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infernosg
infernosg New Reader
9/15/20 10:06 a.m.

In reply to Don49 (Forum Supporter) :

Mine is still in the stock, angled configuration. I've thought about making some brackets to make it more upright, but that would resuly in a cascade of other changes I don't want to mess with for the moment. I'm trying to get one more event in this year. VIR is likely out of the question due to schedule conflicts but there is another event at Dominion in November. I'm currently waitlisted but if I get in it'll be a good test of how lower ambient temperatures affect my temperatures.

Right now I think the biggest issue is the inlet and exit of my oil cooler duct. The inlets are sized to be 20-25% of the heat exchanger area, which seems to be the recommended area. However, looking at the front of the car I can see where the oil cooler area inlet area is actually smaller with everything installed.

I'm wondering if I'm getting some boundary layer effects from the split and the bumper cover that's reducing flow to the oil cooler. It's also possible the split is deflecting at speed, reducing area even more. This Winter I plan on raising the split a little more and adding a stiffening rib across the front or a vertical strut. I may even cut out a small area of the bumper cover. Someone suggested cutting out the bar between the frame rails to increase flow to the radiator but I'm not sold on that. I can leave the ends in place so I don't lose the oil cooler mounting points but I don't know what losing that bar will do to chassis rigidity.

The other thing I'm going to address is the area behind the oil cooler. In this picture of the duct out of the car you can see the exit from the oil cooler is open to the inlet of the radiator.

As you can see the split ends at the oil cooler. I'm thinking the slightly higher pressure in front of the radiator is reducing flow through the oil cooler. My solution is to extend the split all the way to the radiator. This does mean that heated air from the oil cooler will then be passing through the radiator. The only way to avoid this would be to cut out the bottom of the duct and force the heated air from the oil cooler out through the bottom. However, I've read that ducting out the bottom of the car can increase front end life, which is definitely something I don't want.

infernosg
infernosg New Reader
9/15/20 3:25 p.m.

In reply to Don49 (Forum Supporter) :

Also wanted to respond to your shifting comments. I'm nearly certain your correct. The shifter springs are all less than 2 years old so no issue there. On my last run of the day I had a REALLY hard time getting it into the correct gear. Wouldn't go into 3rd so I tried to just bypass it and go into 4th and I kept ending up back in 2nd. I'm definitely holding the lever to the left slightly. It's a short-throw shifter with a 4" extension to it doesn't take a lot of movement to move between the gates. I need to work on methodically moving the lever out of 2nd, letting it center itself, then moving it up into 3rd. It's definitely a stress/fatigue problem. I had no issues in the clip I posted, which was from an earlier run in the day, but I got progressively worse as the day went on.

infernosg
infernosg Reader
1/26/21 1:36 p.m.

Four months since my last update. Unfortunately, the reason for this is little has happened. I ran my last track day in September and with no events in the near future there wasn't much motivation to work on the car. I briefly switched my attention to my 1st gen but got quickly burned out by a stupid brake issue that ended up taking the better part of 3 weeks to figure out. So other than driving the car once every 2 weeks there wasn't much going on until this past weekend.

What happened this past weekend? As a late Christmas/birthday present to myself I scheduled some dyno tuning time with a shop who knows what they're doing. Though the car has been running for 3+ years I'd say the tune was only 80% or so. I've been running safe timing and while the low/medium load/RPM areas of the fuel map are pretty dialed in I knew the higher load/RPM areas were conservative. I was too oblivious to take any pictures/video of the car during the session so this is all I have at the moment:

I went to a pretty well-known shop in VA and there was plenty of footage taken. I'm told there will be some YouTube content in the near future. After 2 hours of WOT pulls we went from this:

to this:

This was my first time on a Mustang dyno and I admit I don't understand all the numbers. The curves show I started at 233 hp and 160 ft-lb and ended with 251 hp and 168 ft-lb. However, the "power curve test results" say I started with 241 hp and 163 ft-lb with "WCF" (weather correction factor?) and ended with 262 hp and 170 ft-lb with WCF. It looks like Mustang dynos make a lot of assumptions about the vehicle and one thing I did notice is that my car's entered weight was 3250 lb when it's really 2500 lb with driver. I don't know how that affects the results. Regardless, both sets of numbers show a max increase of ~20 hp and ~8 ft-lb with improvement everywhere. The delta is all we care about, right? So far I've only just driven the car back from the shop so I haven't had the chance to really test if the difference is noticeable. So what did I learn from all this?

-I was leaving a lot on the table with conservative fuel and timing. We leaned out the fuel map, advanced total timing and increased the split between leading and trailing ignition timing.

-I'm running out of fuel. Adding fuel above 8000 RPM wasn't reducing the air-fuel ratio so I must be maxing out the duty cycle. I'm running 2 ID1000s with 45 psi of fuel pressure. Messing with a few online calculators tells me 2x 1000 cc/min injectors is enough fuel for ~320 hp. Assuming 20% drivetrain losses means my 250 hp at the wheels is ~313 hp at the crank. Seems plausible and I have options. I can increase fuel pressure and run 50+ psi. ID's data suggests just going from 45 to 50 psi will give me another ~100 cc/min of fuel. I could swap to 2x ID1300s I've had sitting around in the garage. +600 cc/min is a massive bump in fuel so I'd drop the pressure to 40 psi. Both provide the extra fuel I need at high RPM but both will have issues with low duty cycles at idle. My idle duty cycle is already in the 3.5-4% range. The only way around this is to go to a staged setup with smaller primary and larger secondary injectors. I've been avoiding this complexity but maybe it's time to give in. A benefit is placing the primaries closer to the intake ports would improve idle stability and low RPM transient response.

-I still have restriction somewhere. It starts to pull slight vacuum at WOT at higher RPM. This tells me I either can't get air in or exhaust out fast enough. This is not new. This has persisted despite the new exhaust and intake setups. The guys at the shop think my throttle bodies are undersized at 2x 50 mm but I had this same problem with my old 2x 55 mm setup. I think it's more likely the runners in the intake manifold or in the ports on the engine are the cause. Not much I can do about this.

-I confirmed my air box isn't hurting power. We did two back-to-back runs early on with and without it and the results said I actually lost a little power without the air box. 

-The starting numbers were pretty close to my last results from Summer 2019 when the car put down 241 hp and 160 ft-lb on a dynojet. This makes me pretty confident my car is putting down ~250 hp to the wheels, which is damn good for a street ported, naturally-aspirated 13B. This puts my weight-to-power ratio around 10 lb to 1 hp with driver.

infernosg
infernosg Reader
3/4/21 3:22 p.m.

1+ month bump. Here's the official video from the last dyno session. Ignore me and focus on the car...

I took a break from the car for most of February. We had an unusually cold period here so I didn't spend much, if any, time in the garage or driving the car. Lately we've had some ~60F days so I've been driving it a few times, working on the part throttle fuel map. I'd say the tune is 95% there. Where the fuel table isn't 100% closed loop control can handle and I'm working on refining that and transient throttle. It's a little tricky finding the optimum control settings for an engine with ITBs and big ports.

I've already committed to two track nights. I'll be back at Dominion in April and May will be my first time driving at VIR. Can't wait, but that means it's time to get to work. In addition to continue sorting out the tune I need to do the usual maintenance (fluids, check bolts, bearings, alignment, etc.) and I'll be making some tweaks to my radiator/oil cooler ducting. I've also determined I'm not as hardcore as I thought I was - I'll be replacing the delrin engine and transmission mounts with some polyurethane ones. They're still 95 durometer but hopefully the car won't be rattling my fillings out over 8000 RPM anymore.

crankwalk (Forum Supporter)
crankwalk (Forum Supporter) GRM+ Memberand SuperDork
3/4/21 3:29 p.m.

I saw this on the Angel Motorsports channel and was excited to see this car. Great numbers with the Mochi tune. ;)

infernosg
infernosg Reader
3/18/21 9:58 a.m.

Well, track season prep is underway. Ordered all new fluids and filters and it looks like I'll have everything by next weekend. That gives me about 2.5 weeks to get everything ready for the first track day of the year. Last week I tinkered with the suspension. Back in January I ordered a new set of AWR rear camber links. Around this time last year I decided to ditch my original AWR camber links and try a different product. While I like the design of the other camber links they're lack of adjustability was a big downside.

"Old" links:

Note the awesome spherical bearing design to avoid binding. Here are the "new" links:

I like that they are adjustable but wish there were some way to incorporate spherical bearings. The grease fittings are a nice touch though. I've also come to the realization I really don't want solid engine and transmission mounts. Even with the rotary NVH become an issue over 8000 RPM. I didn't want to go as soft as factory or even the Mazda competition (40% stiffer than factory) mounts so I found some aftermarket polyurethane ones. RX7 engine mounts are little more than hockey pucks so they're pretty easy to make. However, since I was already ordering the camber links from AWR I figured I'd give their engine mounts a go.

They're a two-piece design, which I figure will make getting the engine out and in a little easier in the future. The only downside is the passenger's side mount (the bigger one) isn't designed to be used with oil pan braces so I had to cut a section out. It's not pretty but I'll deal with it the next time I have the oil pan off.

Other than that I did a quick string alignment since I decided to raise the car up about a 1/4 in. I was starting to notice some bump steer and the rear was nearly at the end of its toe and camber adjustment range. I'll be getting the car professionally aligned after my first event in April at Dominion Raceway. Why after? In what is probably the second largest single purchase on this car I splurged on some Fortune Auto 510 coilovers with all the bells and whistles. Custom springs rates and damper valving, aluminum strut bodies, inverted front struts, Swift springs, etc. I figure these will be the lifetime coilovers from now on. My old Stance GR coilovers have worked well in the nearly 11 years I've had them but it's time to move one. Unfortunately, the custom nature means the FAs won't arrive until after my first event around the end of April. The goal is to get them installed and the car professionally aligned before my event at VIR in May.

infernosg
infernosg Reader
4/6/21 8:40 a.m.

Two week update. Been slowly chipping away at the checklist for my first track day, which is rapidly approaching. Finally got my new SA2020 helmet in last week after a 3 month wait (backordered). Hopefully this one will get more use than my previous helmet. Also decided to pull the trigger on a Garmin Catalyst since they were doing a $100 rebate for the month of March. Really waffled back and forth between it and a more DIY approach with a phone app (e.g. RaceChrono) but ultimately chose the Garmin on the promise they're adding overlays to the video output. Car-wise it's mainly been usual maintenance. New engine oil, transmission and differential oil. Last weekend I replaced the coolant. This year I'm going to try a 75/25 distilled water/anti-freeze ratio. We don't generally see 0F temperatures here in Central VA so I'm thinking I won't have to change it for the Winter months. While I was in there I also replaced the thermostat and gasket. Not sure why I took a picture of this. Maybe to illustrate the proper OEM thermostat and gasket because it was a pain to get the right parts even from "respected" dealers.

I always found it strange the FSM specifies the thermostat be oriented this way. Conventional wisdom is the jiggle pin should be at the highest point. It's also hard to see but the proper OEM gasket has a small cutout on the ID that is supposed to be aligned with th jiggle pin. Oddly, the gasket included with the thermostat did not include this so I had to buy the proper gasket separately. I don't know what, if any, difference this makes. I also took the opportunity to make one change I mentioned previously. Last year I was seeing oil temperatures above 220F at the hotter track days. While not catastrophic I think they should be lower considering the ducting I have on the car. One thought was that because my split ends at the oil cooler I had created a high(er) pressure area in front of the radiator but behind the oil cooler, which was hurting flow. Here's a shot from the back with the radiator removed:

The duct is split at the inlet with about a 33/67% area split going to the oil cooler/radiator. As you can see the split ends at the oil cooler. I'm concern air directed at the radiator "spills over" behind the oil cooler, increasing the exit pressure slightly, which reduces flow. In an attempt to correct this I added another piece that extends the split all the way to the radiator.

You can also see some of the extra bracing I added last year at the front in case the split was deflecting downward at speed. I'll try this setup this year. I have some other ideas for 2022 if oil temperatures aren't improved. Anyway, got everything bolted back in, filled with coolant and burped the system. It's funny how I always seem to take out more coolant than I put back in. I'm confident in my ability to bleed the system but I'll keep an eye on the level in the overflow bottle. I did notice my coolant temperatures being a little higher than they were before. It now stabilized around 183-186F where before is was 179-182F. I think this is probably just variation due to the new thermostat, though.

All that's left is to flush and bleed the brakes. I have new fuel filters but the current ones are only 2 years old. Time permitting, I'll replace them, but I don't think they're critical. I'm also debating wrapping the exhaust again. The last time I tried I did an "okay" job and in the process of removing/reinstalling the exhaust several times it kind of fell apart so I ripped it off. If I decide to go this route it won't be for a while because I have some exhaust changes planned:

That's another Burns Stainless race muffler (4.5" OD, 12" long) and repacking material for my exhaust muffler (6.25" OD, 17" long). The plan is to add the new muffler upstream and inline with the existing one. Because of my long primary system I don't have a lot of space for mufflers so this is pretty much my only option. I'm also going to have the exhaust tip turned down. I don't know if my current muffler needs repacking but I figured it wouldn't hurt to have the materials to do so. Looking at the materials I now know why these mufflers are so light but also have so-so sound suppression. If this doesn't get the noise where I want/need it to be there are some other options. I see some other companies offer SS wool mat I could use in place of the "scrubble" and there's ceramic fiber mat that offers better heat resistance than traditional fiberglass. These are heavier options but probably do better at noise suppression and holding up to the heat of rotary engine exhaust.

The only thing bothering me with the car right now is stuttering/jerking/popping under deceleration. It only does this while decelerating (0 throttle position) from 4000-3000 RPM. Above 4000 RPM and below 3000 RPM it's smooth and I can transition back onto throttle with no issues. For some reason it has issues from 4000-3000 RPM and rolling back onto the throttle is usually rewarded with some amount of hesitation. You can hear in the track video I posted last year. It sounds/feels like the car is running lean but the air-fuel ratios don't agree with this. I've tried just about everything to solve this: add/pull fuel, advance/retard timing and add/reduce timing split (a rotary thing). None of these have had any noticeable effect. I've logged ECU data while decelerating from 9000 RPM all the way down to 2000 RPM. There aren't any weird jumps in timing. Oddly, AFRs are initially rich (no doubt from slamming the throttle shut) but they creep lean (think 16:1) around 5000 RPM. However, during this time I can still roll back on the throttle without issue. By the time it hits 4000 RPM the AFRs have stabilized at my target (be it 14.7:1, 13.5:1, etc.) and the car starts jerking and any throttle input is initially rewarded with hesitation. The only weird thing I see in the logs is the engine loses vacuum in the 4000-3000 RPM range. It's usually -13 to -12 psi but at 4000 RPM it increases to around -11.5 psi. Below 3000 RPM it drops back to -12 psi. My initial thought was not enough ignition advance but that didn't seem to make any noticeable change.

wvumtnbkr
wvumtnbkr PowerDork
4/6/21 9:26 a.m.

When decelerating, why would you have anything except extreme lean condition?

 

In other words, why is there any fuel at all being injected at closed throttle?

 

I would think this could be contributing.

infernosg
infernosg Reader
4/6/21 9:43 a.m.

In reply to wvumtnbkr :

I forgot to mention that. Since this is a rotary and I don't have the factory oil injection pump I'm forced to premix two stroke oil with my fuel. I don't have decel fuel cut (what Haltech calls it) activated because I'm paranoid about not getting enough lubrication to the seals while decelerating. It's something I've considered messing with though. I wish my ECU, an older Platinum Sport 1000, had a few more options like a vehicle speed setting so it only cuts when speed is above a certain threshold (i.e. so it doesn't cut fuel while revving in neutral). The newer Elite models have this. I may give it a shot and see how it works. I just find it interesting the bucking only occurs between 4000 and 3000 RPM. Now that you mention it, it does feel similar to when injection resumes when decelerating to near idle speeds on any other car.

wvumtnbkr
wvumtnbkr PowerDork
4/6/21 10:03 a.m.

Even the omp on stock rotaries are controlled with the throttle position.  

 

Maybe Pete can speak up about that part.

 

I am sure there are people running carbs and premix.  There has to be some knowledge on that.

 

The point you made that you had lower afr in that range made me think that it IS related.

infernosg
infernosg Reader
4/14/21 4:34 p.m.

In reply to wvumtnbkr :

Yeah, I still haven't gotten around to messing with it. The OMP is controlled by throttle position (mechanical or electronic) but I haven't dug into the stock systems enough to understand if they ever completely shut off or not. The issue with AFR is I can have it set at 14.7:1, 13.5:1 or whatever from 5000 RPM to 2000 RPM and it'll only buck from 4000 to 3000 RPM. Everywhere else it's fine despite having the same AFR. Decel fuel cut is probably the way to go but it'll have to wait a bit longer as I'm getting into track season and this isn't something I want to mess with at the track.

Speaking of track I spent some time last night installing the Garmin Catalyst.

The unit itself, the camera and the main power cable can all easily be removed for storage but I spent a little extra time routing the camera cable so it's hidden out of view. While not on track there will just be two little USB ends discreetly sticking out from the headliner and dash. I'm considering moving the unit down since it is kind of large. Tomorrow will be my first test with it and I don't know if it necessarily needs to be right in my sight line since I'll be using the audio queues/aids. It may be better off down where the radio used to be and just angling it upward.

infernosg
infernosg Reader
4/16/21 1:37 p.m.

Spent yesterday afternoon at Dominion Raceway for my first TNia this year. Other than one boneheaded move that earned me a brief black flag there were no issues. The weather was perfect - partly cloudy with ambient temperatures in the mid-60s F. At full tilt on track I don't think my water temperature ever exceeded 195F. Oil temperatures still went above 200F but no where near the 220+ I was seeing late last year. ~30F cooler ambient temperatures are probably the reason for this. I don't think IATs got much above 80F. So yeah, great weather for a track day. Here's the video from what I consider to be the best session:

 

 

I got the play with the Catalyst a bit. With the latest firmware update it now includes overlays with the video export. Here's my best lap of the day (lap 5 from the video above):

 

Overall I'm pleased with the Catalyst. The video quality is okay. It seems about the same as my ancient GoPro Hero2 from the first video. I'm not quite a complete novice so most of the advice is kind of "duh" stuff to me but it's good to have someone (thing?) in your ear constantly ramming home the fact that you blew that last corner. Speaking of, I need to come up with an audio solution. Because the car is so loud the onboard speaker is useless. I ended up using some Bluetooth earbuds, which proved difficult to keep in my ears while putting my helmet on, but worked okay. I didn't have the "advanced race coach" turned on so I was only getting feedback when I did something better. I'm going to try to find some smaller form factor earbuds for VIR in a month.

Not really much planned for the future. Hopefully my FA 510s come in later this month and I'll have them swapped in for VIR in May. I'll probably be back at Dominion in June and am thinking about a Friday at the Track (FATT) at Summit Point in July. I'm told Summit Point is pretty strict about their 103 dB sound limit so I'm hoping I can have my exhaust work done by then.

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