irish44j (Forum Supporter) said:For what it's worth the effective rates on my stage rally E30, which is substantially heavier than your car, are 225 up front and about 200 in the rear (the actual rear spring rates are different because of the suspension setup having them mounted on the trailing arm). What kind of rear suspension does the MR2 have?
Thanks for this, it's super helpful. Eventually I'm going to stop being so pig headed and follow yall's advice.
Yeah, I flipped the names, sorry. by the way if you want some more official description...
https://eibach.com/us/c-113-products-motorsport-springs-accessories-helper-and-tender-springs.html
Don't worry about being on the bump stops, it's not a big issue unless your taking it off jumps. The jolts you'll get with any spring over 250 will be nothing compared to occasionally hitting a bump stop. I've run way lower rates on a heavier car and it was fine (100/150 on a 2900lb volvo). E30's only have like 7" travel so not a huge difference, and we ran 180 in the front for years. The 200's we have on now feel perfect (less nose weight than Josh's car).
lxnm said:irish44j (Forum Supporter) said:For what it's worth the effective rates on my stage rally E30, which is substantially heavier than your car, are 225 up front and about 200 in the rear (the actual rear spring rates are different because of the suspension setup having them mounted on the trailing arm). What kind of rear suspension does the MR2 have?
Thanks for this, it's super helpful. Eventually I'm going to stop being so pig headed and follow yall's advice.
I've swapped enough different springs around that I can appreciate that standpoint lol. A lot of spring rate preferences also have to do with driving style obviously. my spring rates are set up more for stage rally but are still pretty good if not a little bit high for rally cross.
OK, I read the entire spring rate discussion. I have an MR2 (lowered, 250F 400R spring rates, works well on choppy roads but too low and stiff for rallycross), I used to rallycross two other different MR2s, here's my 2c.
For rallycross, I'd take my spring rate estimation math and soften it up a little, especially in the rear. Touching the bumpstops occasionally isn't the end of the world, and my stage rally estimates assume much nastier jolts than you'll typically see in rallycross. The Hoelscher setup is great for smooth surfaces, and in Dirt Rally it's probably better on the perpetually backwards Stratos because it'll keep you from spinning off into the trees, but I think it's going to hurt your turn in on choppy stuff a lot.
From what I remember, rallycrossing an MR2 should work like this: lift and turn in basically simultaneously, get on the throttle and absolutely do not back out unless you need to tighten your line NOW or turn a different direction, repeat. It SHOULD be tail happy, that behavior is your friend when the surface doesn't want to let you turn because it means you can initiate a corner immediately where most other cars have to take some time to set up for it.
Also, do you know for sure your car weighs a full 2200lbs? My '85 is a whopping 2040lbs and doesn't have any really extreme weight reduction, just the easy stereo and sound deadening removal.
For what it's worth, both my AW11 rallycross car and SW20 rallycross car ran on stock springs with really long progressive bumpstops and no sway bars and were quick and controllable that way. Alignment was zero toe and like 1deg negative camber at both ends. Not that I don't think there is anything to be gained with different springs, I'm just cheap!
Seems like all of you are in agreement, so I'm relenting to your knowledge and wisdom, mostly. I went ahead and canceled the spring order, and replaced it with a pair of 200 lb springs. I'm not sure that'll be right, but with 400 lb springs the car had 1.25" of droop. If I half the spring rate, that will lower the front of the car about 1.25" more, which will match the back end pretty closely, no helper/tender springs needed.
200 lb springs is the back is actually pretty close to stock rates. Up front, 200 lbs is close to double the front rates. Hopefully that's enough to counter the lost roll resistance of the front bar. Guess I'll find out at the first event. I predict more springs are in my future.
¯\_(ツ)_/¯ said:Also, do you know for sure your car weighs a full 2200lbs? My '85 is a whopping 2040lbs and doesn't have any really extreme weight reduction, just the easy stereo and sound deadening removal.
No, I don't know that the car is 2200lbs, I've never weighed it. Not much has been done to make it lighter though, but several things have been removed to simplify the engine bay including the AC, and any time I break/replace something, I do so with weight in mind. If I do the simple maths from the amount of droop I have and assume a motion ratio of 1 (I was supposed to measure that), I get 1000 lbs front and 1100 lbs rear of sprung weight, with about 20% error. That doesn't tell me much does it.
For what it's worth, both my AW11 rallycross car and SW20 rallycross car ran on stock springs with really long progressive bumpstops and no sway bars and were quick and controllable that way. Alignment was zero toe and like 1deg negative camber at both ends. Not that I don't think there is anything to be gained with different springs, I'm just cheap!
There wasn't anything particularly wrong with how the car handled on the stock suspension. A smarter me probably would have left well enough alone and not changed a thing.
Speaking of weight reduction, I was kinda planning on doing a bit of that for a while now. This is all really just a distraction while I wait for the new springs to show up.
Currently all the carpeting and interior is in the car, and it really doesn't need to be. Actually, with how dirty this car gets, removing fabrics seems like a good thing. A little way into the trim removing, I came across this little box behind the driver side B-pilar under the seatbelt retractor. This is the dead bug buzzer that goes off when ever you have the door open with the keys in the ignition. Yeah, that's coming out.
I'm not sure what the switch there does though, maybe I can get rid of that. After a bit more fiddling around, and removing the pasenger seat through the driver door because the lift was in the way, I got the carpet on the firewall out. That stuff is heavy. The carpet is lines with some thick plasticy stuff, and then has about 1.5" of insulation as well. Conveniently the carpet is in 3 pieces, the drivers foot well came out after the firewall.
A surprising lack of rust holes on the floor there. Not that I'm complaining, that's a good thing. Next up were the door panels, in the earlier cars they look like this
I do have the window crank and handle trim, but I was already in the process of taking this off before I took the picture. Much like the rest of the interior, these were in surprisingly good condition, here's the back side
I don't want to leave the doors bare since there's sharp edges and such there. The plan is to replace the door cards with some PVC panels. It's not going to save me much weight, so depending on how they come out I might put the originals back on. I have the template mostly ready now
All of the interior panels were in excellent condition, zero of the door clips pulled through the board, which I think is a first for me. Pretty impressive for a 35 year old car. I did break 1 clip on an interior panel, but it was a readily replaceable one. Things like this make be feel a little guilty for tearing a car like this apart to make a it a race car, but I guess that's how things go. On the plus side, if I can ever get myself to be bothered to post them I suspect these interior pieces might actually maybe be worth a little money.
Get coroplast sheets for the doors. They weigh almost nothing and hold up well to abuse.
That coroplast stuff looks interesting. What I have to work with right now is PVC foam which shouldn't be quite as light, but there is still a lot of air in they so they're far from heavy. This stuff does look interesting, if I don't like the PVC foam I could be switching over.
Note: home depot only stocks black in units of like 10 sheets. 10 4'x8' sheets is more corrugated plastic than I will use in a lifetime. Will need to find another supplier
You can find it at sign shops or plastic suppliers.
lxnm said:That coroplast stuff looks interesting. What I have to work with right now is PVC foam which shouldn't be quite as light, but there is still a lot of air in they so they're far from heavy. This stuff does look interesting, if I don't like the PVC foam I could be switching over.
Note: home depot only stocks black in units of like 10 sheets. 10 4'x8' sheets is more corrugated plastic than I will use in a lifetime. Will need to find another supplier
I think I got it at Walmart or something, maybe online...one 4*8. That said, it's amazing how many other uses you'll find for it once you see what it is. If you end up buying 10- pack let me know I will buy a couple sheets off of you for sure
CAinCA said:You can find it at sign shops or plastic suppliers.
Yeah on second thought maybe I got mine at total crafts.....
Progress has been a bit slow lately. I've been slowly working on getting the rest of the interior stripped in no particular order, so the photos below aren't really chronological. At this point, I have all carpeting and the headliner removed. I was a bit worried that this was going to reveal some rust holes in the floor, but that actually all looks pretty good
They sure did put a lot of sound deadening tar in this car. That grey section of the fuel tunnel bump is me experimenting with scraping it off. That piece was pretty loose to begin with, but still fought back. It sounds like some spray freeze or dry ice is in my future.
I was hoping that the frame for the sun roof would be a little more removable, but that's not really the case. The plan is to remove the run roof entirely because a: it rattles and is annoying, b: it's heavy, c: I want as much head room clearance as I can get. Here's the bottom, it looks like it's held in with some spot-welded in brackets.
I don't see any welding around the seam of the frame, which is good. But, up on top I also don't see a seam. It seems like I'll need to do some cutting if I want to get that out
That brings us to seat fitting, there's a nice aluminum race seat to go in, along with some fancy over-engineered mounting brackets. This was a lot of put the seat in, take the seat out. Repeat until the I got the location adjusted so that both me and the wife were reasonably comfortable and could press all the pedals. It took a while.
Initial fittings of the seat with the headliner in showed that head clearance was going to be tight
This isn't really a surprise, head clearance is tight with the stock seat too. We're now back to reason c for wanting to remove the sun roof frame. To get my head to clear, I needed to get the seat as low as the brackets would allow, remove the headliner, and tilt the seat back a little. But, I was able to leave all the padding in the seat, which seems like a good thing. With all that done, I just barely clear
I'd like to tilt the seat more upright, but I'll need to remove the sunroof frame for that. But, we're not done with seat fun yet. Those over-engineered seat brackets weren't quite engineered enough as they're quite oversized.
There's two issues here. First, the bracket is pretty clearly blocking the hole in the seat for the seatbelt/harness. Second, to make it worse, the bracket was laser cut and the edges are sharp enough that they would cut a seatbelt pretty quickly. That seems like it might be a safety issue. You can see the sharpy line on there though, I have no qualms with cutting these things apart, and then the look like this
At the front of the bracket you can see a bit of adjustability. The seat won't slide back and forth on these because of the rear mount I'm using, but I can tilt the seat forward, if I ever get around to removing the sunroof.
Anyway, here's the seat installed and in position. Seat cover is just draped over for now, because I keep having to remove it.
The springs for the front suspension are here already. I actually have one of them installed because that strut was out and I wanted to roll the car back a bit for door clearance. I need to get the passenger side one done, and finish up the door cards.
Great to see the progress and that the Riot Rye is being put to good use! Thanks again for the set of Eibach springs, will be updating my progress later today.
The plan for today was to put the other front spring on, get the seat in, and then take the car for a quick test drive. But, well, one thing led to another, and I sorta kinda the dash
Oops. But, the dash top is made of sheet metal (with fake leather on top) so it's actually kinda heavy. While taking apart the gauge cluster area, I ran into a mysterious plug/sensor, and I wonder if anyone knows what it is. It was floating free behind the gauge cluster, and there wasn't an obvious place to connect it to. The wiring pretty clearly goes into the stock wiring harness, so it's a toyota part whatever it is. Kinda looks like a photo-diode, but that seems silly.
With the dash and glove box out of the way, there was the last component of the AC system just sitting in front of me waiting to be removed. I didn't have to remove the whole dash to get to it, but it sure did help. The AC evaporator was surprisingly heavy, and the box was full of leaves.
I'm not quite ready to remove the fan unit, the car gets pretty hot inside so while the fan doesn't do much it's the best I got. I'm not man enough yet to remove that creature comfort. The heater core is also still in there, I don't want to remove that until I get some sensors to monitor the temperature of the radiator inlet and outlet. These cars have an annoying tendency of getting air trapped in their very very long coolant lines, and the heater is my method of determining if the coolant is flowing. From a comfort perspective though, yeah it can go.
Also related to the fan unit, the MR2 doesn't have a cabin air filter. As a result, there were a much of leaves in the ventilation ducts. I think I'm going to try putting a bit of fabric over the vent inlets to try and keep out some of the dust from the track. It probably won't work. Also the flap in the blower was completely saturated with dust, and the 35 year old foam was disintegrating. Annoyingly the blower unit looks like it wasn't really meant to be serviced, so I'm not sure I'll be able to replace it.
I'm in the process of putting select pieces of trim back on the car now. You can see the HVAC control are still there, and the center consol is staying. Working on getting the gauge cluster all back in place now, but I ran out of time for the day.
With the holiday weekend, I’d like to say I was able to spend 3 fully days in the garage getting work done, but other chores got in the way of that. Still, I did get some work done. First thing I did was finally get off my but and install the new spring in the remaining strut. So, I now have 200 lb springs all around, and the front of the car sits level. Here’s a photo of the current height, it’s still riding a little high (probably a good thing), but no more heavy negative rake.
Following that, I obviously had to take the car for a short test drive. I had the door open for quite a while when I was stripping out the interior, so of course the battery was dead. I should probably remove the 1 last remaining bulb that lights when the door is open so this stops happening. For now, this is what jumper boxes are for. As for the test drive, I didn’t really push anything but turn in felt good, car felt a little oversteery (but I won’t really know till I get to a track), and the butt dyno said the car was pulling harder.
Which begs the question how much weight did I actually remove? I went ahead and weighed all the parts, for science
All that adds up to 159 lbs of crap removed from the car. I then added some of the weight back in the form of a race seat and some paneling, but it’s still a pretty significant weight reduction. Some of you who might have noticed a few items I haven’t discussed yet. So yeah, this happened
I know from experience that the fan doesn’t actually do much. While I want to have some kind of ventilation, I’m not sure it needs to be that. As for the heat, I was keeping that around because I have a mild paranoia about the coolant not circulating through the front radiator because some air got caught in the lines somehow. The thing is that the heater core and radiator lines are separate (and about 1 mile long each way), so that didn’t actually tell me much. I would be better served by an actual temperature gauge on the inlet of the radiator.
The need for ventilation of some sort got me to do something I was kinda planning on doing anyway
This will get me more headroom so I can lean the seat more upright, a place to put a roof vent for ventilation, and should cut some weight all in one swipe of the angle grinder.
In addition to the seam at the top of the sun-roof, the frame is held on by 4 tabs from the bottom, and 1 larger bracket, they’re all spot welded in place. I tried drilling out the spot welds on the tabs, but quickly gave up on that idea and just cropped up the tabs with the cutoff wheel. Cutting the larger bracket was somewhat nerve racking because it sits up right against the roof skin.
After the seam and tabs are cut, the frame is still held in place with copious amounts of glue. A bit of persuasion and the frame comes right out. To fill the hole, I got a 2x3 foot section of aluminum plate from McMaster, probably not the cheapest way to source the metal but they sure are convenient. The sheet metal came very well packaged, and the box/packing weighed significantly more than the metal.
I used some painters tape around the sun roof opening to get the sheet nicely centered. Then I can trace out the opening from the bottom.
The new panel is about 2” oversized front and back, and about 1.5” oversized on the sides. That should be plenty of space to attach things. Since this is an aluminum panel going onto a steel roof, I’ll be riveting it on there. That means drilling a lot of holes. After some quality time with some a ruler, a straight edge, and a drill, I ended up with a roof panel that looks like this
Because the panel is aluminum, I had no trouble at all trimming it with simple tin snips. It actually did a pretty good job. The white thing on there is the roof vent, it opens using a handle on the bottom and is also aluminum. This is going to get painted. The bottom is going to be flat black, so that it doesn’t reflect glare at me. The top will be white, because this car has no AC. The painting is in progress now, but it’s taking forever. While waiting for paint to dry, I finally cut out the door card.
This is palight instead of coroplast, because well I already had some. I think it weighs about twice as much as the coroplast (so twice nothing). Coroplast is kinda like plastic cardboard, with long air holes running through it. Palight is a closed cell PVC foam. There’s a bit less air in it (which is why it’s heavier), but still very light, flexible, easy to cut, and it doesn’t have a preferred bending direction like coroplast does. The door pull is done with tubular nylon webbing meant for climbing anchors, its damn strong. My only issue with the webbing is that it’s also hard to cut, probably by design. Right now, I’d say this is still just a mockup because the screws holding the door pull in place aren’t long enough. If you tried to use the webbing to close the door, you’d just pull it right off the panel. I may also shorten the webbing some, and I need to experiment with other ways to cut holes in it. I’m also going to use the webbing to make some oh-E36 M3 handles for passenger and driver, because race seat.
Well, it seems the clear coat and the color coat I was using aren't compatible with each other, and the paint started bubbling on me. Bugger.
Upon sanding, those bubbles went straight down to the primer and made an ugly mess. So, looks like it's sand it down to metal and start over time. Suck
Way back in 1990, I bought a Miata. At the time, my brother had a 1986 MR2. Several times we swapped cars and drove around "testing". Those two cars were so similar on paper, but I remember the MR2 feeling sharper in handling. Following along to see how this one ends up.
In reply to JoeTR6 (Forum Supporter) :
Except in this case, instead of facing off against the normal platoon of Miatas, I'm up against an army of E30s.
I would be interested in purchasing the fresh air/recirculation control cable from you since it appears that you don't have a use for it anymore
Doug, if you need them I have toe plates to set your toe, down here in Middletown. Nothing for castor & camber, MGBs don't have adjustment for either though you can shim the cross member to adjust castor.
In reply to Mrfurzzy :
You mean this guy here? I certainly don't have any plans to use it
In reply to lxnm :
Yep! I really only need the cables, but would take the entire assembly if you don't want to deal with removing them. It can be a real pain. My email is pfischer968 @ gmail (no spaces)
Things seem to have been progressing slowly the lat bit, but maybe it just seems that way. With the paint in bad shape, I got to spend some good quality time with the sander. And by quality time, I pretty much mean not that. By the time I couldn't feel my hands anymore, I'd gotten about this far
The next morning, I went to the store and got a paint stripping disk for the angle grinder. That worked a lot better. A couple coats of paint later, it was looking like this
I think my engine hoist gets more work as a stand for painting stuff than it does for moving engines about. The paint here isn't perfect, actually it's pretty crap. I'm not that great at painting, and painting big flat things is surprisingly hard. But, this is a racecar, so this is good enough. All it needs is some stickers of questionable taste, luckily I happen to have one
I'm about a chopped sticker short of living the meme, but maybe that's ok. Also, it turns out I'm not very good at applying vinyl and there are some bubbles. My solution has been to just leave the panel lie out in the sun, and that actually seems to be working.
This brings us back to the interior of the car. I finally got around to finishing the driver side door panel. I don't have enough of the red aluminum washers (also of questionable taste, they say JDM Racing on them, because of course they do), so I made the black washers for the door pull and oh E36 M3 handle.
I also clear the roof now with the seat leaned forward, which is good. I wouldn't be under the bottom of a cage if this car had one, but it doesn't so I guess that's ok. Probably best I don't think too hard about rolling the car.
I also got the water gauge installed. It required me to add in a bit of the trim I took out of the car, but not much of it. The backing panel is made of scrap aluminum from the roof, I barely had enough. I blanked off the stereo hole with some scrap PVC foam stuff, which I have more of.
Then began the messy job of pulling out the coolant lines for the heater. This required me to pull all the brackets for the hand brake and some other things. So, I took the opportunity to go ahead and re-install the front half of the skid plate.
I don't think I've talked about this before, the skid plate is just 22 gauge sheet of metal wrapped over a frame of 1/8 steel. The front half extends from the front subframe back to the front engine mount, and 'protects' the gas tank and coolant lines. It's not much protection, but rally cross isn't rally, I don't expect as big of hits.
I then spent about an hour trying to figure out what this thingy is
The reason I care is it connects to the vacuum line which feeds the brake booster, and I wanted to know if I needed to leave it in place, of if it was part of the HVAC and could be removed. I had to do something with the vacuum lines, but what?
Luckily, Toyota includes a vacuum diagram on the engine cover. Of course, there's no brake booster on that diagram, only the stuff in the engine bay. Also, the factory repair manual I have says nothing about this thing. There's seriously no vacuum diagram I can find for the front of this car. Luckily this this is plugged into the electrical harness, and that plug is labeled as a 'water valve'. The water valve for the heater is actually vacuum actuated, and because this car was made in the 80's, the vacuum power is actuated by an electrical switch. It's an amazingly complicated contraption to actuate a water valve into the heater core, I'm surprised they don't break more often.
The gauge obviously needs to actually be connected to a sensor, or it's not very useful. Ideally I'd want it connected to the inlet of the radiator, because the radiator is maybe a little too good at cooling and I want to see the gauge show warm. Unfortunately, the inlet is not very easy to hook into, here's a photo
We're under the car here, radiator on the right wheel well on the left. The inlet hose travels through the driver-side wheel well and into the bottom of the radiator. There's not really much protecting the coolant hose from all the nasty sharp rocks and such in the wheel well other than a flimsy plastic cover. I should probably do something about that, but for the time being the issue is that there is also no room for to add a straight coupling to install the water temp sensor in. There's a lot more room on the outlet side, so that's where the sensor is going.
Here's the sender installed. Yellow line is the sensor, black line is chassis ground. The sensor was meant to go in an engine block, in which case the ground line isn't required. All that's left from here is to add some coolant, and start the car. And then spend longer than I want bleeding the coolant system.
So, I went to do that, and found that the car wouldn't start, no starter solenoid click, nothing. I tried a few little things to get it running, but it was time for dinner and I suspect I'll just make things worse if I keep hacking on it. There's a good chance that the no-start condition is because I leaked a bunch of coolant on the starter cables.
Your making good progress, sunroof blank turned out great!
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