Lighter = Faster (RX-7 Build #2)

Lewis7789

Evan aka "Lady Hands"
Contributor
V
1995 MX-5, 2006 MZ5, 2001 Yamaha R1
Not gonna lie, I got goosebumps at the flame. Great numbers, man! Especially with your break in tune. That car is going to be SO much fun on track.
 
V
'86 RX-7 Base, '79 RX-7 GS
Nice numbers, what were you running for timing?
Very conservative. At WOT it's in the 20's. I figure I've got at least 10-15 degrees of advance to play with. This car should be making 190-200 whp. I just need to find dyno time to work on the timing.

Not gonna lie, I got goosebumps at the flame. Great numbers, man! Especially with your break in tune. That car is going to be SO much fun on track.
It backfires ALL. THE. TIME.

I took the car to the Tail of the Dragon this past weekend. Yes, track days will be fun! I just have to watch temperatures when I'm in a crowd. The Dragon is relatively low speed and when you're in a pack it's hard to find clean air to keep things cool. I was seeing oil and water temperatures consistently above 200 degrees at one point so I had to back off and shift into a higher gear.

I went to the Deals Gap Rotary Rally for the first time this past weekend. I've put over 1000 miles on the car in the past week AND NOTHING BROKE (well, one thing but more on that later). Sustained highway driving, short trips, low and high speed corners, triple digit speeds, etc - everything seemed good. I had an absolute blast and learned a ton. I even took home 1st Place in the "FC" category at the car show on Saturday! I learned my "break in" tune was actually pretty lean pretty much everywhere except idle and WOT. Closed loop control was doing a lot to mask the problem. I had a free afternoon so I took advantage of some of the knowledge in attendance and did some road tuning. IT'S SO MUCH BETTER! I think a lot of my transient throttle issues were because my map was lean. We turned off closed loop control and disabled the fuel temperature corrections and went about fattening up the fuel map. There's still some hesitation and a slightly lean tip-in but it no longer falls on its face when I mash the throttle. I also got a lot of advice on how to self-tune so I'm going to be doing a lot of that myself in the near future. It's pretty much limited to fuel right now since I don't feel comfortable playing with timing unless I'm on a dyno.

The general consensus is that my injectors are too far away from the intake ports on the engine. This is probably why my idle is rough compared to other N/A cars and why I've been having difficulty tuning the transient throttle. Even though the road tuning helped significantly I still think I'm going to move my injectors down to the stock primary location on the center housing. I'm going to try to avoid running secondaries at first. I came across a few people this past weekend with setups like this, even turbocharged, and they didn't seem to have any issues with only air going through the secondary intake runners. Defined Autowork's 4-rotor FD is running one injector per rotor and has the injectors as close to the intake ports as possible so that says a lot about this arrangement. The good news is I already have everything I need to make this change: injectors, fuel rail, various adapters, extra -6 AN line, and a bunch of AN hose ends. I'll probably need to make two new fuel lines although I'm hoping I can salvage the existing feed from the fuel filter. I shouldn't have to make too many fuel adjustments. Hopefully this will address my fuel-in-the-vacuum-lines issues too. This will make the engine look cleaner since the fuel rail and injectors will be hidden under the throttle body.

The bad: (1) my reverse lights aren't working. I know they worked before my trip last week but now they don't. I'm hoping it's just a bad switch or a broken/loose wire. The system isn't complicated: provide power and ground to switch and when the car is in reverse the switch closes the circuit. I haven't had a chance to inspect the switch yet. (2) my suspension is VERY noisy in the rear. It squeaks, pops, clunks, etc. I noticed the squeaking before the trip and I'm sure it's the rear sway bay bushings again. I'm going to try the Teflon tape trick next. As for the other noises I first noticed them after running the Dragon on Friday. I need to get the car in the air to make sure nothing has come loose or broken. (3) My exhaust SUCKS from the manifold back. It bounces around, hits the bottom of the car, falls off its hangers, etc. I'm getting a new system fabricated as soon as I save up the funds needed. (4) my hatch leaks. The car car rain for the first time and the rear window leaks despite the weather-proofing foam we used. I think there are some small gaps near the reinforcement bars.

In other news I've committed to reinstalling some of the emissions equipment. I'm sick of the garage smelling like gasoline all the time and it wafting into the housing whenever I open the door. I'm going to put the charcoal canister and PCV back in. The RX7 uses a slightly more complex PCV system but I think I have a way of making it work that involves a few more vacuum fittings.
 

chuyler1

goes to eleven
Moderator
V
2013 CX-9
Great update! Wish I could have made it down to DGRR. It sounds like you learned a lot.

Before you go moving the injectors, I think you should put in a few hours tuning what you have with your new found knowledge. If you look at a lot of high end builds you’ll see a variety of injector locations. Having them in the center housing certainly will improve idle, but keep in mind that these cars can run just fine on carburetors installed right where your injectors are. Your throttle bodies might be a little large in comparison to the typical side-draft but otherwise there is no reason getting the transient numbers right shouldn’t fix the hesitation you have.

I say this of course, but I’m still having the same issue with my truck. I learned a few things from asking around but I just haven’t had the time to get out there and try it. My REPU is boxed in and I’ve been focusing on my 1st gen that I take to track days and an AW11 MR2 I’m restoring for my wife.

Anyway, if you’re dead set on moving the injectors, I’d suggest instead getting some small injectors for the center housing and keeping your big ones in the throttle body. The ECU should support staged injection which will use the small ones for idle and cruising, but then switch to the bigger injectors when more fuel is required. The longer distance for the secondary injectors will allow for better atomization at wide open throttle. And the smaller primary injectors offer better control at low load demands. This is something I am considering for my 1st gen when I put my new street ported 12a in.
 
V
'86 RX-7 Base, '79 RX-7 GS
I do have a pair of ID725s that came with the FFE primary fuel rail kit. I've been trying to avoid staging, if possible. It's added complexity and I don't think I need it unless I run much smaller injectors all around. The two ID1000s I have right now are capable of the low duty cycles needed for idle and flow enough to meet my current power needs. Your atomization comment makes sense to me but pretty much everyone I spoke to said you want the injectors as close to the intake ports as possible. Defined Autowork's peripherally-ported 4-rotor has four ID1000s in the intake manifold right before the flange to the engine. The R26B also had the injectors close to the engine. Here's what the SAE paper on the R26B had to say:

(3) PERIPHERAL PORT INJECTION
On engines preceding the R26B, an air funnel injection(AFI) was used in which the injector was located upstreamin the induction system to ensure good steady statedriving performance. Upstream injection caused adelay in fuel delivery to the combustion chamber, makingit difficult for fuel delivery to keep up with the fast chargingairflow in transient periods. This would inducethe air/fuel mixture to alternate between over-lean orover-rich, resulting in misfire and, therefore, temporarydrops in torque. With previous engines, this problem inacceleration was solved by such methods as increasingfuel delivery by determining the level of accelerationbased on change in throttle opening. Therefore, a slightmixture enrichment was allowed where acceleration waspredictable. Such compensations proved considerablydisadvantageous to driving fuel consumption.For the R26B engine, the fuel injection system adoptedwas peripheral port injection (PPI), as illustrated in Fig.14. The injector is now placed close to the intake portopening in the trochoid chamber. This layout minimizesthe fuel delivery delay, thus improving throttle response. Another benefit of PPI is considerable improvement infuel consumption in actual driving. This is ascribable toenhanced air/fuel ratio controllability achieved and theresulting expanded fuel-cut zones.

Source: http://www.rotaryeng.net/Mazda_R26B_US.pdf

I mean, that sounds pretty much exactly like what I'm fighting, doesn't it? Maybe there's a difference when it comes to side intake ports like we're discussing here. I've reached out to a couple other knowledgeable rotary tuners to see what they think.
 

chuyler1

goes to eleven
Moderator
V
2013 CX-9
Keep in mind a) the computing power they had in 1991 vs what we have today with stand alone ECUs and b) the progress that has been made with accuracy of fuel injectors, map sensors, and throttle position sensors.

I have no doubt it is more efficient to have them close to the port, hence the progress made toward direct port injection piston engines and the increase in fuel economy...but I still feel you can gain a bit at high RPM wide open throttle with them mounted further back.

In fact, study the Renesis engine. Two injectors for direct injection on the primaries. 4 more further back to allow for more mix time, of course they aren’t quite as far back as yours I did read on the Adaptronic forum that they found significant gains after messing with the staging configuration. Using the primary RX8 injectors until they reached 90% of their full duty cycle yielded less power than kicking on the secondary injectors sooner. I don’t remember the exact percentage they went with but the explanation was it was better to mix the fuel and air more evenly across the ports once they were all open.

The earlier generation rotaries made due with just two injectors, but they also made less power. So for me, I think I’ll weld bungs to my primary runners (since I don’t have ports on my 12a center iron) and put two injectors there, and two more in the throttle body and see how that works out.
 
V
'86 RX-7 Base, '79 RX-7 GS
I'm not convinced staged injectors are the result of the quest for more power. Mazda uses smaller injectors overall. Probably for a smooth and stable idle and acceptable fuel economy and emissions. The GSL-SE ran two 680 cc/min injectors. The N/A FC's ran four 460 cc/min injectors. What I could find on the RX8 was even smaller in the 290-380 cc/min range for all six injectors. There's an obvious trend. I don't think the R26B was concerned too much about a smooth/stable idle or emissions. It was built first and foremost for power and torque and then fuel consumption in an endurance racing environment. I've built my FC closer to the intent of the 787B than a factory car. Power and torque are the most important. Fuel economy and emissions are the least. Also, it wasn't until the last 10 years or so we had injectors like the ID1000 that can flow significant amounts of fuel but also operate at low duty cycles. I'm happy with a stable idle at 1000 +/- 100 RPM and so far I'm nowhere near 85% duty cycle on the injectors at maximum throttle and engine speed. It's likely staging injectors would improve the efficiency of the car but with added cost, complexity and risk. It would make for a good science experiment though.

I confirmed my reverse switch is bad. Although I get continuity across the pins when the switch is closed it doesn't work on the car. I tried this both with the switch installed in the transmission and by manual depressing it myself outside. Mazda doesn't give a range of acceptable resistance values but I'm guessing mine it too high. I've confirmed the rest of the system is good because the lights come on when I jumper the pins on the harness side of the switch. Oh well, new switch and washer ordered.

More bad news: (5) the transmission is in sorry shape. Gear oil appears to have been leaking from the shifter turret, dripping onto the driveshaft and getting splattered all over the underside of the car. I pulled the shifter and the fluid in there looks bad. It's gray/black and has low viscosity. It doesn't smell like normal gear oil either. I checked the oil level before my trip two weeks ago and everything looked good at the oil fill port. A transmission rebuild is definitely next in the order of business. (6) the inner CV joint on the passenger's side axle appears to be leaking based on the pattern of splatter nearby. I don't see any tears in the boot and I haven't heard any noise but it looks like a rebuild is in the future. (7) I found some evidence of coolant leaking from the lower radiator hose. I tightened its clamp some more and hopefully that fixes that. (8) it does look like I've got a couple small leaks around the oil pan. Not enough to drop onto the floor but enough to wet the studs. I cranked a few of them a bit to see if that'll help.
 

chuyler1

goes to eleven
Moderator
V
2013 CX-9
According to my research the RX8 has two 290cc that go to full capacity just under 4,000RPM and are the only ones used for idle and cruise. Then it has 4 380cc injectors, two in the primary ports and two in the secondary ports but they never hit full capacity. The concept is that you get a better spray pattern and fuel efficiency out of a small injector close to the port...but you make the power with a location further back. If this wasn't the case, I'm not sure why Mazda would have continued placing injectors in the manifold. They would have just moved them to the end plates.

If you are dead set on moving the injectors, you should at least be considering one per port, 4 total.

Here’s why:

The center plate injectors work great on a stock motor and intake because at low loads, the secondary ports are closed and the injection point is high velocity of the only air going into the motor.

With your intake, you cannot close the secondary ports so the center injection point is roughly half the velocity it would normally be and only half the air going into the motor (or less depending on how the motor has been ported).

It may still solve the transient issue, but at higher RPMs you’ll make less power. So before you tear apart the car again, spend a little more time with those transient settings. It likely just needs more fuel and/or a longer burst. As I said above, lots of people race side drafts and down drafts, Atkins sells a complete kit with injectors not that much closer to the ports. It’s all in the tuning.
 
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V
'86 RX-7 Base, '79 RX-7 GS
I've thought about that. The examples I've been using have been peripherally-ported engines, which only have one intake port per rotor, so my case is slightly different. Unless you have variable-length runners or staged ports there will always be a trade off between low and top end power. It's always a fight between airflow and velocity. Not wanting complexity, I've settled for top end. To make up for the loss of low end velocity I've increased air (and fuel) flow and changed port timing at the expense of idle quality, fuel consumption, etc. What you're describing is conservation of mass and it's my low end power that's suffering not the top end. That's due to my manifold design not the injector position. For a given mass flow of an incompressible fluid its velocity will decrease if area is increased (I'm ignoring slight changes in density due to changes in intake temperature along the length of the runner). We designed my intake manifold to account for this. My manifold runner is large after the throttle body but decreases in diameter proportional to the port size at the split. Each port takes its share of the air-fuel mass and since the intake diameter is reduced, velocity should remain constant. Ideally, for a given engine speed, my intake velocity is constant from the throttle butterfly to the engine for both ports. To your point, if I could close the secondary port at low engine speeds I would increase intake velocity since the runner diameter is reduced for the same mass flow through the throttle body. This would give me more low end power/torque at extra cost and complexity.

I'm still going to get a fuel map completed for the current arrangement. You are right in that my setup really isn't any different from an old school DCOE setup. There's no reason I shouldn't be able to make it work. I just keep coming back to the R26B SAE paper. Mazda didn't make any power claims regarding port versus throttle body injection but noted an improvement in throttle response. Even with the fuel and transient throttle tables properly tuned I'd imagine port injection would have better throttle response. Perhaps I'll run each setup on a dyno to figure out which makes the most power in the end. I imagine the fuel map won't be too different between throttle body and port injection. In the end I think it's going to come down to whether atomization plays a significant role or not.
 

chuyler1

goes to eleven
Moderator
V
2013 CX-9
I just keep coming back to the R26B SAE paper. Mazda didn't make any power claims regarding port versus throttle body injection but noted an improvement in throttle response.
I guess, just keep in mind that paper pre-dates the Renesis engine by more than a decade and it does clearly state they could overcome it, but at the expense of fuel economy. Everything they learned from their experience racing eventually trickled down into the RX8.
 
V
'86 RX-7 Base, '79 RX-7 GS
I've done the unthinkable. I've actually ADDED emissions equipment back in the car. I now have a working PCV system! I'm using the PCV valve and general system structure from a FD RX7. The goal was to reduce the amount of condensation I was getting in the crank case with just a vented catch can. Now this water/oil vapor gets actively drawn through the catch can and into the intake. Oddly, the car doesn'y seem to idle or drive any differently. I figured it would have idled a bit higher and drove a bit leaner with the extra air source. The next time I have the car running I need to actually confirm I'm drawing vacuum through the PCV valve...

I also reinstalled the stock charcoal canister and picked up an electronic purge valve from a FD. I'm trying to get a working evaporative emissions system to reduce the gasoline smell in the garage a bit. The evap system gets tee'd into the PCV system after the PCV valve. I don't have it setup yet. The FD purge solenoid requires a driving frequency and duty cycle to operate. I've setup two of my previously unused ECU outputs to drive the system. The first one closes a relay when the engine is warmed up and closes the circuit to the purge valve. The second controls the frequency at which the valve opens and closes based on engine speed and manifold pressure. The plan is to close the relay at 180F and operate the solenoid between 1500-3500 RPM at low-to-medium engine loads (-6 psi vacuum and lower) at duty cycles of 30-70%. From what I have been able to find this is how the stock FD system works. The only unknown is the base frequency of the solenoid. I'm going to start at 100 Hz and go from there.

Pictures later...
 
V
'86 RX-7 Base, '79 RX-7 GS
I wish we had the same ECU so we could trade notes a little better.
I'm running into a couple issues:

1. It almost seems like every time I start the car it wants to run a little differently. I've been trying to be better at doing my tuning around the same time of day in the same kind of weather to avoid atmospheric effects. I essentially started over yesterday redoing the no-load cells up to 6000 RPM. It's a little wonky because my engine pulls less vacuum at idle than it does elsewhere. Normally, I'd use Haltech's "quick-tune, all" function, which not only adjusts the current cell but also those in the next higher RPM and MAP cells. Instead, with no load I have to adjust the current cell and next higher RPM but next LOWER MAP cells. I did this and got a more consistent-looking curve for the no-load conditions.

2. I really need someone to quick-tune some of the more stable points while I'm driving. My general understanding is for a given engine speed you have the no-load case and then some case with a high load. When those two cells are squared away you interpolate between them and then make small tweaks as necessary. Since I'm by myself I'm datalogging and reviewing the results afterward. I have to make a judgement call on how to adjust the load case. I had a bit of a lightbulb moment last night and made some significant changes to my tune. Hopefully I'll get a chance to go out tonight and check the results.

How much do you vary your target AFR? I'm curious if I'm making this harder for myself by having a somewhat complicated target AFR table. The base tune I got from Chris Ludwig was basically 13.0:1 everywhere below 2500 RPM. From 2500-5000 it's stoichiometric at low-medium engine loads and starting at 50% throttle tapers to 13:1 at WOT. Above 5500 it starts to taper down with RPM to where it's 13:1 or less above 9000 RPM at all load conditions. My current target is based on some suggestions I got from a tuner at DGRR. It's similar to Chris's but converted to a MAP-based load. It's 13.5:1 below 2000, 14:1 from 2500-7000 and then tapers down to 13.5:1 at 9000 for low loads. Above -10 psi MAP the AFR target decreases linearly to 12.5:1. For <2000 and >7000 the 12:5 target comes on sooner and I just hold that for the remainder of the row.
 

chuyler1

goes to eleven
Moderator
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2013 CX-9
So before I do anything to my 85 RX7 I installed an Innovate Motorsports dual AFR gauge. The motor can Nikki carb are bone stock so I used it as a reference point for the truck. Below is what I came up with. The only exception is that 0-25% MAP and 3000-7000 RPM could be bumped to 15. These are the readings I’m getting on my 1st gen. Idles at 13.7, cruises at 14.7, and punching it will drop to low 13, occasionally high 12, but I’ve been told max power on N/A can be achieved at 12.5. Now to be clear, these are averages +/- about 0.5, you’ll never get a steady flat reading, so if you are close, let closed loop handle the last bit.



As for getting different readings at idle, keep in mind that intake air temp is probably messing with you unless the hood is open. On a warm day, get the car warmed up then park it. Watch the AFRs and have the air temp trim table open (I assume you have something of the sort). As the temp rises in the engine bay, adjust the trim a little. Or you could install a cold air intake. I still don’t have mine setup right and I noticed it in traffic when the intake temp shot up to 100 before the e fan kicked in to blow some cooler air in.

Another thing it could be is the injector dwell. If you keep changing the values, check the voltage in the log. There should be a table to adjust how long the injectors open based on voltage. Injector Dynamics probably provides the correct settings for the table, but you can also tweak it by getting the car stable at idle, then turning on accessories until the voltage drops, and adjusting the table to fix the AFR.

In my last log, I noticed something new. When I punch the throttle, the portion of the log that matches with the accel pump (transient correction) is fine, but it’s a second after that where I get the lean condition. I think it could be fuel starvation. I don’t have a vacuum line connected to the FPR, so that’ll hopefully be a quick fix, if not, I will have to rethink my fuel lines, pump, and filter setup.
 
V
'86 RX-7 Base, '79 RX-7 GS
So before I do anything to my 85 RX7 I installed an Innovate Motorsports dual AFR gauge. The motor can Nikki carb are bone stock so I used it as a reference point for the truck. Below is what I came up with. The only exception is that 0-25% MAP and 3000-7000 RPM could be bumped to 15. These are the readings I’m getting on my 1st gen. Idles at 13.7, cruises at 14.7, and punching it will drop to low 13, occasionally high 12, but I’ve been told max power on N/A can be achieved at 12.5. Now to be clear, these are averages +/- about 0.5, you’ll never get a steady flat reading, so if you are close, let closed loop handle the last bit.
Okay, that's pretty cool. What I have isn't too far off that. I'm targeting a little richer at idle and the low-to-mid range. I can live with that since my engine seems to like runner richer in general. Any above 13.5 or so below 2000 RPM is unstable. Ideally I'll get within +/- 0.1 of my target. My two oxygen sensors never read the same so I'm always averaging them anyway. But yeah, once I get close I'll call it "good enough" and turn on the closed loop control again.

As for getting different readings at idle, keep in mind that intake air temp is probably messing with you unless the hood is open. On a warm day, get the car warmed up then park it. Watch the AFRs and have the air temp trim table open (I assume you have something of the sort). As the temp rises in the engine bay, adjust the trim a little. Or you could install a cold air intake. I still don’t have mine setup right and I noticed it in traffic when the intake temp shot up to 100 before the e fan kicked in to blow some cooler air in.
Yeah, I noticed this after my first attempt when I saw the IAT reading over 160F. In general I turn off all the fuel corrections when doing my tuning but the atmospheric effects are still there. The last couple attempts I parked in the shade and opened the hood, which generally kept the IAT at or below 140F.

Another thing it could be is the injector dwell. If you keep changing the values, check the voltage in the log. There should be a table to adjust how long the injectors open based on voltage. Injector Dynamics probably provides the correct settings for the table, but you can also tweak it by getting the car stable at idle, then turning on accessories until the voltage drops, and adjusting the table to fix the AFR.
Yeah, I have the table from ID uploaded. My only "accessories" are the electric fan, lights, and interior blower. I have noticed when something is on and the idle drops a bit the car does run a bit richer despite my fuel settings being identical in that area. Mayb you're onto something there.

In my last log, I noticed something new. When I punch the throttle, the portion of the log that matches with the accel pump (transient correction) is fine, but it’s a second after that where I get the lean condition. I think it could be fuel starvation. I don’t have a vacuum line connected to the FPR, so that’ll hopefully be a quick fix, if not, I will have to rethink my fuel lines, pump, and filter setup.
So you're running a constant fuel pressure right now? I can't remember what size injectors you're running but I can't imagine you're max'ing out your system. What are your duty cycles in that situation? Haltech has a "decay rate" that can be adjusted. I'm sure Adaptronic has something similar. Perhaps your enrichment events need to be longer. On that subject I actually have my transient throttle enrichment disabled. Interestingly enough the car doesn't drive THAT much worse. I turned it off mainly so it wouldn't interfere with my datalogging. I'll turn it back on with the closed loop control when I get the fuel dialed in.
 

chuyler1

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2013 CX-9
So you're running a constant fuel pressure right now? I can't remember what size injectors you're running but I can't imagine you're max'ing out your system. What are your duty cycles in that situation?
Yeah, constant 35psi. 4x 440cc injectors, not staged. I don’t think I’m maxing the system, but I think the FPR isn’t reacting fast enough to the change in demand. If I slowly push the throttle in, it is fine, but any rapid change leads to lean or rich conditions. I could probably hook up a fuel pressure sensor to confirm, but I’ll just try hooking up the vacuum line first.
 
V
'86 RX-7 Base, '79 RX-7 GS
Yeah, constant 35psi. 4x 440cc injectors, not staged. I don’t think I’m maxing the system, but I think the FPR isn’t reacting fast enough to the change in demand. If I slowly push the throttle in, it is fine, but any rapid change leads to lean or rich conditions. I could probably hook up a fuel pressure sensor to confirm, but I’ll just try hooking up the vacuum line first.
That fuel pressure seems low to me. Stock FC injectors are 460 cc/min and the fuel pressure regulator uses a vacuum reference with a base pressure of 34-40 psi. I don't know the rate of the regulated pressure relative to its source though. I'd think you're making more power than a stock FC so you'd want more fuel. My base fuel pressure is 45 psi and I'm using a 1:1 regulator so I have 38-39 psi at idle, which is around 4% duty cycle on my 1000 cc/min injectors (actually around 1035 cc/min at 45 psi).
 

chuyler1

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Moderator
V
2013 CX-9
That fuel pressure seems low to me. Stock FC injectors are 460 cc/min and the fuel pressure regulator uses a vacuum reference with a base pressure of 34-40 psi. I don't know the rate of the regulated pressure relative to its source though. I'd think you're making more power than a stock FC so you'd want more fuel. My base fuel pressure is 45 psi and I'm using a 1:1 regulator so I have 38-39 psi at idle, which is around 4% duty cycle on my 1000 cc/min injectors (actually around 1035 cc/min at 45 psi).
I think I lowered it early in my tuning process because I was seeing a maximum of 50% duty on the VE table. Of course now I only get to 62% on the table. I’m definitely going to add the vacuum line and make sure at open throttle I get 45psi since that’s what the injectors are rated at. I know it’s going to mess with the whole table, and the truck drives now (as long as I go easy on the throttle), so I need to wait until I have a few hours to retune it.
 
V
'86 RX-7 Base, '79 RX-7 GS
I think I lowered it early in my tuning process because I was seeing a maximum of 50% duty on the VE table. Of course now I only get to 62% on the table. I’m definitely going to add the vacuum line and make sure at open throttle I get 45psi since that’s what the injectors are rated at. I know it’s going to mess with the whole table, and the truck drives now (as long as I go easy on the throttle), so I need to wait until I have a few hours to retune it.
That reminds me; I really need to check my duty cycles at higher engine speeds/loads.

What kind of fuel pressure regulator are you using? I assume it's a 1:1 rising rate aftermarket unit. If so, just increase the fuel pressure without the vacuum line to 45 psi and then connect the line. You're still stock port so you likely pull more vacuum than I do. Ideally your idle and cruise fuel pressures will be in the 35-38 psi range so you shouldn't have to change much there. Don't forgot to change the fuel pressure reference setting if Adaptronic has one. In the basic setup in my Haltech I have the choice between "constant" and "MAP-referenced" fuel pressure.
 

chuyler1

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2013 CX-9
That reminds me; I really need to check my duty cycles at higher engine speeds/loads.

What kind of fuel pressure regulator are you using? I assume it's a 1:1 rising rate aftermarket unit. If so, just increase the fuel pressure without the vacuum line to 45 psi and then connect the line. You're still stock port so you likely pull more vacuum than I do. Ideally your idle and cruise fuel pressures will be in the 35-38 psi range so you shouldn't have to change much there. Don't forgot to change the fuel pressure reference setting if Adaptronic has one. In the basic setup in my Haltech I have the choice between "constant" and "MAP-referenced" fuel pressure.
I am using a Fuelab regulator. Left dead ends at the fuel rail, right comes from stock hardline. Bottom overflows to stock hardline.



Adaptronic does have a fuel pressure setting. I haven’t touched this table. Oddly, the fuel pressure and the mode is disabled when I select “deadtime / flow” so I didn’t mess with it. But if I change the injector type to ID1000 I can change the values, switch back to “deadtime / flow” and it stores it. So maybe I just need to try a fixed fuel pressure option instead of manifold ref. You can see in photo the settings are disabled. Anyway, thanks for pointing this out, I have something new to mess with!

 

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