PAZ

hi all got a 3 door stage 3 320 bhp.had it rolling roaded all fine ,its got a stage 3 msd chip with the boost set to 25 psi.the question i ask is can i turn the boost down to say 21 22 psi of boost with the same chip and not have any probs ie fuelling.i only ask as i would rather reliability than performance many thanks paul

tabetha

Yes, boost fuelling is added dependant upon signal from MAP, so less boost less fuel, same thing as not putting your foot down as much!!
It will be totally reliable at this power level though.
tabetha

cossiegreg1

what tabetha said ^^^^

Karl

It depends on your stage 3 chip. Best to call Stu with the serial number and ask him. The reason I say this is I have seen many stage 3 chips which run the greens at maximum fuel map duration from 1.4bar. This means that if the car was fueling fine at 25 psi (1.7bar), turning down to 21 psi can result in an overfueling condition.

I have tested many cars with this kind of stage 3 chip and they are often running mid 10's AFR at 21 psi as a result!!! Bizarre I know but very common in the cosworth tuning world!

reisskahn

As Karl has mentioned could run shite/overfuel depending on the chips map etc as mine did previously. So worth asking MSD what the crack is with the chip though if setup properly it should be reliable enough if in doubt just get it checked over by someone

Either way best of luck

tabetha

Just another reason to ditch the piece of shit weber mareli then ?
Aftermarket ecu can do so much more and a lot cheaper than having a few more features added to an atiquated system.
Personally I would not have any chip with a spike either.
tabetha

Karl

tabetha,

It has nothing to do with the weber system, simply the mapping being incorrect for the engine.

It is people's ignorance that leads them to knock the weber marelli system, when in fact it is still an AMAZING system on a cosworth. (And I map loads of ecu's besides cosworth so have experience of many different ecu's with which to compare the weber system with.)

tabetha

The weber is shit when compared to a modern ecu and the pointeless task of trying to upgrade it, to end up costing as much as a new ecu, but still with a LOT less features.
But hang on that is what I said, sorry for repeating myself.
I can get a ecu from a company that puts the weber marelli in the shade big time, and no disrespect to yourself but they designed their own system and of course accordingly know it inside out, unlike some other ones that become unsupported as soon as the newest version comes out.
They have clients bringing cars from other countries just to be mapped, those cars are competing VERY successfully, testament to the abilities of both the ecu and the mapper/operator.
This company like yourself put thier customers first, and that is where my money is going, going LPG anyway, as 31PENCE A LITRE off me mates farm!!
tabetha