V8Astro Captain

iTrader: (1)

Is there a decent junkyard source for these? I'm debating how to run a 4bbl TBI injection system on my Impala without matching the GDP ($$$). I want to run the EBL on a 7747 with a wiring harness scavenged from yet another junk P30 series 'tater chip truck. I found the part number for the bare Accel 4bbl TBI unit priced realisticly at $349 (instead of Holley 4bbl for $900).

My problem is the Accel TBI uses port style injectors. I found them on Summit for $90 a pop. Seems to me I could junkyard a set for less than $400...

Fast355

iTrader: (2)

WHY peak and hold? The EBL will drive standard PFI injectors from what RBbob told me at one point in time.

HaulnA$$

I bought a 4 BBL Holley TBI for a stroker project I did off of Ebay for less that $400. It was brand new and had 4 85 lb. injectors (old style). Granted, this was a few years ago but if you are diligent, you can find one fairly easily. If you can't find one, this place has a bunch of different P&H port injectors. Look in the performance injector page. http://www.injector.com/ . HTH

V8Astro Captain

iTrader: (1)

I checked his website. It says the EBL will drive up to 8 PnH port injectors. I assume it only does PnH. Maybe he or someone else on the design team will chime in.

I could be reading the website wrong tho...

Fast355

iTrader: (2)

RBob sent me this on 6-23-06.

I know for a fact that a stock TBI ecm will drive 4 peak and hold port style fuel injectors. Two parallel'd on each injector driver. The 1994-1995 Chevy S10 2.2 used peak and hold port style injectors (weird fuel rail though) with a TBI PCM.

HaulnA$$

With the $75 EBL injector upgrade to drive 4 TBI injectors you can indeed drive 8 P&H port injectors. HTH

Fast355

iTrader: (2)

The stock EBL will drive 4 P&H port injectors.

Grumpy

TBI, Peak and Hold Injectors are 1.2 ohms.

Port, Peak and Hold Injectors are 2.4 ohms.

Saturated in either variety are 12-18 ohms.

Just a FWIW

V8Astro Captain

iTrader: (1)

Now I really have no idea what to do

vernw

iTrader: (2)

So, if I'm reading this correctly - the EBL will drive 8 "standard" TPI injectors? I thought just the opposite was true...

Fast355

iTrader: (2)

It will drive 8 standard TPI injectors.

It will drive 6 as well.

The MPFI intake on my 3.1 using the EBL is a prime example.

Grumpy

If a stock TBI will run 2 TBI injectors that would be the same electrical load, as 4 port type PnH (2.4 vs 1.2 ohms).
If you want to run more then 4 Port PnH you need additonal injector drivers.
If you want to 4 TBI PnH injectors you need additional drivers.
You can run as many as 8 saturated injectors without issue.

Learning Ohm's Law, would be advisible.
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There is no *standard* TPI/ Port injector. There are saturated, or Peak/Holds. The most commonly used are saturated.
Using the proper terms is a good habit to get into.....

HaulnA$$

The last statement is not always true, at least from my testing. The LM1949 (which GM P&H drivers are, basically) datasheet states that the trip point from peak to hold current is 385 mV. When using a .1 Ohm current sense resistor as GM does, means that the peak current is 3.85 A. Using Ohms law R=E/I where E is voltage, I is current and R is resistance. At 13.8 V and 3.85 A, 13.8 V/3.85 I = 3.58 Ohms. Multiply 3.58 * 4 (for 4 injectors in parallel per driver) and you get 14.33 Ohms. This means that any set of 8 injectors measuring less than 14.33 Ohms each will trip the Peak and Hold driver into hold mode current of 1A total or 250mA per injector max. This is not always enough current to hold a saturated injector open, or so I have found, not to mention that with heat an injectors resistance will drop making the problem worse. HTH

vernw

iTrader: (2)

I agree, Grumpy. That's why I asked the question - I don't know which injectors are PnP vs. saturated. For example - the SVO 30's I've been running in my SR, and plan to start out with in my AFr/MiniRam set up, aren't those the saturated type? Which means thye probably won't work with the EBL, even with the injector driver upgrade...

The reason I was asking is because I don't know. But I also admit to a bit of laziness - I should have done a search to see what type the SVO 30# injectors are. So I am at fault here, sorry.

V8Astro Captain

iTrader: (1)

LOL. Do any of your vehicles have untouched electronics?

Grumpy

And without Ohm's Law you'd not have been able to figure that out!.
Thanks, for proving my point.
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Put an ohm meter on one, or just do some research.

ALL SATURATED ARE 12-18 OHMS.

If 2.4 ohms (since you're working with port) they're PnH.

vernw

iTrader: (2)

Did the research, found out they saturated ar 12-18ohms, and I know for a fact mine are in that range. So the "default" TPI.multi-oint injectors are saturated, not PnH.

Thanks for the info and education (again) Grumpy!

HaulnA$$

Ohms law is the first thing taught in the EE corriculum in college and it is constantly reinforced throughout. It is the foundation for all things electronic.

Grumpy

Your welcome, but please let's stick to using the accepted terms, ie saturated.
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Yaaaa.....

But, I was addressing the folks here, and I'd venture a guess, that not too many guys have actually used it, which was my point. Getting it down, allows, IMO, for a much better understanding of parallel resistance figuring, which is the crux of this thread.

V8Astro Captain

iTrader: (1)

I recently found this...

http://www.msdignition.com/2007/light.html

Check out the "Jammer" injectors at the bottom. The list them for use with saturated AND PnH type drivers. I don't see how that's possible.

??

HaulnA$$

They must be saturated injectors. If they were P&H MSD could not state that. P&H drivers, as explained earlier in this thread, can drive saturated injectors as long as the saturated injector(s) does (do) not draw enough current to "trip" the P&H driver into low current hold mode. Saturated injectors must maintain full current for the duration of the pulsewidth. Saturated drivers cannot drive P&H injectors since there is no low current hold mode and the high "peak" current draw of the low impedance injector for the full duration of the pulsewidth would either blow the driver or overheat the injectors. HTH

junkcltr

iTrader: (1)

You are right on both accounts. Don't drive saturated injectors with a PnH driver. Don't drive PnH injectors with a saturated driver. Since the PnH driver is in the linear region of the FET with a large V_drop across it then it heats up more (the reason the V8 $58 guys use a FET that can handle a large temperature). Saturated is nice because the power across the driver is about .3V * total_inj_current or about 2.5 watts for 8 injectors.....not much heat there.