Probably the easiest way to test it if he has a spare. The VR sensor should be magnetic, maybe it has a weak pull and is, for lack of a better term, floating and not providing a clean signal to the converter.
I assume you're able to log the signal while the engine is running, does one signal appear longer than the others? can MS display in that kind of resolution?
Edit:
The LX9 3500 uses a hall effect sensor in the stock 3.1/3.4/3100/3400 position, it requires +12V, but would also allow you to eliminate your converter box.
here's the pinout for the 3500 sensor.
Edit again: I haven't confirmed the 3500 sensor works in the early block, but it's probably worth a try. ------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
A (normal) lathe won't turn fast enough to spin a crankshaft to its redline.
I think I would be able to do something with a computer soundcard and a step-up audio transformer to simulate a VR sensor signal. Not as good as a true end-to-end test, but it would be inexpensive!
I was too anxious to troubleshoot things, so I jumped ahead and started working on solutions:
I switched to the optoisolated input on the MS, and I removed the low-pass "Dave" capacitor to remove any possible time-smearing that could merge two notches into one. After doing this, I still lost sync at 3k RPM.
Then, I removed the crank sensor bolt, and I pulled away the sensor from the engine block by a smidgen. This also increased the sensor to notched wheel gap by the same smidgen. Bam, I was able to rev to 4k RPM without a hiccup. Since the engine was cold, I didn't want to rev it any higher, and I didn't have the time before supper to let the car warm up.
With magnetic sensors like this, you want a small gap to maximize the signal level. However, when the gap is too small, in addition to seeing the teeth, you also see the imperfections much more. So the best signal-to-noise ratio will exist at some certain distance; not the closest gap possible.
I suspect that these imperfections are confusing the MAX9924, and that the ideal gap with the MAX9924 is greater than with the DIS brick.
Closed black-boxes such as the MAX9924 are the manager's dream... you can just buy a pre-built solution, and nobody needs to spend time developing an in-house solution. It's all good, until you have problems... you end up wasting time trying to reverse-engineer the black box and guessing at what it's going to do. An in-house solution on the other hand, intimately understood by people in-house, is far easier to understand and debug. In this case, I fell victim to the manager/outsourcing syndrome.
In this case, I will probably test different shims to space the sensor away from the machined mounting pad on the engine block... I'm hopeful that I can find a working solution this way.
My understanding is that the MS tooth interrupt is edge-triggered, and only by rising or falling edges (the user chooses which edge is the most accurate reference edge). So ONLY the reference edges are logged.
Here is an example showing a missing double-notch:
The dizzy (cam) sensor is represented by the green trace; we only see every other edge in the log. In reality, it is a square wave with approximately a 50-50 duty cycle.
The early and late sensors interface with the engine block in the same manner.
However, the reluctor wheels are of a very different design: Early: smaller major diameter, flux through the concentrator depends on presence/absence of a notch. Late: larger major diameter. magnetic flux is directed forwards or rearwards, and the sensor detects this.
So, using an early crankshaft, I have to use an early sensor. I did not study the possibility of using a non-GM sensor with the GM block/crank.
I liked the idea of a 3-wire interface to the ECU, with a robust digital link. Since my sensor didn't do this, I did the converter box instead.
[This message has been edited by pmbrunelle (edited 04-29-2020).]
Glad to see you appear to have it working again, or at least a path forward.
thats an interesting note on the sensor comparisons.
there is a possible 3rd option, the 3900 uses a 58x wheel, and is machined into the crank much like the 2.8/3.1/3.4 reluctor. it may be a drop in for the early sensor, and have the correct standoff and orientation. I would look into it just because it would allow me to remove an additional interface that can fail, but I understand if you want to run what you have as well.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
I shimmed the crank sensor with a 0.035" washer; there is still the occasional sync loss at high RPM/acceleration, but it's much better. I'll try another shim later on.
I also decided to check the timing with a strobe lamp; it was 17° retarded compared to the MS3's commanded timing. I applied a 17° global offset in the MS3 to make the commanded and measured timing values match each other. This made the car run a bunch better, including reducing its overheating tendency.
With a 4 psi wastegate actuator spring setting, the wastegate doesn't seem to have the capacity to divert enough exhaust gas around the turbine. The boost increases linearly to 8-9 psi near redline. To solve this issue, I'll probably just install the 10 psi spring kit in the actuator. With a higher boost pressure setting, less wastegate flow will be required.
It is typical for issues to arise on new engine setups... after 100 km so far, some of the exhaust manifold bolts loosened. Some fell out while driving. I was using regular ARP bolts with the included flat washers. I don't know if the Volkswagen gaskets compressed; perhaps I should have retightened the bolts daily during the initial settling period. I'm not yet sure how I want to address this issue.
Perhaps serrated-head bolts would help? Claude thinks that a stud+nut arrangement might be better.
Get some ARP Stainless bolts and regularly retorque them. You might also want to try longer bolts and spacers in order to improve the stiffness ratio of the joint.
Also might try spot-facing the surface of the flange that the bolt head seats against.
Glad to hear the car is running much better now Patrick! As far as the bolts loosening I believe is becasue the metal's different expansion rates, the head and the manifold. And now is more pronounced becasue of the flex pipes in between. I've never had that problem and I always use stronger bolts and the stock gaskets but I do use red Loctite. I put some loctite on the threads and let it dry, then I screw them in and over torque them a bit and that's it. I hope you find a solution for it!
I shimmed the crank sensor with a 0.035" washer; there is still the occasional sync loss at high RPM/acceleration, but it's much better. I'll try another shim later on.
Perhaps serrated-head bolts would help? Claude thinks that a stud+nut arrangement might be better.
I don't think it's a good idea to further distance the crank sensor from another 35 ". Because the crank sensor is a magnet and it has a distance limit to be respected for a good reading, 35 "(Your original distance) + 35" + 35 "= it's too much for the magnet.
Most turbo engines or supercharger manifolds are assembled with studs and nuts, it's the same idea when you assemble engine heads with ARP nut studs
And now is more pronounced becasue of the flex pipes in between.
The flex couplings are supposed to make it less pronounced.
quote
Originally posted by claude dalpe:
Most turbo engines or supercharger manifolds are assembled with studs and nuts, it's the same idea when you assemble engine heads with ARP nut studs
OEMs use studs for ease of assembly during production.
Studs do not have any magic in them.
Using spacers to make the exhaust bolts longer improves the stiffness ratio of the bolted joint... that may help significantly.
I've been using stainless bolts and torquing them to 15-18 ftlbs with anti-seize. I have pretty good luck, but a couple of problem children that don't like to play nice.
[This message has been edited by Will (edited 05-03-2020).]
Originally posted by pmbrunelle: after 100 km so far, some of the exhaust manifold bolts loosened. Some fell out while driving. I was using regular ARP bolts with the included flat washers. I don't know if the Volkswagen gaskets compressed; perhaps I should have retightened the bolts daily during the initial settling period. I'm not yet sure how I want to address this issue.
There are exhaust bolts available either drilled for safety wire or tear drop locks. Both will prevent the bolts from walking out. However, if the root of the issue is the gasket relaxing at temp (copper is known for this), then you will need to retorque a couple of times... which likely will fix the issue w/o needing to use wire or other positive locks.
I shimmed the crank sensor with a 0.035" washer; there is still the occasional sync loss at high RPM/acceleration, but it's much better. I'll try another shim later on.
I also decided to check the timing with a strobe lamp; it was 17° retarded compared to the MS3's commanded timing. I applied a 17° global offset in the MS3 to make the commanded and measured timing values match each other. This made the car run a bunch better, including reducing its overheating tendency.
With a 4 psi wastegate actuator spring setting, the wastegate doesn't seem to have the capacity to divert enough exhaust gas around the turbine. The boost increases linearly to 8-9 psi near redline. To solve this issue, I'll probably just install the 10 psi spring kit in the actuator. With a higher boost pressure setting, less wastegate flow will be required.
It is typical for issues to arise on new engine setups... after 100 km so far, some of the exhaust manifold bolts loosened. Some fell out while driving. I was using regular ARP bolts with the included flat washers. I don't know if the Volkswagen gaskets compressed; perhaps I should have retightened the bolts daily during the initial settling period. I'm not yet sure how I want to address this issue.
Perhaps serrated-head bolts would help? Claude thinks that a stud+nut arrangement might be better.
What I see on this image of the manifold (lower in the link) is that it is on the side where there are no flex pipes between the turbo and this end of the manifold and after this part of the manifold there is a flex, + it is the bolt from the top which is missing so it is the weight of the turbo which moves this part of the manifold which does not have the rest of the 2 other cylinders on the manifold to prevent it from pivoting.
I continued the investigation, and here is the smoking gun!
Right side of photo: New gasket (IAP 111251261B). Sandwich made of two metal layers with pink fibers in between. A fire ring prevents the exhaust gas from directly touching the fibers. Left side of photo: #5 gasket, completely flattened. The fibers are gone. I believe that the fibers burned away in the car.
The pink fibers appear to be cardboard. With a new gasket, I was able to set it on fire. The white/grey ash crumbled when I touched it.
Will: Why stainless fasteners? Will they creep less with the exhaust heat?
Claude: Yes, the #5 gasket is the most solicited, since it must deal with the mass of the turbo. However, the exhaust bolts on all cylinders were loose or missing. I inspected the #1 gasket, and most of the fibers were gone on that one too.
Conclusion: I need to select better gaskets before I start worrying about anti-loosening techniques on the bolts.
[This message has been edited by pmbrunelle (edited 05-03-2020).]
Claude has a point. I built a bracket bolted on the upper 2transmission bolts to hold the weight of the downpipe (when I had one). And that was the trick. Never had a loose bolt or a warped exhaust manifold. That turbo seems heavy and its putting a hurtle when hot on the pipes. Specially with those accordeon flex pipes, if you didn't have them the upper bolt hole would not gave to the weight of the turbo because there were no play to give. Or get a set of those gaskets and burn them and then put them in.!
[This message has been edited by La fiera (edited 05-03-2020).]
There are exhaust bolts available either drilled for safety wire or tear drop locks. Both will prevent the bolts from walking out. However, if the root of the issue is the gasket relaxing at temp (copper is known for this), then you will need to retorque a couple of times... which likely will fix the issue w/o needing to use wire or other positive locks.
If you have to safety wire something on a car, there's something else wrong with the joint design. I understand it as a belt and suspenders approach used in conjunction with good joint design on airplanes when human life can be lost due to an engine failure... but pretty much any application on a car can be set up not to require it.
Aluminum flywheels getting hot and creeping out from under the flywheel bolt heads is a prime example of this... the bolt don't need safety wire; the joint design is bad.
[This message has been edited by Will (edited 05-03-2020).]
Aluminum flywheels getting hot and creeping out from under the flywheel bolt heads is a prime example of this... the bolt don't need safety wire; the joint design is bad.
I'm going to dissagree with you Will, its not a bad design, its the wrong approach. I've seen a lot of aluminum flywheels get loose and the main reason is becasue people install them like is a steel flywheel, bolt to flywheel. If you dont install a wide WASHER to spread the load of the torque of the bolt on the alumimun flywheel IT WILL GET LOOSE because of the different expansion rates between the bolt and the flywheel and the hard steel bolts eat on the soft aluminum. Instaliing a wide washer on the bolt applying the torque results in a wider foot print to keep it in place and prevents the bolt from walling the soft aluminum its simple physics and common sense. They don't teach common sense at school or college.
The support leaves the turbo free to move sideways, so acceleration/braking/turning loads (due to the turbo's mass) are taken up by the cylinder #5 flange.
If the turbo were fully fixed, then the exhaust pipe and #5 flange would not see any acceleration/braking/turning loads.
However, if the turbo were fully fixed, the exhaust pipe would try to expand with the heat, creating stress in the pipe and #5 flange.
When I selected the present exhaust concept, I concluded (with some very basic calculations) that the thermal stress (in the pipe + flange) from a fully fixed setup was worse than the stress from acceleration/braking/turning loads with a rod-end support.
It is possible that this exhaust scheme is not workable. If that is the case, I suppose I will have to revisit the exhaust setup
Being a certified Fiero-nut, I looked in my parts collection and I found TWO pairs of the Fel-Pro MS 93045 exhaust gaskets for the 2.8 Fiero. They look like they have a bunch of graphite in them.
So I'm going to try with the Fel-Pro gaskets and probably retorque after some driving.
If only gasket #5 fails afterwards (which we could assume is due to acceleration/braking/turning loads), then I'll look into a copper gasket for flange #5 to stiffen that joint. I may choose to use copper gaskets for all flanges for standardization.
[This message has been edited by pmbrunelle (edited 05-03-2020).]
I'm going to dissagree with you Will, its not a bad design, its the wrong approach. I've seen a lot of aluminum flywheels get loose and the main reason is becasue people install them like is a steel flywheel, bolt to flywheel. If you dont install a wide WASHER to spread the load of the torque of the bolt on the alumimun flywheel IT WILL GET LOOSE because of the different expansion rates between the bolt and the flywheel and the hard steel bolts eat on the soft aluminum. Instaliing a wide washer on the bolt applying the torque results in a wider foot print to keep it in place and prevents the bolt from walling the soft aluminum its simple physics and common sense. They don't teach common sense at school or college.
That's part of the joint design... the contact stress is too high for the materials being joined.
When I was in school, the stress in a material underneath the bolt head was part of the curriculum.
There was no deep study of the subject, but there was a brief overview.
That's unfortunate, as impacts from the thermal environment are unavoidable, yet rarely treated in engineering education. In this case, the operating temperature can get high enough that the aluminum will creep unless the contact stress is reduced via washers as Rei says or a steel doubler to cover the entire flywheel bolt pattern. Not a problem at room temperature, just at elevated temperature.
That's unfortunate, as impacts from the thermal environment are unavoidable, yet rarely treated in engineering education. In this case, the operating temperature can get high enough that the aluminum will creep unless the contact stress is reduced via washers as Rei says or a steel doubler to cover the entire flywheel bolt pattern. Not a problem at room temperature, just at elevated temperature.
Will I do not say that your answers are not good or good, but I find that you have an answer to give to all those who answer the problem, I do not agree with all your statements but me I leave room for others to give their opinion without contradicting them. I know Patrick very well and he is a very good engineer and he is wrong some time maybe you too? What do you think.
Rei a constaté que les écoles n'apprenaient pas aux élèves le sens commun d'employer des rondelles en-dessous des têtes de vis.
Par la suite, moi j'ai dit que le comportement d'une matière sous la tête de vis faisait partie du cours à l'école, mais que ce sujet a été abordé seulement en surface. Donc les étudiants sortent avec de notions approximatives, mais sans trop connaissances approfondies.
Will ensuite a commenté que c'est dommage que les écoles (de façon général) n'enseignent pas en profondeur les effets de la chaleur sur les systèmes, genre l'effet de la chaleur sur un joint boulonné. Sûrement qu'il a vu des gens sortir de l'école et avoir du mal à faire leur travail parce qu'ils manquaient des bases scolaires. Rien de mal dans ce qu'il a dit (dans le texte tu as cité)!
I think it comes down to every industry thinks their domain is the most important, and feel that subjects of their domain are what should be taught to students.
The schools on the other hand are trying to produce students capable of working in a variety of jobs after school. Therefore, the schools cannot spend too much time teaching any one subject.
As a student, I did not want an overly-specific education, because I felt that it would lock me in to certain industries. I wanted the most flexibility with regards to possible employment.
[This message has been edited by pmbrunelle (edited 05-04-2020).]
Rei a constaté que les écoles n'apprenaient pas aux élèves le sens commun d'employer des rondelles en-dessous des têtes de vis.
Par la suite, moi j'ai dit que le comportement d'une matière sous la tête de vis faisait partie du cours à l'école, mais que ce sujet a été abordé seulement en surface. Donc les étudiants sortent avec de notions approximatives, mais sans trop connaissances approfondies.
Will ensuite a commenté que c'est dommage que les écoles (de façon général) n'enseignent pas en profondeur les effets de la chaleur sur les systèmes, genre l'effet de la chaleur sur un joint boulonné. Sûrement qu'il a vu des gens sortir de l'école et avoir du mal à faire leur travail parce qu'ils manquaient des bases scolaires. Rien de mal dans ce qu'il a dit (dans le texte tu as cité)!
I think it comes down to every industry thinks their domain is the most important, and feel that subjects of their domain are what should be taught to students.
The schools on the other hand are trying to produce students capable of working in a variety of jobs after school. Therefore, the schools cannot spend too much time teaching any one subject.
As a student, I did not want an overly-specific education, because I felt that it would lock me in to certain industries. I wanted the most flexibility with regards to possible employment.
I'm not saying that he said something bad. I just put this answer (quote) because he was the one who spoke last. I just say that he has something to add to everything that others say, he contradicts others. I don't always agree with what he says but I don't contradict him he should do the same. It is up to the topic starter to judge the answer if it's good or not for him! Maybe I misspoke, it's not mean what I say, it's only an opinion.
I speak of Will very highly and I had a hunch Patrick was a smart guy also. And Claude, I don't know you very well but I can sense you are a very knowledgeable guy too. I quit engineering school when I prove my teacher wrong and he tried to argue he was right when the results in front of the class were wrong. I've been wrong many times and when I'm wrong I admit it, I don't have all the answers. I guess is my caribbean nature that makes outspoken but I mean no harm. The way I see it is we just sharing ideas in this case to help Patrick. Calculations may give you a solution in paper and an idea, but the real world is a different story. One thing I learned about engineering school is that calculations are for reference only, when you apply them to the real world more calculations are needed and the circle keeps going around.
Patrick, Ta 'to montro! Tu cree que ere un bacano pero lo que ere 'e un palomo. Tanto calculo pa' na. De na' te valio la ecuela de ingenieria. Pero na', seguimo ahi pa' lante!
Again, we are just sharing ideas, isn't that what forums are created?
By the way, my boyhood hero and all time favorite F1 driver is Gilles Villanueve, a french canadian like Patrick and Claude.
Dammit! I had to get google translate out for that! Lol!
My understanding is that copper gaskets also creep quite a bit as well, straight stainless is probably the best bet.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Patrick Ta 'to montro! Tu cree que ere un bacano pero lo que ere 'e un palomo, . Tanto calculo pa' na. De na' te valio la ecuela de ingenieria. Pero na', seguimo ahi pa' lante!
Patrick, je vais te montrer! Vous pensez que c'était des vacances, mais c'est un pigeonnier. tant de calcul bon ou mauvais. L'école d'ingénieur en valait la peine. Mais nous y sommes toujours!
Patrick, I'll show you! You think it was a vacation, but it's a dovecote. so much good or bad calculation. The engineering school was worth it. But, we are still there!
Patrick Ta 'to montro! Tu cree que ere un bacano pero lo que ere 'e un palomo, . Tanto calculo pa' na. De na' te valio la ecuela de ingenieria. Pero na', seguimo ahi pa' lante!
Patrick, je vais te montrer! Vous pensez que c'était des vacances, mais c'est un pigeonnier. tant de calcul bon ou mauvais. L'école d'ingénieur en valait la peine. Mais nous y sommes toujours!
Patrick, I'll show you! You think it was a vacation, but it's a dovecote. so much good or bad calculation. The engineering school was worth it. But, we are still there!
Lol!! You are way off Claude but that's fine. That was Dominican Spanish slang. If a Spaniard goes to The Dominican Republic and try to understand the slang, he'll have a hard time. Its like if you go to Haiti, the other part of the island. Haitians speak Creole, it's derived from french but you'll probably could understand some but not all. But regardless, I was was just complementing Patrick and now you also. I really like your diplomatic approach. I've been wanting to go to the GIlles Villanueve museum, if I make the trip I hope I can meet you and Patrick in person!
Lol!! You are way off Claude but that's fine. That was Dominican Spanish slang. If a Spaniard goes to The Dominican Republic and try to understand the slang, he'll have a hard time. Its like if you go to Haiti, the other part of the island. Haitians speak Creole, it's derived from french but you'll probably could understand some but not all. But regardless, I was was just complementing Patrick and now you also. I really like your diplomatic approach. I've been wanting to go to the GIlles Villanueve museum, if I make the trip I hope I can meet you and Patrick in person!
Definitely Mooresville is not that far away from here. You know Gilles' museum is really not far from my home 30 miles, me and Patrick are from Montreal (he works at grand-mère) I speak on my behalf but I am certain that Patrick will also welcome you and we go to the museum together
Definitely Mooresville is not that far away from here. You know Gilles' museum is really not far from my home 30 miles, me and Patrick are from Montreal (he works at grand-mère) I speak on my behalf but I am certain that Patrick will also welcome you and we go to the museum together
That will be awesome Claude!!. Now,back to Patrick's build. Hello, Patrick! Update please!!
Originally posted by La fiera: Lol!! You are way off Claude but that's fine. That was Dominican Spanish slang. If a Spaniard goes to The Dominican Republic and try to understand the slang, he'll have a hard time.
It was a challenge (I did not understand in the end), but I like challenges!
In preparation for the bolts to arrive, I have removed the manifolds and cleaned them with non-chlorinated brake cleaner, as well as the sealing surfaces on the heads.
Before cleaning, I took this photo of the rear manifold:
From the carbon, we see that #1 and #5 were leaking.
quote
Originally posted by ericjon262: My understanding is that copper gaskets also creep quite a bit as well, straight stainless is probably the best bet.
I have stainless on the turbine inlet flange. That joint (and the piloted V-bands) have held up so far (100 km).
This is what I did on the turbine inlet: Serrated-flange nut (10.9, zinc-plated) Faced nut seating surface on cast iron turbine housing (was as-cast with draft angle on the ATP housing as-delivered) Machined sealing surface on cast iron turbine housing (while porting the housing, I damaged the sealing surface, so the local machine shop fixed this for me) Thin layer of wheel bearing grease (apparently an old trick; burns away and leaves carbon which can seal small gaps) Thin stainless steel gasket. Has an embossed ring around the hole in the middle. Thin layer of wheel bearing grease Machined (as-bought) 304 stainless exhaust flange with tapped holes Double-ended zinc-plated studs, anti-seize on both ends.
For the manifolds, I thought about using no gasket, just metal-on-metal (with some wheel bearing grease), but I'm not sure if the sealing surfaces (head + manifolds) are good enough (surface finish + flatness) to do that.
For Volkswagens, I found copper gaskets (3-week delivery time if I order some), but I haven't found straight stainless yet.
[This message has been edited by pmbrunelle (edited 05-06-2020).]
Thin layer of wheel bearing grease (apparently an old trick; burns away and leaves carbon which can seal small gaps) I know this old trick but for your manifold I don't think it works because : it work only on a very flat surface with somes small pit hole on the surface .
For your turbo flange you have install studs and nuts with good result even if it moves !
Using spacers to make the exhaust bolts longer improves the stiffness ratio of the bolted joint... that may help significantly. I agree with Will for the spacers and longer bolts. My reason is that the spacers act like a spring when the metal becomes hot and expanded and when it cools. But you have to re torque them often. Doesn't Look Good I prefer the studs and nuts for the look.
Ask ericjon262 maybe he know a parts number for the stainless gasket? for me it's the best
First, I cut them into individual pieces, because I didn't like the look with the connecting strips.
I know that people here often dread the exhaust manifold gasket job and the drilling-out of broken rusty bolts that comes with it.
Well, when the bolts pretty much unscrew themselves (and even fall out on the road), the job is a piece of cake
I installed the Proform header bolts in 9 places. For the 3 other places, I used the stock studs that are used to support the front manifold's heat shield.
I will go back and retorque everything after some driving.
[This message has been edited by pmbrunelle (edited 05-08-2020).]
I went out driving tonight and the manifolds are sealing to the heads (for now).
And now, the next problem: boost creep!
Prior to leaving the garage, I forgot to install the wastegate actuator's rod end onto the wastegate lever...
Here is a 5-second WOT pull I did on the highway from 2751 RPM in 4th gear:
The manifold pressure climbed steadily to 180 kPa absolute at which point the ECU's boost limiter intervened with a spark cut. That was with the wastegate flapper fully open the whole time. Ambient temperature was about 2 °C.
So apparently my wastegate doesn't flow enough. I think I'm going to attempt to port the wastegate.
If that doesn't work, then I may switch to a bigger external wastegate. Thoughts?
If I go to WOT in 1st gear from idle, the turbo lag is such that the 180 kPa boost cut isn't reached until an engine speed of about 5500 RPM.
[This message has been edited by pmbrunelle (edited 05-09-2020).]
I don't remember what type of muffler you have on the car, but a free(er?) flowing muffler may help with wastgate performance without the fabrication required to install an external WG. from what I remember in your video the car was fairly quiet, and sounded like you could open it up quite a bit, without getting excessive.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
The manifold pressure climbed steadily to 180 kPa absolute at which point the ECU's boost limiter intervened with a spark cut. That was with the wastegate flapper fully open the whole time. Ambient temperature was about 2 °C.
So apparently my wastegate doesn't flow enough. I think I'm going to attempt to port the wastegate.
If that doesn't work, then I may switch to a bigger external wastegate. Thoughts?
If I go to WOT in 1st gear from idle, the turbo lag is such that the 180 kPa boost cut isn't reached until an engine speed of about 5500 RPM.
I don't remember what type of muffler you have on the car, but a free(er?) flowing muffler may help with wastgate performance without the fabrication required to install an external WG. from what I remember in your video the car was fairly quiet, and sounded like you could open it up quite a bit, without getting excessive.
It's pretty much like a glasspack, but with a case that's larger off to one side.
Actually, it seems like a more restrictive muffler would help with the boost creep problem, despite diminishing the wastegate performance.
The turbine is driven by a pressure difference, so increasing the pressure at its discharge (i.e. with a thin restrictor plate inserted into the discharge V-band) should reduce the problem.
If we perform a thought experiment, lets imagine a restrictor plate at the discharge V-band with a 1/2" orifice. I don't think there would be much boost in that configuration.
quote
Originally posted by Will: Sounds to me like your turbo is too small
Now I have a 0.63 A/R turbine housing from ATP. They do offer a 0.82 A/R version of the same thing (also machined for the Stage III turbine wheel), which I am considering.
I don't know how much difference it would make though. I don't even know what A/R means.
Area/Radius should result in units of length, yet this parameter is presented as a unitless quantity What am I missing that the entire remainder of the Internet seems to understand?
I am going to ask ATP if the inlet flange to turbine axis relationship is constant between their 0.63 A/R and 0.82 A/R housings. If so, then the 0.82 A/R housing would bolt into the White Bug. I'd still probably port the 0.82 A/R housing's wastegate passage.
Now I have a 0.63 A/R turbine housing from ATP. They do offer a 0.82 A/R version of the same thing (also machined for the Stage III turbine wheel), which I am considering.
I don't know how much difference it would make though. I don't even know what A/R means.
Area/Radius should result in units of length, yet this parameter is presented as a unitless quantity What am I missing that the entire remainder of the Internet seems to understand?
I am going to ask ATP if the inlet flange to turbine axis relationship is constant between their 0.63 A/R and 0.82 A/R housings. If so, then the 0.82 A/R housing would bolt into the White Bug. I'd still probably port the 0.82 A/R housing's wastegate passage.
Mostly joking about that... I'm sure you did your homework on turbo selection. If you think finding the definition of AR is bad, try finding the definition of "trim". The 10 psi wastegate spring sounds like the right answer for your "problem".
And yes, AR SHOULD have units of length, but mostly isn't presented that way... welcome to the world of hot rodding.
I just read this thread for the first time today and one word comes to mind..............Impressive.
Hehe lets wait until it runs correctly before giving the accolades... it could still blow up!
quote
Originally posted by Will: The 10 psi wastegate spring sounds like the right answer for your "problem".
Yes, a "problem" is often not a problem as such; it is rather a person's interpretation of a situation.
The present setup: -ECU's MAP limiter is set to 200 kPa -The wastegate actuator is completely disconnected. The wastegate flapper is now free to swing wide open. It is in the "maximum bypass" configuration when the exhaust blows it open.
The problem didn't seem so bad initially (my statement about the 10 psi spring possibly patching things), but that was just for 1st gear.
Doing more structured tests in 2nd, 3rd, and 4th gears I hit the ECU's 200 kPa MAP limiter at progressively lower RPMs... even with the wastegate in maximum bypass configuration. The turbo lag is less prominent in the higher gears where engine acceleration is lower.
It is possible that for a higher boost level, the wastegate capacity would become sufficient, but I am not ready to try more than 200 kPa for the moment. My fuel injectors (30 lb/hr) are pretty much maxed out with 200 kPa of manifold pressure, and I haven't yet activated the water injection yet (I'm trying to debug only one system at a time).
So my current objective is to increase the wastegate flow capacity such that the manifold pressure can be kept below 200 kPa in all conditions.
This is my plan to be completed in order of increasing expense/difficulty:
Step 1 (completed): Remove the wastegate swingvalve assembly from the car, and increase its angular travel to increase the curtain area.
Original setup:
Metal ground away on arm, and material removed from the casting:
With modifications, the swingvalve can travel further:
This wasn't enough; it's not the slam dunk I was hoping for. If this didn't change much, then perhaps the bottleneck is in the wastegate passage of the turbine housing.
Step 2: Remove the turbo from the car, port the wastegate passage in the turbine housing.
Step 3: Install the 0.82 A/R turbine housing, unported.
Step 4: Port the 0.82 A/R housing.
Step 5: Build a block-off adapter to replace the swingvalve assembly. Add an external wastegate to the 2-into-1 merge. Or maybe build an internal wastegate with a bigger puck (and corresponding larger passage).
[This message has been edited by pmbrunelle (edited 05-11-2020).]
What am I missing that the entire remainder of the Internet seems to understand?
