Performance Diesels ????
12 June 2014 | 12:04 PM
#182
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From: Api 500+bhp MD321T @91dB Probably SN's longest owner of an Impreza Turbo
I have a Q7 4.2tdi, I believe its a 335bhp version. I have seen these can be remapped to 400bhp with loads more torque.
I dont want to start removing cats and dpf filters, but what real performance gains will this upgrade do, eg 30-80mph acceleration and mpg improvements over standard car?
Who has mapped on of these cars here?
I dont want to start removing cats and dpf filters, but what real performance gains will this upgrade do, eg 30-80mph acceleration and mpg improvements over standard car?
Who has mapped on of these cars here?
12 June 2014 | 11:54 PM
#185
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From: Blackpool, Uk. Destination: Rev Limiter.
I have a Q7 4.2tdi, I believe its a 335bhp version. I have seen these can be remapped to 400bhp with loads more torque. I dont want to start removing cats and dpf filters, but what real performance gains will this upgrade do, eg 30-80mph acceleration and mpg improvements over standard car? Who has mapped on of these cars here?
Last edited by Evolution Stu; 12 June 2014 at 11:55 PM.
13 June 2014 | 12:10 AM
#186
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From: I'll check my gps
Hi Stu, not relevant to the thread but was just wondering where your based. Your profile says Blackpool (good for me 
) but then you keep mentioning about going to the track/ring.
And we've talked diesel but what about petrol?
) but then you keep mentioning about going to the track/ring. And we've talked diesel but what about petrol?
13 June 2014 | 12:12 AM
#187
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From: Blackpool, Uk. Destination: Rev Limiter.
03 July 2014 | 05:27 PM
#188
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From: Blackpool, Uk. Destination: Rev Limiter.
Acceleration times from standstill. (best recorded)
0 - 60mph = 4.82seconds
0 - 100mph = 11.37mph
In gear acceleration: (best recorded)
30 - 50mph = 1.75 seconds
50 -70mph = 2.29 seconds
70 - 100mph = 4.88 seconds[FONT="]
All times recorded with the Racelogic VBox Sport datalogger. Graphs look like this which show how well these change gear too.
Cant help you with the sub 4.5sec though. Maybe with an LSD and a set of normal tyres (IE: not poxy runflats), but as she is, theres too much power to get off the line without significant levels of wheelspin for a crap driver like me.
03 July 2014 | 10:36 PM
#191
Indeed the emission control systems can be a pain if not looked after, and sometimes even that doesn't help. The systems, whilst under complex PID control, are actually quite simple. EGR, which is used to change the temperature of combustion can still be bypassed with no problem (when done properly, not just switched off in ecu) and so can DPF (used to remove exhaust soot) currently as the only MOT check is a "visual" so if dealt with carefully, it can be removed and we have done literally thousands through our network, if not into the tens of thousands. However, a little common sense will actually stop these systems failing. The DPF is of course the big one... It can be a headache, but 80% of problems are operator error. (But not usually operator fault, as the operator is not up to speed with what the vehicle needs) Indeed a DPF can easily last over 100'000 miles.
A brief rundown...
A DPF requires a regeneration event when back-pressure starts to get high. Because this superheated the exhaust system, there are safeguards built into the program to ensure this is done with plenty of cooling airflow around it and on a engine in good enough health to take it. The programming looks like this...
If all the above conditions are met, it will initiate a DPF regeneration where injection events are added, and retarded, in order to superheat the exhaust system and catalyse the soot held within it. This process will continue until the back pressure sensor reports acceptable levels at which point the process ends and a timer is set to countdown to the next regeneration event.
Now, as any garage will tell you, the amount of vehicles that come into the workshop with ZERO management errors are very very few and far between. This means no regeneration will take place on said vehicles.
The most common one is glow plug errors, people assume because it starts ok they will ignore it, and ignorant garage staff back up this decision because they don't understand the complications this causes.
The next most common are thermostats leaking. It's VERY common on the BMW x30 and x35 motors. It only leaks off its seat slightly, but enough to drop coolant temps to around 86c. Again, ignorant garages, including main dealers, report this temperature as fine. It's not. Modern diesels almost exclusively run between 94 and 104 degrees and again, this small discrepancy stops regeneration events.
Another big one is oils... Did you know a DPF equipped car MUST run a special engine oil? Again, many bloody garages dont know (or care?) about this and continue to use the barrels they have in stock that give the most profit. Wrong oil clogs DPF's fast as they cant handle the soot that non DPF compatible oils cause!
Anyway, I'm waffling and I've a car to Dyno, but if anyone's interested to learn more, please just say so as I'm always happy to talk technical about cars, but fear it's boring you lot to tears so I will leave it right there for now.
A brief rundown...
A DPF requires a regeneration event when back-pressure starts to get high. Because this superheated the exhaust system, there are safeguards built into the program to ensure this is done with plenty of cooling airflow around it and on a engine in good enough health to take it. The programming looks like this...
- Engine temps must be higher than 90c
- Engine must have been running for over 30 mins
- No faults must be present in the management system
- The vehicle must be doing a steady state of OVER 40mph
- The vehicle must have been in this state for a few minutes
If all the above conditions are met, it will initiate a DPF regeneration where injection events are added, and retarded, in order to superheat the exhaust system and catalyse the soot held within it. This process will continue until the back pressure sensor reports acceptable levels at which point the process ends and a timer is set to countdown to the next regeneration event.
Now, as any garage will tell you, the amount of vehicles that come into the workshop with ZERO management errors are very very few and far between. This means no regeneration will take place on said vehicles.
The most common one is glow plug errors, people assume because it starts ok they will ignore it, and ignorant garage staff back up this decision because they don't understand the complications this causes.
The next most common are thermostats leaking. It's VERY common on the BMW x30 and x35 motors. It only leaks off its seat slightly, but enough to drop coolant temps to around 86c. Again, ignorant garages, including main dealers, report this temperature as fine. It's not. Modern diesels almost exclusively run between 94 and 104 degrees and again, this small discrepancy stops regeneration events.
Another big one is oils... Did you know a DPF equipped car MUST run a special engine oil? Again, many bloody garages dont know (or care?) about this and continue to use the barrels they have in stock that give the most profit. Wrong oil clogs DPF's fast as they cant handle the soot that non DPF compatible oils cause!
Anyway, I'm waffling and I've a car to Dyno, but if anyone's interested to learn more, please just say so as I'm always happy to talk technical about cars, but fear it's boring you lot to tears so I will leave it right there for now.
I test drove a 1.6 Petrol that looks exactly what i want , but its dead as a dodo. Now i realise i say i dont need performance , but the 1.6 was pathetic. I have found other Leons with the BTCC kit with a better spec , but they are all diesels. With me doing low mile short runs am i running into a world of problems ? Is the only way to "clear" the DPF filter by going on a 30+minute 40mph drive ? I wouldnt mind going for a spirited drive once a week , but 30 mins at 40mph would be a stretch for me.
03 July 2014 | 11:04 PM
#192
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From: I'll check my gps
i am currently looking at replacing my impreza with a Seat Leon (with a BTCC kit) . I dont need fuel economy , i dont need performance , dont need to modify/tune the engine and i do low miles and short runs.
I test drove a 1.6 Petrol that looks exactly what i want , but its dead as a dodo. Now i realise i say i dont need performance , but the 1.6 was pathetic. I have found other Leons with the BTCC kit with a better spec , but they are all diesels. With me doing low mile short runs am i running into a world of problems ? Is the only way to "clear" the DPF filter by going on a 30+minute 40mph drive ? I wouldnt mind going for a spirited drive once a week , but 30 mins at 40mph would be a stretch for me.
I test drove a 1.6 Petrol that looks exactly what i want , but its dead as a dodo. Now i realise i say i dont need performance , but the 1.6 was pathetic. I have found other Leons with the BTCC kit with a better spec , but they are all diesels. With me doing low mile short runs am i running into a world of problems ? Is the only way to "clear" the DPF filter by going on a 30+minute 40mph drive ? I wouldnt mind going for a spirited drive once a week , but 30 mins at 40mph would be a stretch for me.
04 July 2014 | 07:56 PM
#194
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From: Blackpool, Uk. Destination: Rev Limiter.
Not sure on weight but it's fully loaded with every option (bar HUD) and full leather, it even has the logic 7 amps and multiple subwoofer upgrade options so assume it's a lot heavier than the average 3 series.
04 July 2014 | 08:22 PM
#195
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DPF problems are somewhat exaggerated for sure. Certainly they exist. Yes of course they do but problems are normally caused by folk who simply do t understand what they do, how they do it and what's required to allow the regeneration.
Most regeneration is done passively.
Soot burn off occurs naturally at about 350c. To get the exhaust to this temperature requires a journey of around 30 mins as a rule, largely because of the pretty slow warm up of Diesel engines and how long it takes to heat sink everything and keep it all hot.
Generally speaking, a decent journey once a week will do the job no bother. The procedure you quoted was the requirement for the ecu to instigate an ACTIVE regeneration, which is an ecu intervention procedure when high back pressure is recorded and that brings the exhaust up to 650C, hence the requirement for speeds etc to keep it cool.
Remember it was 30 mins at OVER 40mph. 80mph on the motorway for example is fine.
That minimum requirement exists to ensure adequate airflow around very hot components.
04 July 2014 | 10:49 PM
#199
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From: england
personaly if i was concidering a derv it would be a non performance one.
they dont rev, they sound like vans, they chuck out black soot, they take ages to warm up if you run out of diesel you cant just throw some in and turn the key like a petrol car..
they dont rev, they sound like vans, they chuck out black soot, they take ages to warm up if you run out of diesel you cant just throw some in and turn the key like a petrol car..
05 July 2014 | 09:05 PM
#202
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5000rpm / sound nothing like vans / don't emit ANY smoke at all.
And as for running out of fuel, if you can't get to a pump within the 100miles warning the fuel light gives you then I'd guess you perhaps shouldn't be on the road anyway. Lol
Last edited by Evolution Stu; 05 July 2014 at 10:22 PM.
05 July 2014 | 09:34 PM
#203
Thats reasuring as allough the 1.6 petrol is still for sale , the cupra I was toying with buying has sold. So it'll be the 1.6 or a diesel if my car sells anytime soon. Spoke to 4 different diesel drivers in work that all do low miles and they all said theirs are fine. One of them (the only one that knows anything about cars) says in his VW Golf book to do 30 mins at 2k or more revs so I'd assume a 15 min drive on a carriageway would meet the criteria in a way.
08 July 2014 | 04:07 PM
#204
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Just try to remember its more about "time" than mileage.
The "time" aspect is the time required to saturate the exhaust and particulate filter with heat.
Technically, (and I practice this while repairing thus afflicted cars) i find the best way to do this is to drive the car hard, with as many revs and as much load as possible prior to dropping on the motorway and then just sit at about 65mph and hope for the best for the next 20 mins.
If the exhaust temps hold around 350 deg C then passive regeneration will be strongly in force and it will just clean itself naturally. How long this takes will depend entirely on how many grams of soot are present.
If an active intervention has been flagged in the ECU then your system should be in good enough condition and hot enough to get this running within a few minutes but again, the weight of soot in the system will determine the amount of time this takes.
For those who you who like to have dealer level diagnostics in their car (I always have) you will be able to bring up things like:
- EGT
- Regeneration requested
- Regeneration Active / not active
- Regenerations interupted
- Soot level in particulate filter (Weight in grams usually)
- Passive soot regeneration. (Weight in grams usually)
08 July 2014 | 06:48 PM
#205
Cheers for the info. Actually , a car came up for sale , colour I like , shape I like , and near to where I live , with the filter removed !
Only problem is I still a a subaru in the garage that no-one will buy !
Only problem is I still a a subaru in the garage that no-one will buy !
19 July 2014 | 08:03 AM
#206
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No problem at all, your very welcome.
Incidentlally, just reading some of this back and it's occurred to me there is a key element I have forgotten to mention.
A lot of systems measure oil quality and will not regenerate if the oil quality is low, so also make sure that your oil is changed regularly and, importantly, the oil service monitor in the ecu is reset. We get quite a few through the door that have been serviced and not had the service intervals reset so the ecu thinks the oil is very old and as a result it won't regen.
Incidentlally, just reading some of this back and it's occurred to me there is a key element I have forgotten to mention.
A lot of systems measure oil quality and will not regenerate if the oil quality is low, so also make sure that your oil is changed regularly and, importantly, the oil service monitor in the ecu is reset. We get quite a few through the door that have been serviced and not had the service intervals reset so the ecu thinks the oil is very old and as a result it won't regen.
03 August 2014 | 11:03 AM
#210
I had a MK1 Leon FR+ tdi. Had it revo mapped to 190bhp, was excellent car and looked great! So far i've had 3 leons 2 fr+ and one standard fr. 55+mpg's too! Only gripe was the seats were uncomfortable on long journeys
The Mk2's look nice, good solid engines
The Mk2's look nice, good solid engines