Decrease in Driveability
Discussion
Had a performance "upgrade" including exhaust (cat back), but am now getting lower performance at 800-2000 revs. if treated carefully i can achieve more MPG but end up changing down more than before, efectively negating the MPG increase and making driving a more tedious experience..... have contacted the "upgrader" who is happy to look at the set up (when I have time) but just wondered if any one else has had tuning issues or am i a "one off" case?
I had the sport pac done to my '04 CV8 a few months ago and I'd have to agree with Wolfracer about the lack of low end grunt. You only have to look at the PDF link on the Monkfish website to see why. http://www.wortec.co.uk/dynosheets/04sportpac.pdf
Compared to the standard tune, we've lost a load of torque below 2500rpm. However, it does pull like a train above that now.....
Compared to the standard tune, we've lost a load of torque below 2500rpm. However, it does pull like a train above that now.....
Before my catback and remap I NEVER used to have to use the throttle to initially pull away when driving normally, (would pull away on tickover then feed in throttle...it was just smoother that way) not even when reversing up my steep drive which it would easily pull all the way up on tickover from standstill. Now I have to just stroke the throttle a tad as I pull away, (as per every other car!) still grunts up the drive on tickover once moving and still more low end torque than anything else I've driven, not really a problem, or even a niggle, like I said just normal for most cars and well worth the (small,..almost insignificant) sacrifice for the noise, response and mid/top end power increase. Have to say tho', on mine personally, I havn't really noticed any real low end power loss as such other than that mentioned, certainly nowhere near 2000rpm or even above 1000rpm! so maybe some other problem with yours.
Edited by skyblue465 on Saturday 30th June 11:33
loads of things it could be. Including zero power loss, but lower idle and/or reduced idle airflow and throttle cracker settings. Though with any mods the engine characteristics change and fueling and timing ideally need to be redone for all load points.. a labourous process for the hundreds of cells required..
Just to throw some thoughts into the pan.
Just to throw some thoughts into the pan.
stevieturbo said:
Wolfracer said:
Had a performance "upgrade" including exhaust (cat back), but am now getting lower performance at 800-2000 revs.
What did the upgrade include, and could you elaborate on lower performance ?
it was the sport pac, and the lower performance seems to be at just over tickover, almost like a flat spot or fuel starvation (sometimes it seems like it is going to stall when setting off unless you give it some welly - Not ideal on our local road at 6am!)
100% for aftersales care though - the company has been in touch and wants to look at the problem asap. it is me holding things up due to work commitments. I'm sure it can easily be solved and i will report back when it has been looked at.
PepV8 said:
I had the sport pac done to my '04 CV8 a few months ago and I'd have to agree with Wolfracer about the lack of low end grunt. You only have to look at the PDF link on the Monkfish website to see why. http://www.wortec.co.uk/dynosheets/04sportpac.pdf
Compared to the standard tune, we've lost a load of torque below 2500rpm. However, it does pull like a train above that now.....
The graphs tell allCompared to the standard tune, we've lost a load of torque below 2500rpm. However, it does pull like a train above that now.....
Maybe I am being thick, but looking at the graphs both mention a ratio of 3.460, on the HP graph it shows 113 mph @ 5254 rpm, with the sportpack it only shows 109 mph @ 5362 rpm, over a 100 rpm more but 4 mph slower, how come the discrepancy, I thought it would be the other way round, more rpm higher speed in same ratio.
Calculated Speeds, and even displayed rpm are variables that can input by the dyno operator.
Quite often they do not use a direct rpm pickup for the dyno graphs, so dont get too worked up if the rpm's displayed do not match up with actual road speeds, even more so from dyno to dyno.
And Gelf. I would say that a dyno graph tells very little
A dyno graph will show a power readout, between x and y rpm, usually at full throttle.
How often do you actually drive like that ? I spend a lot more time at lower throttle openings, and quite low rpm's. Most dyno graphs will not show this, yet it is the most important area of tuning in terms of driveability, as the car will probably spend 80-90% of its time there.
This needs to be right, and its teh hardest area of tuning.
Tuning to make outright power by comparison, is a doddle.
Quite often they do not use a direct rpm pickup for the dyno graphs, so dont get too worked up if the rpm's displayed do not match up with actual road speeds, even more so from dyno to dyno.
And Gelf. I would say that a dyno graph tells very little
A dyno graph will show a power readout, between x and y rpm, usually at full throttle.
How often do you actually drive like that ? I spend a lot more time at lower throttle openings, and quite low rpm's. Most dyno graphs will not show this, yet it is the most important area of tuning in terms of driveability, as the car will probably spend 80-90% of its time there.
This needs to be right, and its teh hardest area of tuning.
Tuning to make outright power by comparison, is a doddle.
Edited by stevieturbo on Saturday 30th June 21:05
stevieturbo said:
And Gelf. I would say that a dyno graph tells very little
A dyno graph will show a power readout, between x and y rpm, usually at full throttle.
How often do you actually drive like that ? I spend a lot more time at lower throttle openings, and quite low rpm's.]
Yes me too, and thats where performance has been reported to have suffered; I just meant their seat of the pants dyno reflected what is shown in the graphsA dyno graph will show a power readout, between x and y rpm, usually at full throttle.
How often do you actually drive like that ? I spend a lot more time at lower throttle openings, and quite low rpm's.]
Gelf VXR said:
[quote=stevieturbo]
I just meant their seat of the pants dyno reflected what is shown in the graphs
I just meant their seat of the pants dyno reflected what is shown in the graphs
Very true, even my Mrs' Zaf has more umph in the top gears than a 375 ish bhp V8. Hopefully there is a tune which gives low down torque AND high rev power. I am not a tuning expert (which is why i trust my pound notes to those that know) so do not know if this is possible but will be interested to find out....?
stevieturbo said:
How often do you actually drive like that ? I spend a lot more time at lower throttle openings, and quite low rpm's. Most dyno graphs will not show this, yet it is the most important area of tuning in terms of driveability, as the car will probably spend 80-90% of its time there.
This needs to be right, and its teh hardest area of tuning.
Tuning to make outright power by comparison, is a doddle.
So true stevie, outright power tells only a fraction of the story.
Good hot/cold starts, idle and low speed driveability is what separates the men from the boys.
A good tune should be better than stock everywhere in the driving spectrum, especially in the lower rpm's than whats provided from the factory with these engines pcm's.
Wolfracer, let whoever did your tune have a look at it, then if you're still not happy, have a talk to (IMHO) the best tuner down here.
www.chipmaster.com.au/
For only a couple of hundred quid, one of his mail order tunes would probably answer your concerns.
Gelf VXR said:
I just meant their seat of the pants dyno reflected what is shown in the graphs
I see nothing in that dynograph that would be a problem.If you refer to the start of the graph... at what rpm did the run really start, how was the throttle opened, what loadings were applied to the run etc etc...
So the start of that graph is meaningless without lots more info, yet people get soooo hooked up on dyno numbers etc ( and bonnet open/bonnet closed
)When in reality, they dont mean that much. A number is all good and well. But what if a car with a smaller set of numbers annihilates you on the road, and drives better ??
Might get confusing.
stevieturbo said:
If you refer to the start of the graph... at what rpm did the run really start, how was the throttle opened, what loadings were applied to the run etc etc...
So the start of that graph is meaningless without lots more info, yet people get soooo hooked up on dyno numbers etc ( and bonnet open/bonnet closed )
Might get confusing.
ExactlySo the start of that graph is meaningless without lots more info, yet people get soooo hooked up on dyno numbers etc ( and bonnet open/bonnet closed
)Might get confusing.
As a consumer, I have to ask my self why do the graphs provided not show the results from 1K, ( I might think now there is a reason) like you said we all use the available torgue there, my Ro will cruise along in 6th quite happly at 1K.
I'm not slating any of the performance tuners or any of the products they sell, as a consumer I would rather hear the reports from other consumers of services and products. If you are selling a product, you wouldn't want to highlight any negative points. This is a forum where you can come to find this sort of information and make an informed choice on your purchase.
I'm not new to buying upgrades, I spent 6K on my previous car, the first engine remap had a flat spot, it wasn't untill the next upgrade that I was happy.
I certainly wouldn't let the fact that I lost a little a the bottom end for a substantial incresae at the top put me off getting an upgrade, I think its important to know thou.
That is all
V-Car said:
So true stevie, outright power tells only a fraction of the story.
Good hot/cold starts, idle and low speed driveability is what separates the men from the boys.
A good tune should be better than stock everywhere in the driving spectrum, especially in the lower rpm's than whats provided from the factory with these engines pcm's.
http://www.chipmaster.com.au/
For only a couple of hundred quid, one of his mail order tunes would probably answer your concerns.
We have a very limited choice of performance upgrade paths in the uk, there little oppotunity to tell the men from the boys.Good hot/cold starts, idle and low speed driveability is what separates the men from the boys.
A good tune should be better than stock everywhere in the driving spectrum, especially in the lower rpm's than whats provided from the factory with these engines pcm's.
http://www.chipmaster.com.au/
For only a couple of hundred quid, one of his mail order tunes would probably answer your concerns.
I certainly wouldn't want a mail order tune, all engines are different a react differently, its got to be a dyno for fine tuning
Edited by Gelf VXR on Sunday 1st July 05:12
Gelf VXR said:
We have a very limited choice of performance upgrade paths in the uk, there little oppotunity to tell the men from the boys.
I certainly wouldn't want a mail order tune, all engines are different a react differently, its got to be a dyno for fine tuning
Unfortunately for Wolfracer, this obviously hasnt worked for him in this situation.
As you have said, far more tuning is done on these vehicles down here than in the UK, and in the case of the tuner ive mentioned, has, i dare say, more experience with these vehicles that any tuners in your part of the world.
Ofcourse, tuning on a dyno is the preferred option, but a tuner who knows his stuff and has tuned literally thousands of these particular vehicles, will provide a better tune, even mailorder when unfortunately the car isnt available as is so often the case down here with such great distances, even to many customers in the Middle East and South Africa, given all the parameters of the particular engine, than a less experienced tuner with the best equipment available.
Im sure, whoever the original tuner was, he may be able to find the cause of Wolfracers driveability issues, but im just trying to point out that there are other options available.
My turn to add some comments......
1. As I tuned the car and have the data logs I am more than happy that the tune is correct for the car.
As tunes go it was spot on first time, most cars receive 2-3 revisions from the base tune this car needed no revisions,
2. The customer mentioned that the cars idle appeared different to before, when he collected the car, this change in idle is normal on a 05 CV8 "BUT"......what I belive was not fully realised is that the customer had experienced a problem with the car that was not there when the car was signed off.
Without seeing the car (which is being or has been arranged)my first port of call are the O2 sensors which if failing will cause low throttle driving problems and a poor idle, the fact the car is fine when pushing on also points to o2 sensor problems as the car does not use them with larger throttle openings.
I understand the "Who touched it last broke it" mentality but just blindly pointing at the tuning is not a valid route to solving a problem!
3. The dyno sheets above as said by some people with a good grasp of how a car works only provides a trace of a single test .....that of a wide open throttle run in 4th gear from low RPM to max RPM. This test simply shows the peak Torque and Horsepower and should not be used as a guide to how a car drives, as you generaly dont put your car in 4th at a 1000rpm and then snap open the throttle and ride the car to the rev limit!!!!
To shed a little more light on the low end of the graph when we first dynoed the standard 04 CV8 some three years ago, we did the run from 1450rpm approx. When we finished the tune we found that with the increase in power the car started to invoke some "torque management", if run from 1450rpm. So the car was run from 2000rpm which is why the graph shows a difference as the origional car had been excellarating for some 500rpm before the tuned car had started.
When we tune a car for a pac we log and tune over a 1000miles in all conditions to get the best set up, a set up which cannot be produced on a dyno in a few hours! Our prefered representation of this power is via a "3d Torque model" which shows Tq/Hp at every load cell BUT at the moment this 3D model only excists in our computers and we are working on a way to output this so others can read and understand!
1. As I tuned the car and have the data logs I am more than happy that the tune is correct for the car.
As tunes go it was spot on first time, most cars receive 2-3 revisions from the base tune this car needed no revisions,
2. The customer mentioned that the cars idle appeared different to before, when he collected the car, this change in idle is normal on a 05 CV8 "BUT"......what I belive was not fully realised is that the customer had experienced a problem with the car that was not there when the car was signed off.
Without seeing the car (which is being or has been arranged)my first port of call are the O2 sensors which if failing will cause low throttle driving problems and a poor idle, the fact the car is fine when pushing on also points to o2 sensor problems as the car does not use them with larger throttle openings.
I understand the "Who touched it last broke it" mentality but just blindly pointing at the tuning is not a valid route to solving a problem!
3. The dyno sheets above as said by some people with a good grasp of how a car works only provides a trace of a single test .....that of a wide open throttle run in 4th gear from low RPM to max RPM. This test simply shows the peak Torque and Horsepower and should not be used as a guide to how a car drives, as you generaly dont put your car in 4th at a 1000rpm and then snap open the throttle and ride the car to the rev limit!!!!
To shed a little more light on the low end of the graph when we first dynoed the standard 04 CV8 some three years ago, we did the run from 1450rpm approx. When we finished the tune we found that with the increase in power the car started to invoke some "torque management", if run from 1450rpm. So the car was run from 2000rpm which is why the graph shows a difference as the origional car had been excellarating for some 500rpm before the tuned car had started.
When we tune a car for a pac we log and tune over a 1000miles in all conditions to get the best set up, a set up which cannot be produced on a dyno in a few hours! Our prefered representation of this power is via a "3d Torque model" which shows Tq/Hp at every load cell BUT at the moment this 3D model only excists in our computers and we are working on a way to output this so others can read and understand!
I have the focus pac, very pleased with it, haven't noticed any low down power loss. Way way better than the LSVS3 now goes like a bat out of hell and I seem to be getting about 2mpg more - has gone from 15 to 17 now average 
Can Wortec provide a power graph for the focus pac? Like to compare it to the runs I had at Abbey and WRC
Can Wortec provide a power graph for the focus pac? Like to compare it to the runs I had at Abbey and WRC
Edited by anonymous-user on Sunday 1st July 20:40
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