Boost Spikes, Even After The Waste Gate Porting?!

[tichman]

cheers, I'll give that a go on the weekend.

[tichman]

Hey bomber, gave that a go, blocked bov pipe with 1" bit of broom handle and plugged the vacuum line but after a few go's on it it's the same thing just a lot of flutter with bov blocked off.

Took turbo off and was hardly open at 10lb from airline, about 30degrees at 15 psi. Rod from actuator wasn't lined up with pin on flapper arm properly either putting a sideways load on the rod that wouldn't be helping it move to freely I'd have though. Realigned snail to bring the rod inline with the pin.

Have taken the 5lb spring out of the actuator leaving the 7lb in there and now on 10psi its open as much as it was on 15 on the 12lb springs, at 15lb from the airline its well and truly open so think that will solve the overboosting to 17 once running through the solenoid again, looking to go around the 13lb mark.

Will reassemble tomorrow and road test.

[tichman]

Just an update, dunno whats causing this still as with just the 7lb spring in the actuator, at wot from 2000 rpm in 3rd gear manual mode (4sp btr) it goes up to 8, then 10 and climbs up to 15 creeping to 16 at 5000-5200 rpm. It pulls cleanly in that scenario but when in D and giving it slow but steady throttle it does the boostcut dance on the guage, up/down repeatedly and in quick succession. This happens with actuator plumbed both direct from turbo and/or going through solenoid which is disabled anyway so no surprise there. Will be sending pcm back to tuner for tweaking to see if we can get this spiking sorted out as when it pulls clean it runs well.

Still well keen to hear of anyone elses solutions to this if there is any. Cheers.

[tichman]

Can anyone shed some light on this issue, I've pm'd Gazza to se if he had sorted it on his car but didn't get a reply. Have just got the pcm back and from start car idled at 1500 (maybe resetting the itself?) test drive and it is still the same, seems to be even more prone to this flaring boost on gradual throttle application, wot from 2000 rpm sees the boost climb clean to 8 then on to 15+ as the revs/sped increases.

On the new inlet piping I've got the blow off valve in front of the map sensor by 300-400mm, so the map is between the bov and throttle body. Could this be having any effect?

Also of question is the new Garret turbine housing with 35mm flapper valve which seemed like a new off the shelf item and not my old housing ported with 38mm flapper valve as requested by the people that did it in Auckland (who also supplied and fitted the 12lb TS actuator). I did ring them when I got the turbo back prior to fitting it and the tuning etc and questioned the size of the flapper and hole and was assured it was ample for what I was doing and they had sold a lot of them with no problems reported.

This is starting to p-ss me off a fair bit as there seems to be no light at the end of the tunnel and looks like I'm going to have to make another trip back to Auckland to the tuner......

Anyone know of this problem and the solution to it???