Max HP of 42# injectors?

[KBCobra95]

I have a set on my car and my tuner said that they are maxed out (484 whp 496 wtq) I thought the 42's were good to 550 whp?I'm still running my stock fuel rails. Would changing the rails help any? He recommended 60#'s but I don't know. Please Help!!!

 

[KBCobra95]

TTT

 

[gmkillr]

Id have to say you are pushing the 42's to their limit, they are probably pretty close to 100% cycle duty. There are calculator's online that can tell you this.
Id say jump to the 60's too. Check out Anderson's site, I believe they have them on sale pretty cheap. You are always better to tune an injector down than to try and tune a smaller one up. Good luck!

 

[final5-0]

A VERY good Q

I think the CORRECT answer is difficult, at best, to find

I've been on these boards since around the time our cars were made.

Over the years, I've seen peeps continue to go larger and larger with inj size choice.

IMHO peeps have always tended to get by with too small of a choice.

One thing you see all the time is someone saying ... so many hp can be supported with such & such size inj. The hose up there is ... most of the time ... those hp values are fwhp & NOT rwhp.

What if the guy is runnin an auto trans? ... all the more error

anyway ......

Over the last couple years, I've really seen a rapid change to larger size inj's.

I think it is due to more and more peeps have the ability to gather data which shows the need.

Not all that long ago ... forced combos were good to go with 42's.

These days, you see more and more going for inj's in the 50/60 sizes.

From many things I've seen, hp alone is not enough of a criteria to use in making size choice.

IMHO, This is one of those rare times in life that one could say ......

"I'd rather be Fat ...... than Lean"

Grady

 

[gmkillr]

 

[Therian]

Grady makes excellent points as per usual. Another thing the fuel injector calculators don't take into consideration is how far you will be revving the engine. the more rpms, the more air, the more air, the more fuel.

for instance...Jay Allen recommended I use #50 + injectors on a 7500 rpm application...Naturally Aspirated!

 

[KBCobra95]

Thanks Guys! Next question: Would 60's be enough to support around 650-700 HP? The reason I ask is My next comboe is going to be a dart 331 with AFR 205 heads with high boost and maybe some giggle gas. Thanks!

 

[final5-0]

Thanks Guys! Next question: Would 60's be enough to support around 650-700 HP? The reason I ask is My next comboe is going to be a dart 331 with AFR 205 heads with high boost and maybe some giggle gas. Thanks!

I'd be wanting to talk to peeps who have done what you propose to do.

Maybe check out some forced combo forums or look around Hardcore.

Grady

 

[4Jenna]

I made around 550rw with 42s and 590rw with meth.

I would say 540ish rw give or take is about their max.
Your not only running outta inj but your running outta volume i.e lines/rails

I runs 60s now, and they are good to about 650rw

Chris

 

[358stroker]

I made 490 at the tires on a mustang dyno with 50's, duty cycle was only 70%.
Stock feed/return lines until engine compartment, then -6 feed lines to vortech fuel rails, 255in tank, 255 inline. I think I could make more power and be OK with the stock lines.