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Discussion in 'Hangar Talk' started by Ted, Dec 18, 2020.
More later, but picture now
Cool! Love the Nurburgring poster.
BTW - don't recall if the stickers are still on there, but I used to have arrows marking jack points that aligned with the roll cage down tubes. Minimizes any twisting of the unibody when you jack the car.
I don't think the stickers are there, but thanks for that tip. I'll look for those areas and try to remark them. That would be good to have marked as well.
Yesterday I (finally) put the car up on jacks for the first time. I'd had it up to change the oil and do an overall check of things, but hadn't pulled off the wheels fully.
Overall, not much I hadn't already discovered. The front sway bar end links are shot, driver's side tie rod and both side lower ball joints need to be replaced. Of course the calipers need to be replaced or rebuilt, but I also already knew that.
Strut inserts (front) and shocks (rear) seem dead. The springs of course are older and have some surface rust, but those seem fine.
@Half Fast might be able to answer this best - ther are mounts for a rear sway bar, but there is no rear sway bar. It looks like this might've been due to an exhaust interference issue? Or did the car handle/race better/more neutral without a rear bar?
My friends and I who will be racing this have decided that the Lemons series is what we're going to target for racing this. That seems to make the most sense, among other reasons because it removes a lot of restrictions on equipment used, and the rules do a good job of trying to limit what you spend, but not when it comes to safety. With that, my friend who's the rules expert was going to confirm, but he was pretty sure that EFI was free. If that's the case, we are probably going to ditch the complicated OEM carb in favor of EFI. One of my friends pointed out that on Roadkill they'd just use a carb and points, to which I pointed out that carbs and points comprise about 90% of the problems they have, and EFI has never failed me just from sitting. We're going to look into this further, but I think this might be the thing to do so that we can enjoy race day more reliably. Ultimately that's the goal. There are a thousand ways to lose a race, and the biggest ones are related to not finishing due to a mechanical issue. I am very comfortable with EFI and EFI tuning, far moreso than carbs, and so I think that will also help make things more successful.
It helps to have some direction as far as a race series and thus rulebook, and so my plan is to work on figuring out and ordering the right suspension parts to put in, and then mess with that. Meanwhile we figure out what to do/go with for EFI. Probably doing a carb plate adapter to keep the current intake manifold, which is decent for the engine.
More spiderwebs need to be vacuumed out underneath, but really it's not in bad shape, and certainly not rusted. With the roll bar it has amazing rigidity which is very obvious jacking the thing up.
I'd been somewhat lacking direction of a race series, but I think now that we have that figured out it'll allow things to go easier over the winter to be ready for next year.
FWIW, "Mighty Car Mods" is doing an RX7 right now. Fuel injection is their first project, although I think they're going the "spare no expense" route.
I haven't watched MCM much, but yeah, the "spare no expense" seems to be a little more their route. Even though the car did start up with the carb, it's a sickly carb and also a complicated one. Yeah I can rebuild it, but it's one of those things that just because I can, doesn't necessarily mean it's the wisest route long term.
If you're going to fuel injection, are you allowed to drop in a later motor that already has it? Either a GSL-SE 13B, or something from a 2nd Gen?
Heck, go nuts and drop in a Renesis motor!! (I always wanted to do that, but classing...)
I used the stock front sway bar. Removing the rear sway bar made the car neutral at racing corner speeds (but it would push like a pig at a parking lot autocross). Some folks left the rear bar in place and went to a stiffer adjustable front bar. Some of ‘em were faster than me, some were slower, so “best” is indeterminate and somewhat depends on driving style.
One thing with Lemons is the price limit, and so essentially you need to look at what will count towards your limit and what won't. This engine is (currently) in good shape, so I don't really want to do an engine swap.
However, turns out we were wrong - EFI does count towards the dollars. So we either need to do it really cheaply, or else stick with rebuilding the carb. Given how much work @Half Fast had done to it, the latter probably makes more sense as even a Microsquirt will end up costing more.
Thanks for the details. We'll leave it as-is for now, then.
With the current shocks being dead (and counting towards our dollars on the car), we're likely going to be best off replacing them with cheap KYBs, even though those aren't ideal by any stretch. But with the car jacked up, I can just move the wheel up and down (springs are fully extended) with zero resistance. So, cheap new ones will do better than blow out old ones.
I knew someone who used an RX7 like yours in some sort of slalom/autocross. It was run in a "standard" class.
He said that the rear axle acted as a sway bar due to the geometry of the four links and that this caused trouble. The solution - disconnect one of the top links at the axle end. I drove the car on city roads at normal traffic speeds and it went along fine with it's three link (plus of course the lateral Watt's linkage - I think it was) rear axle.
It had no LSD and inside rear wheel spin was probably a big issue in low gears.
If the calipers need to be rebuilt, I can provide you with a source. He brings them back to as new condition, including plating the castings. His business caters to all brands of performance vehicles and racing, and the prices are reasonable.
I would be interested in your source. Could definitely be good to just mail all 4 off and get them back good as new. Since we’re not upgrading the brakes from factory this shouldn’t count against the spending limit on Lemons.
I'll get his contact info and send you a PM.
Also, remember that on the finishing grid there’s a position even lower than DNF and that’s DNS.
(There might be a life lesson in that somewhere....)
Garage Squad had an episode where they resurrected a 1st gen RX7 that had been sitting for nearly 20 years. Nothing really different than what I’m looking at other than it’s a street car vs a racecar. But I really don’t want to rebuild the carb.
Towards the end of last year I was really focusing on getting some RV projects finished up for our Christmas travel. It worked, seeing as the RV performed flawlessly for our trip and met or exceeded all expectations. But now it's a new year, which means that I can get back to some of the other projects.
The RX-7 is a big one. Last year (mostly because of the RV and the timing of shop construction) we didn't get the thing racing. This year, I want to make sure I get to take it out on the track. We've selected the Lemons series as the target as I'd previously stated, and given that, the car will more or less stay in its current configuration with only modifications being made to get it back up to snuff and working correctly. So really refreshing, rather than modifying.
To that end, I've ordered new suspension bushings for essentially every joint on the car. Many from age are just not in very good shape anymore and dry rotted out, so this will be good to do. I also ordered brake caliper rebuild kits and new rotors, since the calipers were seized up and the rotors were pretty rusted. When I get it all back together, it will essentially be a fresh suspension, fresh brakes, and should be in a good spot. I'm going to put in a new thermostat as well, and will probably order a new radiator to put in just because of age on this one and some signs of corrosion that could result in it bursting at some point. The way I understand the Lemons rules, your budget limitation on it is essentially around modifications and upgrades, and suspension/steering/safety/engine that remains stock to form is "free" as part of that budget.
The rear suspension is more straightforward than the front in a lot of ways. New bushings, leave the rear sway bar removed, new shocks, redo the calipers and put on new rotors, done.
The front will get new bushings, new ball joints. One of the tie rod ends is loose and otherwise the steering is pretty tight and seems fine. So, I will probably double check it and then limit replacement to that one tie rod end. The front strut inserts I have to figure out as well what to do for replacements there, since Tokiko is now out of business. But that's really the only more questionable part of what to do.
The carb rebuild is the one item that needs to be done, and that I also am rather dreading to do. So I'll put that off to last. I know the engine runs, and now that I know that I can go through a number of other items in the car to help prep it. As I get closer to the suspension being rebuilt, I'll get some new tires ordered for it, and then we'll be set to drive it and see how she does.
For how simple the car is, it really shouldn't be too bad overall to do now that I'm finally getting around to it.
Be cautious with the front brake rotors. I had problems with cracking rotors that weren't manufactured in the US or Japan. Some people had their rotors cryo'd and said that helped, but I never tried it.
When they crack, it's possible to lose a large chunk out of the rotor and have the caliper and pad jam the rotor, locking the wheel. Having this happen when entering a corner at 140mph results in a "bad day."
Notice that the front brake cooling hose attaches to a can at the rotor that is shaped to direct air to the center of the rotor. You need to supply the cooling air to the center and let it be drawn up through the vented rotor to get even cooling. If you apply cooling air to just one side of the rotor, the temperature delta across the rotor will cause it to fracture. The current method also provides some cooling to the wheel bearing.
Lots of devils in the details.....
Yeah, I definitely am paying attention to that aspect of it. I don't think that Lemons races on tracks that end up being hugely fast, but still something that we want to avoid. And I fully intend on keeping the brake cooling ducts that you left in there, and trying to make sure they're doing what they're supposed to.
Since I already know the engine still runs and the suspension is pretty straightforward, I think being ready to race this year is practical.
I'll go ahead and put this out here. I took a look at the Lemons schedule, and I see a lot of races that are within ranges that I would consider. A benefit to living in the middle of the country and being a road warrior is that my definition of "close enough" is pretty broad. Right now, I'm not targeting any races in particular. But the following races look like potentials. Although NJ and CT are a lot further away, I have a lot of friends and my mother in New York, so I may consider the longer trek.
Louisiana (NOLA area) March 26-27
Pittsburgh April 9-10
Deer Trail CO (just east of Denver) June 4-5
Millville NJ June 11-12
South Haven MI June 25-26
Thompson CT August 6-7
Joliet IL Aug 13-14 (near Chicago)
Deer Trail CO 24 HOURS!!! Sep 10-11
Bowling Green KY Sep 24-25
South Haven MI Oct 8-9
Angelton TX (near Houston) Nov 5-6
Road Atlanta, Dec 10-11
I'd really like to make the 24 hour race (especially since that's one of the closer tracks to me) if the car seems like it's holding up well and I get enough races in to feel like it should work.
Right now I have some friends who've expressed interest, but no particular race crew that seems like it will actually come together with any sort of reliability. So if there are folks from here who are interested, I'll make sure to announce where I'll be racing and we can see about having a POA race team.
@Half Fast gets first dibs on driving it... after I get my laps in, of course.
Bowling green and road Atlanta are certainly possible!
I fully expect the MC to provide a generous donation to the POA race team for sponsorship.
Parts should arrive sometime this week to allow for some weekend wrenching on the RX-7. This is exciting!
From what I'm seeing at the moment, we should be in a good spot as far as the $500 limit on the car goes. So with that, I think the goal is going to be to find a carb upgrade rather than rebuild this one, more than anything since it's a complex carb that's not hugely well supported. If anyone happens to have a smaller (500-600 cfm would be ideal) Holley double pumper (mechanical choke preferred) sitting around they'd sell or donate to the cause, I'd be interested.
Ted, have you contacted Mazda Motorsports yet? When I was racing, they sold new parts to me for less than they charged Mazda dealerships. Plus they offered contingency money for finishing positions in some races.
I had to register with them and send pictures of the race car. Might be worth checking into. I don’t know whether they will still support that old a car.
This! I had the same experience while I was racing my spec Miata.
Plus they gave me a really cool Mazda Motorsports racing jacket, which @2-Bit Speed has now.
I had forgotten to check into that, thanks for the reminder. I went to the website, though, and since I don't have a membership in any race body, it looks like I don't currently qualify. They don't list a limit on year of the vehicle, so my guess is they would still allow the car. I may call up tomorrow, explain the situation, and see what they say.
I managed to get a little time actually wrenching on the RX-7. The end link bushings probably would've lasted just fine, but I decided I'd replace them anyway. Everyone on here knows how I overmaintain things.
With me basically replacing all the rubber components, the suspension should be in a good state.
The radiator arrived as well today, that looks like it will fit. While the old one wasn't leaking, I'm trying to follow the strategy of "the easiest way to lose a race is not to finish", and trying to make sure that it'll be reliable.
Another interesting thing to consider carb wise would be the cheap Chinese Weber clones:
“Radiator” reminds me. I seem to recall that I had to go to a higher pressure radiator cap.
That's a lot of races to choose from. I think the most races I ever did in a season was nine, the first one being at Sebring in January and the last one being the SCCA runoffs At Road Atlanta, which is my home track, in October. Those were all sprint races and I do recall it being pretty much all I did, other than work. After a couple of races you'll have a better idea of how much a race weekend impacts your family life, and then you'll know how many races you'll want to do.
The only enduro I ever participated in was a six hour one in the IMSA Racing Stock series back in 1979. Our crew was very solid , we had one somewhat minor mechanical problem, and finished 18th out of 62 cars. A six hour race is more like a long sprint race in terms of what is required of the car and crew. We were able to use one set of brakes for the entire race, and nothing significant broke. If you're really thinking of doing a 24 hour race, you'll need a big pile of spares and enough crew and drivers to where they can rotate out, you don't want someone who is tired and sleep deprived changing brakes in the dark. If you're serious about trying to be around at the end of that long of a race, you'll need the ability to change or rebuild quite a lot of the car, which will require enough skilled crew to be ready to fix what breaks, very possibly in the dark in the wee hours. These crew would preferably be local to you so that they could become familiar with the car.
If you need crew I could probably make NOLA, possibly Bowling Green, and Road Atlanta. December in north Georgia is a bit of a roll of the dice, weather wise, it could be 70 degrees and sunny or 35 degrees with a hard rain.
I definitely don’t think we’ll make all of those races, it’s just that those are the ones to even consider due to distance from home. Part of why I like the endurance races is 1) that’s more my style anyway (reference the 10+ hour flying days for Cloud Nine and numerous road warrior trips 2) there’s a lot of racing that goes into one trip for probably a similar time investment otherwise, so getting more experience and more of a fill.
How many we do, we’ll see. My wife is fully on board with the whole thing and wants to drive too, so that’s a good start to things. We’ll see how it all works out.
Racing is more exhausting than you might expect, so you might want to find shorter sprints for your first race or two. Especially while you’ll be working the bugs out of the car.
If I can find something more local, I'd definitely do that. But Lemons I think ends up being the goal.
I'm also leaning towards actually registering the car. In Kansas it's old enough to register as historical, so it wouldn't cost much to do, and gives me some more flexibility. While I obviously can't test it to race level driving, that'll let me do some basic miles to make sure I'm not chasing stupid things on race days.
I can see the next thread coming now...
"Thinking about buying a race track"
A friend of mine pointed out that our property, at 11 acres, has enough land to build a racetrack. Of course it'd be dirt.
Dirt is for farming. Pavement is for racing
That's the thought I have, at least with this car.
Chili Bowl Nationals/World of Outlaws/Tony Stewart would like to have a word with you, lol.
LOL! Actually, I love watching sprint cars on dirt. But as a driver I'd rather be in a sports car on a road course.
Why? Just pave the whole thing. Now you have a property suitable for a racetrack, autocross course, runway... If you like green, then paint it green.
Are you paying the concrete bill?
Dude, I spend all of my money just fine, and I have a wife to take care of the remainder. I'm just trying to lend you my expertise in the matter.