jimlab

A) because cutting requries repainting, and B) because you don't want a thin edge, sharp or otherwise, where the tire could meet the fender.

ptrhahn

iTrader: (9)

There's no reason not to roll your fenders. IMHO any FD with aftermarket wheels of virtually any description and/or lowered should just be rolled. The front fenders wells are small, and all it takes is a good transition with the wheel turned, and you bought a repaint.... just go for it.

You don't want to just cut the lip off, because it adds structural integrity.

FDNewbie

iTrader: (10)

So you don't experience any paint chipping/cracking when you roll the fenders? And yea I figured the sharp edge might not be a good idea...

David Hayes

iTrader: (6)

Cam (Pettit) suggested that I roll the lips. They have a device to do this in the shop. Doesn't matter that much if the paint gets chipped as I am repainting the car anyway. Cam is going to install ceramic seals in the car for reliability. He also states that I'll get much horsepower. In fact, at 7 PSI, he says I'll make.....oh, that's right, don't want to touch off another round of debates! Seriously, he's going to dyno the car when done and I'll post the results. He's done a few of these and the numbers (I've seen the dyno results) have been quite impressive. And yes, the single turbos get more horsepower but they don't make the power until higher up in the band.

RedR1, good to hear from you. Refresh my memory - you have a 20B in the car? If so, how's it working out? Dynoed it?

David Hayes

iTrader: (6)

Pics of car before the 20B conversion

FDNewbie

iTrader: (10)

So David...are you going w/ twins? I'm guessing Pettit rebuilt/upgraded/reworked twins? Sequential or parallel? (Forgive me if you've already answered this earlier in the thread...I must have forgotten)

ptrhahn

iTrader: (9)

You shouldn't if done right... they'll need to use a heat gun to heat the paint.

RedR1

iTrader: (5)

David, I wish I had the time to send my car off for 90 days, but at the moment the old lady has the Scion and I the FD and we both work on opposite sides of town. When I pick up a decent daily driver, then I may, depending on my financial situation when the time comes. Im still running the 13B for now, but I have non-sequential twins, Greddy piping, Panspeed pulley kit, downpipe, resonated mid, and the GReddy Ti. A couple of other things like ecu, the usual goodies. Only thing that changed since last time were the pulley's, bridgebar and catback. Its great to see that you went ahead with the 20B, congrats!! I can't wait to see the beast when the time comes!

David Hayes

iTrader: (6)

FD Newbie, for now I am going with the twins (sequential set up). Cam rebuilds them, including new cartridges, smoothing out the surfaces, blueprinting, and ceramic coating them. Depending on the performance of the car, I may swap over to a single, but Cam insists the low end torque will be much better with the twins.

RedR1, look forward to hooking up and swapping modification stories with you once the car comes back.

FDNewbie

iTrader: (10)

Ohh...nice. So he IS running them sequentially! Do you think you'd be able to find out what EMS he's using to control the twins sequentially...plus how much power they're good for? We've been going back and forth about this on another thread...hehe

I know the website says 550hp, which is prob somewhere around 480rwhp...but that doesn't say at what boost. Also, I'd love to know what's the max hp you can make off the twins (w/ engine port and all the other bolt ons eg. exhaust, IC, etc etc that come w/ the Banzai conversion), again at what PSI. I *really* wanna know if you can break 500rwhpw/ sequentials! . Lastly, we were trying to figure out how he could be running the twins sequentially, since we didn't come up w/ an ECU that could control a 3 rotor AND has the pattern for sequentials...

Thanks a lot
~Ramy

jimlab

Don't waste your money on ceramic seals, they won't last any longer than standard seals under detonation.

FDNewbie

iTrader: (10)

Soo....they're better for what exactly??

bigmack000

said to better for ware but if you det they will shater and eat up the hosuign and turbos.

david i say jsut stick with the stock mazda seals
joel

FDNewbie

iTrader: (10)

So the Rotary Aviation (unbreakable) seals cause extensive housing damage since the seals won't break, so the internals take a toll...

The Ceramic seals wear less, but shatter destroying your housing and turbos...

Stock seals will save your housings (and hopefully your turbos), but will break easily...

Sounds like you're screwed, you're screwed, although stockers will prob keep costs down, since replacing just the seals is much cheaper than housings and turbos...

Lemme ask this...other than detonation, what else is a possible reason for a blown engine? Because if you could ensure you wouldn't detonate (say, a well-tuned WI system, and possibly a very accurate MAF sensor ), the ceramic seals might actually be the best way to go, no?

bigmack000

umm first the stock ones aren't that bad. i know guys who were running tons of boost on them. but when they go they can also eat a housing depending on how lucky you are lol.

othere then detonation what eles can blow a motor same thing that killed mine over heat and blow a coolant seal .
apex seals are the bigges choic and also have a huge riff in the foums lol. 2mm 3 mm no 2mm no 3mm lol never ends lol. iam goin with stock seals on my rebuild. thats my pick out of the bunch.
joel

jimlab

ANY (and I do mean ANY) seal that breaks and comes loose in the housing (as opposed to just cracking) is going to cause damage to the housing and rotor unless you are INCREDIBLY lucky and it immediately exits the exhaust port. Furthermore, it is INEVITABLE that it will cause damage to a turbo as the pieces pass out the exhaust. There is nowhere for pieces to go other than through the blades of the turbine.

No. What would be the point of spending a couple thousand dollars on seals that you will likely never reuse? Turbocharged rotary engines don't often "just wear out", and for the price of the ceramic seals you could buy several dozen sets of stock seals. You'd have to reuse a set of ceramic seals several times for them to pay for themselves, so what's the point unless you're just looking to brag about having them?

FDNewbie

iTrader: (10)

Wow...that sucks. So are stock seals more likely to just crack rather than break apart? (or any other seal for that point)? And I'd think that the Rotary Aviation seals give you the opposite problem...they won't break, so you'll save the turbos, but you'll prob. destory your housings pretty badly, no?

I didn't know you could reuse the ceramic seals. And you're right...if they can still crack and destroy your housings & turbos, the cost outweighs the benifit provided.

DCrosby

Wow I actually get to disagree with Jimlab !!!

If you're very lucky the piece of the apex seal will exit the exhaust port, and if you're standing on the turbo when it happens, it might exit through the wastegate, hence bypassing the turbine... but at that point you might as well purchase lottery tickets !

I was lucky in that it exited through the wastegate or didn't touch a single blade (unlikely) but it did scar up one of my housings.... so I decided on the rebuild as opposed to lottery tickets

But the turbo survived...

RX-Heven

iTrader: (1)

Not entirely true. Carbon seals for example, but those are for na applications.
Others seals will 'almost' always destroy your housings. I know a few lucky people, including myself...once.
They can also exit the wastegate. If the peices are small enough, they will pass through the turbine wheel without damaging it.
I know there are people out there that have trashed the turbine wheel as a result of popping seals.
I've popped two engines, never had a problem with the turbos. Had steel 2mm and 3mm seals in each case. Actually, I don't know anyone personally who has trashed the turbo because of this. Maybe we were all lucky.
Ceramics on the other hand, since they are harder and not nearly as brittle as other materials, do not shatter into so many small pieces and it's these harder and larger pieces that destroy the turbine wheel.

Better sealing characteristics, more power and torque with all else being equal. Less wear on the surface of the rotor housing.
They DO hold up to detonation better than other seals. They are not immune to it though and nothing will ever be.
Believe it or not, some people actually tear these engines apart for no better reason than to change port design, use different compression rotors, replace coolant seals or just for the hell of it to name a few things.


Certainly no one on this forum is more qualified than you to make a point like this.

Stock 2mm seals work just fine for just about everyone.
Some people just want that extra edge in performance and reliability and do not worry about the cost. Am I right Jim?

On another note, the Rotary Aviation seals might seem like a good deal since they have apparently taken care of the manufacturing flaws. We took a hammer to one of them and it marred instead of broke like other seals. This could be good and bad. They may be more resistant to detonation as they claim, but the material is softer leading me to believe they wear faster. If it sounds too good to be true....

David Hayes

iTrader: (6)

FDNewbie,

Regarding your questions about the sequential twins, I'll find out for you. I would be surprised if you could make 500rwhp on them though. The 550 in the Banzai IS at the flywheel. I'm also going to get dyno runs at different PSIs but I'm certainly not going to have Cam run them at max. I'll leave that to a more brave soul!

As for the ceramic seals, Cam runs them in his GT race car and has for a while now with no issues. As he's the "man", I'm going with his recommendations. FYI - my 2 rotor Pettit engine has 3 mm seals in them and the engine ran great.

David Hayes

iTrader: (6)

FYI - I am by no means an expert in any of this, including the seals. I'm also not interested in bragging rights, just want to have a very kick a** sleeper car. Cam has nver "hard pressed" me on anything. I've learned over the past few years to take his advice. It hasn't failed me yet.

Red-Rx7

Your car will not be a sleeper.

FDNewbie

iTrader: (10)

RX-Heven, so the ceramic seals can withstand detonation better than stockers, but since they're not as brittle, they're more likely to take the turbos w/ 'em when they do eventually break? That's one hell of a tradeoff...

Oh David, I'm definitely not asking you to run your car to the max just for my curiosity lol. But I know Pettit cares about reliability much more than max hp #s. Everyone I've heard of who's running a Pettit ECU, Pettit engine, and/or Pettit turbos has had them running hard and strong for years. So I'm sure the 550 flywheel is very reliable. That tells me that there's still more room to play w/...ie they can make more power, but prob. above Pettit's comfort zone, and maybe even against his advice?!

David Hayes

iTrader: (6)

I ran the Pettit street ported engine, turbos, and ECU flawlessly also. They fixed my WOT problem I had that my Jax FL tuner could not find.

I'm sure that Cam could get more from the engine but if you have ever talked to him, he's scary when it comes to reliability. That's his number one concern. I've heard more lectures from him on this issue - he builds for this and for fun also. If you talk to him enough, you'll learn that he beleives that 350-375 RWHP is about all a daily driver can and should have. He'll build them with more horsepower though, if you press him enough. Hate to quote horsepower after all the discsussion on this thread, but I spent some time yesterday speaking to Cam about a single turbo versus the twins and opted for the twins. He just got through building a single turbo (forget which one, T66?) with a 20B that dynoed at 465 RWPH at 12 psi. Cam states he talked the driver into backing down the psi to 8 or so - felt that 400 was the max for a daily driver (of course if the driver is like me, he'll set his "hi" boost setting to the max horsepower and not tell Cam!).

I'm a novice at all this stuff (have owned my FD since I bought it new in 94, but just started modding it about 3 years ago) but I'm pretty good at judging bull**it (many years of business have taught me this). Pettit and Cam are the real deal. I'm sure it can be done cheaper elsewhere, but, for me, it's more important to have it done right.

c00lduke

I second that one very much so, you will have 335s in the rear and your car will sound mean. By no means a sleeper. Stock RX-7s i wouldn't even really consider a sleeper.