trinydex
02-19-2007, 12:33 AM
this thread is here to let people know that it's not as simple as what tha intanet tells you so. informed people please contribute.
For the record Precision injectors do not flow even close to the "claimed" & advertised ratings.
Any ECU reflash tuner with experience with Precision Injectors will tell you how far you will need to rescale these in order to bring them within the short term fuel trim "acceptable window".
It is very likely that our 845cc rated injectors will outflow Precision 880cc rated units.
I don't necessarily think the resellers mislead anyone. The problem lies in the manufacturer advertising xxx cc ratings. We have already determined a credible way to test them, which is via STFT logging with comparable injector scaling figures in the ECU programming,
Per rated cc, the PTE units use a smaller injector scaling number to set the stft correctly when reprogramming the ecu- therefore it can be understood they are over rated on their actual flow. There is your evidence. Whether you fully understand what I am trying to convey, is out of my hands.
"Better" really is not a correct statement. They both flow fuel and will run in the car. One set actually meets their advertised flow rating however.
The last set of 680 Precision injectors I installed and tuned, required that the injector scaling be left at the stock 513 in order not to run lean STFT.
Imagine if your 276 bhp rated Evo actually only put down an actual 180whp. I would be upset.
And FOR THE RECORD, claims of actual injector CCs are moot without knowing what duty cycles the vendor is actually testing them at. For example, RC and FIC use a 80% duty cycle for their ratings while Precision uses 85-90% duty cycles for their ratings. Hence the reason why the SAME Delphi injector gets rated differently between different vendors. However, I do agree that manufacturer advertised CC ratings can be misleading sometimes. The same part number from the same batch of injectors from Delphi advertised as 880cc might actually be flowing between 830cc-920cc. What's important is the customer take his vehicle to a knowledgable tuner to extract maximum HP while running safe duty cycles.
But this is not the thread to get into depth about this, so let's get back on topic. For anyone who wants to discuss injectors in greater detail, you can either PM, email, or post on this thread here: http://forums.evolutionm.net/showthread.php?t=238328
I don't mean to add more fuel to the injector rating fire, but I have what some might consider a decent bit of experience with different injectors, so I'll add my 1.9 cents for good measure. I'd post in that other thread, but this is where all the action is. ;)
Scott is right in the sense that the x80 injectors never flow that much.Â* They ALWAYS max out at numbers unusually similar to the x50 injectors. In other words, 780s for example will behave exactly like 750s from FIC. Additionally, when sending these injectors out to get flow tested, they always flow their rated value while static, or at 100% IDC. I have never seen an injector actually rated at a specific duty cycle... As far as the difference between the two rating systems, it was my understanding several years ago that FIC rated them at the same 43 psi we (and most other cars) run for base fuel pressure, while the x80 injectors were rated at 45 psi, hence the slightly higher reading.Â* When using these x80 injectors on a car with 43 psi base fuel pressure, they behave exactly like the x50s. :) There are other examples of injectors intended for american cars that are also rated at 45 psi, so it's not terribly uncommon, just fairly useless for us Mitsu owners.
Also, I'll back up what Scott is saying about closed loop behavior, the x80s act like x50s in this case as well, though not always to the same degree of accuracy as the static numbers. Anyone that has done any appreciable amount of tuning with both injector types, on just about any system, can attest to this.
Additionally, while the stock injectors are rated at 560cc, they behave very much like 580s. For whatever that's worth; it's a relatively small difference. As far as using them with an EVO Green/20g-LT, that's a negative, as mentioned earlier. The stock 8 and 9 turbos will put the stock injectors at 100% IDC at 11:1 with pump gas (specific gravity around .76). The EVO green maxed out under the same conditions would put them at 119% IDC. ;)Â* Of course you won't max out a Green on pump gas, but you get the point. Actually, before someone asks, with an AFR of 12:1 and race gas with a SG of .72, you would be at 115%. And before someone else asks, I've tested the formula I use to arrive at these numbers on my 2g, EVO, and many other cars, and found them to be accurate to within about .2 for IDC, AFR, and airflow in lbs (whatever variable I am trying to solve for).Â*
I have nothing for or against either shop, I've done business with neither of them.Â* I'm simply trying to relay some of my personal experiences with both types of injectors for the good of the community. :D
If rescaling injectors was only as easy as plugging in the advertised static flow capacity.Â* Unfortunately, it isn't that simple due to variances in latency - the 'other' dimension to injector characteristics.
the moral that i gather from this reading is that in the end how your injectors are rescaled and the amount of safety margin is determined by experience with the product. this means consult with your tuner. it don't matter if one person is right or wrong... if they've done the work with the product before... and they're doin' the knobbin' on your car... let them do the do. it don't help to argue about intanet and number technicalities, what helps is sourcing a person that knows what they're doin' AT LEAST with the set up you're planning or that they're planning for you.
For the record Precision injectors do not flow even close to the "claimed" & advertised ratings.
Any ECU reflash tuner with experience with Precision Injectors will tell you how far you will need to rescale these in order to bring them within the short term fuel trim "acceptable window".
It is very likely that our 845cc rated injectors will outflow Precision 880cc rated units.
I don't necessarily think the resellers mislead anyone. The problem lies in the manufacturer advertising xxx cc ratings. We have already determined a credible way to test them, which is via STFT logging with comparable injector scaling figures in the ECU programming,
Per rated cc, the PTE units use a smaller injector scaling number to set the stft correctly when reprogramming the ecu- therefore it can be understood they are over rated on their actual flow. There is your evidence. Whether you fully understand what I am trying to convey, is out of my hands.
"Better" really is not a correct statement. They both flow fuel and will run in the car. One set actually meets their advertised flow rating however.
The last set of 680 Precision injectors I installed and tuned, required that the injector scaling be left at the stock 513 in order not to run lean STFT.
Imagine if your 276 bhp rated Evo actually only put down an actual 180whp. I would be upset.
And FOR THE RECORD, claims of actual injector CCs are moot without knowing what duty cycles the vendor is actually testing them at. For example, RC and FIC use a 80% duty cycle for their ratings while Precision uses 85-90% duty cycles for their ratings. Hence the reason why the SAME Delphi injector gets rated differently between different vendors. However, I do agree that manufacturer advertised CC ratings can be misleading sometimes. The same part number from the same batch of injectors from Delphi advertised as 880cc might actually be flowing between 830cc-920cc. What's important is the customer take his vehicle to a knowledgable tuner to extract maximum HP while running safe duty cycles.
But this is not the thread to get into depth about this, so let's get back on topic. For anyone who wants to discuss injectors in greater detail, you can either PM, email, or post on this thread here: http://forums.evolutionm.net/showthread.php?t=238328
I don't mean to add more fuel to the injector rating fire, but I have what some might consider a decent bit of experience with different injectors, so I'll add my 1.9 cents for good measure. I'd post in that other thread, but this is where all the action is. ;)
Scott is right in the sense that the x80 injectors never flow that much.Â* They ALWAYS max out at numbers unusually similar to the x50 injectors. In other words, 780s for example will behave exactly like 750s from FIC. Additionally, when sending these injectors out to get flow tested, they always flow their rated value while static, or at 100% IDC. I have never seen an injector actually rated at a specific duty cycle... As far as the difference between the two rating systems, it was my understanding several years ago that FIC rated them at the same 43 psi we (and most other cars) run for base fuel pressure, while the x80 injectors were rated at 45 psi, hence the slightly higher reading.Â* When using these x80 injectors on a car with 43 psi base fuel pressure, they behave exactly like the x50s. :) There are other examples of injectors intended for american cars that are also rated at 45 psi, so it's not terribly uncommon, just fairly useless for us Mitsu owners.
Also, I'll back up what Scott is saying about closed loop behavior, the x80s act like x50s in this case as well, though not always to the same degree of accuracy as the static numbers. Anyone that has done any appreciable amount of tuning with both injector types, on just about any system, can attest to this.
Additionally, while the stock injectors are rated at 560cc, they behave very much like 580s. For whatever that's worth; it's a relatively small difference. As far as using them with an EVO Green/20g-LT, that's a negative, as mentioned earlier. The stock 8 and 9 turbos will put the stock injectors at 100% IDC at 11:1 with pump gas (specific gravity around .76). The EVO green maxed out under the same conditions would put them at 119% IDC. ;)Â* Of course you won't max out a Green on pump gas, but you get the point. Actually, before someone asks, with an AFR of 12:1 and race gas with a SG of .72, you would be at 115%. And before someone else asks, I've tested the formula I use to arrive at these numbers on my 2g, EVO, and many other cars, and found them to be accurate to within about .2 for IDC, AFR, and airflow in lbs (whatever variable I am trying to solve for).Â*
I have nothing for or against either shop, I've done business with neither of them.Â* I'm simply trying to relay some of my personal experiences with both types of injectors for the good of the community. :D
If rescaling injectors was only as easy as plugging in the advertised static flow capacity.Â* Unfortunately, it isn't that simple due to variances in latency - the 'other' dimension to injector characteristics.
the moral that i gather from this reading is that in the end how your injectors are rescaled and the amount of safety margin is determined by experience with the product. this means consult with your tuner. it don't matter if one person is right or wrong... if they've done the work with the product before... and they're doin' the knobbin' on your car... let them do the do. it don't help to argue about intanet and number technicalities, what helps is sourcing a person that knows what they're doin' AT LEAST with the set up you're planning or that they're planning for you.