APEXi AVC-R not working on first Turbo?

[CanisLupus]

As the name says, it seems that the AVC-R does not Control the boost when the first Turbo is alone after the transition with both everything is working fine, boost is controlled as set.

 

Anyone some ideas?

 

p.s.: The HKS BC before controlled the First Tubby too.

[wojtrek]

from what I know, you need two boost controllers in a supra - if you install just one, before the actuator on the first turbo you will control boost after transition. you need a second BC for the first turbo and you plug that to the pressure feed on the second turbo actuator. here's where it's all explained:

http://www.max-boost.co.uk/max-boost/supra/boosting_the_beast.htm

[Arron]

You only need one AVCR or equiv EBC, if is been fitted correctly and set up by someone who has the correct knowledge and its not working then it must be an actuator problem. Its common on the TT's for the actuators to play up. First things first, get someone to make sure the AVCR has been fitted correctly then if thats ok you more than likely have an acuator problem. Apart from that check for leaks in turbo pipes etc. Do a search on the forum for testing actuators. Good luck mate!

[heckler]

boost controllers on a sequential system - are plumbed into the 2nd turbo, as on the supra its the 2nd turbo which has the wastegate - so this need for 2 BC is pile of poo.

[CanisLupus]

You only need one AVCR or equiv EBC, if is been fitted correctly and set up by someone who has the correct knowledge and its not working then it must be an actuator problem. Its common on the TT's for the actuators to play up. First things first, get someone to make sure the AVCR has been fitted correctly then if thats ok you more than likely have an acuator problem. Apart from that check for leaks in turbo pipes etc. Do a search on the forum for testing actuators. Good luck mate!

 

I fitted the BC like this diagramm says. I've got it from http://www.mkiv.com. Checked also if everything is right again after seeing the issue with the first turbo not being controlled:

 

 

Is this the right way for controlling both turbos before and after transition? Or would this be just for the second?

If so what would i need to change to control both of them?

 

After some testing today i saw that the first is running stock apparently and when second kicks in it boosts to 0.8, 0.9, 1.0, 1.1 and so on depending on what i set the boost and duty cycle.

[wojtrek]

if you have it connected as on the picture, then you are connected to the first turbo. this is how I had it to control boost above 4000rpm. so if Arron and heckler are right, and you can control boost with one BC on both turbos, then this is surely not how you do it. I have never seen any instructions on how to control boost on both turbos in sequential mode with one BC. I mean, I want 1.2bar above 4000rpm, so I set the BC for 1.2bar, but this means I also have 1.2 running on the first turbo alone before 3500rpm, and this is killing it very quickly, they say - so, how do we do it?

[CanisLupus]

Would be interesting how. The guide is not really helpfull as i want everything controlled by the EBC

without any second MBCs or smth else :\

Anybody some idea how to connect the AVCR to controll boost over the complete Revs and keeping the pre spool for the second Turbo?

[Ian C]

if you have it connected as on the picture, then you are connected to the first turbo. this is how I had it to control boost above 4000rpm. so if Arron and heckler are right, and you can control boost with one BC on both turbos, then this is surely not how you do it. I have never seen any instructions on how to control boost on both turbos in sequential mode with one BC. I mean, I want 1.2bar above 4000rpm, so I set the BC for 1.2bar, but this means I also have 1.2 running on the first turbo alone before 3500rpm, and this is killing it very quickly, they say - so, how do we do it?

 

The wastegate is in the first turbo housing, yes, but don't confuse this with it only controlling boost on the first turbo. It only comes into play when both turbos are online, and it bypasses exhaust flow around BOTH turbos. This means a) it only controls boost above 4000rpm and b) it controls your maximum boost pressure.

 

The first turbo boost pressure is controlled by the exhaust gas bypass valve on the second turbo. This bypasses gas from turbo 1 to start spinning up turbo 2. If you try and up the pressure on turbo 1 you sacrifice prespool on 2 and can make the transition harder on the turbo as it's shocked into life, and introduce some extra lag because of this.

 

I don't know how you're seeing 1.2bar on the first turbo under 4000rpm as that control circuit has nothing to do with controlling turbo 1 boost. Also you are right to be concerned. I've never seen any dyno testing for upping the boost on the first turbo. I know that detonation due to overheating the intake air occurs very quickly if the second turbo doesn't come online, so I'm dubious as to how useful upping the boost would be. I tried it back in the day on mine and it seemed to slow the car down, probably because timing was being frantically pulled by the ECU due to knock.

[CanisLupus]

So there's no option to control both with one EBC without sacrificing Pre Spool?

[Ian C]

Well you can't get something for nothing To hit a higher boost, more exahust goes through turbo 1, which means less goes through turbo 2's bypass valve, so it doesn't spin as fast, so the transition hits it harder and has to spin it up from lower rpms. That means more lag. The actual amount, though, I've never measured.

 

I've posted on this before though - raising the boost in the first turbo isn't a good idea, it's on the edge of efficiency anyway, I tried it and the car got slower... Timing was pulled due to detonation. You can try using a bleed valve on the bypass valve, which will up the pressure, but without some way of accurately checking before-and-after power levels (and also making sure you aren't getting detonation) I really wouldn't chance it.

[CanisLupus]

Hm okay, don't want to kill the second Turbo and if first would be out of efficiency it's not worth it anyway

 

Thx Ian

[Scott]

Here is somethig strange, since you are in this thread Ian you may be the man to ask...

 

Fitted a MBC to the car today, finally. At first it wasn't set correctly, I should have checked, so I was getting boost spikes up to 1.3bar in 2nd gear. The thing is, when it was set like this, I was getting 1bar from the 1st turbo.

 

Before I added the MBC I was getting 0.7bar at both stages in 2nd, with it in and set wrong I got 1.0bar and 1.3bar in 2nd, when re-set correctly I am now getting 0.8bar then 1.1bar (1.2 spike then settle) in 2nd.

 

Obviously I still have to fine tune it so that I don't spike too high in the higher gears but I thought I would mention it due to the previous discussion. Something is definitely happening with the 1st turbo, I felt it pulling like a train on the first turbo also. The bum dyno is telling me that 0.7 to 1.0bar in the 1st tubby DOES make a difference

[Guest Snaps]

I thought it was common knowledge that supra's only have one wastegate... maybe not.

 

The reason the first turbo doesn't see full boost (set on the AVC-R or EBC) is because of the Exhaust Bypass Valve (as Ian said) which prespools the second turbo.

 

Also, the first turbo is the one that has the wastegate, not the second. First turbo is the one at the front of the car, second turbo is the rear.

[Scott]

It is Snaps, what made you think otherwise

 

The wastegate being held firmly closed until 1.2bar DOES see a rise in boost from the first turbo though, I could probably video it if you like. I'm guessing without the boost controller on the actuator the wastegate flutters a little bit, keeping the boost in the 1st turbo down.

[Scott]

Got a video of 1.3bar at 3000rpm in 6th gear this morning. All I have controlling the boost is 1 ball and spring MBC between the 1st tubby housing and actuator. I let off right after obviously, just wanted to show it.

 

1st tubby is pulling like a train, it'll be coming down at lunchtime though lol.

[wojtrek]

OK, here's how my first turbo reacted to raising boost (from 0.6 to 0.9bar). I got the TD04 hybrids. the blue graphs are power/torque for 0.6bar for 1st turbo and 1.0 - 0.95 bar after transition, and the red graphs 0.9 and 1.1-1.0 respectively.

 

http://img27.imageshack.us/img27/1251/mochybrydybezkatvsdodan.th.gif

 

Uploaded with ImageShack.us

for those who don't understand Nm, it's 450Nm = 330 ft/lb on the first turbo at 0.9bar. it's 275 at 0.6.

also, once the MBC is fitted (red/brown) you can notice that the turbo spools quicker. it's especially noticeable at part throttle, almost instant boost...

[Scott]

Yup, I finished setting up my MBC yesterday and now see a clean 1.0bar from the first tubby. 1.1 from both in the lower gears and 1.2 from both in the higher gears.

 

Car is running as sweet as a nut now that the faulty VSV has been swapped out.

 

I'll try and remember to get that video posted, it's scary stuff

[CanisLupus]

How did you raise it? Manual Boost Controller?

I'm looking for a way to raise it with the APEXi if possible in any way.

[Scott]

Yeah, ball and spring manual boost controller. I didn't do anything special at all, I just connected it between the tubby manifold/actuator and bobs your goldfish.

 

The ball and spring type works by releasing no pressure at all until it sees 1.2bar of pressure at the manifold end. This keeps the wastegate completely shut. Not sure if the AVC-R works in the same way or not? I know the bleed valves don't hence why they don't work as well.

 

I don't know how to explain the boost gain from the 1st turbo. Everything is working better than it ever was on my car thanks to 1 VSV replacement. The transition point is around 3800 and it is extremely short making things very smooth.

 

Hope you get it sorted

[CanisLupus]

Hmz got to have a look how the APEXi works and if i can use it for the first also.

Anybody some tips on that? Should be some good work figuring it out on my own

[Scott]

I'm confused, did you misunderstand what I wrote? You can't use the Apexi to control 2 sets of boost variables, you can only use it to set one, as stated earlier. If the Apexi doesn't give added boost to the 1st turbo as well as the 2nd automatically then there is no configuration that will make it do otherwise.

 

It all has to do with how the boost controller on the Apexi limits the boost to the actuator.

 

Also, it would appear my car may be a freak of nature if noone else has the same output by adding boost control.

[CanisLupus]

Ah k Misunderstood then.

 

Does the HKS BC work in another way then? While it was fitted i got high boost on first turbo also the transition seemed less violent. Is my car a freak too then?

[Scott]

I would maybe go round your VSV's bud. It might be something to do with them. The offending VSV was the EGCV VSV IIRC. The one at the top of the engine bay held on with 2 bolts top and bottom (The big vsv, not the samll one at the rear of the engine bay, at 90 degrees).

 

HTH

[Scott]

Oh, have you checked the solenoid is working properly? Holding boost OK etc?

[CanisLupus]

Since i removed the HKS and put in the AVC-R the first turbo boosts stock and second the way i configured the APEXi so no real issues.

 

With the HKS(where the hoses were connected different but don't remember how sadly ) it boosted 1.2 on first turbo(pulled like a train really impressive) and after the transition it was stock boost was far as i remember.

 

The car is running fine(holding boost etc.) ATM the only thing is that the transition seems a little less violent and i want more boost down low with the possibility to change it from in the car.