Rolling road

[dreadnought110]

:shock:  Ah well shoved the old gal on the rolling road today and got the bhp and torque figures? Don't no if i should be happy or depressed? :?

[madmatt]

I don't think you should be depressed with ya torque fiqures, BHP umm well you need a standard 300TDI to go against.

[Porny]

Lets see the figures then...

But don't think too much into it, rolling roads are not always the most accurate things  

[Xtremeteam]

got 120 BHP & 180 Ibft when i had mine on the rollers last  8)

[dreadnought110]

got 120 BHP & 180 Ibft when i had mine on the rollers last  8)

Well tell me how this work's then mine was 105 bhp 230lb/ft?? In the 1994 brochure i have for defender the 300 tdi is quoted at 111bhp and 195lb/ft

[Magnum335]

What are those allisport stickers doing on pray i ask?

[dreadnought110]

:D Yes she runs 300tdi with allisport intercooler and JF tweaking.. still weird figures though??I tweaked it while on the rollers though and actually found that theres a point that to much fueling reduces your BHP..

[defenderdan]

Did you have a great big fan blowing through your intercooler? If there's no air flow through it then it doesn't matter how big your intercooler is.

[dreadnought110]

:D Yeah it had a great fan at the front and before each run a quick blast of something on the intercooler to almost freeze it!! :D

[Magnum335]

The torque figures seem vaguely correct.
What was the state of your air filter?
I see why you might be depressed....

[dreadnought110]

Tryed it with and without the airfilter didn't make any difference it does go better now though the torque is well impressive!! :lol:

[Xtremeteam]

got 120 BHP & 180 Ibft when i had mine on the rollers last  8)

Well tell me how this work's then mine was 105 bhp 230lb/ft?? In the 1994 brochure i have for defender the 300 tdi is quoted at 111bhp and 195lb/ft

thats running a statndard intercooler & staright through zaust with just the pump opened up (diaphram turned) nothing else

[paul_humphreys]

:D Yeah it had a great fan at the front and before each run a quick blast of something on the intercooler to almost freeze it!! :D

Would have been CO2 from a fire extinguisher.

Paul

[Magnum335]

got 120 BHP & 180 Ibft when i had mine on the rollers last  8)

Well tell me how this work's then mine was 105 bhp 230lb/ft?? In the 1994 brochure i have for defender the 300 tdi is quoted at 111bhp and 195lb/ft

thats running a statndard intercooler & staright through zaust with just the pump opened up (diaphram turned) nothing else

I think dreadnaught was getting wondering about the lower torque figure....

[dreadnought110]

:) Thinking about it the fan on the rolling road could have been to low driving to work this morning she is a lot smoother and pull's better mind you it's wet and foggy the best driving condition? :D

[rollazuki]

actually found that theres a point that to much fueling reduces your BHP..

And also leads to cracked pistons!!!!!!!!!!  Be carefull.

[bezzabsa]

Love to get my bike on that
:D:D:D
full chat - without the speeding tickets :D

[rollazuki]

trust me, owt on a dyno aint fun, cos you can hear all the rattles and vibrations that you normally leave behind when travelling at speed. If it doesnt sound broken on the road, it will on a dyno. :lol:

[dew1911]

Don't forget that engines seem to "loose" BHP as they get older, A car which left the factory with 200bhp can sometimes only regester around 180 not 10 years later, how old is the 300 and what kind of miles did it have on when fitted?

[Xtremeteam]

Don't forget that engines seem to "loose" BHP as they get older, A car which left the factory with 200bhp can sometimes only regester around 180 not 10 years later, how old is the 300 and what kind of miles did it have on when fitted?

yeh but both mine & dreadnoughts have both been "tuned" slightly his more than mine as im still on a standard intercooler,also mine was of an unknown milage or history & is a wee sweety,milages doesnt mean much on a TDi aswell aslong as its been reasonable well looked aftermknow some TD5s that couldnt pull you out of bed & some TDIs with over 290K that go like stink standard

[dew1911]

Tuning doesn't remove the loss of power though. I admit it's funny for a tuned one to produce less BHP than standard (unless you work for Alpina) but it may not be as bad as first thought.

[dreadnought110]

:shock: It just makes me wonder how can the bhp be lower than standard but the torque's up by nearly 30lb/ft ? i think i agree that with other people i have spoken to that  the fan was to low resulting in the intercooler not working at full efficency yes we cooled it just before w e ran it up again but that doesn't make that much difference because the air coming in was so dam hot it warmed it up very quick and you can different result's from one rolling road to another!! :roll:

[dew1911]

It could be a case of the engine was set up to produce a higher torque figure at the expense of BHP. I have no idea how you would do that but it's a possibility.

[dreadnought110]

:D All i know is after fettling it on the rolling road it shift's a lot better and i know that A. max torque's 2000 rpm B. max bhp is 3000rpm so no point in revving over 3000rpm and do all gear changes about 1800 to 2500 rpm and she accelarate's fast and sweet!! 8)

[Porny]

I would never believe a rolling road....

Ideal as a comparison (i.e two cars, one after the other) but alot of rolling roads work the figures out in different ways.... and not all of them are that accurate!!!  :roll:  A useful tuning tool though.

When we put Allisports old TMC racer on the rolling road, the figure was lower than expected... but when you actually went in it... blinkin'eck was it quick!!!  :shock:


Ian

[dreadnought110]

:? My point exactly!!

[90DV]

How does a rolling road work out the figures anyway?? Because don't they work out the fly wheel figures, if so how is this done???

[Porny]

How does a rolling road work out the figures anyway?? Because don't they work out the fly wheel figures, if so how is this done???

That's the problem.. a lot of Dyno's use different calculations!!!

Lets see...

Chav A - Has a nova.

Takes it to rolling road place X.  They do a bit of tuning, and give power outputs.  He makes 100bhp at the wheels... Chav is chuffed.  Brags to his mates.
Some of his mates reckon they use a better rolling road, so off he goes to rolling road place Y.  They put his nova on the rollers and his modified 1.2 shopping trolley makes 33bhp.

Chav A now thinks that the Rolling Road Y is naff and they don't know what they are doing... carries on boasting about figures from Rolling road place X.

The difference... the formula used by place X is very unrealistic - but has the effect of making them sound very good.

Place Y, uses a more accurate method - but some customers are not happy with the results!


And this does go on!!!


Have a read here: http://www.pumaracing.co.uk/power3.htm for how the calculations are made.


Ian

[ian_s]

hmmms, i'm confused now,

reading the stuff on that link, he says that the transmission losses are a percentage of your flywheel BHP. but a more powerful engine will lose a smaller percentage.

what i am getting at is: would the transmission losses be the same in bhp lost for my old 2.25 diesel and my 200tdi?

ian

[dew1911]

That´s a brainwave I had earlier - The figures you are reading off the Brochure are more than likley Engine figures, where as the rolling road could be giving you the power leaving the wheels.