boost spiking?

[Adey aka Ewok]

so what the cause of boost spiking? been trying to get the car to hold 18-19psi, in first and second its not a problem get to third and it creaps up from a 4500rpm onwards from 19psi round to 21-22, not good really as i dnt intend on running the boost that high. read somwhere that i could drill out the wastgate hole so that its slightly bigger so letting out more gasses, would this help?

[Andrew Cooke]

have you got so much preload that the wastegate can't open very far? Grab the arm with a spanner and see how far it can open.

[Adey aka Ewok]

ahh didnt think of it like that, i have had to shorten the arm a fair bit to get the desired boost, it took a big leaver to get it on the wastgate arm too

[Adey aka Ewok]

ok so if i have to wind my actuator arm back out to get the full swing on the arm how should i go about raising the boost back up?

[RICHIE]

can you change the diameter of the vac pipe to create more boost

[Adey aka Ewok]

can you change the diameter of the vac pipe to create more boost
would that work? thought the actuator opend with pressure? is the pressure not the same irrelevant of the pipe size?

[D4WNO]

I'm sorry, I thought the thread was called "Bruce spiking" so came in to have a laugh :laugh:

[Adey aka Ewok]

lol @ dawn. i feel like a noob again playing with these 5s a few years or running round with ecus efis and solonoids has really dumbed me down to the old skool cool of renault 5 tinkering

[paul-11turbo]

ok so if i have to wind my actuator arm back out to get the full swing on the arm how should i go about raising the boost back up?


better actuator or a bleed valve.

[Adey aka Ewok]

brand new -31 unit on there

[Markey Mark (BD)]

You could plumb it up differently mate to get more boost, i have a way of doing it which gets a fair bit of boost out the standard actuator.

[Adey aka Ewok]

do tell?

[Markey Mark (BD)]

do tell?

Do you still have the OE actuator and carb top mate?

If you do run a pipe from the front port of the carb top to the front por of the actuator, then run one from the back of carb top to back of actuator. Block off the one half way down the carb.

Try it like that and see what boost you have, if its still not enough you could remove the restrictor in the back port of the carb top that way you have more pressure holding the actutor shut.
If you find you have too much boost with the restrictor in adjust the actuator back out and if still too much you can fit a bleed valve in the back pipe to bring it down further.

Not too sure if people have done it this way before but it has worked for me quite well. To give you an idea i've had the standard actuator hold 24psi before like this

[Adey aka Ewok]

has anyone had this by having a very dirty and cloged air filter? Im asking as last nite i removed mine and now flat out in 4th and 5th it holds 18psi? Il pop it back on and try it with it on again just to see

[Andrew Cooke]

haven't you got an electronic boost controller kicking around?

[Adey aka Ewok]

nope tho i did used to have a blitz unit that was quite good, will have a look around see if they are still available