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FC Group A racecar

Old 08-24-11, 04:01 PM
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FC Group A racecar

Hello,

I've been thinking to enter racing with my RX-7 for a whole time.
I am running a '86 S4 NA gxl base model now, thats got a crushed passenger door. (Not my fault btw ... )

Point being, I am in europe and we have the FIA regulations for racing. I am mainly interested in asphalt racing, track/hillclimb etc...

After studying the rules, I might be able to run in group N or group A. (Assuming safety requirements are fullfilled)

Personally after seeing the rules, I would prefer group A as it is more liberal in terms of modification and part choices, specially in terms of engine tuning.
Group N is too restrictive, thats why they call it "lightly modified" or "production cars".
My plans were to still have a street legal car, which can be used for racing/track. Not a full all out racing car, but at least group A legal.
Safety comes first, and so the rollcage. Here it is basically street legal to have a fully professional welded rollcage with FIA certificate in your street car.


I would like to have some feedback from people who are running/ran in group A and a bit of experience with the regulations. Specially rotary-related stuff.
Those regulations, I feel are sometimes contradictory. I have the official FIA regulations on hand here for group N and A right on my desk

I see you guys are racing in NASA and SCCA events over there in the USA but we dont have such thing. Only things are group A or N racing events.

Anyways I have a few specific Qs to the pros about different topics.
I searched but the results for group A results were very limited.

I will start with one important question, (few more to come)
Group N + A requires a production car with 4 seats minimum.
So does this mean 4 seats stock and I can ditch the rear 2s for the sake of a rollcage, or do the rears need to remain functional ?

The exhaust, can I replace the funny thermal reactor with a header ?
Downstream the exhaust manifold exit, the exhaust is free [...]
Article 255 (2011) Specific Regulations for Touring Cars (Group A) - published on 06.06.2011


Help is greatly appreciated.
Steven
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Old 08-24-11, 04:30 PM
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like you say we have different rules here, as we don't run FIA, so it might help to post the rule sets. or a link to said rules.
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Old 08-24-11, 04:37 PM
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like you say we have different rules here, as we don't run FIA, so it might help to post the rule sets. or a link to said rules.
Sorry, I forget to add them. Here is the link to the FIA Group A ruleset:http://argent.fia.com/web/fia-public...03.06.2011.pdf

Steven
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Old 08-24-11, 05:42 PM
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hmm odd rule set! it would be really nice of you could find the homologation papers for the FC. its possible mazda had some different gear sets or exhaust setups or something.

the rules regarding the intake an exhaust conflict, so you should ask.

"In the case of rotary engines, and on condition that the original
dimensions of the inlet ports of the exhaust manifold are
respected, the dimensions of the ducts in the manifold are free."

i think that means if the inlet of the exhaust manifold is the same as stock, you can run anything?

"In the case of rotary engines, on condition that the original
dimensions of the intake inlet ports and of the exit of the exhaust
are respected, the dimensions of the inlet and exhaust ducts into
the engine block are free"

this means stock port, but custom intake manifold?

on the intake manifold side it says "For a normally aspirated engine, the plenum is free, but it must
remain in the engine bay." which i think might mean you could run a custom intake, but then it later say you need a stock sized throttle, so maybe not...
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Old 08-24-11, 05:54 PM
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An old Group A Toyota was in the near vicinity yesterday as a coincidence with a ***** to remove turbo....are you sure the Mazda will be eligible or is this some form of racing using those rules?

People here often get the idea, that because S1~3 ran in that category, later variants will too, to end up disappointed when they're knocked back at the homologation hurdle. Here's the list of historic ones.

http://www.fia.com/resources/documen...ogations_a.pdf
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Old 08-25-11, 06:34 AM
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Thanks for the answers.

Well as for this rule:
"In the case of rotary engines, and on condition that the original
dimensions of the inlet ports of the exhaust manifold are
respected, the dimensions of the ducts in the manifold are free."

i think that means if the inlet of the exhaust manifold is the same as stock, you can run anything?
For me too this looks like if the exhaust port inlets on the exhaust manifold are unchanged I can run a header as the ducts are "free"

The crucial point here is the exhaust port inlets. So it will be legal when I leave the size of the exhaust port inlets unchanged ?
Tuningwise I can change the exhaust port timing (inner housing side) leaving the original diameter for the exhaust port inlets .

"In the case of rotary engines, on condition that the original
dimensions of the intake inlet ports and of the exit of the exhaust
are respected, the dimensions of the inlet and exhaust ducts into
the engine block are free"
My understandment of this rule is that you can run whatever ducts to the inlet and exhaust ports based on the condition that your porting remains unchanged.
So this poses the question IF I choose to port it (Streetport/bridge) I am limited on the stock duct diameter for inlet and exhaust.
If this is true I can live very well with this rule. I have the benefits of street porting and I can use extrude honing to smoothen the duct inside walls without changing their size. As modifiying/machining/grounding/balancing stock parts is allowed with exception of further limitations seen under the respective category (engine, trans ...)

But anyway after all these rules who is gonne check/mesure if the engine ports or ducts are stock or modified once the engine is assembled/installed and ready to go ? Will the FIA scrutineer disassemble the block or what ? I dont want to build something and have it disqualified by someone because the ruleset is to vage and it can be seen either so or so.

Questions over questions ...

Thanks
Steven
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Old 08-29-11, 08:25 AM
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With so many questions, I would think that it makes sense to talk about your build with the local sanctioning bodies chief scrutineer. I know that in Europe you have regional, Country and continent bodies, so that it can be confusing. Pick the country where you are going to be racing, call them up and introduce yourself respectfully. I have built a few cars and have always found it of benefit to discuss build plans with them. They are usually open to this type of approach and can help you with their interpretations of the rules. They are going to be checking out the car, so have them clarify what they are looking for.

I have done this with NASA, CASC, ASN-FIA and SCCA and all groups were glad to assist. The guys at the SCCA were great to work with but they added 288 lbs to my other car and wanted me to make a number of changes to allow it to race. They clearly stated the rules, the class direction and the class philosophy. Same with the CASC and ASN-FIA guys. NASA just told me to show up and they will find me a place, LOL. This has worked for me and when you get the interpretations, I am certain that there are enough smart guys on this site that will help you with the work arounds.

Eric
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Old 08-29-11, 11:57 AM
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Originally Posted by 23Racer View Post
With so many questions, I would think that it makes sense to talk about your build with the local sanctioning bodies chief scrutineer. I know that in Europe you have regional, Country and continent bodies, so that it can be confusing. Pick the country where you are going to be racing, call them up and introduce yourself respectfully. I have built a few cars and have always found it of benefit to discuss build plans with them. They are usually open to this type of approach and can help you with their interpretations of the rules. They are going to be checking out the car, so have them clarify what they are looking for.
Yes, thats what I am trying. Not that easy to get someone with rotary knowledge, still phoning around.

It s a lot easyer to discuss rule interpretations with a scrutineer before doing any work. Saves time, money and nerves.

As long everything is conform there should be no problems, but with a rotary engine the chances are high that other people try to pick around and interprete rules different. The rotary would be advantageous placed in the 1000 to 1400 ccm class.


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Old 08-29-11, 02:10 PM
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Originally Posted by StevenL5975 View Post
Yes, thats what I am trying. Not that easy to get someone with rotary knowledge, still phoning around.

It s a lot easyer to discuss rule interpretations with a scrutineer before doing any work. Saves time, money and nerves.

As long everything is conform there should be no problems, but with a rotary engine the chances are high that other people try to pick around and interprete rules different. The rotary would be advantageous placed in the 1000 to 1400 ccm class.


Steven
well a header is a header, you just need to make sure that it is a header...

um you have a good point, i see nowhere where they mention a correction factor for the rotary, usually they double the 1.3, and class it that way, but i don't see that. so yeah a 13B would kick *** in the 1-1.4L class!
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Old 08-29-11, 05:25 PM
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The rules for general classment say this about the rotary engine classment:

3.2 Equivalence formula between reciprocating piston and
rotary engines (of the type covered by the NSU Wankel
patents)
The equivalent cubic capacity is equal to the volume determined
by the difference between the maximum and minimum capacities
of the combustion chamber.

Appendix J Article 252 of the FIA regulations (General rules): http://argent.fia.com/web/fia-public...E/252_2011.pdf

For me that looks like the same formula Mazda used to calculate the 1308 ccm of the 13B.
Volumetric displacement. So if thats true then the 13B would be a lucky candidate in the 1-1.4L class.

Originally Posted by j9fd3s View Post
well a header is a header, you just need to make sure that it is a header...

um you have a good point, i see nowhere where they mention a correction factor for the rotary, usually they double the 1.3, and class it that way, but i don't see that. so yeah a 13B would kick *** in the 1-1.4L class!
Thats exactly what makes me happy to still drive "that old rotary".
For beginning I will run the 13B stock as it is, maybe a new exhaust, mine is falling apart soon. The rest is going to be stock with cage and some safety equipment required.
I first need to get experience to drive on a track. I learned heel-toe, practicing it 2 years DDing, but of course the track is a different thing, but I think 2 years of heel-toeing comes handy.
I am still searching to learn new things and it makes fun. The 7 really is a fun car to drive after all.

For the engine I made a plan to build myself a race engine and everything that comes with it if the worst comes and its time to rebuild.
I need to adjust plans a little to fit Group A regulations, so some details may vary, engine budget was aimed at 10k$.

Last edited by StevenL5975; 08-29-11 at 05:27 PM.
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Old 08-30-11, 07:27 AM
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Originally Posted by StevenL5975 View Post
The rules for general classment say this about the rotary engine classment:

3.2 Equivalence formula between reciprocating piston and
rotary engines (of the type covered by the NSU Wankel
patents)
The equivalent cubic capacity is equal to the volume determined
by the difference between the maximum and minimum capacities
of the combustion chamber.

Appendix J Article 252 of the FIA regulations (General rules): http://argent.fia.com/web/fia-public...E/252_2011.pdf

For me that looks like the same formula Mazda used to calculate the 1308 ccm of the 13B.
Volumetric displacement. So if thats true then the 13B would be a lucky candidate in the 1-1.4L class.



Thats exactly what makes me happy to still drive "that old rotary".
For beginning I will run the 13B stock as it is, maybe a new exhaust, mine is falling apart soon. The rest is going to be stock with cage and some safety equipment required.
I first need to get experience to drive on a track. I learned heel-toe, practicing it 2 years DDing, but of course the track is a different thing, but I think 2 years of heel-toeing comes handy.
I am still searching to learn new things and it makes fun. The 7 really is a fun car to drive after all.

For the engine I made a plan to build myself a race engine and everything that comes with it if the worst comes and its time to rebuild.
I need to adjust plans a little to fit Group A regulations, so some details may vary, engine budget was aimed at 10k$.
I really think that you need to speak with someone in the Rules Making Commitee as I read that somewhat differently. The rotary motor has always suffered from trying to determine its displacement. In effect each chamber is 1308 cc's, but per rotor there are 3 working chambers at different points in the engine's operating cycle. Initially that meant that the 1308 cc's were multiplied by a factor of 3 which meant that the motor was actually 3924 cc's or almost a 4 litre engine! Strong negotiating and slightly different interpretations basically sawed off that the displacement was based on the 2 chambers that were actually doing anything and almost all racing series across the world adopted a x2 factor in classifying the car or as a 2616 cc engine.

This means that your car will be racing with the naturally aspirated 2600 cc cars in whatever class they run in. If you look back at all the different series from around the world, this is where the car has fallen into the mix. In North America it has always been in classes against under 3.0l litre cars. Back when the FC was released the main series was the Firestone Firehawk Series. In Firehawk it was a Sports Class car, not a Touring Class Car for up to 2.0l and not a Grand Sports Car which is for 3.0L and above. It ran against all the mid sized sports coupes like the Preludes, BMW's, Turbo 1.6L MR2's and even the SHO Ford Taurus's.

It would be an incredibly large hole or oversight in your rules if they allowed you to race it in the 1.0 to 1.4 litre classes. I expect that you will race in whatever class they put NA 2.6 Litre cars in, sorry to say.

Eric
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