Discussion
trackcar said:
haynes do a book by dave walker of emerald, should be right up your street.
I would recommend that too - as well as websites : (in no particular order..)
http://www.emeraldm3d.com/em_projects_VVC.html#
http://www.megasquirt.info/index.html
http://www.vems.hu/wiki/index.php?page=GenBoard%2F...
http://www.m-techautomotive.co.uk/ecu/motec_glossa...
Whatever system you use if you plan to map yourself, i.e. alone in the car having wideband logging on the ECU is a godsend.
This will enable you to start the logging, go for a drive, stop, watch the recorded map trace along with the AFR, make changes as necesary then repeat the process.
Without wideband logging it makes things much harder and makes mapping a 2 person job really.
This will enable you to start the logging, go for a drive, stop, watch the recorded map trace along with the AFR, make changes as necesary then repeat the process.
Without wideband logging it makes things much harder and makes mapping a 2 person job really.
ringram said:
Try Amazon.
There are quite a few Jeff Hartman rings a bell. Try and get one with good reviews of course
As mentioned widebands are almost mandatory.. eventually you will see that dyno time is pretty much mandatory too, or else how do you measure timing gains/losses?
Eventually you will see that dyno measurements pretty irrelevant except for bragging rights. It's real-world performance that matters at the end of the day, and dynos don't tell you that.There are quite a few Jeff Hartman rings a bell. Try and get one with good reviews of course
As mentioned widebands are almost mandatory.. eventually you will see that dyno time is pretty much mandatory too, or else how do you measure timing gains/losses?
Green, a dyno is used for more than collecting dickpull figures to brag about down the pub.
Its a tool to be used to compare power/torque outputs before and after tuning.
Granted, the only way to measure true output is to put the engine on an engine dyno, but if I turn up at a chassis dyno with the car making 150hp and 130 lb/ft, then do some mapping and get 160hp and 140 lb/ft, I know I'm making more power post tuning, regardless of the accuracy of the figures.
You can get a fuel map pretty good on the road but as ringram says you really need a dyno to make the final adjustments to the ignition map especially as you can then see the changes in output and compare with EGT as you increase/decrease advance, then decide on a good comprimise between safety and power.
Its a tool to be used to compare power/torque outputs before and after tuning.
Granted, the only way to measure true output is to put the engine on an engine dyno, but if I turn up at a chassis dyno with the car making 150hp and 130 lb/ft, then do some mapping and get 160hp and 140 lb/ft, I know I'm making more power post tuning, regardless of the accuracy of the figures.
You can get a fuel map pretty good on the road but as ringram says you really need a dyno to make the final adjustments to the ignition map especially as you can then see the changes in output and compare with EGT as you increase/decrease advance, then decide on a good comprimise between safety and power.
You can do all that on a physical road just as well, and real-world in gear acceleration curves are far more meaningful than the power/torque curves that you will get on a chassis dyno OR an engine dyno. The only advantage of the dyno that I can see is that it allows you to hold the engine in a steady state long enough to optimise it interactively. The steady state that it holds it in isn't particularly representative of the conditions it will be working in in the real world though. If real world performance is the ultimate goal, then that is what you should be measuring.
GreenV8S said:
You can do all that on a physical road just as well, and real-world in gear acceleration curves are far more meaningful than the power/torque curves that you will get on a chassis dyno OR an engine dyno.
How do you propose to accurately measure an acceleration curve on the road? Your surely not suggesting something like a Gtech would be more accurate than a chassis dyno?
As you say tho being able to hold the engine at a particular cell on the map is another advantage of a dyno, sometimes its just not practical/easy/safe to do so on the road.
All I'm saying is its much easier and safer to map on a dyno, your not making repeated full throttle runs on a public road nor having to make allowances for traffic.
Edited by Marf on Sunday 19th August 15:31
Marf said:
How do you propose to accurately measure an acceleration curve on the road?
Most of the aftermarket ECUs will enable you to record RPM against time which gives you everything you really need to determine actual performance, they'll also record all the other sensor inputs so you can get a pretty good picture of what the engine was doing at the time. If you don't have this option then any decent data logger will let you log speed and revs against time and include various other parameters. For example my old DL90 will plot speed and position based on accelerometer input with GPS to compensate for drift, it'll log engine speed etc too. The only G-Tech I've used was one of those stick-on-the-windscreen jobs which was just a toy to be honest, but I'm sure they've improved over the years and perhaps they have stepped up into proper accurate data logging now.Don't agree green, have you ever mapped on a dyno? I have done both frequently recently. The dyno is significantly quicker and more accurate, and more importantly repeatable. 'real world' as you put it has its place, but once you exceed 400+ bhp (in a normal sized car) it gets pretty damn dodgy to map that kind of power on the road, and in every sense a dyno is a much better choice.
Fusion-Ed said:
'real world' as you put it has its place, but once you exceed 400+ bhp (in a normal sized car) it gets pretty damn dodgy to map that kind of power on the road, and in every sense a dyno is a much better choice.
I don't agree with your basic premise that tuning has to be done on a dyno.Real world performance is what is actually useful. If you have so much power that you can't sensibly use it on public roads for long enough to establish a map, then you need to find a different environment, perhaps on a dyno but not necessarily. In any case, I don't think we have established that the OP has this problem. Nothing at all wrong with using a dyno, and I would certainly agree that it's a quicker/easier/more reliable way to do it, but I don't agree that it is the only way to do it properly or the only way to get meaningful before/after comparisons.
I helped my mate map his megasquirted grif 500. Mapping the high RPM points at several leptons was getting silly to say the least. It would be much nicer to sit in a dyno cell adjusting things.
Having said all of that, he put it on the dyno at the grif growl on saturday and pulled 299bhp - which was only bettered by a 5.4L special- so we were both very happy with our DIY efforts - goes to show you dont needs lots of billet and bling to pull good numbers.
Having said all of that, he put it on the dyno at the grif growl on saturday and pulled 299bhp - which was only bettered by a 5.4L special- so we were both very happy with our DIY efforts - goes to show you dont needs lots of billet and bling to pull good numbers.
GreenV8S I can tell you dont map engines.
Tell me how on the road you optimise timing at 0.40g/cyl and 4000rpm?
Clearly its impossible to hold the load at that point for more than a split second.
An engine or chassis dyno that will hold a load is perfect for engine mapping.
If an engine is optimal under all load points on a dyno then why wont it be optimal under all load points on the road?
What factors are different? All wind resistance does is increase the loading...!
Tell me how on the road you optimise timing at 0.40g/cyl and 4000rpm?
Clearly its impossible to hold the load at that point for more than a split second.
An engine or chassis dyno that will hold a load is perfect for engine mapping.
If an engine is optimal under all load points on a dyno then why wont it be optimal under all load points on the road?
What factors are different? All wind resistance does is increase the loading...!
I think Pete was just pointing out that Dyno mapping is not perfect.
Sure - mapping a 400 / 500 bhp beast on the road is nuts..
Things that make dyno mapping less that idea must be :
Air load
only mapped in one gear .. surely the others will then read different.
Mapping Ignition - it's the way to go
But for fuel - the diagnostic software would well show that over a period of time (gears and load) that a slightly different setting may actually be better
but for easy of use the RR - it's unbeatable
Sure - mapping a 400 / 500 bhp beast on the road is nuts..
Things that make dyno mapping less that idea must be :
Air load
only mapped in one gear .. surely the others will then read different.
Mapping Ignition - it's the way to go
But for fuel - the diagnostic software would well show that over a period of time (gears and load) that a slightly different setting may actually be better
but for easy of use the RR - it's unbeatable
rev-erend said:
I think Pete was just pointing out that Dyno mapping is not perfect.
Sure - mapping a 400 / 500 bhp beast on the road is nuts..
Things that make dyno mapping less that idea must be :
Air load
only mapped in one gear .. surely the others will then read different.
Mapping Ignition - it's the way to go
But for fuel - the diagnostic software would well show that over a period of time (gears and load) that a slightly different setting may actually be better
but for easy of use the RR - it's unbeatable
If you map all load points when you are in a different gear at the same speed load will be different yes... but you have already mapped that load cell.Sure - mapping a 400 / 500 bhp beast on the road is nuts..
Things that make dyno mapping less that idea must be :
Air load
only mapped in one gear .. surely the others will then read different.
Mapping Ignition - it's the way to go
But for fuel - the diagnostic software would well show that over a period of time (gears and load) that a slightly different setting may actually be better
but for easy of use the RR - it's unbeatable
For economy of course a different fuel ratio is more ideal and on the road trial and error helps. But if you are talking power, then hands down the current best way is on a dyno. Anyone who thinks they can tune all load points on the road is sadly mistaken.
I'm not saying that mapping on a road is better than mapping on a dyno. I don't know of any professional tuner who maps cars on the road in preference to a dyno. For ease of use, speed, consistency and so it's a no-brainer.
What I disagree with is your assertion that you *have* to use a dyno to do the job properly, or that you have to use a dyno to obtain before/after measurements.
If you're able to take the engine through the full rev range at full throttle then you can map it on the road, it just takes much longer. That isn't going to be practical in some cases but in cases where it is practical there's nothing wrong with it if you don't mind taking a long time.
Mapping it on the road might even give you a more accurate map under some circumstances. Dynos aren't completely representative of how the engine will perform on the road, air flows and temps under the bonnet will be different, and the engine may behave exhibit transient behaviour under acceleration that is different to the behaviour you'll get while you're holding it at constant load.
As a case in point, I spent a couple of days trying to track down a running problem with a friends car. Occasionally the engine seemed to gag slightly in top gear, but it was hard to reproduce. This was a supercharged 5.2 in a light Ginetta and it went like stink, it was a championship winning car and routinely came first in class on the hills. But it had a slight hickup and after a couple of years it was decided we should really get to the bottom of it. Eventually we found that the jets had been installed wrongly and the engine was overfuelling at the bottom of the rev range, underfuelling mid range and then overfueling at the top. Occasionally it would stay in the middle of the power band long enough to lean out and go flat. But because the performance was so ballistic it was very rare for it to stay under those conditions for long enough for the symptoms to occur. The throttle pump chucked in enough excess fuel to keep it going until it was past the problem 99% of the time
Obviously like this the engine was a long way from its full potential, five seconds on a rolling road would have shown the problem immediately, my point is that the transient behaviour was so different to the steady state that even a huge problem like this was barely noticeable.
Given the choice a dyno is obviously the preferred way to go, money permitting. But that doesn't mean you can't get a satisfactory map on a real road where full power runs are feasible, and you don't actually need a dyno to tell you how much faster your car is afterwards. That's all I'm saying.
What I disagree with is your assertion that you *have* to use a dyno to do the job properly, or that you have to use a dyno to obtain before/after measurements.
If you're able to take the engine through the full rev range at full throttle then you can map it on the road, it just takes much longer. That isn't going to be practical in some cases but in cases where it is practical there's nothing wrong with it if you don't mind taking a long time.
Mapping it on the road might even give you a more accurate map under some circumstances. Dynos aren't completely representative of how the engine will perform on the road, air flows and temps under the bonnet will be different, and the engine may behave exhibit transient behaviour under acceleration that is different to the behaviour you'll get while you're holding it at constant load.
As a case in point, I spent a couple of days trying to track down a running problem with a friends car. Occasionally the engine seemed to gag slightly in top gear, but it was hard to reproduce. This was a supercharged 5.2 in a light Ginetta and it went like stink, it was a championship winning car and routinely came first in class on the hills. But it had a slight hickup and after a couple of years it was decided we should really get to the bottom of it. Eventually we found that the jets had been installed wrongly and the engine was overfuelling at the bottom of the rev range, underfuelling mid range and then overfueling at the top. Occasionally it would stay in the middle of the power band long enough to lean out and go flat. But because the performance was so ballistic it was very rare for it to stay under those conditions for long enough for the symptoms to occur. The throttle pump chucked in enough excess fuel to keep it going until it was past the problem 99% of the time
Obviously like this the engine was a long way from its full potential, five seconds on a rolling road would have shown the problem immediately, my point is that the transient behaviour was so different to the steady state that even a huge problem like this was barely noticeable.
Given the choice a dyno is obviously the preferred way to go, money permitting. But that doesn't mean you can't get a satisfactory map on a real road where full power runs are feasible, and you don't actually need a dyno to tell you how much faster your car is afterwards. That's all I'm saying.
Given todays roads etc....mapping cars on the road is a risky business.
But not everyone has the luxury of a dyno. But it IS the best place to do the bulk of mapping, simply because its the safest, most controlled enviroment.
Driving on the road, afterwards, to ensure all is fine.
That said....I always map mine on the road....can ya imagine how much fun that is
But not everyone has the luxury of a dyno. But it IS the best place to do the bulk of mapping, simply because its the safest, most controlled enviroment.
Driving on the road, afterwards, to ensure all is fine.
That said....I always map mine on the road....can ya imagine how much fun that is
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