1978 Fisher Fury - whoosh!

Mini-update, mainly as it's been a month since my last post!!

The adjusted wastegate actuator was still allowing nearly 12psi, which according to the chap doing the tuning is fine for a std MX5 engine, but not for the injectors I have fitted.

Here's me testing the actuator as scientifically as I could think of



Not really wanting to cough up on a set of bigger injectors and also because it's pretty f-ing fast as is, I plumped for an adjustable actuator to bring the boost down to within the fuel system capacity. I also discovered the position of the actuator can was causing the movement of the arm to be obstructed.





The new actuator is a cheap one, similar to a mambatek, supplied with springs of different ratings. I've fitted the 0.3 bar spring to see where we get to. I took the opportunity to lower the actuator body, away from the bonnet, and made a cranked actuator arm to make sure the motion is smooth.





The result of this, after a few data log drives, is that I'm seeing 4psi at ~5k rpm, but it's rising fast. Next step is full throttle up to 7k - that's proving hard with how wet it has been and how damp the roads are!!

Once that's all bottomed out, I'd like to increase the boost until I get around 8psi.

Other fantastic news to report is that it starts brilliantly from cold and is driveable immediately - the initial goal from this whole malarkey!!

Thanks!

The hardtop has taken a back seat, I've been out round the block a couple of times to get this tune sorted so the bits haven't been on the car for a while. As the weather gets darker and wetter I'm sure I'll get into it again. There's another reason which I'll get to in a minute!

As for the tune, I got up to 7k revs, but the boost was climbing and climbing so something wasn't right.

I checked the wastegate actuator and it opens under a whiff of pressure from the bike pump, so that's working.

I started to wonder about an exhaust restriction and then the tuner mentioned bad wastegate port shaping, especially with the Chinese stuff. This would definitely describe my symptoms, the wastegate can't actually dump exhaust gases, so the turbo keeps boosting.

I checked my old turbo



Big flap, small hole, doesn't look very promising, hmmm.

Then in a flurry of activity, I removed the turbo and split the turbine housing off.

Same deal



And from the other side



So the plan is to open the hole up a bit and blend the entrance side to ease the flow for the exhaust.

Hoping I can have it back together fairly quickly!

The other reason I've been distracted, and not bought materials for the hardtop, is I've bought another car and marginally overspent! It needs some weld repairs and a few other bits buying, although I'm hoping I can enjoy as is over the winter

I'll start a thread soon, but ultimately, this may get sold to fund a build...