I'm just wondering what causes boost spike?

My 2 wheel drive Cosworth sometimes spikes the boost up under load It's hard to describe but in higher gears it boosts up 1.3 bar and blows out the spark I don't mind a spike as long as the boost comes down to the preset limit if you know what I mean.

I re-gapped my plugs to 0.6mm because they were gapped at 1.1mm and it still did it and I've now fitted a Group A coil but I haven't tested the car yet.

My car now has a -31 actuator on it and it holds 1 bar/15psi nicely but sometimes it spikes and you have to back off and then apply the throttle again, it also did this as standard with a standard actuator.

Would adjusting the actuator rod either way control the spike? I thought that it would but I wanted to check before adjusting anything

This afternoon I am going to check the vacuum hoses and make sure they are all tight etc but I want to make 100% sure the car is A1 rather than just trying to get around the problem.

Sorry if this post is hard to understand

Thanks

 

Very small jubilee clips are real good for making sure those vacuum pipes are tight, mine used to come off all the time.

 

I went around under the bonnet last night fitting clips where they were needed None of them have come off though.