All MK1 S/c's will run out of puff using the oversize pulley's mainly due to the charge temp being super hot.
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This leads to detonation, detected by the knock sensor, which in turn retards the timing.
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The ECU also switchs the injectors to 100% duty
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(basically full on!) to get as much fuel into the cylinders, and acting to cool the charge.
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This results in a loss of power and RICH running.
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.
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.
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.
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However.
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.
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.IF your fuel pressure is low at high revs, then the engine will run lean and you'll probably blow the HG or worse within a short time, if you're wellying it everywhere.
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.
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.
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!
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The SC 4AGZE engines have a lower power peak than the NA 4AGE
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(5500rpm S/C compared to 6600 N/A, iirc?), so revving over this will basically not get you any more performance.
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.
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.
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.
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.
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To utilise the extra boost, you need mod the mapping, either using a standalone EMS or a piggyback.
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Either way, you need to change settings.
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.
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.
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.
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.
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To run a DECENT oversize pulley setup you NEED to do the following:
1) improve your intercooling 100%, either a larger IC in a DECENT airflow, or a W2A chargecooler setup.
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2) make sure you have a rising-rate FPR fitted AND
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(crucially) that it has been set up on a rolling road.
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If you feel
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"experimental", get hold of a dash mounted fuel pressure gauge.
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Try to get an electric one with a sensor rather than one which has the fuel line running into the cabin!
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Then watch what happens to fuel pressure at high revs: it should remain at least over 37psi right to the redline
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(well.
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.
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.5500rpm).
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If its less than this, you're gonna have problems.
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.
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.
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You could fit an inline fuel pump
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, or simply upgrade the stock one
This may have been done already, but it pays to be aware.
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.
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.
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Been there.
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.
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.done that!
![Wink :wink:](./images/smilies/icon_wink.gif)