boost figures

[brett craig]

cheers for the advice smithy, its not the rip i'm worried about. i had to cobble some silicone pipe together for the idle control valve, i cant see a leak but to be sure i'll put the standard kit on and rule it out. then i'll pull the pipework for the boost gauge to make sure theres no kinks or traps.

i'm sure when i had the mbc fitted it only hit 10psi aswell. i put 1 turn on it last night and it feels quicker but only 11psi, i'm going to put 1 more turn on it tomorrow and if it still onky gets to 10/11psi i'll leave it at that as i'm not going to destroy the engine.

if in standard trim with just the ecu i get the same results then i'll pop over to hlm, sort of a process of elimination without the expenditure if you know what i mean ?

[brett craig]

well the plot thickens !!!

replace the recirc plate and 2 other leaking hoses and now have the following.

1st gear 5psi
2nd gear 9psi
3rd gear 13 psi

figure that one out ? lower than standard boost in 1st but higher than standard in 3rd onwards

[mightywolf]

are you sure theres not a problem with the boost gauge?

[brett craig]

lets just say it wont even spin in 1st so it cant be far out, its realy not quick at all

[wallace570]

try a new boost solenoid will cost about £50 i think or if u have a friend thats got the same year of t5 try theres out

[brett craig]

well i'm nearly 100% sure now that its the ecu, by my logical thinking i figure that if the bcs,maf,actuator were faulty and not allowing it to boost pass 10psi then i should still get 10psi in every gear and no less. as it is mapped for 15psi in 1st and more after this.
i spent the whole of today with the car in bits and triple checked/tightened every clamp,hose,joint. cleaned the maf, and checked dizzy arm and cap again, and all is perfect, every boost hose is new and it drives totaly smooth and revs clean, its never actualy run aswell as this but the figures of 6psi in 1st, 8-9psi in 2nd and 10psi in every other gear is exactly what the standard figures should be.
i cant get over with the car to hlm due to work so ive emailed nat and hope to post it back to be checked whilst on my next holiday, fingers crossed its just a ecu thats been overlooked or just marked up wrong, if not then time to get my wallet out again.

[SAMXPJ]

For what it's worth I got a different boost figure [2lb] when changing the maff for another used one. I would think that with more or less corrosion on the maff wires then the change in resistance seen by the ecu as the air is flowing over the wires is being interpreted as more or less air going into system and the fuel will be measured accordingly. I have often wondered if putting a resistor in series with the maff would fool the ecu and change the boost figure? Has anyone done any testing on these maff's?

[pjaystar]

having the same problem with mine replaced maf plugs cap rotor leads coil no air leaks and will not boost over 10 psi with an mbc fitted it feels slugish and the boost drops mine also has an hlm chip let me know when you get it sorted mate

[brett craig]

well fitted a mbc today and the boosts straight up and strong so i tihnk i can assume my bcs is shot !

[smithy]

leave the mbc on it mate and set it to 1.1 to 1.2 bar and keep the boost pipes from the turbo to the mbc short to stop boost spikes .

[Jamest5r]

well fitted a mbc today and the boosts straight up and strong so i tihnk i can assume my bcs is shot !

Thank fu*k for that mate, glad your getting somewhere.

[brett craig]

would you ££££££££££ believe it, out tonight and went to 16psi in 3rd, and the bloody clutch slipped !!!!

it never rains but it pours, time to be gentle with it till jan when the mot is up and it'll be off the road having a new engine, suspension and brakes anyway.

[smithy]

get the clutch warmed up and it will hold better .i nackered my clutch on the rollers and then raced at avon with a slipping clutch and still pulled a 14.4 .