New Rolling Road Results

[Cyclone1]

On the back of the "new" method of recording rolling road bhp and torque, I decided to get my car testing using the same "new" method, my results are as follows:

18/02/2006 406bhp 382lb/ft (3rd Gear)
18/02/2006 408bhp 383lb/ft (3rd Gear)
18/02/2006 410bhp 383lb/ft (3rd Gear)

Last night we decided to run the car as per the cars at Surrey Rolling Road, this is in Shoot 8 mode and in 3rd gear and then in 4th gear which is what is being banded about as being the best method to use. My car was set-up the same as per the 18/02/2006, the only difference being that my car now had a full tank of BP Ultimate as opposed to 1/4 tank of Optimax, my results were as follows:

27/02/2006 403.9bhp 383lb/ft (3rd gear)
27/02/2006 404.3bhp 382lb/ft (3rd gear)
27/02/2006 406.5bhp 385lb/ft (3rd Gear)
27/02/2006 417.5bhp 400lb/ft (4th gear)

As you can see from the above the first three runs from last night were very consistent in 3rd gear and also pretty close to what we achieved on the 18/02/2006, on switching the run into 4th gear the figures noticeably rise the bhp by 3.5% and the torque by 5%. I could have ran my car again in 4th but it was getting late so the figures may have been slightly higher.

From this I have to ask the question of which figures do I belive are correct and for me at the moment it is still 3rd gear, if it's 4th (same as the mapped cars at Surrey RR on Saturday) then that means my car has 417.5bhp and 400lb/ft torque.

The graph below shows my first three runs in 3rd gear with the 4th gear run overlayed, I have also included the at the wheels figures (hope this doesn't cause more debate).



>> Edited by Cyclone1 on Tuesday 28th February 08:51

[cuneus]

Game set and match

[nelly1]

Don't you reckon this 3rd gear / 4th gear thing has got a bit out of hand?

I think you can say without doubt that your car has a reliable 400bhp and nigh on 400lb/ft!
That's still mighty impressive!

3% is hardly a big deal, and for future RR days, so long as all the cars are run the same way, you should still have some meaningful comparisons.

Just my 2p.

Neill

[Mr Freefall]

Cyclone1 said:

On the back of the "new" method of recording rolling road bhp and torque, I decided to get my car testing using the same "new" method, my results are as follows: 18/02/2006 406bhp 382lb/ft (3rd Gear) 18/02/2006 408bhp 383lb/ft (3rd Gear) 18/02/2006 410bhp 383lb/ft (3rd Gear) Last night we decided to run the car as per the cars at Surrey Rolling Road, this is in Shoot 8 mode and in 3rd gear and then in 4th gear which is what is being banded about as being the best method to use. My car was set-up the same as per the 18/02/2006, the only difference being that my car now had a full tank of BP Ultimate as opposed to 1/4 tank of Optimax, my results were as follows: 27/02/2006 403.9bhp 383lb/ft (3rd gear) 27/02/2006 404.3bhp 382lb/ft (3rd gear) 27/02/2006 406.5bhp 385lb/ft (3rd Gear) 27/02/2006 417.5bhp 400lb/ft (4th gear)

Didnt a Red Rose hit 434 on the day, which is around 17BHP more than yours. I thought that Red Rose cars were making around 20BHP more, which would be about right for all the arguments that have beed banded about.

Mr F

[Mr Freefall]

What were the figures at the Wheels Jules?

Mr F

[kojak]

Fantastic results Julian. Great results.

[Cyclone1]

nelly1 said:

3% is hardly a big deal, and for future RR days, so long as all the cars are run the same way, you should still have some meaningful comparisons. Just my 2p. Neill

3-4% makes a difference of between 12-18bhp, which when a car has been tuned can mean that the gains look a lot larger than what they actually are. If you can get away with it then fine, but it prevents the chance of comparing tuning from car to car, unless of course they are all at the same rollers on the same day.

My point from above is what power torque does my car have???

406-410bhp and 382-383lb/ft torque (3rd gear) or
417.5bhp and 400lb/ft torque (4th gear).

My car only has an Emerald remap, short induction hoses and some minor airbox mods, so I would guess that the first figures are more appropriate, this would mean that the 4th gear runs are not as accurate???

Jules.

>> Edited by Cyclone1 on Tuesday 28th February 11:21

[Steve_T]

You gained 13hp over previous 3rd gear tests and nickccc gained a similar amount comparing his 3rd and 4th gear tests, could this not simply be explained by differing gear box losses?

Edit: Thinking about this further - how are the losses calculated on a DD dyno? If they're a fixed percentage and this percentage is not altered between doing a 3rd and 4th gear run, but the actual gearbox losses do change because you get direct drive in 4th, could you not end up over-reading a little?

Just a thought,

Steve.


>> Edited by Steve_T on Tuesday 28th February 12:14

[trackcar]

Steve_T said:

You gained 13hp over previous 3rd gear tests and nickccc gained a similar amount comparing his 3rd and 4th gear tests, could this not simply be explained by differing gear box losses?

nope cos it's a calculated back flyhweel figure, you tell the dyno what gear you're in so it should work it out correctly and the model should account for the differing gerbox loss and extra roller speed and tyre resistance etc etc otherwise what's the point of having the model? we might as well all use coastdown (which works very well at Nobles I have to say). what we're proving is that when you run the DD dyno *inside it's roller computer model* it's amongst the most repeatable and dare I say it accurate roller system in the world! Run it outside that model and it isn't, which is entirely understandable.

The *engine* doesn't gain 13/16bhp by running in 4th gear does it?. 400lbs torque from a 2 valve n/a engine is just a joke. 360 odd lbs is what you'd expect for a good 2 valver, 380lbs is exceptional and bordering on the unbelievable (though we know the DD slightly exagerrates the midrange on it's runs on these cars at least)

[Mr Freefall]

trackcar said:

Steve_T said: You gained 13hp over previous 3rd gear tests and nickccc gained a similar amount comparing his 3rd and 4th gear tests, could this not simply be explained by differing gear box losses? nope cos it's a calculated back flyhweel figure, you tell the dyno what gear you're in so it should work it out correctly and the model should account for the differing gerbox loss and extra roller speed and tyre resistance etc etc otherwise what's the point of having the model? we might as well all use coastdown (which works very well at Nobles I have to say). what we're proving is that when you run the DD dyno *inside it's roller computer model* it's amongst the most repeatable and dare I say it accurate roller system in the world! Run it outside that model and it isn't, which is entirely understandable. The *engine* doesn't gain 13/16bhp by running in 4th gear does it?. 400lbs torque from a 2 valve n/a engine is just a joke. 360 odd lbs is what you'd expect for a good 2 valver, 380lbs is exceptional and bordering on the unbelievable (though we know the DD slightly exagerrates the midrange on it's runs on these cars at least)

SO WHAT ARE THE FIGURES AT THE WHEELS THEN JOO. I would say in the region of about 335 BHP...

This should be a good measure no?

Mr F

[mongoose]

Cyclone1 said:

3-4% makes a difference of between 12-18bhp, which when a car has been tuned can mean that the gains look a lot larger than what they actually are. If you can get away with it then fine, but it prevents the chance of comparing tuning from car to car, unless of course they are all at the same rollers on the same day. My point from above is what power torque does my car have??? 406-410bhp and 382-383lb/ft torque (3rd gear) or 417.5bhp and 400lb/ft torque (4th gear). Jules.

Firstly i'd just like to say it was nice to meet you on Saturday(all too briefly),and see that lovely Cerb of yours-just fabulous
Onto the subject.The most accurate figure must surely be the lower one.I really cannot understand why any rolling road operator would want to ignore the manufacturers recommended set up,other than to deliberately inflate figures for the 'feel good factor' in an attempt to gain business.Joo goes to great lengths to be as accurate as possible,and i for one feel he deserves great respect for that.I will always prefer the rolling roads that give the lower numbers,they have nothing to gain from this,apart from said respect.
My Griff made 311bhp on Friday at Trackcar,and i was well chuffed because i know the figures weren't inflated,if i had got my figures at Surrey or Austec,i'd now be sat here wondering what it really made-defeats the object a bit to me!

[trackcar]

They're on the graph, but that's complicated by the way the DD arrives at those figures I think ..

in 3rd the hp at the wheels shouuld be raised by the gearing ratio minus the friction losses, but the DD doesn't recreate that .. something to do with the tractive effort which I've never had adequately explained to me, possibly because only the dyno designer truly understands the principle.

For instance the graphs above show 4th producing more hp at the wheels, this is obviously not true in real life as that would mean the car would accelerate faster in 4th gear than 3rd, i think we can all see that is bollox otherwise why change down to 3rd to overtake and why set off in 1st gear? use 4th and enjoy fastest acceleration from 15mph to 160 mph .. no need for any other gear! utter rubbish of course.

it's a peculiarity of the DD that i still don't understand as I said because no-one I speak to can explain it in terms i can comprehend! lmao. the hp at the wheels in 3rd shoud be massively more than the hp at the wheels in 4th because of the torque multiplication of the gearbox (that's it's job!) times the revs used ... maybe I'm just thick.

If anyone can explain that point I'd be most impressed.

[Steve_T]

trackcar said:

... the hp at the wheels in 3rd shoud be massively more than the hp at the wheels in 4th because of the torque multiplication of the gearbox (that's it's job!) times the revs used ...

I don't agree about your point regarding 3rd gear hp, torque and horsepower can't be interchanged as you imply. (horse) Power is force x velocity. The torque at the wheels and therefore rollers would be increased by the gearing in exactly the same way that the rate of rotation of the rollers (and therefore velocity) would be reduced, when comparing third and forth gear. If there were no differences in losses between the roller speeds of third and forth (obviously there are in real life), then the power would remain the same. The difference in acceleration is simply the difference in torque at the wheels and therefore the force accelerating the car, due to gearing.

Steve.

>> Edited by Steve_T on Tuesday 28th February 13:03

>> Edited by Steve_T on Tuesday 28th February 13:05

[mad mark]

Has anyone tried this 4th v 3rd thing on a big powered Jap car such as a Supra? To see if there is a difference in these cars aswell.

Failing that, is anyone going to volunteer to take out their engine and have it run up on an engine dyno and then again on the RR in 4th and 3rd? (it's a bit extreme, but it should settle it once and for all)

[Cyclone1]

mad mark said:

Has anyone tried this 4th v 3rd thing on a big powered Jap car such as a Supra? To see if there is a difference in these cars aswell. Failing that, is anyone going to volunteer to take out their engine and have it run up on an engine dyno and then again on the RR in 4th and 3rd? (it's a bit extreme, but it should settle it once and for all)

If you read the above then you should understand that there is still a discrepency between running in 3rd and 4th gear. Your car actually proves the point perfectly:

You think you have a car that is 400+bhp when in fact it probably produces no more than 380bhp at best, as proved at SRR where it produced 377bhp? Now that the "goal posts" have been moved you want to believe the higher figures....that's your choice.

My car reads anywhere from 404-410bhp and 382lb/ft in 3rd and 417.5bhp and 400lb/ft in 4th, therefore I know that the 4th gear readings are a joke, either that or I have a super torquey Cerb....not.

Like I've said, if you are happy with your figures then great. But when it comes to comparing what mods produce what gains then the comparisons become unequal and hard to quantify, if this doesn't bother you then fine, but plenty of owners out there want to modify their cars and want to honestly know what extra bhp they are going to get.....it would just be nice once and for all if we could have a level playing field. But as someone has instigated a change of tactics on Saturday then this is not the case. Stand up and explain yourself or sit down and continue blinding the customers, can't say much fairer than that.....and yes it is my opinion. My money spent on my car pays for the wages of these outfits, so I have a right to know what I am paying for.....do people not agree?

Jules.

[trackcar]

Steve_T said:

I don't agree about your point regarding 3rd gear hp, torque and horsepower can't be interchanged as you imply.

yes they can, they're mathematically linked .. Hp is torque times revs devided by 5252. you *cannot* separate the two things. If you wind the torque up through the gearbox you *must* incerase the hp at those revs, you *cannot* do anything but as the two are linked by maths .. unless you have some strange calculator that defies the laws of maths and physics. The hp of the engine doesn't change, but the hp at the wheels does. this is one reason why wheel figures are misleading despite what many people will have you believe. Wheel figures are only comparable for the same type of car with the same gearing.

[Steve_T]

trackcar said:

Steve_T said: I don't agree about your point regarding 3rd gear hp, torque and horsepower can't be interchanged as you imply. yes they can, they're mathematically linked .. Hp is torque times revs devided by 5252. you *cannot* separate the two things. If you wind the torque up through the gearbox you *must* incerase the hp at those revs, you *cannot* do anything but as the two are linked by maths .. unless you have some strange calculator that defies the laws of maths and physics. The hp of the engine doesn't change, but the hp at the wheels does. this is one reason why wheel figures are misleading despite what many people will have you believe. Wheel figures are only comparable for the same type of car with the same gearing.

I'll say it again you cannot interchange torque and horsepower. Torque is a rotational force, power is a measure of the rate at which work is done, i.e. force x distance/time. Here the force is rotational and the distance is the angle. To increase the torque, through gearing, you are reducing the angle through which that force is applied. Work done - force x distance is constant - otherwise you defy the laws of physics.

[jeremyc]

daggart said:

I take it if i now say that my car gave 443.4bhp and 422lbs of torque its just going to wind some people up?.

Depends which gear it was in at the time.

[methodwares]

Steve_T said:

trackcar said: Steve_T said: I don't agree about your point regarding 3rd gear hp, torque and horsepower can't be interchanged as you imply. yes they can, they're mathematically linked .. Hp is torque times revs devided by 5252. you *cannot* separate the two things. If you wind the torque up through the gearbox you *must* incerase the hp at those revs, you *cannot* do anything but as the two are linked by maths .. unless you have some strange calculator that defies the laws of maths and physics. The hp of the engine doesn't change, but the hp at the wheels does. this is one reason why wheel figures are misleading despite what many people will have you believe. Wheel figures are only comparable for the same type of car with the same gearing. I'll say it again you cannot interchange torque and horsepower. Torque is a rotational force, power is a measure of the rate at which work is done, i.e. force x distance/time. Here the force is rotational and the distance is the angle. To increase the torque, through gearing, you are reducing the angle through which that force is applied. Work done - force x distance is constant - otherwise you defy the laws of physics.

wikipedia

they cannot be interchanged as they totally different dimensionally, but the can easily be converted back and forth (with the aid of a calculator)

[Steve_T]

methodwares said:

Steve_T said: trackcar said: Steve_T said: I don't agree about your point regarding 3rd gear hp, torque and horsepower can't be interchanged as you imply. yes they can, they're mathematically linked .. Hp is torque times revs devided by 5252. you *cannot* separate the two things. If you wind the torque up through the gearbox you *must* incerase the hp at those revs, you *cannot* do anything but as the two are linked by maths .. unless you have some strange calculator that defies the laws of maths and physics. The hp of the engine doesn't change, but the hp at the wheels does. this is one reason why wheel figures are misleading despite what many people will have you believe. Wheel figures are only comparable for the same type of car with the same gearing. I'll say it again you cannot interchange torque and horsepower. Torque is a rotational force, power is a measure of the rate at which work is done, i.e. force x distance/time. Here the force is rotational and the distance is the angle. To increase the torque, through gearing, you are reducing the angle through which that force is applied. Work done - force x distance is constant - otherwise you defy the laws of physics. wikipedia they cannot be interchanged as they totally different dimensionally, but the can easily be converted back and forth (with the aid of a calculator)

I quite agree, but the flawed interchange of the terms torque and horsepower is the posts below is not helping the debate, just further muddying the waters.

>> Edited by Steve_T on Tuesday 28th February 15:24