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Model specific boards => Golf mk4 => Topic started by: davegolfturbo on 23 September 2009, 23:22

Title: over boosting in 4th and 5th gear
Post by: davegolfturbo on 23 September 2009, 23:22

my car is now running a custom map on a hybrid gt2x turbo (300bhp, 320 ft/lb torque!!!) from wayne schoffield (chip wizards)

He mapped the car to run around 1.5-1.6 bar boost, which it does in gears 1,2 and 3 but for some strange reason my turbo gauge shows that it boosts all the way to around 1.75 in higher gears and i even experienced it just under the 2bar at around 6000 rpm. he mapped my car so the boost would stay in all the way until just before red line to get the most out of each gear, he said he did not need to raise the redline limiter as it was peaking before!

 Now i know if the car was pushing 2bar of boost on my turbo it would not be good for the turbo or the engine. but how reliable are these boost gauges? i mean wayne is a very eperienced mapper and he knows his stuff, could it maybe that my gauge is not accurate as he would of been reading the boost from the computer not relying on a gauge, and set the fuelling accordingly to make sure it wouldnt over boost...any advise and/or opinions would be great,

thanks dave.

Title: Re: over boosting in 4th and 5th gear
Post by: topher on 23 September 2009, 23:55

i think yours is an AGU? if so then no map sensor to worry about.. but you cant log requested/actual boost either. you could log maf values though, and test n75 duty cycle (if it's that a digital boost controller might be a handy gadget with that turbo in it's place)

which hose is your boost gauge plumbed in to?

Title: Re: over boosting in 4th and 5th gear
Post by: RnP on 24 September 2009, 12:59

i always thought that live mapping a car and mapping it on the rollers would always have certain factors that would arrose such as outside temps which could see boost spiking,