His engineering assumptions in the video are wrong. He takes no account of engine size. He’s averaging 3 different engine power increases and boost levels and coming up with an averaged bhp per psi figure of 6bhp/psi which he assumes applies to all engine sizes. He then uses this to calculate a requirement of 33psi of boost to give 200bhp increase on the 4.3 litre engine. Total nonsense, it’s like saying if you boosted a 3bhp 50cc lawn mower engine with an 8 psi supercharger you’d also get a 48bhp increase. Assuming all things being equal power gains will be proportional to displacement not independent as he assumes.

The enemy of supercharging a high compression ratio engine is the air temperature at the top of the compression stroke, which if too high causes pre-ignition. Reducing compression ratio is one way of reducing temperature and so is water injection and inter-cooling. With no cooling a CR reduction from 11.3 to 8.3 would maintain the uncharged peak air temperature just prior to ignition with 8psi of boost. Also cooling the intake air back down to ambient temperature would do the same thing. The advantage with cooling rather than CR reduction is that it doesn’t loose cylinder pressure so gives more power for the same boost level.

Theoretically if boost doubles the ambient pressure of the intake air, it will double the power output of the engine. So 14.5psi boost theortically doubles the power output on an engine with non-reduced CR. 8psi boost on the 380bhp 4.3 engine should then theoretically give a 209bhp increase so above what GMR are claiming.

There are many other details that will have to be engineered correctly to have a reliable and robust supercharger installation but I see nothing impossible about their power claims.

 

Any updates? Have any Supercharger units shipped? I am ready to order today, but weary of throwing that much cash at something yet to be delivered.

Also sent an email direct to GMR and it was returned stating their mailbox was full? Hope they are still up and running.

 

Got a response from GMR today. They have shipped 4 units total including the one Rich already installed. They are hoping to ship more in May, though not sure of how many. I am getting with @Redpants to see how long the waiting list is. I think I will pull the trigger today.

I just put the Velocity AP tune and pullies on the wife's Jaguar F-type, so it's now around 650hp. I can't have her car being that much faster than the Aston. With the GMR kit and less weight we should be much closer in speed.

 

Sorry about that!