Turbo Boost Cutout

No,

I had the BBR Chips for a while, Martin will confirm but I think it was fuelling mainly.

Thanks Martin, but Sir is just fine laugh...

Ok coffee time.. here we go...

Actually the BBR chip does not alter the boost cut, and nor can it as this falls outside the 512 byte PROM you are referring. The BBR chip is essentially fuel map changes for an otherwise standard engine arrangement. The map and code is somewhat dated, and is known to run lean and I wouldn’t suggest running it. Superchip never actually produced a “chip” as such, nor modified the map tables, but in fairness I won’t discuss this further in an open forum. Again this is not a suggested change for those actually looking to increase performance as a package with proven robust improvement.

The internal / external piggy back board mentioned in this thread is really not a technically competent and robust approach to modern tuning. It’s a fix / bodge, what ever you wish to call it, and it was a simple way of fooling the ecu to not cut the injection drive, and hence not cut the engine power. As owners we owe it to ourselves to use the best information, knowledge, and technology available, and this mod is not that in spades. Effectively it reduces the MAP pressure signal fed to the ECU, and hence prevent the dread boost cut. But this also means the fueling supplied to the engine via the ecu is incorrectly calculated, as it is using a reduced MAP value than the actual MAP value! To over come this error in calibrated fueling against actual MAP, the poor soul is encouraged to fit an adjustable fuel pressure regulator to increase the fueling again... this really is a comedy of errors... the ecu should be re-calibrated, and can be, to provide the correct fueling against actual MAP signal without any fudge. Lee has posted the link in his post to the way it is done.

The significance of the MAP signal, is this is the only input to the Renix 1 (GTA turbo) that tells it what the engine load is at any moment in time, and hence what the correct fueling and spark advance should be - it changes both parameters, it does not have airflow monitoring.

...the following is note worthy:

"ECU - best advice ditch the mod. I can explain how to do this in a pm if need be. I have worked on these extensively, and that mod will mean you never have the correct injector duty cycle for the manifold pressure applied to the engine, and consequently will run lean. There are in fact only 4 real positive pressure load lines (taking you from atmospheric to X psi), and depending on the setting of the board gain setting pot "Superchip fudge" you may not actually hit the last one - bad bad bad.

A quick search will pull up some old posts where I have gone into much more detail.

http://www.renaultalpineownersclub.com/ ... s&start=15

I hope that explains, but in my opinion you would not be best advised to fit any piggy back - period, sorry guys.

I agree Martin that this is not the ideal way to modify, but for a cheap way of getting a decent chunk of power for next to nothing I don't feel it posts any danger to the engine if its set up correctly. And I don't know if the BBR ECU mod changed over the years but the one they fitted on my car did take out the boost limit - circa 1990. As long as the car is set up with an eye on the air fuel ratio I can't see why you would have an issue with this set up. I ran my car with this mod, a hybrid turbo and adjustable fuel reg for many years without a problem. Culminating in a 258bhp run on Van Aaken developments rollers when I fitted my charge cooler

Tony, yes agree, but how many owners do get their setup checked and professionally adjusted, most of these mods get bought and sold, passed on and just fitted. Yes the more discerning will setup their cars, but one would hope, with the better alternatives for the money these days, those would be the routes taken to achieve better results; let’s not forget those mods were never cheap, especially for what they were... I think as a body of enthusiasts that we should try and advance the technology and gain better performance as things move forward, we all benefit.

It was one of the reasons I suggested a club Rolling Road day before, but it needs people to get behind it.

The boost cut defeat is achieved in changes to the electronics, not the chip, and hence can be done without any reprogramming. There are two versions of the BBR chip, not a great deal between them though.

But in essence, yes you are right, it all comes down to what you wish to achieve, totally accept...

Scoff has just moved into new premises and is fully set-up to do RR days + offers a bit more than just the usual print out .
I can sort it with him if the club wants to book a day and we can get a few cars in various states of tune there just from The Rat Pack
http://www.efi-parts.co.uk/index.php?show_aux_page=10