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-   -   Fuel Pressure at Idle 750cc injectors? (http://www.the370z.com/forced-induction/103778-fuel-pressure-idle-750cc-injectors.html)

pokeyl 05-16-2015 12:20 PM

Fuel Pressure at Idle 750cc injectors?
 
Anyone running 700 or 750cc injectors with a non bypass (stock with a larger pump) system and know there fuel pressure. I just added a port and if the electronic sensor and the rest of the electronics are correctit is over 50 PSI at idle. I falls to 37.5 at any throttle setting above idle. I think the short cycle time of the 750cc injectors with the higher pump volume is more that the factory in tank regulator can bypass.

KratikosG37 05-16-2015 05:56 PM

Take it your under boost? Be better if you listed your mods in the thread.

pokeyl 05-16-2015 06:18 PM

GTM 1.5 SC, 750cc injectors, 255LPM pump. Custom tune from Bear383's file custom 82mm pulley (13 PSI)

Items in work - stealth nitrous with remote opener.

When I add the extra fuel with the 750cc injectors I need to make sure the fuel pressure holds. A 50 shot ramped in as a function of RPM (gears 3-6) should produce 650 RWHP and 500-ish torque smooth enough to make the stock internals last.

pokeyl 05-18-2015 06:57 PM

I took some more readings 63.75 at idle. 56.25 off idle. any toughs? before start 48.75

phunk 05-18-2015 07:29 PM

Your injectors have nothing to do with your fuel pressure.

Most likely, you upgraded your fuel pump, and did not modify your pump module to support the fuel pump.

http://www.the370z.com/forced-induct...ml#post2784717

pokeyl 05-18-2015 08:23 PM

Quote:

Originally Posted by phunk (Post 3201709)
Your injectors have nothing to do with your fuel pressure.

Most likely, you upgraded your fuel pump, and did not modify your pump module to support the fuel pump.

http://www.the370z.com/forced-induct...ml#post2784717

CORRECT I did not, but I will. Thanks

ANMVQ 05-19-2015 02:53 PM

1.5 SC and NOS this is going to end well :/. Why people why

Jordo! 05-19-2015 03:23 PM

They may have a different latency setting too -- are you sure you have all the correct spec data inputted into the fuel injector tables?

Examples of what I'm talking about:

Theory: An Injector Model « Moates Support

https://github.com/javiermuniz/tunin...jector-Scaling

I think on uprev you can adjust this -- possibly by way of the k multiplier?

phunk 05-19-2015 04:04 PM

Injector latency settings will not have any side effects on fuel pressure. I have never seen a latency table in the UpRev before, but it all gets tuned around anyway.

pokeyl 06-02-2015 08:48 PM

2 weeks on the road, back now. After some math, I have a 11.5 PSI drop in fuel pressure from idle to WOT. Cruse is almost the same as Idle, only a 2.5-3.2 PSI drop. I can't be sure if of the starting pressure. I do have gauge that reads in .25 lbs but it needs calibrated. I hope to see the Idle pressure come down with the next fuel system mod. I have a spare stock pump assy and will be installing a 340 LPH in it with HD wiring and DPST high amp relay.


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