Scott.T

iTrader: (2)

Oops That should read 94 - 96 STi RA

The reason I ask is I have just read the map from an STi RA and it explains why my usual 15.5psi map only achieved about 12-13psi

My usual 15.5psi map runs a duty cycle of approx 62% above 4,000rpm and this hits 15.5psi very well and has been fitted to approx 80 cars over the last couple of years using ScoobyECU or 27C1028's (although it has had some minor refinments over the years).

This same map was put into an STi RA and it struggled to reach the standard boost level of 13.3psi

Now that I have read the map out the answer appears to be the duty cycle, because the standard map runs a massive 72% duty cycle to only acheive the 13.3psi target boost levels.

The same map profiles has been put into countless other ECU without problems, but then for example the Z4 (12.7psi) only run a duty cycle in the mid 50's

All I can read into this is that the STi RA has some sort of VF turbo instead of the expected TD05. But is must be pushing out less air then a TD05 to require alot more air to be bled away.

The early STi RA is a bit special because it has intercooler spray, adjustable diff, strut brace (same as later STI but different to STi Version 1), quick shift box, flappy roof vent, forged pistons etc..etc....
I couldn't read anything off the turbo yesterday.

Any clues ????

P.S My usual 15.5psi map has worked fine in a 94 WRX RA and in later 96 RA'a so the STi must have something different going on.

David_Wallis

Scott.. you've stuck a map on a car, but you dont know what turbo it has?



David

Pavlo

td05, although the state of the actuators do vary

Scott.T

iTrader: (2)

I think anyone on here would of assumed it's a TD05. The car is boggo standard AFAIK and the owner knows.

The Acuator may be a good point, could be worth checking if it's got adjustment.

Scott.T

iTrader: (2)

it has so at leasst we can spin a few turns on it.
strange it would be set so weak as standard tho'

Delboy2

A weakened spring maybe??

Cheers

Scott.T

iTrader: (2)

Nope, because it runs the standard 13.3psi target fine with the standard map.
But then, as mentioned above, the standard map runs 72% duty to achieve this. Whereas the 12.7psi Z4 map only runs mid 50's and my 15.5psi/16psi map runs low 60's.

wrc78

Different restrictor, maybe ?
I guess it is the same wastegate solenoid ?

Fabrice.

Pavlo

Sti map uses much higher duty cycles for boost control, but it also has lower corrections for over and under pressure too.

Paul

Scott.T

iTrader: (2)

The restrictor could be playing a part in it, but I think I'll just up the duty % because we've run out of adjustment on the actuator and still hitting less than 1 BAR.

quicksprint

Scott...if the restrictor was missing would this cause the problem? As whoever plumbed in the boost guage cut and tee'd it into the vacuum pipe that goes to the actuator.
Is it possible that the restrictor was removed or lost?

steve

Scott.T

iTrader: (2)

No restrictor would give more boost on an <MY96, because it would cause more air to be bled away from the actuator.

It works in reverse to MY97-MY00 (and onwards), because on these the restrictor is between the Actuator and turbo outlet nipple and actuator. As opposed to the bleed pipe from the BCS.

Steve's car hits target boost of 0.9BAR fine on the standard map. But then the STI RA Standard duty cycle is a v.large 72% (for 13.3psi). I think the issue is with the actuator used/rating for this application.

quicksprint

Scott...do you want me to get you a direct fit Lamda sensor? (i take it yours is fitted in the D/P)....i have to ask because i have been caught out before!!!

I can get it and bring it with me to Steve's on saturday if you like.

steve

Scott.T

iTrader: (2)

By Direct fit I assume you mean it's a Bosch part with the correct connector for the car i.e not a universal that needs wiring into the existing loom.

I know the MY00 connector is different to my old MY94, but you can release the crimps from the connector with a small screwdriver and swap them over.

Yes mine is in the DP (as was my old MY94) and should normally be a 3-wire (although my universal is 4-wire).

I've been waiting for bosch to release the OEM one for a while, because I know they do a universal 3 & 4 wire. But wanted to try and get a genuine Subaru one (which is Bosch anway), but not a Subaru prices.

Let us know what I owe you, and if you could leave it with Steve that would be cool. I can collect it when we next hook up.

quicksprint

Sorry but just been informed that Bosch do not list a direct fit type for the UK models..only for models upto 1996!! WTF
Bosch do make them as OE but are not selling them to the general motor trade.
I should be able to get you a NGK universal 3 wire...these are good quality,have fitted a few with No comebacks.Let me know if you want one.

Scott.T

iTrader: (2)

Upto 1996 will be fine as long as it's for the downpipe.
I had my MY94 one in there before I stripped the thread doing a Downpipe swap.
I think the prob tip is of a different design but AFAIK it works fine.

Jolly Green Monster

iTrader: (4)

think the only difference is the length of the cable on the one that fits the headers and the one that fits the downpipe.

so different part numbers.