Limits of the stock MAF?

[Phantez]

I looked around on a few forums for this, but all of the info i found was for s13 and s14 SR's and i'm not sure if the s15 SR is different. I swapped a stock s15 SR in my s13 and I'm trying to look up how much boost I can safely run without upgrading the MAF or injectors. As I understand it, the stock injectors on the s15 are 450cc, so i would think the biggest limiting factor is the MAF. I have a front mount and apexi exhaust. I'm currently running at ~12.5 PSI, but I feel like i could probably bump it up a bit more. How far can I push it?

 

[spoonman]

14 psi is about the limit 16psi for a second or two, providing you have a good fuel supply, and a good intercooler keeping in mind the ambient air temp, over 25C (you can figure out the US temp that comes to) and i would not run over 14psi, at least a heat 7 spark plug, 8 would be better, and i would not have lots of faith in the mixture at 6000 and higher so i would not have the revs up there for anymore then 8 seconds, i,e not drift limiter bouncing for a long time. In a daily driver it is fine at 14 as long as you keep in mind that the higher the rev the less healthy it is for the engine, not death but just less healthy.

Which is why the car is factory mapped for 8 - 10 psi. The SR's AFM are not very high flow reading, the Pink Sticker AFM off a RB25DET reads a bit higher then a SR's along with the VQ AFM but as you are probably already aware its the Z32 which reads a lot higher.

SR - 14psi
RB/VQ - 16psi
Z32 - 18psi + not sure on how high before a MAP is needed.

Stock injectors for a manual S15's DET are 480cc and the auto is 380cc or something gay like that. the 480's are a red/brown colour and the 380?? are purple.

ANYone else feel free to correct anything where you know otherwise

 

[Auss15]

The Z32 is the best upgrade it has a wider band reading and is a lot easier to tune, and you are right Spoonman re injector sizes and colour

 

[Chriscooke]

I believe the maf on the s15 is the same as the one on the 14a which can handle 15psi of boost easily and if mapped correctly 17psi although this tails off at the top end. That is pretty much maxing it out though and needs a map which supports it.

 

[Phantez]

That's a little better than I thought. How far have people pushed the stock injectors when having a proper MAF?

 

[reepers13]

z32 upgrade, well worth it

 

[Phantez]

Yeah I know it is. I still have one from my old ka-t setup. Its just a matter of getting the car tuned for it