Boost Control Issue - need direction on next step

mblum

NOOB
OK, I'm going to try an not make this any longer than needed but want to layout my current issue and what I've done so far. My goals are to put Alky on the car this summer, but for the time being (until I get this boost under control) I'm running 93 octane + 1L of VP Octanium per 10 gal of gas.

Car and Mods:
86 GN, 91k stock short block, heads, cam, intake ect...
Racetronix 340LPH pump/sending unit with -6 &-8 Lines and Hotwire kit.
Accufab AFPR
Fresh set of Comp 980 springs.
TA-60 Turbo - .63 exh housing with a .925" ID wastegate hole.
RJC Boost Controller
PTE SLIC
TT Axis Chip with 3.5 LS1 plastic MAF with 4" CAI
TA stock style replacement headers & crossover.
RJC 3" DP, internal wastegate.
RJC 4" Single Exhaust
Stock D5 Converter (not sure if it's ever been re-stalled)
Scanmaster and Powerlogger

I purchased the car about a year ago and none of the items listed above were done to it, I've since replaced all gaskets (except rear main and head gaskets) timing chain, vacuum lines and been working through all the systems to get them up to snuff. I have no previous experience with this platform so this site and Vortex Buick have been extremely helpful along the way. I have the car running and driving and am very happy this far, all the scanmaster readings are good and it cruises down the road way better than I had ever expected considering how it ran when I first brought it home.

During all the work listed above I also installed a new HD wastegate actuator, I installed it with almost zero pre-load on the arm, maybe 1/64". Even with no preload on the arm I still get super fast spool and will build boost in the mid 20s easily at half throttle. The RJC boost controller is back off as far as possible with only about 1 thread engaged. I pulled the vacuum line off the compressor housing and used 20 PSI of shop air to test the RJC controller and HD actuator and they seem to work.

After seeing that the HD actuator was building too much boost I put the original STD wastegate actuator back on the car with 1/8" of preload, RJC controller still at the same minimum setting. On a 2nd gear pull I was able to go WOT and boost went to 15 psi quickly and from there slowly climbed to 24 where I let off. From the moment I went WOT to 24 psi was about 3 seconds in powerlogger. So it spools much slower with the STD actuator but still cannot keep boost from climbing. I also checked the STG wastegate setup with psi of shop air and it seems to function as well.

In a prefect world I would like to keep the HD actuator VS the STD during regular street driving because it makes the car much more responsive. So my question is how can I get the HD actuator to control my boost around 18-19 psi? Is my only option at this point to open up the wastegate hole? Is going to a larger turbo exh housing another option?

Any help is appreciated.
 

MikeS

Active Member
You could port the waste gate hole to bleed off more exhaust. Or, just hurry up and put alky on, then 24psi won't be enough. 93 + alky + a can of VP octanium and you should be able to hit 30psi with no knock. You aren't seeing any knock, correct?
 

mblum

NOOB
I've been logging every run to monitor boost and knock and I have not had any knock what so ever yet with the 93 + 1L of Octanium. I have Powerlogger set to start recording at anything above 2.0v on the TPS sensor. I have not changed timing from the base setting of 19 degrees in low gear and 17 in high gear that the TT Axis chip has out of the box.

I did check to make sure my knock sensor is working by holding the RPM's at 2000 and logging in PL while I tap gently on the block right next to the knock sensor with a long 3/8" extension and it quickly picked up 6 degrees of KR.

With the way the HD actuator is acting right now I'm not sure how high boost would go on a WOT run. At half throttle I can hold it at 25 psi and have a feeling it would surpass 30 if I kept putting my foot down. All of these runs were made with 1/64" of preload on the WG arm and the RJC controller backed all the way off.

I'm not sure what's reasonable, or possible with the internal wastegate setup, but I was hoping to get around 20-22 PSI with the RJC controller at it's lowest setting and then I could work my way up slowly.

My long term goals are to max out this turbo with Alky, but I really am not comfortable swinging for the fences out of the gate especially with being new to the car. I'd like to work my way up slowly so I can monitor/learn along the way and not grenade this engine. After spending the last 10 months working on the car I'm super exited to get it dialed in, it seems to be really healthy. No burning oil, good compression across all cylinders, no noticeable blow-by out the valve cover breathers.
 

dynoman

Well-Known Member
Boost creep !! You need to port the waste gate hole a little bit to bleed off more exhaust . I had the exact same problem in reverse . I couldn't build enough boost , only 24psi , so I shrunk the waste gate hole with a block off plate with a smaller hole for the puck . There should be threads on porting the waste gate hole for info , just google " turbobuick waste gate porting " .
 

dynoman

Well-Known Member
Also put your car mods in your signature . It will help us help you in the future . If viewing on your phone , turn it sideways to see the signatures .
 

Mr.Spool

Well-Known Member
OK, I'm going to try an not make this any longer than needed but want to layout my current issue and what I've done so far. My goals are to put Alky on the car this summer, but for the time being (until I get this boost under control) I'm running 93 octane + 1L of VP Octanium per 10 gal of gas.

Car and Mods:
86 GN, 91k stock short block, heads, cam, intake ect...
Racetronix 340LPH pump/sending unit with -6 &-8 Lines and Hotwire kit.
Accufab AFPR
Fresh set of Comp 980 springs.
TA-60 Turbo - .63 exh housing with a .925" ID wastegate hole.
RJC Boost Controller
PTE SLIC
TT Axis Chip with 3.5 LS1 plastic MAF with 4" CAI
TA stock style replacement headers & crossover.
RJC 3" DP, internal wastegate.
RJC 4" Single Exhaust
Stock D5 Converter (not sure if it's ever been re-stalled)
Scanmaster and Powerlogger

I purchased the car about a year ago and none of the items listed above were done to it, I've since replaced all gaskets (except rear main and head gaskets) timing chain, vacuum lines and been working through all the systems to get them up to snuff. I have no previous experience with this platform so this site and Vortex Buick have been extremely helpful along the way. I have the car running and driving and am very happy this far, all the scanmaster readings are good and it cruises down the road way better than I had ever expected considering how it ran when I first brought it home.

During all the work listed above I also installed a new HD wastegate actuator, I installed it with almost zero pre-load on the arm, maybe 1/64". Even with no preload on the arm I still get super fast spool and will build boost in the mid 20s easily at half throttle. The RJC boost controller is back off as far as possible with only about 1 thread engaged. I pulled the vacuum line off the compressor housing and used 20 PSI of shop air to test the RJC controller and HD actuator and they seem to work.

After seeing that the HD actuator was building too much boost I put the original STD wastegate actuator back on the car with 1/8" of preload, RJC controller still at the same minimum setting. On a 2nd gear pull I was able to go WOT and boost went to 15 psi quickly and from there slowly climbed to 24 where I let off. From the moment I went WOT to 24 psi was about 3 seconds in powerlogger. So it spools much slower with the STD actuator but still cannot keep boost from climbing. I also checked the STG wastegate setup with psi of shop air and it seems to function as well.

In a prefect world I would like to keep the HD actuator VS the STD during regular street driving because it makes the car much more responsive. So my question is how can I get the HD actuator to control my boost around 18-19 psi? Is my only option at this point to open up the wastegate hole? Is going to a larger turbo exh housing another option?

Any help is appreciated.
You have 2 actuators and got the boost to 24psi on one and recognized that the hd would easily go higher.
So my question is what is the problem and why do you want to be able to run 18psi with a small 60mm turbo?its no faster than a stock turbo at that point.
If you have alky and your goal is to make the 60 max out then creating boost is the way to do that.
The axis chip will automatically self correct as it works of metered air.
If you have enough injector and octane your good.
If you want 18psi you will have to port the wasegate hole to bleed off boost to get it down.
 

Mr.Spool

Well-Known Member
I've been logging every run to monitor boost and knock and I have not had any knock what so ever yet with the 93 + 1L of Octanium. I have Powerlogger set to start recording at anything above 2.0v on the TPS sensor. I have not changed timing from the base setting of 19 degrees in low gear and 17 in high gear that the TT Axis chip has out of the box.

I did check to make sure my knock sensor is working by holding the RPM's at 2000 and logging in PL while I tap gently on the block right next to the knock sensor with a long 3/8" extension and it quickly picked up 6 degrees of KR.

With the way the HD actuator is acting right now I'm not sure how high boost would go on a WOT run. At half throttle I can hold it at 25 psi and have a feeling it would surpass 30 if I kept putting my foot down. All of these runs were made with 1/64" of preload on the WG arm and the RJC controller backed all the way off.

I'm not sure what's reasonable, or possible with the internal wastegate setup, but I was hoping to get around 20-22 PSI with the RJC controller at it's lowest setting and then I could work my way up slowly.

My long term goals are to max out this turbo with Alky, but I really am not comfortable swinging for the fences out of the gate especially with being new to the car. I'd like to work my way up slowly so I can monitor/learn along the way and not grenade this engine. After spending the last 10 months working on the car I'm super exited to get it dialed in, it seems to be really healthy. No burning oil, good compression across all cylinders, no noticeable blow-by out the valve cover breathers.
Personally I think you should run the car around 26psi and keep away from the 30psi range.
This kind of tuneup will give a cushion to the motor and can be done on pump gas and a single nozzle with good pressure.
It should make a ton of torque and good horsepower for a stock motor bolt on combo and will require a built trans and run solid 11sec passes.
 

mblum

NOOB
You have 2 actuators and got the boost to 24psi on one and recognized that the hd would easily go higher.
So my question is what is the problem and why do you want to be able to run 18psi with a small 60mm turbo?its no faster than a stock turbo at that point.
If you have alky and your goal is to make the 60 max out then creating boost is the way to do that.
The axis chip will automatically self correct as it works of metered air.
If you have enough injector and octane your good.
If you want 18psi you will have to port the wasegate hole to bleed off boost to get it down.
Forgot to mention I have 60lb injectors from TT.

I don't necessarily want to run 18 PSI, I just wasn't sure of the "adjustable range" the RJC MBC.

I guess my problem is I was able to get the STD wastegate down to 24 psi but that was with me lifting my foot to avoid higher boost. It made the 24 psi and was still climbing before the engine got to the shift point in 2nd gear so I let off the throttle. If the 24 psi was stable during the entire WOT run I would be just fine with that as a starting point, but it was still climbing.

So it looks like I have a boost creep issue and want to make sure I address it in the correct way. I'd like to stick with the HD actuator and will port the wastegate hole if that is my best approach.

I guess part of my question, and this is from my lack of experience with this engine, is if my end goal is 26 psi on Alky, what adjustable range should I be shooting for when using the manual boost controller? Or is my understanding of the MBC all wrong?

Example: If the RJC MBC at it's minimum setting gives me 22 psi, I could still increase the boost to 26 PSI by adjusting the boost controller and still have head room above that if I needed? This is the approach I guess I was shooting for, but maybe that's not how things work.

Thanks for the patience with the new guy.....
 

mblum

NOOB
Personally I think you should run the car around 26psi and keep away from the 30psi range.
This kind of tuneup will give a cushion to the motor and can be done on pump gas and a single nozzle with good pressure.
It should make a ton of torque and good horsepower for a stock motor bolt on combo and will require a built trans and run solid 11sec passes.
A rebuilt trans from Dave Husek with matching LU converter is next on the list, spoke to him recently and hope to have it off to him shortly.
 

turbocamino1

turboholic
On my 6266 (from Bison) i worked the backside of the wastegate hole. The exh being dumped is coming from a certain direction,towards the gate hole. Contours that in a canoe ,gully ,type fashion . Just be careful not to oblong the puck mating surface at all. On mine,there was a lot of material,almost a wall, on the backside of the gate hole.
 

Mr.Spool

Well-Known Member
A rebuilt trans from Dave Husek with matching LU converter is next on the list, spoke to him recently and hope to have it off to him shortly.
Yeah I wouldn't run it hard till you get that done.
I dont even tune on the cars above 20psi anyone without a built trans.
Your rjc valve is really like a bleed off.
Applying a certain pressure on the gate which has a built in spring pressure on its it's own.
 

mblum

NOOB
On my 6266 (from Bison) i worked the backside of the wastegate hole. The exh being dumped is coming from a certain direction,towards the gate hole. Contours that in a canoe ,gully ,type fashion . Just be careful not to oblong the puck mating surface at all. On mine,there was a lot of material,almost a wall, on the backside of the gate hole.
I remember looking at my wastegate hole and noticing that there is a large fillet on the back side (inside) of the exhaust housing. Is this the area your talking about? I get the concept of smooth air flow and avoiding turbulence from sharp corners. I will look at this area again before I enlarge my WG hole.
 

turbocamino1

turboholic
I remember looking at my wastegate hole and noticing that there is a large fillet on the back side (inside) of the exhaust housing. Is this the area your talking about? I get the concept of smooth air flow and avoiding turbulence from sharp corners. I will look at this area again before I enlarge my WG hole.
Yes.exactly.,i removed that whole ledge. Honestly ,i never have tried to regulate to low boost ..she stays around 28-30.
 

Pronto

Chaos is a ladder.
You can see how well the puck is sealing by the carbon mark or you can apply some grease to it to mark the edge of the puck. You can also see how well the hole lines up with the puck. You can carefully machine it open but don't go too close to the edge. Get that alky, trans and torque converter in there and let that turbo breath. You're just tickling it at 18.
 

TurboTGuy

Gray Beard Member
Be careful!

We hogged mine out too big the first time around. Thank goodness RJC sells a block off plate you can customize........But it's a PIA R&I'ing the down pipe more than once and it's not the "best fix"...

I'm running a different turbo now with my new combo, so the old problems were eliminated, but i don't feel this new turbo , DBB CEA 6466 hits near as hard as my old one.

I might just go back to the DBB CEA 6765 and block off plate and see what happens.
 

TurboTGuy

Gray Beard Member
OH! And additionally, you need the right boost controller, one that looks good and performs flawlessly.

And if you stick with a MBC, no one does a better controller than a Hallman Pro MBC, NO ONE!

Others may vary in their opinions, but I am dead nuts on.

Period.

$99 on Amazon. (today)
 
Last edited:

mblum

NOOB
OH! And additionally, you need the right boost controller, one that looks good and performs flawlessly.

And if you stick with a MBC, no one does a better controller than a Hallman Pro MBC, NO ONE!

Others may vary in their opinions, but I am dead nuts on.

Period.

$99 on Amazon. (today)
So out much should I remove from the wastegate hole to start with? I'm wanting to stick with the HD actuator if at all possible. .030" or more/less? Its at .925" now so I was thinking taking it up to .960" or so and trying it there.

Also school me on the differences between the manual boost controllers, I'm always willing to learn.
 

TTA308

Active Member
So out much should I remove from the wastegate hole to start with? I'm wanting to stick with the HD actuator if at all possible. .030" or more/less? Its at .925" now so I was thinking taking it up to .960" or so and trying it there.

Also school me on the differences between the manual boost controllers, I'm always willing to learn.
You can go up to 1" as long as you have 1/8" puck covering all around, the inside is more important..
EarlBrown has a very good boost controller.
 

Mr.Spool

Well-Known Member
but i don't feel this new turbo , DBB CEA 6466 hits near as hard as my old one.

I might just go back to the DBB CEA 6765 and block off plate and see what happens.
Def something wrong
Any heads cam combo should see a 64bb lite up in a blink of an eye.
Even if your light on stall.
If had them literally idle in boost on motors with compression and heads cam.
Time to check things.
PM me if you want to discuss
Always willing to help
 

Mr.Spool

Well-Known Member
Turbosmart electronic boost controller with co2 is the next step for those that want to control precisely what the boost is doing.
 
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