So the car is a 1999 RX7 RS, Chaste White. 400hp, Single turbo (HX40 Super), but from the outside it looks very clean; just a little lowering, spoiler delete and some BBS's.

I was blasting along at 12psi / 7k rpm and yeah, something broke. Felt and sounded like I dropped a cylinder, but that's pretty unlikely.

I suppose it was an apex.

Only 70,000 Km since last rebuild so it was a little earlier than I was hoping, but it's not as if I baby it, so I suppose it's fair.

Hopefully no housing/rotor damage or turbine destruction, but I'm not holding my breath.

While I'm mechanical enough to do a rebuild myself, there's a really good rotor specialist in town so I'll get it done properly - though they gave me a ballpark quote of $4500 - $9000, they won't know until they open her up.

So yeah I suppose I'll have to bridgeport since the engine will be out. I don't really need the power, 400hp is plenty of fun for the street, but I need that sound. I want to keep the exterior as original as possible - (why mess with the most beautiful car ever made?) so porting is one of the few ways I can customize it.

I guess I just wanted to share/ discuss, but I do have a few non-urgent questions (I'll find out the answers soon enough).

How likely is it that the internals are damaged? I'm not even sure what seals the previous owner was running, but probably standard.
After it broke, there was a very strange sound, as if the car was dragging a piece of wire behind it. There was no wire. Is that a seal spring thrashing round or a damaged turbo or what?

I love these cars, I've wanted one ever since I was 16. Had great times with it, and it gets huge respect everywhere it goes. Until it's fixed I'm driving a 3 speed auto, 600cc 3 cylinder, red Daihatsu Mira - It's quite the shock to the system.

Anyway thanks for reading.

 

We can only internet speculate, but I don't disagree with a blown engine. If it was a hard seal...and it sounds like it was, then it's unlikely that you don't have damage to the associated housing, irons and probably turbo. It's just a question of how much. It also sounds like a tuning failure, not a high kilometer failure. A properly maintained and tuned engine that's not bagged should last more than 70,000 k (~42,000 miles) IMO.
As for porting, if it's street driven I would think again about a bridge. You might like the sound (definitely a personal taste issue there), but it's intended for high rpm track and you won't see any performance gain...and probably lose performance in low rpm. Exhaust stink and fuel economy...I think even fuel dilution of oil also become issues. I recommend some searching and reading.

 

i wouldn't do a bridgeport either, needing premium fuel and the bridge guzzling it down you won't be doing yourself any favors at the gas pump and for very small gains in power and in a range where you really shouldn't be pushing a turbo engine to anyways(my bridges hadn't even peaked in power by 9k RPMs, but the seals tend to chatter at such high RPMs and eat the housings). is it worth it for the "brap'? never has been for me, after building many for customers i still have no desire for it solely for the aggressive sound alone. a 4 port n/a all motor build perhaps, but that's a different beast, since the non turbo engines don't have the benefit of a turbo.

i rev cut turbo engines with metallic seals at 8400RPMs, only ceramic seals and a balanced rotating assembly should be taken higher regularly and ceramic seals are not a good mix with a turbo engine due to their fragile nature.

 

Thanks for your input guys. I appreciate you advising me not to bridgeport, it is genuinely good advice. I know it's pretty fucked to bridge an engine when I'm not even looking for more power, but it's just something I have to do.

This isn't something I've suddenly decided.. I've wanted a bridgeported 7 for a long time. I know my fuel economy (such as it is) will go out the window. I know the drivability will suffer. I know I'll be leaving a trail of unburned fuel vapors wherever I go, but to me, it's worth it.

The top end power will certainly be welcome, don't get me wrong, but it's basically just the cherry on top - I really want that true rotary tone. Always have. I would have done it earlier, but couldn't justify the cost. Now I can. Silver linings huh?

As for how/why this happened, I suspect there could have been a loose connection to the fuel pump, and that caused the engine to lean out for a few expensive seconds.

 

Welcome! I've talked to a number of FD owners in NZ with bridges, and most say it makes for a terrible street car. A Half bridge is a popular compromise.
Here's a good local facebook group where similar questions have been asked, https://www.facebook.com/groups/220548714806034/

 

Do a compression test then you can kind of get a gauge of what might be wrong hard to tell until everything is apart. I would go street port a little more reliable and more quiet. More of a sleeper set up and depending on what turbo kit you go with is gonna tell you how much hp you will make.

 

for a rotary, can you tell if you have a single bad apex seal? once you get a few revolutions, wouldn't the other good apex seals allow for normal compression on the other chamber?