To calculate max hp simply multply flow rate of the injector by 2.04. So for 24lb injectors, max hp is 49hp per injector or 392hp for a V8. There are more accurate calculations factoring in duty cycle etc, but this is an easy guide.
I think AP's old XR8 still had the 24lb units though when it was making 220rwkW+?? I could be well wrong though! :wnc:
30lb injector kit is the same price as the 24lb!! Currently being US$219, so convert, add import duties / taxes, and freight... also see what price the good man John (LunaticSVT) can do for you as he distributes a metric assload of parts now in the States!
Same time ideally. If you bump up your injector size, you either compensate by "tricking" the computer with a new MAF, or you have to get some computer work (uni-chip, tweecer etc etc).
As Sparkles said, injectors are cheap in the US (better than the $350 EACH I was quoted the other day for 19lbs from Ford). Another good thing, MAFs are cheap too.
Also, its a very good idea to check your A/F ratio after changes such as this. Even though the MAF & Injectors are supposed to be right, they can still be out, and a lean condition is baaaad mmkay !
No prizes for guessing what I'm doing in the next couple of weeks
sweet! Now to ask another possibly stupid question. changing injectors should happen before new manifold or after. I'm planning to get the ute on a dyno real soon to see how her vitals are reading. Is the stock AU maf a good flowing device? What can i hope to get out of the maf change alone?
It doesn't really matter with the Intake manifold change. At the same time would again be good, simply because its less times you need to pull the thing apart
I can't really comment on the stock AU2 maf, but I have the feeling its fairly good standard (someone pls confirm or deny). Maf change alone (before significant other work), I wouldn't expect much at all (probably be lucky if its noticable). . .
Its going to be better for me, since I have a poxy 55mm macca's straw at the moment ( I *think* the AU's run 70mm ? )...
excellent! thanks for all the feed back. i removed my upper manifold and when i looked down the runners the heads were about 20% larger. i expect some definite gains from manifold change(prolly trick flow). Waiting for dyno time first to see what my starting point is.. any ideas for cam specs to suit 6500 rev limit. i was thinking 224 @ 50 but wondering about comp sys... would it be better to go chip torque or more like a unichip? Once again thanks for all the help.
MM&FF magazine did a comparison between intake manifolds on one of thier 5.0L engines producing 250rwkw. The difference between the stock explorer intake used on the AU's and the trickflow intake was only 3hp and the torque figures were more consistant with the explorer too. Explorer made 326hp 339ft/lb Trickflow made 329hp 345ft/lb and the Edelbrock made 336hp 348ft/lb.
I was going to change my cobra intake to a trickflow or edelbrock until I found this comparison.
Once again thanks, prolly saved me lots of $$$$. Did the article say what heads were used? Main reason i was thinking of the change was because of the diference between inlet port for heads and exit of manifold. Any idea about TB and Maf on AU is it more worth my money to just change the cam and install unichip.
Test engine had Trickflow alloy heads flowing 251/193cfm, Anderson N-65 cam which apparently is really wild, 30lb injectors, 77mm MAF etc.
MAF would probably get you some more power with the porting and cam upgrade. The AU's ran a 70mm MAF but the way it was designed still looked restrictive. Upgrading the stock 65mm throttle body probably won't give you anything IMO.
I would be trying to find a 70mm T/B, that was probably the best BFYB mod I have done on my car, total cost was about $250, after selling my old one, buying a new gasket etc. I gained a total of 3mph down the quarter. Also, try getting the inlet manifold ported as this will give more gains again.