scoby_hugh

Iv bought a saph cossie with a t34 with a .63 turbine housing, 3 bar map sensor, bosch 803 injectors and a bayjoo chip its running 28 psi boost.

The problem im having is the car comes on boost its quite good but not properly smooth like it should be and makes loads of power right before the limiter so i feel the power curve should be better (more mid range pull) but i can live with that for now, the main problem is that when i come off the throttle in boost i do hear some reasonably loud chatter. Its only got the factory recirculating dump valve so would you think for this spec a decent dump valve would stop the chatter (which i assume is the turbo stalling)

I know the chip is basicly a bodge and it will never run right so im going to get it mapped when i can get round to it but as i live on guernsey its going to be a while before i get over to do it so im just looking to fix the surge/stall for the moment.

cheers

martysmartie

iTrader: (1)

Correct, It's actually the compressor wheel stalling due to the back force of the excess boost being forced back through the turbo when the throttle closes trying to spin wheel backwards. A dump valve address this issue by "dumping" this to atmosphere hence better for your turbo especially with boost your running.

It also keeps turbo spooling between gear changes rather than "Stalling".

If you know chip is dodgy I would not be driving it hard as you may loose your engine., as you say defo get it setup ASAP.

You will get for/against dumps as every thread has had on here concerning dump valves, some maintain there is nothing wrong with running high boost without one, fact is it DOES shorten life/damage your turbo.

Martin

scoby_hugh

Thanks for the help mate i was looking at getting a recirculating dump valve but if a normal one will be better il go for that, i can definately notice it looses boost between gears, where would the best place be to get it mapped also? Must be fairly close to the south as il probably get the boat to poole,

thanks

martysmartie

iTrader: (1)

Depends if you want a live map or just an off the shelf chip, live map will be better but much more expensive. If you know spec of car you could just buy a chip to suit, MSD sell them, DIY fitment and all you would need is to check CO etc after.

Alot of people ditch the standard Bosch recirc and buy a single piston type instead from the likes of Bailey, I have one myself and they come anodised as well.

Martin

scoby_hugh

to be honest if the standard ecu can be mapped well enough il go for that, how much roughly would that cost? and wheres a good place near the south?

cheers

martysmartie

iTrader: (1)

Some tuners can't live map L6 but are plenty that can, most only know aftermarket stuff, I don't know anyone from that area really, someone will be along though that will.


I think a live maps normally around £500

Martin