Are 3mm apex seals better than 2mm?
 

Well, I am going to buy a re-man motor for my fd and was wondering if 3mm seals are better to install than 2mm seal. reason I am asking is that I am thinking on getting the new motor street ported by KDR asnd also they metioned 3mm seals and other mods that go along with there package. KDR said this will increase relability. Is this true? Is KDR a good place to deal with for my car or should I look somewhere else? if so where? thanks.:p:

if the rotors aren't too worn in the seal grooves to be able to run the right tolerences with 2mm seals then GO WITH them. there are some good reasons that mazda produced the motors with 2 mm 3 piece seals in them

regardless of anythingelse you read 3mm Seals are a fisx for worn out rotors - they DON'T seal as well, are harder on the rotor housings, and are not any less prone to brakage from detonation.

As to the Poll - The FD (R-1) set the fatest production car lap ever around Willow Springs when tested in 92. But the Supra is a better drag car mostly because it launches better off the line.

KDR is one of the Best rotary shops in the US/Canada, However Most the FD motors that run "stock" boost (less than 16psi) blow Water Seals not Apex Seals so 3mm Apex seals are just expensive overkill. If you plan on running big boost (20+psi) then 3mm seals are probably worth it. though lots of the dragracers run mega boost on 2mm seals.

Geez, what does the poll have anything to do with the subject???

3mm is only for worn apex seal grooves, and you want to "salvage" to rotors, or for those who have no clue how to tune the engine and want a slight bit or margin of safety.


-Ted

I think the main justification for 3mm is detonation or if you have worn grooves that are out of tolerances. OR if you are tuning your engine and don't know what you are doing and you are too lean under boost. I can't say since I don't have that problem. It seems to make sense that the thicker seal would handle more impacts of multiple detonation waves then 2mm before a crack develops. The same can be said about a seal that is worn from top to bottom from many miles will crack/fail MORE easy from one extra detonation.

So those 3mm are going to protect your side seals too? And in the mean time you have a less quality seal. If you can stick with 2mm 3piece.

when is the last time a SIDE seal cracked from detonation??
Sean

nitrous sometimes can be the cause of side seal breaking....
or using higher than normal side seal spring tension...

explain how nitrous would cause this.
Improper tuning of nitrous usually causes detonation, which would mean apex seals.
Only thing I can think of is maybe from the shock of the hp instantly.
Fill me in?
Sean

Thats not what dentonation is exactly, its shock waves bouncing back and forth through the chamber. ITs not combustion, its a explosion. Good combustion is a smooth flame front orginating from the spark plug area and spreads from there in all directions. Detonation is a violant version of this, thats why you hear rattle like noises because the shock wave is going back and forth quickly from apex to apex and thus quickly damages things.

No kidding? I didn't know that....:rolleyes:

Detonation also breaks the apex seal, and not the side seal. I was asking how nitrous would break the side seal.
A nitrous system doesn't have to detonate to break something. 200 hp instantly on and engine is a lot for the engine to handle.
Sean Cathcart

That's the first time I've ever heard that. Supra's suck off the line, the only thing there good at is makeing big HP easly. They do handle ok for a big car, but they dont have that go kart feal like a real sport's car.

As far as the apex seal's go, if you dont have 3mm seals then of course your going to come up with all sorts of justification's why you dont need them;) Better safe than sorry:)

Wow, the bias of the board is showing through in that poll :o:
Vr-4s(97+) and supras have both seen 13.0 stock. They are the fastest in stock form.

I don't need to own a NOS sticker or flourescent rim lights to realize they are useless.
Better safe than sorry? I would just rely on proper tuning. Detonation will break 3mm selas two, you just might get an extra one or two chances.
3mm seals are for those reusing trashed rotors and those who can't tune properly. (as a generalization, excluding true race applications)
Sean Cathcart

3mm aren't as RPM-friendly as 2mm.... ENOUGH SAID.

The answer to the poll depends on what you mean by "fastest", but it is probably safe to assume quickest 1/4 mile is the answer you are looking for. The shoot-out in the July 93 Motor Trend ranked them like this for that category:

Supra 13.4@106.7
300ZX 13.8@103.9
NSX 13.9@100.9
RX-7 13.9@99.7
3000GT 14.0@99.4

My RX-7 bias is forcing me to think that they got an uncommonly strong 300ZX for that test. In a similar shoot-out in April 92, Motor Trend got these numbers:

RX-7 13.8@101.1
Corvette 14.1@99.9
300ZX 14.2@100.6
3000GT 14.3@96.3

Obligatory RX-7 chest-beating: the RX-7 in the second test was 1.2s faster than the next fastest car (Corvette) at Willow Springs. The NSX, 3000GT and 300ZX followed in that order.

VR-4s run 13.0s? I think they got a power boost at some point after 93 (as your 97+ suggests), but it doesn't seem like they could have made up that much ground with a modest bump. My vote for "fastest" is the Supra.

I will not recommende them. If you follow up with Racing Beat they dont recommend retro fitting any seals that were not in the original engine

What about if you want to run high boost (16psi+) would 2mm seals handle it???

Easy, I have written about this on length here many times.

2mm have less friction than 3mm = MORE power as less is wasted on turning the engine. Late model engines also had the side seals reduced in thickness for the same reasons ! No one changes the side seals for high boost !

It is not needed, and will provide less power compared to a 2mm sealed engine.

You can run a 2mm stock mazda seal in 13B capacity to over 700BHP, has been done by lots of shops in the world.

Keep to accepted limits, Thermal and Mechanical and you will have no problems...and you will make more power with less boost on the 2mm engine :) I know that, is why I changed from 3mm seals.

3mm vs 2mm.. 3mm was yesterday's seal 2mm is today's seals.. we could go on and on about this 3mm vs 2mm topic, but the truth of the matter is that a 2mm well tuned will do the job for serious horsepower, been there. 3mm is a little more tuner friendly. But 2mm will get the job done.... Just tune right. timing + octane+ a/f+ = a happy 2mm seal.......

i went with the one piece 3mm ceramics as the word is that they handle high rpm abuse better than the two piece or the two mm. I have the m2 ball bearing set and will be running higher than stock boost when my urges command it. I wanted something that can handle that kind of thing...mazda uses em for high boost and thus I chose to do it.

I have honestly had no probs with the apex seals in the past...it has always been o rings or side seals that destroy my bank acct. I do not want to build my motor again and will have it on the dyno this friday...in no way do I want to have a weak link in the motor and so I went with the strongest seal I could find.

my vote was for the supra...the rx spools faster and can get a little launch in my experience (back in the stock days) but when that supra spools up it goes right by....but on the track...supra = FAT. haha..plus the rx just looks better. :)

j

Supra 13.4@106.7 Isnt that like low 12's in the 1/4 mi with a 106 trap speed?? That is insanely fast for a stock Supra. am I right, or confused?

fast isn't as important as quick in the 1/4mi... it's not how fast you're going at the end that counts, it's who crosses the finish line first. slow ET and high MPH = either a bad driver or a shitty car that has lots of power... or both.

HE SAID STOCK cars... I drove the RX7 and the Supra, RX7 will take it. CT-26 turbos on the stock Supra SUCK!
RX7 will take the line, and the mid, but watch for the supra towards the end of the 1/4.....

If you have 3mm seals and can't tune for shit, stock up on rear housings. All you're doing is shifting the weak point somewhere else.