FiveO 550s or 750s

[Niztec]

Hi has anyone tried using these injecs on their SR with any success? If so what is the max power you ever achieved on either?

[Niztec]

Nobody?????

[kandyflip445]

If they flow the advertised amount you can figure out your approximate max hp with a formula. I don't remember it though. lol It is, however, on this site so just to a search on here or google.

As far as a review on the brand I have no idea.

[Niztec]

Thanks Kandy:) I would prefer to work with the 750's as opposed to the MSD equivalent.


If they flow the advertised amount you can figure out your approximate max hp with a formula. I don't remember it though. lol It is, however, on this site so just to a search on here or google.

As far as a review on the brand I have no idea.

[codyace]

Thanks Kandy:) I would prefer to work with the 750's as opposed to the MSD equivalent.

So you'd rather trust rebuilt/redrilled injectors

MSD 72lbers will be fine. The 50 lbers are the ones that had issues 10 years ago running at 100% duty (go figure) and would go static.


Power wise, for the OP: 550's would be safe for 350ish whp, 750's good for 450-475.

BUT, when it comes to redrilled / non manufactured injectors, it's hard to ever really know. Use those above HP estimates just as 'references' towrads peak not fact.

[Niztec]

Cody I was under the impression msd 720cc injectors don't function too well @ 4bar. That's why I am a bit apprehensive towards the msds.

[codyace]

Cody I was under the impression msd 720cc injectors don't function too well @ 4bar. That's why I am a bit apprehensive towards the msds.

Most of the issue stemmed from the 50 lbers being overworked at underdeveloped for quite some time. Then again, there are countless other guys running MSd 50lbers safely for countless years now, so long as they aren't being pushed beyond their design.

With that said however, do you need 4 bar of base fuel pressure? 72lbers at 4 bar would really be in the 800cc range....if you really need that much fueling, I'd go with a 1000 cc injector and call it a day.

Don't discredit RC injectors either...same 'Lucas Type' injector. I just simply do not trust redrilled or reworked injectors.

[Niztec]

Cody what are the specific issues with redrilled injectors? I am assuming the main issues are spray pattern and lag time? Do you think that sustained 4bar pressure will over work the injectors? Enjuku says they are endorsed by enthalpy. It seems he has gotten them to work.

I agree with you with the rc injectors I have found them to be rather robust.

Most of the issue stemmed from the 50 lbers being overworked at underdeveloped for quite some time. Then again, there are countless other guys running MSd 50lbers safely for countless years now, so long as they aren't being pushed beyond their design.

With that said however, do you need 4 bar of base fuel pressure? 72lbers at 4 bar would really be in the 800cc range....if you really need that much fueling, I'd go with a 1000 cc injector and call it a day.

Don't discredit RC injectors either...same 'Lucas Type' injector. I just simply do not trust redrilled or reworked injectors.