98Z28CobraKiller

iTrader: (17)

Quoted for truth. We currently are running the boost beta on 4 vehicles that I tune. Our flagship is the 7 sec Formula. Because we live in Florida, we haven't been able to get any testing done over the summer as it rains every single day down here.

Anyway, I'm no noid specialist but we had some that we got elsewhere as Holley didn't have any at the time. We had nothing but issues. Got a couple of the Holley ones and they worked perfect. The noids that AMS sells seem to work well also.

Anyway, I just got an email this afternoon with the newest upgrades that we had requested from the last BETA feedback. I haven't even looked at it yet but we are hoping to test Wednesday night with the Formula. It also has the latest modded ECU that is supposed to work with the stock coils. Seems to work good on the street but the street can't hold much boost.

Anyway, to answer the OP, it's close.

One other thing. The manual for this thing is out of control. IMO, anyone with a turbo setup should read it as it gets into lots of theory and is well written. It's not 100% complete yet but it's good technical reading if you aren't the type to go cross eyed while reading technical manuals. Not sure if I'm allowed to share that.

silver_82

^^^ X2 the user manual is i believe 58 pages long. And imo you better read and re-read it to fully understand what your doing. And stevieturbo i had surging boost most likely because i was too aggressive on the pwm DC and its why i urge anyone that does it this way to setup failsafes because your not going to have any idea what dc to start with. Dome volume, hose length and how aggressive you want the boost curve will all change the DC.

An open loop boost statagy is more dangerous imo than closed loop pid control because there is nothing saving you from overshoot if you get it wrong. Bench testing and trial and error on a non running engine are your friends regardless what type of control you want

stevieturbo

You dont know what DC to start with ? You have to be joking. You start with ZERO !!! You see what w/g pressure only is, and then you gradually increase the DC until you reaech the desired boost pressure. There is nothing difficult, dangerous or hard about it. It is a very simple process, and exactly the same for any boost controller or ecu I have ever used.
There is no excuse for having boost surges other than bad setup.

And failsafes go without saying for any boosted engine regardless of how you control boost.

If people do not add them right from the start they deserve all the problems that could happen.

There is nothing dangerous whatsoever about open loop, and any closed loop setup has to start as open loop in the first place anyway because you still need to tell the controller the base duty's required for any given boost pressure.
Whether it's a simple controller or proper one built into the ecu. They all operate the same way.

silver_82

If you want gate pressure yes you leave it at zero but the people in this post are wanting more than gate pressure so you have to put in some DC values and for those without any experience of manual control you have no idea what to put in. A single 38mm gate will require different numbers from someone running twin 44mm gates. I never said i had it set perfectly, and its obvious since i had occilating boost that it wasnt right. I got tired of messing with it and now i dont use that method.

This is a forum and people come on here to look for advise not a smartass saying if they dont do something they deserve to have there engine blow or crash or whatever.

If its so easy then tell me what numbers to put in. 13lb gate springs. I want gate pressure on the brake. Build 3lbs as fast as possible .5 seconds into the run then build 4lbs more over 4 seconds. Twin 44mm gates with one 3 port solenoid. 2step is set at 4900 and the converter flashes to 5500 with 13lbs on t-brake release. What other info do you need?

stevieturbo

You really havent taken on board anything Ive said ?

Your last question is as daft as asking "how many turns do I need to turn my MBC to achieve.....boost?"


And the answer is the exact same as tuning boost electronically. I'll put in in caps as you missed it first time around. START FROM ZERO AND WORK UP
There is no generic answer that x % duty will give x psi boost. the same with any controller.
It is trial and error the same way you set up any boost controller. There is nothing complicated or difficult about it. You dont start from maximum boost and work down, the same way you dont try and tune an engine starting from 8000rpm and working back to idle.
So I'll elaborate. Starting from zero and working up doesnt mean going from 0 straight to 99 then 100.
It doesnt mean 98 either.
It means try 10%, then 20%, then 30% and each time see how much boost the car makes, then you can plot exactly what DC is require at any given rpm to achieve your desired boost.
Oddly, the exact same way you would try an MBC, or EBC.

Yes people do look for advise, so why ignore what has already been said ? Ive been very descriptive about how it works. Have you read any of it ?
If you cannot understand, or are not interested in taking some time to learn, why ask in the first place ?
That's when maybe it's better and safer to pay a tuner to do it. They have taken the time to learn and understand.

silver_82

Yes my last comment was suppost to get you to say "trail and error" and that there is no way you can know what the DC values are suppost to be with out testing. I was trying to get a boost curve as to not overpower the tire at the track and still be as fast as possible. I only speak for myself when I say "I had difficulty" maybe others wont, maybe others are only looking for a fixed increase over gate psi which is easier to achieve. I did not start from 100, or 99 or even 98 as you suspect. I started low (30%, and this netted a 1.5psi increase over gate)and worked my way up just as you described, however when boost goes up the DC will go down to maintain the same gate psi, here is a variable, wastegate motion will cause an increase in dome pressure if the solenoid is closed, another variable, it is very common on shifts for the boost pressure to spike up, another tuning variable if you want to get rid of the spike. and so on.

On my setup I had the b+ to the noid wired to a "High boost switch" this would only apply power to the noid under a certain KPA window, i used trans brake input, low fuel pressure, and lean afrs to interupt the power as well. PWM control was done on the ground side.

I had no problems increasing the boost slowly and at lower levels its when I tried to get appressive with the curve or increase boost by a substantial amount is when I had surging, (from it hitting my max KPA value) once the boost dropped back into the window it began to build again. This is why I had surging boost.

With more time im sure I could of retained better control however ( like I said earlier) I got tired of messing with it and now dont use that method. My point was for others to setup some saftey measures, and I was NOT saying that the manual pwm contol shouldnt be used. My first response to you was that you can use the method. You should read posts thoughly as well. Maybe your not trying but you come off as snooty/ arragant in your posts. A rep from holley even gave some advise on the solinoids and you questioned them. The noids holley uses and recommends with their sofware are not the same as the mac style. They operate at a different hz than the mac style and are more suseptable to voltage irregularities

rotary1307cc

iTrader: (5)

Chris, he is a "guru". It doesn't pay

stevieturbo

Duty's if anything will either stay the same as rpm rises to maintain the same boost, or you will need more duty as the revs climb to maintain boost.
Just depends on the tubochargers ability to create boost, and the wastegates ability to flow, and I guess if you have the system plumbed up correctly.
I have hardly ever tuned a car in the last 20 years that has required less bleed as the rpm's climbed to maintain boost pressure other than when trying to maintain a low boost pressure with a smaller than ideal wastegate, and for at least 10 of those years Ive been using ecu's to control boost. They all want the same or more bleed as the rpm's rise.


I can only see interrupting power to the solenoid as a bad thing and leading to erratic boost control. The only time you could remove power is when the engine doesnt actually have any ability to make boost. But then you wouldnt need to remove power then anyway.
If you remove it when it does have the ability to make boost, it will affect adversely boost control the ecu is trying to achieve.

And I questioned Holley's comment about voltage at the solenoid. They mention behaviour at lower voltages can vary, so I rightly queried why they are seeing lower than the normal 12-14v ?
You should never be seeing voltages less than 12v in the first place so it seems a strange comment to make. If they are recommending an unreliable or inconsistent solenoid...why are they ? I dont believe they would do that.
The MAC solenoid IS the industry standard when it comes to boost controllers, although there are many alternatives.

And as for trial and error. I did clearly state this days ago in this thread.

stevieturbo

I dont claim to be an expert or guru at anything.

But Ive been using ecu's to control boost for over 10 years. It isnt exactly difficult unless you choose to make it difficult.

silver_82

We are saying the same thing when u say more bleed with rpm/boost and i say less DC because i was using a single 3 port noid where the unactivated solinoid is in the "vent" position.

This is also why i pulled power from the noid when my desired boost went too high, cutting the power reverted all control back to the wastegate spring. This sounded like a good idea to me, because if i didnt pull B+ away what would prevent even more overboost. Answer. . . Nothing.

silver_82

In your above post u mention more duty cycle is more bleed. So for that to be true you have your solenoid plumbed to put boost pressure on top of the gate in an "unpowered" state. When you turn on the noid in your case it vents dome pressure.

Why in your previous posts are you saying to start with 0 duty cycle? This would be applying boost to the top of the gate all the time and certainly cause over boost.

U must be using only the lower port in your case.

stevieturbo

I would never implement a boost control system where default boost is higher than base spring pressure. That is the wrong way to do it with any system unless you are fully aware of the difficulties and risks it can cause. Wouldnt matter what method of control you were using, you simply do not do it.

And no, normal boost control can be configured blowing into bottom, or top and bottom, bleeding pressure off top or bottom as required to achieve the desired boost.
Or better still use a 4 port for total control as it allows you to isolate to or bottom ports as required, but with no risks as default is w/g pressure only.

The way YOU have it configured you would always be blowing the w/g shut. The ONLY time I would ever do that is if you were using lots of boost, ie 30psi and upwards where the w/g spring is too soft and you have no other means of increasing boost. Again, that would be a last resort effort only and I have used it once before. I would never recommend anyone doing it though because of the risks, and it was because I had no other options in the timescale I had.

silver_82

Your not following me and i was just trying to fig out how u had it plumbed in your example. Not trying to prove u wrong.

My setup isnt defaulted to shut the gate. I had a single solinoid that was set up as vent to atmosphere in an unpowered state, and this solenoid was feeding the top of the gate. The lower gate port has an uninterupted reference to the compressor discharge

stevieturbo

In default state, whatever way you want to call it. The w/g should always run spring pressure plus boost blowing it open.

The solenoid at 0% should allow free passage of air from compressor to wastegate bottom port.

There are many ways to plumb the system up so this is achieved.

At 100% you can either blow into the top, you can bleed off the bottom, or you can block a boost signal altogether from the bottom port in order to raise boost. There are various ways to configure it depending on the sort of boost you want to run relative to spring pressure and also dependant on the overall engine/turbo package.

Zero4488

iTrader: (10)

Anyone feel like sending me the beta to play with?

71 chevy

iTrader: (18)

^^^^what he said

71 chevy

iTrader: (18)

silver_82,

does the boost setup allow you to set the working limits of the solenoid? ie
ive found that my solenoid at 30hz only works between 15% and 40% dc
at 20hz is works between 10% and 62% dc.

Is there a way to put this in the software so it doesnt even bother trying to work outside those limits?

silver_82

Im using the holley solenoids and I leave the DC table blank, @ 0 the pid controller does it all for you.

and yes you can in your case tell the ecu to only hit the solenoid with a certain DC

71 chevy

iTrader: (18)

thanks man. hey, do you mind posting a pic of how this is set up?

silver_82

did you get the beta version or are you trying to control boost via configuable output?