Mark@Abbey M/S

that's normal with the early cars rear cambers , go with Super Pro rear camber arm/toe arm kit works a treat. Shame the people aligning the car didnt sort the rear toe's out properly , the Thrust angle will not help needs to be zero thrust

Yes I am pretty happy it will pass easily now with the larger capacity HFC

Yes I am pretty happy it will pass easily now with the larger capacity HFC

Sorry our demo car is still running the awesome Harrop

200 cell Ceramic brick, better quality cat than the original Cobra HFC and a large capacity brick as well so it will hold more heat. 
  ACE header bolted back on our Demo car with the new Cobra HFC no additional tuning done , just drove up and carried out a normal MOT emission test.  
 

 
We think we can get a small extra resonator in the blue ringed position but our car with the stock exhaust system is only slight louder than a stock car at idle and general driving , not pulled any full throttle pulls yet as want to check the map on our in house dyno.   Should have some news back from Cobra very soon I hope      

been fitted,fitment is good , passed MOT on our demo car just need to try it on a NA car will happen shortly. Hopefully in the next week. thanks

I did wake me up.....

BMW dynoplot (hub bhp figures)

Under bonnet as good as the Harrop install on the FA20 I feel.

There a few other kits on the horizon from Harrop.
 
 
 
 
 

We have a very strong feeling it's the, likely cheaply made flex joints used on the longer runners.
Another member mentioned that he had the same noise I'm experiencing on a previous car, which was fixed by the flex joints being replaced. I also found out that my fitter didn't leak test the flex joints, only the flanges.
Gonna see if I can get the exhaust place that made my catback to either cut them out and replace them, or try and seal them up properly. 
That is, unless you have any suggestions and/or solutions?

Hi Mark could be interested after the testing is complete.
Rod

Same here....

Think you know I want one but just double checking  

Put me down on that list as well please Mark.
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Sorry been so busy;
  Cobra have delivered the prototype large capacity HFC for testing;     around 35% larger capacity so should flow real well , hold the the heat longer so better for MOT passes and be very reasonable cost wise;   Hope to have some news very soon.

Sorry been so busy;
  Cobra have delivered the prototype large capacity HFC for testing;     around 35% larger capacity so should flow real well , hold the the heat longer so better for MOT passes and be very reasonable cost wise;   Hope to have some news very soon.

One things for sure the car was being pushed pretty hard 

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

Ambient was around 10C.

@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?

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.
 

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.
 

All the SC system we have fitted use a by pass valve so even at high rpm (spinning the charger faster) at small throttle openings the by pass opens and the air bypasses the SC unit. So no boost is used when cruising.
You do need to drive a SC car thou. Your welcome to have a drive in our demo car.
 

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....
 
 

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.

I'd be interested to see the Cosworth instructions, the Harrop ones are vague in places, I've taken lots of pics of key stages to fill in the gaps for others.
The intercooler plumbing may cause a rethink for the oil cooler ducting, time will tell tomorrow!
Hope BCS deliver for you soon.