injectors for 10psi

[spitz7985]

Hey guys,

I have a set of sr20 370cc injectors but I recently found out that the T3 I have has an internal wastegate set for 10psi. I'm guessing the 370s aren't good enough. I will be running a walbro pump.

Another question: At 10 psi, can I use the stock MAF and a rising rate FPR? If not, can I use the stock MAF and a s-afc? Thanks.

-Brandon

[Structure240sx]

ou will be fine with the 370's at 10psi on that turbo. i was running 9psi with 370's on a to4b with some room left. you should also be fine with the stock maf althought it will be maxxing out. you will need the safc to tune the 370's and it will also let you see if the maf is maxing out

[Frozen240]

Hey Structure, what was the max boost you ran with the 370's? Reason I'm asking is that I have the Nsport kit and I'm going upgrade to the 370's and I'm looking for a max boost target. I was thinking about 9 or 10 psi would be max. I guess I'll find out when I get it dyno'd

[:: orion ::]

This is on the edge, guys...

I did 248rwhp with 8psi from a T3/T04E...that's about the *safe* maximum of 370cc injectors.

Now, a T3 compressor isn't as efficient, but 10psi should get you to that same power level, or a little more. So those 370s will very close to or at 100% duty cycle...which is OK for sidefeed injectors, but leaves you no room for error...!!!

So be careful, "spitz"...you may be OK, but it could lean out on the top end under heavy load.

- - -

And "frozen"...a N-Sport TO4B at 10psi I can almost guarantee will max out those injectors...

It's not good to puch the limits...that's why I just changed from 370s to 50lb'ers...just to be safe.

- Brian

[Structure240sx]

i was running 9psi with the 370's. thats where my wastegate was opening. i didnt trust boosting it much more. i would only use the 370's as a replace for the fmu in the nsport kit instead of a way to get more boost.

[Frozen240]

That's my main goal, to get rid of the FMU. I really don't trust it. I'm currently boosting to 6psi and will bring it up to ~8psi with the 370's and a SAFC, and of course some dyno time.

[spitz7985]

Could I get an aftermarket FPR and raise the fuel pressure higher then stock to give myself a little leeway?

[:: orion ::]

Yes...as long as you can tune it to compensate for the extra fuel being sprayed all the time with the higher fuel pressure, then it'll work great.

So if your plan is 370s, AFC, and higher fuel pressure, you're good to go.

- - -

For example, if you added an adj. FPR and raised the base fuel pressure 10psi (vacuum line unhooked) to 53.5psi..then the 370s run like 410cc injectors.

Theoretical max of 370s:

370cc = 35.2lb/hrAssume 90% duty cycle is the safe maximum.Use .5 for BSFC

(35.2 X 4 X 90%) / .5 = 253rwhp is the safe max.

No bump that up to 53.5psi fuel pressure, and:

410cc = ~39lb/hr

(39 X 4 X 90%) / .5 = 280rwhp is the new safe maximum..

But realize tht as you cross the 250rwhp mark, your timing control becomes increasingly important...and you're more at risk to blow things up. Even if you have the fuel, doesn't mean you can safely run and not detonate...have to keep timing in check as well.

- Brian