Road Mapping VS Rolling Road

Hey lads, This may be of no interest to a lot of people or people have their own opinions and it is a highly debated topic but considering the rolling road day starting now in a min ( Im late ) it may be of interest. This is only one side of it,. Rolling road days are a great day out and its very interesting to get an opinion on how the car is running and what power its making and where its making it but people often don’t get the results they expect on the rollers considering the spec they have and get a bit disappointed. This might make you feel better if you do get less then you thought

There are 2 sides of this of course and the people who own and map using rolling road disagree to a lot of it so again its opinion based really, But considering a lot of us have had our cars road mapped rather then on the dyno and the fact that a lot of us are mapped by Andy Forrest I thought these quotes may be of some interest.

At one stage when Andy was over we were speaking about how in the magazines where they do the rolling road days in the operator’s comment part it will often say running rich or needs a remap etc etc but really its because its set up ( road mapped ) for the road and runs as it should on the road but the rollers see it different a lot of times.

This is part of a debate going on at the moment. First one below is Andy.

“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.

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.


The fact that that 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.

Any car using an airflow meter such as the Subaru (especially if it has an induction kit fitted) will run totally different on the rollers to how it will on the road.
Why do you think the AFR changes when out on the road ? it's because the primary load reference value has changed. When this changes so does the ignition timing, so you can fine tune all you want on the rollers to get your desired bhp numbers............just be sure to go out on the road and do it properly afterwards “

Andy Forrest


"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.

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.

I know of one owner who was told his car was producing 77 bhp and 70 odd ft lbs less than it previously recorded on three different rolling roads and repeated again on one of them after being dynoed at this establishment. This car had been mapped on the road btw not on the rollers. The proprieter advised that the only cure was to remap it (lol)."

Bob Rawle


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

When we ran the car on another well known dyno dynamics rolling road we got 310bhp on the first run and over 325bhp on the last one, all without changing anything on the car!

Mike

Now this man seems to have anticipated the theme of the day well in advance.

Having spent the day watching road mapped car after road mapped car hit the rollers and then to see disappointment time after time from people who had been well pleased with how their cars drove on the road only to find they were performing under their expectations on the rollers, I couldn't help but wonder if people had forgotten what is actually more important.

Not one person the whole day took one look at a torque figure, and needless to say nobody seemed to care where the torque was happening either. All that mattered was headline power figures, which are utterly irrelevant to how a car feels and drives.

Andy Forrest is going to have to listen to a fair few complaints arising from today in circumstances where yesterday he was walking on water.

Rolling roads are great for science, I learned today that I can increase my horsepower by 20 HP and max torque by 5lb/ft just by throwing about ten litres of 102 RON fuel into a half a tank full of 95. Interesting, and the sort of figure I could never have noticed subjectively on the road.

Really though, that's what a rolling road is good for, diagnostics and base maps. Top tip, as I have said in several previous posts, if your car is running right and you're happy, don't take it near the rollers.

One question, where do we drive, real roads or rolling roads?

[quote author=FQ 340 link=topic=829.msg6758#msg6758 date=1163890471]

Really though, that's what a rolling road is good for, diagnostics and base maps. Top tip, as I have said in several previous posts, if your car is running right and you're happy, don't take it near the rollers


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Nail on the head IMO. I dont roll my car mainly because Ive very little intrest in the number and most likely being told how rich its running although it is nice to get a figure and it is a great day out. The last time I was on a rolling road was when I had a full exhaust system and td05 and had 265bhp / 260lbs or around there. Since I done a fair bit more ( manifold ,FMIC etc ) but never felt the need to put it on rollers because it feals good / fine on the road so that does me. Now a rolling road day is a great day out and most likely I will run my car next year just to be part of it all and take part in the day more. but thats all it will be. Road mapped cars show less on the rollers then they really are and as Andy sais cant compete with cars that have been set up on a rollers for a peak figure. I know of one rolling road place that show you the nice figure on the RR then take it out on the road and have to adjust it back. But they have a happy customer. More quotes below.

Andy Forrest below.

“I have no idea what power it would produce on your rollers then you are 100% correct. I have 100% no idea and I 100% don't care ! If I thought numbers on a roller were important don't you think my Impreza (with somewhere around 800bhp) would have been regularly presented to a RR to gain kudos ?

In addition to all the above I can actually feel how smooth the throttle transitions are and I can monitor in real time under real conditions the effects of acceleration fueling enrichment and transient boost control.

On Ecutek cars where the in gear compensations for wastegate and target boost have been enabled, I can set up each individual gears targets. This allows improved acceleration in lower gears without overloading occurring in a high gear. This function alone is a good reason not to dyno these cars, you cannot replicate the acceleration rate achieved in each gear and hence you will confuse the ECU. This will result in under/overboost and the associated errors in measured power.

In a nutshell, I have all the info I need to make the car accelerate as fast as possible for its spec, safely improving the acceleration rate is my no1 priority, not a number.

The UK's fastest accelerating std internals 2.0 Impreza shows only 340 bhp on a DD dyno yet other cars claiming 400+ cannot get anywhere near this acceleration rate.
This is not an isolated case, I refer here to everyday road cars that visit the strip from time to time, all the 11.** sec, std internals cars were road tuned and none of them will impress on the rollers. Suits me fine”

Andy Forrest

"Both are mapped at fixed rpm intervals. Approximate setting, real life conditions can not be achieved because in reality the engine is accelerating at a dynamic state. This means that the engine load is transient and not performing at a constant steady rate. Map will be slower on the road than the cars actual acceleration rate (although the rolling road derived map may well produce bigger numbers on the rollers). A car optimized on the rollers will only perform to its capabilities on rollers and not the road. RR are great to get the general shape of the fuel and ignition maps. But wont provide a final map"

Cant remember who this was.

the above does make sense..i got a crap result and was told my car was overboosting,my clutch may be f00ked then was told the solinoid could be dirty,then my diff lol...the car feels spot on on the road and as andy said when he mapped it,it reacted very well to the map..so im happy with that..

Fair point, Car feels spot on but I'm a tad worried about the activity on my knocklink since the car was mapped. I had no activity previous to that so something must be off.
Cheers
John

[quote author=deco c link=topic=829.msg6812#msg6812 date=1163947939]
the above does make sense..i got a crap result and was told my car was overboosting,my clutch may be f00ked then was told the solinoid could be dirty,then my diff lol...the car feels spot on on the road and as andy said when he mapped it,it reacted very well to the map..so im happy with that..
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Deco I remember on the way home with Andy he commented that your car was the best of that day and reacted better then another STI with front mount over the weekend so I wouldent be to bothered if your happy with it on the road.

@ Johnm

have you got an oil catch tank fitted? if you havnt then when you increased the power of your car by getting Andy to map it you also increase the blow-by oil and gases. these will reduce the octane rating of the fuel in the cylinder and can cause det.
if you havnt got a catch tank you should get one and then see how det. is.
if that fails get Andy to look at it again.

George

[quote author=JohnM link=topic=829.msg6814#msg6814 date=1163948359]
Fair point, Car feels spot on but I'm a tad worried about the activity on my knocklink since the car was mapped. I had no activity previous to that so something must be off.
Cheers
John
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Yeah I wonder what could be up with your car, The first day you got it mapped on the way home say was the knocklink lighting up ? Or could the knocklink be set low and detecting any other engine noise  :dunno:

Also without a catch can the oil can make its way back into the inlet manifold and thats where the det could be from.

Damo to be honest the day I got it mapped I wasn't driving it that hard, the power FC is detecting it also and registering quite high on it- filling it at some stages.
Fookin puzzled
Cheers
John

@ Damo

your right thats what i was saying. when there is no catch can fitted the oil and gasses from the breathers are returned to the inlet manifold and from there into the cylinders where they mix with the fuel and reduce the octane of it causing det.

@Johnm

have you got a catch can? if you dont you can remove the main breather and run a long hose to it and vent to atmosphere. and temporarily block off the return to the manifold with a blanking plug or right sized bolt. then drive the car and see if your still getting det.(you must give it a few miles 1st though to clear any oil that is in the manifold) if that works invest in a catch can. if you like i can do it for you when your collecting the afm cover.


George

THanks George- I'm on the case
Cheers
John

No bother

George

one other thing John.

just make sure you use a really long piece of hose- at least 2m and loop it around up high in the engine bay before down low in the transmission tunnel to atmosphere. that way you wont get oil pissing out of it and destroying your engine bay. just the the blow-by gasses

ah its defo a different car than before the map so im happy enough.theres pleanty of people who get very high figures too on the rr as in 340-350 bhp with just decats and minor mods,as andy said on the day its how the car drives not the pub talk figures..

Very true Dec, I'm delighted with the performance from the car.
I'd just like to get a ball park figure on what she's putting out.
Cheers
John

I've read all the above but none of it answers my problem as to why my car produced 22 bhp and 16nm less on the TD04 hybrid over the standard TD04!

It might be reduced octane because I've no oil catch can, maybe its the gear dependant boost control or maybe its something else. I'm just baffled. She drives fine and there's no detonation. I've e mailed Andy Forrest with a few questions!

Oisin I have to correct you when you said not one single person was concerned about their torque figures. I recall discussing with you that my car was down on torque but reaching peak torque of 344 nm at 3750 which is very low down the rev range for an impreza and that I was happy enough with that. I've always maintained that BHP figures are pretty irrelevant. Dont believe me? Have a dice with a BMW 330d and be prepared to work that gear box hard!

Frawls

[quote author=FRAWLS link=topic=829.msg6936#msg6936 date=1164049029]
I've read all the above but none of it answers my problem as to why my car produced 22 bhp and 16nm less on the TD04 hybrid over the standard TD04!

It might be reduced octane because I've no oil catch can, maybe its the gear dependant boost control or maybe its something else. I'm just baffled. She drives fine and there's no detonation. I've e mailed Andy Forrest with a few questions!

Frawls
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Hey Dave, Your one is a puzzle and really sounds impossible to lose 22bhp and 16nm when going from TD04 to a Hybrid TD04. I think I mentioned a guy got AROUND 330bhp out of one a couple of weeks ago which is the highest yet but most are geting 300/ 300. The gear dependant boost control that the newage Denso ECU has defo confuses rolling roads and Andy warned me about this at one stage. But I cant see it being that far out, Normally it shoots the boost or doesnt make it's target boost and cant be run at all. Maybe a second run on another rolling road to see if its the same thing and if so there has to be something wrong somewhere.

Frawls the reall question that needs to be answered
is after fitting new Turbo etc how did you feel about the cars
performance once mapped. ??

A loss or gain of 22bhp & 16nm would be easily felt i would think.

Where was the car Rolled for the first results ???

Niall.

Frawls,

You're quite right, you and I did discuss your torque figures at length, sorry should have been generalising. In my defence though, you were the only person that I did discuss torque with and nobody was keeping a log of the torque results nor the points that torque was coming up and peaking at in the range.

The thing is, as you know, rolling roads only actually measure torque and then do the sums to produce the HP figure, which by definition happens high up in the rev range. I personally am only interested in the torque curve as that is what will tell you how a car drives while also giving you the HP figure.

As for your loss in torque and HP, my guess is that it is solely down to the fact that the car was road mapped. Your losses sound like a big drop but there could be a huge amount going on in the background.

My own car produced a 20 HP and 5 lb/ft gain over when I ran it two months ago on 95. The only difference between the runs was the addition of about 10 litres of 102 RON fuel to a half tank of 95 and an ECU reset.

Driving the car, the power difference was imperceptible. The car did feel smoother and more responsive, but up high, I really didn't think there was any difference. On the rollers however, there was a clear 20 hp gain.

Boost was also up all the way across (1.9 bar) giving good early torque but there was a massive drop in torque at 5000 rpm that then leveled out before dying at 6500. This dip in the torque curve is almost certainly down to timing. Whether it is that the timing hadn't readvanced yet after the reset or whether it the fuel still isn't good enough to get optimum ignition advance I don't know. However, I am now very sure if I could run the car constantly on good fuel, the full 340 hp and 320 lb/ft would be easily available.

I personally thought your torque curve looked really impressive, especially beside the Sti's and even the P1. Insofar as it is possible to tell from the curve, I'd say it's a bit of an animal on the road.

I know it is very frustrating spending money and not getting the results (it happened to me before) but as Andy says, if you want roller results, you have to map on the rollers. If you did, with your set up, you'd easily see 300+ on torque and hp.

Don't know if the car would drive any better however.

There is an interesting post on the lancer register site where they put the FQ340 against the FQ400 on the road in a variety of tests. In almost all of the various head to heads that they conducted, the FQ340 was actually quicker than the 400 despite giving it a full 60 hp. The 340 pulled like the 330d you mentioned and got clear ahead well early on and the 400 was never able to close the gap.

Balls out however, the 400 was ultimately the quicker car (albeit not by much) as with its extra horses it could pull further in each gear and the initial gains of the 340 were eventually pulled in and surpassed.

I'd say if you put your machine alongside some of the similarly powered cars from Saturday, you might find a similar result.

Also, I'd say if you were to run some better fuel for a while, those losses might well disappear.

More importantly, how much will you lose when you move over to TT land?

Jesus, and I thought I was bad going for an Evo.

Type 25 man, has to be at that budget.

Seriously think about it, the last one is 350 and 355 lb/ft, the new one is 425 and 400. Ok it won't be quite that on our fuel, but oh my God, what a car.

In any event, you absolutely must have over 300 lb/ft it's essential, you won't last. No way.