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Discussion in 'VAG-COM & Diagnostics' started by DPJ, Feb 7, 2006.
It sucks very freely, Martyn. (The cork etc has been tidied up since)
smaller intake tho marts, lcr run a larger intake/maf
dave, replied to your pm
MAF alone can be misleading Martyn, you need to correlate with req. v act. boost. Remember that standard RS4 I told you about? Gave a peak MAF number suggesting ~420bhp but when looking at boost log, you could see requested was at atmospheric but delivered had spiked slightly as the driver lifted off, giving the 'false' MAF reading.
Doh! Forgot about the different MAF size...
Glenn...I remember mate!
I thought g/s was the weight of air passing through the MAF tube per second.
So the area of the tube section shouldn't be relevant....... The MAFs should be calibrated to take area into account...
But what do I know......
As another note...I thought 170g/s was roughly the max a K03s could flow.....?
your right, its the scaling of the MAFs thats different depending on engine afaik
ZBOYD did some logs on his car while it was on Awesome's rollers in early December. I did some comparisons on his figures between dyno bhp and Air flow to see how good the rule-of-thumb formula was.
The thing that jumped out at me was that airflow increases right up to the limit, whereas dyno bhp has fallen away quite a bit before that.
Martyn quoted a max g/s for a KO3S before - surely that's dependant on the level of boost.........
But..... could the quoted figure g/s be at max bhp rather than max revs?
I thought the max g/s was purely the max amount of air the turbo could flow full stop?
I suppose your right.... Interesting that the formula for bhp usually bandied around is g/s x 1.31 - so 170 g/s would be 222.7 bhp. - whereas I seem to remember it being said that 240bhp is was the max for a K30S..
Yea, I guess you're right...roughly 240bhp would equate to ~183g/s through the MAF. Still the formula isnt 100% accurate though is it...
i know its not revo but .......
this is my third gear log 2500 rpm to redline tracking g/s
5 198.01 2240 121.1 14.62 58.39
198.91 2520 166.2 18.7 85.64
199.82 2840 182.7 20.4 97.06
200.72 3160 182.7 20.74 109
201.63 3480 179.7 20.4 120.47
202.53 3760 170.7 19.72 124.28
203.44 4040 172.9 20.4 135.97
204.34 4320 172.9 20.4 141.19
205.25 4600 172.2 20.06 151.44
206.16 4840 170.7 21.08 157.58
207.06 5080 172.2 22.1 168.44
207.96 5320 172.9 21.76 175.69
208.88 5560 171.4 21.08 183.58
209.78 5760 169.2 23.8 184.56
210.68 5920 149.6 21.76 163.58
Peaking at 184 indicating about 235-240 bhp which is supported by 2 rr days.
my spec is similar to u guys tho
my peak flow of the log is
313.97 6400 153.4 19.38 188.72 not sure what gear but flowing 188 g/s
Mafs do read up and down a bit depending on the entry to them, and how turbulent the airstream is.
Temperature also makes quite a difference. Turbos will probably be rated at standard temp and pressure, but are a volume device.
Obviously on v cold or high pressure days, the same volume will equal more mass.
A maxed out k03 realy isn't that far behind a k04 maxed out. K03s will give 1.9bar absolute at 6500, k04 will give 2.1 bar. In other words it will shift about 10% more air, peak flow. So 10% more power.
If daves seing 185-190, then a k04 should see 205-209 peak. (I've seen it)
Nice that, Alex - it pulls max g/s earlier - at under 6k rpm.
yeah that was before my dp and cat, ill try and do another log for u now its on.
i tend to change it 5700 or 6500 depending on my mood but pre cat and dp my max torque and bhp was aliitle lower.
dave dont forget that on the rollers that measure whp even tyre pressure on the day can affect it iirc so u could have put out the same or similar to saul just car setup issue
Borg-Warner spec was 0.17kg/s (170g/s) for K0-3 (not K-03s) and 0.21kg/s for K-04. Max boost & max flow aren't necessarily at the same point. I'd imagine the max flow would be at a very low pressure ratio, maybe even 1, due to turbine size restriction.
Ah ok! My bad!
How the hell can you get 170g/s out of a K03?
and if you had no ignition timing to go with all this boost what do you think would be the result?
i have already seen 160+ on cars with k03
and i hope a k03s can do better than 170g/s
i'm interested by the answer to this question