Hybird turbo's

[wez]

Originally Posted by [b

Quote[/b] (Martin F @ June 14 2004,16:57)]Having that VSV on the wastegate actuator removes progressive opening of the wategate valve as boost increases. When the VSV switches the wastegate should open pretty rapidly and reduce boost pressure.

Obviously this is a simplified explanation as IIRC the wastegate VSV works on a PWM signal.

Exactly right and with the AEM you can control this VSV along with all the others.

As for the PWM this allows you to dictate how much air/pressure is allowed to act on the waistgate by varying the amount/rate the solenoid opens and closes.

[Nathan]

Martin's got it right. The stock system, which even itself is pretty crude compared to an aftermarket boost controller, is still a LOT better in terms of boost control than a bleed valve which as you say pretty much give the boost they feel like depending on what colour pants you have on. The big downside is you can't play about with gain controls as Chief explained and this can have a dramatic effect on how and when the turbos spool. Having a decent boost control system also means they sit bang on whatever you tell them to which is fairly important when healthy Soops love 1.2 bar but can and will det on 1.3 (many will argue the toss because they can't hear it though)

As for going beyond 1 bar on No1 I agree, it will be working hard but we let them sit at what they want to TBH when we fit EBC's. It's not really worth playing about for X amount of time (well, not paying us to do it but the customer can if they want) to worry about 0.1bar on No1. It's not a longevity/reliability issue as far as I am concerned as Jap turbos can and do go pop when they feel like it and steels won't care at all. As for loss of performance, I don't agree although I accept that you may not actually make any more power at 1 bar as opposed to 0.9.

Trollage? You got long green wispy hair then?

[Nathan]

Originally Posted by [b

Quote[/b] (wez @ June 14 2004,17:04)]Exactly right and with the AEM you can control this VSV along with all the others.

Stock VSV's aren't really much good for anything other than stock boost IMO. They are slow to react and don't like being pulsed- in fact they are designed to be off or on really unlike say the HKS EVC stepper motor which really does shift.

In fact I'd wager that most drivers could tell the difference in boost response and peak boost hold with an EVC even only peaking on stock boost levels.

[chiefgroover]

What have i done? what have i started? lmao.
damm it, i'll weld the actuators closed and make a big ramp, hopefully i'll break through the earths atmosphere in the low 10's, lapping the moon at warp factor 9 on opposite lock leaving black doughnuts so watch the night sky for the banded moon!. Nat, Mr.Scott (after reaching warp drive) will e mail you the egt's and afr's from our built in satellite station, and if you think they a bit odd, we can beam you up for some fine tuning!.
Supra boost control...............thats a subject that could start a war, I'm glad we can laugh about it

[Syed Shah]

I still think a MBC is the way to go, as long as you have a boost guage, it is fine. Not to say it is any bettert han a EBC, but it does the job reliably and holds osst well, all you *need*, though not the gadget most *want*.

[Martin F]

Originally Posted by [b

Quote[/b] (Syed Shah @ June 14 2004,14:54)]MBC does the job just as well.

OK

Originally Posted by [b

Quote[/b] (Syed Shah @ June 14 2004,22:39)]Not to say it is any bettert han a EBC,

Hmmmmmm.

In fact i think there is quite a difference between an MBC and an EBC just like there is quite a difference between a ball & spring MBC and the traditional ?4.99 bleed valve.

A ball and spring MBC will still progressively open and allow pressure to act on the wastegate actuator just not to the extent of the bleed valve. Also how do you change the boost setting on an MBC ?

Maybe i'm fortunate enough that my car already came with the DSBC, but being able to floor it (once setup) and see the boost sit at 1.35Kg/cm constantly with very little fluctuation had me sold.

[Ian C]

I was under the impression that the stock wastegate VSV simply opened at a set pressure level to stop wastegate creep. It's either open or shut, it doesn't get pulsed. Is this correct or not? I mean, has anyone verified this by logging the signal, not just theoretically?

I have an Apexi boost controller and it can't hold boost to save it's life. The datalogging I've been doing shows, despite me setting it to 1.3bar and feeding it a reasonable duty cycle, a variance from 1.1 to 1.3bar under WOT in 3rd gear. I used to slag it off because of this but lately I've been thinking it's more to do with the hybrids outgunning the stock wastegate so much that even with the restrictor ring in place the boost fluctuates so much the boost controller doesn't really stand a chance of maintaining a set level Goalposts always moving and all that.

Bleed valve may well do the job, and is very tempting when you compare prices, but I'd still err on the boost controller side if your wastegate can flow enough.

-Ian

[wez]

With the AEM I was able to control the stock waistgate VSV using PWM and hold boost at a steady 0.9bar on turbo one and then 1Bar with both online.



I am also planning on using the stock VSV with my single as I am currently using my right foot for boost control.

[Martin F]

Originally Posted by [b

Quote[/b] (alex h @ June 10 2004,14:59)]There is a first turbo mod...which I have used. But it does require trial and error to test. Parts needed are 3 lengths of silicon hose a T piece and a bleeder T valve...here is a picture.

I didn't realise that this mod is actually listed on MKIV.com as well.

First Turbo Boost Mod

[SKI]

I just had my car set up by C.W with a bleed valve and it holds boost perfectly at about 1.15 bar without exception.

Turns out (on a really positive note), according to Chris who test drove my car, that my concerns over T2 coming in late with a bloody great big whack where the result of the previous owner fitting hybrids at some point. Chris had a good mess under the bonnet and the car runs great. On the subject of hybrids I?ve never driven another Soop so I?m not really able to comment on how different they feel, although froma performance perspective I do seem a fair bit faster then other cars that I would expect to hold their own, regardless of my BPU. When Chris was explaining to me what he had done he said that there were some very odd things about my car, perhaps reflected in the fact that it wanted to boost up to 1.5 bar when it was first modified, fortunately this was immediately corrected after it scared the life out of me

I also have RLTC fitted (by Chris who did a very tidy job), that really is the dogs bollocks especially in the wet, no more twitchy rear regardless of boost, would recommend it to anyone, Phil Wall (knows the system inside out) can do you a modified dat file for any situation, even snow for autos