I just blew my motor. It was probably due to running 14PSI with my injector duty cycle near 100%....leason learned. I live on the island of Kauai in Hawaii. There are 2 FD's here, no one knows anything about RX7s so do all the work on my car. I've read the 10 page thread about seals. Everyone said it's all about the tune. I have no tuner here and I am not willing to ship my car to the mainland to get it tuned. Would that 3mm be better for me?

Current mods: Non-Seq, Downpipe, Midpipe, Exhaust, V-Mount Intercooler, PFC, K&N Intake @ 14 PSI. I will be adding a fuel pump and 1300cc injectors to the new motor.

 

you will need to have your rotors machined to fit 3mm seals if thats the way you want to go -- which would proberbly mean you would have to ship them to someone on "the mainland".
iv got 3mm seals in my FD -- the more security you can have against a broken engine the better i rekon.
most people think its all about the tune (im sure they are right, they know a hell of alot more then me!) but i feel if i can get that little bit of extra strength & security (even the possibility of extra strength) then its worth it..for me anyway

 

Wouldn't it be cheaper to invite a tuner on holiday to Hawaii and pay him the plane ticket and free house etc?

thewird

 

2mm seals have been proven to handle over 30psi, 3mm seals are harsh on housings and you would have to send out your rotors for machined to fit 3mm seals if your looking for seals i have some cheap so send me a PM if your interested

 

I have never noticed 3mm seals being harsh on housings? I have seen 2 torn down engines with 3mm seals in the last couple of weeks, both had right around 25k miles on the seals. Housings and seals both looked excellent?

The tune is going to make the biggest difference, but if you are learning on your own I would go 3mm seals. I am using them in my personal engine and that is the only way I would have it. Obviously people have had great success with both 2mm and 3mm seals.

David

 

I've always been a fan of 3mm seals because they are more forgiving. I also have never seen any evidence that 3mm seals are any harsher on the housings.

 

I don't think that is really an option. There are no dynos here either. As far as I know, most tuners only fly down if there are a couple of cars to tune, not just 1.

I'm going to have to tune it myself with a wideband.

 

You can street tune lol. Get a tuner to give you a base map which has ignition and other stuff all done, then just tune afr's.

thewird

 

I am sure if you offer enough money, a tuner would make the trip. Might still be less expensive than popping a motor due to inexperience.

 

Do yourself a favor and run 2mm Aviation seals and get a wideband. Then send me your power FC and I will load a map on it for your mods. Problems solved.

 

From my experience, 2 mm seals hold up better. I know a couple of tuners who would fly out from japan to tune.

 

Are you talking about the unbreakables? Have you torn down any of your engines after 15-20k miles and seen what they do to the housings if that is the ones you use?

 

I have torn down a few of them and no problems with the housings. We took one apart that had 30k miles on it and housings were in great shape.

 

You were running 14 psi on the twins with the stock fuel system? How long did it last like that?

 

A plane trip to Hawaii costs over a grand, then I'd have to pay for his hotel/car/etc. Then for his tune that wouldnt even be on a dyno. That's almost how much a motor costs. I wish I could get a real tuner to tune it, but for that price, I'd rather buy a wideband, learn, and tune it myself. I've already learned some hard leasons from my last motor.


Is there a place that has *current* maps posted? If not, I would be willing to pay someone with the same mods as me a little something for thier map and just do it myself.

4 years and about 50k miles.

 

Thanks, that is great info.

 

Impressive. Current conventional wisdom would suggest that at 14 psi the stock fuel system would be out of gas (as you know by your high duty cycles). Was your fuel pressure solid at those levels?

 

To be honest, I don't know exactly what it was. Im guessing it must have been pefect considering how long it took the abuse.

I hope the 1300cc injectors and a new fuel pump will provide enough fuel this time around.

 

You'll have plenty of fuel Great to hear that you put some hard miles on that motor. Def. get a WBO2, and keep an eye on your AFRs and knocks, especially after a fresh tune. If you have the PFC commander you can make the car run richer very easily if you modify the water temp correction tables. I've used it before and after I put my car on a dyno to make sure it didn't run too lean on the street, and also when I went to the roadcourse/racetrack for the first time. So if you get a map from someone else you can richen the car up until you know what you got.

What you should really do is get an FC-Datalogit box/software and a laptop after you get a map loaded on your PFC from someone who's trustworthy Then you can modify many many more things than you could with the commander, you can log data, keep track of changes, etc. It's great. PM cewrx7r1 (Chuck Westbrook) and order his notes, not sure what he's charging for them thest days.

I've never been to Kauai but always wanted to go there... heard there's some great places to surf. But I can't even think of any roads that you may have over there that you could do street tuning on. I did mine on the street and only in 3rd gear (up to about 100 mph). A fourth gear tune will give you better data (up to 140 mph).

That's pretty cool, only two FDs on Kauai Good luck, but the bottom line IMHO is that there is NO substitute for a good tune. Tough engine parts give you some elbow room, but nothing like a good tune.

 

WaachBack sent pm

 

2 MM or 3 MM is not the central question to ask. both work fine if properly clearanced.

running 14 psi w the stock turbos is asking for a blown motor.

i know you did it.
for a while.

now your motor is suffering for it. some have also gone over Niagra Falls and survived, but it is not suggested if you get lucky to take the trip again.

neither are recommended.

the stock turbo setup is a thermal disaster. i could go on for a number of pages on it. one of the many problems is that the turbo compressor blades start to cavitate above 14. when this happens the air is superheated. gasoline has an autoigniton temp of 660 F. you get any boost spike at 14 psi and you are toast.

further, more psi does not always mean more hp. superheated charge air has less oxygen molecules in it and less O means less HP.

you'd be better off to turn down the boost a couple of psi or go single turbo and your motor will thank you.

hc

 

Isn't RETED in Hawaii? I know there is at least one shop in Hawaii that can probably set you up with a good tune.

 

The previous owner put on 70k miles on the first motor with almost the exact same setup. He changed out the turbos when the first motor went out at 70k. As far as I know, 50k-70k miles is average for a 13bTT motor on stock boost. It lasted for me for that long on 1 bar with a stock fuel system... I would think the extra 900CCs of fuel with a Walbro fuel pump would work out for me. I just bought a street bike the day before my motor blew so this is all I can afford at the moment...


Yeah there are some awesome surf spots here, my roomate surfs 24/7.
There is a 10 mile stretch of open road on the westside of Kauai that I could tune on. It also happens to be on my trip to work.

Really? Correct me if I'm wrong, but as far as I know, there arent any good *rotary* tuners in Hawaii. If there are, they are not on my island for sure.
I think I'd trust myself more before a shop in Hawaii. /shrug

 

Now where's the guy to say, "but so-and-so ran 19 psi" etc etc etc ad infinitum.

 

Here is some additional info. When I had little experience with these cars many years ago I went through quite a few motors. Later down the road I narrowed it down to either a bad map from a supposedly reputable tuner, or a bad power fc. My 3mm motor took a good 4-5 hard knocks before it popped. Every 2mm seal motor I had I never heard any detonation except for once. One minute it would be fine, next minute BOOM with no warning. Had I been more knowledgeable at the time, I would have known that the 3mm motor was knocking and could have let off.

A properly built and clearanced 3mm seal motor will be significantly more resilient and forgiving. This is especially important if you plan to learn to tune. This does not mean that one seal can handle more boost than the next. This is strictly from a durability and forgiveness standpoint. Aside from the slightly higher initial cost due to the milling, there is really no down side to running the larger seals. Some say you lose some sealing ability and low rpm torque. These cars make no torque regardless and the sealing ability is negligible. I only use one place to mill the rotors for me and they use military-spec equipment. I like the Mazda 3mm seals. There are others on the market, but they have not yet withstood the test of time in my opinion. Lastly, I always run premix with 3mm seals. They stock oil injection system does not provide enough oil to lubricate the larger seals. Hope this info helps and congrats for being willing to learn to tune yourself.