6.0 liter update, checking a few things
02-06-2012, 05:33 PM
#16
Rennlist Member
Thread Starter
chuck, get a clue would you. i have a race car , and is and has been tuned just as Anderson has tuned his for many years. stock stuff, and just fuel regulator adjustment, and lots of dyno work. i havent "bludgenoned"anything. I have a well running 928 racer with safe fuel mixture and maybe leaving 20h on the table with a good tune . Bill went for a ride with me, we leaned a stock ecu out and did some runs, it was very close to what i have now. it only got slow when we leaned it way out. no pings either.
did i mentioned ive beat on this engine for 4 years now and 8 years before that , logging more real races than anyone here. so , onece you are able to read, comprehend and understand what the heck i am doing, you then can post a useful comment.
some errors in your report above. no, the vaccum line on the fuel regs is for pulling back fuel at idle. the actual pressure of the fuel rail lines will be measured accurately by the guage. I run it with no vaccum and witih vacuum to make sure its all functioning well. yes, you are guesing how the RRFP works. it uses vacuum to pull the diaprham to back to let fuel back to the tank, but its not a 1:1 relationshiop. its like 3-4psi.if what you say is correct, when you reve the engine, and get negagive, 10 to 12psi (vacuum) you would see the pressure jump by that much and that doesnt happen.
#, read title above, this is NOT my car. im reporting what i have found, trying to help a friend who owns it and get it back in heathy , or to a heathly running conditions. I DONT HAVE the ability to use a sharktunier with my car, although we used Bill Ball and Johns set up to do some testing, only proving my car is running pretty well as it is now, but could be optimized. remmber, ive been on the dyno a lot over the past 12 years with this car. the fuel ratios are safe, not optimized. now THIS car is way , welll , out of wack! 18 to 20psi is the range of pressure on the gauge . is so low, i thought it was leaking.
its the real deal. either the owner was trying to lean it out or richen it up over the years, and got a real wrong pressure. he has been driving it for longer than most any 6 liter in the world, as this is devek's first engine.(well , second as the original had some issues and this one was rebult ) it also is fairly high compression, as they shaved the heads to get rid of some warpring. 
now, the tail pipe is black, so im wondering what the fuel is really doing , as i have only floored this car from 60 to 80 twice since ive driven it, and its not fast, but its not slow either. i dont hear it pining, but will probably put my air fuel ratio guage to see where we are. by the way, Billl and i did this on my car to coorelate the wide band with what i have on the car all the time. its a very good ball park guage and way of making sure the car is at least safe.
so, the reason i posted this anyway was to see if anyone has seen a car run at that low of a pressure.
it could also be the reason that it runs so crappy on hot start.
ask anyone that has raced against me, how well MY car is tuned. it runs great. it might need some optimization to take full advantage of the 6.5 liter, but my bet is the LIST that recommended the much larger injectors is at fault for a car that could be running better. if i did what i wanted, i would have the 24lb injectors, knowing that the stock S4 stuff on a 6.5 liter wouldnt be able to make over 400rwhp on a good day, and like john says, i would rather have 70psi pressures on a 85 injector , .like i had on the S4 injectors , than 44psi on an injector i could "grow" into when i had the cash to put on the CF Intake.
did i mentioned ive beat on this engine for 4 years now and 8 years before that , logging more real races than anyone here. so , onece you are able to read, comprehend and understand what the heck i am doing, you then can post a useful comment.
The fuel pressure that is "felt" by an injector is the difference between rail pressure and intake pressure (vacuum). That's why there is a vacuum line on the fuel-pressure regulator (and dampers). The stock LH tune is based on an injector pressure of 55 psi.
Fuel pressure measured with a gauge is called "gauge pressure", i.e. relative to atmosphere. To make it meaningful, measure with the engine off (and manifold at atmospheric), and fuel-pump jumpered. Always. Numbers quoted with engine running are meaningless.
For example, if your intake vacuum is 7psi, then your 18psi gauge pressure is really 25psi injector pressure-- but I am guessing.
In any event, that is stupid-low. As John says, injectors don't work well at low pressure, and you are very far from the factory tune... basically wandering around in the woods at midnight with no flashlight.
How can you adjust fuel pressure without a gauge? (I know, with a wrench...).
If you are hearing pings then you are damaging the engine. And why would pulling pressure out help with pinging??
Yep. Although the pinging is more likely higher-than-stock compression, with stock ignition maps.
A couple... There is a tool which can be connected to your engine and will tell you whether your fueling is rich or lean, and by how much, and let you log that data while you drive. It will allow you set the injector size properly, and let you change the maps for any RPM and load, and properly compensate for engine temperature for warmup. It will also report on the EZK's knock-retard, how much and which cylinders, and allow you to set the ignition advance for any load and RPM. Knowing when and where the EZK is retarding timing is extremely valuable information, and staying within the EZK's retard range is critical. You can log all that data, for hours at a time if you want, and take it home and tweak your ignition and fuel maps with a few keystrokes. In addition, having access to the ignition maps also means you can set up one map for race gas with more aggressive timing, and another for street gas-- just wire a switch to the coding plug.
Considering all that you have invested in the engine and your car, in terms of money, sweat and passion, how can you not have one of these tools? It is called a Sharktuner, designed by a couple of very clever guys in the UK, and available for a pittance, considering all that it does.
[Edit: I understand that this isn't your car, but my point stands: You need a Sharktuner for your own car, and an extra pair of PEM's for this car].
Fuel pressure measured with a gauge is called "gauge pressure", i.e. relative to atmosphere. To make it meaningful, measure with the engine off (and manifold at atmospheric), and fuel-pump jumpered. Always. Numbers quoted with engine running are meaningless.
For example, if your intake vacuum is 7psi, then your 18psi gauge pressure is really 25psi injector pressure-- but I am guessing.
In any event, that is stupid-low. As John says, injectors don't work well at low pressure, and you are very far from the factory tune... basically wandering around in the woods at midnight with no flashlight.
How can you adjust fuel pressure without a gauge? (I know, with a wrench...).
If you are hearing pings then you are damaging the engine. And why would pulling pressure out help with pinging??
Yep. Although the pinging is more likely higher-than-stock compression, with stock ignition maps.
A couple... There is a tool which can be connected to your engine and will tell you whether your fueling is rich or lean, and by how much, and let you log that data while you drive. It will allow you set the injector size properly, and let you change the maps for any RPM and load, and properly compensate for engine temperature for warmup. It will also report on the EZK's knock-retard, how much and which cylinders, and allow you to set the ignition advance for any load and RPM. Knowing when and where the EZK is retarding timing is extremely valuable information, and staying within the EZK's retard range is critical. You can log all that data, for hours at a time if you want, and take it home and tweak your ignition and fuel maps with a few keystrokes. In addition, having access to the ignition maps also means you can set up one map for race gas with more aggressive timing, and another for street gas-- just wire a switch to the coding plug.
Considering all that you have invested in the engine and your car, in terms of money, sweat and passion, how can you not have one of these tools? It is called a Sharktuner, designed by a couple of very clever guys in the UK, and available for a pittance, considering all that it does.
[Edit: I understand that this isn't your car, but my point stands: You need a Sharktuner for your own car, and an extra pair of PEM's for this car].
some errors in your report above. no, the vaccum line on the fuel regs is for pulling back fuel at idle. the actual pressure of the fuel rail lines will be measured accurately by the guage. I run it with no vaccum and witih vacuum to make sure its all functioning well. yes, you are guesing how the RRFP works. it uses vacuum to pull the diaprham to back to let fuel back to the tank, but its not a 1:1 relationshiop. its like 3-4psi.if what you say is correct, when you reve the engine, and get negagive, 10 to 12psi (vacuum) you would see the pressure jump by that much and that doesnt happen.
#, read title above, this is NOT my car. im reporting what i have found, trying to help a friend who owns it and get it back in heathy , or to a heathly running conditions. I DONT HAVE the ability to use a sharktunier with my car, although we used Bill Ball and Johns set up to do some testing, only proving my car is running pretty well as it is now, but could be optimized. remmber, ive been on the dyno a lot over the past 12 years with this car. the fuel ratios are safe, not optimized. now THIS car is way , welll , out of wack! 18 to 20psi is the range of pressure on the gauge . is so low, i thought it was leaking.
its the real deal. either the owner was trying to lean it out or richen it up over the years, and got a real wrong pressure. he has been driving it for longer than most any 6 liter in the world, as this is devek's first engine.(well , second as the original had some issues and this one was rebult ) it also is fairly high compression, as they shaved the heads to get rid of some warpring. now, the tail pipe is black, so im wondering what the fuel is really doing , as i have only floored this car from 60 to 80 twice since ive driven it, and its not fast, but its not slow either. i dont hear it pining, but will probably put my air fuel ratio guage to see where we are. by the way, Billl and i did this on my car to coorelate the wide band with what i have on the car all the time. its a very good ball park guage and way of making sure the car is at least safe.
so, the reason i posted this anyway was to see if anyone has seen a car run at that low of a pressure.
it could also be the reason that it runs so crappy on hot start.
ask anyone that has raced against me, how well MY car is tuned. it runs great. it might need some optimization to take full advantage of the 6.5 liter, but my bet is the LIST that recommended the much larger injectors is at fault for a car that could be running better. if i did what i wanted, i would have the 24lb injectors, knowing that the stock S4 stuff on a 6.5 liter wouldnt be able to make over 400rwhp on a good day, and like john says, i would rather have 70psi pressures on a 85 injector , .like i had on the S4 injectors , than 44psi on an injector i could "grow" into when i had the cash to put on the CF Intake.
02-06-2012, 05:34 PM
#17
Rennlist Member
I seriously doubt you can mix and match fuel rail pressure and manifold vacuum together. The pressure regulators work by applying manifold vacuum to a spring loaded diaphragm, such that at idle (~ -10psi -0.7bar) the diaphragm is pulled off seat and reduces rail pressure (less fuel needed). My pressure readings on an LH (another make of car) showed idle pressure of 37-39psi with vacuum connected, 43-44psi no vacuum, a much lower change than the 10psi vacuum.
jp 83 Euro S AT 54k
jp 83 Euro S AT 54k
02-06-2012, 05:44 PM
#18
That you can hear. With no knock stethescope. Or anything like a sharktuner listening. Just you. Trying to hear the "pings" over the exhaust.
The useful comments have already been made. But as we all know, you will not listen to them.
Just wanted to save this one.
The useful comments have already been made. But as we all know, you will not listen to them.
Just wanted to save this one.
02-06-2012, 05:44 PM
#19
Rennlist Member
Thread Starter
Wow? ? ? Really ?
We are talking modern MPI systems? I have never seen a EFI MPI setup with less than 30PSI on the rail. 36~40 psi is what I'm used to seeing even on NA cars. Turbo cars usually have a boost referenced fuel pressure regulator, and its typically a 1:1 ratio. Why your fuel pressure is so low at Idle is amazing and not very typical. What will end up happening with that low pressure is your injector pulse will have to be very long, and that will cause problems at high rpms' . Using injectors sized for a 5.0 motor (And sized pretty small I may add) will cause problems on a 6.5 liter motor (pretty easy to see why.) Preferably you would want to have large enough injectors so you can run a sane Fuel line pressure and still have the headroom so that you are not maxing out your injectors at the top of your operating envelope.
I have tuned turbo car's for years and if you are running that much pressure on the rail its usually a sign the injectors are undersized..
Wow.. <SMH>
From all the information you posted sounds like you need someone with a WB 02 sensor, knowledge of Sharktuner, a good dyno and a few hours (Days) of tuning or you will be rebuilding something soon.. Many internet calculators for injector sizing and other things that are useful when putting together your baseline tune.
[skill and experience matters here, no time for beginners..]
We are talking modern MPI systems? I have never seen a EFI MPI setup with less than 30PSI on the rail. 36~40 psi is what I'm used to seeing even on NA cars. Turbo cars usually have a boost referenced fuel pressure regulator, and its typically a 1:1 ratio. Why your fuel pressure is so low at Idle is amazing and not very typical. What will end up happening with that low pressure is your injector pulse will have to be very long, and that will cause problems at high rpms' . Using injectors sized for a 5.0 motor (And sized pretty small I may add) will cause problems on a 6.5 liter motor (pretty easy to see why.) Preferably you would want to have large enough injectors so you can run a sane Fuel line pressure and still have the headroom so that you are not maxing out your injectors at the top of your operating envelope.
I have tuned turbo car's for years and if you are running that much pressure on the rail its usually a sign the injectors are undersized..
Wow.. <SMH>
From all the information you posted sounds like you need someone with a WB 02 sensor, knowledge of Sharktuner, a good dyno and a few hours (Days) of tuning or you will be rebuilding something soon.. Many internet calculators for injector sizing and other things that are useful when putting together your baseline tune.
[skill and experience matters here, no time for beginners..]
NOW< my friends car . AGAIN< ITS NOT MY CAR!!!!! im driving it around town, babing it, keeping it running every week just to keep it healthy. fixing little things as i have time. Im doing the EXPERINECED thing with making sure its in the healthy running range. its timed right, but no comfirmation with valve timign, and will get a porken tool to check that out. the pulleys are off , but thats not that unusual, espeicaly since the heads were shaved.
i think its fuel pressure related and the injectors are WAY TOO BIG. this car, at 320rwhp, same as my old Holbert motor, could easily use the stock S4 injectors, or optimally, the 85 injectors.
this is what i want to talk about.
sure, we could shark tune it too, which would be a great thing to do if bill is around and wants to do it. otherwise. my experience tells me, it needs to be tuned with normal pressure, at least near 44psi and see what the air fuel ratios are. again, its runnning closed looop so the o2 sensor and ECU is doing a good job of keeping the ratios safe for around town. WOT, i dont know yet. still need to pull some plugs, do compression test and hook up my AFR meter.
02-06-2012, 05:46 PM
#20
Rennlist Member
Thread Starter
I seriously doubt you can mix and match fuel rail pressure and manifold vacuum together. The pressure regulators work by applying manifold vacuum to a spring loaded diaphragm, such that at idle (~ -10psi -0.7bar) the diaphragm is pulled off seat and reduces rail pressure (less fuel needed). My pressure readings on an LH (another make of car) showed idle pressure of 37-39psi with vacuum connected, 43-44psi no vacuum, a much lower change than the 10psi vacuum.
jp 83 Euro S AT 54k
jp 83 Euro S AT 54k
02-06-2012, 05:52 PM
#21
Race Car
PEM modules don't cost so much, don't take long to install, and it is very easy to modify the tune very quickly once they are in. IMO every single modified '87+ 928 should have them, even if only to have the same program as they were running with stock chips. Then at any point in time someone can just hook up an ST2, wbO2 and start tuning, although IMO again every modified 928 should have a permanently installed wbO2 and gauge.
Dan
'91 928GT S/C 475hp/460lb.ft
Dan
'91 928GT S/C
475hp/460lb.ft
02-06-2012, 05:58 PM
#22
Rennlist Member
Thread Starter
now as far as listening. im not listening to those that dont read.
my buid up, i was listening to the entire list for months on the build. we took all the comments into consideration and then did what we could afford to do and did all the checks to make sure it was safe. (as well as consulting along the way with Tim and Todd ) So, settle down.
proof is in the car, right chuck. does my car handle, does it run well?? am I posting stories about engines blowing up??? maybe you should do some listening yourself.
02-06-2012, 07:25 PM
#23
K, Chuck
02-06-2012, 09:24 PM
#26
Rennlist Member
Thread Starter
clowns!
speedtoys still thinks his car street mazda, on street rubber, goes faster through T-hill turn 8 than a cup car.
the proof is in the performance. How many 928s racing under my care? how many blown engines?
how many times did the "experts" say something couldnt be done, that was????
I just laugh, do my research, building, testing, race and have fun. You guys can debate the obvious!
speedtoys still thinks his car street mazda, on street rubber, goes faster through T-hill turn 8 than a cup car.
the proof is in the performance. How many 928s racing under my care? how many blown engines?
how many times did the "experts" say something couldnt be done, that was????
I just laugh, do my research, building, testing, race and have fun. You guys can debate the obvious!
02-06-2012, 09:35 PM
#27
Rennlist Member
Thread Starter
so, "chuck" what do you suggest i do with "My car"?? any suggestions rather than childish insults?
did you know we have already taken steps to make sure it is running near perfect. Talk to billl ball how i have it running, or take a look at the Holbert engine block in pristine shape after 10 years of ***** out racing.
or the advice given to me by the short block builders and the list used in the builtd up. SURE, i could have spent more money and had more HP, but how many guys do YOU know that have raced a 928 as much as i have that have no engine issues what so ever. now you can tell me its my driving, or my luck or 15 other things , but in the end, proof is in my record of times and competiiveness, as well as data presented here.
I dont see you contributing anything more than cheap arrogant shots across the bow, just to what, help? is that what you are trying to do, help??
Please, if you are going to help, understand the story first! you didnt even know it wasnt my car!!
Also, you didnt know that we tried to get a shark tune on my car and were stumpted by the ECU connectivity. alll in all, with lots of dyno time, and Wideband O2 sensor readings, the car is running reasonably well. again, im sure with some cash i could get it to 400rwhp vs the 372rwhp its now at.
In the end. you can bank on all the "scientists" trying to reinvent the wheel, or on somome that spends less time on the race car than anyone at the track because it just plain works. SO, argue that!
did you know we have already taken steps to make sure it is running near perfect. Talk to billl ball how i have it running, or take a look at the Holbert engine block in pristine shape after 10 years of ***** out racing.
or the advice given to me by the short block builders and the list used in the builtd up. SURE, i could have spent more money and had more HP, but how many guys do YOU know that have raced a 928 as much as i have that have no engine issues what so ever. now you can tell me its my driving, or my luck or 15 other things , but in the end, proof is in my record of times and competiiveness, as well as data presented here.
I dont see you contributing anything more than cheap arrogant shots across the bow, just to what, help? is that what you are trying to do, help??
Please, if you are going to help, understand the story first! you didnt even know it wasnt my car!!
Also, you didnt know that we tried to get a shark tune on my car and were stumpted by the ECU connectivity. alll in all, with lots of dyno time, and Wideband O2 sensor readings, the car is running reasonably well. again, im sure with some cash i could get it to 400rwhp vs the 372rwhp its now at.
In the end. you can bank on all the "scientists" trying to reinvent the wheel, or on somome that spends less time on the race car than anyone at the track because it just plain works. SO, argue that!
02-06-2012, 09:36 PM
#28
Archive Gatekeeper
Rennlist Member
Rennlist Member
Then why are you asking for help? I thought I'd be a big help by sending you a WBO2, ST2 and PEMs but apparently that wasn't helpful? What would be helpful? If you'd like it all back for this street stroker, let me know and I'll mail it all back, but I'd like to get paid for the PEMs if they actually get put into a brain, this time.
I thought I'd be a big help by sending you a WBO2, ST2 and PEMs but apparently that wasn't helpful? What would be helpful? If you'd like it all back for this street stroker, let me know and I'll mail it all back, but I'd like to get paid for the PEMs if they actually get put into a brain, this time.
02-06-2012, 09:43 PM
#29
Rennlist Member
Thread Starter
Then why are you asking for help? I thought I'd be a big help by sending you a WBO2, ST2 and PEMs but apparently that wasn't helpful? What would be helpful? If you'd like it all back for this street stroker, let me know and I'll mail it all back, but I'd like to get paid for the PEMs if they actually get put into a brain, this time.
I thought I'd be a big help by sending you a WBO2, ST2 and PEMs but apparently that wasn't helpful? What would be helpful? If you'd like it all back for this street stroker, let me know and I'll mail it all back, but I'd like to get paid for the PEMs if they actually get put into a brain, this time.you know i wasnt talking to you!
I would love to fine tune my rig, but Bill and I got some time into mine and did what we could do.
now, this car is another story. I would love to help this guy out, especially since im driving it arond occasionally. you certainly have the right idea.
i dont want to crank up this fuel pressure blindly and then start washing down cylinders.
, but its hard to imagine how this car could run on 20psi.ill probably just do the AFR to see what its at, and then make an decision if i dont have access with the good stuff!
I agree , this thing needs some sophisticated help and im just trying to narrow down the problems , in a way that cant hurt anything.
so, back on topic.
02-06-2012, 09:47 PM
#30
Rennlist Member
Thread Starter
I bought a pair of PEMs and sent them, a WBO2 and my ST2 to Kibort (by way of Bill Ball) in May 2011 in hopes that he'd use them on the racer (I have $100 in that engine too). Bill kindly offered to help with the Sharktuning.
https://rennlist.com/forums/8551180-post242.html
Got 'em back in December, not sure that they ever made it into the car. You can lead a man to water, but you cannot make him drink.
https://rennlist.com/forums/8551180-post242.html
Got 'em back in December, not sure that they ever made it into the car. You can lead a man to water, but you cannot make him drink.
thanks so much for that, we did get some use out of most of the equip, but fell short of our goals.Mark
love to try it again with this car, which is a bone stock S4