If I'm wrong then tell me why I lost MPH at the track and HP on the dyno in my truck (and another one I tested...nice when the guy owns a dyno) with more plate and no gain in boost or EGT's, then tell my why the plate in my race pump is in the stock position....if you still don't believe it then push it forward.

Jim

 

[quote author=J.R. Adkins link=board=7;threadid=21630;start=0#msg203071 date=1067450100]
[quote author=Jim Fulmer link=board=7;threadid=21630;start=0#msg202840 date=1067395090]
Play with your plate but remember 18mm of rack travel is better than 21 (max) I have proved this at the track and on the dyno....more isn't always better....guy thing!

Jim
[/quote]

Jim I do agree to this statement to a point. Most street driven setups cant handle more than 18mm.

J.R.
[/quote]
Jim you have a hx35 and a ht3b. With the amout of fuel VS air I say that you need more air to handle more fuel.(unless you shoot water) I ran the same setup quite a while back. Then I put a hx40 in place of the 35.... it was better. Then I went to a H2e....even better yet. Get my point?? See where I said MOST? Have you ever ran another set of twins besides a ht3b and hx35??

 

Dang Bro this is starting to look like a tranny thread

Yes I run a 35/3B you know that, yes I need more air and a 40 on top will be next and no I've never ran another set of Twins. The one thing I have done with this set is push it from 450 to 700 hp with both the stock pump and the race pump, the above comments are what I've done to my truck and another, I really don't think I need anymore fuel when you can't see the road at 70 psi......fun watching though!

Jim

 

With a 913 pump you dont get any additional fuel with 18mm VS 21mm...its the timing and curve of the event...not the amount/volume

 

[quote author=Don M link=board=7;threadid=21630;start=15#msg203240 date=1067471562]
With a 913 pump you dont get any additional fuel with 18mm VS 21mm...its the timing and curve of the event...not the amount/volume


[/quote]

On Scheids and Daves Diesels stands we gained 210cc's @ 21mm rack with the same RPM. Exact same increase.

 

There are ways to increase the volume in the graduated cylinder with additional rack travel. What the engine gets and the injector will pass is totally different. Pop pressures on a calibration restrictor on the pump stand pop at 208 BAR VS 260 or more on a stock or performance injector. The volume of fuel that can pass through the calibration restrictor is wildy higher than even a modified performance injector can pass in the same unit time.

Most pump stands will not have the HP to crank over a P pump at full rack travel using a restriction at the end of the injection line the size of an actual injector. The calibration retrictor is easy to pump test oil through when compared. The numbers will go up considerably and trick many into thinking the fuel the truck/engine gets is the same

Another helper for the large numbers on a pump stand is the ID of the test line used for a pump stand and the 913 pump. It is 23% larger in diameter than a stock line on the Dodge/Cummins.

 

[quote author=Don M link=board=7;threadid=21630;start=15#msg203250 date=1067472813]
There are ways to increase the volume in the graduated cylinder with additional rack travel. What the engine gets and the injector will pass is totally different. Pop pressures on a calibration restrictor on the pump stand pop at 208 BAR VS 260 or more on a stock or performance injector. The volume of fuel that can pass through the calibration restrictor is wildy higher than even a modified performance injector can pass in the same unit time.

Most pump stands will not have the HP to crank over a P pump at full rack travel using a restriction at the end of the injection line the size of an actual injector. The calibration retrictor is easy to pump test oil through when compared. The numbers will go up considerably and trick many into thinking the fuel the truck/engine gets is the same

Another helper for the large numbers on a pump stand is the ID of the test line used for a pump stand and the 913 pump. It is 23% larger in diameter than a stock line on the Dodge/Cummins.




[/quote]

Nice post Don.

But there is still a gain @ 21mm rack over the first test at 18 mm of rack with no other changes.

I wonder what would happen to flow, pressure and timming if lines nearly twice the size of stock were used??

J.R.

 

There is a gain, but generally only on the stand.

In nearly all cases what is happening is: the pump is being asked to pump more fuel. This increases the parasitic drag, but unfortunantly the fuel cant be injected fast enough through the small diameter holes in the injector before the plunger begins to pass the spill port and cease the injection event. Then the plunger changes direction and actually creates a negative pressure or suction in its diameter.

So, you have a parasitic loss from pressurizing the fuel, but then cant get the gain from the additional fuel because (1) it is too late in the cycle to be burned with much efficiency and (2) the available unit time degrades to inject it in before the spill port uncovers.

On the larger line issue: I have run larger diameter lines for the past two years. Not radical. Pressure certainly drops, but volume left in the line for the next event is/has increased. it can be a good thing, but not for all cases and scenerios.

We tested tons of combos of line sizes and even lengths. All but a few combos failed. At least in the combo sets we tried.

Nathans truck has show a massive loss with most of the combos. Mine likes a few different sizes. Injector size, DV size and type, timing, etc effect the entire mess with massive mood swings. Too bad in my test cases anyway, I could not just slap on lines and make more power.

 

With all things being equal we did see a nice gain on the dyno.

Thanks for the disscusion...

 

Don and J.R. both, I have a set of .093 lines that I haven't dynoed with nor have I put back since the Canada trip but running around town before with them on the truck it was much more crisp on the throttle, problems was when I was at high altitude on the drive up north it made it grouchy on the cruise control so I pulled over and changed them back to the stock ones.

Jim

 

We tried the .093's = YUK. Tried .084 too = YUK.

Nathan tried them and it tanked on his 24 valve. Something like 16HP. Same dyno..one hour apart on the runs.
A unknown tried the 120's.....the worst yet.

Im back to the Top Secret size on mine. Plus 15HP

Dyno time pays dividends...now if I could convince everyone of this...we would all benefit.

Don~

 

this is one of the best threads i have read in a while, thanks for the info guys. mike