Getting closer to a stable idle with the help of Griff. Car is still throwing a MAF sensor code and I've got a new one on the way. I think this one might be bad since it was near where the camaro got hit. I have an AEM X wideband on the way to start tuning next week.

Got the AEM wideband installed. The AEM X series wideband gauge is pretty cool as it lets you pull the data over the obdii port directly into hp tuners without having to upgrade hptuners to the pro version.


Going to start tuning this weekend. Still need to clean up the chassis harness and get the tunnel back on, then it should be ready for a test drive.

https://cimg7.ibsrv.net/gimg/www.mia...049526940c.jpg
https://cimg8.ibsrv.net/gimg/www.mia...37d45047c7.jpg
https://cimg5.ibsrv.net/gimg/www.mia...e22e36c393.jpg
.

Looking back at my error codes...

0x7E8: P0097 - Intake Air Temperature Sensor 2 Circuit Low

I can't find anything about IAT2. Is this even being used? I am pretty sure IAT1 is on the MAF. Where is IAT2?

I'm not 100% sure where the sensors are that gather the info but I have an ambient and Intake air temp that is logged.

https://cimg8.ibsrv.net/gimg/www.mia...35b94d0aa8.jpg


I am also logging both with no errors thrown.
https://cimg2.ibsrv.net/gimg/www.mia...93e4e1a931.jpg

I will do a bit of digging today to see if I can find out where the sensors are at.

Cool, thanks Griff! I tried searching and I can't figure out where IAT2 gets logged from on the LFX. I replaced the MAF sensor and it didn't fix it, so assuming it is somewhere else.

Found this on a forum in regards to the C7 corvette.

"IAT2 is the true manifold temp. IAT1 is in the MAF. 'Manifold air temp' is a calculated air temp that references IAT1,IAT2 and Ambient air temp."

I wonder if IAT2 is logged from the map sensor on top of the intake manifold. Going to test it this morning.

Posting this up in case anyone needs it. Great reference!

https://cimg8.ibsrv.net/gimg/www.mia...6b1a47be82.jpg

My fuel pressure sensor is going in and out as well. Not throwing a code, but just doesn't read properly sometimes in HPTuners. Pretty sure all of the sensors I'm having issues with (intake cam solenoid, IAT2 and FP) are 5v reference. Guess it's time to bust out the multimeter.

Be aware that GM sometimes uses simulated sensor data - for example, there is no "oil temperature" sensor in the engine. But they offer a six-pack gauge cluster that displays oil temp. That oil temp is based upon a model that the coolant, RPM, and oil pressure are as inputs. I can't imagine what good IAT2 would be use for (well, maybe the battery module). I'll look through my our tune and see if we have it turned off - but I have a feeling that the ambient temp might be taken from the body control module in order to display outside temperatures on the A/C.

Thanks!

Just saw a confirmation that ambient temp indeed has nothing to do with the ecu or how the car runs, it is just simply displayed for the ac. My error codes are all clear now except for the eprom one. Ran the car on jack stands for 15 minutes and gave it a little throttle. Griff has been kind enough to give me advice on where to get started with HP Tuners. So far his recommendation of Goat Rope Garage on Youtube has been very helpful. He has a whole series on tuning Gen 4 GM engines. Car is ready to go for tuning tomorrow.

With Griff's guidance in HP Tuners, I now have a healthy idle. We tried going down the speed density tuning path first and the car just wouldn't play friendly. So MAF tuning it is and the car loved it. With all the intake mods this car has (3.5" MAF pipe, 3.5" full intake, jacfab spacer, 80mm overkill throttle body and jacfab ported intake manifold), it has been interesting. Need to clean up some wiring, remount the ecu with heat shielding and bleed the brakes, and then she should be ready to drive.

Got the car off of the jack stands for the first time in 6 months, and then immediately ran into some issues.

Coolant leak sprung up at the top radiator hose clamp. No biggie, just needed to tighten it down some more.

Had an exhaust leak at both vbands from the down pipes. Not sure what the hell the deal is as I got these pretty spot on. Ended up using some turbo downpipe metal/graphite gaskets for an exhaust with the same 2.5" ID. Cut them to fit within the vbands and now no more leaks.

Used these:
After letting the car idle for 15 min and seeing it hit 220 degrees with the fan on, I realized that the fan I'm using (Spal 30100467) will not cut it. Upgrading to a Spal 30102038. Same diameter, but a couple inches deeper and pulls about 600cfm more air.

https://cimg9.ibsrv.net/gimg/www.mia...9d87e86491.jpg
https://cimg0.ibsrv.net/gimg/www.mia...726cd2b977.jpg

Stock low fan turn on temp is 220… these engines like to run warm. Hi is 224 if I remember. Remember the engine is reverse flow as well.

Holy shit. The oem fans don't even come on until 220?!?! Should 220 be my fan turn on temp, that just seems really high to me. I'm using a derale controller, so it is set independently.

What is considered over heating in these motors temp wise? As in, what temp should an alert come on?

I'll have to double check the tune,. It frightened me the first time we ran ours as well. We ran eBay fans on a godspeed rad and it worked fine, just upgraded to spal for exxxtra a/c condenser flow.

Just as a point of reference since I monitor my temps in my LS3 - it hits 224 sitting at a stoplight on a hot Atlanta day, cruises at 206 after I got my ducting halfway sorted, and I saw a high of 228 in a spirited run on the dragon. The temps are higher than expected but pretty tightly controlled.

The hotter they run, the more efficient they are.

You can imagine my surprise last January as I was driving through Indiana in well below freezing-temps, with my then new-to-me '13 135i, as I watched the oil temp creep past 240. Pulled over and searched. Turns out the thermostat on the factory cooler doesn't even open until that point.

Wow, haha. I definitely would have pulled over too. I guess I'm old school. I always thought if I see a car go over 220 it is because something is wrong.

Syn oil is good up to 280-290.

Anyone installed the V8R carbon fiber intake manifold cover? It looks like I need to cut some of the pieces off of the intake manifold for it to fit, but wanted to confirm exactly how deep and where before I start hacking it up. Also, does it just press fit on or do I need to double side tape it? On a side note, the V8R carbon cover is gorgeous!

https://cimg8.ibsrv.net/gimg/www.mia...d88e5b479d.jpg

I know you must cut down / off that center rib & the tabs that hold the old cover to fit under the NB Miata hood (and some of the hood ribs on the NB for it to fit.). The NA needs an actual hole in the hood I believe. My guess is that’s what you need to remove to make it fit. Unsure how it attaches from there. I’d be worried about double sided tape if you don’t have a hood on your Exocet. Air might get under and lift it off.

Yeah, I'm worried it will fly off with no hood. Just asked ThePass what he did to secure it since his sticks out of the hood.

Looks great on the car and an image of after the cuts for anyone doing this in the future.

https://cimg6.ibsrv.net/gimg/www.mia...2955a36aa3.jpg
https://cimg7.ibsrv.net/gimg/www.mia...7f4c4f0c0a.jpg

Holy hell, so for the last month I have been trying to tune the car to idle without surging. It was acting like it had a vacuum leak, but I smoke tested everything and no leaks anywhere. Went through a couple different tuners trying to figure this out and had a ton of help from Griff on here.

On a whim I decided to replace the valve cover that I had modified (I had removed the pcv valve and replaced it with a 3/8" barb). Bought a new oem valve cover with an oem pcv and swapped it back on. Car idles like a damn sewing machine now using griff's NA tune.

Few things to note...
For the 80mm overkill throttle body the car will need to be tuned correctly, but right off the bat you simply plug in "4224" for the new larger throttle body under the hp tuners throttle area limits. Factory is 3591 I think. The equation to get that number is on the hp tuners forum if you want to dig for it.

Second, don't touch the factory pcv!!! It isn't actually a pcv, but a metal vent on the rear of the passenger valve cover. Modifying it will lead to a cascade of issues the engine does not like and will make it impossible to tune. Don't touch it, ever. Don't even look at it funny.

Lastly, beg and plead with Griff to get his tune if you are running NA. He spent a ridiculous amount of time on it and saved me months of work. I'm sure he would be willing to accept payment for it and in my opinion it is worth it. Be nice and throw some money at him. I'm still waiting for an email back from Will at Overkill and it has been over a month. One day I'll get that tune and look it over, and see if he is doing something better, but for now the Griff tune is the best I have seen.

Trying to get the car on track at Harris Hill within the next 30 days. So diving into MAF and speed density tuning asap to get it running perfectly and then I'm going to beat the hell out of it and see if she has any weak spots.


https://cimg7.ibsrv.net/gimg/www.mia...de4ba3880c.jpg
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What a journey. Can’t wait to see this wrung out on track. I’m so torn on my build now. Thanks

This car began with an nb FMII turbo setup and it was awesome. I always found myself wanting more though in power and reliability. I was right at 250whp, and any more than that with the miata motors is where things get expensive and can be unreliable. The LFX is just such a gem in every way and without any weight penalty, gobs of torque from idle, 325+whp on E85 and a whole engine cost of $1,200, it was a no brainer. I'm a bit ocd and this swap took me about 9 months. That was putting in anywhere from 15 min to a few hours nearly every day. I did A LOT of other upgrades to the car in the process and nearly every bolt has been replaced from the original build (not kidding). Oh, and the power to weight with an LFX in an exocet puts you right around an 800hp corvette. I need to weigh it, but my guess is I'm around 1550 lbs.

I also managed to find a good home for my complete engine, turbo and trans. The sale of the drive train basically cut my build cost in half.

Working on an exocet is such a joy compared to traditional cars. Everything being so open and easy to access makes this swap quite enjoyable and simple to do.

Haha, I feel like part of my job here is to help people make poor financial decisions based around horsepower. :yippee:

https://cimg7.ibsrv.net/gimg/www.mia...6913b293ce.gif

LFX all the way man! I can 100% guarantee that you will not be disappointed and we have most of the issues solved to make it "easy" these days. Plenty of us around to help you out, so there is almost ZERO risk of failure. V8R has several options you can buy now to make things even easier.

Maiden voyage went off without a hitch. Car sounds like a wild animal and it is a whole different beast than the previous turbo miata setup, especially with 3.91 gears.

I'm at the point in MAF tuning that I need to start driving. Went about a mile in total just to be safe and keep it light for the first drive. Filled the gas tank for the first time in 8 months which felt good. Will be doing some more light driving tomorrow and try to get the MAF tune closer, it was pretty far off today. I'll try to get some in car video tomorrow. The exhaust sounds amazing, reminds me a lot of an LS oddly.

Have a few "permanent" DTC's that are being stubborn and not going away. Started digging around and found the process to clear them.

http://www.obdii.com/drivecycle.html

To perform an OBDII Driving cycle do the following:

1. Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.
2. Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.
3. Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
4. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
5. Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
6. Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.
7. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.
8. Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.

Ehh.. that OBDII drive cycle is more based on setting engine readiness for emissions. Permanent DTC's more or less need to be disabled via HP Tuners. Some of them (like the earlier eeprom checksum) cannot be reset, but you can at least prevent them from tripping the check engine light (MIL).

Yeah, this gets interesting. It appears it is the government getting involved in preventing people from clearing certain emissions related codes.

https://www.autoserviceworld.com/car...ermanent-dtcs/

From what I read, the permanent dtc codes are emissions related, hence why they can't be deleted or reset with hp tuners. So to clear them, the issue has to be fixed and then the universal trip drive pattern must be done. Edit: it mentions a specific cycle to clear some of the codes as well. I don't see this in the service manual for the Camaro though.

Yeah, it's the fun of more sophisticated ECU's and tuning software and the kerfuffle with EPA going after motorsports for emission compliance stuff a few years back - it's not a technical limitation of the tuning software, but a legal one. Ultimately it's a PITA. IIRC, there is a difference between a DTC that's set (that triggers a MIL) and stored (permanent).

You can turn off the MIL by being clearing with a scanner, but it remains until drive cycles reset it. Case in point - I split the air filter boot on my LS3, which led the MAF to read low, which caused the engine to lean out. I disconnected the MAF - that triggered a code - but the LS3 also has a MAP sensor to failover. I could clear the MAF code with Torque - but until I fixed the boot and replugged the MAF and drove it for a little bit - only took a day or so to clear that code.

Got some good driving in this weekend, and now it's time to start sorting out the small issues that arose. I had three leaks pop up. One from the passenger side lower drain plug on the supermiata radiator. I think it just wasn't tightened all the way and under pressure had a small drip. Next was a light leak from the banjo bolt on the clutch fitting. Again, I am pretty sure it just wasn't tightened all the way. Cranked down on it a bit and we'll see what happens. Lastly, and the one that concerned me the most, a light leak from the rear of the oil pan where it meets the trans. I slightly re-torqued the rear oil pan bolts and then the lower trans mount bolts. I'll keep an eye on it and see what happens.

And for the grand finale, my exhaust vbands are leaking too much to continue ignoring. I'm pretty sure it is effecting my wideband on the driver side and messing with my tuning process. So the exhaust is now off and I'm going to cut the vband fittings off the rear half, use the clamps to connect them to the front half, remount the rear and tack in whatever pie cuts are needed to make this damn thing fit perfectly. Trying to get all this done during the week so I can be back on the road tuning next weekend. I need to hurry the hell up and get this thing track ready so I can meet up with Griff at Harris Hill before winter takes over.

https://cimg4.ibsrv.net/gimg/www.mia...51df4a9273.jpg
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The person that designs a simple EFFECTIVE alternative to V-bands is going to make a fortune! Hard to tell from the pic if that is motor or gear oil. Which one did it smell like? MVs are notorious for input and output seal leaking.

I couldn't tell if it was motor or gear oil. I'll smell it next time I'm under the car. If the input or output seal is leaking will it effect anything other than just being an annoying slow leak?

Edit: I'm using royal purple gear oil and it definitely wasn't that color. So motor oil. I tightened up the rear oil pan bolts, so we'll see if that fixes it.

I have a slow leak on my rear output shaft and I just clean it up and verify oil level each time I'm under the car.

Used permatex high-temp copper rtv gasket on the vbands and they are perfectly sealed now.

Finally got the car idling correctly on the maf tune setup in hp tuners. Warmed it up and everything was perfect, then the fan kicks on and the car starts surging and idling like shit. Weird. Turn it off, start it up and it does it again. Fan comes on, idle goes south. Fan turns off, idle goes back to perfect.

Talking with Griff and there is something weird the ecu is doing to compensate for the amperage draw when the fan is on. It draws about 21 amps continuous. Trying to figure this out and came across a thread on the hptuners forums that is VERY interesting. Going to test some of these settings out and report back. I'm only drawing 35 amps total continuous with the fan on, so I'm definitely not maxing anything out.

https://forum.hptuners.com/showthrea...der-system-tab

That thread is just a dump of the GM diagnostics info for the charging system. It does not have any new or additional information on making it work without a BCM.

That said - I'd be looking at your wiring if the fans are dragging down your voltage.

My fan is connected to standalone derale controller. I get the initial idle surge to 14.7v, but it goes to 13.3 after that regardless of the needs. Tried unplugging the alternator and that didn't seem to do much either. In hptuners there are settings to compensate for oem fan kick on. Just seems like they won't do much in this case.

Alternator will default to 13.6v when disconnected. Anything less than that either indicates the voltage internal voltage regulator is messed up, or you have insufficient gauge from the alternator stud back to your fusebox when under load.

Trust me - nothing in those hp tuner settings will do jack squat. Been down that road.

I can confirm that now. None of the settings do shit unfortunately.

I just ran the power wire for the derale fan controller directly to the battery positive post. Will test it in the morning and report back. Fingers crossed.

Ran the derale controller directly off the battery and it still did it. Bypassed the derale and used my power probe to run the fan directly off the battery still did it. Hooked up my og smaller fan that only draws 7 amps and turned it on, all good.

I am fairly certain the big fan just draws so much power at start up (and drops my voltage into the low 12's) that the ecu sees that and freaks out. That bigger fan is so awesome and powerful, but it just isn't going to work.

Or run a capacitor. The 1.5 or 2 ferad ones like they use in mobile audio setups should do the trick. We can bust out a calculator to verify before you buy one.

I think you will want the bigger fan while sitting still on the paddock after a few hot laps.

Sweet!
I'm just happy to be able to tune it finally with all the headaches. Let me know how big you think the capacitor will need to be.

Won't work.

I would 100% trust Goof's input over mine and I'm curious what solution he suggests. Possibly a trigger start over a typical inrush?

http://www.wolstentech.com/products/timedelayrelay/timedelayrelay.php

Starting to look into the possibility of building one of these things (Exocet) for time attack. Instead of dumping thousands more into supercharging, moving to an easy to work on and ultra light weight tube frame chassis that I can run whatever wheels and tires I want sounds amazing....

Any more info on the alternator issue? If it was on the passenger side like its supposed to be was the frame just too close to the stud? My stud is close to the subframe, not the miata body frame rail...

For me, the frame and subframe were in the way. Everything I have read and experienced is that power steering is not needed on an exocet. The ideal place for the oem alternator so you don't have to cut the frame or subframe is just to flip the mount and put it on the passenger side power steering location. Someone on here custom fabricated a mount for an aftermarket alternator to put in the oem location. Seems easier just to move the oem one.

Update time... finally got my Overkill tune and was very impressed. Did a drive and sent him a log and just got revision two back. For anyone looking to do an overkill tune send him your base file as soon as possible. It will take at least a couple months for him to get back in my experience. I even offered a bribe to cut in line and it was a no go.

As is the theme of this build I immediately had a couple more issues.

The exhaust is the loudest exhaust I have ever heard excluding straight pipes. It was way too ridiculous. So I pulled it off for the 50th time and cut the muffler open. Added a few baffles, some screens to keep the packing in and shoved some cut-up high temp (1800 degree) ceramic exhaust packing in it. Welded it all back up and just got it back on the car. Fingers crossed it is toned down a bit now.

I was also running into some issues with wild MAF readings. My MAF sensor is about 3" from the back of my intake cone and ideally it should be twice the diameter of the tube away from the intake cone to allow the air to straighten out. I ordered a MAF straightener which is essentially some honeycomb stainless about 1/2" wide and the diameter of the intake. Read some very positive things on these and hopefully it does what it is supposed to. I epoxied it into place just for security and it came out great.

https://performancemrp.com/i-3049756...tegory:1389190

Car is back together and the weather looks nice tomorrow for another tune and log. Will update shortly.

Got a 10 min drive in on the new tune and holy shit... Haven't really had the chance to get on it yet, so today was the first time. I've been in some fast cars, but nothing like this. And the amount of torque from idle is just insane. Not even on the E85 tune yet, so we'll see how that goes. Managed to spin the RC1's in third gear and they were warmed up. I'm sure the 3.91 gears helped, but god they make roll-ons so much fun.

Need a proper alignment asap and will keep working on the tune. Other than that, car seems to be perfectly setup. The Xidas on the softest setting made the ride quality very good and even with a shit alignment the handling is out of this world. I love the swaybar setup I ended up with thanks to Emilio's suggestion (stock rear sway and 54102 Racing Beat front). And the new shifter from V8R is pretty amazing, highly recommended.

So fed up with vbands. I've welded the vbands on my echaust three times now to get them as perfect as can be and they still leak. This is using the very nice inner flange vbands from stainless bros (ticon). I've tried gaskets, high temp copper seal, rewelding... nothing works and vbands are garbage.

Came across this video, anyone used or seen these in person?


Just ordered two sets in 2.5" stainless, we'll see how it goes.
https://www.ebay.com/itm/SALE-2-1-2-...S/264178895070

In all the Caterpillar construction equipment that I work with, its all marman flanges for exhaust. I'd be surprised if they dont work for you

I can't figure out why companies still make vbands, they are absolute trash and don't seal 100%. These seem like a much better option that is proven to work.

Build is pretty much done at this point. I'll redo the exhaust again and ditch the vbands and update once that is done. Once I get the tune finished there isn't really anything else to do but drive it.

Picture dump of the car as it currently sits with the chopped hood.

https://cimg7.ibsrv.net/gimg/www.mia...580bca65bc.jpg
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Switched out the vbands to the GBE marmon flanges. I like them a lot and no leaks. Would definitely recommend these.

https://cimg0.ibsrv.net/gimg/www.mia...d5b10a5fcd.jpg
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The spintech 6000 street muffler is just too loud. Even after cutting it open and adding baffles, the car is undrivable without hearing protection.

For exhaust version 37, I'm switching the spintech muffler out for a pair of Flowmaster HP-2's (12512304). I like the design of these internally and believe they should quiet it down a bit. They will also fit in the small area below the driveshaft in the tunnel.

I've done more research on muffler design than I care to admit. And after reading multiple thesis papers and everything else I could find, I believe for the size restrictions I have the flowmaster HP-2 is the best solution.

https://cimg1.ibsrv.net/gimg/www.mia...ef8a632c1a.jpg

Flowmaster HP2's weren't even close to fitting in the tunnel. Called spintech and Ron is making me a custom muffler. I have an extra inch to spare in width and length over their standard 6000 pro street muffler, so he will be building one to that size with their sound deadening material on the walls as well. Fingers crossed the exhaust is toned down enough to not need hearing protection.

I have concerns about breaking the oem miata diff housing, even with the kmiata bolt-on brace. I have been looking for a good deal on an FC NA RX7 housing for a while and just came across a 1991 S5 diff for $250 shipped in Texas. There was a comment on Greg Peters' video that was insightful on there being two different FC RX7 NA diffs. One being stronger and it is based on the year of manufacture. I ended up getting a 1991 diff based on the info below. Interesting because I have never seen that mentioned anywhere before.

cmoore74

/UCClPhbuoAOL6nvLg8HirQqw

3 months ago (edited)

"Hey Greg... the diff carrier you’re using is from a S4 (86-88) Rx7. The S5 (89-91) carriers are 2lbs heavier. The S5 has thicker webbing across the "beam" .475 vs .320 for the S4. The S5 also has been triangulated in the beam area as well as having the lower web of the beam merge with the output shaft saddle. All in all the S5 is a beefier unit."

Went ahead and ordered new axle seals and in case anyone else has trouble finding the part number, here it is. ***Still not 100% sure this is correct, but I'll confirm when they arrive.
https://www.mazdatrix.com/product/di...86-92-n-t-all/
Mazda Part # F003-27-238C

Got the 1991 FC RX7 diff and have it all disassembled except for the bushings. A friend has a press at his shop so I'm just going to do them there tomorrow.
OEM diff vent was clogged and stuck, so ordered a new one from ebay. Part #0730-26-060
Got some new energy diff bushings and OS Giken lube from Supermiata on the way.

I was looking at Greg's video again and they are definitely different. The S4 FC RX7 diff is pictured first and the S5 second. You can read the quote in my post above for the exact differences.
https://cimg1.ibsrv.net/gimg/www.mia...321ffbad99.jpg
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