tyrone coupe

Hey guys,

I need help my car is tuned for 7.5psi and gets this at altitude with no overboost problems (+1500m above sea level).

The problem is when i drive down to sea level the boost keeps climbing to over 11 psi (I have a stock motor), I have to keep backing off to ensure the boost is kept in check.

my set up is:

APS TT
3" APS exhaust
APS plenum
Unichip Q

any ideas on how to fix the problem.??

Zivman

iTrader: (19)

why are you running the big APS exhaust on a stock block for 7-8 psi???? makes no sense, that exhaust is overkill for people running 14 psi. that is your main problem, that and the fact you probably weren't properly tuned for that huge exhaust

z3gga

Tyrone,
when Craig tuned my GTR in jhb the boost was set at 1.05 bar on high and 0.9 bar on low boost, once i got home to Lusaka, approx 500-600metres lower altitude than jhb the boost kept rising to 1.15-1.25 bar, way too high for the stock R34 turbos on pump gas, the boost controller easily sorted that out though, i then got it to boost at 1.1 bar high and 1 bar low boost without any issues, if you don't have a boost controller try investing in 1, Craig offers the HKS one which is quite steep imho, if you want a slight cheaper one i picked up my Greddy profec B spec 2 from Autostyle for approx 2000 rands...

Cheers,

Suhail

With regards to what Zivman said above, i know Craig is also running the APS Exhaust on his TT Z and as far as i recall from my 1 ride in his car boost hardly crept over .6 bar, so if tuned properly i don't think the exhaust should be an issue

Zivman

iTrader: (19)

if he gets tuned for it, it should take care of the issue. The out of box tune is not really optimal for that much exhaust and the duty cycles in the boost control will have to be brought down accordingly

tyrone coupe

hey guys,

the car was tuned for the boost and at altitutude there is no boost creep the problem on comes into play when I drive down to the coast.

I may just have to get a boost controler.

thanks for the input guys.

zzerotwosixty

iTrader: (4)

You could change the wastegate springs before you go to the coast.

tyrone coupe

Boost is controlled by the unichip boost control module.

waste gate springs will not have any effect ,we need to look at a way that the boost control module can see the same boost at the coast and at altitude.

my tuner will look at it this weekend and hopefully we can find a solution that i can share with the rest of you guys.

sentry65

iTrader: (11)

from what I've heard, you want to adjust the gain of the boost controller to let power come on a little later in the rpms to get a handle on controlling overboost

TENGAI

iTrader: (5)

Forge actuators / springs, ebc, and UTEC (or nicer ems) FTW. At a minimum, get the Forge actuators...

http://forgedinternals.com/store/pro...cat=254&page=1

KPierson

iTrader: (1)

How much time do you spend at the coast? If you are primarily concerned about engine damage you can remove the fuse to the boost control solenoid. This should drop you down to spring pressure alone, with no boost control. Spring pressure alone will give you the absolute minimum boost you can run on the APS. You will drop in performance a bit, but your motor will be safe.

The other option would be, like posted above, to go with an EBC. This will give you much more control over boost then the Unichip.

tyrone coupe

I think I have decided to go with and EBC

that way I can limit boost in 1st and second gear as tranction is such a problem (I know get better tyres).

DanielW

iTrader: (27)

which ebc did you go with?

z3gga

Tyrone, how much Bhp is your car putting out at the hubs on Craigs dyno and at what boost?

Abishop

iTrader: (19)

the absolute pressure is more at sea level