25 replies to this topic

[Johnny D]

It's being checked at the Runoffs.

 

Can we get a little clarity on why and what's in the rules ??

 

J~

[Keith Novak]

1.8L cars must use an air restrictor plate. The restrictor plate must be placed between the throttle body and plenum. All intake air must pass through the restrictor plate. Restrictor plates must be the proper size as listed in the specification table, must be from Mazdaspeed Motorsports Development or from SCCA Enterprises, and must not be modified.

 

As someone who writes requirements professionally, the way the rule is written not only are gaskets not required, they are not allowed as the RP must be between the throttle body and plenum, not sandwiched between gaskets...for what that's worth.  Lots of rules are not well written so they mean what they're meant to mean and not what they say I guess.

[FTodaro]

I would be pitching a fit if I was penalized based on no or only one gasket. The gasket has absolutely  no effect on performance or function. 

[Parity]

I would be pitching a fit if I was penalized based on no or only one gasket. The gasket has absolutely  no effect on performance or function. 

 

Regardless of effect, I would be pitching a fit because it's not in the rules.

[Tom Sager]

1.8L cars must use an air restrictor plate. The restrictor plate must be placed between the throttle body and plenum. All intake air must pass through the restrictor plate. Restrictor plates must be the proper size as listed in the specification table, must be from Mazdaspeed Motorsports Development or from SCCA Enterprises, and must not be modified.

 

As someone who writes requirements professionally, the way the rule is written not only are gaskets not required, they are not allowed as the RP must be between the throttle body and plenum, not sandwiched between gaskets...for what that's worth.  Lots of rules are not well written so they mean what they're meant to mean and not what they say I guess.

Well said.  I for one feel the rule is fine as written.  See no need for gaskets unless there is a cheat being done in there somehow.  

[Ron Alan]

Looks like the SMAC has another clarification debate! The car came with one gasket...not sure what debate really unless no gasket needs to be clarified. If in fact 2 gaskets are required...how did all who had restrictors checked at runoffs  know this? Had 2 different cars with restrictors checked no less than 20 times in the past few years...with only 1 gasket or none. At Majors and regionals. Never an issue. If in fact there is some sort of a memo out there from National SCCA to all regions...it isnt being followed or even discussed?

[RWP80000]

It appears they are using the "All intake air must pass through the restrictor plate." sentence as the basis for their double gasket requirement interpretation.  

 

The rule is silent on the retention requirement for the original gasket i.e not saying one way or the other as to your being able to delete it therefore leading most to assume you must retain it, (while in practice many don't).

 

There is no stated requirement in the rule for the use of the additional second gasket.  

 

It is just as valid an assumption that the thin aluminum restrictor plate serves the same purpose as the original gasket making the practice of deleting the original gasket as reasonable as adding a second gasket.  

 

It is being done both ways in the field and I think both are valid interpretation of the rule as written.  

[mhiggins10]

It appears they are using the "All intake air must pass through the restrictor plate." sentence as the basis for their double gasket requirement interpretation.  

 

The rule is silent on the retention requirement for the original gasket i.e not saying one way or the other as to your being able to delete it therefore leading most to assume you must retain it, (while in practice many don't).

 

There is no stated requirement in the rule for the use of the additional second gasket.  

 

It is just as valid an assumption that the thin aluminum restrictor plate serves the same purpose as the original gasket making the practice of deleting the original gasket as reasonable as adding a second gasket.  

 

It is being done both ways in the field and I think both are valid interpretation of the rule as written.  

 

What does the FSM say about installing assembling that subassembly?  Does it specify that a gasket is added?  If so, where?

 

I do definitely agree that having 2 seems silly- especially if there was only one on the car.  

 

Perhaps folks were using warped plates/TBs that allow additional air through?  (i.e. the gasket was being installed on the tube/plate side and not the plate/TB side, or being skipped entirely)?

[Johnny D]

This is a good debate but thinking about it last night and what was said...

 

Was it.... that they didn't have the correct tech guy watching him take off the RP or this gasket story?

J~

[Steve Scheifler]

"Between" requirement is satisfied with or without gaskets (and anything else for that matter). It does not say "immediately between" or in contact with. But otherwise I agree that there seems to be no basis for requiring a gasket, especially since they are free/open and you could certainly consider the plate to be one.

[Rob Burgoon]

I showed up to my first NASA race with two gaskets and was admonished to remove them and keep them off.  Gave me a chuckle when the news broke.

 

The rule is vague but I don't think you can bust someone for lack of gaskets.  If anything, with the rules as written I'd argue that running 1 gasket would be more correct than running 2. (if it doesn't say you can, you can't delete a gasket)

[Caveman-kwebb99]

my current understanding is this... tech decided two gaskets are necessary, then they decided only one is necessary and now it is back to if the car passes the stall test its all good.  

 

That is second hand knowledge so don't take this to the bank just yet.

[Johnny D]

J~

[Bench Racer]

Another of those internet arguments. The FSM shows a gasket and recommends replacing with new gasket when removing/replacing the throttle body. We all (many of us) understand why the gasket is placed between the throttle body and intake manifold. SEALING.......... Someone brought up stall test, exactly, so that no air is sneaking by the sealing gasket or any other place after the restrictor plate. Side note, IIRC for cars with a single inlet restrictor (not restrictor plate)  the stall test is placing a sphere in the SIR and the engine must stall within ???seconds. No stall, go looking how air is entering the intake system after the SIR. I get/understand why two gaskets are required. Just as no gaskets can be defeated and allow air to enter after the restrictor plate, two gaskets can be defeated and allow air to enter after the restrictor plate, BUT, no air will enter after the restrictor plate with a gasket after the restrictor plate if the gasket is doing it's job and SEALING. < This being when we are talking about only restrictor plate gaskets.

 

Lets not talk about a restrictor plate being a gasket, it's no more a gasket than the throttle body is a gasket.

[Johnny D]

Gasket Material
Fills the space between two objects, generally to prevent leakage between the two objects while under compression. Gasket material saves money by allowing less precise mating surfaces on machine parts which can use gasket material to fill irregularities. Gaskets are commonly produced by cutting from sheet gasket materials, such as gasket paper (beater addition), Non-asbestos, Rubber, EPDM, Nitrile, Buna, Neoprene, Flexible Graphite, Grafoil, Aflas, Kalrez, Viton, Silicone, Metal, Mica, Felt or a plastic polymer such as PTFE, Peek, Urethane, or Ethylene Propylene (EP). In the past, the gasket material selected for specific applications may contain have contained asbestos.
Today's sealing products manufacturer's in the United States no longer produce or offer any asbestos containing products. Gasket materials containing asbestos have been claimed to have caused Asbestosis. Of course it would take the grinding of gasket material to release the fibers and then the breathing in of those fibers....possible but in the real world this would be rare. Wetting or oiling a gasket before grinding for removal greatly reduces any risk (not grinding is even better). Asbestos gasket material is still used in most of the rest of the world and is a very effective low cost material.

It is usually desirable that the gasket be made from a material that is compressible such that it tightly fills the space it is designed for, including any slight irregularities. The most common misconception when selecting a gasket materials thickness is to choose a gasket material that is too thick. The thicker the material the more likely the material being contained can weep through the pores of the gasket material itself. This is a greater issue with some materials than others. A rule of thumb is to have the material thick enough to compensate for any surface face irregularities and to permit some compression. The required compression for your gasket material will depend many factors including:

1)Surface area

2)Pressure being sealed

3)Size of bolts (assuming bolts are being used)

4)Number of bolts

5)Condition of the bolts

6)Lubrication on the bolts

All must be considered when determining torque. Torque data must be determined using all of the above and should be provided by an engineer. In most cases unless your gasket is a standard ANSI or API flange using Ring or Full Face gaskets torque data will be difficult to come by (due to staffing and the fear of law suits). In most cases the old tighten it tight enough to stop any leaks but not too tight as to completely crush the gasket is generally accepted.
http://gasketing.net/

Gasket materials
Over compression removes the ability to recover. This is also true of expanded PTFE (Teflon ®), once over compressed it will have no recovery and therefore will not longer adapt to maintain a seal. The common strategy of "The more compressive load exerted on the gasket, the longer it will last" is generally true of elastomeric materials since elastomers (rubbers) are not compressible but deflect compression. Many materials such as non-asbestos compressed gasket materials and beater addition (ie; Armstrong) materials contain elastomers in the mix of material they are produced from, making them difficult to over compress.

One of the more desirable properties of an effective gasket material in industrial applications is the ability to withstand high compressive loads. Most industrial gasket applications involve bolts exerting compression well into the 14 MPa (2000 psi) range or higher. This is why Non-asbestos gasket materials are so widely used in industrial gasket material applications.

[Bench Racer]

J, a starter rule within the SCCA, understand how to find the GCR glossary, second rule, read the glossary for specific word in question.

 

SCCA GCR Glossary definition of gasket.

 

"Gasket - A sealing component of unspecified composition which is intended to prevent the leakage of a fluid (air, water, oil, etc.) at the interface between two demountable assemblies."

 

Third rule, skip all the other definitions of the word rule. ​
 

[Johnny D]

I like the bottom line approach that the stewards finally arrived at...

 

If it doesn't leak (passes the leak/stall test) it passes.

J~

[Keith Novak]

Another of those internet arguments. The FSM shows a gasket and recommends replacing with new gasket when removing/replacing the throttle body. We all (many of us) understand why the gasket is placed between the throttle body and intake manifold. SEALING.......... Someone brought up stall test, exactly, so that no air is sneaking by the sealing gasket or any other place after the restrictor plate. Side note, IIRC for cars with a single inlet restrictor (not restrictor plate)  the stall test is placing a sphere in the SIR and the engine must stall within ???seconds. No stall, go looking how air is entering the intake system after the SIR. I get/understand why two gaskets are required. Just as no gaskets can be defeated and allow air to enter after the restrictor plate, two gaskets can be defeated and allow air to enter after the restrictor plate, BUT, no air will enter after the restrictor plate with a gasket after the restrictor plate if the gasket is doing it's job and SEALING. < This being when we are talking about only restrictor plate gaskets.

 

Lets not talk about a restrictor plate being a gasket, it's no more a gasket than the throttle body is a gasket.

The FSM does not show two gaskets.

The rules do not specify adding a 2nd gasket. (If it doesn't say you can...)

The rule does not specify where the gasket would be placed, fore or aft of the RP if a gasket is required. (No way to ensure compliance even if one gasket is kept since the relative location of the RP is not specified)

 

The use of the following non-standard replacement parts are permitted provided the use does not result in any unauthorized modification of any other component.

 

B.  Gaskets and seals, except those specified in the above rules.

 

The RP fits that definition.  Want a better rule?  Write a letter.

[Bench Racer]

I like the bottom line approach that the stewards finally arrived at...

 

If it doesn't leak (passes the leak/stall test) it passes.

J~

I don't disagree. This ^  sealing decision gets the current job done with the current rule or no current rule without pi$$ing off the masses at the runoffs. Bets on a new two gasket rule and a restrictor plate glossary definition after the Runoffs.

[Johnny D]

Yea, they'll write it. It will get misinterpreted to get an advantage, a leak, perfect.

 

"I have the gaskets and RP, not my fault it leaks !! "

 

Saying it can't leak is just too much work.

J~