Boost falling off

[vrracing]

Relevant mods

90 S5 Vert.
JDM Tii
Pineapple Racing street port
BNR Stage1 turbo
Bonez cat-forward. Corksport cat-back with Vibrant UltraQuiet resonator.
RTek Stage2
720/1000cc injectors
Zeitronix w/b
HKS EVC Black Edition

With the EVC off, we were seeing a max of about 4.5psi so I'm assuming the wastegate spring is about 4.5pounds. We set the EVC to 50% and we were expecting about 7psi max (4.5 + (50% * 4.5)) but it went to ten; which was fine.

As you can see in the Zeitronix chart, boost is maxing out at ~10psi at 4700RPM and drops off gently from there.

http://i366.photobucket.com/albums/oo104/vrracing/Turbo10.png

We are using Aaron Cake's rule of thumb AFR tuning targets

0-4 PSI: 12-12.5
4-8 PSI: high 11s
8 - 15 PSI: mid to low 11s
16 PSI +: high 10s

but obviously the 1000cc secondaries still need to be pulled back some. IIRC we are pulling them back about 3% above 4500RPM.

Is the fact that we're getting too rich after 4500RPM what's causing the boost to fall off or is the wastegate spring at fault?

Thanks, appreciate any guidance yall have.

[TitaniumTT]

Aaron Cakes "rule of thumb" AFR's are stupidly rich. I wouldn't follow anything of what he says.

More important, what are your timing numbers like?

The boost will fall off in the higher revs... this is just fact.

[RETed]

1) Get an EGT gauge
2) Learn how to tune with EGT
3) You're running too rich - too much fuel suppresses boost
4) Stop listening to Cake's bullshit


-Ted

[Prodigy]

1) Get an EGT gauge
2) Learn how to tune with EGT
3) You're running too rich - too much fuel suppresses boost
4) Stop listening to Cake's/BDC's/HC's/Mar3's bullshit


-Ted


QFT!!!!

:D

So instead of tunging using target AFR's you are sugguesting using EGT's...?

I thought (assumed) it was more accurate and "safer" to tune via AFR's not EGTs

input from both You Ted and Bryan would be great, as I am trying to increase my knowledge to when I decide to start trying to tune..


J

[TitaniumTT]

1) Get an EGT gauge
2) Learn how to tune with EGT
3) You're running too rich - too much fuel suppresses boost
4) Stop listening to Cake's bullshit

-Ted

QFT!!!!

:D

So instead of tunging using target AFR's you are sugguesting using EGT's...?

I thought (assumed) it was more accurate and "safer" to tune via AFR's not EGTs

input from both You Ted and Bryan :squint:

would be great, as I am trying to increase my knowledge to when I decide to start trying to tune..


J

EGT's will help you dial in the timing. For the people that have been doing it a long time, they can get damn close to target AFR's with EGT's

[vrracing]

Wow! That's a lot of vitriol thrown Aaron's way.

I should have explained our goals and constraints. The car is my 21 year old's DD and all it needs to do is provide him fun, entertaining transportation until he graduates college. If it blows up and burns to the ground the second he receives his diploma then it has served its purpose.

It will never be raced but we don't want it so neutered as to simulate a soulless but infinitely reliable Corolla. Since we rebuilt the PoS Tii we got from TigerJapanese 3 years ago the car has run nicely at stock boost with an SAFC to fatten up the top end of the range.

Then in Oct'10 the turbo died and I had BNR rebuild it and had him do a Stage1 since it was just a bit more money.

Then in July'11 the SAFC died so I got the RTek 2 upgrade (from a 1.8) installed as it was cheaper than buying another SAFC and had more tuning headroom.

Over the winter I took the HKS EVC out of my 17 year olds MR2turbo and just ran it off the Tial's 12# spring since he doesnt need any more than that much boost. I believe that the FC's boost solenoid was lame because we were only seeing about 4.5 lbs of boost and when the ignition was on that solenoid would often buzz. So we put the HKS in the FC a couple of weeks ago and just this weekend turned it on and did a little street tuning; starting fat and leaning it slowly.

So we are not looking to tune it within an inch of its life, not looking to drag race it, not looking to spend any money, not looking to search for a pro tuner who knows rotaries and is willing to touch an RTek. Just want to find a reasonably reliable, reasonably fuel efficient, reasonably performant DIY street tune that will get him to and from school and will pass TX emissions and inspections.

Given that the stock turbo is frequently taken to 12psi I figured we'd set Mode A to 10PSI for daily driving and Mode B to 14psi as Brian@BNR said the Stage 1 was good to 1Bar.

On the RTek we are using the default Fuel Correction Map configuration. I have neither the skill to mess with rotary ignition timing nor the interest in learning. It is hard enough to find rules of thumb like Aaron's AFR and I have never seen a HowTo for tuning a rotary with EGTs and timing. And unfortunately the price of being a little tiny bit wrong is a blown engine with destroyed rotor housings.

So my take-aways from the replies are:


Aaron's AFRs are conservatively rich but no one has an alternative recommendation (except for buying EGT gear)
We are running richer than Aaron's already rich #s and that will impede our ability to boost
That richness may be why we max out at 10psi whether at 50% or 75% on the HKS.


Cool. We'll lean it out some more and see if that removes the 10psi ceiling.

Thanks,

Jim

[rxspeed7]

For a relativley stock turbo and motor, you can be in the mid to high 11's at 10psi, even 12 flat.

There will always be some taper in boost with the stock turbo, it just can't hang in the upper rpms.

[TitaniumTT]

:rofl: I run 11.7 @ 17psi... and @ 1br I'm running about 12 flat. Then again... my ECU is a little more exact and responsive than an Rpuke.

Cake really shouldn't be listened to when it comes to certain/most things alot of people with violently disagree with. Why some people have their rantings taken as gospel and looked at as rules of thumb is beyond me.

Seriously though, is there anyway you can post up a timing map? I'm willing to bet there is a TON more power to be had out of your setup.

The thing that alot of people don't realize is that you can be so far into the so-called "safe-zone" that it actually becomes dangerous and will pop your engine.....

I refer you once again to 13B-RE Nova who had a thread in the single turbo section entitled.... why did my engine blow.

Basically he was running low to 10flat AFR's @ 21psi and 6*'s of timing making a whopping, earth rotating 427rwhp on a GT42 or 45....... oh, and it was HBP'ed.... anyone care to take a guess why he popped his engine and why hc and bdc are totally and completely WRONG and stupid for suggesting that all he needed was colder plugs?

[rxspeed7]

^ most def, timing too retarded and afr's too rich can cause just a many probs as lean and way advance. def try to pull the leading and trailing maps off the rtek and post them up please!

[vrracing]

We havent touched the timing maps at all.

I've been using the Zeitronix for logging boost, TPS and AFR but I believe I can log the boost, RPM, and the timing via the RTek PocketLogger. Havent played with that at all.

I'll try saving the configuration and see if the file is sync'd to the PC. That would have the stock timing maps in it. I know ARGHX tried getting the timing maps but it is tedious and so from what I can tell never happened.

We'll give it a go later this week or this weekend.

[Pete_89T2]

We havent touched the timing maps at all.

I've been using the Zeitronix for logging boost, TPS and AFR but I believe I can log the boost, RPM, and the timing via the RTek PocketLogger. Havent played with that at all.

I'll try saving the configuration and see if the file is sync'd to the PC. That would have the stock timing maps in it. I know ARGHX tried getting the timing maps but it is tedious and so from what I can tell never happened.

We'll give it a go later this week or this weekend.

The Rtek Pocketlogger SW can log basically everything that the stock ECU uses as an input sensor, (i.e., MAP, intake temps, TPS, etc.) plus it has a spare input line that can be configured to log a wideband O2 sensor (0~5V, that you supply).

WRT timing maps, the Rtek simply lets you directly overwrite whatever data is stored in the stock maps (in degrees). In other words, be very careful here because the consequences of a fat finger error can be severe, especially if you didn't keep track of the stock settings before making changes.

[vrracing]

The kid returned from class so we went out and did a quick third gear pull. It is currently 67 degrees and 60% humidity and we are at 600 feet elevation.

The RTek log display program is not especially impressive so I took four screen shots at different points so you could see the numbers. The app ignores any attempt to change the color of timing series so I left them in separate bands. Probably makes it easier to see anyways.

http://i366.photobucket.com/albums/oo104/vrracing/Timing1.png

http://i366.photobucket.com/albums/oo104/vrracing/Timing2.png

http://i366.photobucket.com/albums/oo104/vrracing/Timing3.png

http://i366.photobucket.com/albums/oo104/vrracing/Timing4.png

Again, these are all stock timing values.

Thx

[vrracing]

In other words, be very careful here because the consequences of a fat finger error can be severe, especially if you didn't keep track of the stock settings before making changes.

According to turbo2ltr on the other site "With the Stage 2.0, to go back to nearly completely stock, you can initialize the ECU from within the software and, poof, you are stock again."

Course hopefully that's before :puke:

[TitaniumTT]

I hate to say it, but she really needs to be put on the dyno. Those afrs are way to rich, and the timing seems to be a little weak. Not to mention the split seems like it needs to be tightened way up too. We generally run 10* split in boost, not 20, if im reading that right.

If you're wanting to only mess with the fuel, set it for 12.5 @ 0 psi, 12 by say 7 psi, and nothing richer than 11.7

[vrracing]

Yeah I read the thread on the single turbo forum you mentioned and I dont think they like you very much. :nopity:

Both Brian Cain (BDC Motorsports) and Steve Kan are in DFW so if the kid wants to spend the $400 he's welcome to do the dyno thing! It's only a 3 hour drive and he can go to In-N-Out for lunch. Course he'd have to call and make sure they'd be willing to contaminate themselves by touching an RTek.

We'll lean it out and see what happens. The preset is for 720/720 and we have 720/1000s and we added fuel across the map above 6psi just to be sure we weren't lean.

We'll get the AFRs in line and then we'll come back and ask about timing.

[TitaniumTT]

DO NOT UNDER ANY CIRCUMSTANCES TAKE YOUR CAR TO BDC.

What you're not reading in that thread are all the posts I made that contradict what rx7clubs PAYING vendors say and on top prove them wrong. They were all deleted.

There is an actual shop in PA called Speed1. The website is in my link. The owner recruited me from well over 100 miles away and three states, found me housing and employed me to run the. Dyno and do the tuning. An actual established shop, not two different people who don't own a dyno and need to travel to find work.

If you'd like, I can link you to a few threads in the lounge that specifically discuss bdc and his mountain of failures

[RETed]

If you're satisfied with what you've got and what you've attained, then you can stop reading here.

If you want to optimize your set-up and get the best power for all the money that you spent, keep reading...

Sure, the car runs, and it doesn't blow up...
Good enough?
For most of us, it's not...especially when you have the capability to adjust parameters on engine control (i.e. fuel delivery and ignition spark timing).
You have full control over those things, but yet you don't want to optimize it?
That just doesn't make any sense - you might as well get a reprogrammed stock ECU set for your needs and call it a night.

Widebands are easy to use for your average Joe Schmoe cause it's just a single number.
It's easy to tell someone to shoot for a target AFR #...
Is this optimized?
Not necessarily so...
Widebands needs to be calibrated.
Widebands "wear out" and fail.
Widebands can be contaminated by bad gas or even by some gasoline additives.
Most wideband useful lives are around 100 - 150 hours or use?
That's a pretty short life compared to a K-type thermocouple...

Like TTT said, the car should be run on a dyno...
It allows for a controlled environment to see what kinda of power the engine is making.
At the same time, you need to watch all your gauges to "dial them in" so you know what is OK and what is DANGER.
You need to understand that one engine might make best power at 11.7, but another engine would make best power at 11.2.
Not only does this affect widebands, but it does apply to EGT gauges too.
When widebands start to fail, it gets out of calibration and reacts slower and slower.

Sure, EGT gauges do not react as quickly as widebands, but EGT tells you a lot more and a lot more reliability.
K-type thermocouples last a lot longer.
Once you know what the sweet spot of the EGT that makes the best power on the dyno, then you can adjust ignition timing too.
Leave the EGT gauge in the car, and you have constant monitoring of your engine running - any problems that affect engine performance will show up on the EGT gauge, once you get used to what the EGT gauge should be showing.
If you can tune with an EGT gauge, you don't need a wideband.
The only thing that can affect (i.e. damage) an EGT probe is flying debris - in this case, you've got bigger problems than worry about the EGT probe at this point.

You should also be "reading your spark plugs."
I bet they are pretty black and sooty.


-Ted

[vrracing]

Yeah, in my very first post I noted that the AFRs were George Soros rich. So I'm not sure I understand why that is attracting so much attention. TTT wanted to see the timing map so I pulled those charts for him. But we haven't had a chance to lean out the fuel map yet.

I don't look at "optimize" as binary. As my production engineering prof emphasized to us "perfect tolerances are infinitely expensive." I run software development orgs and we discuss product investments in terms of "marginal rate of return". Basically you reach a point where each additional dollar of investment returns less and less value.

I'm familiar with EGT monitoring as we monitored it on his sprint car using an Aimsports system and would adjust jets and send the logs back to our engine builder. And like W/B O2 sensors they can degrade with catastrophic effects (http://www.zeitronix.com/installation/EGTinstallation.shtml).

My sense from the discussion so far is that the tuning knobs we can turn in decreasing order of margin rate of return are:


AFR tuning leaner than AC's rule of thumb numbers. We are way outside the ballpark now and while we won't maximum any parameter it will make the car more fun and reliable. And 10psi of boost at 10AFR is a lot more fun than 4.5psi.
Once the AFRs are in the ball park we can gen another set of charts and we might see that timing adjustments may be warranted based on TTT's expertise and experience.
Get an EGT for $80. This would have little value without professional tuning and hours of dyno time.
Spend $400+ on professional tuning and dyno time.


What I dont understand is what does the marginal rate of return curve look like as you traverse these investments. For example, if we do step 1 and get 250rwhp if we spend the $500 for steps 3 and 4 will we end up at 255rwh or 350rwhp and 30mpg city?

We'll get the AFRs in line and then post more charts.

Thx all.

[Pete_89T2]

I can give you one sample point to judge return on investment on a similar setup. Currently running a stock S5 13BT with about 50K miles on the block. No porting or internal mods to the engine. I'm running a BNR Stage 1 turbo, with 720cc Bosch FI's in all 4 holes, and a Supra TT fuel pump. Stock ECU with Rtek 2.x mod for control. Intake is stock with a K&N filter, and when I got it dyno tuned last winter, the exhaust was a Bonez DP into the stock main cat, into a Borla catback.

Took it to Dave at Speed1 (Brian's boss) for dyno tuning. Going in with the default Rtek settings (other than checking the box for 720's FIs in all 4 holes), my car put down about 189rwhp, but boost was maxing out at just under 6 psi -- Dave found this was due to a restrictive main cat. After Dave's tuning magic, which cost just under $200, I left with about 210 rwhp. Not bad for boost limited to <6psi!

Over the summer, I managed to get historic plates on the car and yanked the main cat & Borla DP and replaced them with the Racing Beat DP & pre-silencer combo. Still using the stock EBC solenoid as controlled by the ECU which now nets me a very consistent 8~9 psi boost all the way up to redline. Haven't brought it back to Dave yet for dyno tuning, but the butt dyno tells me the improvement is significant -- need to make an appointment to get it dialed in.

[sa22c]

Yeah, in my very first post I noted that the AFRs were George Soros rich. So I'm not sure I understand why that is attracting so much attention. TTT wanted to see the timing map so I pulled those charts for him. But we haven't had a chance to lean out the fuel map yet.

I don't look at "optimize" as binary. As my production engineering prof emphasized to us "perfect tolerances are infinitely expensive." I run software development orgs and we discuss product investments in terms of "marginal rate of return". Basically you reach a point where each additional dollar of investment returns less and less value.

I'm familiar with EGT monitoring as we monitored it on his sprint car using an Aimsports system and would adjust jets and send the logs back to our engine builder. And like W/B O2 sensors they can degrade with catastrophic effects (http://www.zeitronix.com/installation/EGTinstallation.shtml).

My sense from the discussion so far is that the tuning knobs we can turn in decreasing order of margin rate of return are:


AFR tuning leaner than AC's rule of thumb numbers. We are way outside the ballpark now and while we won't maximum any parameter it will make the car more fun and reliable. And 10psi of boost at 10AFR is a lot more fun than 4.5psi.
Once the AFRs are in the ball park we can gen another set of charts and we might see that timing adjustments may be warranted based on TTT's expertise and experience.
Get an EGT for $80. This would have little value without professional tuning and hours of dyno time.
Spend $400+ on professional tuning and dyno time.


What I dont understand is what does the marginal rate of return curve look like as you traverse these investments. For example, if we do step 1 and get 250rwhp if we spend the $500 for steps 3 and 4 will we end up at 255rwh or 350rwhp and 30mpg city?

We'll get the AFRs in line and then post more charts.

Thx all.

blah blah blah

If you set the car up right, a V-trim compressor on a standard series 5 rear end with appropriate fueling is good for 22+psi in the midrange (I know a guy who ran 25psi).

People will cry and moan it can't be done, but mid-high 10 second quarter miles at mid to high 120s to low 130s are possible in a 79-85 RX-7. In the heaver FC3S low 11s (like 11.0) is possible with a turbo that small. People have been doing it for probably 10 years.

Whats even better is people have been doing it since the mid 2000s without race fuel.

0.78 lambda is a good figure to shoot for. Frankly I'm an graduate engineer (with honours) also. I work in research and development. Most of the muppets on the internet, its not even worth reading their posts. I'm yet to lose an engine from anything but old age and I have a car that can be daily driven and is in the 11 second bracket now. I've probably put 60k miles on my car since I've owned it.

[TitaniumTT]

Yeah, in my very first post I noted that the AFRs were George Soros rich. So I'm not sure I understand why that is attracting so much attention. TTT wanted to see the timing map so I pulled those charts for him. But we haven't had a chance to lean out the fuel map yet.

I don't look at "optimize" as binary. As my production engineering prof emphasized to us "perfect tolerances are infinitely expensive." I run software development orgs and we discuss product investments in terms of "marginal rate of return". Basically you reach a point where each additional dollar of investment returns less and less value.

In this case though, it's an ongoing loss. Everytime you drive the car your burning more fuel thatn need be, and fouling plugs quicker than need be

I'm familiar with EGT monitoring as we monitored it on his sprint car using an Aimsports system and would adjust jets and send the logs back to our engine builder. And like W/B O2 sensors they can degrade with catastrophic effects (http://www.zeitronix.com/installation/EGTinstallation.shtml).

My sense from the discussion so far is that the tuning knobs we can turn in decreasing order of margin rate of return are:


AFR tuning leaner than AC's rule of thumb numbers. We are way outside the ballpark now and while we won't maximum any parameter it will make the car more fun and reliable. And 10psi of boost at 10AFR is a lot more fun than 4.5psi.

Leaning it out will net more power though.


Once the AFRs are in the ball park we can gen another set of charts and we might see that timing adjustments may be warranted based on TTT's expertise and experience.

Be glad to help.

Get an EGT for $80. This would have little value without professional tuning and hours of dyno time.[/quote]

Which EGT gauge? I have a feeling that it's not going to react nearly as quickly as it should.

Spend $400+ on professional tuning and dyno time.


That is excessive by our billing standards

What I dont understand is what does the marginal rate of return curve look like as you traverse these investments. For example, if we do step 1 and get 250rwhp if we spend the $500 for steps 3 and 4 will we end up at 255rwh or 350rwhp and 30mpg city?

We'll get the AFRs in line and then post more charts.

Thx all.

Like I said.... it will continue to cost in more frequent oil changes, more gas burned, more fouled plugs and power lost, excessive carbon buildup etc etce etc.

I can give you one sample point to judge return on investment on a similar setup. Currently running a stock S5 13BT with about 50K miles on the block. No porting or internal mods to the engine. I'm running a BNR Stage 1 turbo, with 720cc Bosch FI's in all 4 holes, and a Supra TT fuel pump. Stock ECU with Rtek 2.x mod for control. Intake is stock with a K&N filter, and when I got it dyno tuned last winter, the exhaust was a Bonez DP into the stock main cat, into a Borla catback.

Took it to Dave at Speed1 (Brian's boss) for dyno tuning. Going in with the default Rtek settings (other than checking the box for 720's FIs in all 4 holes), my car put down about 189rwhp, but boost was maxing out at just under 6 psi -- Dave found this was due to a restrictive main cat. After Dave's tuning magic, which cost just under $200, I left with about 210 rwhp. Not bad for boost limited to <6psi!

Over the summer, I managed to get historic plates on the car and yanked the main cat & Borla DP and replaced them with the Racing Beat DP & pre-silencer combo. Still using the stock EBC solenoid as controlled by the ECU which now nets me a very consistent 8~9 psi boost all the way up to redline. Haven't brought it back to Dave yet for dyno tuning, but the butt dyno tells me the improvement is significant -- need to make an appointment to get it dialed in.

That's what I like to hear! When are you bringing that thing back up here?

blah blah blah

If you set the car up right, a V-trim compressor on a standard series 5 rear end with appropriate fueling is good for 22+psi in the midrange (I know a guy who ran 25psi).

People will cry and moan it can't be done, but mid-high 10 second quarter miles at mid to high 120s to low 130s are possible in a 79-85 RX-7. In the heaver FC3S low 11s (like 11.0) is possible with a turbo that small. People have been doing it for probably 10 years.

Whats even better is people have been doing it since the mid 2000s without race fuel.

0.78 lambda is a good figure to shoot for. Frankly I'm an graduate engineer (with honours) also. I work in research and development. Most of the muppets on the internet, its not even worth reading their posts. I'm yet to lose an engine from anything but old age and I have a car that can be daily driven and is in the 11 second bracket now. I've probably put 60k miles on my car since I've owned it.

At that boost level, yeah, .78L (thank you by the way) or 11.5afr is an excellent place to be. Where he is at, .82 is fine.... hell I had one guy tell me to run pump gas @ .85L... I wouldn't do it... not even with the Motec and the FFE kit and the timing SPOT on.

[RETed]

We are all going to be comfortable within our own limits.
Each and every one of our limits is relative...

I can comfortably tune 13BT's within 5% of their max potential with just an EGT gauge.
That's a lot of trial & error + experience.
To me, this is not the ragged edge.
In fact, on a Haltech, this is adjusting "gross" amounts with the PAGE UP / PAGE DOWN keys.
This is initially done on street tuning, and I tell the customer we can get that last few HP's on the dyno - it's just safer that way.

This is also about using tools and using them efficiently.
If you don't know how to use the tools properly, it just usually leads to disaster.
What you can do is learn how to do this, if you're willing to make an effort to do so.

Like TTT said, you're just wasting gas (which could become a factor since analysts are predicting $5/gallon for gasoline sometime this year) and killing spark plugs.
So to me, it's not really a matter of "rate of return" - I see it as having the confidence to be able to use all the tools at your disposal to attain the best result for your investment.


-Ted

[Pete_89T2]

That's what I like to hear! When are you bringing that thing back up here?

I'd like to get up there some time before the DGRR trip, but I'm still looking into what I should do about boost control. I'm pretty happy with the set up as-is, but it would be nice to be able to dial in just a little more boost.

[Roen]

Dave recommends the Blitz SBC, if you have some dime to throw around.

[vrracing]

We leaned it out and got it in line with yall's AFR recommendations. However, it didn't increase the peak boost.

I was looking at BNR's page (http://bnrsupercars.com/) and noticed that the Stage1 is supposed to come with an adjustable wastegate actuator pre-adjusted to 7-8 psi. And if you'll recall, with the EVC turned off we were only seeing 4.5psi. Ah-ha! Bryan forgot to adjust the actuator. Single-man, busy business and shit happens. No biggy. So Friday morning I sent Bryan an email asking him if he had a procedure for adjusting the WG actuator.

I hadn't gotten a response from him by yesterday (Saturday) afternoon so I Googled it and found that on other cars they adjust it by shortening the rod until they just have to pull the rod to refit it to the lever; just a touch of preload. So I put the car up and crawled under it to adjust the rod and... no threaded actuator rod. So I sent him an update email.

Bryan responded shortly after midnight apologizing for installing the wrong wastegate actuator and said to "Add a spring to it and it will gain a couple psi." I responded one minute later asking what size and rate he recommended but alas he did not respond.

I found on a Subi forum (http://forums.nasioc.com/forums/showthread.php?t=589293) they recommend 4" 19.1 lb springs from HD. Any recommendations specific to the Hitachi? Can I put my MityVac on the WG nipple to test that it opens at 7-8 psi?

Thx

[vrracing]

I found this picture of a helper (http://www.6gc.net/forums/index.php?showtopic=68755) spring on a Celica and using a 9.55 lb spring from HD we opened up one end of the spring and hooked it on the wastegate lever shaft inside of the actuator rod and then drilled a hole in the actuator's mounting plate. Using a length of wire to connect the spring to the bracket stretching the spring to about an inch.

We pulled the actuator hose off where it connects to the EBC and used the air compressor to put ~10psi to it and we could see the wastegate open. At that part of the pressure gauge we obviously we not going to be very accurate but the wg did open.

So we took it for a ride and once it got up to temp did a third gear pull and got up to 10.8psi and it only dropped to 8.8 when he let off. This was with the EVC set to 50%. It was 70 degrees outside.

So that's promising. We will use the HVLP paint sprayer's end of hose regulator and gauge use it to get a more accurate w/g opening pressure of 8psi. Then we'll do more scientific runs with logging.

[FerociousP]

There's going to be a slight difference in when it opens under vac line pressure and when it opens under boost pressure (and exhaust gas also pushing it open). But those real world driving levels look promising.

[vrracing]

Yeah, that's a good point since our static tests dont take into account the dynamics of the exhaust gases on the wastegate flapper.

Given that, we could disconnect the helper spring and then slowly turn up the PSIs from zero. When the WG opens, that would corresponding to the 4.5psi WG-spring opening boost we've been seeing. Doubling that and subtracting a smidge (that's a technical term) should get in 8psi range.

[vrracing]

We tightened up the helper spring a bit. I had connected the air compressor with a hose-end regulator and a T feeding the WG actuator and the Zeitronix boost sensor. I tightened the helper spring until the boost gauge was showing ~14psi when the waste level maxxed.

Then we did a quick run with the HKS set to zero and in fourth it peaked a little over 6psi. So I dont think there is a reliable way to statically set the helper spring tension.

Then we set the HKS to 50% and in fourth reached a smidge over 12psi and it held to 11.4. This was going up a pretty steep hill.

http://i366.photobucket.com/albums/oo104/vrracing/March5-1.png

http://i366.photobucket.com/albums/oo104/vrracing/March5-2.png

Looks like we need to lean it out a touch.

The plots show a definite zigzag pattern. Is that the HKS boost solenoid cycling on and off or just noise?

Should we tighten up the helper spring some more so that the HKS doesnt have to work so hard? Or does that matter? I recall seeing on another site while researching helper springs that people were concerned about the duty cycle of their EBCs.

btw, we have an NA 5-speed gauge cluster which has an 8k redline. Was the S5Tii redline 7k like the S4s?

Thx

[Sharingan 19]

still running?

[vrracing]

Yup. Car runs fine as 12psi of boost. The helper spring was the key piece. Havent messed with it since.

Last week the top plastic radiator endcap cracked and was leaking so he installed a Godspeed aluminum rad with a GM shrouded electric fan. Really opened up the engine bay and the polished rad looks really good. It was in the 90s and muggy as Houston here and it cooled very nicely using a Flex-A-Lite thermoswitch to control the fan.

At the same time the kid put a Corksport turbo intake duct as a purely prophylactic measure. Nice piece.

[88turboii]

i have an extra spring on my S5 hybrid too. another problem ive discovered, if you are running the factory turbine wheel, it can cause so much back pressure that it will open the wastegate by itself. the extra spring helps keep it closed until the actuator wants it open. that could have been happening, especially at high rpm. and ive never heard of running too rich that it limits boost, unless its actually misfiring

[vrracing]

Yeah, Bryan @ BNR said the adjustable w/g rod didnt really do much.

[Sharingan 19]

Yeah, Bryan @ BNR said the adjustable w/g rod didnt really do much.

In your particular case, or as a general rule? Seems kinda of silly to offer an "upgrade" that doesn't work... :dunno:

[10thanniv]

I had same issue, lacking boost (6psi) with BNR stage3. I have the adjustable wastegate, which I had to pay for and was set to 12 psi from BNR. I looked for boost leaks for a couple of weeks and couldn't find any. I adjusted the wastegate rod and the boost went up to 7 psi. I finally installed my MBC and got it up to 11psi. Running good now, but wasted money on the adjustable wastegate.

[vrracing]

In your particular case, or as a general rule? Seems kinda of silly to offer an "upgrade" that doesn't work... :dunno:

Bryan forgot to do the adjustable rod on mine (it is supposed to be part of a Stage1 so I didnt pay extra for it) and I asked him how he made the mod. He told me "I cut the rod, weld a coupling nut on it. Then thread the rod end and adjust it that way. Only around a 2-3 additional psi is all you can get out of it"

So he may be doing it as a bonus so someone can get a couple extra psi over stock. I think it might be better to fit an adjustable helper spring mechanism that would better match to typical goals instead.

I finally installed my MBC and got it up to 11psi. Running good now, but wasted money on the adjustable wastegate.

Our HKS EBC and the unaided WG actuator couldn't keep the WG closed so we had to add the helper spring.

[Sharingan 19]

Interesting...

I too have an HKS ECV (EVC 1 actually) and it seemed to have no problem keeping the wg closed to the tune of 15+ psi, however I very rarely (if ever) took the car to redline, so perhaps thats why I never noticed a problem?

[vrracing]

Before the helper spring we would peak at 9.9 @ 4600 and then drop to 7 by 6000 as can be seen in my first post with the graph.

I assume BNR doesnt replace the WG so boost is controlled by a 20 year old spring that has gone thru many heat cycles. It seems reasonable to assume that different springs will degrade at different rates.

I doubt that the version of EVC matters. This one is a Black Edition but I've never been able to figure out which normal edition that maps to. It only displays in kpa but since we use the Zeitronix for monitoring boost it doesnt matter.