Boost falling off

[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.

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

1. 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.
2. 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.
3. Get an EGT for $80. This would have little value without professional tuning and hours of dyno time.
4. 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]

Originally Posted by 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.

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

1. 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.
2. 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.
3. Get an EGT for $80. This would have little value without professional tuning and hours of dyno time.
4. 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]

Originally Posted by 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.

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

Originally Posted by vrracing

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.

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

1. 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.

1. Leaning it out will net more power though.
   
   
   

   Originally Posted by vrracing

   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.
   
   
2. 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.
   
   

   Originally Posted by vrracing

   Spend $400+ on professional tuning and dyno time.

That is excessive by our billing standards

Originally Posted by vrracing

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.

Originally Posted by 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.

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

Originally Posted by sa22c

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]

Originally Posted by TitaniumTT

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 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 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 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.





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?