Back when we did this stroker the owner bought some DDP 50hp tips. Now everybody is using % instead of hp. So what and how do we figure out what % we are at?
Injector % question.
- Thread starter 68skylark455
- Start date
i was always under the impression that the % is the increase in hole size over the stock holes in the injector tips or the flow over the stock nozzles. i dont think you can put a hp rating on injectors because there is too many tuning variables to make a solid hp # claim, unless its a stock tune truck with just upgraded larger injector nozzles and nothing else done.
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Yupper, percentage of hole size increase, but yes too, HP will vary so not set in stone, more of a ballpark figure if you will Stock LB7 nozzles you gotta look pretty close to see the holes but the 50% are much easier to see! IIRC, the EDM process uses tiny fine carbon filiments under a dielectric fluid enviroment to burn the holes through, correct me if im wrong, but prolly hard/expensive to get a finer variance of electrodes VS time on an extrudehoning maching pumping an abrasive fluid for a given amount of time to achive desired enlargmentJust feelin philosophical tonight i guess:happy2:
Sorry to ask and then abandon the thread, have alot going on with the supercharger and challenger saga .
From what everyone has said ours are too small I am guessing. What is a good % to go with for a daily driven, daily towing 7.1? Guy suggested 60% if we do the empire charger kit but if we don't are we ok or should we go big or go home?
I am still learning and I greatly appreciate everyone's help and tech info. I would be lost without Pat, Kat, Guy, Larry Jewell and so many others. Thank you.
.From what everyone has said ours are too small I am guessing. What is a good % to go with for a daily driven, daily towing 7.1? Guy suggested 60% if we do the empire charger kit but if we don't are we ok or should we go big or go home?
I am still learning and I greatly appreciate everyone's help and tech info. I would be lost without Pat, Kat, Guy, Larry Jewell and so many others. Thank you.
If it were me i would just listen to guy. IMOP. But now i wish i would have just gotten the 100% sticks. Ima a go big or go home type of guy.:happy2:
You haven't told us the most important thing..... What size charger(s) you are going to run. I would imagine due to larger displacement that the 7.1 needs more fuel than the 6.6. When i talked to guy trippin a few weeks ago he said that his cam produced wonderful low end power and it really helped get things rolling and building boost easier. I know that was for the 6.6 but IMO i think his cam for the 7.1 would be the same way so i wouldn't go to large. And also i would also always like to go a little to big and then tune it out the smoke because that gives you room to grow. BUT not too big because then you'll have a weird idle and stuff.
Old school/mechanically injected diesel guys would refer to injectors in increases of hp, because that's all they had to increase power. The old school injector shops just naturally continue to do it that way.
Next is the shops that refer to injectors size as an % increase in hole size, which tells us nothing about flow. They have to do it this way because they have no way to actually flow test the injector properly. If you look at a Holley carb jet sheet you will find many jets that are the same size but flow differently and that is at far less pressure than what we are dealing with. Entrances and exits to an orifice can drastically alter the flow characteristics.
Expressing injectors as a % of flow in mm3 over stock at wide open throttle fuel pressures and pulse widths seems to be a more accurate way to rate injectors. And it relates nicely to the tables in EFILive.
Next is the shops that refer to injectors size as an % increase in hole size, which tells us nothing about flow. They have to do it this way because they have no way to actually flow test the injector properly. If you look at a Holley carb jet sheet you will find many jets that are the same size but flow differently and that is at far less pressure than what we are dealing with. Entrances and exits to an orifice can drastically alter the flow characteristics.
Expressing injectors as a % of flow in mm3 over stock at wide open throttle fuel pressures and pulse widths seems to be a more accurate way to rate injectors. And it relates nicely to the tables in EFILive.
It has the GT42Mag on it.There are so many changes I made its really hard to remember. The inlet to the Y-bridge is now 3", it has the PPE dual fueler, fass 95, banks intercooler and tubes, headers with matched up-pipes, So-Cal cam, stage 2 heads, still thinking I missed something. I was just wanting to give him the best without over doing it, he drives this thing everywhere but its usually 12+ hours away from me so I am trying to keep it simple. I haven't even messed with the first tune Pat did for me. We have a DSP5 so I can always save a safe tune for him to drive it normally. Just looking at my options. And I have always trusted Guy and Pat's opinions, they have helped me more times then I can count. I am sure they now have caller id just for me!
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given that information i look at well people With VNT turbos like the cheetah and danville are using 45%. Then the guys running twins with i think a GT45?? are running anywhere from 25% to 35% due to the fast act of spooling is already there. I would say 50% to 60% would be about right. That is just with me comparing other peoples setups and things. Not that i am all knowing. Wish i was but i am still learning. Just my two cents. :baby:
I have done a little bit of everything with my 45% overs and it seems to be a good size , a little harder to tune smoke out when towing and under 5 p.s.i boost but other than that it is every bit as drivable as it was before and even seems to spool a bit faster because it a little easier to build heat . In that build Larry i would go 60% overs , If you go with the SC it will have no problem cleaning up smoke in the lower RPM's
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Old school/mechanically injected diesel guys would refer to injectors in increases of hp, because that's all they had to increase power. The old school injector shops just naturally continue to do it that way.
Next is the shops that refer to injectors size as an % increase in hole size, which tells us nothing about flow. They have to do it this way because they have no way to actually flow test the injector properly. If you look at a Holley carb jet sheet you will find many jets that are the same size but flow differently and that is at far less pressure than what we are dealing with. Entrances and exits to an orifice can drastically alter the flow characteristics.
Expressing injectors as a % of flow in mm3 over stock at wide open throttle fuel pressures and pulse widths seems to be a more accurate way to rate injectors. And it relates nicely to the tables in EFILive.
Thanks Guy. I've seen so many different posts and they present the injector size differently so it's truly difficult to figure out what FLOW they are using.
Thanks
David
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I will probably just go with the 60%. I will have to buy a used set and send them off to Exergy to have it done as I never get the truck long enough to remove them and wait for it to be done. As soon as I fix the front suspension problems I will get him to spring for some bigger injectors.
Your in good hands if you go with Dynomite or Exergy. If you are leaning towards one of our procharger kits more is better.