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No direct experience. However, I understand that the Turbosmart WGA use a larger diameter diaphragm. This means that, for the same waste-gate pressure setting, the spring force will be greater. This seems like another option to be able to run a higher % EBC vs wastegate pressure, without a dual port actuator.
Been doing some brain storming while I wait on my transmission. Doing a little measurement and math I was able to come up with graphs that show how and why a wastegate controller does what it does. These graphs may or may not explain it well, but take a look at the spreadsheet and play with the numbers some and you'll start to understand how spring pressure and boost pressure correlate to particular reaction by the controller.
So what you are looking at here is the force being applied to the wastegate flapper by the exhaust gas pressure in red graphed beside the force of the controller pulling on the rod in blue. The graphed scenario assumes we're in full boost mode with the EBC dumping off all the boost pressure off the top of both controllers. In the dual port example you have spring pressure and boost pressure forcing the actuator closed, so you can see the lines never cross so the wastegate would never open because as boost increases and exhaust gas pressure increases they are biased towards keeping the wastegate closed. The reason for this is that the controller piston is 1.4" in diameter and wastegate flapper is ~.905" depending how much you've ported the hole. Keep in mind that the exhaust pressure is normally 1.5 times higher than the intake pressure. Poor setups can approach 2 to 1. Playing with this ratio you can see that with the sizes I have I will still have a rate of rise that is equal or greater than the wastegate rise until a 2.4 pressure ratio. Clear as mud?
Using the EBC you could equalize the pressure top and bottom on the diaphragm defaulting to just spring pressure which in this example is only 2 lb's so I could run literally 1 psi of boost before the wastegate would start to open. So I litterally end up with an infinite range of boost pressures available at the click of a few key strokes.
On the single port example you're seeing the spring pressure only graphed at 15 lb's of force and you see the lines cross at just over 10.5 psi of boost. So this single port would open at that point and balance out a few PSI higher. The spring pressure's I've plugged into these calculations are just a swag to get and idea of "how" they work. The biggest take away I had from this is that with a single port you have to have a lot of spring pressure to keep the wastegate closed, but you may or may not have enough boost pressure available to open it so you end up with a limited range of boost available with an EBC.
Finally got the new trans in over the weekend and..........all that math was correct! I can now get "all the boost" and have some semblance of control over it. The bottom end of what the boost control can maintain is quite a bit higher than I would have thought, but that may just be a function of the internal waste gate not being big enough to bleed off enough exhaust to get all the way down below 150kpa. Just one round trip to work (~60) miles and I have it somewhat holding 175kpa all the way to redline. It's a little finicky yet, and it appears there is certainly a delay in when the EBC reacts to a boost mismatch, the controller reacts and the boost levels actually react. It's bad enough that the initial value tables are more important in 1st and 2nd gear than the PID parameters. In the upper gears the PID parameters do what they are supposed to and I was actually able to get it to oscillate from being too sensitive which is a welcome change from being lethargic.
I'm now firmly out of injector with the 440cc RX8 injectors with duty cycles north of 100% and the AFR's begining to lean out. I picked up some injector clinic 650's so I'll be tossing those in and re-tuning fuel. Not because I want to make more power, as I'm pretty darn sure I'm right on the ragged edge of what the rods can take.
yeah yeah, everyone has a favorite brand. They all just lop off the diffuser plate and match them out of large batches of injectors. With sequential in the MS3 I can balance fueling based on the testing that FIC does on each injector.
These were used and cheap, which checked the boxes I was looking for.
A bit late to this but FF does not modify the injector in any way. They do match them from large batches. But for $300 you get PnP and ev14 technology and accurate data for setting them up out of a new unmolested injector.
FIC does modify injectors. And if you've ever dug around Injector Dynamics website you would never consider buying from them. Used and cheap, you get what you pay for.
A bit late to this but FF does not modify the injector in any way. They do match them from large batches. But for $300 you get PnP and ev14 technology and accurate data for setting them up out of a new unmolested injector.
FIC does modify injectors. And if you've ever dug around Injector Dynamics website you would never consider buying from them. Used and cheap, you get what you pay for.
Huh......it's funny how the car idles fine my duty cycles are down to 75% and I still have mone left in my pocket. Tell me again how I didn't get what I paid for? And what exactly on a spiffy website is supposed to be obvious to me? This site prides itself on data and facts but when it comes to injectors brand loyalty becomes a data point. NONE of these guys make these injectors, FIC provides individual injector test results in affect showing their work so there was nothing to hide and I know exactly how much fuel each cylinder is getting. With this data tuning took all of 50miles of my commute to true up the VE tables, idle and part throttle was surprisingly close. Obviously my WOT area was a hot mess because the RX8 injectors were static and fuel control was out the window.
The injectors Bronson has are from Fuel injector clinic. The company mentioned on IDs website is Fuel injector connection.
Common mistake.
Fuel injector clinic injectors are great. And work fine. IDs are just a step higher, and their price reflects that. I wouldn't hesitate to use fuel injector clinic injectors at all.
You stated that all brands modify the injector. It's a general statement, I know, but it is not the case with FF which I thought warranted stating.
And on ID's website there are articles with clear references to FIC's work. You can choose to read it and choose to believe it or not.
So instead of new, matched, ev14 injectors for $300 you got something that works just as well for much less. It's great that you got what you wanted and not what you paid for. Props to you. Personally I am not that frugal. The thought of getting a set of used injectors that I wouldn't feel safe with unless I sent them in for cleaning (which would be $100 likely) just doesn't add up to me. And since I am not as handy at tuning to be able to monitor individual cylinder AFR to adjust each injector, I will just rely on the average AFR and trust a matched set of injectors is still matched down the line.
And while my car is N/A I just had a totally different experience tuning my car with bigger injectors. They were at 90% dc though so I guess not quite static. Idle and midrange was lean but WOT was close.
Ok, the reason I like FF injectors is because Nigel is a cool guy and is local to me, sort of.
Anyway, he first figured out how to make the gt500 injectors work well with our cars. Back when everyone was wondering about them. He did a bunch of R&D with Savington, if I am not mistaken. He figured out that the connector pins were too short and that they needed small spacers for the rail.
Now he offers a competitive kit which I have been running for over 20k miles and can run 12's in the 1/4 mile with. Any time he learned something new, he sent me the updated parts, no charge.
I finally got a chance to stretch her legs at an auto-x last weekend. The car did well with an 8th place overall out of 60 cars, my fun run times would have landed me in the top 5. It took a little getting used to the delay between throttle input and turbo spool up but I got the hang of it. On the street or track I don't think it'll be noticeable at all.
Number on the top right is MPH, Boost is directly below. 12psi is yellow, 13psi is red.
I also got a chance to really flog on it on some glorious back roads to and from the auto-x and no matter how hard I tried I couldn't get it to warm up over 190deg. Intake temps never went about low 90's with 60 degree ambient temps.I did finally get the oil temps up to 195 degrees on the outlet of the cooler.
Cool build and the autocross videos looked like fun. Makes we want an NB. I need to read post 102 when it's not so late but there's some good info here. Cheers
God I'm a cheap ***.......picked these used puppies up for a song. Previous owner had bearing issues within the first few hundred miles of use. I'll have the rods checked out, may need a resize or replacement but the CP pistons are worth what I paid for the whole set. I'm not in a huge hurry to get these in, ideally the stock bottom end will make it through a few track days and another half dozen auto-x events and I can build the forged bottom end this winter.
On the single vs dual port wastegate thing, I switched over to one back in 2012 and it worked great in my problems of losing boost at high RPM.
Car would make target boost pressure and then as RPMs went past 6000s, boost would drop off as the wastegate got forced open by exhaust gas pressure. Switching to dual port completely stabilized everything. Power went all the way to 7500 rpm instead of dropping like a rock past 6000.
Basically dual port lets you run less wastegate spring pressure and still have good control over boost.
I'm heading to Summit Point on July 1st and 2nd.......so the panic set in. I put together a punch list of things to get the car ready and got to work.
First I needed a seat back brace for the passenger seat, it's a sparco sprint but long out of date, so a seat brace is needed to be fully kosher.
I was also having fuel starvation problems at less than a 1/4 tank, little research here showed the short fuel sock I installed most likely was the culprit so I replaced it with an OEM unit.
I found a sloppy wheel bearing after the last auto-x so I just ordered a full set of hubs and bearings front and rear.
Those are dorman hubs, I wanted to press in ARP studs but luckily I found out here that the holes are not Miata spec. I drilled and reamed these to the proper size before pressing in the studs.
I also added some of the heat reflective insulation to the hood and master cylinder since I noticed the hood was getting mighty hot.
Finally I started worrying that the carbotechs wouldn't be enough for the power I was making with the puny stock size rotors. I fabricated some brake cooling ducts. You can read the full writeup here: https://www.miataturbo.net/suspensio...g-ducts-93718/
They'll be plenty of video of my track shenanigans....if any of you happen to be at the event stop by and say hi, I'll probably be fixing something and need a hand.
Success!!!! So my first track day was a great success. I was at Summit Point on the main circuit which has a good mix of miata tight technical sections and decent straits to stretch your legs as well. It was smoking hot (for the north east) at over 90 degrees ambient, asphalt temps were well north of 100 so it was great test for the cooling system. Believe it or not I'm a track newb....been wasting my time with auto-x for the last decade. I was in the green group so passing was limited to just the 3 straits with a point by. Luckily I still had some stiff "competition" in the group smattering of Miata, old beamers, GTI's, M3, M4, GT350, SS Camaro, and a pair of nearly fresh off the lot ZL1 camaro's. We were all learning our cars, the track, and generally how to drive fast. Kinda crazy to think I've been auto-xing for this long....and never really learned how to brake.
I tweaked the tune a bit before I went backing the boost down a smidgen to 11-12psi and pulling a few degrees of timing to be darned sure I kept detonation at bay. I also had a low boost table setup at 9-10psi on a switch in case I had heat issues. For some reason after the first session or two of the day the ECM switched to the low boost table, I'm guessing it has to do with the ground used for the switch input. I'm using a chassis ground, so I'll run a dedicated wire from the ECM. Past this, I had no problems with the car.
The results:
Engine Temp:
Absolutely amazing, the car never got above 200, and it wouldn't have even gotten that high if the thermostat would have been able to keep up with the temp swings. As you can see in this log the temps would swing up during the acceleration zones and the thermostat would open and the temps would dive into the low 180's. Plenty of cooling capacity, part of me wants a better way to regulate the water flow but I was watching some high lights of Dale Jr. crashing....again and I remembered it was very common in nascar to tape off the radiator inlet to balance temps with aero. I think I'll make a divider to guide more of the incoming air through the intercooler until the water temps stabilize.
Manifold air temp:
More good news here, I was only seeing 130 degree inlet temps at the peak when it was still boosting to 12 psi. It mainly hovered around 110-115 at 10psi and dropped much quicker than what I see on the street. With the divider to channel more of the air through through the intercooler I betcha I can improve on this quite a bit. Thoughts on these temps? Acceptable? should I have spent more than 80$ on this amazon special?
Oil Temps:
Happy here too, temps were steady in the low 200's peaking at 225 degrees. Keep in mind this is on the cooler outlet, some what regretting not putting the sensor on the inlet just to see how hot the oil actually gets so I'll know if I'm scorching it north of 300. I can't imagine I'm getting a 75 degree drop across the cooler.....we'll call this good.
Brakes:
They didn't fade......ducts worked great. I was a good 5 seconds off the spec miata track record but I was carrying way, way more speed than any miata should, and then slowing more than a spec miata would as well. I would say I was pretty hard on them. A more experienced friend blew through a set of DTC-70's in his vette over the two days, so the course was pretty hard on brakes. I was bleeding off speed from 125 to 45mph into turn one, and again from 100ish to 45 in 4. As a comparison a SM would be around 105-110 into 1 and maybe 80mph through 4. I did burn through ~40% of the carbotechs, unfortunately it was the last 40% of the pads so I was done with one session left. I had another set of pads, but I was burnt too, so I loaded it up while she was still in one piece.
The rest of the car performed well, the budget bilstein setup needed a bit more travel to cope with the mid corner bumps but they worked well with the RS4's and it was an unholy terror in the tight sections compared to some pretty serious hardware albeit with green hands at the wheel. I'll probably add some extended hats in the rear and raise the car slightly. Overall balance was great, I could make it push or loose at my will. Just need a little more stability over the bumps and it'll do well in the high speed sweepers.
Enough words, on to the video. This is one of my faster laps at 1:32, still quite a few mistakes here. I brake way to early for 1 and should carry another 10mph through 4 and possibly the same through 10....add in more boost and I think 1:28's aren't out of the question. Basically I need my ***** to "clank" not "tink".
This video shows the speed differential to the other fella's in the group, this Blue ZL1 is the only car in the group that passed me and I was reeling him in pretty good before he had heat issues. He could only get ~20 min out of it before it got uncomfortably hot. My buddies GS vette had the same issue, so it wasn't just the blower. The car was quick, and I got quite a few visits from other drivers to see "what the **** I had done to it"
Remember how I said I would get around to installing a brace on the intake manifold? Yeah should have done that...... Decided to do a boost leak check when I noticed my wastegate duty cycles were higher than they had been. Sure enough found a hairline crack in the heat affected zone right beside my welds on 3 of the runners. Interestingly enough they were all cracked on the bottom. I'll grind out the cracks and reweld, I'm in a hurry to prep the car before vacation and a track day when I get back so I may or may not get a brace fabricated. That would have sucked to have come apart in the first session.
05-01-2017, 08:17 AM
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