RJC Boost Controller...and my pesky boost spike issue

[meanchicken]

Installed one....Wow…it works….a little to good.

Before I installed it, I had my waste gate actuator set at 16 lbs.

I installed this bugger and backed off the WG actuator to close to the stock setting per the instructions (probably between 1/8 and ¼ inch from the WG puck arm pin)….but not close enough evidently.

This morning I tipped into WOT while watching the boost gauge. It climbed quickly….to 20lbs, so I pulled back out. I checked the ScanMaster and it only showed about 2.8 degrees of KR at WOT which isn’t terrible, but it could have gotten worse had I stayed in it. O2's in the normal range of 780-820.

Was able to get 15lbs of boost at just shy of ¾ throttle….so I lengthned the WG Actuator another couple turns and did some more testing.

The behavior I see on my boost gauge, is when I go WOT, the needle jumps straight to 18-19 lbs and then drops back to 14 before drifting back up to 16lbs and then stabilizes. It did all this before I installed the RJC Boost controller...that initial ramp of boost just happens much faster now.
But it's not the controller that is causing it.

During that initial boost spike, I get the KR.
If I slowly roll into the throttle, the spike is more of a mild drift and does not go as high before dropping back down.

Any advice, thoughts, can I really tune this RJC controller buy turning the actuator end in and out? How much?

What else should I be looking for that might be causing that inital WOT boost spike?

Thanks!
Tim

[GNVYUS 1]

1st, I've found from noodling with manual boost controllers that keeping the adjustable rod tighter and letting out the manual helped spool up. I generally let out the manual's screw until I know it's not doing anything, then screw it in to get a few lbs of boost to put pressure on the spring and adjust the wastegate arm from then on for more boost.

Anyways, it spikes now because the factory solenoid bleeds off pressure so it never hits as hard unlike the manuals and need to bleed off that pressure all of a sudden.

The cure is the take off the downpipe and open up the wastegate hole on the turbo's exhaust housing. There are a bunch of tech tips on it but stay inside the carbon ring around the hole and use a shop vac to suck out the debris. Smooth out the inside of the housing and then watch the spikes disappear with maybe a 1psi at most.

[meanchicken]

Thanks.
I'll give the controller adjustment tips a shot.

When backing the nut out on the controller....how far is too far?
Just wondering if there is a minimum thread engagement before I start leaking at the controller.....

The exhaust elbow porting has been suggested to me before. In fact one of these nice gents has offered to trade me his ported elbow for my unported one....

[ngnowner]

Hey mean chicken just went through this, I was getting about 3-4lbs of boost creep on the stock setup. So I bought the RJC controller and ported the wastegate hole with a dremel tool....problem solved. There are good posts here on how to do it, pretty simple. Hardest part is getting the bolts out of the exhaust housing without snapping 'em off. Now she shoots right to 17lbs and stays there all the way through third. That is the lowest setting I could get the RJC controller too. I cranked the top screw all the way out, turned it in 3/4 and locked it down. 17lbs is a little higher than I wanted to be to start, wastegate rod set to stock length/preload. I haven't tried tuning the boost controller but I would imagine I could compress the spring a little more to give less preload. But the boost hits hard now....it was a little scary at first but it's a blast to drive.....kind of like an e-ticket ride at disney. LOL

[mcasteel2112]

Originally Posted by ngnowner

Hardest part is getting the bolts out of the exhaust housing without snapping 'em off.

I been working on a friends car installing DP (see home made DP thread)...well 20 yr old car with elbow never removed and I snapped off a bolt flush...PITA but I got it drilled and retapped after a few time outs.

So my advice Tim, when you get ready to remove that elbow is to hold your breath...lol na prolly stick a little heat on at least the top 3 bolts then quick nudge on the tight side then back em out...of course I always tighten old bolts first then loosen

I sold that real pretty elbow I ported for ya..lol but i got another sitting here ready for clean up...lemme know

And quick note: the porting thats being mentioned is the wastegate hole, not the elbow itself although that does help with flow

[ngnowner]

So my advice Tim, when you get ready to remove that elbow is to hold your breath...lol na prolly stick a little heat on at least the top 3 bolts then quick nudge on the tight side then back em out...of course I always tighten old bolts first then loosen


+1....great advise

[mcasteel2112]

Nothing worse then trying to break a bolt free, then feeling that old soft spot knowing ...well ya broke it free alright

[Quick6'n'-K.C.]

I would check to see if the wastegate doesnt have a hole in the diaphragm, also loosen up the wastegate rod to lower the boost. I noticed in your sig, you have a adj wastegate, is it a heavy duty wastegate????

Start with the basics, it shouldnt spike.

Did you buy the RJC valve from RJC?

BW

[GNVYUS 1]

Like mentioned, the ported elbow won't fix this problem, porting the turbo's exhaust housing is the needed porting.

Dremel and a shop vacuum = No more boost spikes

[rodman99999]

Did anyone mention shooting little PB Blaster/kroil/Rust Buster or some other penetrating liquid on those four elbow bolts a couple times, a few hours before you give 'em He!!? Might save you some headaches later. Yeah- Port the wastegate hole. I never had creep, until I installed the RJC. Never had it again after I ported the housing. But then- That spike may represent a different issue.

[Quick6'n'-K.C.]

Originally Posted by DR.BOOSTER

Like mentioned, the ported elbow won't fix this problem, porting the turbo's exhaust housing is the needed porting.

Dremel and a shop vacuum = No more boost spikes

I was going to quote your first post, but again, too much wastegate spring pressure will always equate a boost spike..

Its all in fun working on these cars, its a stock turbo, so its not the puck hole that is the problem....
I really think, start with the basics, rjc valve from rjc? is it a heavy duty waste gate by accident? Is the diaphragm leaking? no leaks on the new 7/32 hoses for the valve?

Just trying to help, i try to help....

BW

[rodman99999]

OHHH- Stock turbo? I think Quick6 is right in it not being the wastegate hole. Aren't you supposed to adjust the actuator rod so it just has a slight shake to it(just barely holding the puck against the housing)?

[meanchicken]

Thanks, guys.
Great advice.

Originally Posted by ngnowner

So my advice Tim, when you get ready to remove that elbow is to hold your breath...lol na prolly stick a little heat on at least the top 3 bolts then quick nudge on the tight side then back em out...of course I always tighten old bolts first then loosen

+1....great advise

Yup...I need to go buy me a new "Fire wrench" (a.k.a. torch)
The nudge to the tight side is a great idea. Thanks mcasteel!

I can relate to busting bolts....When I was removing my driver side header a couple months back, I busted one of the cross over pipe bolts in the header, so I had Lou drill it out for me when he was welding up the crack at the #5 primary.

When I was prepping the bottom end of my ZZ502, I opened up the oil pump to prime it a little by dumping some EOS into it, when I was putting the cover back on, I over torqued and snapped one of them cover bolts so had to take the pump out and go get the bolt removed....

Originally Posted by ngnowner

Hey mean chicken just went through this, I was getting about 3-4lbs of boost creep on the stock setup. So I bought the RJC controller and ported the wastegate hole with a dremel tool....problem solved. There are good posts here on how to do it, pretty simple. Hardest part is getting the bolts out of the exhaust housing without snapping 'em off. Now she shoots right to 17lbs and stays there all the way through third. That is the lowest setting I could get the RJC controller too. I cranked the top screw all the way out, turned it in 3/4 and locked it down. 17lbs is a little higher than I wanted to be to start, wastegate rod set to stock length/preload. I haven't tried tuning the boost controller but I would imagine I could compress the spring a little more to give less preload. But the boost hits hard now....it was a little scary at first but it's a blast to drive.....kind of like an e-ticket ride at disney. LOL

Thanks...good stuff!

Originally Posted by Quick6'n'-K.C.

I would check to see if the wastegate doesnt have a hole in the diaphragm, also loosen up the wastegate rod to lower the boost. I noticed in your sig, you have a adj wastegate, is it a heavy duty wastegate????

Start with the basics, it shouldnt spike.

Did you buy the RJC valve from RJC?

BW

I dunno if it's a HD adj WG actuator. It looks like the OEM piece.....but with an adjustable arm. I bought it from mcasteele....Hey Mike....is this thing a HD actuator?

Yup, it's a new RJC controller straight from RJC.

Originally Posted by rodman99999

Did anyone mention shooting little PB Blaster/kroil/Rust Buster or some other penetrating liquid on those four elbow bolts a couple times, a few hours before you give 'em He!!? Might save you some headaches later. Yeah- Port the wastegate hole. I never had creep, until I installed the RJC. Never had it again after I ported the housing. But then- That spike may represent a different issue.

I've already started this process....I'm going to be doing it for days rather than hours tho'

I squirted a little penetrant on each elbow bolt and also on the down pipe bolts. I'll let it sink in for a day and go back and soak it again tomorrow and probably once or twice more this week. If I get a chance next weekend, I'll pull the elbow and port the WG hole.

I don't think I'll port the whole housing just yet....It's my understanding doing that will improve the flow to the point of adding 1-2 more lbs of boost...I'll wait until I get alky on this car before I start trying to add more boost. Cali's 91 octane just aint very boost friendly....

Thanks again guys!

Oh...are there gaskets between the turbo and exhaust elbow and between the exhaust elbow and DP?

[mcasteel2112]

Tim,

Ya know I never checked the numbers stamped on it but I would be its not a H/D

after sleeping on what happend to me last night, IM drawing conclusion that I had a major spike last night and boost went from what i launched at to 25#s in one sweep. Although I have my boost set at 24# max, it shot with nothing inbetween and about killed me

[mcasteel2112]

double post, sticky send button

[rpk250]

are you using an stock actuator or an HD acuator

[meanchicken]

Originally Posted by rpk250

are you using an stock actuator or an HD acuator

It's an adjustable actuator, and as far as I know, it's not heavy duty.

I might throw my stock (non adjustable) one back on as a quick check to see if the adj actuator is contributing in any way.

Thanks!
Tim