Mazda Rotary Club

Cars by Model Type => 3rd generation RX-7's => Topic started by: RERX7 on August 24, 2010, 01:59:49 AM

Title: 2mm or 3mm apex seal?
Post by: RERX7 on August 24, 2010, 01:59:49 AM
hi as title? when to use 2mm and when to use 3mm?? also will the carbon apex seal a lot stronger then the normal apex seal? thx guys
Title: 2mm or 3mm apex seal?
Post by: ttpower on September 08, 2010, 11:12:20 PM
use 3mm if your going to use above a bar of boost. The carbonseals are said to be stronger, do some research the apex seals vary depending on what your application is.
Title: 2mm or 3mm apex seal?
Post by: Mir on September 09, 2010, 12:29:14 AM
Chris Impey, According to my tunner is running 2mm oon his drag car and according Tim RX Motors, his drag car is pushing out 800bhp???? So where you got this information @ ttpower
 
Regards
Title: 2mm or 3mm apex seal?
Post by: johnnymolloy on September 09, 2010, 12:41:46 AM
i have heard that the 3mm tend to wear down the rotor housings not sure or certain about this so dont qoute me maybe someone with experience can say
Title: 2mm or 3mm apex seal?
Post by: ttpower on September 09, 2010, 08:21:11 AM
Quote from: Mir;715560Chris Impey, According to my tunner is running 2mm oon his drag car and according Tim RX Motors, his drag car is pushing out 800bhp???? So where you got this information @ ttpower
 
Regards


It is said to use 3mm so you can increase your boost levels. Tim might be getting that figure at a bar of boost depending on turbo and running higher octane fuel. As i said before there are many variable factors and is down to individual prefrence.
Title: 2mm or 3mm apex seal?
Post by: BlitzBoy on September 09, 2010, 10:01:50 AM
Quote from: ttpower;715572It is said to use 3mm so you can increase your boost levels. Tim might be getting that figure at a bar of boost depending on turbo and running higher octane fuel. As i said before there are many variable factors and is down to individual prefrence.

what a load of tosh dude :flamed

Tim and Chris are getting that figures well over 1.6 BAR

Dragon in there 9.1 second drag car was running stock mazda 2mm nearly hitting 2 BAR

I\'m running 2mm, James Willaday low 10 second drag car at 1.4 BAR 2mm, Robrs running 2mm low 10 second car 1.4 BAR etc etc

I dont really need to go on do I lol

people running 3mm is historical gave a little bit more knock resitance but since the advent of better tuning knowledge,ECUs, ignition, aftermarket 2mm seals, there is no need for 3mm in my eyes anymore, 2mm is better if you want a high reving rotary eg past 8.5Krpm
Title: 2mm or 3mm apex seal?
Post by: BlitzBoy on September 09, 2010, 10:05:18 AM
Quote from: ttpower;715552use 3mm if your going to use above a bar of boost. The carbonseals are said to be stronger, do some research the apex seals vary depending on what your application is.

you dont use Carbon seals on a "TURBO" rotary only NA.
different types of steel alloy and ceramics are used on turbo rotaries.




To the orginal poster use stock 2mm mazda, if you going monster bhp then (over 500bhp) then you can take a look at PTS,SCR,Atkins seals for a bit of insurance but stock mazda when tuned right will take big power.
Title: 2mm or 3mm apex seal?
Post by: ttpower on September 09, 2010, 10:37:58 AM
First of all, i didnt say 2mm are no good for high boost levels, 2mm seals are perfectly fine for extremely high boost levels. Many people sucessfully run 20+ psi on stock 2mm seals with no problems.

However, 3mm seals are much more durable and many have (1) great tuning skills and (2) the financial resources to shrug off a small tuning mistake that requires a full rebuild.
One hard ping and a 2mm seal will likely break. 3mm seals generally take much more tuning abuse (multiple, hard pings), which is oftenenough margin to back off and save the motor. Also, Pineapple Racing uses a special 2-piece 3mm seal that, when it does fail, tends not to cause subsequent damage to rotors and housings.

While getting the rotors machined out for 3mm seals and purchasing the seals themselves costs a bit more, it does not begin to compare to that of a second rebuild.
3mm seals are relatively cheap insurance.
Title: 2mm or 3mm apex seal?
Post by: BlitzBoy on September 09, 2010, 12:02:18 PM
Quote from: ttpower;715615First of all, i didnt say 2mm are no good for high boost levels, 2mm seals are perfectly fine for extremely high boost levels. Many people sucessfully run 20+ psi on stock 2mm seals with no problems.

.

No worries dude from reading you made a number of assumptions in your previous posts which you gave the impression that 2mm were no good for high boost hence my first post reply.

3mm are just as likely to break from tuning mistakes or failure of an ancillary .

I have seen some carnage of 3mm seals as well when they break in engines.

I disagree with the statement "much" more durable, there is only a slighty more strength in them, but when you get bad det they will break as well.

3mm will also wear your housings quicker.

The cost of milling out the rotors and getting them rebalanced you may as well put that money and buy the better uprated seals in the first place like SCR or PTS which bend when they hit det and dont chip and break ya housing.
Title: 2mm or 3mm apex seal?
Post by: ttpower on September 09, 2010, 01:33:22 PM
Quote from: BlitzBoy;715629No worries dude from reading you made a number of assumptions in your previous posts which you gave the impression that 2mm were no good for high boost hence my first post reply.

3mm are just as likely to break from tuning mistakes or failure of an ancillary .

No prob mate. Wasnt meant to be read that way lol :rolleyes:

I have used 3mm on my old half bridge but now using 2mm with a touch over 500bhp at 1.1bar with my apexi rx6 turbo! Spools and revs perfectly!

Facts of matter is no engine is bullet proof, an engine\'s output is dependant on vast amount of varibles inc tuning.
But it is common knowledge that 3mm are more durable then 2mm but then again can depend on what type of seals they are using. Another application for 3mm apex seals is where your rotor clearances are void and milling to 3 mill can save you from scrapping your rotors.

Like i said in my first post it all depends on the application and what you want out of your motor.
Title: 2mm or 3mm apex seal?
Post by: Mir on September 09, 2010, 08:44:28 PM
I have used 3mm on my 20b and i m convince that they are strong but i cant say that 2mm are not. As blitzboy said that, if the engine is tune right it does not matter whether the seals are 2mm or 3mm...As Gabby Skerrn (port reican-owner of the fastest RX7 6.97) says that its not about the seals it about the tunning. So if you want insurance, dont look for a seals..look for a good tuner....
 
Hoep this helps
Title: 2mm or 3mm apex seal?
Post by: RERX7 on September 12, 2010, 12:22:40 AM
thx a lot for the info guys! i will really spend time and consider which one to go for and how to tune it till the best ! thx!
Title: 2mm or 3mm apex seal?
Post by: DR SCHNITZEL on September 12, 2010, 03:33:10 AM
if your building an engine why not go 3mm. same price on pts,
Title: 2mm or 3mm apex seal?
Post by: SiH on September 12, 2010, 07:37:54 AM
Quote from: ttpower;715615First of all, i didnt say 2mm are no good for high boost levels, 2mm seals are perfectly fine for extremely high boost levels. Many people sucessfully run 20+ psi on stock 2mm seals with no problems.

However, 3mm seals are much more durable and many have (1) great tuning skills and (2) the financial resources to shrug off a small tuning mistake that requires a full rebuild.
One hard ping and a 2mm seal will likely break. 3mm seals generally take much more tuning abuse (multiple, hard pings), which is oftenenough margin to back off and save the motor. Also, Pineapple Racing uses a special 2-piece 3mm seal that, when it does fail, tends not to cause subsequent damage to rotors and housings.

While getting the rotors machined out for 3mm seals and purchasing the seals themselves costs a bit more, it does not begin to compare to that of a second rebuild.
3mm seals are relatively cheap insurance.

http://www.rotaryengineillustrated.com/upgrading-engine-seals/3mm-apex-seal-upgrade.html
:xconfused
Title: 2mm or 3mm apex seal?
Post by: Prof on September 12, 2010, 08:38:23 AM
As Blitzboy said - 2mm would have less rotational mass (I know there\'s not much in it) and smaller contact area with the housing (hence lower drag), so better for higher revving engine.  If you are going down the road of making a beast motor - then quite a few people are offering billet rotors as well - certainly worth considering.
 
And I\'d 2nd the comment about looking at the new seals which tend to bend rather than break.  It won\'t stop you having to rebuild a motor if it pops, but at least you\'ll be able to reuse most of it ;)