Intercooler Efficiency

[Guest dturne81]

i take it you guys are quoting the dyno sheet figures posted by Gamer.

 

Ambiant temperature is the temperature of the dyno room air.

Intake temperature is the air being drawn in through the air filter before being compressed. This air is being blown into the engine bay by a large fan.

The inlet charge temperature of the engine is not required for power corrections.

 

Hope that clears it up for you guys a little. The charge temperatures are well above ambient.

 

Cheers

 

Dan

[imi]

Bob thats my thinking too..............

- maybe there is a hidden freezer somewhere

[bondango]

Im not a dyno operator but my understanding is this.

 

Ambient temps are the surrounding environment temperatures i.e. the Outside Temperature, these readings are also used in some cases with humidity/altitude etc

Inlet temps must be recorded just before the throttle body, i.e. engine intake. This is also the position were most aftermarket ECU's or piggy backs which use a MAP configuration i.e. Manifold pressure and Intake pressure also take there reading from - Gamers is an example of this. HKS VPC uses the same setup with IAT mounted pre TB.

 

So Basically a normal aspirated car, and a turbo charged car must have the temps taken pre throttle body. But in the case of a Turbo charged/super charged car, the Dyno operator would need to mount the Probe in the inlet before the TB after the Intercooler to get the correct reading on the Dyno.

 

So, unless they do this, the dyno reading are not 100% accurrate, or am i missing the point and rambling?

[Terminator]

Like you not a dyno operator, however I would have thought it would be the temperature of the air entering the TB that would be of most significance.

[dandan]

Im not a dyno operator but my understanding is this.

 

Ambient temps are the surrounding environment temperatures i.e. the Outside Temperature, these readings are also used in some cases with humidity/altitude etc

Inlet temps must be recorded just before the throttle body, i.e. engine intake. This is also the position were most aftermarket ECU's or piggy backs which use a MAP configuration i.e. Manifold pressure and Intake pressure also take there reading from - Gamers is an example of this. HKS VPC uses the same setup with IAT mounted pre TB.

 

So Basically a normal aspirated car, and a turbo charged car must have the temps taken pre throttle body. But in the case of a Turbo charged/super charged car, the Dyno operator would need to mount the Probe in the inlet before the TB after the Intercooler to get the correct reading on the Dyno.

 

So, unless they do this, the dyno reading are not 100% accurrate, or am i missing the point and rambling?

 

Surely mounting the temperature sensor (for the dyno correction) just before the throttle body rather than at the air filter is a bad idea - hence why it's generally not done.

 

If that's done then two identical cars except for their intercooler effiiciencies would be corrected to approx the same power/torque.

 

The one with the crap intercooling would read a much higher temperature thus be subject to more correction for temperature. The car with adequate intercooling will have cooler charge temps and not be subject to the same amount of correction.

 

In the real world the car with the better intercooling will make more torque (assuming all other factors are equal).

 

As Dan said, no IAT sensor is needed for dyno correction - only the ambient air temperature - this allows some hope of dyno comparison on different days along with baro correction.

 

The charge temp rise, relative to ambient, of the air that's now passing the throttle body is down to car design and installation (filter position and ducting, compressor efficiency, intercooler efficiency etc).

 

The ECU will always want charge temps for its own correction (in the plenum or pre throttle plate) but that's different again to the simple dyno ambient temp adjustment.

 

Does that make sense?

[foodfreak]

I often keep an eye in inlets temps through my R-vit, it measures through the temperature sensor in the throttle body.

In the summer on very hot days when ambient temps have been 28-30C, at a steady 70-80 mph inlet temps have been around 18-22c.

in very slow traffic it can get as high as 48c, but as soon as there is a reasonable flow at 30-40mph you can see the temps visibly dropping very quickly to 22-28c

John

[gregsupra4]

*POSTED UNDER GREGS ID*

Dturne81 wrote;

 

 

 

It was I that mapped Gamers car on the dyno. I am slightly offended that someone would think that the results are being manipulated to give "Customer pleasing results"......

 

With the way that correction factors work if I had set a lower intake temperature then the correction factor would actually REDUCE the engine corrected power figure. (Cooler air boosts performance correction factor allows for that)

 

When dynoing cars the inlet charge temperature is not taken into account (Although it is an input to the ECU). Only the ambient air temperature, intake air (Air going into the filter) baro pressure and vapour point are taken to give correction.

 

Just as a bit of background info. I have been running engines on dynos (Engine test bench, rolling road & Hub dynos) for 10 years. This includes F1 engines, BTCC, GT-LM, WRC, Automotive projects, Jaguar, Aston Martin, Ford, Land Rover, Bentley, Rolls Royce and even some aircraft developments. I have commisioned dyno installations for automotive manufacturers that have cost in excess of $2M so you could say I've a done a dyno session or 2 in my time.

 

As I said I am a little offended by a couple of the remarks in this thread but I do understand that there are some dyno operators and dyno figures out there that are set-up to give "customer pleasing results" My dyno is not one of these.

 

As a last thought I would also like to say that BHP is irrelevent.... Its torque at the wheels/time that is important to me as that is what actually accelerates a car down the road.

 

Regards

 

Dan T

[Wez]

I hope none of my comments caused offence as that was not the intention, we are as a group just trying gain further understanding on such matters.

 

[Ian C]

Aha as we have an expert in dynoing to hand, What about the 21% transmission losses that got plugged in? For a manual car? The dyno guy I used put in about 7%. That'd give Joe about 525bhp at the crank, a 100bhp drop from how it actually read.

 

-Ian

[Terminator]

I was not intending to offend either.I know nothing of dyno therory so bow to Dans superior knowledge. Any thing I previously post in this thread was in the context of the title, of the thread "intercooler efficiency", a topic that interests me a great deal. We all know that heat is the torque robbing factor in forced induction cars. A few laps of any track with an after market under bonnet filter so demonstrates that with out ambient air ducting the car suffers badly coming out of slow corners.

 

It would be good to get some facts on the BBS about IC design and efficiency. ie.Simple things like washing out the is IC can make a difference, as with age oil film build up acts as an insulator, thus decreasing it inefficiency.

Adding a simple water mist spray in front of the intercooler at to fire at a predetermined boost level.

Pipe work designs that hinder or improve IC efficiency.

IC construction.

 

An IC is just a heat exchanger, anything that lowers the approach figure is advantageous to our cars.

[Wez]

I think intercooler sprays sound like a good idea, but how much would you need to become really effective.

[TLicense]

As a bogey figure, I've been told that if you take the vehicle's forward velocity, the airflow through the exchanger is only about 20 of this.

 

Unfortunately I don't think it's as simple as applying any kind of rule of thumb, as it has a lot to do with pressure gradients across the intercooler which is largely determined by the flow velocity into the intercooler ducting and also the geometry behind the intercooler.

 

I'll have a chat with a couple of aerodynamicists and see what they think as we do a VERY similar thing each year when designing rad ducts....

[bondango]

Think most people were trying to get a handle on what temps are actually measured on a dyno hence my post, and wernt trying to say that results were fudged - The only Fudging of results that can be done from what i know are through the drivetrain losses that the operator uses.

the easiest most effective ways for change cooling would be Water/meth injection and IC spraying as previously noted. Though ive seen elaborate setups using Chargecoolers combined with an IC, after all, an IC needs airflow through it before it can start cooling.

[Guest Pizza-Tosser]

What does the dyno do with the figures it gets for intake temp etc, are they used in any of the calculations?

 

Dynopacks add horse power based on the intake probe temp so make sure it's not hanging near the exhaust or reading some silly temp due to thermistor issues.

 

So always get a temp plot !

[Digsy]

Unfortunately I don't think it's as simple as applying any kind of rule of thumb, as it has a lot to do with pressure gradients across the intercooler which is largely determined by the flow velocity into the intercooler ducting and also the geometry behind the intercooler.

 

I'll have a chat with a couple of aerodynamicists and see what they think as we do a VERY similar thing each year when designing rad ducts....

 

That would be interesting to find out more about.

 

My 20% figure came from one of our vehicle cooling engineers, and is primarily aimed at the likely flow through a radiator and trying to take into account tha tfact that it will more than likely have an AC condensor and other gubbins in front of it, plus an engine bay behind. I guess you F1 types have a bit more room in your sidepods

 

We tend to use a lot of rule of thumb fugures like this for initial sizing because we never have the budget to do CFD or any other kind of meaniingful simulation first.

[Guest dejacky]

how about using an intercooler misting kit on a side mount intercooler? would spraying a very fine mist in front of the sidemount intercooler even cause residual water to hit the tire and cause slippage? or would it be so small it would be irrelevant in terms of traction?

[Wez]

how about using an intercooler misting kit on a side mount intercooler? would spraying a very fine mist in front of the sidemount intercooler even cause residual water to hit the tire and cause slippage? or would it be so small it would be irrelevant in terms of traction?

 

This is a very old thread, I would also assume that the water sprayed onto the IC would evaporate as it does its job.

[monsween]

Get ready for the sarcy comments.............