GR Yaris Intercooler performance and lag

Onehp

Onehp

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At times we've been discussing IC performance and more specifically how the IC size influences lag.

A good IC manufacturer will publish test data on cooling effect and pressure drop. But usually lag isn't mentioned. So this thread is about discussing all aspects of IC performance and also lag.
 
So this quoted post linking to an article trying to dismiss any relevance of a few litres IC volume it states:

"In REALITY, airflow out the turbo travels at f***ing HUNDREDS of miles per hour, and airflow in to the engine consists of HUNDREDS of litres per f***ing second"

So I went away and made some calculations. Anybody have better ones, let me know....

A GR Yaris at lowish revs where you can actually want response, say 3000rpm for easy calculation, that gives 50revs/second. At 0,8l/rev displacement, the volume flow in the IC is 40 litre per second. On a 53mm pipe that is 40 mph. Hundreds being at least 200, he is off by factor 5. Perhaps volume flow is correct on a 8l Viper engine that has been turbocharged, but that wasn't the subject of his article either... So writing f*cking and capitalising doesn't make you right...

So I went about trying to make a reasonable assumption how much lag we are talking about between IC systems, assuming both can cool to similar IAT and one is big pipes and core with low pressure drop, one optimised for low volume. Comparing for the same boost, the smaller one will make ballpark 10hp less, the larger one can probably take more boost but now we are comparing all else the same and usually people will prefer the bigger one as bigger is better, right?

Assuming volume on one IC system is 8l and another is 16l with pipes 1,4x the diameter and a bigger core. If we're boosting 1,5 bar, these pipes will need to be filled with another 12 respectively 24l of pre-turbo atmospheric air, or 12l difference. This difference is filled by the transient between steady state pre-turbo flow of 40lps (no boost) and 100lps (=1,5 bar boost @40lps post-turbo) = on average 70lps air.

12l/70lps=0,17s.

This is 0,17s difference assuming both IC's are sufficient to cool to similar IATs.
However it isn't that simple, this is on top of the time it takes the turbo to up its pre-turbo atmospheric flow from 40lps to 100lps, and boost builds as a result of boost, that is, the turbo system is a reinforcing system: bit more boost means more combustion, more revs, which gives in turn gives more boost again, more combustion, more revs more boost etc. So the real difference will probably be larger as the larger volume to fill puts a delay on building boost. How much, don't know depends on so many things. On the other hand the larger system has a lower pressure drop but we talking no more than ballpark 0,05bar difference at these flows so not hugely significant on 1,5bar (3%), while the lag is ballpark 30% difference.
Let's settle for 0,2s difference in lag ballpark.

Will you notice it?
If you're driving a very twisty road with limited view with full throttle applications of 1-2s at a time, a difference of ~0,2s in boost build-up will definitely make a big difference.

If driving on track and you already know whats coming and you just apply throttle ~0,2s earlier and keep it WOT for 20s after that, you'll definitely have more use of the added power (potential) a bigger IC system gives.
 
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So how long are the boost pipes? 1m of 60mm internal diameter equals 3 litre, 43mm (stock?) equals 1,5 litre.
Internal core volume isnt as much as the space the core occupies which are usually the published numbers, maybe 25-30%?, pure guess.
End tanks can also differ quite some in volume, if roomy can be similar volume to the core itself.

Here it would be best to just measure to get data. Fill IC system with water, measure volume. At this point all is educated guess/ballpark from measurements avaialble.

Lag can be mesured with proper high frequency logging equipment. But in the end the subjective impression is what matters.
 
Full height ICs are coming, great for Big Power
lamspeedracing.com

Hypertune Bolt On Intercooler - Toyota GR Yaris 2020+ and 2023+ GR Cor

Details: Hypertune products are known to be manufactured right here in Australia powering some of the fastest time attack and drag cars world wide with their world class design, fabrication and light weight tube in fin intercooler cores. Witnessing the potential of the Toyota GR Yaris in the...
lamspeedracing.com lamspeedracing.com

Do88 also had one coming
 
Onehp said:
Full height ICs are coming, great for Big Power
lamspeedracing.com

Hypertune Bolt On Intercooler - Toyota GR Yaris 2020+ and 2023+ GR Cor

Details: Hypertune products are known to be manufactured right here in Australia powering some of the fastest time attack and drag cars world wide with their world class design, fabrication and light weight tube in fin intercooler cores. Witnessing the potential of the Toyota GR Yaris in the...
lamspeedracing.com lamspeedracing.com

Do88 also had one coming
Click to expand...

These make a lot of sense. Big area without big volume
 
DeanoC said:
These make a lot of sense. Big area without big volume
Click to expand...
Yep thats the big plus.

As it then covers the coolant radiator it needs to be a bit more open to let enough cool air through. And risk for more heat soak from said radiator if stationary. Its all about balancing properties...
 
Just my two cents. Lag is the time between throttle change and engine response. Main factor is the length of the pipes and intercooler (volume of air) between throttle body and cylinder. If you can "shorten" this length the engine will respond more lively. That's the reason some manufacturers nowadays use water-cooled intercoolers placed as close as possible to the inlet manifold.

Bye for now Fred
 
Where does the power come from changing the ic? Its mainly the lower intake air temperature, right? Nothing else?

And whats the intake air temp with stock ic and aftermarket?

Just to understand whats the benefit of a bigger cooler. For me it sounds like you are at about 50 °C with stock, 35 with ic swap / stock pipes and 30 with ic / pipes swap. So the addidional benefit from bigger pipes is not that much hp but gives much more lag. Correct?
Whats the total hp gain of an ic? Is it about 10 or 20 hp?

If you change the turbo you might have a totally different scene, but can we focus on stock turbo and max. 400 hp. To discuss drivability / lag for a 600 hp Yaris is kind of useless I thing ;)
 
Tralien said:
Where does the power come from changing the ic? Its mainly the lower intake air temperature, right? Nothing else?

And whats the intake air temp with stock ic and aftermarket?

Just to understand whats the benefit of a bigger cooler. For me it sounds like you are at about 50 °C with stock, 35 with ic swap / stock pipes and 30 with ic / pipes swap. So the addidional benefit from bigger pipes is not that much hp but gives much more lag. Correct?
Whats the total hp gain of an ic? Is it about 10 or 20 hp?

If you change the turbo you might have a totally different scene, but can we focus on stock turbo and max. 400 hp. To discuss drivability / lag for a 600 hp Yaris is kind of useless I thing ;)
Click to expand...

It's really about not losing power over adding power. It often supports turbo mods that increase boost and heat.

The car is noticeably slower with 40-50 intake temps over 10-20 degrees
 
Most people think that a bigger IC adds power.
Which is basically never happening unless in very extreme circumstances.

A bigger IC’s job is to make sure you can use your power longer.

If you look at most of the currently available IC, they‘re mostly very tall with a big surface and therefor more suited for Drag Racing and Dyno Runs where a smaller but thicker IC suffers from heat soaking.

But on a racetrack, the taller ones will compromise the airflow to the radiator.
So they worsen the ability of your radiator to cool the water and at the end (if you didn‘t add an oil cooler in the first place) will increase your oil temps.
 
For me it is mostly about I hate the softer throttle pedal feel as temps in the engine go up. I want the car to perform as consistent as possible year round, and with as little lag as possible. Not about numbers on the street (don't track) but about driving enjoyment.

Bigger boost pipes reduce pressure drop over the IC system, meaning the turbo needs to work less to get the same manifold pressure. But we're talking about approx 0,05bar difference between aftermarket IC's, this can render about 5hp, I rather have even small gains in added response...
 
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Fair enough, I have edited my original reply. My fault, I should have found an article with some actual testing rather than an opinion.

On topic, I might be able to test this at work, albeit on low revving diesels rather than petrols, With our setup, it shouldn't be too hard to double the intake pipe length and/or diameter in places. I'll find out. I could also vary the exhaust back pressure to test the effect on the hot side.
 
I'm sure it won't be bad, just mentioning this aspect as it is often forgotten and, at least for me, also an important part of driving enjoyment.
 
And I'm sure it won't be as catastrophic as it is sometimes portrayed as bad.

Since the car often feels so castrated in the summer, I hope to be able to counteract this a bit.
 
Yeah, in almost all cases, an upgraded IC is always better than without in summer...
 
So there are 2 points that add power? Better cooling / lower temps AND less pressure drop / more boost at engine?
Ic is for cooling and little pressure and pipes for pressure?

Ive never owned a turbo before and I am very new to turbo engines :(
Thats why I will start with exhaust and ecu (if available)....but the 3rd thing then is ic I think if you wanna do more. And I want to fully understand what I am doing. I want to choose the right parts for my special case
 
For big power it is 'simple', upgrade IC needed to keep performance, choose your level.

@Tralien
For response, NA engine is a awd rally car is not done so we always work with turbo... ALS is a bit much too, what gives super response to competition cars. (Edited) What is left for even better response is trying to improve the charge and, related, inlet temps and backpressure. More here.
 
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Not directly on the subject but nice video on the intercooler performance gains in dyno. There is not actually that many comparison videos of stock vs. aftermarket intercooler.
 
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