Why don't manufacturers "Map" their engines
Discussion
ddom said:
The point of a remap isn’t just willy waving power figures. It’s drive ability, smoothing out and removing the dips that are engineered into cars to pass emission tests. Dyno racing is pointless but remapping a car, when you have someone who knows what they are doing brings decent gains. Everyone would have you believe that the engines explode when not running the factory map, it’s just not the case IME. I remember the weak point on some cars was always clutches, the manufacturer has to allow for Granny to hammer the clutch, and it remain functional until the warranty has expired.
Yes, the remap I had done on my v70 D5 mainly improves the drivability at lower rpm. It feels much smoother and has much better throttle response in first half of the rev range with less throttle travel needed. Before at part throttle at lower rpm it always had a quite gruff / mechanical typically diesel sound but now that has completely gone and sounds much smoother and nicer. Peak torque / power feels a bit higher but the main difference is the better pick up. It uses a bit more fuel in like for like driving / conditions but I'd say it's worth it for the increased drivability. Can anyone answer this for me please. I've got a mk5 Golf gti which was remapped by the previous owner when it had a decat. I've since added a sports cat and put the centre pipe silencer 'delete' back in. Obviously the car was mapped to having no restrictions but now I have placed a restriction in the exhaust, will this damage the engine or just make it a bit less powerful?
scoey1001 said:
Can anyone answer this for me please. I've got a mk5 Golf gti which was remapped by the previous owner when it had a decat. I've since added a sports cat and put the centre pipe silencer 'delete' back in. Obviously the car was mapped to having no restrictions but now I have placed a restriction in the exhaust, will this damage the engine or just make it a bit less powerful?
TBH the only definite answer that can be given online is "it depends".ECU's on modern stuff (which I'd include MK5) tend to be able to adapt, within reason. But obviously depends on the map itself. Do you know which map it has / who did it? If so, perhaps best to contact the mapper.
I'd probably risk it....but perhaps not drive flat out in higher gears for sustained periods...but easy for me to say as not my car!
scoey1001 said:
Can anyone answer this for me please. I've got a mk5 Golf gti which was remapped by the previous owner when it had a decat. I've since added a sports cat and put the centre pipe silencer 'delete' back in. Obviously the car was mapped to having no restrictions but now I have placed a restriction in the exhaust, will this damage the engine or just make it a bit less powerful?
You should be ok but it depends if its a generic or custom map.Stage 2 usually needs a sports cat or decat, a silencer delete won't effect the remap, it will just make more noise.
If its a generic stage 2 remap and you have gone from decat to sports cat then its fine.
It's probably also worth pointing out that all mappers, and all maps aren't equal.
At one end you'll have knowledgeable tuners, who've sunk huge amounts of R&D into test vehicles, have their own rolling road facilities, and who will create a map specific to your car.
At the other end you'll have someone who's got hold of a cheap laptop and downloaded some maps from tinterweb, who can probably upload the map but won't be able to tell you anything about what it's doing and why.
And everything in between.
On a previous car, I'd changed the fuel pressure regulator, and the mapper had also found a temp sensor issue, where the ECU even when the sensor was swapped, consistently recorded lower temps than othe vehicles of the same make / model (which could of affected fuelling). They simply mapped to suit, with a number of rolling Road runs and normal road runs with a wide band lambda strapped to the back of he car to check AFR and tweak as needed.
At one end you'll have knowledgeable tuners, who've sunk huge amounts of R&D into test vehicles, have their own rolling road facilities, and who will create a map specific to your car.
At the other end you'll have someone who's got hold of a cheap laptop and downloaded some maps from tinterweb, who can probably upload the map but won't be able to tell you anything about what it's doing and why.
And everything in between.
On a previous car, I'd changed the fuel pressure regulator, and the mapper had also found a temp sensor issue, where the ECU even when the sensor was swapped, consistently recorded lower temps than othe vehicles of the same make / model (which could of affected fuelling). They simply mapped to suit, with a number of rolling Road runs and normal road runs with a wide band lambda strapped to the back of he car to check AFR and tweak as needed.
TonyTony said:
scoey1001 said:
Can anyone answer this for me please. I've got a mk5 Golf gti which was remapped by the previous owner when it had a decat. I've since added a sports cat and put the centre pipe silencer 'delete' back in. Obviously the car was mapped to having no restrictions but now I have placed a restriction in the exhaust, will this damage the engine or just make it a bit less powerful?
You should be ok but it depends if its a generic or custom map.Stage 2 usually needs a sports cat or decat, a silencer delete won't effect the remap, it will just make more noise.
If its a generic stage 2 remap and you have gone from decat to sports cat then its fine.
scoey1001 said:
Hi, it's a custom map which produces 262 bhp, so a bit more than a 'stage one' for the mk5 which usually gets around 240-250. But guessing the extra bhp was due to the intake/decat. Obviously now I've added a sports cat the bhp will be less but just concerned it might damage the engine. I spoke to the mapping company and they said it will need tweaking to suit the sports cat at a cost of £250 which seems steep as the original map was £350. But they wouldn't say exactly why/what might happen if I don't, just that I'd placed a restriction where the car has been mapped not to have one.
It will probably be ok as long as you don't go on a track day or similar but for piece of mind its probably worth having it looked at.R-Tech always seems to get recommended as the go to place for remaps on VAG cars
Lester H said:
It was said that the early BMW MINI could be re- mapped to a Cooper for next to nothing.(Obviously, not an S though. ) Was this so?
Yes. It uses an electronic throttle so, to save costs, the ECU in the One only opens the throttle to ~80% whereas the Cooper gives you the full 100%. I believe it’s the same with the V10 R8 vs Gallardo/HuracanSi1295 said:
Yes. It uses an electronic throttle so, to save costs, the ECU in the One only opens the throttle to ~80% whereas the Cooper gives you the full 100%. I believe it’s the same with the V10 R8 vs Gallardo/Huracan
Thanks. Never knew if this was an urban myth, or pub bore talk. Interesting.Edited by Lester H on Wednesday 24th February 19:13
The_Burg said:
The classic 'hobbled' car has to be the MINI, 1.6 and Cooper identical engines but the throttle doesn't open full on the cooking 1.6. Seem to have a recollection of Clarkson advising people not to buy the Cooper as it could be fixed for a couple of hundred?
90 and 115 BHP, all in the program. Get it re-calibrated and both have 125 BHP.
Years ago, I was told by a guy at Land Rover that the V8 rover engine had 295 OE variants in current production (1993)
They thought the cost of managing the variation could be saved by using the ECU settings, in alot of cases..
Lester H said:
Si1295 said:
Yes. It uses an electronic throttle so, to save costs, the ECU in the One only opens the throttle to ~80% whereas the Cooper gives you the full 100%. I believe it’s the same with the V10 R8 vs Gallardo/Huracan
Thanks from O.P. Never knew if this was an urban myth, or pub bore talk. Interesting.My mother had a rover 25 1.4ltr which was rated at 85bhp. It was the same as the 100bhp version, but with a throttle restriction.
98elise said:
Lester H said:
Si1295 said:
My mother had a rover 25 1.4ltr which was rated at 85bhp. It was the same as the 100bhp version, but with a throttle restriction.
It was a different shaped "cam" on the throttle spindle so full pedal opening by the driver only opened the throttle about 75% of the way! This is a decent way to limit power, as it still provides maximume engine torque at lower speeds, but limits airflow, so limits power only(i should know, i did the EU4 Rover K series calibration and emissions cert!)
Max_Torque said:
It was a different shaped "cam" on the throttle spindle so full pedal opening by the driver only opened the throttle about 75% of the way! This is a decent way to limit power, as it still provides maximume engine torque at lower speeds, but limits airflow, so limits power only
(i should know, i did the EU4 Rover K series calibration and emissions cert!)
That level of deliberate hobbling really does feel like offering a more expensive model of Rover 25 which is upgraded by dint of not having had a massive turd plumbed into the HVAC system.(i should know, i did the EU4 Rover K series calibration and emissions cert!)
Evo Sean said:
You won't see aftermarket tuners taking their car to altitude to check that it starts at 6000ft at -7degC.
Actually a very good comment! I live at the bottom of several 8000ft mountain passes, and yeah, no one considers that! The average buyer doesnt necessarily know or care about the difference in temperature, pressure or oxygen content at that altitude. Their expectation is that things just work - so contingency needs to be built in. Your average owner of a remapped car is going to be more aware and understand a little more - so understand that the contingency has been removed.
And dont forget super cold and super hot weather too! The same car has to be sold to places that need to cope with -25C in winter and 40C in summer! Got to have some contingency left in there to cope with that.
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