when to switch to 72lb injectors

[cordes]

I know there are a lot of people who have run +30lbs of boost with the +40s. I have also read that they are more like 59lb. injectors hence the argument when some one made over 400HP with them for the first time.

With the FP at 55 and a custom cal it would seem from some of the information that I have looked at that one starts to push the +40s duty cycle when the boost gets up in the 30 PSI range in a car that can flow up top.

With the gaining populatiry of alky injection to allow for 3 bar + boost levels, and some of the guys who claim to be making power well past the previous generally accepted "limit" to how fast we can spin our motors, when should one considder switching to 72PPH injectors?

[86Shelby]

When I get bored with the power level the +40s provide me I will be going to 72s. ;) I've read of 400-425hp being supported on TIIIs with +40s, though they have been MAXXED OUT at that point.

[TurboGLH]

When I get bored with the power level the +40s provide me I will be going to 72s. ;) I've read of 400-425hp being supported on TIIIs with +40s, though they have been MAXXED OUT at that point.

One thing to consider about that is that T3 cars run their injectors at 100% at wot, vs the 85% duty cycle of t1/t2/t4 cars. I dont know if the cal your running retains that, but it would allow for a t3 car to make more power with the same size injectors.

[8valves]

One thing to consider about that is that T3 cars run their injectors at 100% at wot, vs the 85% duty cycle of t1/t2/t4 cars. I dont know if the cal your running retains that, but it would allow for a t3 car to make more power with the same size injectors.

Why would a certain engine ever run injectors at 100% DC? Most efi tuners start to get weary at the 85-90% range and look to upgrade at that point. Just curious really...

It's not so much a boost level either Brian, it's a fuel demand, i.e. power output. Reeves said he could've made 400 on the +40's, but plumbed in some extra injectors just in case I believe. I alreayd made the switch to the 72's for insurance if you will.

Aaron Miller

[TurboGLH]

Why would a certain engine ever run injectors at 100% DC? Most efi tuners start to get weary at the 85-90% range and look to upgrade at that point. Just curious really...

It's not so much a boost level either Brian, it's a fuel demand, i.e. power output. Reeves said he could've made 400 on the +40's, but plumbed in some extra injectors just in case I believe. I alreayd made the switch to the 72's for insurance if you will.

Aaron Miller

Since the t3's used the same injectors as the t2, in order for chrysler to supply sufficient fuel at wot they had to run them at 100% dc. If you own a stock t3 car, take it for a ride with a drb or some other monitoring box hooked up and watch the injector dc when you go full throttle.

[8valves]

No kiddin, wow. I never knew they ran on the same injectors, and tisk tisk Chrysler for more cost cutting tactics, even if it possibly could (although I don't think it ever did) cause someone an engine!

I would assume then that T3 guys upgrade injectors immediately then?

Aaron Miller

[Garret]

Where does one Aquire 72's and for how much?

[8valves]

FWD has them, you can check there for the price. You could also go search for other injector vendors and find something that would work if you feel those are either not enough, or too much for you. Lots of companies sell all kinds of styles of injectors.

Aaron Miller

[Garret]

I was planning on +40s, but seeing them max out on something the flows good up top (16v conversion) I believe I might have to setup up