S2 ABY Wastegate Spring or change it when fitting the RS2 setup?

[orsum]

I have completed the S2 to RS2 conversion with all original parts.

The one part I have not thought about until now is the Wastegate Spring. Is the standard ABY spring ok or should I change it and why.

My car has been fitted with software by Prj, RS2 Turbo, 440 injectors and 3" DP.

I have not run the car yet.

[GazzaG60]

think the gate has the same spring in it. basically the dc on the boost solenoid limits the opening of the gate. if an issue is detected the system goes to wastegate pressure of 0.4 bar IIRC as a failsafe

[Error404]

ABY / ADU spring is that same, leave it alone

[orsum]

Good to know they are the same.

Thanks

[UrS4boy]

Some people like me, either remove the small cap on the top of the Waste Gate and turn the spring perch down 6 turns *OR* (me) replace the stock spring with a 1.9 Bar spring from 034 and turn the perch all the way up. Helps with initial tip in (to help minimize the extra lag with the RS2 turbo). YMMV.

[Jonas_R]

Dave I would think that would mess with the boost map from prj?

[Error404]

Well it just defeats the factory safety routine in the event the ECU needs to cut boost to protect the engine.

[newsh]

Dave I would think that would mess with the boost map from prj?

Only if the ECU finds it can’t reduce actual boost to requested. If it can’t it may go into limp mode.
PRJ usually maps with a stock spring so I would leave it stock.

[Jonas_R]

Only if the ECU finds it can’t reduce actual boost to requested. If it can’t it may go into limp mode.
PRJ usually maps with a stock spring so I would leave it stock.

Are you sure our motronic works this way and that it is just not a duty cycle that is set to say bleeding x% air?

Reading Mr. Nugents boost control:

https://www.s2forum.com/forum/techni...rol-essentials

If it actually can reduce the WGFV duty cycle on the fly so to speak. Then I would think there is a risk of boost spike when going WOT, since it will try and bleed the same amount of air but that will result in higher boost pressure due to the stiffer spring and it might not catch it. And then you would also have a system that is adjusting a lot more all the time then being closer to the requested boost.

Anyway I would not mount a stiffer spring, if you want to do it then talk to PRJ about first.

[orsum]

Will check with Prj

Thanks guys

[UrS4boy]

Well it just defeats the factory safety routine in the event the ECU needs to cut boost to protect the engine.

Nope. The safety routine is still in place and it will limit the maximum boost. You didn't read what I said. "1.9 Bar spring from 034 and turn the perch all the way up". *IF* you add the 1.9 Bar spring and leave the perch in the factory position, the rate of boost rise on initial WOT is too fast for the ECU and it cuts boost until it is happy and then it tries again and so on (all in milliseconds). I have been telling that story since 2006 if anybody ever listened. Still running full RS2 hardware and MRC RS2 Stage 3 software (289 whp, about 350-360 crank)

[Error404]

If you run a stiffer spring rate, whether by adding preload or a stiffer spring you will increase the mechanical boost level beyond factory spec. You can’t have it both ways.

[newsh]

True, if you use the 034 1.9Bar spring it will fail safe to 0.9Bar instead of 0.4 (or a little lower if you unwind the WG bolt.)

[UrS4boy]

If you run a stiffer spring rate, whether by adding preload or a stiffer spring you will increase the mechanical boost level beyond factory spec. You can’t have it both ways.

Gosh. I will have to tell myself that the last 10 plus years of running the 1.9 bar spring have been unsafe (or whatever you are trying to tell me).


It's been fine. The ECU and N75 WGFV are still controlling the boost just fine (MRC RS2 Stage 3 limits max boost to 26 psig boost (something like 1.9 Bar boost (relative, not absolute)). Needs the best gas/petrol that you can buy.

[newsh]

I use the same spring as you in the Nothelle Dave, with RS2 SW and it’s not wound all the way up. I like the 1 Bar boost at part throttle, the car feels very flat with a stock spring in it.
If I drive around gently for a while then slam the throttle it will spike, so I don’t do that if I can help it. Working up to full throttle it’s fine.
When Mihnea used to map a lot of these cars he always fitted the 1.9 spring before mapping, he had a big box of them.

In the coupe I’ve got an MRC RS2 custom tune but with the GT30 and a big spring and just use an eboost 2, 1.5 Bar is plenty..
The eboost just works like a massive spring so if the throttle is open at all it just boosts. I like that.