264/264's without injectors
Originally Posted by shiv@vishnu
Robi, could you kindly explain what these possible "hiccups" are and if/how they (the "hiccups") are more likely to happen to OE injectors than aftermarket replacements?
shiv
shiv
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From: Danville/Blackhawk, California
Originally Posted by robi
Buschurs first step is to 680cc that gives you room to mod to about 400 whp with lower than 90% IDC if funds are limited getting past 400 WHP should give you lots of time on your 680's
my 2c,
shiv
I've said this elsewhere and I'll say it here...
It's commonly accepted knowledge that pintel type injectors will go semi-static at ~85% IDC and disc type injectors go static at ~90% IDC. As I understand it, in a semi-static condition the injector flows at 50% of it's rated capacity. Of course the injector goes semi-static at the very worst of times: at wide open throttle, at full boost and at or near redline. When one of your injectors goes static under those conditions, sooner or later... BOOM! Why risk it to "save" $500?
It's commonly accepted knowledge that pintel type injectors will go semi-static at ~85% IDC and disc type injectors go static at ~90% IDC. As I understand it, in a semi-static condition the injector flows at 50% of it's rated capacity. Of course the injector goes semi-static at the very worst of times: at wide open throttle, at full boost and at or near redline. When one of your injectors goes static under those conditions, sooner or later... BOOM! Why risk it to "save" $500?
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From: Danville/Blackhawk, California
Originally Posted by propellerhead
I've said this elsewhere and I'll say it here...
It's commonly accepted knowledge that pintel type injectors will go semi-static at ~85% IDC and disc type injectors go static at ~90% IDC. As I understand it, in a semi-static condition the injector flows at 50% of it's rated capacity. Of course the injector goes semi-static at the very worst of times: at wide open throttle, at full boost and at or near redline. When one of your injectors goes static under those conditions, sooner or later... BOOM! Why risk it to "save" $500?
It's commonly accepted knowledge that pintel type injectors will go semi-static at ~85% IDC and disc type injectors go static at ~90% IDC. As I understand it, in a semi-static condition the injector flows at 50% of it's rated capacity. Of course the injector goes semi-static at the very worst of times: at wide open throttle, at full boost and at or near redline. When one of your injectors goes static under those conditions, sooner or later... BOOM! Why risk it to "save" $500?
It is also commonly accepted that turbo engines run at a BSFC of .55-.6 which is, to say the least, inaccurate. Injector sizing guidelines are just that, guidelines set for by fuel injector manufacturers. They are based in reality but tend to err on the side of conservatism both in terms of the IDC in which the injectors runs static and their flow behavior during a semi-static state. That said, the factory peak and hold injector is perfectly consistent operating to approx 95% without any abberations in fuel flow or spray pattern. Given the choice between an OE injector that is perfectly suited to support the flow capacity of the OE turbo and a "modified" stocker designed to flow 40% than one will ever need (with the stock turbo, of course) i'll go with OE any day of the week.
Historically, i've been known to be pretty conservative when upgrading fuel systems and I don't think what I'm saying know is in opposition to that. But it's important to separate fact from fiction which is purpose of a discussion forum. There is certainly no harm in using larger than necessary injectors. It's certainly not going to harm performance or drivability as long as the necessary engine controls are in place. But I don't want others to fall prey to the notion that something needs to be upgraded for safety's sake when this is not the case.
my 2c,
Shiv
To answer the original question you are safe on your stock injectors.
To comment on Shiv's comment... we still offer the 680 injectors with the Super AFC and a manual boost controller. Doesn't just work in the DSM world, works great on the EVO's also. The larger injectors will not only help get rid of fuel cut (via. AFC tuning) it also advances the engine timing through leaning out the AFC. win-win.
Before some sorry reasons not to do this get pointed out, whatever may come up, it works and works well. I know of not one single person who has hurt their EVO doing this and it makes excellent power. I can't even count the guys going low 12's and even high 11's with this combination at this point.
David Buschur
www.buschurracing.com
To comment on Shiv's comment... we still offer the 680 injectors with the Super AFC and a manual boost controller. Doesn't just work in the DSM world, works great on the EVO's also. The larger injectors will not only help get rid of fuel cut (via. AFC tuning) it also advances the engine timing through leaning out the AFC. win-win.
Before some sorry reasons not to do this get pointed out, whatever may come up, it works and works well. I know of not one single person who has hurt their EVO doing this and it makes excellent power. I can't even count the guys going low 12's and even high 11's with this combination at this point.
David Buschur
www.buschurracing.com
Originally Posted by shiv@vishnu
It is also commonly accepted that turbo engines run at a BSFC of .55-.6 which is, to say the least, inaccurate. Injector sizing guidelines are just that, guidelines set for by fuel injector manufacturers. They are based in reality but tend to err on the side of conservatism both in terms of the IDC in which the injectors runs static and their flow behavior during a semi-static state. That said, the factory peak and hold injector is perfectly consistent operating to approx 95% without any abberations in fuel flow or spray pattern. Given the choice between an OE injector that is perfectly suited to support the flow capacity of the OE turbo and a "modified" stocker designed to flow 40% than one will ever need (with the stock turbo, of course) i'll go with OE any day of the week.
Historically, i've been known to be pretty conservative when upgrading fuel systems and I don't think what I'm saying know is in opposition to that. But it's important to separate fact from fiction which is purpose of a discussion forum. There is certainly no harm in using larger than necessary injectors. It's certainly not going to harm performance or drivability as long as the necessary engine controls are in place. But I don't want others to fall prey to the notion that something needs to be upgraded for safety's sake when this is not the case.
my 2c,
Shiv
Historically, i've been known to be pretty conservative when upgrading fuel systems and I don't think what I'm saying know is in opposition to that. But it's important to separate fact from fiction which is purpose of a discussion forum. There is certainly no harm in using larger than necessary injectors. It's certainly not going to harm performance or drivability as long as the necessary engine controls are in place. But I don't want others to fall prey to the notion that something needs to be upgraded for safety's sake when this is not the case.
my 2c,
Shiv
I'm not suggesting that the guy who started this thread has to automatically upgrade his injectors just because he installed 264s. What I'm suggesting is that with relatively few mods and a less than judicious twist of the boost controller, your average punter could very well be running *well* above 95% IDC. This will almost inevitably occur if he's had his rev limit raised and he's out at the track running "race gas" with the boost cranked to 22 or 23 psi. What does it take for the OEM injectors go static when being run for extended periods at 100% IDC?
In my very limited personal experience, with stock turbo, 3" TB exhaust & 264 cams, the stock injectors and fuel system can pump enough fuel (even if pooling it on the backs of the valves) to maintain very rich AFRs (10.5-10.8). However, when doing so I was seeing 99.5% IDC somewhere above 7000rpm. I'd have to go back and check my logs to figure out exactly where I was crossing the threshold.
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Injector size
IIRC even if an injector goes static that doesnt stop an increase in fuel flow (I think you can change duration too). There's a lot of different styles, some like to run the 85% or some percentage, others get close to but not over, and others prefer to run 100% and use other methods. There's also a small percentage that affects flow too I think - that's the amount of time to open and close the injector and the fuel ramp up and down during those blips. It seems to be not such a fearful ceiling number IMO.
The same kind of hiccups that can happen to the fuel pump...On paper the stock fuel pump "should" handle every thing you can throw at it...but everyone (including you I think) asks owners who mod their cars to do this upgrade "to be safe". Imho whenever you drive something mechanical to the absolute limit you are asking for something... anything to "have a bad day" and cause a faiure elsewhere. I also said this guy can do as he pleases I just wouldn't and have increased the injectorsize as I have modded my car. PS during the SCC USCC Scot Gray had an injector go flaky on him...(1000cc) would only flow 50%. The reserve built in kept his motor alive instead of eating a piston. That night he diagnosed it and replaced the whole set inorder to finish the competition. I feel that the OE's are just fine, just running them so close to the line is asking for Murphy to ruin your trackday. Shiv of course everyone on EVOM knows you know better than RRE, Buschur Racing, Pruven Performance, Sparco/apexi, XS Engineering, AMS, Magnus....need I go on? They ALL recomend going to larger ingectors EARLY in their mod sequence. Guess we're all wrong on this one.
Originally Posted by davidbuschur
To answer the original question you are safe on your stock injectors.
To comment on Shiv's comment... we still offer the 680 injectors with the Super AFC and a manual boost controller. Doesn't just work in the DSM world, works great on the EVO's also. The larger injectors will not only help get rid of fuel cut (via. AFC tuning) it also advances the engine timing through leaning out the AFC. win-win.
Before some sorry reasons not to do this get pointed out, whatever may come up, it works and works well. I know of not one single person who has hurt their EVO doing this and it makes excellent power. I can't even count the guys going low 12's and even high 11's with this combination at this point.
David Buschur
www.buschurracing.com
To comment on Shiv's comment... we still offer the 680 injectors with the Super AFC and a manual boost controller. Doesn't just work in the DSM world, works great on the EVO's also. The larger injectors will not only help get rid of fuel cut (via. AFC tuning) it also advances the engine timing through leaning out the AFC. win-win.
Before some sorry reasons not to do this get pointed out, whatever may come up, it works and works well. I know of not one single person who has hurt their EVO doing this and it makes excellent power. I can't even count the guys going low 12's and even high 11's with this combination at this point.
David Buschur
www.buschurracing.com
I generally try to stay with the stock injector in a car as long as I can. The EVO has a large enough injector that 400 whp is not a problem on them. In the case of the EVO though we ran into fuel cut early on with the car. At the time the only way around it was to install a larger injector in the car and then pull the fuel back out with the AFC. This keeps the car from hitting fuel cut, you are basically tricking it into thinking it has less air coming in.
Now that we have other options available for tuning, like the flash, EMS and V Pro that completely eliminate the fuel cut there is no need to run the large injector outlined in our Stage 4 until you upgrade the turbo.
David Buschur
www.buschurracing.com
Now that we have other options available for tuning, like the flash, EMS and V Pro that completely eliminate the fuel cut there is no need to run the large injector outlined in our Stage 4 until you upgrade the turbo.
David Buschur
www.buschurracing.com
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From: Danville/Blackhawk, California
Originally Posted by propellerhead
At what point do you decide to upgrade injectors? What criteria needs to be met? I'm not trying to be antagonistic, I'm sincerely interested.
I'm not suggesting that the guy who started this thread has to automatically upgrade his injectors just because he installed 264s. What I'm suggesting is that with relatively few mods and a less than judicious twist of the boost controller, your average punter could very well be running *well* above 95% IDC. This will almost inevitably occur if he's had his rev limit raised and he's out at the track running "race gas" with the boost cranked to 22 or 23 psi. What does it take for the OEM injectors go static when being run for extended periods at 100% IDC?
In my very limited personal experience, with stock turbo, 3" TB exhaust & 264 cams, the stock injectors and fuel system can pump enough fuel (even if pooling it on the backs of the valves) to maintain very rich AFRs (10.5-10.8). However, when doing so I was seeing 99.5% IDC somewhere above 7000rpm. I'd have to go back and check my logs to figure out exactly where I was crossing the threshold.
I'm not suggesting that the guy who started this thread has to automatically upgrade his injectors just because he installed 264s. What I'm suggesting is that with relatively few mods and a less than judicious twist of the boost controller, your average punter could very well be running *well* above 95% IDC. This will almost inevitably occur if he's had his rev limit raised and he's out at the track running "race gas" with the boost cranked to 22 or 23 psi. What does it take for the OEM injectors go static when being run for extended periods at 100% IDC?
In my very limited personal experience, with stock turbo, 3" TB exhaust & 264 cams, the stock injectors and fuel system can pump enough fuel (even if pooling it on the backs of the valves) to maintain very rich AFRs (10.5-10.8). However, when doing so I was seeing 99.5% IDC somewhere above 7000rpm. I'd have to go back and check my logs to figure out exactly where I was crossing the threshold.
I can't speak for everyone, but I tend to upgrade injectors when i feel that control over fueling is compromised. Be careful to derive actual duty cycle from what obd-II loggers suggest as they often apply mathematics which don't always comply with applied reality. They are good to use for comparison purposes but not good when it comes to relying on absolute IDC values.
How is a loss of fuel control quantified? Usually on the dyno (engine or chassis) when the engine loaded to max load at peak hp. This is usually around the point of peak hp. The cause of a static injector condition is when the rest period between injector openings isn't long enough so that it doesn't close fully between injector events. This point is due to mechanical limitations is influenced by fuel pressure, duty cycle and system voltage. All of which are consistent during the life of the injector. On the dyno, it is easy to identify a static condition by simply triming fuel in both directions and ensuring that there is a commensurate change in registered AFR. Transient static conditions (with one or more injector) can easily be recoginized by sudden drops in AFR. On an intertial dyno (dynojet, for instance), this is a bit tricker to diagnose. What you look for a point in the AFR trace in which AFRs drop 0.5 points or so and then take a diagnal and straight direction upwards as RPMs rise. The sudden drop is the injector suddenly going wide open/static. The straight diagnal line from there upwards is the AFR getting leaner (fuel flow remains constant) but airflow increasing (as RPM rises). During this time, there is a complete loss of injector control. Often, it would take a ~10-15% negative trim of fuel to restore fuel control (along with a 0.5 point leaner AFR of course).
Dave B. says...
Now that we have other options available for tuning, like the flash, EMS and V Pro that completely eliminate the fuel cut there is no need to run the large injector outlined in our Stage 4 until you upgrade the turbo.
Regards,
shiv
Originally Posted by shiv@vishnu
Hi,
I can't speak for everyone, but I tend to upgrade injectors when i feel that control over fueling is compromised. Be careful to derive actual duty cycle from what obd-II loggers suggest as they often apply mathematics which don't always comply with applied reality. They are good to use for comparison purposes but not good when it comes to relying on absolute IDC values.
How is a loss of fuel control quantified? Usually on the dyno (engine or chassis) when the engine loaded to max load at peak hp. This is usually around the point of peak hp. The cause of a static injector condition is when the rest period between injector openings isn't long enough so that it doesn't close fully between injector events. This point is due to mechanical limitations is influenced by fuel pressure, duty cycle and system voltage. All of which are consistent during the life of the injector. On the dyno, it is easy to identify a static condition by simply triming fuel in both directions and ensuring that there is a commensurate change in registered AFR. Transient static conditions (with one or more injector) can easily be recoginized by sudden drops in AFR. On an intertial dyno (dynojet, for instance), this is a bit tricker to diagnose. What you look for a point in the AFR trace in which AFRs drop 0.5 points or so and then take a diagnal and straight direction upwards as RPMs rise. The sudden drop is the injector suddenly going wide open/static. The straight diagnal line from there upwards is the AFR getting leaner (fuel flow remains constant) but airflow increasing (as RPM rises). During this time, there is a complete loss of injector control. Often, it would take a ~10-15% negative trim of fuel to restore fuel control (along with a 0.5 point leaner AFR of course).
Regards,
shiv
I can't speak for everyone, but I tend to upgrade injectors when i feel that control over fueling is compromised. Be careful to derive actual duty cycle from what obd-II loggers suggest as they often apply mathematics which don't always comply with applied reality. They are good to use for comparison purposes but not good when it comes to relying on absolute IDC values.
How is a loss of fuel control quantified? Usually on the dyno (engine or chassis) when the engine loaded to max load at peak hp. This is usually around the point of peak hp. The cause of a static injector condition is when the rest period between injector openings isn't long enough so that it doesn't close fully between injector events. This point is due to mechanical limitations is influenced by fuel pressure, duty cycle and system voltage. All of which are consistent during the life of the injector. On the dyno, it is easy to identify a static condition by simply triming fuel in both directions and ensuring that there is a commensurate change in registered AFR. Transient static conditions (with one or more injector) can easily be recoginized by sudden drops in AFR. On an intertial dyno (dynojet, for instance), this is a bit tricker to diagnose. What you look for a point in the AFR trace in which AFRs drop 0.5 points or so and then take a diagnal and straight direction upwards as RPMs rise. The sudden drop is the injector suddenly going wide open/static. The straight diagnal line from there upwards is the AFR getting leaner (fuel flow remains constant) but airflow increasing (as RPM rises). During this time, there is a complete loss of injector control. Often, it would take a ~10-15% negative trim of fuel to restore fuel control (along with a 0.5 point leaner AFR of course).
Regards,
shiv
Smogrunner: "Gee Shiv, are you an expert tuner?"
Shiv: "Why no, but I did stay at the New Dehli Holiday Inn last night."
J/K Shiv. Have fun vacationing in India.
Last edited by Smogrunner; Oct 11, 2004 at 08:45 PM.
Originally Posted by Smogrunner
Smogrunner: "Gee Shiv, are you an expert tuner?"
Shiv: "Why no, but I did stay at the New Dehli Holiday Inn last night."
J/K Shiv. Have fun vacationing in India.
Shiv: "Why no, but I did stay at the New Dehli Holiday Inn last night."
J/K Shiv. Have fun vacationing in India.
