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Mk5 General Area / Re: K04 Conversion - Do you ever regret it? How is it for daily driving?
« Last post by OllieVRS on March 25, 2024, 12:05:13 pm »Your boost does seem to be slightly too low from the requested boost, by a few hundred mbar. So there is definitely an issue with boost somewhere. Mine is at most -150mbar from requested when accelerating fully, usually +-50mbar.
Also remember that it's most useful to subtract ambient atmospheric pressure when talking about boost numbers, 1000mbar, e.g. my peak boost boost is 16 psi/1.1bar in my graph.
As for octane, I think mapping on that is equally at fault for the disappointing performance.
In Ireland we only have 95 octane, so if you want more octane here you have to use octane booster. So nearly everybody maps on 95 octane. Back when my car only had a cold air intake it was measured 184hp stock, then 225hp stage 1 (on dyno). When using measuring engine torque in KW via VCDS later, I estimated adding expensive octane booster to make the octane 99 only raised HP by 8-10hp on my 95 map. But the car felt a lot more responsive, and the timing was less retarded so the engine sounded more aggressive. Adding the 200 cel sports cat and another mapping raised the 95 octane power to 235hp, so max 245hp with octane booster.
Online tuners give their numbers for mapping on 98/99 octane, so if you see 'Stage 1 250hp or Stage 2 275hp' they are talking about the car running on a 98/99 map, that can't run 95. Nobody ever gives numbers for 95 octane mapping unfortunately. So if you're making ~230-240hp on a 95 map (on 99 fuel) that's probably realistic numbers.
If I had easy access to 99 octane, I would map for only 99 octane. And I would expect my stage 2 to be ~275hp. '270-275bhp' is a fantasy for stage 1 with no engine mods, your tuner may be overestimating to make his map sound better than other tuners.
Only way to know how much power it's actually making is to go to a real dyno. If that's not an option, you can log Mass Air Flow g/s (act.) and Engine Torque Nm (act.) in VCDS next time you do your log, that can *estimate* hp, but it can be inaccurate.
Also remember that it's most useful to subtract ambient atmospheric pressure when talking about boost numbers, 1000mbar, e.g. my peak boost boost is 16 psi/1.1bar in my graph.
As for octane, I think mapping on that is equally at fault for the disappointing performance.
In Ireland we only have 95 octane, so if you want more octane here you have to use octane booster. So nearly everybody maps on 95 octane. Back when my car only had a cold air intake it was measured 184hp stock, then 225hp stage 1 (on dyno). When using measuring engine torque in KW via VCDS later, I estimated adding expensive octane booster to make the octane 99 only raised HP by 8-10hp on my 95 map. But the car felt a lot more responsive, and the timing was less retarded so the engine sounded more aggressive. Adding the 200 cel sports cat and another mapping raised the 95 octane power to 235hp, so max 245hp with octane booster.
Online tuners give their numbers for mapping on 98/99 octane, so if you see 'Stage 1 250hp or Stage 2 275hp' they are talking about the car running on a 98/99 map, that can't run 95. Nobody ever gives numbers for 95 octane mapping unfortunately. So if you're making ~230-240hp on a 95 map (on 99 fuel) that's probably realistic numbers.
If I had easy access to 99 octane, I would map for only 99 octane. And I would expect my stage 2 to be ~275hp. '270-275bhp' is a fantasy for stage 1 with no engine mods, your tuner may be overestimating to make his map sound better than other tuners.
Only way to know how much power it's actually making is to go to a real dyno. If that's not an option, you can log Mass Air Flow g/s (act.) and Engine Torque Nm (act.) in VCDS next time you do your log, that can *estimate* hp, but it can be inaccurate.