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Example

Car A - V8 N/A. IT of say... 40 degrees according to DD Testing rules

Car B - Turbo/Intercooler 6. IT of also 40 degrees according to DD Testing rules

Which car gets the more unrealistic reading? Car B.

Why? Lets see if people can workout why.

  • Like 1

And we have a winner... never takes long for someone with half an idea :(

40 degrees for the V8, the turbo car is reading 40degrees.

However then the I/C is doing its work, so the figure is incorrectly having adjustments on it for the turbo car.

Hence i dont agree with DD methodology. It works for NA no problem, not turbos

From what I was told, a shootout run should have the inlet temp sensor placed inside the inlet tract just before the throttle body i.e after any intercoolers etc but this is obviously going to be more time consuming on a dyno day for example and never is adhered to.

Depending on where you put the inlet temp sensor, when i tune my car we leave the sensor hanging in ambient temp, not in front of the pod filter as if the motor is sucking hot air i would like to know about it on the dyno so i can rectify the problem. This was my intercooler is never going to cool below ambient, so there would be no problems.

Ok, I have spoken to a few people about this, including a Dyno Dynamics Shootout operator (not the one who tested the car). I have trouble believing that a stock R33 with only turbo-back exhaust and pod filter can make 178rwkw, but noone seems to be able to give me a straight answer.

I can't post my dyno sheet so I guess, it doesn't really matter. I would like to try and understand how a dyno works, so I can then work out how accurate power figures are when you see dyno print outs.

Edited by Quinny
And we have a winner... never takes long for someone with half an idea :P

40 degrees for the V8, the turbo car is reading 40degrees.

However then the I/C is doing its work, so the figure is incorrectly having adjustments on it for the turbo car.

Hence i dont agree with DD methodology. It works for NA no problem, not turbos

Thus the reason for;

Shootout Mode 6

Shootout Mode 6F

Shootout Mode 8

Shootout Mode 8F

There are different correction tables/values for forced induction cars.

Thought this was fairly apparent.

Adrian

Come on, your not meant to post that :rofl:

How does a dyno know the efficiency of a intercooler setup of any given vehicle? Whats it based upon?

I'd be extremely interested to know how they have a correction table that can take into account a heatsoaked system, or adversly an extremely efficient one.

with the tyre thing...the blokes at mercury told us to put some skinny ass tyres on there to get a higher hp reading, we had 255 semi slicks at the time.

Edited by r33_racer
Come on, your not meant to post that :rofl:

How does a dyno know the efficiency of a intercooler setup of any given vehicle? Whats it based upon?

I'd be extremely interested to know how they have a correction table that can take into account a heatsoaked system, or adversly an extremely efficient one.

I fail to see how a heat-soaked system (or otherwise) will affect the power being produced at the rear wheels any differently to how that same heat-soaked system would at the track?!?

Shootout mode was designed to make COMPARISONS more accurate.

So the question of whether intercooler efficiency can be measured on a chassis dyno is moot. It is a more accurate representation of the RELATIVE performance of different types of vehicles on a chassis dyno.

Nothing more, nothing less.

And if anyone has a problem with DD dynos or chassis dynos in general, remember the lowly video cassette tape. Beta is said to be a technically superior system but the popular standard won out in the end. Is it a good thing? Is it a bad thing?

Who cares. It's the standard that people use.

Deal with it.

Are we talking about the track? I dont recall that being so.

Its not a moot point at all. Its extremely relevant.

If you have corrections being applied, based one some "software" thinking there is much lower IT temp than is actually being supplied based on some corrections table within the software itself... then how it is gone to be anywhere near accurate? because it isnt.

Thought i'd save you the heartache of answering that one cause i already know the answer.

Setting up a performance car is all about the package.

Inlet air temp compensation should not be taking in to account.

Ambient yes..

Why should the pod bloke receive a slightly inflated figure when at the strip the conditions are not 'equaled' via an IT temp sensor.

Tyre sizes might give you a bigger hp reading or not

its EXACTLY THE SAME AT THE TRACK

the smaller the tyre the more revs you have in the top end

the bigger the less

Thats when you change gear ratios ETC

and do you know gear ratios also make a difference on a dyno As do on the track

Most DYNO QUEEN cars Run a 3.11 or so gear ratio to help load the dyno more giving a Incorrect reading.

99% of our skylines run a 4.11 4.36 gear and same as most toranas and v8`s

The Shootout mode was designed For COMPARSION from dyno to dyno as mentioned early.

In order for you to be happy then

RUN A AIR TEMP SENSOR JUST AFTER YOUR THROTTLE BODY and get the temperature there and match it on the air temp sensor on the dyno.

What about cars with nitrous and cooler fuel

do you wanna take this into account as well

Nitrous i think is around -50 or so when entered into the manifold and heats up as it goes it

what do you do there

......................................................................

Anyways like i said

TUNING TOOL

Are we talking about the track? I dont recall that being so.

Its not a moot point at all. Its extremely relevant.

If you have corrections being applied, based one some "software" thinking there is much lower IT temp than is actually being supplied based on some corrections table within the software itself... then how it is gone to be anywhere near accurate? because it isnt.

Thought i'd save you the heartache of answering that one cause i already know the answer.

That photo SUITs ya

RUN A AIR TEMP SENSOR JUST AFTER YOUR THROTTLE BODY and get the temperature there and match it on the air temp sensor on the dyno.

Which I think is a load of crap... Its incorrect for one car that has been setup poorly to have its dyno reading inflated due to greater IAT's. It should be based on amb that places a small correction on the run; close the bonnet do the power run and thats it.

I'm not saying that towards you, its towards dyno dynamics. As what are you to dyno dynamics apart from using the product? sfa. :(

However, can you see my point of view?

I'm very aware that a dyno is a tuning tool and power figures should be taken with a pinch of salt since right back when I had my first dyno run on an old analogue needle swinging pice of crap.. (~9yrs ago)

My view is that if a car is making up close to 200rwkw well its getting up there and most definitely not making a stock 125rwkw.

+- ~20-30rwkw, outside of that and I tend to start thinking some one is playing funny buggers.

MR331307, please don't get personal towards other forum members. Functional discussions get us all places, dysfunctional gets us no where.

He is just trying to have a dig at me with something he thinks he knows heaps about... but cant even address the simple issues surrounding it all.

But if its a tuning tool, i dont see why it requires such indepth explainations such as post #1... :P

All's fair in love and war.

And its me in my avatar :)

Come over for a DECA weekend, we'll show ya how to drink some booze :(

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