Injector flow vs pressure

[soslow91]

I've seen it stated in other posts that POD's outflow 370's at the same pressure. So my question is does anyone know how to figure out how to figure out how to convert them at what would be considered the stock pressures for a VE pump and a 7100. I found the formula for gassers before but I don't have it anymore and without looking I don't know how much pressure either of these pumps puts out.

 

[BushWakr - RIP]

soslow91,



First, and most importantly... . WELCOME TO THE RANCH...



I don't recall >> ". . that POD's outflow 370's at the same pressure... "



I do know that the Lucas injector flows more fuel than a 370, (which are run on the P7100 pumps with much higher pressures) when both are in "stock" condition. Meaning not extrude honed, or altered from the factory condition.



The stock VE pump has an upper pressure limitation of roughly 8,500 psi, which varies based on RPM.

I do not have any specific info on the lower (min) psi, however it must exceed the 270 bar level (3969 psi) to flow fuel on the more aggressive injectors. Lucas run around 250-255 bar =

(3675-3748psi).

Some a touch higher, some lower, but that is a rough median rating.



I would take a stab at roughly 4000 psi at idle... . just a guess mind you.

If you happen to come across a more definitive figure/RPM please post that if you would.



This next point was debated by looking at the pump spec plate... the stock VE in new'ish condition is rated at approx. 74cc/per 1000 strokes as per pump plate spec.

The Bosch manual says 120 mm(3) per stroke. That seems to be confusing, at least to me anyway...



As an aside... ...

At the present time, I am running the Lucas injector, a PDR HX 35/16, pump tuned up nearing max, advanced timing, mandrel bent exhaust, K&N, open air box etc..... I have enough fuel at this stage to drive the pyro (using the 14cm N/W) to roughly 1700*F, on a 20 second dyno run and 1500*F on a WOT run to 100 MPH. Lots of fuel, way too much temp.

My 16cm, porting the exhaust manifold, turbo inlet, has brought the highway temps down to roughly 1350-1400*F on a WOT run to 100.



Bob.

 

[dpuckett]

I read in the magazine in the article about the evolution of the B series fuel system that the VEs were good to 10K psi; P7100 to about 15K psi. Seems I recall picking up somewhere that the VE had an idle pressure of about 5000. Mine is turned 2 threads past the lock collar (not done by me), so it is probably putting out its max pretty quick. Lays a cloud if you get on it at lower rpm. ANyway, back to injectors. Having a higher pop pressure will make a finer fuel spray, all else being equal. But it has the same effect of retarded timing. That is why in some sigs you will 1. 7+ mm when running PODs, or some other performance injector. Hole size and placement, along with number of them, also plays a part in how the fuel sprays and burns. I would like to (time, $$$ permitting, and getting someone to do it) try honing some stock 92-93 tips to about the size of stock PW holes, or a hair bigger. Should flow 16. 6% more than the PWs, right? (6 vs 5 holes). They're set up for the spray angle, and the 6 holes would give a more even spray than 4. I hate smoke; wasted fuel and money.



To the original question; now that we know the pump pressure outputs, the "stock" spec for injectors coupled to the VE is 3550psi; 3822 psi for P7100 pumps. At least that is what my CHilton book says. It has been wrong before.



Daniel

 

[soslow91]

1000 characters....Doh

First off thanks for the welcome glad to be here





I guess I should be a little more clear about my goal here with this question. I'm trying to determine what hp you will end up with if you take a 370 and modify it to work in a first gen or a POD and modify it to fit a second gen or what a number of other injectors will do if you put them in an application other than the one they were originally intended for.



Piers says POD's are 52hp in a 91-93 or 212hp. Say POD's flow the same as 370's 212/370 is about . 573 going by that a 300hp injector=172hp injector in a first gen or smaller than an 89-91 injector and 215's from a second gen would make >123 or in other words would be allowed to sit in the non-smoking section and would long for the acceleration of a dsl rabbit. On the other hand maybe the second gen guys would like this theory better as it means the stock injectors from one of our trucks would have close to 280hp not bad if they were cheap enough to warrant modifying them.

 

[dpuckett]

Re: 1000 characters....Doh

Originally posted by soslow91

First off thanks for the welcome glad to be here





212/370 is about . 573 going by that a 300hp injector=172hp injector in a first gen or smaller than an 89-91 injector and 215's from a second gen would make .

I've read that the 370s make about the same gain in a 2nd gen as the PODs do in a first gen. The 370 injector is from a 370 hp application, but I believe it has a different pump or at least different settings, IE flows more fuel per stroke than the 215 or 175 P-pump. THe best way I can think of to compare them is to get the specs on hole size (I believe both are 4-holers) and compare the two. THe one with the bigger holes will naturally flow more fuel at the same pop off pressure and pump pressure output.

 

[soslow91]

Originally posted by dpuckett



I would like to (time, $$$ permitting, and getting someone to do it) try honing some stock 92-93 tips to about the size of stock PW holes, or a hair bigger. Should flow 16. 6% more than the PWs, right? (6 vs 5 holes). They're set up for the spray angle, and the 6 holes would give a more even spray than 4. I hate smoke; wasted fuel and money.



Daniel

The end of that quote pretty much sums up the reason for my curiosity POD's are known for smoke and PW's don't flow as much. The suggestion of comparing the hole sizes is a good one and if anyone has this information it would probably warrant a new thread. It would also be nice to know which injectors are sac type and which are not.



I guess for the time being I'll limit my bad math to one injection pump at a time. If PW's are 28hp and 160 is the baseline 188x6/5=225. 6 POD's are 52hp or 212 so that sounds good to me but would it weaken the tip too much.

 

[JLEONARD]

The 370 injector is from a 370 hp application, but I believe it has a different pump or at least different settings,

FYI.....

The current Cummins 270, thru 370 hp marine engines use a Bosch 7100 series pump. (I have a 270 in my boat)

The older 250 hp marine engines use either a Lucas/Cav pump or a Nippondenso pump.

Jay

 

[mopar2ya]

pod's and 370's

hello, i have been playing with a set of 370's in my '92 d350, you should see a 100 hp gain, i got 260 hp now, if you wanted to compare pod's to 370's,look at it this way,pod's are 390's, thats about the flow difference, hope this help's tankx joe