Steve, to avoid overboosting, make yourself a pressure dump valve using cheap 35-40mm blow off valve, just remove the diaphram and put a stiff spring in it with an adjuster bolt for winding up the spring force. You fit the BOV into the intake pipe (pre intercooler, to help dampen any air surging from affecting the MAP sensor readings at the intake manifold) and adjust the spring to about 1-2psi above your normal boost pressure. When you start over boosting, it will dump pressure and snap shut again, doing this repeatedly to keep your boost under control. Albeit this is a rough solution, it is a very simple thing you can make up, throw in your tool box and if you have any issues like you run into at the last moment, you can fit it into the intake and go racing.

Thanks mate,
Much appreciated. I understand thats something that was used in F1 and considered it over the weekend but didn't eventuate as the BOV is next to the throttle body.
When are you going to get out there racing?
 

Yes its rough and will result in the turbo just blowing a whole load of hot air producing less power and exacerbating the intercooling issue you already had.  What turbo is it and which wastegate?

Its a GTX3071r with a 40mm Synapse Wastegate. It has more to do with the spring rate in the wastegate than anything else. Now it has a screamer pipe the fluctuation has dropped off. Once we fit a 10lb spring, we can see if the exhaust design is the weak link then go from there.
The guy who is onboard with the fabrication work stated the exhaust is a poor design but Im not interested in spending more cash.Just want to modify what I have (if required) and run with it.
Intercooling is another bane. Its something I need to look into when the time is right.
Thanks James

Great to see all went, some what, well! Annoyed i didnt make it up to watch.
Pitty for a few faults to pop up, but fantastic result to finish.
 
As the saying in motorsport goes, would you rather finish first and not know why? or finish last but know why?
 
Thanks for the great update, would love to hear more on each of those topics about things you have learnt!
 
As for electronics, yeah always a easy thing to fail with no warning and stop the car dead. For those reasons ive spent a tonne on all my electronics, autosport spec wiring, PDMs (solid state, no fuses or relays) and lots of data, on paper is bullet proof, but things can and do still fail, suppose fault finding and repair is quicker tho, but thats my hobby, i am a cabler, my number plates are 'cabled' and grown up with a family of auto elecs.
 
Whats the reason for going back to glass rear window? Heat i assume, did the perspex start to melt? 
 
You mention new engine lid also, did you make a new one recently without the ic vent, to be able to see with the rear view mirror, or do you mean you still have to make that one? 
 
What is the 300 like as far as rubbing mirrors and hero / non owner drivers not afraid to rub panels?

Thanks mate,
It was very annoying when you pay a tuner to do a job and he does a **** job, costing you countless hours trying to chase a problem. IT really put a lot of pressure on the weekend where we should have been chasing set up instead of overboost. Pretty annoyed about the whole tuner issue but the rest of the weekend was good.
So you a cabler? Im pretty sure you mentioned this at some stage but I very keen to discuss what is needed to rewire the car so its bulletproof from vibration, heat from engine and heat from extreme load through the wiring system.
I would like to have a plug on the firewall which can be removed when removing the engine, a surge protector in case of short circuiting which can damage the ECU/data logger/memory cards, heat shielding for all wiring in the engine bay, clamps for connectors so they do not fall off(cost me 20+ minutes when it happened on Sunday).
The fuel fuse blew due to working so hard it overheated the wiring. So when fitting the fuel pump, use the largest wiring you can so you reduce the risk of red hot wiring in the fuel tank! It also suffered fuel surge after 50 laps so a swirl pot and external fuel pump will be added at some stage. Also going to add a 10ltr aux tank to get us to the halfway mark to help with overall results.
You are right regarding the rear window. The lexan unit did not like the heat so the stand unit was fitted from a safety point of view. It will not leak, will not melt, is far clearer and looks a hell of a lot better!. The weight difference is nominal. about 3kg.
We installed a newly fabricated aluminium engine cover with dzus clips, which would heat up then expand making it difficult to remove and install in the race when everything was at operating temps. Its a lot better than the old unit as you can now see clearly out the rear of the car and the other drivers can see you which is a big plus. Will have a pic availableover the weekend.
There is a full alloy undertray which scoops up into the engine bay providing terrific cool air management which then escapes through the new vented engine cover.
Will have some pic's up soon. As we made this undertray and engine cover just hours beofre leaving for Wakefield, it wasnt tested until we hit the track. It needs some tweeking to improve clearances and access to the engine bay with a separate unit from under the driver seat to the engine bay to improve efficiency when working on engine. A re-enforced fibreglass or carbon unit would be better, two peice with improved quick release mounting points. You could see it working when we drove in the rain. The flow rate exiting the car was far more uniform due to the undertray.Just need a difusser from the subframe to the back of the car. It also reduced noise in the car.
As far as driver manners, its pretty good out there. Most of the time accidents are caused by people exceeding their abilities then hitting someone, not seeing someone coming up behind you, but no real malice. It does happen from time to time but overall, its pretty good. The advantage of the enduro is, people know is a long race and are in conservation mode from the start, they drive thier own race and all is good. If there was any convern, it the BMW drivers who are more agressive. One took out a Datsun 1000 with a 1.8 litre fitted. Really banged it up but he kept on going and finished the race.
Are thinking of entering when your car is done? 
 
 
 
 

Thanks for the info.
 
As for the wiring, prob best to call me one day if you wanted to talk about and get ideas for re wiring, firewall connectors ect as i could type all night long and only brush on the topic, but there are cheapish ways to do it, and of course very very very expensive ways to do it.
 
Doubt ill enter an event like the 300, not to keen with door to door racing, maybe events like 6 hour regularity races tho

Thanks,
 
Will give you a call in the next week. I found a supplier which I can 'check out' tomorrow as its just around the corner from a callout I have tomorrow.
 

Here are some pics of turbo coolant/oil lines.


Engine cover and undertray. They both worked quite well but the undertray will need to be replaced with a lighter two piece system.

The car is at the exhaust centre having the exhuast manifold set to the correct piping for twin scroll application, a screamer pipe will be fitted with a 50mm ID and V band fittings to the dump pipe.
Im also going back to the 5lb spring and a few other little mods to help with boost management.
It will be back home next week were the wiring will be looked at before going back out for a drive. Will not see the track for a month.
Here is some footage from the Wakefield 300. Its only the start and the first two laps but its a standing start where I 'cane it' in first then a little in second. After that I was short shift till my stint was over.
Will have more footage soon.
http://www.youtube.com/watch?v=kX-n2a68GAg&feature=youtu.be