i got a free 4x6' sheet of .090 aluminum from a friend of mine, so i decided to make a front splitter. here are some pics.

i'm about 1/2 done. i need to make all the mounting for it now.

question: are the rotors dumb? i'm not a rotary fan boy, but this rotor was a good size to make some holes.
i had enough extra material to make another, so i actually have two of these. one has the rotor holes cut out for my VMIC fans, one is all solid with no holes.

it had been so long since i'd used a plasma cutter that i almost forgot how awesome they are.

my next step is to drill holes to mount the rear of this to the front sway bar bracket bolts, then attach some thick aluminum L brackets to the splitter so i can attach the middle area up to the frame rails and get some real support.
i'm not sure how to attach the front of the splitter. maybe several bolts up through the front lip? also i'm not sure if turn buckles will be necessary (sticking up through the radiator opening).


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more progress on the front splitter:

I made some nice L brackets to support the splitter front-to-back, and will use the same rear mounting point (the front sway bar front bolt)

i'm not entirely sure how to support the splitter left-to-right without doing a lot of fancy bending (which isn't feasible) or welding, or both. anyone have any ideas?


also, a little booboo: the two brackets aren't perfectly parallel, and they aren't perpendicular to the rear of the splitter. not much of a problem, but it does bug me slightly :)

anyway, here are the pics. it is starting to look pretty good.

I notched the front of the L brackets to fit nicely inside the OEM front lip.
Attachment 751878

I copied the driver side bracket cut for the passenger side to keep them similar, and so I didn't have to do all the trial and error cuts again.
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brackets attached
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more bolts added for rigidity
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Looks good, afgmoto1978 did a lot of splitter work a while back. Might have some ideas for you in his build thread.

https://www.rx7club.com/build-thread.../#post11342448

more pics:

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my zada-tech gauges came in finally after a shipping mix-up. they are really cool:

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i'm going to install them into my DIN pocket, in this nifty little blank piece I made from some spare plastic:
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oil temp sensor:
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I got some good (not bent) sway bar mounts from that goodfella richy rich, cleaned them up, and painted them:
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I am 99% finished with the splitter. I went 140mph and it didn't bend or fly off.

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Jacob - Pay close attention to that flat stock bar mount in the wheel well. The OEM wheel/tire combo will be fine, but larger diameter/wider tires may end up rubbing that that spot. I don't think it would cause much damage ... just providing some cautionary advice.

thanks for the word of caution.

I did take that into account, leaving a little over 1" of clearance for this wheel and tire setup at its closest (nearly full lock), assuming any future wheel/tire upgrade in the future should be ~1% of stock diameter.

a 265/35/18 is +1.6% in diameter, which is +0.4" --- this would be worst case scenario
a 285/30/18 is -0.8% in diameter, which is -0.2"

regardless, thanks for looking out. if I end up with tires that are +2% or larger I will move the bracket forward to get some more clearance.

Nice work man!

Question on the splitter: Does it sit flat/level? The issue i've always had thinking about this is that the bottom of the lip isn't flat (it's lower at the outer/back edges than at the center, so there was always the question of what to do with the gap. Did you trim the lip?

P

hey peter man, turn on channel 9, breast exams!

about the splitter being flat/level, the lip is indeed not flat across the front left-to-right, as the sides near the fenders are thicker. the .090 aluminum I used is thin enough to barely flex and meet the slight contour of the front lip, so it has a very slight bow effect... now, for all the armchair aerodynamics engineers out there, i'm aware this is not totally ideal.
i used every mounting point for the front lip as the front attachment point for the front of the splitter. when you think of that concept initially you may think it's not ideal, but there are 14 bolts, which is a lot. the urethane bumper isn't the most solid structure on the car, but 14 of these bolts in a "bow" pattern supporting the splitter makes it pretty damn rigid.
if i were using thicker 1/8" aluminum (or something equally rigid) it would have left a ~1/4" gap in the center section between the splitter and the lip, and i would have to use some urethane or vinyl to seal that gap top-to-bottom, if that makes sense. (that is what most people do). my material was simply thin enough to mend slightly to the shape without smashing the front lip.

about the splitter being level, it's not perfect, but it's close (front-to-back) using the sway bar bolts as the rear splitter mounting point. to change the angle of attack on this splitter i would have to drill additional main "mid" mount holes and simply adjust the 14 "front" bolts to lower the front down -- this would create a slight gap that i mentioned above, which i would have to seal up as well. i will take some measurements of it with the car on the ground later, to make sure it's not actually creating lift instead, but when only looking at it, it looks pretty close to level front-to-back, so overall it may actually produce a little downforce.

my main objective was to collect a little more air for the radiator/IC/oilcoolers, and a little more downforce as my secondary objective. hopefully this does a little of both, but i don't have anything quantitative to actually determine its effectiveness.

maybe at least it will cut the ankles of a few of the random-question-askers at the gas station:
"hey man, is that thing twin turbo??? my uncle had one of these in 1764!"
*steps closer to look at the mis-matched hood*
"my ankles!!! they're bleeding! oh my god!!!!!"

another update i forgot to post prior to the front splitter:

i installed new OEM oil cooler ducts. the RX8 cooler on the passenger side is 2 rows taller, so the duct didn't quite fit, but i modified it a little and got it to work as well as it can.

pretty new ducts
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driver side bottom
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driver side top
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taller RX8 cooler on passenger side
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passenger side bottom
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passenger side top (i re-did this one after the pic to raise it slightly, but it looks almost the same)
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regardless, thanks for looking out. if I end up with tires that are +2% or larger I will move the bracket forward to get some more clearance.


Yeah, I think the issue is worse when you have wide wheels or low offset so more outer barrel is sticking out past the steering axis.

https://www.rx7club.com/attachments/...tire-close-jpg

^valid point.

I just did the quick maths using a right triangle calculator and my 18x11 +45 are like a 32" tall tire if you measure diagonally through the steering axis to an outer tread block.

Stock with 24.9" tall tire is like 28.6" tall tire through steering axis to an outer tread block.

So 1.7" closer on my set-up by my calculations.

I have a nice rub spot developing in that area where the bracket is. Rocking 18x10.5 +43 with 285/30. The fender liner has some flex so it will move, but that bracket probably doesn't.

I like the execution though. I am using the Shine Auto undertray, which is a three piece CF unit. It has the similar shape you have with yours. I wanted to "tie up" the portion of the trays near the oil coolers just the way you have them, but I feared the tire rub. I may revisit and use brackets more inward. Thanks for the idea.

that is good info. i measured my ~1" gap with the tire at its closest point to the support bracket. i wouldn't be able to run an 11" wheel... are you running like 305s on that?

can you even steer yours without hitting the washer bottle? the radius curve on mine has about the same clearance for the bracket as the washer bottle does.

18x11 +45 and 295/30-18.

No, it doesn't rub anything on stock rolled fenders except on a big bump that top outside part of the fender liner between 11 O-clock to 1 O-clock that just hangs now that the fender lip that it used to bolt to is rolled under.

the zada tech gauges are installed into my DIN pocket.

the sensors aren't hooked up yet. i will do that in the next few days. i need to find a way to cleanly get them through the firewall.

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Nice Stuff Jacob!

Those gauges are tiny! I guess they are perfect for your stealth install.

I think a row of these would go perfect along the bottom of the gauge cluster if someone wanted to actually monitor and drive at the same time.

yeah I wanted to install them into the warning light area (the one closer to the center of the car) but the only light on that side I was willing to sacrifice was the airbag light, so I wouldn't have been able to fit both gauges.

I also like being able to close the little door on the DIN pocket. the gauges are bright, so it will be nice to close them of when I don't need to watch them.

They look nice but are a bit tiny, are they easy to read? Especially you have to look down to it.

yes they are easy to read. the picture/exposure in the dark from the driver view made it look worse than it is. the OLED-ness makes the clarity and brightness very good. they are indeed quite small though. I could move the DIN pocket up into the top "slot" if the visibility became a problem, but I don't think it will.

I also have boost readout on my PFC commander, but it's in Kg/cm2, which is annoying, and the refresh rate isn't super fast. the refresh rate of the zada-tech gauges is super fast. the boost is consistent on this car, so my main concern is being able to watch oil temps.

I got back to work sunday with johnny's/charles' plasma cutter.

I've needed to block off the open space between the intake/IC/battery, so I made some cardboard templates and cut them out of my spare .090 aluminum. I haven't mounted the plates yet (they are just laying in there) but I will use the 4 front bumper mounting bolt holes with some standoffs and some countersunk allens. hopefully it will end up pretty nice. the plates aren't perfect, but they turned out decent.

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Looks awesome! Will you try to block off the open section near the passenger headlight of the cxracing intake and cut out the bottom to match the vmount opening? Sorry if I missed a beat about it.

Also, did you refurb the oil cooler ducts with new rivets and covers? If so, what material did you use and where did you get it?

thanks guy :)

1. about the intake opening, it is actually open on the bottom (inside the "V") - there are two openings. it appears that they left the top (near the headlight) open for cost savings. the M2 intake, which this was copied from, has that opening sealed. I guess a multi-angle seal in that top intake opening would have cost too much? haha.

2. they are new OEM oil cooler ducts. I got the part numbers from jimellismazda, which is a great resource for finding OE #s btw, and googled them and found an online mazda parts retailer for about $80 each, IIRC. They were cheaper than I thought, and at $160 total, I figured that was worth the materials + an entire weekend i'd have to spend to make my own ducts that wouldn't do much better, right?

With all that metal work experience you should make your own ducts. Make me a set also. I don't have any for my SakeBomb kit. :nod:

FYI, if you ever need any more oil cooler ducts for a future project Ray Crowe sells the ducts for around $50 apiece. I just bought a left and right set from him recently.

really? damn, i'll have to keep that in mind next time.

i mounted my vmic ducts. i've discovered that i may have an addiction to online shopping on mcmaster.com for 18-8 stainless hardware (and aluminum standoffs and spacers).

i also went out and did some repeated 3rd and 4th gear full boost redline pulls (i'm talking some serious heat generation) over the course of about 5 miles in the 70*F weather on the way home from work, and the IATs didn't get over 42*C (107*F)

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That metal would really look good powder coated. You might be surprised how nice. Really adds an OEM look to home made metal work. It's a nice finishing touch.

Nice fabrication work, looks great :icon_tup:.

good stuff Jacob.

And good idea, i will prob do this. Need to make an intake first.

its been awhile!

let me please share my frustrations with the last hurdle on this project:

back story:
I have a MANA system from a 1994 (with the more conventional-looking expansion valve, not the denso block style).
^this all came from the 94 salvage title donor car that had functioning AC, but the high pressure side of the system only ran about 120-130psi, low side about 40psi.
^so, I figured the compressor was weak.

fast forward to now:
the last hurdle is the A/C. I have reinstalled everything after cleaning the evaporator box, all lines, re-welded the high pressure line between the condenser and dryer, and installed a reman compressor from 4seasons.

here's the problem: (pic while compressor is running) Attachment 751505


it seems like the compressor isn't compressing. I can't get the high side pressure to go any higher than the low side. there's also zero pressure drop on the low side when I kick the compressor on and off and back on...
I pulled a vacuum on the system for about 30 minutes, purged the line and charged a few ounces into the low side, started the car and got the compressor to activate, and the pressure on the high side simply doesn't go up higher than the low side.
I drained the system and blew through all the lines to make sure there were no strange restrictions, and all pipes are clear of debris and restriction. (and a restriction would cause the pressure to go up on one end anyway) I then re-charged and tested again, just to make sure. same result.

it's like I have a LACK of restriction, so the compressor has no resistance at the expansion valve and the gas is freely flowing through both sides easily.

things of note:
1. I can hear gas flowing through the expansion valve when the compressor is activated, but it sounds like a hissing sound, similar to what it sounds like when the system is low on refrigerant.
2. I purchased and installed the reman compressor only because I had the exact same symptom with my previous compressor.
3. I had the expansion valve out to inspect it (I blew through it with my mouth to check how much restriction there was vs a valve I had sitting around for a different car) and the restriction seems to be about the same between the two. I am currently waiting for a new expansion valve to arrive in the mail, but I am skeptical that the valve is the issue. has anyone ever seen an expansion valve fail in a way that would create "not enough restriction" ? I've only heard of them getting clogged and making the pressure spike up on the high side.

i'm basically out of things to check, i'm doubtful the expansion valve is the entire issue, and i'm very frustrated!

yesterday I had an epiphany, so last night I did some research on some hotrod forums (mostly of guys building custom AC systems) and discovered that my own incompetence is the reason the AC isn't working (isn't that usually the case with custom stuff like this?) :)
i mounted it this way because it was easier (bigger pipe on the condenser facing the correct way), so if it doesn't matter, then "why not" ? :)
I actually built a custom AC system for a previous FD of mine (red track-ish car) and I guess I just got lucky on that one because I was not aware of this concept.

i have the condenser mounted upside down. the compressor discharge hose (the condenser inlet) on the BOTTOM, and the liquid outlet on the TOP.

---inside the condenser the refrigerant turns back to liquid (to then be sent on to the dryer and then expansion valve and evap to do the magic).

well, if the liquid outlet of the condenser isn't at the bottom, gravity holds the liquid at the bottom and it can't get out of the condenser, so the only thing that can get out is the gas. the gas just bubbles up through the liquid and exits out of the top, then through the rest of the system.

the gas then easily flows through the dryer, expansion valve, and evaporator, and no compressing gets done on the high side because there's no restriction at the expansion valve.

---this makes perfect sense now because i could hear gas flowing through the expansion valve with the compressor running (like a constant hissing sound).

Attachment 751488


i now have the condenser flipped into the correct orientation, so a friend welded the outlet again for the correct orientation/mounting. this required also making a 180* for the inlet which i will have finished tonight.

this has been quite frustrating, but i now have a fresh compressor and expansion valve, so this thing is gonna be blowing cold!!!! and I've learned more than i thought i would.

also, i picked up some R152a air duster like I've used in my previous cars (after wasting several cans on r134) so i will be using that.

another AC update:

last night I flipped the condenser to put the liquid outlet on the bottom, and had the larger inlet re-welded to accept the compressor discharge.

I did all this work, reinstalled my reman compressor, vacuumed the system, charged the system, and *same issue*.

it seems that when I release the refrigerant into the vacuumed system it takes 4-5oz and just stops charging. I jumpered the pressure switch to activate the compressor, and it draws maybe one more ounce then won't take any more.

at that point I could see some flow inside the sight glass: a very fast flowing fine-bubbly (maybe cloudy?) like the system is low on refrigerant, and I could heard the expansion valve faintly hissing with flow. gas was apparently moving around in the system. I felt the temperature of each of the pipes:
the compressor discharge and condenser inlet were both too hot to touch.
the condenser liquid outlet to dryer line was cooler, close to room temperature (80*F).
the liquid line from dryer to expansion valve was about room temperature
the suction pipe going from the evap to the compressor was cool but not cold.

it seemed to me at this point that the compressor was simply not sucking and pressing hard enough, but the compressor itself was hot. not quite too hot to touch, but close.

I drained the system, reinstalled my original compressor (that last summer showed low side of ~40psi and high side ~150psi, a little low) and the exact same conditions happened.

i'm now complete out of ideas. what else is there?

I dont have any ideas but i think i'm gonna hold off on my install install until you have better luck.

you are welcomed to try the compressor, dryer and condenser i have.

I think the issue lies with your expansion valve. It sounds like you have a TXV expansion valve. If so, are the bulbs mounted to the compressor line properly? One should be taped to the outside with a thick tar like covering to isolate it from the ambient temperature, and the other should be mounted with a fitting. Also, be sure they are not kinked? These contain mercury and regulate the opening and closing of the valve. If they are not mounted properly they could prevent the system from flowing correctly.

thanks guy! i actually just got it figured out. see post below. (it was the ambient temp and condenser temp)

i finally got it figured out.

it turns out that the issue (on top of the initial flipped condenser inlet/out) was that my garage and condenser were way too hot.

i picked up some r134a cans on my way home from work, vacuumed the system down, and recharged with a few ounces of r134 to get the system pressurized and the compressor to kick on.

it still wasnt compressing, so i pulled the car out of the garage where there was a breeze (still 85*F ambient temp outside today), and i sprayed ice water onto the condenser out of a bottle while i had the compressor running.

WALLAH.

it started accepting more refrigerant. the high side pressure was rising and dropping quite a bit depending on the temperature of the condenser. i also raised the RPM to 1500 as the FSM states, and the pressures actually started looking pretty good. i got them to about 30psi on the low side and about 200 on the high side.

i ended at about 18oz of r134 and one 3oz can of r134a/PAG oil charge (100wt) and the thermostat is now cycling the compressor on and off. this was music to my earz. :)

the vent temp is about 50*F sitting at idle in 85*F ambient temp. 50*F at idle in 85*F ambient is good. this is what my previous FDs have been.

i haven't yet cruised on the highway, but i will be in a couple hours. i'll report back. i am assuming it will stay at about 35*F with the RPMs up and lots of airflow through the condenser.

today is a good day!

How did the road test go? Anxious to hear.

road test was great!!!!

the thermostat cycles the AC off/on at about 45-50*F vent temp.

i cant pull a vacuum harder than about 24", and i accidentally shot a tiny spurt of air (didn't purge the line on the first can).
so i'll re-do it and get it even colder.

:)

Awesome fix......really good job diagnosing the problem, the rest of us following your effort "didn't have a clue".

update:
I swapped the autozone loan-a-tool gauges and vacuum pump for better units at a different store, and recharged the system with r134a. this time I got a hard vacuum of at least 29inHg, and I let it stay in vacuum for about an hour. I recharged it and it got very cold.

Attachment 751475




here is the vent temp after the car greenhoused for several hours in 85*F+ heat last weekend:
Attachment 751476

and here is the temp after about 10 minutes of AC running:
https://i.imgur.com/N6lasWth.png



fast forward one week to today, and the AC is still ~38-40*F at the vents. I am quite pleased with this MANA ac system with a new expansion valve, hard vacuum pull/charge, and R134a. the AC is colder than most new cars I've been in (and I drive a lot of new vehicles for my job)

nice, i hope i get similar results tomorrow.

track day prep

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I need to see oil temps! I got this cheapo Chinese oil temp gauge to fit into the DIN pocket. it closes and it's out of my face. I love it. (1/8npt sensor is in the oil pay drain bolt)
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random: I just discovered the 1994 lit keyhole actually works on this car. I love it.
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new non-bose rear carpet from EHS. also, I love it.
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used rear storage bins and rear divider from ebay seller.
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track day !!!!
https://i.imgur.com/nmMHU1Vh.png



almost ready to go
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made it
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at the track
this is the only white non-generic t-shirt I could find at Walmart...
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the tires were basically like plastic out on the track. they were terrible.

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VOLT racing team was here testing their insane McLaren...

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here's a video of me basically forgetting where I was on the track. enjoy :)





the CARTMILL VMIC setup performed very well on the track.
AIR TEMP didn't get above 60*C (~140*F), which is about 20*F cooler than my previous two cars in similar conditions (~90*F outside and high humidity).
COOLANT TEMP was also rock solid, peaking around 95-96*C (203-205*F),
OIL TEMP was also very good, peaking around 200-205*F



overall thought:
an FD on sequential stock twins with all necessary supporting mods and tuning is a BLAST on the track. this was my first time tracking a sequential car. during the tuning process we got the transition to be quite mild (not a big black of torque like some of them can be) and it was a non-issue on the track. i'm sure there is a metric assload of heat getting built up inside that exhaust manifold at full chooch, but they handled it and did a great job. the combination of the VMIC, stock boost level (~10.5psi), powerFC and tuning, and stock shocks w/ tein h-techs made the car a blast to drive on the track. on the track I definitely noticed the suspension could be harder, but I stand behind my statement that these tein h-tech springs on stock shocks (I think mine are non-r1) with new rubber mounts is a perfect combo of street and light tracking.
the tires were terrible. these are the worst tires I've tracked on, and the soft(ish) suspension mixed with the large sidewalls on the tires made it feel a little looser than I was used to, but overall it did very well.
also, keep in mind I daily drive this car.
I recommend this setup to others.

back from the track!


fuel pump level gauge stopped working while at the track, and I tracked it down to this little guy
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also, I installed a auto-dimming UGDO rear view mirror (gentex, got it on amazon)
Attachment 751191

then I went on a work trip, into the desert in Palm Springs CA

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then I started a very over-done workbench adventure:
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