Dynos

Noel · March 24, 2007

hope Lee doesn't mind me using his chart but i'm curious as to why the graphs don't cross....?

or maybe it's some kind of end combo result sheet

MacRS200 · March 24, 2007

Because the power is in horse power and the torque is in Newton Metres :winky:

Edit - Perhaps I should explain a bit, the same amount of torque in NM is a bigger number than lb/f so the torque curve stays above the power one.

Edited March 24, 2007 by MacRS200

Noel · March 24, 2007

Ah.... ok, that makes more sense

Bazza · March 24, 2007

Here is a pic of my latest dyno graph.

Thankyou :)

first link confirms what I say on which my comments are based_-_-_ namely if bhp & torque dont cross at 5252 rpm the dyno reading is inaccurate. your graph doesnt. could be that the reported figures are higher in fact...........

perhaps i need to borrow your glasses dave B)

sure looks to be crossing at around 5250 rpm to me

Again I put this down to jealousy.

damn right .....I certainly am :D

Dave-Ellen · March 24, 2007

I'd suggest spec savers whose prices are reasonable :winky:

Mr Morse · March 24, 2007

There's no way those curves cross @ 5250

More like 5150

Adie · March 24, 2007

I'd suggest spec savers whose prices are reasonable :winky:

There's no way those curves cross @ 5250
More like 5150

The dyno kings hey? You two must have so much knowledge on this matter.. Please share it with us.

So far NONE of my questions have been answered or Neils for that matter. Or Barries.

The only person so far who knows what he is on about is Neil. You two obviously have your own opinion and agenda but are not prepared to state your workings out.. Just what you've concocted together.

Got something to say then back it up with facts. Not your opinions, which seem to be a minority..

Why dont you both post up your own car projects? As you both seem to be such experts. But again you talk a good story but can't or wont back it up.

Noel · March 24, 2007

it's not my intention to add fuel to the fire but in the interest of sticking to the facts .....

section divided into four equal parts....

Mr Morse · March 24, 2007

I'd suggest spec savers whose prices are reasonable :winky:

There's no way those curves cross @ 5250
More like 5150

The dyno kings hey? You two must have so much knowledge on this matter.. Please share it with us.

So far NONE of my questions have been answered or Neils for that matter. Or Barries.

The only person so far who knows what he is on about is Neil. You two obviously have your own opinion and agenda but are not prepared to state your workings out.. Just what you've concocted together.

Got something to say then back it up with facts. Not your opinions, which seem to be a minority..

Why dont you both post up your own car projects? As you both seem to be such experts. But again you talk a good story but can't or wont back it up.

Look at the graphical evidence.....

Dave-Ellen · March 25, 2007

it's not my intention to add fuel to the fire but in the interest of sticking to the facts .....

section divided into four equal parts....

nuff said

marcus · March 25, 2007

First / Only 1G-FE IS 200 over 400 bhp in UK

Ad i think you will be the only one to take the 1G-FE to over 400bhp as the rest of us are not that mad :P :winky: can not help but think of what it has cost you to get it there this is why i went with the V8 as with this i will see 500+ RWHP to start with just by adding a Turbo.........

any how have fun in it mate, as your is quick for now! :winky: :D

Monster-Mat · March 25, 2007

it's not my intention to add fuel to the fire but in the interest of sticking to the facts .....

section divided into four equal parts....

nuff said

exactly , just under 5250......

an error of 50-70rpm, is neither here of there, other factors can alter the change over point in a minor way...

why argue, make discussion over 50-70rpm..

at least we are seeing Dyno print outs.

this topic has nothing to do with THAT specific print out.....its is to do with Dyno's in general, got any of your print outs dave for comparison, i really want to see this exact cross over point.

EDIT:

having actually now read the whole topic, you will notice on a previous page that Mac has pointed out, ALREADY, as to why the lines will not always cross

MacRS200 · March 25, 2007

nuff said

Well not really Dave.

Interesting discrepancy you found there, so there is a 50 - 100 rpm difference in the "cross over point" on Adie's plot, lets split the difference and call it 75rpm.

Now as we all want a bit more info on dyno readings and how to interpret them, would that make any difference to the overall power plot? If so would it be more or less and by how much would the max power change

Adie · March 26, 2007

Look at the graphical evidence.....

Yes.. and your point is

nuff said

Obviously not as you've STILL not explained what it means etc. Neil has asked a few questions too, still unaswered as has Mat.

Ad i think you will be the only one to take the 1G-FE to over 400bhp as the rest of us are not that mad :P :winky: can not help but think of what it has cost you to get it there this is why i went with the V8 as with this i will see 500+ RWHP to start with just by adding a Turbo.........
any how have fun in it mate, as your is quick for now! :winky: :D

Mad... maybe, but somebody has to do it at sometime, why not me. Cost is a problem but if it was done correctly in the first place then cost would be alot lower. It doesn't pay to cut corners. Good luck with your project and I hope you get the power you're after. But make sure you post up the dyno sheets :winky:

On another side note..

On saying what you want to say face to face............i've no problem with that. Tried it today.........bloke had nothing to say

Again not true. You offered to buy me a tea as soon as I got there. Which I declined as I went to que and book for the 1/4 mile strip. I never saw you again after that only when you once drove past me ;)

(I've posted this part in public not in a PM so those that read your forum can also read the truth ;) )

Anyway back on topic.. thanks to Neil, Noel and Mat for the input on the subject of dynos, very interesting and informative posts. Now can we please have some answers to the questions?

tdiplc · March 26, 2007

I offered to educate Dave on this very issue a week or so ago on this thread, but he declined.

The formula that Dave dug up is only valid when applying Imperial measurements, ie foot pounds and Imperial horse power, therefore any data that is measured in anything that is not Imperial units cannot use this formula.

The power shown in the graph that Adie has displayed is measured in Metric Horespower, not Imperial Horsepower, therefore the power and torque curve will not cross at 5252 rpm

Well done to Mac for identifying the correct data, and for asking completely legitimate questions.

I wonder if we'll get an admission or an apology for being incorrect and for using inappropriate and offensive language?

Adie · March 26, 2007

nuff said

Well not really Dave.

Interesting discrepancy you found there, so there is a 50 - 100 rpm difference in the "cross over point" on Adie's plot, lets split the difference and call it 75rpm.

Now as we all want a bit more info on dyno readings and how to interpret them, would that make any difference to the overall power plot? If so would it be more or less and by how much would the max power change

Neil it looks like you'll have to answer these for us please mate :)

aido · March 26, 2007

The power shown in the graph that Adie has displayed is measured in Metric Horespower, not Imperial Horsepower, therefore the power and torque curve will not cross at 5252 rpm

Now I'm totally confused - what's the difference between metric horsepower and imperial horsepower?

Does it just mean that on the graph torque is worked out as either lb/ft vs NM depending on whether it's metric or imperial, or does it mean that there are two different types of horsepower ratings?

Gord · March 26, 2007

The power shown in the graph that Adie has displayed is measured in Metric Horespower, not Imperial Horsepower, therefore the power and torque curve will not cross at 5252 rpm

Now I'm totally confused - what's the difference between metric horsepower and imperial horsepower?

Does it just mean that on the graph torque is worked out as either lb/ft vs NM depending on whether it's metric or imperial, or does it mean that there are two different types of horsepower ratings?

Aido, take the Astra VXR says its 240psi (most car makers now use this, psi) but bhp is less than 240 :duh: i do have the conversion somewhere

aido · March 26, 2007

Oh right so that's what it means, yeah seen that referred to before, cheers pal :)

chrisis200 · March 26, 2007

Sure cost is a factor as others may want to follow & it's good to educate people an help them work out costs... but at the same time only Adie knows how much is to much for him to spend on this project.. As he's said it's sadly not gone well so far therefore costing alot more, I'm glad he's sticking with it & sure this car will be awesome if competed to it's potential. It's one I'd certainly have to go to the shop to see :D

It's a shame dyno's cant be more simple for noobs like me to read lol...

Could I ask how much they cost to have one done? I'd like to see if I still have as much BHP as it should have as when it was first made :( after watchin top gear that time with the old super cars they lost loads of horses lol...

MacRS200 · March 26, 2007

nuff said

Well not really Dave.

Interesting discrepancy you found there, so there is a 50 - 100 rpm difference in the "cross over point" on Adie's plot, lets split the difference and call it 75rpm.

Now as we all want a bit more info on dyno readings and how to interpret them, would that make any difference to the overall power plot? If so would it be more or less and by how much would the max power change

Neil it looks like you'll have to answer these for us please mate :)

One Imperial HP = 1.01 Metric HP so difference is 1%, roughly the difference between the RPM of the "crossing point" on your plot and 5250, 75 RPM being 1.4% of 5250 RPM.

So Adie the bad news is that your max RWHP is down about 3.5 bhp to a lowly 346.5 bhp I am sure that you will be most disappointed

ps - if anyone really wants the answers to the other questions I posted please ask :D

Edited March 26, 2007 by MacRS200

Adie · March 26, 2007

Thanks Neil. Feel free to answer the others mate so we can all understand the subject a bit more :)

MacRS200 · March 26, 2007

Q1 - What power is an engine producing if the torque is 170NM @ 3000 rpm.

A1 in Kilowatts - (2 x Pi x Torque x RPM)/(60x1000) = 53.4KW the divide by 60 x 1000 converts from minutes to seconds and watts to kilowatts.

A1 in BHP - 1Nm = 0.735 lb/f so 170Nm = 125 lb/f use the formula (Torque x RPM)/5252 and you get 72bhp.

Q2 - One Imperial Horse Power is 33,000 Lbf/Min, so to cancel the 2 x Pi from the top line you divide 33,000 by 2 x Pi that equals 5252.11312203................ (for as long as you want). No time conversion is required as the definition of HP is per minute and the RPM uses the same time scale.

Adie · March 27, 2007

Nice one :D

tdiplc · March 27, 2007

Q1 - What power is an engine producing if the torque is 170NM @ 3000 rpm.
A1 in Kilowatts - (2 x Pi x Torque x RPM)/(60x1000) = 53.4KW the divide by 60 x 1000 converts from minutes to seconds and watts to kilowatts.

A1 in BHP - 1Nm = 0.735 lb/f so 170Nm = 125 lb/f use the formula (Torque x RPM)/5252 and you get 72bhp.

Q2 - One Imperial Horse Power is 33,000 Lbf/Min, so to cancel the 2 x Pi from the top line you divide 33,000 by 2 x Pi that equals 5252.11312203................ (for as long as you want). No time conversion is required as the definition of HP is per minute and the RPM uses the same time scale.

Excellent and accurate answers - well done to you Neil :D

I would also mention that Imperial Horse Power has not really been used as an industry standard unit of measurement for quite a while. Metric Horse Power is now the order of the day :)