Author Topic: Think my car is over boosting  (Read 1647 times)

Offline rfn_hodgson

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Think my car is over boosting
« on: 22 December 2013, 22:19 »
As above lads I think my car is over boosting..... Before it used to peak at 20-21 psi then fade out but now I have noticed that it is reaching 25-27 psi

Only really noticed this since doing ultimate vac delete and front mount

What could be the possible out come to this and what sort. Of parts would I be looking at to replace if needed?

Once again thanks in advance :)


VW Golf MK4 1.8 Turbo AUQ 203 BHP-more now :) , ultimate vacuum delete, Forgre 007p-new piston, Oil catch can, s3 boost set up, FMIC, silicone TIP, full turbo back exhaust, stage 1 map, lowered on V-maxx coilovers  audi tt Quattro alloys

Offline Scott D

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Re: Think my car is over boosting
« Reply #1 on: 24 December 2013, 00:33 »
rough guess but could well be a boost leak causing it to overboost in order to make requested amounts.
2003 1.8T GTI 180 - APR Stage I, S2000 Filter, R-Tech Supersize TIP, Bilstein B12 Suspension, 18" OZ Superleggera, Recaro Heated Leathers, US Spec Rear Lights, N249/SAI/PCV Delete

1.8T AUQ - 241bhp & 286 ft-lb
R-Tech Map, Forge FMIC, SFS Oversized TIP, Ported Manifold, Milltek Turboback non res exhaust, Forge 007p, N249 & N112 delete, SAI delete, S2000 Air Filter, Sachs clutch & Lightweight Flywheel

Offline Wazzzer

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Re: Think my car is over boosting
« Reply #2 on: 24 December 2013, 08:52 »
Is the MAP sensor plugged in


1999 1.8T: R-Tech remap - 225bhp/256lb/ft : K03s : THS FMIC : THS PCR pipe : 2.5" stainless exhaust : THS FR3 Engine mounts : G60/VR6 clutch : Calibra Yellow injectors : VR6 MAF : Devils Own WMI : Forge 007p : Carbonio CAI : Leon Cupra R Brembos : FK AK Street coilovers : Votex skirts : Anniversary front : click ---> http://www.golfgtiforum.co.uk/index.php?topic=92175

Offline rfn_hodgson

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Re: Think my car is over boosting
« Reply #3 on: 24 December 2013, 10:18 »
The map sensor is plugged in as I've got the part of the s3 piping were the map sensor goes

And boost leak...... I've gone over all boost pipes and made sure they are all tight joints... There is pretty much no vac lines left apart from the obvious and those are all secure.

Any one know were I can get a smoke pressure test done?


VW Golf MK4 1.8 Turbo AUQ 203 BHP-more now :) , ultimate vacuum delete, Forgre 007p-new piston, Oil catch can, s3 boost set up, FMIC, silicone TIP, full turbo back exhaust, stage 1 map, lowered on V-maxx coilovers  audi tt Quattro alloys

Offline Wazzzer

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Re: Think my car is over boosting
« Reply #4 on: 24 December 2013, 11:05 »
You shouldn't overboost as the MAP sensor should tell the N75 via the ECU to ease off the boost...


1999 1.8T: R-Tech remap - 225bhp/256lb/ft : K03s : THS FMIC : THS PCR pipe : 2.5" stainless exhaust : THS FR3 Engine mounts : G60/VR6 clutch : Calibra Yellow injectors : VR6 MAF : Devils Own WMI : Forge 007p : Carbonio CAI : Leon Cupra R Brembos : FK AK Street coilovers : Votex skirts : Anniversary front : click ---> http://www.golfgtiforum.co.uk/index.php?topic=92175

Offline dom

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Re: Think my car is over boosting
« Reply #5 on: 24 December 2013, 11:23 »
You shouldn't overboost as the MAP sensor should tell the N75 via the ECU to ease off the boost...

Faulty N75 then?

Offline Wazzzer

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Re: Think my car is over boosting
« Reply #6 on: 24 December 2013, 11:31 »
May well be, would be worth trying a working one off another car if poss


1999 1.8T: R-Tech remap - 225bhp/256lb/ft : K03s : THS FMIC : THS PCR pipe : 2.5" stainless exhaust : THS FR3 Engine mounts : G60/VR6 clutch : Calibra Yellow injectors : VR6 MAF : Devils Own WMI : Forge 007p : Carbonio CAI : Leon Cupra R Brembos : FK AK Street coilovers : Votex skirts : Anniversary front : click ---> http://www.golfgtiforum.co.uk/index.php?topic=92175