GIZMO

iTrader: (8)

If you are in the 70's (WOT/peak) you will probably be giving up quite a bit of low end. Also, 11.8 seems way too rich. For maximum N/A power you should be much closer to 12.9 at WOT in high gear. I'm not sure about the stock computer, but with DFI, etc. I have found that I have to compromise a little on A/F (richer) on the low end, because of the rate of acceleration that the motor sees in first gear vs high gear.

ws6t3rror

iTrader: (3)

I did not say it wouldn't idle or drive plenty fine. **** carbed engines are running all over the road anywhere between 12 and 16:1 a/f ratio and nobody knows the difference with them either until somebody tunes it up for them. What I said was the adjustment is not as fine and fuel control can be improved by running the right injectors ie it will run smoother. I mean not that I know anything about it, people confuse my 24x/24x cammed 355 with a cc503 at idle all the time with no bucking or surging at low rpm cruise. Let me ask you this, have you ever tried anything else besides your current injectors? If you haven't then how do you know? I just happen to be a bit opinionated about this since one of my good friends owns an injector shop. You would be shocked at the things you can learn just by watching different brands and different pressures on the test bench.

If you're happy with what you have thats great, I don't think you should spend any cash at all on changing it. However, just because you can get away with it doesn't make it best.

C_Rules

iTrader: (7)

yeah 12.7-12.9 seems to be the consensus but 11.8 is where it made the most power at. i tried other a/f ratios but 11.8 semmed to be the sweet spot on seperate ocassions. car has had its bugs and is probably the closest its ever been to being 100% after years of playing around with it and getting through all the bugs which proved to be ridiculosuly hard to find. car has always been a stuggle. just as i was getting the tune perfect trans took a crap on me two weeks ago (not the first time). however when i get the car back ill finish up the tune and take it to the track rental coming up. then i'll really now what a/f is best for my setup. im pretty much done with the dyno tuning; taking it to the track to tune it for the results that matter.

1badzee

iTrader: (12)

I wasn't challenging you or anything, just simply asking for my sake. Can't hurt to learn something new. To answer your question, yes I have tried other injectors (sizes and brands). From stock 24# to ford 28s, accel 24s, holley 36s and now the ford 42's - so far the best has to be between the stockers or the 42's. Stockers when the car wasn't tuned and now that the car is tuned for the 42's, it runs exceptionally good. I still want a smaller injectors though.

GIZMO

iTrader: (8)

To me a dyno tune is the right place to start. It is a controlled environment. It really gives you a good idea of where you make your best HP in high gear. As you have said, the real work starts when you tune at the track.

Good Luck,

Daren

ws6t3rror

iTrader: (3)

If the 42's you have now are the bosch design 3 (skinny) injectors they are some of the best ones you can get easily that will fit our application. Most of the newer injectors will take 60psi and that usually improves atomization. The trick is to figure out what the flow is with the higher pressure and design around that. I prefer to run high pressures and on ethanol, but I am still in good shape on gas if I turn the pressure back down to 43psi. I will warn you that it takes a pretty stout pump to handle the demand with ethanol at 60psi.

1badzee

iTrader: (12)

They're the older larger ones

TasTe_GOOD

iTrader: (1)

The reason why I had started this thread is because I saw a set of 42 lb injectors for 160 dollars. I knew that they were way overkill, but it would be nice to not have to swap injectors every big mod I do. Right now I am putting the car back together with a cc503 cam, but next year (the day after I smog the car in april), I will be going with a bigger custom cam. Even then 42lber's sound too big.

So i'll keep looking for the right injectors then. Thanks for the help.

C_Rules

iTrader: (7)

duty cycle is in the mid to high 40s at WOT

GIZMO

iTrader: (8)

If that is the case, you are leaving a bunch on the table.

C_Rules

iTrader: (7)

how so? just trying to get a better understanding of the dc principles.

GIZMO

iTrader: (8)

I think that it all comes down to fuel atomization. I agree with the max. 80-85% DC and have found that my stuff runs best if I aim to hit that number at WOT at peak engine demand.

moehorsepower

iTrader: (3)

Well Like I said I run 85lb NA, only because I removed the supercharger and installing a Turbo and didnt want to purchase another set just for a short time. By dialing in my MAF, IFR and PE mine idled perfect, no bucking or surging at low speeds and smooth through out the rpm band. Of course this was not optimal but this was just for a short term use..I agree with Giz where a 40% duty cyle @ Wot is not the very best approach, the injectors will be too lazy..