69-chvl

iTrader: (11)

Any reason to change my 80lb Siemens to 80lb low imped if the change wouldn't cost any cash (even swap)? Maybe a better idle and sharper response from the low imped units is what I was thinking.

soundengineer

iTrader: (16)

you just stated the good reasons to change...
it will respond better at short pulse widths....

I have never found a downside to going Low impedance as long as the controller can handle it.

69-chvl

iTrader: (11)

Thanks Sound!

I guess what I should of asked is if the difference would be very noticeable vs maybe a splitting-hairs situation.

soundengineer

iTrader: (16)

its usually pretty noticeable at idle once you get to the point where the previous injectors cant open fast enough....

I couldnt tell you if you are there or not... but I know 80's is usually at that point where it makes a difference for most people

69-chvl

iTrader: (11)

Right now the 5.3 with the LS6 cam is idling pretty good (I think anyway) at about 750 with a PW of 1.4-1.5, DC = .5%, 31 kpa. This is w/o a trans hooked-up. My guess is that idle speed will have to go up when theres a trans/converter hooked-up.

It idles smooth with the "rough" tune. But hey, if it would be better with the low imp injectors why not!!!

stevieturbo

Unless your current injectors are a very old design, save your money.

Modern highZ's are better than old and generally most lowZ's in pretty much all respects

You should have no difficulty with a good set of 80lb highZ injectors.

69-chvl

iTrader: (11)

Now Steve you realize this is the opposite of what I've been reading? Everything I've read states the low Z's out perform the highs everywhere. Unless what I'm reading is old info. I have Siemens 80lbs (actually Ford Racing) so I would imagine these are newer.


Having said that my engine seems to have a smooth idle and is real responsive when winging the throttle. Don't think I can get it to idle lower than 750 - it gets rough under that.

SPRAYED 01

iTrader: (22)

I couldn't imagine my high imp 80s idling any better, what kind of issues are you having?

69-chvl

iTrader: (11)

None that I know of, just wondering if it would be better!

stevieturbo

That may have been the case 10 years ago. And almost even 5 years ago. But certainly not now.

Back then it would have been almost unthinkable to have 2000cc injectors running an engine sweetly high or low. But today it is quite common and easy....only with highZ injectors.
HighZ has come on leaps and bounds. LowZ hasn't really moved at all.

Wicked69

I run low z 160's with the Holley HP EFI. It has taken a while but mine idles excellent. I idle mine around 950. I can run it lower I just prefer it at the rpm. You can hear the cam a little better with the higher idle. The Holley can run the low z's so that worked out perfect for me.

I have always heard that high z would be better if you can afford them. I couldn't.