I must be a bragger then! :D

Personally...... mine will do the bragging on the black stuff! ;)

Regards,
Shaun.

ditto!!!!!

A real dyno sl@g :p ;)

you might be dissapointed with the harsh reality of the blackstuff ;)

You think so! ;) ;) :D

Better to have it mapped for real conditions, ignoring the fact that you need your own private test track for this. Having done plenty of rolling road time before, on lots of different rolling roads, and also having got weird results, overheated engines, blown up engines, turbo heatshields catching fire, climbing out of the rollers, spinning up the rollers etc etc, I'm firmly of the opinion that rolling roads are of limited use.

The worst thing about them is the lack of realistic airflow. There is no way any fan, however big or well positioned, is anything like road air flow at speed. On a turbo charged car this is absolutely crucial.

dunno whos been mapping your cars!!

If you came to me with what was a good setup, and were after some tweaks looking to pickup small amounts of power. Mapping things like cam timing are much easier on the rollers, also light load mapping is very easy on rollers, as you don't need to rely on the driver nearly as much to keep in the load or RPM points. If I was mapping a car for the first time with a on-the-fly mappable ECU I would prefer to do the bulk of initial mapping on the dyno, but there is a cost involved. If it was a high power car that need some mapping in the height of winter, i would also use the dyno, backed up with runs at somewhere like Brunters. Swapping ends in a straight line when you plant the throttle at 70mph is not nice.

Dynos are good for finding small gains, it's a very controllable environment in terms of load. If however, you wanted to specifically map for top speed runs or sustained high load, I think I would take the road. Also the road is good for picking up transients. But rolling roads are getting better all the time (well the control and software mostly) and with enough airflow, i think road mapping has a limited lifespan for most (but not all) applications, simply as it will become the most cost effective way, especially if the current trend with speed controls continues.

Please remember, that like I mentioned before, mapping on the road is stil my usual method, largely my preference, and currently cheaper. It doesn't mean I don't like the dyno for certain things.

Paul

The trick is to use them in the correct manner, and to know when they are not giving you the info you need. It is possible to get fans that DO provide near road airflow conditions. And ultimately if your dyno conditions correlate to some road conditions, they are at least valid for that. The flip side is that if you want to map a car for running reliably in the height of summer, then you need to map it in the height of summer if you're doing it on the road. You can get a reasonable (ie better) guess of what's going to happen by carefully running it on a dyno with some form of temperature regulation (ie adjust fan flow to get air intake and water temps you come to expect from experience).

At the end of the day, a dyno is a tool, and like every other tool, they can be used, abused and blamed.

Paul

Well said..

Im also with paul, dyno mapping has its uses in places. I do think a combination is best.

Especially when my ECU came with a table full of 0's when I bought my autronic there was no such thing as a get you running map! - Yet we got it running on the road :o

My current preference is get it reasonable on the rollers, and iron out any problems.. any probs like problematic boost hoses, then you stop the run, get out.. tweak or fix.. on the road you may find yourself sucking the dust of the road :rolleyes: :mad:

Once your about right, roll out of the workshop to a deserted bit of road, and abuse the road..

So for me, rollers then road.. and if your a tart, wack it on the rollers and do a power run after.

David

Is bragging about bhp much different to bragging about 0-60 times and quickest std UK engine? ;) :D


Join Date: Jan 2003
Location: 0-60mph in 3.73secs, 0-92mph in 7.5secs, 1/4mile in 11.7secs@ 119mph. Quickest std UK engine?
Posts: 4,356

WOW James

totbv then?

:D

I was expecting 4th to be the gear of choice for the bulk of mapping (full boost for long period) but to ensure best performance in each gear with differing boost targets I thought it would be necessary to do at least a few runs to near max rpm through the gears.

---

My car is booked in with a respect mapper - to be done on the road.

My main concerns when it was suggested that mapping on the road would be best are that I can imagine it is difficult to fine tune over the entire rev range. I can see how it would be easier on the rollers to tune at particular rpm increments for a particular load. My car isn't that highly modified, so I don't think I need an initial rollers run to get that basic map to work with on the road.

Another couple of questions that I could do with some clarification on - considering my car is going to be mapped very shortly, is there anything to bear in mind come summer time? Will my car be optimized for winter conditions? Is there a best time of year to get your car mapped for all year round use?

Also with ECU 'learning' is there any truth in the statement that after a car has been mapped it will then gain a bit more power again as the ECU optimizes further - or is this negligible?

Finally, any tips for me come meeting with the mapper? I'd like to be able to retain good (relatively) fuel economy on cruise but want a more aggressive (classic) power delivery? Can the mapper accommodate differing preferences or is it best to just let them get on with it – is there generally one optimum map for each car and that's it?

Those questions are best aimed directly at your mapper. How a mapper chooses to load up a car is down to him, ultimately they will try to replicate as wide a range of engine conditions as possible. They should tell you exactly what they want you to do as they progressively map the car. The important thing is to listen to what they ask, and remember you are trying to map the car, not race it.

Paul

If he doesn't ask you how you mainly drive the car and what use you put it to, ie track day/daily driver/1/4 mile racing etc then make sure you tell him !!

The car should be mapped to cope with all eventualities but can be biased towards your particular requirements.

Andy

Oh, and if you want a dyno queen, go get it mapped on a dyno ;)

Which works great until your "I don't ever rag it" customer boasts how well the car runs after the remap when they were racing another car at a sustained 160mph :o

Paul: Mapping on the dyno doesnt sound like it would be of any benefit to me.

James: Thats not bragging - thats proven performance ;)

Bob, I find that quite interesting since you have already done some of your own mapping on a rolling road. But instead of making changes with a laptop, you made changes with a can of methanol. If you tested your car with a slight change that you felt sure would improve the performance of your car, but it consistently made 10hp less accross a wide RPM range, would you then go and try it on the drag strip? Given your interest in drag times, you are in a prime position to exploit the feedback a rolling road could give you. Being faster is obviously the aim, but knowing the power difference between 2 different setups allows you to make informed decisions about the changes you make.

Paul

Paul, I went to WRC Tech RR for a diagnostics to try and find out why I had a poor idle. No mapping. As you know RR figures can change by 10bhp from one visit to another without any changes. If I was to make any changes to the car the place to test them would be the drag strip.



Bob

Your missing the point. When you begin to test on the drag strip, the drag strip becomes a dyno. The difference is, the rolling road doesn't car whether you messed up the launch, or it's damp and you have no traction, or you missed a shift. The rolling road doesn't make you queue for up to an hour between runs. The rolling road doesn't make you conduct your testing for the world to see. The rolling road can be open during the week. The rolling road doesn't require you to agressive launch your car each time you want to make a comparison. A rolling road wont get you a speeding ticket.

Conversely there are reasons why testing on the 1/4 mile is preferred, but to preclude yourself from a very valid and valuable resource is a bit short sighted.

Paul

i dont drive my car on rollers, so i dont see why it should be mapped for them :confused:

I pretty sure I know what to expect and how to get the most from the mapping session.

Thanks Andy, Paul, Shaun and others - great advice. :thumb:

Not too worried about the dyno figures - but it will be going on one after for a power run all the same. :D

Ben

What gear is your car mapped for then? Is your car mapped for primarily downhill or uphill use?

It's been said before......Choose the mapper you would like to map your car as this has more influence than anything else :D

Shaun

Yea and if its Paul, make sure he tests it uphills AND downhills ;)

Errrr.... I tend to use my car on a flattish sort of road :D

Black colour with white stripey lines in the middle only in my case scattered with slow cars / ASDA lorries which impeed progress.......LOL

Shaun

It's OK Shaun, Your AVC-R was actually set up running behind an Asda Lorry on a level road, you can relax ;)

I understand your viewpoint. I'm not saying that a dyno is without its uses - just that it isnt a benchmark for any 'gains' for me.

Gains on the dyno dont mean gains on the strip.

I'm more interested in 'how fast' not 'how powerful'


Bob

You miss the point.

?

Your RR launch date? ;)