I’m having trouble controlling boost with my new Greddy Profec B on my XS T04S single turbo kit. The way I have the Greddy Profec B hooked up is as follows:

Step motor:

HKS Racing Wastegate line to the OUT on the step motor

Charge pipe (right after the turbo) to the IN on the step motor


Controller:

Small diameter line coming from controller goes to a T on the upper intake manifold which splits the boost guage and boost controller.

Switches on the back – set for external wastegate. I tried both ways (with and without over boost)


I’m pretty sure this is hooked up right. Is it? I can not keep boost down. I keep boosting to 14+ all the time.

Let me know what you think. I really want to resolve this before I pop!

PS:Is there an adjustment on the HKS Racing Wastegate?

 

Whats the wastegate spring set to?
Your controller is hooked up fine, but it sounds to me you like you have a 14psi spring in the wastegate. You can only go as low as your wastegate spring is set to. The boost controller only tricks the wastegate into seeing less boost, thereby having the wastegate open later to make more boost.

Your hook up it fine though-

 

I have a 10psi HKS wastegate spring (Its yellow)

If I by pass the step motor, the wastegate opens at 10psi...

I tried used manual valves and they seem to work pretty good at keeping the boost down (10-12psi)

 

This is driving me nuts!!!

Im using the needle valves and they seem to work great!

But I want 2 boost settings from the seat!

Anyone have any suggestions on what it might be? Im using a 10psi wastegate spring

 

Man i dont know what to tell you.
I've installed 2 profec B's on DSM's and thats exactly how i hooked them up. They both boost perfect, and i can turn the boost all the way down to 10, the stock settings.

 

I just had the same problem. They yellow spring is the 14.7lb spring!! I had to get the white one which is the 8lb. spring. I too, have a HKS wastegate. So, the spring is indeed your problem. Good luck....

 

Here is what you need to do:

Line from the side of the wastegate goes to the OUT on the Profec.

Line from the top of the wastegate goes to a "T" Fitting with one side going to the charge pipe and the other going to the IN on the Profec.

For along time I could never get the profec B to control boost very well with a single. This method fixed that problem.

Jason

 

If you go to the HKS website, the yellow spring is for 10psi

 

Gordon,

Im going to have Dave look at it when I go for tuning. But you think the AVC-R is better? Ill see what Dave says about it.

 

Jason,

there is no fiting on the top of the HKS Racing wastegate....there is only one on the side...Is there supposed to be one on the top of it? Looks like there is a spot for one.....

 

Which boost cotroller should I get which is better than the profec B?

Apexi AVC-R

or

blitz SBC I-D

 

Anthony, go with something that definitely works. It looks like gordon said so many great things about the A'pexi. It's an awesome boost controller and it looks so ******' sweet. As for the Blitz, I just hit 16psi. I have been having so much boost creep for a few months that I can't get rid of. I'm extremely lucky that my engine is still running strong.

 

There is a spot on top of the wastegate, but you need the correct fitting for it. I thought it came with the wastegate, but I guess not.

AVC-R is a nice BC, but you wont use half the features on it.

Jason

 

Jason,

Are you using the yellow spring in the HKS racing wastegate? Are you able to get the boost down to 10psi with the boost comntroller?

You have the XS T04S kit too?

 

Here is the pic of the wastegate...Do you happen to know the size of the fitting I need?

 

I have the Profec a boost controller, on a stock TII, I notice the length and the size of the lines really effects how fast it can respond to boost pressure changes, keep the lines as short as possible also..Max

 

Ok this is straight from the horses mouth!!!

there are two connections at the wastegate...a frt chamber and a rear chamber...the frt chamber (closes to the wastegate exhaust supply) should have a line hooked to it directly from the intake...the rear chamber should go to the out on the stepping motor...the way it works is boost pressure is supplied to the wastegate diaphram...from the intake...pushing the wastegate open...the hose from the controller supplies boost pressure against the diaphram to keep it closed...the one issue is to make sure the lines have no leaks..and also what is the spring pressure at the wastegate???..hope this helps...dave@KDR

It does not expalin this in the manual!!!Im going to give it a shot!

 

Your Profec B should have come with a nipple fitting that i THINK can be used on the top of the wastegate if you dont have something that will work.

Boost creep is not a boost controller problem, but a problem with your wastegate. Boost creep is cuased when the wastegate physically can't vent enough exhuast to keep the boost level steady.

 

The Profec manual shows how its supposed to be connected- its different if you use an external w/g as opposed to an internal one. The switch settings are also different.

 

I had same problem till I got the AVC-R!!

 

I am sure the AVC-R is a very nice BC but I and many other people have used the Profec B without having any problems for years. I have used my Profec originally for nonseq stock, then a T78, and now a T60-1. I have found the Profec B to be very accurate and reliable for many years of hard driving.
With any electro-mechanical device I am sure some can and do malfunction, that can happen no matter which system you use. I am also sure some were never installed properly.
I am using a Greddy waste gate and I can tell you there is only one hose going to it and the dip switch settings on the controller are set for Actuator Type even though it is an external. I don't know why, I was told to set it this way, all I know is that this setup works. I will attach some pics to help you.

 

Here is a pic of the waste gate connection. I know the Profec B instructions show a different configuration for an external waste gate like this but for whatever reason this setup works quite well.

 

Make sure the hose to the stepper motor, infact all boost controll hoses are after the throttle body.

 

(Bringing back old topic)

I am going to be using an HKS standard wastegate with the profec B. it has 2 connections and i understand what Jason is talking about - you have to make a pressure differential.

I have 2 problems -

1) I dont know where my user manual is - would I use the actuator setting y'all are using for the Greddy WG or the external wastegate setting that is shown in the picture of the manual??

2) Where do i get the fittings for the HKS wastegate. It is a 1/8" fitting, but the one i have has apparently a different threading than what HKS uses. (I just tried one from the compressor outlet from my turbonetics turbo - maybe a metric fitting/threading instead of NPT??)

TIA,

-Nic

 

Let me know if ya still need help. The yellow Spring is 14 lb. I have found the setup to work great at higher boost.
why run 14 lb with a t04s. I run 18 all day long on the street
Troy