Minor update... Bill is hopefully going to weld up the manifold if he finds a spare 5 mins this week (ta mate
) and I have been looking at the scaling for the S4 MAF tube too...
Plotting the various sets of MLHFM data you can see the differences between the two main sensors in use (040 for narrow band ME7 and 049 for wideband ME7.5... the RS4 has a different sensor again)... Early S4's used a Bosch sensor where later ones use a Hitachi... I used an A-Box file to get the Bosch data from which uses the 040 sensor...
First, a comparison of RS4, S4 (Bosch 040), S3 (APY and AMK) and an A3 (AUM)...
Next a direct comparison of S3 sensors... APY (040) maxes at 276gs while AMK/BAM (049) maxes at 292.58gs... same size tube...
Thanks to Kev for helping with working a few things out... I had already worked out that the percentage increase in surface area between the S3 MAF (69mm ID) and the S4 MAF (76mm ID) was just over 20% but didn't think it would be as simple as just 'increasing' the figures this way but to cut a long story short it kinda was... Kev did the calcs and plotted against my existing data (I work with data all day long and simply couldn't be *****...) and bingo.. a plausible set of data to use for the MAF scaling...
On the 040 sensor the S4 MAF maxes out at 335gs/418bhp... theoretically if I have got the maths right then the S4 tube with my 049 sensor in it will be good for 351gs/438hp which is more than enough for my setup...
This should work well with the 90mm TIP I have planned... to give you an idea of the increase in size I am currently using 76mm OD tube (smaller than Bills K04 TIP!!!)... here is a 76mm OD pipe next to the 90mm OD pipe I am going to use...
Hoping to get the manifold mostly done this weekend and the revised charge pipework cut ready for welding...
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