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Old 06-18-2013, 02:47 PM   #12
1st Gear Newbie
Join Date: Apr 2012
Location: sarnia
Posts: 20
This dyno is not a heartbreaker. See above posts.

Won't let me update the op for some reason. So here are the graphs with afr's:

Note: afr sniffer was not in the exhaust for the stock tune run.

Sal at Evolve made some comments (he is referring to the supercharged tune):

Originally Posted by evolve_auto View Post
Please ignore the stoichometric running at low rpm. This is where the DME goes from closed to open loop and the AFR catches up. If we measure AFR closer to the headers it looks very different.
The AFR also goes momentarily rich but again, this is just to do with catching up of the integrators.
High rpm we run around 12.8 AFR and because we are running such low ignition targets (16-18 degrees Maximum) the exhaust gas temperatures are nice and low. There is no need to run much more rich than this.

I am sure someone will say it's all too lean :-) Before you say this... remember, under 5000rpm these kits make next to no boost at all. The cylinder filling is not great, EGT's are very low and the engine just doesn't benefit from using any more fuel. All that happens is that the fuel flies out of the exhaust and actually bogs the car down.

The tuning is based on getting the correct fuel, nice low ignition timing and altering the valve overlap so that the 'boost' is used properly.
Originally Posted by evolve_auto View Post
This is also a chance to say a few things which are important:

1) I did ask for this dyno session to be ideally not on the forums. The kit manufacturers do not like this and I do like to respect their feelings. No one has ever retuned any of our hardware better than us so I have not yet experienced what it feels like.

2) People think we get more power by tuning more aggressively. We do not. The power comes from not running them overly rich and then the valve overlap changes. Ignition timing is extremely low. More power is available than this also but at the expense of the possibility of knock as you venture into the low to mid 20's ignition targets. It just doesn't take into account what happens when things start getting too hot and another sensor is not working.
What we are essentially doing is improving efficiency. It's a little like taking a stock S54 and removing timing. Power drops by say 15rwhp. It's a little too far out on the calibration side!!
bluewater87 is offline   Reply With Quote