Should you remap a car on the road or on the rolling road?
 

Have been reading up on the subject as im about to get work done on the WRX.

Lots of pro's and cons for each method according to Scoobynet.

I then read an article in Japense Performance Car magazine about the American guy who train's mappers (people who map ECU's that is) who says you should only ever map on the rolling road.

Who's right?

Jza

Have a search. This was done in detail quite recently.

Yep done the search?

Jza

do you plan on actually driving the car on the road or just run it up every now and then on the rollers to show how much power it has?

The general conscensus amongst all the respected mappers seems to be that it needs to be at least finished off on the road.

If the mapper has access to a RR then it can only help in set up before going out on the roads. If this saves time hooning up and down the roads then fair play.

My own personal opinion is the same as Riggas. I would not entertain my car being mapped purely on rollers. I see enough errors (late spool, low boost etc) on RR print outs on my own car that i really cannot see how the car can be mapped as accurately.

When all said and done, you drive it on the road - So it needs to be mapped on them. All IMHO and some mappers will disagree.

My Sti v3 has been mapped just twice, both times by AndyF.
We used the Apexi FC starter map and then mapped on the local A roads, and a good long Bye-pass.
There was no drama, no heroic (?) fast charges screamming through the gears, but solid tuning with no fuss.
It made 380 bhp x 360. on PS's RR about 4 months after mapping (just a simple power run, no mapping)

Second mapping after the FMIC and the same again but with much more boost. Haven't been to a RR since as it goes faster....

A road map must be the best as it is real-world?

Worked for me.
But AndyF was the mapper...

Graham

just to add my car was mapped by simon roe ( jolly green monster on here ) with a power fc,very straightforward procedure and everything was sweet as a nut....... went to a rolling road day very recently with a lot of other impreza's and they were all shown to be running very rich,now some of these cars had been mapped at powerstation and by andy f and jgm and i cannot see any of the above mapping the cars to the point that we saw on the printouts that day,not matter how good the set of rollers i doubt it can accuratly replicate the loads that are found on the road when driving..... i would prefer my car to be mapped in its every day enviroment where its going to be used.

martin

The most important consideration by far is the mapper. Then it's whatever method they prefer. I don't know of any that don't at the very least advocate road testing the car after mapping on the rollers!

Mine was mapped on the road- it's absolutely brilliant!

Ns04

Mine too was mapped on the road. Twice, and both times has been awesome.
Well, the second time i expected to feel like 7 million HP but now i have got my head around it i am happy! :)
But i would still like to see it on the RR just for the bloody figures TBH.
Now since last week i have Defi gauges installed i can see that mine is peaking at 1.3 bar and no spikes, overboost, etc, etc so i dont see any need for it to be mapped on the RR.
I can see why the RR is awesome for diagnostics, and for trying different things out and then checking the power, as in 'Project Phoenix' in Jap mag, but again imho the only ppl i would let map my car all do it on the road, so they cant be rubbish can they?
And all 3 of them are the top mappers in the country, again imho, so i am happy :D

Less than a year ago, I would have said that it has to be mapped on the road as that is where the car is used and conditions on SOME rolling roads do not reasonably replicate road driving conditions.
I am now of the opinion that there are potential benefits from using both rollers and road for mapping.
Putting in the initial map on the rollers is likely to be quicker, use less fuel and create less stress on the engine. That map can then be perfected on the open road, particularly for things like acceleration enrichment and some boost perameters.
Maximum power can be found on the rollers quite easily. Not so easy when you are travelling at 150mph plus where max power is on quite a few Scoobs now, with a lap top on your knee and do not have the advantage of the RR information/screen. Apart from anything else, except on good road surface, the vibration and buffet is such that the screen may be unreadable. Travelling at these speeds is illegal, often stressful on the mapper even with a capable driver. What about traffic and the dangers and isn't it illegal to exceed 70 mph?
For these reasons I think a combination is the way to go but of higher importance is the mapper/s ability in the first place.

My opinion is that you tune on the rollers if the 'pub talk' peak power number is important to you, you will always make more peak bhp 'on the rollers' if tuned on the rollers.
Tune on the road if the actual performance on the road is your priority. I realise that the location of some tuners can make this difficult for them.
If it is a track car that will see high speeds such as 150mph then there is no substitute for tuning on the track.
Subarus differ from some other cars as they have a mass air flowmeter, this is particularly sensitive to the way the airflow is presented to it and the real life airflow conditions to the air intake can only be replicated on the road. Any car with a TMIC will also not be able to achieve the charge cooling that it would on the road.
It is not unusual for a rolling road to show the air/fuel ratio as being way out when being tested. Subsequent checks under road conditions show the real reading.
I had a number of RR shootout attendees come for a check recently when I was down in Manchester, all checked out fine despite having been told earlier in the day that their cars needed urgent attention due to RR AFR figures.
Now this may just have been someone touting for business but imagine if the engine was tuned to this 'false' rolling road AFR reading and then set free on the road. The power output and possibly reliability are going to differ somewhat.

Andy

Agree with Andy 100%..

Simon

If the cooling arrangement is effective from a flow and distribution aspect then the engine really doesn't know if its on a road or a roller...TMIC cars are not an issue on our rollers as we simulate a 60mph flow with additional water spray.Typically I can hold no more than 20Deg above ambient even when holding the engine at fixed rpm under boost during mapping.

Procedure is all important. During power runs the waste gate duty will need to be adjusted to achieve what will be experienced on the road.That is we will remap the duty by holding rpm at full throttle after the final power runs to ensure that "road" boost will be identical to "roller" boost.This is the most common complaint when cars behave differently on the rollers, but with correct procedures it is not an issue.

I don't believe you can optimise the map on the road.Unless you have unlimited supply of brake discs and pads you simply cannot fine tune all the load sites without being able to hold the RPM and vary load.The best you can achieve is by left foot braking for a few seconds at key sites, but that is all.
The proof of this is the number of cars we re-map and significantly improve that have been road mapped;and I include myself in the original mappers.This is particularly noticeable on AVCS cars and cars using race fuels that do not exhibit det limitation, but is true across all models/ECUs/mappers etc..How can you know the valve timing is optimal if you cannot get a "snapshot" power reading at a particular load site.Sure you can do an acceleration run over a fixed rpm interval and measure time elapsed, but this is an average at best and is subject to the vagaries of road conditions, wind direction etc.I can hold the engine at 5000RPM, full boost and log instantaneous power; then adjust VVT/ign/boost and re sample until we get the max.I would submit that this is not just "pub" numbers; I think it is using an expensive tool to get the best out of the engine.

Once you've saved your pennies I'm sure you'll agree....

Steve

You have saved me the bother of raising that issue Steve.
If you need to run a different WG duty on the rollers what does that tell you ?
Its obvious to me that you can't replicate the road conditions.
If you have to run increased WG duty on the rollers then you will increase the exhaust gas backpressure, this will affect the engines timing sensitivity, partly due to the extra exhaust gas retained in the chamber after the blowdown phase.
That is just one reason that cars tend to 'det' on the rollers when they are fine on the road or track.

Andy

Andy,
We can replicate road conditions quite easily as I explained.We can alter the acceleration ramp to exactly replicate the ramp speed in any gear on the road and hold the rpm and adjust the WG Duty to ensure that road boost is the same as roller boost.That is the car will leave the rollers with the SAME WG Duty value as it will have on the road.We map the car in this configuration so there would not be a det problem that you have seen (or heard of?).The WG Duty in some case (depending on Turbo size etc) would be adjusted if the Power run mode was not giving the boost that would be seen in say 4th gear on the road. This seems to be a sensible approach to ensure that the resulting power figures are valid.Bear in mind that we are only talking of WG duty adjustments in the order of 5%...Increase in back pressure at this level? I don't think so; particularly as we often REDUCE the WG duty on the power run....

Steve

I am a declared confirmed road mapper, rollers have there place for diagnostic and a certain amount of full throttle work but thats it, I have mapped all methods. Given the choice I would setup on the road, its b*ll*cks to say that puts more stress on the engine, less since load impedance and cooling is real. Then stick it on the rollers and work at the full throttle stuff if needed.

Whatever anyone claims, and those who have invested large amounts of money in rolling roads will always try and get a return on their investment, you can never get a car to optimum on the rollers.

A well mapped car is not just about mashing your foot to the floor, few people drive there cars like that under normal road conditions.

The number of remaps of roller mapped cars I do is testament.

This will always be a debated subject as it has been recently on here.

I have known engines mapped on the rollers or even engine dyno by spotting destroy themselve the first time they are used in anger on the track.

Steve before you can even attempt all this replication, for each car you must have been out on the road, since you can't get that info without mapping it what does that say ? that you have to map on the road !!! There is no black art, its plain and simple, all these cars are different and you cannot read anything across.

Just my contribution to the debate, think this thread is going to get quite enjoyable.

cheers

bob

I should have said, more stress on the car but I do not agree road mapping is less stressful on the engine than on an efficient rolling road where temperatures are well controlled.
Mapping on the rollers takes less time to get the map somewhere near than it does on the road, there are no aborted runs because of traffic, there is no standing on the brakes, less fuel is used so I think there is less stress on the car and engine, assuming the rolling road facility has proper cooling.
Not everyone has your experience and dedication Bob, to spend the time refining maps as we have done in the past. There is no critisism of your results implied or intended.

Surely the ultimate result comes from a combination of rolling road and real road.

Andy : You have used several rolling roads for tuning. Did you not ask TEG Sport about the use of their rollers. That indicates you are also aware of the benefits of using a combination of both.

Of course I have used them Harvey, how could I comment on their unsuitability otherwise. I would have thought with your experience of RR days you would appreciate where I'm coming from.
The fact that steve has stated that he sets a different wastegate duty to enhance power results just confirms that RR shootout days are a load of rubbish. The majority of guys turning up and running their 'road' maps don't stand a chance of a fair comparison !
For someone just setting up as a mapper, or someone doing a wide range of different car makes, I can see the benefits of a RR. It will allow them a faster setup of a base map.
I (and I'm sure Bob) have hundreds of base maps for the Impreza and as such we are in the fortunate position that the majority of the mapping time can be spent on the final stages of map refinement on the road.

Steve, perhaps you can explain that in more detail. On the road, a car will accelerate at different rates throughout the rpm range depending on the torque output and aerodynamic drag at that particular point. The torque is dependant on boost, which again is partially dependant on acceleration rate.

Can you recreate a variable ramp rate proportional to the vehicle weight and torque output with compensation for increasing aerodynamic drag ?

Andy

Excellent point Andy,

Not unless a manualy controled run is done, and then you still have to know what rate is to be used where, which is different for each gear, which is ... oh well you know the rest, so once its been sussed on the road in order to do the dyno runs ... damn mapped again !!

For sure I am very fortunate to have mapped the number of cars I have, as Andy says having a large database covering all cars in a myriad of mod states using a wide range of engine configurations is a huge plus absolutely negating the need for any "rough cut" setup at the start. You can get straight into the detail.

Steve has just said that he can replicate road conditions with the rollers, so the stress cannot be less, more in fact since its tethered and not free, cooling is also never ever matched, under or over its wrong both ways, axial fans produce flow but no pressure, centrifs pressure with restricted flow, neither can truly replicate a vehicle moving at speed through air. There are many claims made about how good rolling road cooling fans are, truth is there is only one thing thats right and thats the replicated airflow you get ... on the road.

Bob

Too true.

I hope the debate continues. It makes a change to have some threads actually worth reading!

Err, hmm, I think you are right jasonius as it was early when I posted! LOL.
Let the debate continue i say. It is nice to get so many expert opinions in the one thread and actually discussing it too. Superb.

Road - period ... that's where we drive

If you are after figures to brag down the pub with then just lie like they do and enjoy your car that has been mapped to suit its proper environment. :D

Quote - Mike Wood from Prodrive discussing a MY06 PPP car.


You could charge money for results like that ;)

Andy

I see this ones going again....lol
I have always held the view that to do purely one or the other is just not using the tools at your disposal...
I have seen cars tuned by most of the road mappers on this site and the MLR on our DD rolling road and it wouldn't be fair to say that they were all bad...
That said it also wouldn't be fair to say that they couldn't be improved upon if they were fine tuned by the same mapper on the rollers....
Some of us invest thousands of pounds buying these things to be used by customers and tuners alike...

Are you trying to say that a rolling road mapped car wont be as good to drive...
If so come and see me and I will prove you wrong..
I have never had a customer of mine say that his rolling road mapped car is undriveable in the real world..

Not entirely what I am saying but....

Essentially there are two different environments and both have their advantages. But, the RR is not real driving and there are always other factors that cant be tuned for on the dyno.

I am no expert so please dont shoot me down in flames, but I would have thought you could get close on the rollers but not quite there. I would have thought that all RR mappers do the finishing touches on the road to test/tweak it in the real world.

I am nothing more than a driver here, mapped by AndyF on the road.
On the road you give the mapper real part/full/feathered throttle and all the real driving conditions for the mapper to 'average' and then optimise.
This is not a quick process, we took about an hour on a dual carriageway humming up and down at reasonable speeds.

I hillclimb the car as most on here know, and part throttle, full etc are all very real to me.
If such an approach means that Andy has not found/set the last drop of output, so what?
My engine has run so well, so smoothly and so RELIABLY despite me giving it death many times while stinking hot, tolerating fuel surge and lots of red line bouncing, missing gears etc and then I cruise home and park it in the garage.

I only know well one other Impreza driver (and hillclimber) who had his RA mapped (Gems) on a RR and it was ''crap'', his words not mine.
It eventually got road mapped, and while the high speed runs down country lanes scared him sh!tless (quote) that car was just so good. I had the joy to drive it on a track, just so good.
Different mapper mind!

I'm like some here, not too interested in max numbers, but VERY interested in how it actually drives and will it enable me to win the class?

A great thread, one of several on Snet currently, so good to read the veiws of respected experts, so refreshing.

Graham
:D

Wouldn't dream of it....:lol:
I have always maintained that to be absolutely assured of getting the best results you have to do both..
I'm sure the road mappers will say piffle (lol) but they as we are bound to promote their own way of doing things , it is after all how they earn their living..
But don't forget it's easy to say that they don't need a rolling road when they cost £70,000 , but how many would say they still don't need one if they only cost a fiver...:thumb:

I can only really offer my opinion as a consumer and, I might add, not one with a particularly good working knowledge of mechanical, or electrical engineering, nor physics, nor thermodynamics, nor any discipline related to engine mapping :D

However, I think the most relevant scientific concept (that I do have an understanding of) here is that of 'ecological validty' i.e. to what extent do the conditions under which a stimulus is tested faithfully replicate the conditions of the real world conditions in which the stimulus exists/operates.

My understanding is that cooling is critical to a turbocharged engine's performance. I have yet to see a pursuasive argument that a RR can replicate the characteristics of the airflow that occurs when driving your car in the real world. Thus, in this important respect, road mapping would appear to have a clear advantage.

Moreover, having listened to these types of threads. I've heard people point out that:

- Cars mapped on the rollers can often exhibit behaviour on the road that is markedly different i.e Even to the extent that a car well set up for one environment might exhibit det on the other.
- Results are incomparable between different RR's and even the same RR can produce variable results.
- Cars that produce good figures on the RR, can often show a noticable disadvantage compared to the same model cars, with equivalent mods and "apparently" very similar outputs that have been tuned on the road (assuming the confound of driver skill is removed). I have experience of this personally.
- Cars that produce good figures on the RR can sometimes go on to dissapoint in terms of their performance in competitive events (assuming the confound of driver skill is removed)
- An operator can significantly affect the output of a RR

That is not to say that I can't see where RR come in handy, especially for those who may not have Andy and Bob's years and years of experience and data to formulate their base maps. I'm guessing that certain parameters may be easier to set more precisely initially on a RR where you don't have to worry about things like the articulated lorry in front of you!! I would imagine they are also a very efficient way of diagnosing faults. I also know of several tuners who use RR and have a string of very happy customers (i'm pretty sure most, if not all, of them would advocate a road test after, though). Finally, although I don't participate in it myself, I can certainly see why people might like to compare their car's outputs to those of others as a form of competitive event. :)

At the end of the day though, the only comparison that matters a damn for me is how the car does in the environment in which its driven. i.e. the road! This takes us nicely back to the point of ecological validity i.e. where we started!

If you know someone who owns a car which produces more power than yours on a RR, but struggles to keep up with your car in a straight line then which outcome has the greater relevance as a performance measure?

I suspect that RR are like any other tool; they can be used and abused. Furthermore, I suspect their outputs are like any other statistic- they are subject to assumptions/conditions/qualifications. If you understand these then you can exercise a sound interpretation of the results. If not, then you stand to be misled!

For the most of us mere mortals, I would argue that the "Bum dyno" is the best and most meaningful measure. . . . . . . . . . . .

Albeit not very scientific! ;) :D

Ns04

P.S. Bob mapped mine; chuffed to bits with it doesn't quite do it justice!

https://www.scoobynet.com/midlands-2...october-4.html

worth a read