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Old 02-04-2017, 05:38 PM
Richard L Richard L is offline
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Join Date: Oct 2003
Location: England
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Default Re: WMI tuning and results Part 2

Quote:
Originally Posted by theboostshack View Post
G’day guy,

I’ve been posting on this forum for a few years now but this is my first post since changing user name. Just wanted to shed some more light on the results from most recent experimentation with the water meth injection system fitted to the boost shack 1600. The previous results can been seen here http://www.aquamist.co.uk/forum2/vbu...ead.php?t=2987
In this instalment, the aim was to optimise the tune in the lower RPM range and increase the total power output by increasing the water meth flow to around 50% of total fuel flow. This equated to roughly 1250cc/min. The system was set up to use a total of 4 jets, 3 in the charge pipe post intercooler and 1 pre turbo.
Tuning saw us achieve some great gains in the lower and mid range RPM, as you can see from the before and after dyno pictures below. But with the water meth activated, we soon realized that this configuration was not yielding the results we were after, with a 16kw decrease over our last peak numbers.
At this point, we took a set back and sat down with the Unigroup Engineering crew to investigate the possible causes of the drop in power and a way ahead. In the end it came down to the fact the we were injecting too much water meth in a localised area, as we had over 1100cc/min being injected at one area post intercooler. This caused the air to reached and exceeded 100% saturation point, meaning the amount of air entering the engine could no longer suspend the liquid being injected in an atomised form. This causes overcooling of the combustion process due to poor atomisation, leading to a loss in power, which is exactly what we were experiencing.
It was decided that we would remove one of the three charge pipe jets which would reduce the post intercooler injection to around 800cc/min. This resulted in an 11kw in in power and a much nicer power curve right through the rev range. That said, we were still 5kw off our previous peak of 336kw. We decided to leave it there for now, as we will be making some changes in the near future, which we will expand on shortly.
Apologises for the late post.

Have your consider reducing the spark gap just in case the ignition system is stressed and not allowing sparks to fly? 0.4mm is not out of the normal on some very powerful engine I came across in the past.
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