She Followed Me Home, Honest
See, that's what I was wondering...if the valves are C>O>C why go through all this monkey motion to activate them? Why not just use a direct electric method or even better, cables (maybe off the throttle body, maybe a whole separate cable from the pedal), which make it purely mechanical?
Even the one actuator that moves right now takes more than 3-5psi, I'd bet.
Even the one actuator that moves right now takes more than 3-5psi, I'd bet.
The actuators are fairly large and I'd bet they have more than one square inch of surface area. A caliper or scale, estimation of diaphragm diameter, and some pie are squared could give a decent idea of the actual force of the actuator.
Joined: Mar 2001
Posts: 31,816
Likes: 3,219
From: https://www2.mazda.com/en/100th/
See, that's what I was wondering...if the valves are C>O>C why go through all this monkey motion to activate them? Why not just use a direct electric method or even better, cables (maybe off the throttle body, maybe a whole separate cable from the pedal), which make it purely mechanical?
Even the one actuator that moves right now takes more than 3-5psi, I'd bet.
Even the one actuator that moves right now takes more than 3-5psi, I'd bet.
i was going to try and make a funny about the Rx8 intake, as its got an electric motor and gear train, and the joke was something like Mazda not being able to get blinker fluid to work, but they have done muffler bearings, and now you can periodically replace the gear in your intake manifold.... failure rate is too low though. if you want the really weird one, BMW's have shocks in the seats, they do go bad.
Yeah, I get that...but-
I just skimmed the RR tutorial on converting from stock air pump to electric air pump actuation and he uses an RPM sensing trigger (which can be set to different trigger points apparently), so it only uses one data point (RPM) to control the ports.
This is hardly a sophisticated control program and I wonder if it couldn't be approximated with an adjustable contact switch mounted on the throttle body which ran a solenoid to open the ports.
This assumes a rough correlation between throttle angle and RPM.
Even better IMO, would be a completely mechanical (i.e., cable) actuation, no electrical, air pressure...no nuttin. This could be set up progressively (ports begin to open at say, 40% throttle and are fully open by 80%...obviously just a guess) or all at once (ports fully open at 50% throttle).
My thinking here (based on myriad hazy assumptions) is that with the stock system the ECU is using multiple inputs to decide when to open the ports. The (seemingly) acceptable replacement setup from RR uses only RPM as a factor and doesn't appear to suffer from the simplicity.
Then there are those who just wire them open and claim not to feel much difference.
Not sure I believe the latter group but I could actually just try it on my running motor and see for myself.
In fact, now that I think about it, I could build the cable system on my running engine and decide then...
Oh, oh.
I just skimmed the RR tutorial on converting from stock air pump to electric air pump actuation and he uses an RPM sensing trigger (which can be set to different trigger points apparently), so it only uses one data point (RPM) to control the ports.
This is hardly a sophisticated control program and I wonder if it couldn't be approximated with an adjustable contact switch mounted on the throttle body which ran a solenoid to open the ports.
This assumes a rough correlation between throttle angle and RPM.
Even better IMO, would be a completely mechanical (i.e., cable) actuation, no electrical, air pressure...no nuttin. This could be set up progressively (ports begin to open at say, 40% throttle and are fully open by 80%...obviously just a guess) or all at once (ports fully open at 50% throttle).
My thinking here (based on myriad hazy assumptions) is that with the stock system the ECU is using multiple inputs to decide when to open the ports. The (seemingly) acceptable replacement setup from RR uses only RPM as a factor and doesn't appear to suffer from the simplicity.
Then there are those who just wire them open and claim not to feel much difference.
Not sure I believe the latter group but I could actually just try it on my running motor and see for myself.
In fact, now that I think about it, I could build the cable system on my running engine and decide then...
Oh, oh.
Just get some small pulleys and rig up a system using the cruise control cable land on the TB. You'd have to go under the TB twice to get it to work and would probably need to use some sort of a spring to take up the slack but if you'd want to stay mechanical I could definately see you innovating some sort of cable system.
As I watched the Broncos sleepwalk past the Steelers yesterday (seriously, how did they win?), I had the LIM at hand and tried to envision how a mechanical port actuation setup might work.
I'm starting with the assumption that it will be cable actuated, so each end requires a different mechanism.
The most basic underlying assumption is that opening the ports can be based on throttle position but that trigger point is unknown, so there must be adjustment in the mechanism somewhere.
I was surprised how quickly an idea coalesced and even put pencil to paper for a quick sketch...it looked completely possible.
Until I realized that the ACV was not bolted on and I was merrily utilizing space that the large assemby would occupy.
Well, damn.
I finally met up with Sigfrid yesterday morning- first time in several weeks.
I'm hazy on details, but for whatever reason, he's moving back to Denver. This means he loses his company car (Audi A8) and upon his return next week, the Z becomes his daily.
That ought to speed up work on the car considerably.
Although it was chillingly cold, we finally got to a few of the piddly two man jobs I've been unable to complete...bled the brakes, for example.
Now viewed in the light of immanent daily use, two issues jump to the forefront (issues have legs?)...
-We determined that the clunk in the rear is definitely the diff. We discussed various options and will have to decide fairly soon what to do.
-The front end shimmies a bit over @70mph (just a guess, remember, no gauges yet) and pulls left under braking. I think the shimmy is wheel balance since it was just aligned a few weeks ago. Least I hope so as that's the easy fix.
The pulling under braking is weird, the calipers were rebuilt and just freshly bled without any sign of problems, the pads are new and the rotors freshly skimmed. Front hub bearings are new and adjusted per factory spec (23ft/lbs, then back off 60°).
Below highway speed and under normal braking the Z drives beautifully but we need to figure this out soon.
The fuel pump whine is annoying but not a safety issue, so it's been tabled till warm weather returns.
The engine runs fine but the electric choke is a PITA and I'd like to swap to manual choke control and be done with it. The Holley electric choke makes no sense to me at all and Z's traditionally had manual chokes (even the 280 center console still has the provision despite being injected), so it's not a radical concept. Sigfrid wants to keep dicking with the Holley, so we'll see.
I am fast approaching decision time on the OMP delete for the "new" engine.
I had pretty much talked myself into doing it but partly based the decision on being able to use the Z while my ECU (sadly, I only have one ECU) is sent out to R-tek. If Sigfrid comes back and dailies the Z, this will be difficult. Another small problem to deal with but not really a deal breaker.
I'm starting with the assumption that it will be cable actuated, so each end requires a different mechanism.
The most basic underlying assumption is that opening the ports can be based on throttle position but that trigger point is unknown, so there must be adjustment in the mechanism somewhere.
I was surprised how quickly an idea coalesced and even put pencil to paper for a quick sketch...it looked completely possible.
Until I realized that the ACV was not bolted on and I was merrily utilizing space that the large assemby would occupy.
Well, damn.
I finally met up with Sigfrid yesterday morning- first time in several weeks.
I'm hazy on details, but for whatever reason, he's moving back to Denver. This means he loses his company car (Audi A8) and upon his return next week, the Z becomes his daily.
That ought to speed up work on the car considerably.
Although it was chillingly cold, we finally got to a few of the piddly two man jobs I've been unable to complete...bled the brakes, for example.
Now viewed in the light of immanent daily use, two issues jump to the forefront (issues have legs?)...
-We determined that the clunk in the rear is definitely the diff. We discussed various options and will have to decide fairly soon what to do.
-The front end shimmies a bit over @70mph (just a guess, remember, no gauges yet) and pulls left under braking. I think the shimmy is wheel balance since it was just aligned a few weeks ago. Least I hope so as that's the easy fix.
The pulling under braking is weird, the calipers were rebuilt and just freshly bled without any sign of problems, the pads are new and the rotors freshly skimmed. Front hub bearings are new and adjusted per factory spec (23ft/lbs, then back off 60°).
Below highway speed and under normal braking the Z drives beautifully but we need to figure this out soon.
The fuel pump whine is annoying but not a safety issue, so it's been tabled till warm weather returns.
The engine runs fine but the electric choke is a PITA and I'd like to swap to manual choke control and be done with it. The Holley electric choke makes no sense to me at all and Z's traditionally had manual chokes (even the 280 center console still has the provision despite being injected), so it's not a radical concept. Sigfrid wants to keep dicking with the Holley, so we'll see.
I am fast approaching decision time on the OMP delete for the "new" engine.
I had pretty much talked myself into doing it but partly based the decision on being able to use the Z while my ECU (sadly, I only have one ECU) is sent out to R-tek. If Sigfrid comes back and dailies the Z, this will be difficult. Another small problem to deal with but not really a deal breaker.
Joined: Aug 2002
Posts: 2,614
Likes: 31
From: Freeland, MI
I hate those electric chokes. They never work right because the temperature changes, they can't compensate for it without being adjusted again and usually open to fast anyways. My brother has a summit carb with one (Holley I'm sure) on a 302, and we dick with it more than it works right, we finally said screw it and just pop the hood and work it by hand.....granted yes its a nusience, but its his play toy and he only drives it maybe once or twice a week during the summer
IMHO, car companies that used a heat spring that sat inside a cavity on the intake and opened the choke on intake heat were the best automatic on/off choke system. They rarely ever failed, and worked like a charm
But, most aftermarket intakes and carbs don't allow you to do it, unless you get really inginuitive and make something yourself
IMHO, car companies that used a heat spring that sat inside a cavity on the intake and opened the choke on intake heat were the best automatic on/off choke system. They rarely ever failed, and worked like a charm
But, most aftermarket intakes and carbs don't allow you to do it, unless you get really inginuitive and make something yourself
Even better IMO, would be a completely mechanical (i.e., cable) actuation, no electrical, air pressure...no nuttin. This could be set up progressively (ports begin to open at say, 40% throttle and are fully open by 80%...obviously just a guess) or all at once (ports fully open at 50% throttle).
i have a few 12 inch cables from a jetski and the linkages, i would just need to build up a mount...
you have ACV cuz of emissions in co?
Joined: Mar 2001
Posts: 31,816
Likes: 3,219
From: https://www2.mazda.com/en/100th/
i recall he moved here to silicon valley, of which is in a bubble, and its leaking. we'll see how badly, but you know its bad when there is a TV show making fun of you. the guys in the show "silicon valley" might as well have been my neighbor, and they gave up and he moved out like 6 months ago.
Joined: Apr 2005
Posts: 3,785
Likes: 30
From: And the horse he rode in on...
Couple of things:
The only flaw in manual 5/6 port operation is that you will lose port velocity at low rpm and open throttle. Unless you are *never* going to floor the throttle at lower ron operation you might as well have wired open ports.
Im might have an S5 ECU you can borrow if you want. I'll check it out this am. PM me.
Im might have an S5 ECU you can borrow if you want. I'll check it out this am. PM me.
The key thing with a n/a rotary in maximizing torque production by maximizing intake charge velocities at all RPMs. This is truly critical for a street drive RX7. If the engine is fairly stock, then the stock factory settings and functionality for things like the secondary injector staging, 6-port staging and variable dynamic intake staging setting are most likely optimal. The S5 setup/method for the control of the intake staging is superior to the S4. Of course this all presumes that the mechanical controls themselves are free moving (not stuck) and functioning correctly.
Now with mods like; a real CAI, a modified intake manifold setup, 6-port sleeve inserts, a header and/or high flow exhaust, you can use the adjustability afforded you by the Rtek7 stage 2 to re-optimize you specific setup. Changing the 6-port controls to a simple RPM based mode without factoring in engine load or even using a manual cable controls setup would be to say the least, less than optimal.
Now for a car with a 6-port engine at the track where you are operating only in the 4000-8000 RPM range, then manually wiring the 6-ports open is understandable.
Now with mods like; a real CAI, a modified intake manifold setup, 6-port sleeve inserts, a header and/or high flow exhaust, you can use the adjustability afforded you by the Rtek7 stage 2 to re-optimize you specific setup. Changing the 6-port controls to a simple RPM based mode without factoring in engine load or even using a manual cable controls setup would be to say the least, less than optimal.
Now for a car with a 6-port engine at the track where you are operating only in the 4000-8000 RPM range, then manually wiring the 6-ports open is understandable.
I see your points, Deacon and cede them all.
How 'bout this...
As I understand it, the ECU signal to the solenoid is a simple YES/NO 12v.
Could that not be used to operate a small linear actuator directly on the port sleeve shafts (most likely through a linkage)?
In other words, why introduce pressurized air into the mechanism?
After polishing the shafts and cleaning the bushings, it takes hardly any effort to rotate the sleeves and the actuators are the choke point, I think. One of them takes decidedly more effort to extend.
A linkage with one power source would mean that both sides would operate identically, which it couldn't have been doing before.
How 'bout this...
As I understand it, the ECU signal to the solenoid is a simple YES/NO 12v.
Could that not be used to operate a small linear actuator directly on the port sleeve shafts (most likely through a linkage)?
In other words, why introduce pressurized air into the mechanism?
After polishing the shafts and cleaning the bushings, it takes hardly any effort to rotate the sleeves and the actuators are the choke point, I think. One of them takes decidedly more effort to extend.
A linkage with one power source would mean that both sides would operate identically, which it couldn't have been doing before.
Joined: Apr 2005
Posts: 3,785
Likes: 30
From: And the horse he rode in on...
I see your points, Deacon and cede them all.
How 'bout this...
As I understand it, the ECU signal to the solenoid is a simple YES/NO 12v.
Could that not be used to operate a small linear actuator directly on the port sleeve shafts (most likely through a linkage)?
In other words, why introduce pressurized air into the mechanism?
After polishing the shafts and cleaning the bushings, it takes hardly any effort to rotate the sleeves and the actuators are the choke point, I think. One of them takes decidedly more effort to extend.
A linkage with one power source would mean that both sides would operate identically, which it couldn't have been doing before.
How 'bout this...
As I understand it, the ECU signal to the solenoid is a simple YES/NO 12v.
Could that not be used to operate a small linear actuator directly on the port sleeve shafts (most likely through a linkage)?
In other words, why introduce pressurized air into the mechanism?
After polishing the shafts and cleaning the bushings, it takes hardly any effort to rotate the sleeves and the actuators are the choke point, I think. One of them takes decidedly more effort to extend.
A linkage with one power source would mean that both sides would operate identically, which it couldn't have been doing before.
, nevermind.
I see your points, Deacon and cede them all.
How 'bout this...
As I understand it, the ECU signal to the solenoid is a simple YES/NO 12v.
Could that not be used to operate a small linear actuator directly on the port sleeve shafts (most likely through a linkage)?
In other words, why introduce pressurized air into the mechanism?
After polishing the shafts and cleaning the bushings, it takes hardly any effort to rotate the sleeves and the actuators are the choke point, I think. One of them takes decidedly more effort to extend.
A linkage with one power source would mean that both sides would operate identically, which it couldn't have been doing before.
How 'bout this...
As I understand it, the ECU signal to the solenoid is a simple YES/NO 12v.
Could that not be used to operate a small linear actuator directly on the port sleeve shafts (most likely through a linkage)?
In other words, why introduce pressurized air into the mechanism?
After polishing the shafts and cleaning the bushings, it takes hardly any effort to rotate the sleeves and the actuators are the choke point, I think. One of them takes decidedly more effort to extend.
A linkage with one power source would mean that both sides would operate identically, which it couldn't have been doing before.
BTW, I had my RX7 at a track day event at VIR (which is a high speed / high horse power track) with 6-port actuators that had carbon locked shafts. My left arm got tired of pointing folks by all day long - not a whole lot of fun. I was pissed and then relieved when I later discovered the problem. Luckily I had a perfectly good complete replacement intake setup to swap in along with new actuators and PineApple Racing sleeve inserts.
Last edited by DeaconBlue; Jan 20, 2016 at 08:40 PM.
I'm away from home, housesitting again (not for S.), so all work on the intake is halted for a bit.
jackChild has called my bluff and offered to lend me an ECU while mine gets sent to r-tek for MOP deletion, so I must decide one way or the other. Really, the decision now is not "if" but when. Doing it now introduces me to the joys of premixing before assembling the new engine and if that's too onerous, I can install the MOP, acquire a stock ECU and carry on as normal.
I'll have a complete/intact intake, harness and vac spider left over, so I have the luxury of experimenting, basically without permanent consequence.
Well, assuming I don't damage the keg, of course.
I have been staring at pics and come up with an idea for a linkage to the port actuators, which is half the equation.
The easy half, I'm afraid...but we'll see.
jackChild has called my bluff and offered to lend me an ECU while mine gets sent to r-tek for MOP deletion, so I must decide one way or the other. Really, the decision now is not "if" but when. Doing it now introduces me to the joys of premixing before assembling the new engine and if that's too onerous, I can install the MOP, acquire a stock ECU and carry on as normal.
I'll have a complete/intact intake, harness and vac spider left over, so I have the luxury of experimenting, basically without permanent consequence.
Well, assuming I don't damage the keg, of course.
I have been staring at pics and come up with an idea for a linkage to the port actuators, which is half the equation.
The easy half, I'm afraid...but we'll see.
Well crap, decision just got more complicated.
A local glass company is clearing out old stock (at least, that's the claim) and is offering a windshield with at home install for $190...I've been bitching about my glass since I got this chassis and that price is $100 under other quotes I've gotten.
I hate to pass it up but the purchase will slow down engine work for a while.
Oh, what to do?
A local glass company is clearing out old stock (at least, that's the claim) and is offering a windshield with at home install for $190...I've been bitching about my glass since I got this chassis and that price is $100 under other quotes I've gotten.
I hate to pass it up but the purchase will slow down engine work for a while.
Oh, what to do?
Well, much has happened...for a change.
The new windshield is installed and I did a minor refresh of the surrounding parts- painted the wiper arms and made a more serious attempt to pretty up the raggedy glass side trim.
There is a problem though.
The installer cut the top rubber trim too short and there's a gap where the l-piece on the corner doesn't meet up. I'll get that fixed tomorrow, I hope. The generic trim he used is slightly wider than stock and doesn't fit those corners too well anyway, so I'm thinking of ordering an OEM replacement and fitting that instead.
Today was spent with Sigfrid, working on the Z.
Now he's back in Denver permanently and is selling the Audi he bought in CA, the Z will soon be his main transpo and he has become highly motivated.
We put the front end up on ramps, loosened all the suspension bits and torqued them down with the weight of the car on the wheels...supposed to "normalize" the suspension.
?
We removed the calipers and pumped them off the rotor so we could verify piston movement.
Everything checks out but the car still pulls left under hard(er) braking.
I'm currently bereft of ideas.
Did the same at the rear and discovered the cause of the rear end clunk.
The rear diff support is called the "mustache bar", it spans the width of the car and two studs on the rear diff cover go through it.
When I went over the diff the first time there were two phenolic washers between the bar and the diff cover...they looked stock to me, so I put them back on.
They had crumbled, leaving about a 1/8" gap for the diff to rock around in...which it did, enthusiastically. The service manual doesn't show them, so we just tightened it up and viola!, no clunk. Dunno what that was all about.
Except for the grabby brakes, she drives quite nicely.
Until S. lands another job here money will be tight, so we're forging ahead as best we can with what we have. Accordingly, we came up with plans to utilize a steering wheel I yarded. I've brought all the stuff home with me and will commence machining tomorrow, I think.
We also decided to once and for all explore fitting the Prelude seats I have. I've been skeptical they could be fitted, but we never really tried until today. Sigfrid was in full power/manic mode and within two hours showed it was not just possible but not bad at all. The only seat at his house was the driver side and it is by far the most difficult, due to the hump in the trans tunnel for the cat (basically, the reverse of the FC), but he got close enough that we're now sure that if the drivers side fits, the passenger will as well.
He's going to continue with that as I machine the steering wheel...I have high hopes.
Weather was beautiful for a change and we had a very productive day.
Good.
The new windshield is installed and I did a minor refresh of the surrounding parts- painted the wiper arms and made a more serious attempt to pretty up the raggedy glass side trim.
There is a problem though.
The installer cut the top rubber trim too short and there's a gap where the l-piece on the corner doesn't meet up. I'll get that fixed tomorrow, I hope. The generic trim he used is slightly wider than stock and doesn't fit those corners too well anyway, so I'm thinking of ordering an OEM replacement and fitting that instead.
Today was spent with Sigfrid, working on the Z.
Now he's back in Denver permanently and is selling the Audi he bought in CA, the Z will soon be his main transpo and he has become highly motivated.
We put the front end up on ramps, loosened all the suspension bits and torqued them down with the weight of the car on the wheels...supposed to "normalize" the suspension.
?
We removed the calipers and pumped them off the rotor so we could verify piston movement.
Everything checks out but the car still pulls left under hard(er) braking.
I'm currently bereft of ideas.
Did the same at the rear and discovered the cause of the rear end clunk.
The rear diff support is called the "mustache bar", it spans the width of the car and two studs on the rear diff cover go through it.
When I went over the diff the first time there were two phenolic washers between the bar and the diff cover...they looked stock to me, so I put them back on.
They had crumbled, leaving about a 1/8" gap for the diff to rock around in...which it did, enthusiastically. The service manual doesn't show them, so we just tightened it up and viola!, no clunk. Dunno what that was all about.
Except for the grabby brakes, she drives quite nicely.
Until S. lands another job here money will be tight, so we're forging ahead as best we can with what we have. Accordingly, we came up with plans to utilize a steering wheel I yarded. I've brought all the stuff home with me and will commence machining tomorrow, I think.
We also decided to once and for all explore fitting the Prelude seats I have. I've been skeptical they could be fitted, but we never really tried until today. Sigfrid was in full power/manic mode and within two hours showed it was not just possible but not bad at all. The only seat at his house was the driver side and it is by far the most difficult, due to the hump in the trans tunnel for the cat (basically, the reverse of the FC), but he got close enough that we're now sure that if the drivers side fits, the passenger will as well.
He's going to continue with that as I machine the steering wheel...I have high hopes.
Weather was beautiful for a change and we had a very productive day.
Good.
The rotors were skimmed and are (presumably) within spec.
We don't get the pulsing you'd expect with warped rotors and I can't see how a slight difference in rotor thickness (I haven't miked them but they are probably different) would cause such an extreme effect.
The brake system is all new/rebuilt...everything.
The only change from stock was the upgrade to a bigger 300ZX booster and master cylinder but I'd think any bad results from that swap would be universal and not focused on one particular wheel.
After the recent alignment, the car tracks straight and steers smoothly.
It takes a determined stab at the pedal to elicit the dive/hook to the left, driving normally the brakes seem great...firm, progressive pedal, no squeaking or weird noises, no drama.
We've checked the calipers (both mounted and off) and the pistons all move in and out easily.
Fully installed, you can feel the pads extend/retract, the calipers pass all my normal tests.
My operating theory going into yesterday was that it must be the passenger side caliper...the driver side wasn't clamping more, the passenger side was clamping less. But they both acted just the same when checked, leaving me bamboozled.
We swapped pads from side to side and no joy.
Having tried all the physical experiments we can think of (and are capable of performing), I've retreated to a Holmesian mind palace to work in my virtual garage. I can't shake the idea this is brake related, despite the lack of supporting evidence.
Natural instinct leads to caliper replacement...a pitfall lined path.
Two things to bear in mind:
-With a mere 130 or so rwhp, we don't need major braking. Why buy capability that can't be exploited?
-The current situation precludes major capital investment (i.e., Sigfrid gots no job), so for the foreseeable future we're stuck with the rear drums and any major upgrade to the front will almost certainly upset the fore/aft brake balance.
The most common/cheap "fix" is the Toyota S13 4-piston caliper- a direct bolt on but Iron Age heavy.
There must be a more elegant solution.
We don't get the pulsing you'd expect with warped rotors and I can't see how a slight difference in rotor thickness (I haven't miked them but they are probably different) would cause such an extreme effect.
The brake system is all new/rebuilt...everything.
The only change from stock was the upgrade to a bigger 300ZX booster and master cylinder but I'd think any bad results from that swap would be universal and not focused on one particular wheel.
After the recent alignment, the car tracks straight and steers smoothly.
It takes a determined stab at the pedal to elicit the dive/hook to the left, driving normally the brakes seem great...firm, progressive pedal, no squeaking or weird noises, no drama.
We've checked the calipers (both mounted and off) and the pistons all move in and out easily.
Fully installed, you can feel the pads extend/retract, the calipers pass all my normal tests.
My operating theory going into yesterday was that it must be the passenger side caliper...the driver side wasn't clamping more, the passenger side was clamping less. But they both acted just the same when checked, leaving me bamboozled.
We swapped pads from side to side and no joy.
Having tried all the physical experiments we can think of (and are capable of performing), I've retreated to a Holmesian mind palace to work in my virtual garage. I can't shake the idea this is brake related, despite the lack of supporting evidence.
Natural instinct leads to caliper replacement...a pitfall lined path.
Two things to bear in mind:
-With a mere 130 or so rwhp, we don't need major braking. Why buy capability that can't be exploited?
-The current situation precludes major capital investment (i.e., Sigfrid gots no job), so for the foreseeable future we're stuck with the rear drums and any major upgrade to the front will almost certainly upset the fore/aft brake balance.
The most common/cheap "fix" is the Toyota S13 4-piston caliper- a direct bolt on but Iron Age heavy.
There must be a more elegant solution.
Is the braking required to get it to tug hard enough that it causes any wheels to lock up?
Do you feel the left pull through mostly the steering wheel or through your butt/the car actually turning left?
I'd recommend taking a good hard look at the lower control arm. Hard braking could be causing the bushings on the left LCA to deform more than the right or the steering rack (or steering components) to shift to the right. Both of these would cause the left front wheel to toe out and pull the car to the left, even though the brakes are working fine. It's unlikely that the right front wheel is the culprit, since deformation on any front wheel will try to pull it backwards with respect to the body, twisting it outwards around the rear LCA mounting. Similarly, the rear end probably isn't the problem, as the car would feel like it's trying to spin, not just pulling to one side.
Do you feel the left pull through mostly the steering wheel or through your butt/the car actually turning left?
I'd recommend taking a good hard look at the lower control arm. Hard braking could be causing the bushings on the left LCA to deform more than the right or the steering rack (or steering components) to shift to the right. Both of these would cause the left front wheel to toe out and pull the car to the left, even though the brakes are working fine. It's unlikely that the right front wheel is the culprit, since deformation on any front wheel will try to pull it backwards with respect to the body, twisting it outwards around the rear LCA mounting. Similarly, the rear end probably isn't the problem, as the car would feel like it's trying to spin, not just pulling to one side.
