Hey guys! First time posting here. Came from RX8club haha. I've owned 4 RX8s so I'm pretty familiar with rotaries. I've been thinking of buying a RX7, but it's questionable reliability keeps me away from it.



To all you cool people out there who has owned both, how different is it to maintain compared to an 8? I've had 8s for 6 years, so if its like the 8, I have no problem buying a 7. I'm just worried if it'll need more care or be different than taking care of a 8. Another question I have is the reliability of the engine. Some say it's not as reliable as the Renesis. Some say it's more reliable. I've seen too many memes of RX7s blowing their engines. I get that they blow when you turn up the boost, but if it's stock, it won't just "blow" out of the blue, right? I'm assuming they gradually lose compression like RX8s? Hot start issues progressively getting worse until it won't start?

Thanks!

 

I have a FD and my daily is an anniversary edition RX8.

It's hard for me to draw a straight comparison in maintenance though. My RX8 is almost 15 years newer than my 7, and I bought it 3 years ago with stupid low miles. It has required some work due to the original owners negligence, but nothing too crazy. For the most part the upfront work and maintenance has been light.

FD is a different story. It did drive when I bought it, but most of the parts were OEM and completely shot/worn out. I spent a couple of years pretty much going through everything someone can go through on it and then some, but I bought the car with the intention to restore it.

I would say with a RX7 you should expect a fair amount of upfront work you should do after purchasing the car. Not necessarily related to the engine, but suspension, wiring, all the rubber components, etc.

I would say in terms of regular maintenance they should be fairly similar if you do any needed repairs upfront.

The 13B will take boost a lot better than a Renesis. You'll still lose some engine life but not on the same scale especially if you stick closer to OEM boost pressures.

As far as catastrophic failures yes they can happen, but that's not any different than the 8 really. You can lose an apex seal or have a coolant seal/wall failure on either engine (as well as many other things).

I'm not an expert like some of the guys on here and on RX8Club, but if you have any specific questions I'm happy to try to answer as best I can

 

Thank you so much! Guess I'll pull the trigger. I just went to see a mint 7. It was leaking coolant from the lower radiator cap. Did some research and found out it's called the AST? It was leaking from the cap.

Another thing I noticed is that even though it started fine and didn't show any low compression issues, it wasn't really fast? It pulled like my RX8. I was expecting it to be way faster. Is that how it's supposed to be? The car had two hks air filters. I'm told that turbos in rotaries have their own air filters?

Overall it was great, it's just that since this is boosted and much more complicated than the Renesis, I'm a bit worried.

 

Yeah if you want opinions on what you are looking at I'd post all of the details and you should get better responses. From what you have said I am assuming you are looking at a FD RX7 (or maybe a turbo FC).

FD has two coolant caps. One is on the neck of the engine between the alternator and air pump, the other is on the AST (small separate tank) which is located from the factory attached to the intercooler. The factory AST is black plastic, most aftermarket ASTs are going to be metal and more of a cylinder shape.

The filler neck cap is not spring loaded, the AST cap is. Neither of them should leak obviously. If the AST cap is leaking it could just be an old/bad cap, it could also be the coolant system getting pressure from the engine (not good).

I would remove the filler neck cap (not the AST one) while the engine is cool, and run the car for 5-10 minutes with the cap off. Look for anything that resembles champagne bubbles. If you see them that engine is circling the drain. Alternatively you could also just get the coolant system pressure tested.

Has the car actually been compression tested? I wouldn't just go off the feel of the engine or anything like that, you want the actual compression numbers.

If it's the HKS pod filters I am thinking of, those aren't really doing you any favors. They just suck in hot air from the engine bay and that can hurt performance. With the pod filters there would be one filter for each turbo. Stock style intakes/cold air intakes will look kinda like the RX8 intake box, and all air intake connections will go to that box.

As far as how it pulls just look at the factory specs for both cars. The 7 is lighter and should have more horsepower and torque than an 8 does. I don't have dyno numbers for my cars, but my RX7 does feel a lot quicker than my RX8 does.

Make sure you aren't just buying off someone else's headache, or at least if you are ok with that make sure you get a good price on it. Cars can look mint and still have tons of sneaky issues.

 

It would be great if you could provide more details on the car.It should accelerate faster than your RX-8 and you should feel the turbo transition if it has stock sequentials. Chance are the sequential system is not working right due to old solenoids or cracked vacuum lines, some people have a really hard time getting the cars to work in stock form or even in a simplified sequential setup. When it works it's really a lot of fun and has a wonderful feel.

An FD will be as reliable as it's owner wants it to be- it all depends on where and how you spend your money. Most of the reliability nightmare rumors stem from people modding in the late 90's and early 2000's in wacky ways.

 

Thanks for the response guys! Its a facelifted FD. The AST is black plastic, so I guess it's original. Coolant was dripping from the cap. The car did not overheat though. No way of getting a compression test where I live. While revving in neutral, the car made a "pshhh" sounds. It wasn't a blow off sound. More like a turbo spool sound? Is that normal?



I've attached a picture of the engine bay and the coolant leak.



The only issue is, it pulled like my 8. I own a WRX STi 7 and I was expecting the 7 to be similar to that. But it was like a 8 :/

 

Yeah it shouldn't be leaking like that. Could be the cap or the AST itself old/damaged, but I would check the coolant system like I mentioned in my other post just to make sure.

As far as the compression test, there is a way you can use a normal compression test tool to do it. I don't have the thread handy but it is detailed on here and I think also on the RX8 forum.

That noise doesn't seem abnormal, could be the blow off valve, or the CRV. Since you don't have the stock airbox I expect their noises would be more noticeable. It could also just be air moving through the filters.

But again, it should feel quicker than a stock RX8 for sure. If it doesn't, it could be lots of things. Engine issues/compression, turbo issues, boost leak, something wrong in the vacuum system or one of the solenoids, electrical, fuel injectors, bad tune (if not using the stock ECU), etc.

If you can verify the engine compression and take a look at the coolant system I think you'll be able to identify or rule out any common major engine problems.

 

A big help will be boost pressure- does it have a boost gauge?

If so what is it reading under full throttle? You should see it hold 10psi boost then a slight dip to 8 psi around 4500 rpm then back to 10psi as the second turbo engages.

if this is working it should feel significantly quicker than your 8

 

Yeah I know the trick. Did that to check a friend of mines 8. You need a slow motion camera for that. Thing is I don't think the seller will be willing to go through all the hassle. I'll get the coolant leak fixed. That doesn't seem major. Only that worries me is that I read about it a bit more, and found out that it can blow and spill all coolant and kill the engine. The RX8s Plastic coolant tank is notorious for cracking and spilling all coolant. Happened to a friends car and he had to replace the engine. So I'm pretty worried about that.

I went to see this car last month and it was backfiring heavily and ran on what seemed like one rotor. He said after replacing the fuel pump, everything was good. Maybe the new pump he chose doesn't give enough fuel?

I think it has a stock ECU.

 

Good point. Sadly it does not have a boost gauge. I watched some videos about how the second turbo not activating properly. It only went up to about 5.7 psi. Turns out he mixed up the connections for the turbos. Could it be something as simple as that?

 

Yes, incorrectly hooked up vacuum lines can cause all sorts of issues.

What are the videos you refer to? Do you have videos of this car? If you go for another test drive it is very easy to hook up a boost gauge to the UIM nipple and route the hose through the window to check the boost pattern