Harrop/Eaton S/C

[Bles 32]

Have had the Harrop fitted now for a couple of day and find that it makes the car so much easier to drive. You don't need to rev the car to the red line in each gear as the torque is enough to get you where you want to be. This is probably the same with all the FI types but does make the car easier to drive in my opinion.

[Mark@Abbey M/S 235]

I have data from a full 2.3 Cosworth and the Harrop on the dyno at Abbey. The Harrop and Cosworth are very very close in regards IAT climb in a controlled dyno run.

 

Top 2 runs are from a Cosworth 2.3 full conversion the lower 2 runs from an Abbey Car (stock headers,2nd cat delete and exhaust system)

 

 

[Mark@Abbey M/S 235]

On 4/12/2016 at 10:48 AM, Ade said:

Fair enough. Thats probably about the same as my car with the cat back ~250WHP

How long were your sessions at Beford? 

Thing about the above run is if it was only after a few dyno pulls your IATs might be quite low. Increasing IATs lower knock limit so timing has to be adjusted and air density is lower so you lose some power.

Air density is 1.25kg/m3 @ 10C

Air density is 1.15kg/m3 @ 35C

That's an 8% drop in air density for a 25C rise. So 250Whp becomes 230WHP, but its worse in reality as you lose knock limit as well.  

The Harrop dyno run posted with ~250whp had 33C IATS.......

Edit* anyone that actually knows what they are talking about feel free is correct me. I am often wrong.

 

Ade,

 

I am afraid I don't agree with the above workings if so I would always get such a great difference in BHP/Torque on my Dynapack between winter and summer with the same car when in fact we don't maybe 5bhp but not 20/30 bhp I am afraid.

 

Same car same tune dyno plot below just different day , your see the temperatures int he dyno room during the dyno pulls.

 

 

[Ade 517]

 So how does the car makeup for the loss of air density?  Its oxygen that creates the power after all...

The thing about looking at IATs from Dyno pulls. Both system have about 5 liters of water so it will take time to heat that up due to the specific heat capacity of the water and you're blowing artificial air at the car on a stationary platform whereas in real life as you go faster you are pushing more air through the bumper. 

The real test will be a Snetterton this month, where Dan and I can properly compared, in the same conditions, what the steady state IATs will be on both kits.

It should also show us trap speed on the Vbox so dan will be able to see if he is slowing down on the straights due to loss of power.

The Harrop data I posted was from Harrop themselves from driving repeated laps on the track which is more real world data than dyno data I feel.

 

[S18 RSG 429]

I didn't think there was such thing as artificial air lol.

Just because the air is forced at the car via a fan doesn't make it artificial, it just makes the air speed artificial (when compared with actually driving through air). Air density is varied by temperature, not the method in which it's being fed to the car.

[Ade 517]

45 minutes ago, Mark@Abbey M/S said:

I have data from a full 2.3 Cosworth and the Harrop on the dyno at Abbey. The Harrop and Cosworth are very very close in regards IAT climb in a controlled dyno run.

 

Top 2 runs are from a Cosworth 2.3 full conversion the lower 2 runs from an Abbey Car (stock headers,2nd cat delete and exhaust system)

 

 

To be fair the Cosworth one climbed 25C - 30C thats 5C

The Harrop Climbed 33C-41C that 8C that 60% more!

Anyway as I say the real test will be this month

[Ade 517]

12 minutes ago, S18 RSG said:

I didn't think there was such thing as artificial air lol.

Just because the air is forced at the car via a fan doesn't make it artificial, it just makes the air speed artificial (when compared with actually driving through air). Air density is varied by temperature, not the method in which it's being fed to the car.

Come on, you know what I meant! Though we might need it when we all go to mars and they try to tax us for air. (I watch total recall last night)

[Mark@Abbey M/S 235]

So does the dyno lie then.........if your formula is right a car would have such a great change in BHP/Torque every car would be sold with a disclaimer saying this car only gives 200 bhp at 20 deb C ambient.......

So shall I throw my dyno away and every person that owns a dyno is wasting there time I don't think so.

My dyno plots showed the IAT c climb over a controlled dyno pull, which I feel is a good comparison.

Did you know too cold IAT can cause issues as well with the fuel not mixing with the air nicely.

 

Dan cars versus yours isn't a true test as Dan is running a very short final drive ratio so will be putting a huge amount of torque to the wheels over your car the rate of acceleration will be totally different.

I am going to get back to tuning now in my dyno....

 

 

[Ade 517]

5 minutes ago, Mark@Abbey M/S said:

So does the dyno lie then.........if your formula is right a car would have such a great change in BHP/Torque every car would be sold with a disclaimer saying this car only gives 200 bhp at 20 deb C ambient.......

So shall I throw my dyno away and every person that owns a dyno is wasting there time I don't think so.

My dyno plots showed the IAT c climb over a controlled dyno pull, which I feel is a good comparison.

Did you know too cold IAT can cause issues as well with the fuel not mixing with the air nicely.

 

Dan cars versus yours isn't a true test as Dan is running a very short final drive ratio so will be putting a huge amount of torque to the wheels over your car the rate of acceleration will be totally different.

I am going to get back to tuning now in my dyno....

 

 

 

I never said you should throw your dyno away! Just saying it not a true test of IATs.

 

 

 

 

 

 

 

[S18 RSG 429]

12 minutes ago, Ade said:

To be fair the Cosworth one climbed 25C - 30C thats 5C

The Harrop Climbed 33C-41C that 8C that 60% more!

Anyway as I say the real test will be this month

So the Cosworth climbed 20% of its starting ambient temperature with a beginning air density of 1.184kg/m3.

The Harrop climbed 24% of its starting ambient temperature with a beginning air density of 1.146kg/m3.

That's around a 4% difference in air density and a difference of around 4% increase in IAT. I'd say that balances it out.

[Ade 517]

 

Lets just see how the two cars compare at Snetterton!

[Rich 378]

Post-charger air temperatures don't affect the density of air, so you won't get power falloff due to lower intake air density. You might get power falloff due to knocking causing the ECU to back off from the high temperatures, but that is pretty much the only way you would.

The reasoning is that the air density that matters is the pre-charger density, which is only determined by atmospheric pressure and ambient temperature. Once the air has been pulled into the charger it's in a closed system and so the density cannot change via temperature changes. Increasing temperature in a fixed volume system (such as a car's intake manifold) will increase pressure rather than reducing density.

[Ade 517]

35 minutes ago, Rich said:

Post-charger air temperatures don't affect the density of air, so you won't get power falloff due to lower intake air density. You might get power falloff due to knocking causing the ECU to back off from the high temperatures, but that is pretty much the only way you would.

The reasoning is that the air density that matters is the pre-charger density, which is only determined by atmospheric pressure and ambient temperature. Once the air has been pulled into the charger it's in a closed system and so the density cannot change via temperature changes. Increasing temperature in a fixed volume system (such as a car's intake manifold) will increase pressure rather than reducing density.

That makes sense to me and lines up with what Mark was saying about not seeing massive differences between winter and summer. Happy to admit when a theory is wrong because that all it is. It would rely on the screw sealing 100% though.

Having said that, what Lauren describes as power drop off with high IATs is a real thing. Plenty of info on the ft86club about the positive displacement supercharged cars getting hot and many claiming that they are unable to pull away from N/A GT86/FRS/BRZ when they've been lapping a while. 

 

[nerdstrike 186]

Having higher pressure behind the charger screw will also increase load on the charger itself, but I don't think that would be a very large drain on available power compared with the existing load.

[DanJ 374]

On 4/12/2016 at 9:42 AM, Ade said:

Nope. Plenty of datalogs stateside from all three kits.

Harrop have just released some data. They were running ~70C IAT in 28C ambient.

Edlebrock was running 56C in 21C ambient

Mine was about 26C is 10C ambient at Bedford.

 

Without access to the standard I can't explain the thermodynamic theory behind it, but dyno correction factors calculated according to SAE Standard J1349 work out to ~ -2% engine power for every +10deg.C IAT, this Cf decreases as IAT increases. This standard is for NA engines and is used by OEMs to normalise measured power outputs for changes in atmospheric pressure and temperature. 

The Harrop data above is from their track car that's running the HKS Stroker Kit, ACE Manifold, HKS Exhaust, E85 and a 65mm pulley (vs 95mm standard) its putting out 380HP at the wheels with the SC running at a pressure ratio of 2.2, so the 70deg.C IAT comparison isn't really valid.

 

[DanJ 374]

As promised, logged data from Snetterton yesterday, Harrop SC with 4.67 FD and stock exhaust. The majority of the peak IATs are off-throttle when bypassing.

 

[rob275 1817]

@DanJ Just for clarification... I'm right in thinking you have the Harrop in here and @Ade has the Cosworth? Temps seem fine here. What were the ambient temperatures at Snetterton?

[Rich 378]

Ambient was around 10C.

[DanJ 374]

@rob275 that's right, I've edited the original post so all the info is together.

[Ade 517]

Cool. I'll get something up very soon.

P.s. looks like you were short shifting 

and possibly had extra "load" in the passenger seat 

 

 

 

 

[Ade 517]

1 hour ago, rob275 said:

@DanJ Just for clarification... I'm right in thinking you have the Harrop in here and @Ade has the Cosworth? Temps seem fine here. What were the ambient temperatures at Snetterton?

Yeah the reason the Harrop stuff I posted was higher IATs was because the Harrop car is running the 60ish mm pulley which is good for about 320WHP on normal fuel (also had hks stroker kit). Epic fail on my part to spot that as I thought it was taken from their car running the stock pulley. 

So Dans car is representative of what you should expect. Obviously driving style, skill, speed and other things come into it, but you are looking at roughly 25-30C over ambient steady state. 

[DanJ 374]

11 minutes ago, Ade said:

Cool. I'll get something up very soon.

P.s. looks like you were short shifting 

and possibly had extra "load" in the passenger seat 

 

Yep, was shifting up early to help with oil temps, need to sort that cooler out!

It was the run with you as a passenger, you're the independent witness 

[Ade 517]

Just now, DanJ said:

Yep, was shifting up early to help with oil temps, need to sort that cooler out!

It was the run with you as a passenger, you're the independent witness 

One things for sure the car was being pushed pretty hard 

[Kodename47 446]

How did you guys find the difference in FDs?

[Mark@Abbey M/S 235]

@DanJ good infomation , will be good to see @Ade data as well from yesterday.

Can we also see graphs with RPM and car speed with IAT if possible please.

Thanks