new Bosch Z32 AFM for $285.

Part Number

F00E000202

Check out a newy and how much you can get it for before spending $200-250 on a second hand one. :D

With the Z32 hopefully it will pull in the amount of fuel thrown in as not to cause too many problems with starting warm/cold starts etc.. :)

 

EDIT: I recently picked up a new Bosch Z32 AFM for $285.

 

Part Number

 

F00E000202

 

Check out a newy and how much you can get it for before spending $200-250 on a second hand one. :)

Awesome!!

Where bouts did you get it? What exacly is the difference between a nissan/tomei/bosch Z32AFM?

Now i just gotta find 6xS15 Injectors for a descent price :Oops:

How much power can i get out of the 440s safely? ~240rwkw?

Hey Knore,

Where did you get your info on the S15 injectors? Just wondering as I and a lot of other silvia owners were under the impression that S15 side feed injectors were 480cc.

Also, do you have a Z32 afm on your car now? Does it run OK with the SAFC? I picked up a SAFC the other day and have an RB20 AFM at home I want to use on my CA.

Posed by darrinspencer:

"From what i have read on the silvia site S15 manual turbo injectors have been quoted at 448cc and 480cc. 448cc seems to be the most common quoted flow

S15 auto's are quoted at 370cc, but I can not confirm for sure, only what I have read.

448cc will be good enough for upto 260-270rwkw which is more than enough on stock internals on a Rb25

I am chasing 240-250rwkw so these should workout well, and do not need to spent the extra dollars on 550cc"

Im not sure if there is two versions, 480 and 448?

Why the hell are s15 injectors so big? Even modified they wouldnt use anywhere near all of that 480cc's

Either way, 480cc will still be alot easier to controll than 550s

480/370 = 29% - 13% (z32 afm) = 16% rich. Whats the lowest adjustment point on the safc2? 600?800rpm? This would allow you to tune it for idle if so.

Hey joel, how did you work out that using the Z32AFM over the RB25AFM will lean 13% across the board? And is this 13% at 600rpm all the way to 7000rpm? it doesnt change?

knore.. I have no idea.. It was an estimate.

If you notice in the first few posts I said

The Z32 afm will pull out another 13% (guesstimate) from that 35% so I think it would work fairly well. :)
Thinking about it I think it is much more than 13%, probably closer to 30% if not more ?!?
knore.. I have no idea.. It was an estimate.

 

If you notice in the first few posts I said

 

Thinking about it I think it is much more than 13%, probably closer to 30% if not more ?!?

The SAFC2 has an option for running different AFMs, So if you set that to Z32 wouldnt the car run as it was the standard afm? :confused:

If it was something like 30% then it would be a godsend when put with the larger injectors :)

The SAFC2 has an option for running different AFMs, So if you set that to Z32 wouldnt the car run as it was the standard afm? :confused:
If that were true the SAFC would be simply converting the the voltage back to the origional RB20/25 values. Hence it would be a pointless excersise.

The SR20's AFM is a restriction (40mm vs our 80mm). Hence upgrading the AFM to the larger item will allow the turbo to become more efficient.

This is why it is documented as using a different larger AFM in the SAFC2 manual.

I would imagine using a RB or Z32 AFM on the S14 (as listed in the SAFC2) & setting it up as per the manual settings will have the ECU seeing the same airflow vs voltage as the origional AFM. The upside being there is a much less restriction in front of the turbo now so it is able to spool earlier and make more average power.

Hope that makes sense, I'm a little buggered after last nights :ddd:

You really need to head down to a tuner and ask them the voltage difference between the RB & Z32 AFM. Any decent half arsed tuner will know off hand. :)

But being a 33 you should be able to get it sorted thru the site in the states with english manuals...

Sometimes you need to take a shuffle back in order to walk forward.

A PFC with HC would have to work out cheap if you fence all your exsisting fruit...

An a path well warn is littered advice...

TT

But being a 33 you should be able to get it sorted thru the site in the states with english manuals...

Sometimes you need to take a shuffle back in order to walk forward.

A PFC with HC would have to work out cheap if you fence all your exsisting fruit...

An a path well warn is littered advice...

TT

Very true, but this is pretty much my only option..

My car is automatic.. And no stand alone management can control the automatic without affecting gearchanges and damaging the gearbox.

So given the circumstances.. This is the only real option i have if i want to do this project.

I dont have massive goals, it will be mission success if we achieve 240rwkw which will easily happen if we can get it all to work properly.

Has ANYONE run a different AFM with the SAFC2?  

And does anyone know how much a Z32AFM compared to the standard RB25AFM will change the air fuel ratios??

Yes and it varies a lot The voltage ramps are not parrallel between different AFM's ie; you can't just add/subtract say 10% and expect all the A/F ratios to be OK. I have had to add nothing at low rpm's, take a bit out at mid rpm's and add a lot at high rpms. You need to tune, it will take less than half an hour on the dyno for someone wiht any decent tuning knowledge.:cheers:

Yes and it varies a lot   The voltage ramps are not parrallel between different AFM's ie; you can't just add/subtract say 10% and expect all the A/F ratios to be OK.  I have had to add nothing at low rpm's, take a bit out at mid rpm's and add a lot at high rpms.  You need to tune, it will take less than half an hour on the dyno for someone wiht any decent tuning knowledge.:cheers:

Ok cool thats the answer i was looking for, ill just put some approximate values in so i can drive there with the injectors in. Then sort out tuning with them and the Z32 when i get there

Thanks again SK! :)

  • 1 year later...

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