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The tuner I'll be taking the car to had access to a 2016 ATS-V calibration and he says it has 126 lbs/hr plugged in for the injectors.
If the engine/ECU package is anything like VAG powertrains, HPFP pressure should be reported back to the ECU, so your tuner may be able to look for it.
If the engine/ECU package is anything like VAG powertrains, HPFP pressure should be reported back to the ECU, so your tuner may be able to look for it.
I am using HPTuners and I can see both psi/load for the HPFP as well as psi for the LPFP. I have an analog gauge that I use to monitor the LPFP side at a glance and it has always correlated with the ECU. I doubt the LPFP will be an issue and I suspect he will not need a HPFP or injectors either unless he gets bit by the MAX_HP bug. Remember Ryan.. we did this for powerful, cheap and reliable spares!!!!! ;-)
Here is a snippet of a "going for broke" run with max boost at 7,200 RPMs. DW255 LPFP and stock LFX HPFP and injectors.
I asked the tuner to check HP pump stats in the calibrations for LFX vs LF4:
"The only thing I'm seeing is that it can (or at least does) operate at a significantly higher pressure thereby allowing even more flow from the larger injectors. it runs at 20mpa vs 15mpa on your setup under load."
15mpa = 2175psi
20mpa = 2900psi
So IF more fuel is needed the pump looks like a good option ($180 vs $480 for a set of LF4 injectors)
update: spoke to GPI who did the LF3 HPFP retrofit in that Gretchen guy's car. They don't have any notes on the Ferrari lash cap they used to make it work. They also mentioned the didn't feel it made much difference (although 650 whp seems to disagree with that).
I asked the tuner to check HP pump stats in the calibrations for LFX vs LF4:
"The only thing I'm seeing is that it can (or at least does) operate at a significantly higher pressure thereby allowing even more flow from the larger injectors. it runs at 20mpa vs 15mpa on your setup under load."
15mpa = 2175psi
20mpa = 2900psi
So IF more fuel is needed the pump looks like a good option ($180 vs $480 for a set of LF4 injectors).
Interesting! So if the "15mpa =2175psi" is the max for the stock LFX HPFP, then I am almost at 100% duty when at max RPM and the wastegate on full boost(~17psi). Hopefully, at the very least, my testing can help you focus your purchases to the ones that provide the greatest reliability and opportunity!
I SOOO badly want to go with a SC but the amount of fab work I would have had to do made it too hard to justify on my build. That and I was almost CERTAIN that you would go that way after your taste of the BIG HP boys tails at COTA! ;-)
I'd also like to add that on 17psi, the car hits plaid speed on the speedo!
I asked the tuner to check HP pump stats in the calibrations for LFX vs LF4:
"The only thing I'm seeing is that it can (or at least does) operate at a significantly higher pressure thereby allowing even more flow from the larger injectors. it runs at 20mpa vs 15mpa on your setup under load."
15mpa = 2175psi
20mpa = 2900psi
So IF more fuel is needed the pump looks like a good option ($180 vs $480 for a set of LF4 injectors)
update: spoke to GPI who did the LF3 HPFP retrofit in that Gretchen guy's car. They don't have any notes on the Ferrari lash cap they used to make it work. They also mentioned the didn't feel it made much difference (although 650 whp seems to disagree with that).
Keep in mind that was done before the ATS-V LF4 was out. Based on the screenshot of the video I'm 100% certain it is the LF4 HPFP that Overkill is providing with their E85 supercharger kit and it is a direct swap from what I could tell. The one in the video looks exactly the same as the one on ebay.
At some point there's only one way to really tell, and I want to try to have an option on hand when we get to dyno tuning if we find we need more fuel. So, LF4 pump ordered. Will test fit it on the spare motor when it gets here.
Interesting! So if the "15mpa =2175psi" is the max for the stock LFX HPFP, then I am almost at 100% duty when at max RPM and the wastegate on full boost(~17psi). Hopefully, at the very least, my testing can help you focus your purchases to the ones that provide the greatest reliability and opportunity!
I SOOO badly want to go with a SC but the amount of fab work I would have had to do made it too hard to justify on my build. That and I was almost CERTAIN that you would go that way after your taste of the BIG HP boys tails at COTA! ;-)
I'd also like to add that on 17psi, the car hits plaid speed on the speedo!
If so, there is are at least a few hp to gain just by upgrading the DI fuel system.
The required fuel amount is controlled by the air mass and the requested equivalence ratio. The start of the injection event is at say 50deg ATDC on the intake stroke at WOT in a fully warm condition and is defined by a calibration map. Due to the excessive pulse width, you are now well into the compression stroke before the end of injection. This isn't such a big deal with PI; hell you can run nearly 100% duty cycle without too much detriment. With DI the later you are injecting means the less time you have for the fuel-air charge to mix. I've seen a 15-20hp drop on a turbo 4 due to the injection event ending close to the ignition event. The mixing goes to **** and your combustion stability with it; you're essentially on the edge of misfire.
As a general rule of thumb, you want to get all your fuel injected by the end of the intake stroke, and even earlier if possible. There are also other issues this may cause, like the injector closing running into a knock detection window and causing false detection. Also keep in mind this affect worsens with engine speed. Your pulse width is the same, but your crankshaft rotational velocity is higher.
On a side note 15mPa seems pretty low. I could see running reduced pressure at lower engine speed, but 20mPa is pretty standard for a GDI solenoid injector at WOT.
Working on intercooler, routing, etc. for the past several days. Making my own endtanks, which is a first for me, but required with how tight everything is.
Filter comparison, old N/A intake vs. new filter. Much more bigger.
I may have missed it somewhere, Ryan - the upright in your radiator opening, is that just a shield for your air filter, or does it serve another function?
I may have missed it somewhere, Ryan - the upright in your radiator opening, is that just a shield for your air filter, or does it serve another function?
Yeah air filter shield. Added it when I saw how much the filter was getting pummeled by bugs, tire boogers and small pedestrians.Johnny @ NLR also mentioned that with enough air velocity it can actually pass straight through the filter and never go in the motor.
New config won't have the filter in the nose, as the intake is now offset, plus the tiny added effect of barely pressurized air in the nose becomes unimportant when you have boost. Not entirely sure exactly where it's going to be, there's not a ton of space for 3.5" tubing and that massive filter. Still working through packaging.
Currently working on the new resident in the nose. Lots of work, had to fab a new frame to carry the rad, intercooler, oil cooler, and rotrex cooler all nice and tight together. I dug through just about every brand's catalog for intercooler core until I found this Vibrant core that perfectly fits in this funky vertical config I dreamed up. Piping length is crazy short; ~15" from Rotrex to IC and ~17" from IC to TB.
If so, there is are at least a few hp to gain just by upgrading the DI fuel system.
The required fuel amount is controlled by the air mass and the requested equivalence ratio. The start of the injection event is at say 50deg ATDC on the intake stroke at WOT in a fully warm condition and is defined by a calibration map. Due to the excessive pulse width, you are now well into the compression stroke before the end of injection. This isn't such a big deal with PI; hell you can run nearly 100% duty cycle without too much detriment. With DI the later you are injecting means the less time you have for the fuel-air charge to mix. I've seen a 15-20hp drop on a turbo 4 due to the injection event ending close to the ignition event. The mixing goes to **** and your combustion stability with it; you're essentially on the edge of misfire.
As a general rule of thumb, you want to get all your fuel injected by the end of the intake stroke, and even earlier if possible. There are also other issues this may cause, like the injector closing running into a knock detection window and causing false detection. Also keep in mind this affect worsens with engine speed. Your pulse width is the same, but your crankshaft rotational velocity is higher.
On a side note 15mPa seems pretty low. I could see running reduced pressure at lower engine speed, but 20mPa is pretty standard for a GDI solenoid injector at WOT.
So... I have been doing a fair bit of research on this statement. I understood the logic as soon as I read your comment but I wanted to find the actual values. Seems the general consensus is that anything greater than 5.5ms injector pulse width on a DI engine is the point where you have exceeded the capacity of the injector, pump or both. I did a real quick log and it appears that the stock LFX pump and injectors run out of capacity at about the 8psi of boost range under WOT. Although it appeared I was keeping up with fueling needs, I am tapping out the fueling system and the ECU is pulling torque/power to keep things in check with the commanded AFR apparently.
Sorry to clutter up your thread Ryan, but hopefully this will put a bit of fact behind the theory for those getting into FI with the LFX. My advice would be to go ahead and put that HPFP on before you even take it to the tuner and see if the injectors can keep up while on the dyno.
That's great info, thanks. At this stage now I'm trying to spend more time in the shop making parts than sitting at the computer doing research, I can get lost in a black hole of searching and reading, but don't nobody got time for that right now. HPFP will go in before we go to the dyno.
In Miata terms, we're making good power. But we're the underdog by a huge margin against the cars we compete with. No doubt, we make the most with what we have, but with the largest Time Attack event moving to Circuit of the Americas where horsepower reigns supreme, I knew we needed to turn the wick up. We'll always be down on power compared to the other guys, but that doesn't mean we can't give David a bigger rock against Goliath. However, save for some transmission hiccups, reliability has been one of our strengths and I did not want to sacrifice that. I had an idea.
This didn't happen overnight. I've been working on the solution all year in the background.
A year ago, I placed a Rotrex on a box beside my spare motor, and got started:
The first time I took this C38-92 out of the box I realized the challenge I had ahead. I'm used to the C30 units used on Miatas, and had that size in my mind when I was initially looking at the space in the engine bay, placement, etc. The C38 is a behemoth. It would turn out that packaging would be one of the largest challenges at just about every step in this project.
In July I posted this teaser, focusing on the new rolling engine lift. Only a few people noticed the blower hanging on the side of the motor
That was after months of work on the bracket, and the final is actually version 3 after scrapping two prior. That gets expensive when you're cutting 7000 series aluminum, but it has to be perfect. Clearances are mere millimeters everywhere, and rigidity of the bracket is critical to avoid having belt issues.
The frame rail had to be cut substantially and reshaped, with care taken to add new internal structure to ensure loads from the suspension are still transferred through the frame rail appropriately.
The subframe also had to be cut.
Did the math on pulley sizes and picked a few final candidates to test. We will not be spinning the blower to its redline, no running on the ragged edge here. Then ordered lots of belts and worked out a suitable belt for every pulley:
The packaging challenges continued with the coolers. I needed an intercooler and a cooler for the Rotrex fluid in addition to the engine oil cooler. I also wanted the shortest charge piping possible, made a bit more complicated with the throttle body at center top of the V6 rather than on the side of an I4. Off the shelf intercooler options weren't going to work, I was going to have to make it. I chose a Vibrant core with the right dimensions for what I had in mind:
To hang everything in place I had to toss the old radiator mounts and make an entirely new frame to hold everything tightly together:
I’ve never made intercooler endtanks before. This project was going to give me a lot of practice on the TIG welder. Drew up and cut pieces to make up the endtank:
The top tank took a while with a tube hand notched mid-bend to merge into the curved tank:
Finished intercooler after quite a bit of welding.
Welding the tanks to the core was a next-level learning experience; you’re welding a butt-joint with the core quadruple the thickness of the endtank, and the core by its nature is trying to suck all the heat out of the weld as you go. Rather proud of how it turned out.
New coolers in new locations meant making all new lines:
On to the intake, and more packaging challenges. I did the math on filter size for expected flow. The filter I had was big for a Miata. The new filter is massive:
The intake tube for the C38-92 is 3.5” and that does not want to fit… anywhere.
More fun welding:
In terms of sensor and component locations, there was some debate about what locations would work best. I made a couple different configurations for charge piping to try the options:
Using a TiAL QRJ blowoff valve, configurable for either recirculating or vent to atmo. Which MAF sensor location we found worked best would determine which config we wanted, so I did both VTA and recirc setups:
The recirculating config uses a hard line that was fun to bend:
The Rotrex points the air inlet straight back, directly at the downpipe. So inevitably, the silicone bend is riiiiight by the exhaust. To give the coupler the best darn shot at nice long life possible, both coupler and downpipe are wrapped, and then separated by a titanium shield with a reflective layer on the hot side:
Crankcase ventilation becomes critical when adding boost. A direct injection engine really benefits from catch cans even naturally aspirated, so it had been on my to-do list for a while. Since this is a race car only I simplified things a bit. Eliminated the PCV, drilled out and tapped both valve covers, and ran lines to a pair of catch cans that vent to atmosphere. With so little space in the engine bay, I ended up placing the cans in the hole that the HVAC system pulls air from on a street car:
The fuel side is tricky. Direct injection can’t be easily upgraded with aftermarket parts the way a traditional fuel injection setup can be. Expecting that we might find we need more fuel than we could flow on the stock system, I preemptively bought a high pressure pump from the Cadillac ATS-V (which runs the twin turbo LF4 engine), to see if the pump would swap in on the LFX:
It is almost identical. The only difference is that the plunger is ~0.100” shorter.
After some measuring we felt pretty sure that the lowest point on the cam lobe that drives the high pressure pump was tall enough to maintain contact with the LF4 pump so we swapped it in on the motor in the car. That is not a fun job. Think coolant reroute but with the engine even closer to the firewall and more stuff in the way.
Colder spark plugs were in order, Brisk Silver RR14S:
It’s all a big paper weight without tuning. That is outside my wheelhouse, and I wanted someone who really knew their field and would give the car the time and attention it needed. For this I teamed up with UMS Tuning. I consulted with Tony through the final stages of the build to ensure everything was configured the way he felt would get us the best run at all things working smoothly. With everything done he made some tweaks to the calibrations of a few sensors on the old tune for startup. It fired first try and idled pretty well.
Pulled it out of the shop, first time sun hit the car since February!
Then loaded up for the 350 miles tow to Arizona to get tuned.
I'm sure you can hear my maniacal laugh from here! Beautiful work as always Ryan. I predict final tune to be..... 85% of max torque within 2k RPMs and a max HP of.....540 and it will be 100% glorious in that chassis!!!!!
07-30-2019, 11:06 AM
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