Injector Size & Fuel Pressure

[Edub1]

It seems that my HP goals ~300-325, require the use of 550cc injectors and I have 460cc injectors.

Since I will be installing a MegaSquirtII and tuning from scratch, I'm wondering if it would be ok to stick with the 460cc injectors and raise my fuel pressure by 20% which would come to 52PSI @ 0 vacuum.

Asside from not having to source new injectors, I'm thinking this might improve atomization of the fuel. I can't see how this would present tuning issues as this would simply be worked into the tune.

Any thoughts?

[1995240sxSE]

460's put you pretty close, but they dont give much a cushion. I assume U got a walbro 255lph fuel pump? What are your afr's

[Edub1]

I have a Walbro 225 and my fuel is way rich with the rom tune but I'm going to retune with a MegaSquirtII.

I don't see why what I'm considering wouldn't work with a complete tune designed to work with the combo - perhaps someone will see something I'm missing.

[Edub1]

All you tech guys out there and nobody has any opinions on this???

[boriquaS13]

Edub I think you will still be limited to the amount of flow through the injectors themselves. Increasing the fuel pressure should give you some improvement but how much? IDK. I guess there is only one way to find out test your own theory.

[WDRacing]

I've been working 12hr shifts with my new job man. S13FX is onboard to assist modding KAT if you need to hit anyone up for anything.

I had a base pressure of 60psi for 3 years on my Skyline, not one single issue. It's a very good way to get more out of the injector, it also yields a better spray pattern. Go for it, just make sure your fuel pump isn't running out of steam in the higher rpms.

WD

[480sx]

Are there any drawbacks to running 50+ PSI?

Edub, if you buy 550's your gona be really happy that you did. Im running 550's and i got my MS powerd Ka-T running this weekend. Once i get my car idling and running well, you can burn my .MSQ file to MS and you will have a running car. Tuning idle is a PITA! However, my car started right up with the base map the MS configured for me based on my engine size and injector flow rate. Not well, but it still ran(until it got a little hotter and flooded itself ^^). Good luck with your build man, MS is a blast!

Im really glad that im gona have a few other guys on here to share info with. Sil80, me, and you so far are the only guys i know who will be running MS here. However i have a feeling thats going to change....

[S13FX]

Dang how did I miss this thread.

In any case the 460cc injectors will be able to flow with out having to increase the fuel pressure for your goals, but it will be border line. But your also right increasing up to 60 on 460 for that amount of hp isn't too bad too. As long like others said your fuel pump is good