Low end poor throttle response
01-25-2008, 04:41 AM
#16
Three Wheelin'
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Jeff,
they disconnect the O2 when making the adjustment, then reconnect it, which I believe is good practice, no?
Anyway, car back last night. It had been too rich. They have now set the idle down 1.3 CO. It idles correctly and accelerates off boost nicely (as well as on boost which was not a problem). They said the air meter they use checks the mixture further up and it is all fine.
The only niggle I have is, while stationary, if I stab the thottle from idle quickly and repeatedly then it will misfire. Still too rich? Maybe I have to accept this to ensure its rich enough higher up, on boost? Or should I ask them to lean it out further?
....or just don't stab the throttle from idle!!
they disconnect the O2 when making the adjustment, then reconnect it, which I believe is good practice, no?
Anyway, car back last night. It had been too rich. They have now set the idle down 1.3 CO. It idles correctly and accelerates off boost nicely (as well as on boost which was not a problem). They said the air meter they use checks the mixture further up and it is all fine.
The only niggle I have is, while stationary, if I stab the thottle from idle quickly and repeatedly then it will misfire. Still too rich? Maybe I have to accept this to ensure its rich enough higher up, on boost? Or should I ask them to lean it out further?
....or just don't stab the throttle from idle!!
01-25-2008, 05:40 AM
#17
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Jeff,
they disconnect the O2 when making the adjustment, then reconnect it, which I believe is good practice, no?
Anyway, car back last night. It had been too rich. They have now set the idle down 1.3 CO. It idles correctly and accelerates off boost nicely (as well as on boost which was not a problem). They said the air meter they use checks the mixture further up and it is all fine.
The only niggle I have is, while stationary, if I stab the thottle from idle quickly and repeatedly then it will misfire. Still too rich? Maybe I have to accept this to ensure its rich enough higher up, on boost? Or should I ask them to lean it out further?
....or just don't stab the throttle from idle!!
they disconnect the O2 when making the adjustment, then reconnect it, which I believe is good practice, no?
Anyway, car back last night. It had been too rich. They have now set the idle down 1.3 CO. It idles correctly and accelerates off boost nicely (as well as on boost which was not a problem). They said the air meter they use checks the mixture further up and it is all fine.
The only niggle I have is, while stationary, if I stab the thottle from idle quickly and repeatedly then it will misfire. Still too rich? Maybe I have to accept this to ensure its rich enough higher up, on boost? Or should I ask them to lean it out further?
....or just don't stab the throttle from idle!!
Steve
01-25-2008, 05:40 AM
#18
Rennlist Member
sounds like Craig & Peter have done a good job for you - would you recommend them to other turbo
owners ? Lets hope you are out in the clear at last !
owners ? Lets hope you are out in the clear at last !
01-25-2008, 08:19 AM
#19
Three Wheelin'
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Steve,
I have been to 7 specialist garages since owning these cars, and phoned several more. Not one of them takes full AFR readings, this is a symptom of the UK Porsche engineering fraternity. Even Bob Watson on his rolling rioad didn't. They go by CO readings here. And there are only a handful of dynos in the UK that can take our cars.
I have a 0.8 bar spring which will net 1 bar. This is as advised by IA and Ulitmate who make the HFS. Bob Watson confirmed that my readings are do not surpass 1 bar even when he installed a 1 bar spring before.
Jonny, yes I am impressed with GTOne and would recommend them for their work and helpful attitude. It is a little disppointing that the mixture isn't quite right, but maybe that is because they don't know my individual car yet.
I will drive the car over the next few weeks and take it back to the garage. If it isn't an air leak, I will ask them to lean it a little bit more, as before it was running 100% smooth at 0.5 idle.
I have been to 7 specialist garages since owning these cars, and phoned several more. Not one of them takes full AFR readings, this is a symptom of the UK Porsche engineering fraternity. Even Bob Watson on his rolling rioad didn't. They go by CO readings here. And there are only a handful of dynos in the UK that can take our cars.
I have a 0.8 bar spring which will net 1 bar. This is as advised by IA and Ulitmate who make the HFS. Bob Watson confirmed that my readings are do not surpass 1 bar even when he installed a 1 bar spring before.
Jonny, yes I am impressed with GTOne and would recommend them for their work and helpful attitude. It is a little disppointing that the mixture isn't quite right, but maybe that is because they don't know my individual car yet.
I will drive the car over the next few weeks and take it back to the garage. If it isn't an air leak, I will ask them to lean it a little bit more, as before it was running 100% smooth at 0.5 idle.
01-25-2008, 10:10 AM
#20
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Mark, as i've said in the past, GForce have a Dyno Dynamics cell which is perfect for aircooled motors as they have plenty of cooling, plus their charts give you everything, RWBHP, FWBHP, AFR or Lamda, Boost level, Torque all plotted across the rev range on an A4 graph.
They are only in Aylesbury too, you should take the car there one day when it's running right and just see where you are fuel wise, you don't want a hole in a piston like i had!
If you get the adjustable WUR fitted and get GTOne to set the control pressures to stock (like the WUR you have on the car now) then go to GForce and get it on the rollers, if it needs more fuel at WOT just make the adjustments to it yourself (or ask them to do it), following the manual, while it's on the rollers in between runs, that way you can make it plenty rich enough at the top and not worry about it! I'll even come with you if you like!
This is what the graphs look like, as you can see it gives you ALL the info you'll ever need, what more could you want? It doesn't matter whether the BHP and Torque figures are perfectly accurate, you can count on the boost and AFR figures and those are what really matter!!
Notice on the fuel chart at the top it reads in Lamda, it looks like it was heading towards around 0.84 at 6500rpm and would have probably been around 0.85 or more at the red line which was much too lean, here is a chart showing the relationship between Lamda and AFR.
I would have been nearly 13.0:1 when the absolute limit should be 12.2:1. If you are going to the next VMax and you're running lean mate you're going to be a very unhappy man.
They are only in Aylesbury too, you should take the car there one day when it's running right and just see where you are fuel wise, you don't want a hole in a piston like i had!
If you get the adjustable WUR fitted and get GTOne to set the control pressures to stock (like the WUR you have on the car now) then go to GForce and get it on the rollers, if it needs more fuel at WOT just make the adjustments to it yourself (or ask them to do it), following the manual, while it's on the rollers in between runs, that way you can make it plenty rich enough at the top and not worry about it! I'll even come with you if you like!
This is what the graphs look like, as you can see it gives you ALL the info you'll ever need, what more could you want? It doesn't matter whether the BHP and Torque figures are perfectly accurate, you can count on the boost and AFR figures and those are what really matter!!
Notice on the fuel chart at the top it reads in Lamda, it looks like it was heading towards around 0.84 at 6500rpm and would have probably been around 0.85 or more at the red line which was much too lean, here is a chart showing the relationship between Lamda and AFR.
I would have been nearly 13.0:1 when the absolute limit should be 12.2:1. If you are going to the next VMax and you're running lean mate you're going to be a very unhappy man.
01-25-2008, 11:57 AM
#21
Rennlist Member
maybe we could get some turbos together for a dyno day this spring at G Force and get a group discount ?!
01-25-2008, 12:06 PM
#22
Burning Brakes
01-25-2008, 12:27 PM
#23
Steve,
I have been to 7 specialist garages since owning these cars, and phoned several more. Not one of them takes full AFR readings, this is a symptom of the UK Porsche engineering fraternity. Even Bob Watson on his rolling rioad didn't. They go by CO readings here. And there are only a handful of dynos in the UK that can take our cars.
I have a 0.8 bar spring which will net 1 bar. This is as advised by IA and Ulitmate who make the HFS. Bob Watson confirmed that my readings are do not surpass 1 bar even when he installed a 1 bar spring before.
Jonny, yes I am impressed with GTOne and would recommend them for their work and helpful attitude. It is a little disppointing that the mixture isn't quite right, but maybe that is because they don't know my individual car yet.
I will drive the car over the next few weeks and take it back to the garage. If it isn't an air leak, I will ask them to lean it a little bit more, as before it was running 100% smooth at 0.5 idle.
I have been to 7 specialist garages since owning these cars, and phoned several more. Not one of them takes full AFR readings, this is a symptom of the UK Porsche engineering fraternity. Even Bob Watson on his rolling rioad didn't. They go by CO readings here. And there are only a handful of dynos in the UK that can take our cars.
I have a 0.8 bar spring which will net 1 bar. This is as advised by IA and Ulitmate who make the HFS. Bob Watson confirmed that my readings are do not surpass 1 bar even when he installed a 1 bar spring before.
Jonny, yes I am impressed with GTOne and would recommend them for their work and helpful attitude. It is a little disppointing that the mixture isn't quite right, but maybe that is because they don't know my individual car yet.
I will drive the car over the next few weeks and take it back to the garage. If it isn't an air leak, I will ask them to lean it a little bit more, as before it was running 100% smooth at 0.5 idle.
Jeff,
they disconnect the O2 when making the adjustment, then reconnect it, which I believe is good practice, no?
Anyway, car back last night. It had been too rich. They have now set the idle down 1.3 CO. It idles correctly and accelerates off boost nicely (as well as on boost which was not a problem). They said the air meter they use checks the mixture further up and it is all fine.
The only niggle I have is, while stationary, if I stab the thottle from idle quickly and repeatedly then it will misfire. Still too rich? Maybe I have to accept this to ensure its rich enough higher up, on boost? Or should I ask them to lean it out further?
....or just don't stab the throttle from idle!!
they disconnect the O2 when making the adjustment, then reconnect it, which I believe is good practice, no?
Anyway, car back last night. It had been too rich. They have now set the idle down 1.3 CO. It idles correctly and accelerates off boost nicely (as well as on boost which was not a problem). They said the air meter they use checks the mixture further up and it is all fine.
The only niggle I have is, while stationary, if I stab the thottle from idle quickly and repeatedly then it will misfire. Still too rich? Maybe I have to accept this to ensure its rich enough higher up, on boost? Or should I ask them to lean it out further?
....or just don't stab the throttle from idle!!
You have a lot going on here...
Regarding the fuel mixture, I've tried running with the O2 sensor unplugged but found the fuel economy and throttle response unacceptable.
If you are running 1 bar there's a good chance you are lean at the top. I tried the advice of running with the O2 unplugged and riching it up but this showed no measureable change on the dyno (ie...still lean). I adjusted the WUR for more fuel. This worked up top, however it added too much fuel in the mid range.
There seems to be enough differences car to car that you can't use one persons solution. As an example advice given regulary on the boards (here) simply did not work for my car. The best thing I did was 1) get on a dyno and 2) picked up a wide band.
01-25-2008, 12:45 PM
#24
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+1 with the lean up top i would think if you are running 1 bar boost,,i am sure the recomended co setting on idle is around 2.5% to run 1 bar boost especially for you with that bigger hfs turbo in there,,correct though with the unplugged to set the co,,i have left mine unplugged and see no issues
I know it is even more cash for you but to save ruining all that good money you have spent to get the car the way you like it,you would be better buying the zeitronix afr set that i and a few other have on here to data log your readings to see whats going on in there!!..
2-3 hours on a roll and road and its paid for itself and also its always in your car constantly monitoring!!
There was speak of a few other rennlisters here up for a group buy on the set up!.
I know it is even more cash for you but to save ruining all that good money you have spent to get the car the way you like it,you would be better buying the zeitronix afr set that i and a few other have on here to data log your readings to see whats going on in there!!..
2-3 hours on a roll and road and its paid for itself and also its always in your car constantly monitoring!!
There was speak of a few other rennlisters here up for a group buy on the set up!.
01-25-2008, 12:57 PM
#25
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I have a brand new (used for 250miles) Innovate LM1 sat in a box which i'm never going to have use for now, that is what Steven at IA uses to tune his cars on the dyno, it also records and logs etc. I never really got the chance to get properly to grips with it, but it's there if you want to have a go with it Mark, you need to have a bung welded in the exhaust to fit the sensor but you can borrow it for a while if you like and if you want it you can make me an offer for it.
Just make sure whoever is sat next to you reading it is told what to look for, not like my mate who said nothing until my engine blew up! "It was saying 12.something mate but i couldn't read it" was his answer! Ah well......Live and learn!
I'd love to do a dyno day with you guys, might need a bit of time to get the new engine in the car though!
Just make sure whoever is sat next to you reading it is told what to look for, not like my mate who said nothing until my engine blew up! "It was saying 12.something mate but i couldn't read it" was his answer! Ah well......Live and learn!
I'd love to do a dyno day with you guys, might need a bit of time to get the new engine in the car though!
01-25-2008, 01:08 PM
#26
I thought I would just mention this again....I set my CO well past 2.5% while on the dyno and did not see a measurable improvement on AFR's.
I ended up getting more fuel by tweaking my WUR. Be sure to note I didn't fix my problem. I just went with the lessor evil here....ie too much fuel in the mid range for enough fuel in the high. Also worth mentioning, the first time I adjusted the WUR I got way to much fuel. These systems can give the fuel, the trick is to dole it out when and where you need it. I picked up the adjustable MSD rpm switch (alla Brian Leask) and will go there next.
I would never expect a shop to do this...they would go broke trying to get it right. For me anyway. It's just too easy to set the CO to 3%, take your money and send you on your way. I've had my pocket book emptied a few times myself and will do my best to avoid this (hopefully).
I ended up getting more fuel by tweaking my WUR. Be sure to note I didn't fix my problem. I just went with the lessor evil here....ie too much fuel in the mid range for enough fuel in the high. Also worth mentioning, the first time I adjusted the WUR I got way to much fuel. These systems can give the fuel, the trick is to dole it out when and where you need it. I picked up the adjustable MSD rpm switch (alla Brian Leask) and will go there next.
I would never expect a shop to do this...they would go broke trying to get it right. For me anyway. It's just too easy to set the CO to 3%, take your money and send you on your way. I've had my pocket book emptied a few times myself and will do my best to avoid this (hopefully).
01-25-2008, 02:04 PM
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I too have made adjustments in my own wur so i dont have to set the "co" as high as 3%,,i have mine set around 14.5 afr at idle and it only becomes rich when my rpm solenoid switch is triggered then i am around 12.0 afr at max revs,i also am a little rich when the boost enrichment is triggered with the rpm switch but i should be able to flatten my afr curve out better to stay nearer the 12.0 mark all the way up once the enrichment is in there once i adjust my wur more some!!
Mark i believe has not fitted an adjustable wur at the present moment i believe??..that is why he is better i believe to have the co set around 3% to compensate when his boost comes in,,especially for near the red line in my opinion just to make sure until he can get his afr measured,,it is pretty rough way of tuning but with no afr getting measured its better too rich than too lean
3% will be too rich for idle/cruise probably but i believe you will need this for 1 bar boost at wot/red line until you make your wur adjustable
I have also heard some good reviews on jons(jbl930) innovate afr product and either way anybody going to tune these engines would be best to get something in there to monitor air/fuel boost etc to save major headaches,,data logging tells you so much whats going on in there!!,,Your pretty working blind without these pieces of kit!!
Mark i believe has not fitted an adjustable wur at the present moment i believe??..that is why he is better i believe to have the co set around 3% to compensate when his boost comes in,,especially for near the red line in my opinion just to make sure until he can get his afr measured,,it is pretty rough way of tuning but with no afr getting measured its better too rich than too lean
3% will be too rich for idle/cruise probably but i believe you will need this for 1 bar boost at wot/red line until you make your wur adjustable
I have also heard some good reviews on jons(jbl930) innovate afr product and either way anybody going to tune these engines would be best to get something in there to monitor air/fuel boost etc to save major headaches,,data logging tells you so much whats going on in there!!,,Your pretty working blind without these pieces of kit!!
Last edited by stu.p; 01-25-2008 at 02:26 PM.
01-25-2008, 04:36 PM
#28
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stu, I am sorry to be blunt, but your info is wrong.
Setting the CO rich at idle makes little/ no difference to the car on WOT. I have had this from many techs, and even the gurus Stephen at IA and Brian Leask!
I have already said (and Jeff has said this too) that setting it at 3 did not make a difference. My car has run equally well at 0.5 and 2.8 CO idle, and the readings further up were the same regardless.
Don't mean to be rude but I won't be getting involved in any replies to CO at idle suggestions. Sorry :-)
Setting the CO rich at idle makes little/ no difference to the car on WOT. I have had this from many techs, and even the gurus Stephen at IA and Brian Leask!
I have already said (and Jeff has said this too) that setting it at 3 did not make a difference. My car has run equally well at 0.5 and 2.8 CO idle, and the readings further up were the same regardless.
Don't mean to be rude but I won't be getting involved in any replies to CO at idle suggestions. Sorry :-)
01-25-2008, 07:51 PM
#29
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As i said before i think this is a very ROUGH way of tuning setting "co" at idle which i DONT do,, I personally have ONLY ever set my car up by measuring my AFR/data logging etc which is the only correct way!!
This was me only trying to HELP you with the info i have collected in this forum about running higher boost safely using the rough "co at idle setting" to save you from maybe running too lean!!!
I am not too familiar with only setting co at idle method for tuning and unless i have read wrong I have cut and paste my info at bottom of page,,this was from a good source(a tech you mentioned above) in a thread about "running 1 bar boost" that YOU were involved in,,a thread that you quoted in that you thought our so called engine management sorted everything out for running 1 bar boost and nothing else was required to do!...which you now may agree sorry to be blunt mate your info was wrong!!..lol..
Again was only trying to help and ensure you had enough fuel going in there until you checked it out the CORRECT way..me being not personally familiar, i will not be getting involved either with this setting co at idle stuff
Good luck!
QUOTE!
Yes, you should reset the CO with the 02 unhooked. Anytime you add boost or HP you should recheck your AFRs and up your CO. When you set the CO you raise the mixture across the board. If you raise it 3% then it is raised 3% throughout the range. Not just at idle. You are physically moving the plate and changing the amount of fuel in the system. This can not be done just at idle.
__________________
This was me only trying to HELP you with the info i have collected in this forum about running higher boost safely using the rough "co at idle setting" to save you from maybe running too lean!!!
I am not too familiar with only setting co at idle method for tuning and unless i have read wrong I have cut and paste my info at bottom of page,,this was from a good source(a tech you mentioned above) in a thread about "running 1 bar boost" that YOU were involved in,,a thread that you quoted in that you thought our so called engine management sorted everything out for running 1 bar boost and nothing else was required to do!...which you now may agree sorry to be blunt mate your info was wrong!!..lol..
Again was only trying to help and ensure you had enough fuel going in there until you checked it out the CORRECT way..me being not personally familiar, i will not be getting involved either with this setting co at idle stuff
Good luck!
QUOTE!
Yes, you should reset the CO with the 02 unhooked. Anytime you add boost or HP you should recheck your AFRs and up your CO. When you set the CO you raise the mixture across the board. If you raise it 3% then it is raised 3% throughout the range. Not just at idle. You are physically moving the plate and changing the amount of fuel in the system. This can not be done just at idle.
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Last edited by stu.p; 01-25-2008 at 08:11 PM.
