[Flavio]

Went to the Dynojet today but was unable to boost higher than 1.3 bar reliably. I use a Blitz SBC-iD boost controller and have the SP57 with a PHR Stage 1 fuel kit (720cc, dual Walbro pumps).

When the SBC is completely disconnected the boost flies up to over 2 bar so I don't think something is wrong with the wastegate.

When the SBC is connected and you set boost high (like 1.5 bar or higher) it starts to regulate the boost very up/down when boost is over 1.3 bar. It is like a zig zag, goes from 1.5 to 1.2 nad then up to 1.5 but not very fast. It makes no difference whether I use manual or automatic mode on the Blitz, it is unable to keep the boost up.

We think it might have to do with the amount of T's we have used. The vacuum line that goes to the power steering is T'd twice to connect to the boost controller hose that goes to the boost controller display and also to connect to the vacuum hose for the APEX'i electronic boost gauge.

The stock BOV nipple is T'd triple. Once for the pressure sensor for the water injection kit. After that it is T'd for the BOV and after that for the input of the Blitz boost controller solenoid box and the HKS wastegate. The output of the solenoid box is connected to the wastegate as well.

Another possible culprit could be the Hose Techniques hoses I use for all of these vacuum lines. It is very flexible. Is it really suitable for these high boost lines?

Could the amount of T's be the problem? If so can someone explain why?

I know most single turbo installations use a HKS EVC boost controller but the Blizt is rated for 2.5bar so should be suitable for my installation.

We also checked the BOV but it does not leak when the fluttering happens, it is clearly the wategaste that opens and shuts.

Any suggestions would be greatly appreciated.

Flavio

P.S. Best dyno result was 460rwhp at 1.23bar (17.8psi). This was with a nice curve so no zig zag at higher rpm's.

 

[Silver Orchid SP60]

Your first T is the problem. Do not use the power steering hose as a boost source. T off of your boost pressure sensor hose. Run that hose into the the car for your DSBC and then T the boost guage from that. My DSBC works like a champ. I have pushed as low as 1.0 to as high as 2.0 with no problems.

 

[Flavio]

Your first T is the problem. Do not use the power steering hose as a boost source. T off of your boost pressure sensor hose. Run that hose into the the car for your DSBC and then T the boost guage from that. My DSBC works like a champ. I have pushed as low as 1.0 to as high as 2.0 with no problems.

Hi Ced,

So you don't think the T's at the solenoid box and the wastegate are the problem? Where have you tapped the lines for the solenoid box, wastegate and BOV?

Flavio

 

[Silver Orchid SP60]

Hi Ced,

So you don't think the T's at the solenoid box and the wastegate are the problem? Where have you tapped the lines for the solenoid box, wastegate and BOV?

Flavio

There is only 1 T on my wastegate/boost soleniod connection. The IN side of the solenoid is T'ed to the side of the wastegate and a nipple on my intercooler pipe. The out side of the solenoid is going straight to the top of the wastegate. I dont have the stock BOV. The HKS racing BOV is using the stock BOV input. The solenoid should not be connected to the vacuum source for the BOV. If there is not a nipple on your turbo for an input then take the input for that from the intercooler pipe.

 

[PMD]

The 57 is wierd in that it is so fast, boost controllers seem to have a problem keeping up with it. I had the DSBC on my 57 and I switched to the HKS ez, because I thought it wasn't working well. I heard a "fluttering" sound and after checking everything in the world, (missing, detonation, lean rich etc) I figured it was the wastegate opening and closing very fast. The HKS ez makes the same sound, but does seem to control the boost a bit better, and they only seem to have the problem when the boost hits hard at first. On the DSBC if you turn down the gain I believe it will control it a bit better, but you slow down the spool, and that is what I wanted to avoid doing. The other thing about the DSBC is that the boost pressure sensor is in on the control unit, the HKS one is on the part that mounts in the engine bay, being closer to the source, I thought, would be a bit better. I have the veilside hood, so with the top off I hear EVERYTHING in the engine bay and it was driving me crazy. It only seems to happen in the 1.2-1.5 range, and you can hear the boost controller stuggling to keep the boost down. I also had the sp60 for a while and this turbo never did it, and I have had 2-57s and they both make the same sounds. One more "problem" with the DSBC, is that if you use it as a boost guage, it is harder than hell to read, because it displays, 1.xx bar, and the xx are never consistant, it displays every minute change, which bothered me. I guess it is just the price you pay for super spool

 

[Flavio]

I switched the boost gauge and boost controller vacuum lines to the turbo pressure sensor (as Cedric suggested) and at first I thought that solved the problem. Up to 1.5 bar the problem has gone away but above that the boost still flutters and bounces tremendously.

I am going to change the vacuum line for the BOV and will try again.

I would still like to know however if the Hose Techniques hose I use is suitable. It seems too flexible.

Flavio

BTW I have the Blitz SBC-iD not the DSBC so readout of the boost is not a problem. It is strange however that the APEX'i electronic boost gauge reads higher than the boost controller although they are both connected to the same vacuum line and both display in kPa or bar.

 

[PMD]

does the boost gauge bounce around as well? or is it just the display on the Blitz boost controller? Another thing to check is the spring on the wastegate? Have you stayed on the gas, to see if you can pull through it? On mine after a bit it gets the boost under control and the noise stops, took me a long time to try that, I thought I was missing at first If we had some info on how the solinoids work in the boost controllers, it might help.

 

[sidwin]

Sounds like youa re not having enough valve lift. You need to back the wastegate spring all the way out and do a couple of runs and see what the boost is set too. Mine creeped up to 20 psi with the controller turned off. With the screw backed out i hit 11 psi.

Sid

 

[Flavio]

Sorry guys, I don't understand what you mean. The boost gauge as well as the boost controller show the boost bouncing around.

What do you mean by checking the wastegate and how should I check it? How can I measure if it is set at the right level?

Flavio

 

[PMD]

on the top of the wastegate, off the downpipe, there should be a bolt of some type, by tightening or loosening that bolt, you control the tension on a spring, thus controlling when the wastegate will open.

 

[Brad Mayo]

I had ALOT of trouble with the small spring for the KHS wastegate in the kit. With my AVCR off all I could make was .7bar. I'd hook it up so it'd just use the wastegate spring and still only .7bar even with the spring backed all the way out. With the AVCR maxed out to 90% duty and the spring all the way out I'd only see ~1.4bar. My guess is the spring is too small and the boost controller is fighting itself to make/hold boost. I was gonna get the bigger spring and probly will at some point but for now I just got a ball and spring manual boost controller. IT IS AWESOME! I got it to make and hold 1.4 bar in 4th and havent fooled with it since. Spool is much better too. I'll never use an EBC again. Now I can turn the boost up as far as I want.

 

[PMD]

Any idea what 1.4 bar is in terms of rwhp? I run that on pump gas around town, I checked it with a wide band o2 and I am still a little rich, but I never checked the rwhp.

thanks

 

[Brad Mayo]

1.4bar on 93 octane was 506rwhp and 479rwtq in my car and it was still rich.

 

[PMD]

How high have you pushed it? I hit 1.5 but wussed out after that

 

[Brad Mayo]

I hit 1.9bar in 3rd once It lasted about a 1/2 a second and RIPPED the damn tires loose. Funny thing was that the AVCR showed 1.9bar at 3200rpms Gotta love that. I let out as soon as I saw it but would love to know what I made. I'm gonna push the hell out of it when I get it back.

 

[Flavio]

Ok guys, I tested it with the boost controller to OFF and I could boost up to 1.01bar (14.6psi). This seems okay to me, right? I really don't think the wastegate is the problem but what is???

I also increased the fuel pressure at idle (vacuum hose off) to 3.0 bar (it was 2.5 bar) because at maximum boost when the boost bouncing happens I was only at 3.7 bar fuel pressure.

Does anyone have any further suggestions?

Flavio

 

[Steve Jarvis]

I haven't had any problems with my AVC-R on the SP63 kit. I run about 45% dutycycle and hit 1.5 kg/cm2 (21.3psi) when I need to. I have the weakest spring you can get in the HKS wastegate and I have the screw on the wastegate backed off almost all the way. Make sure you have the boost controller hooked up right for an external wastegate. You will have two hoses going to the wastegate instead of one going to an actuator. The way the hoses hook up to the stepper motor is also different.

Later, Steve

 

[PMD]

The wastgate sounds good, here are a few things that you have probably checked
dip switches
boost leak
swap boost controlers with someone to test

As I recall, mine was setup (dsbc) w/ the line from the intercooler pipe, went to a t which went to the in inlet and the nipple on the side(close to the strut tower) of the wastegate. The out line went straight to the Top of the wastegate (closest to the firewall) The line that hooked up to the control unit came from the FPR line (I think)

Can't help on the fuel, I am stock

 

[Flavio]

The wastgate sounds good, here are a few things that you have probably checked
dip switches
boost leak
swap boost controlers with someone to test

As I recall, mine was setup (dsbc) w/ the line from the intercooler pipe, went to a t which went to the in inlet and the nipple on the side(close to the strut tower) of the wastegate. The out line went straight to the Top of the wastegate (closest to the firewall) The line that hooked up to the control unit came from the FPR line (I think)

Can't help on the fuel, I am stock

- Dip switches are set correctly
- No boost leak as far as we can tell, remember with nothing connected and to regulate to the wastegate boost gets as high as 2.2bar!
- Problem happens only at high boost (1.5 bar). No one I know has a similar setup to test the boost controller.
- For how I have connected my hoses see my first post. I will change the vacuum line to the BOV this Friday but I doubt this will help.

I always thought an EBC would get you a faster spoolup than an MBC but based on Brad Mayo's experience I am seriously considering switching to a manual boost controller (ball & spring type) and use the Blitz SBC just as a monitoring tool. How should I connect an MBC to the wastegate?

Flavio

 

[ttmkiv]

AMEN on the MBC!! I've got one on my T66 and its rock solid every time. Same boost, quick spool up, no worries about overboosting, and it only cost $45!! Cant beat that..

I was gonna get the bigger spring and probly will at some point but for now I just got a ball and spring manual boost controller. IT IS AWESOME! I got it to make and hold 1.4 bar in 4th and havent fooled with it since. Spool is much better too. I'll never use an EBC again. Now I can turn the boost up as far as I want.