VQ35 on the Engine Dyno

Several months ago when we had the VQ on the engine dyno at Cosworth, I snapped a couple of pics. Since I never got to work on engine dynos very much in the past, I thought it was way cool to see a street car engine that we [the mostly unibody car crowd] commonly build/tune/whatever on a professional grade engine dyno. The ease of working on the engine is nice: there are no cut arms, burnt hands, busted knuckles, and emanating under hood heat blasting you in the face like on a chassis dyno. The amount of data we can collect is ridiculous too.

In the US, we do not have transient dynos. I think Cosworth has 7 transient dynos in the UK, but that is the SUPER big dollar equipment for F1, LeMans, OE development, etc. In the US, we have two computer controlled German water brake dynos capable of handling 1,000bhp each. One of the features that set the Cosworth dyno cells apart are the climate controlled air inlet and cells. If I want to tune the entire intake air temperature correction range, we can just set the A/C to match the break points on the correction maps. If I want to tune the entire barometric pressure correction range, we can do that too and match the break points on the maps. If I want to tune the entire coolant correction range, we can do that too since coolant temperatures are controlled by the dyno’s control computer. It goes on and on. We can control barometric pressure, humidity, air temperature, oil temperature, cooling system pressure, and many other things. All of this is excellent for consistency too. Test results between different days are remarkably consistent and we are able to test engines for longer durations of time. On a chassis dyno, you cannot control the environment so your results are subject to fate and we all know fate isn’t always kind. Plus a loading chassis dyno is only as good as the car’s cooling system and the dyno’s fans. A chassis dyno definitely has it’s role, but man I dig the engine dynos at Cosworth. The dyno cells were originally put in place for the race engine programs, but the performance parts side of the business gets to benefit by using them too.

Aside from the Cosworth EC Pro ECU (prototype: it looks like we’re not going to release a VQ ECU) logging many channels of data, the dyno also has it’s own Pi Sigma logging system. That rectangular box behind the engine is 18 pressure transducers for collecting data. In front of the engine (not in picture) is another panel for 24 temperature probes, 12 exhaust gas temperature probes, and numerous auxiliary inputs. This was the Castrol Top Shop Challenge engine.

On the roof is a giant boiler to control humidity, water tank, and air plenum that is climate controlled for the engine’s air intake. We can take extremely accurate measurements of air flow and brake specific fuel consumption which is very helpful in engine development or in my case, product development.

This dynosheet is NOT the Castrol Top Shop engine. This is a dynosheet of a bone stock 287hp 3.5L VQ35DE bottom end with stock pistons, rods, crank, etc. The heads were Cosworth CNC ported big valve heads, with the new Cosworth ZK2 camshafts, and Cosworth Intake Manifold. We used a pair of shorty DC headers to simulate real world testing. Peak power/torque was 359.1bhp/284 ft-lbs. with the Cosworth induction parts and 289.5bhp/253.6 lb-ft. with the stock induction parts. That’s a 70bhp gain just by a healthy increase in airflow. With all that extra meat in the power curve, you know this engine would be fun to drive!

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