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bugz

By bugz,
in Engines & Forced Induction

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Adriano Grand Master

Adriano

Posted
Posted

Depending on what rpm you are changing gears at, it could be falling below the boost threashold, which would explain slow boost build. Also running an atmo bov will still effect the running, as it still has an AFM, which will result in super rich a/f ratios, whilst maintaining fairly high ignition values. Neither of these are good for maintaining turbo shaft speed.

A tuning trick which works surprisingly well, is to tune the cells where it hits on gearchange to run 5 deg BTDC running 12:1 AFR, this give a poor mans anti lag. Just make sure it isnt the same cell where you cruise on the freeway.

vic_sky33 Enthusiast

vic_sky33

Posted
Posted

just to touch up on that subject, would it make a r34gtt auto yes auto, if i was to change the standard bov for an aftermarket one, can i make the boost come back quicker. She s a bit slow once i shift the ttronic to a higher gear ?

Fry_33 Proficient

Fry_33

Posted
Posted (edited)
does anyone here use antilag? I just got a PFC Pro version which has that feature will be interesting to play with, will it drop at all between gears?

The PFC Pro version has 'launch control'. It only works when your speed is 0kmph. You set the RPM that you want it to work at say 4000rpm. If you put your foot flat to the floor then it will sit a 4000rpm like a rev limiter. It just retards/cuts ignition and therefore the air-fuel mixture ends up igniting in the manifold/turbo which spins it up. I don't really use it as I don't want to kill my standard turbo.. yet.

The Pro version also uses ignition cut at redline instead of fuel cut like standard ones.

Edited by Fry_33
blitza Collaborator

blitza

Posted
Posted

when you change gears you have to take your foot off the throttle, you lose all of the pressure(boost) inbetween the compressor side of your turbo to your intake manifold. when you put the throttle on after the gear change, your pressure(boost) has to build up again. The bigger the turbo, the more time it takes to build up that pressure again...

Kranker Collaborator

Kranker

Posted
Posted

...your dont "have" to take your foot off the throttle....

like joeyjoejoe said, flatshift the bastard haha!

But seriously, its what a turbo car does, you dont make boost when your not on the throttle.

Change gears at higher rpm, double clutching and doing faster changes might minimise the effect, but its not exactly gentle on the car.

Nothing much you can really do to keep the turbo making boost while the throttle is closed.

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