Author Topic: Modified Category, Gas Coupe  (Read 5998 times)

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Offline Malcolm UK

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Modified Category, Gas Coupe
« on: November 26, 2006, 07:57:32 AM »
Some questions for readers who have worked with SCTA rules in the Modified Category.

I need guidance on the rules as they relate to modern vehicle unitary construction (monocoques if you prefer).

From 2C I take it that the two words "Frame" & "Chassis" are taken as one and the same.  

Please confirm that this is so, anyone?

In 5.D.3 Gas Coupe and Sedan ...
The rulebook states that "The following items shall be retained in the stock location and of the same year as the body: frame, fenders hood ... (etc) ....

Is the reference here to 'frame' to be taken to mean the vehicles 'chassis'?

Later on there is a paragraph with reference to "The following body and chassis modifications may be made: ..." but there are no chassis related items listed; so I cannot modify the chassis or frame?

As a unitary construction vehicle of welded sheet steel pressings, there is nothing that I would know of as being clearly a 'frame' or 'chassis'.  (There is a floor pan with side cills and bulkheads that supports people, which then with the inner wings to front and rear takes loading from the suspension at each end).

So in terms of SCTA rules what part or parts of a modern car with unitary construction form the 'frame' or 'chassis'?
Malcolm UK, Derby, England.

Offline hotrod_tommy

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Chassis
« Reply #1 on: November 26, 2006, 12:25:23 PM »
HI,  I see under Section 2 Car Competition Requirements
"2.C Frames/Chassis: Except where specifically forbidden by class rules, any design frame may be used. ...  subject to the approval of the Contest Board...  burden of proof (of strength in the design) lies with the entrant."
see also 3.B Roll Cages:
"... On unitized and monoque cars..."

so they have at least identified that structure as possible for some racing.
I'll bet if you define your target class, you can get a preliminary idea, then maybe send the tech drawings to the inspection guys, see what they think.  Bet they can give some useful ideas before it is built...

Hotrod_tommy...  33 coupe still in a pile, still stuck in wannabeland.
 :shock:
Tommy's2slow for racin

Offline Malcolm UK

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Re: Modified Category, Gas Coupe
« Reply #2 on: December 05, 2006, 04:40:11 PM »
Have made contact with the appropriate committee member and they are investigating the particular xar that I hope to use.

I had hoped that this 'problem' might have surfaced from US racers who would ahve given an insight into how they dealt with it. 

Will be interesting to see what a unitized construction has in the way of 'frame' or 'chassis'.
Malcolm UK, Derby, England.

Offline Sumner

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Re: Modified Category, Gas Coupe
« Reply #3 on: December 05, 2006, 04:57:37 PM »
Have made contact with the appropriate committee member and they are investigating the particular car that I hope to use.

I had hoped that this 'problem' might have surfaced from US racers who would have given an insight into how they dealt with it. 

Will be interesting to see what a unitized construction has in the way of 'frame' or 'chassis'.

Malcolm I guess I don't understand what you are trying to do, since the only allowed changes to the car are "wheel wheels may be radiused; the generator, horn and stock gas tank may be removed."


Are you concerned about installing the cage??  Putting in something like sub-frame connectors (tying the front sub frame to the rear like on a Camaro) to make the car stiffer (the cage could accomplish that)??

In your case I would say the frame/chassis is the unibody itself, except possibly front or rear sub-frames if you have them.

What do you want to do??

c ya,

Sum


Offline Malcolm UK

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Re: Modified Category, Gas Coupe
« Reply #4 on: December 06, 2006, 03:42:56 PM »
Sumner

To qualify in this class I have to make an engine change (as defined by the rules).  The motor change I have in mind is straight four to V6 so the necessity then is to relieve the stock firewall/bulkhead for various parts. 

Then, as you pointed out the rollcage is added which could bolt to the floor (as the cage rules state) but that seems to be a poor use of the steelwork. A welded in cage system, doing what you say of tieng everything together fron to rear, would be the goal. 

The suspension needs to be better located - so brackets for A-arms need to be added, shock absorber mounts repositioned and so on.  Can these be cut into the unibody interior metal work?  Could the cage penetrate firewalls and other interior metal and then be used for attachmnet points for these mounting points?

The exhaust system will need to be run above the floor pan if the ride height is to be low(ered) enough.

Perhaps I am looking at fitting a car that is inappropriate into this class ...... but the next step is full on competition coupe rules - which I mostly understand, but that design is separate chassis, fake body,  etc ......

And the car is .... well it might not have been a surprise anyway ......... the classis Austin/Morris mini cooper with front wheel drive.
Malcolm UK, Derby, England.

Offline Sumner

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Re: Modified Category, Gas Coupe
« Reply #5 on: December 06, 2006, 04:54:38 PM »
......................................The suspension needs to be better located - so brackets for A-arms need to be added, shock absorber mounts repositioned and so on.  Can these be cut into the unibody interior metal work?  Could the cage penetrate firewalls and other interior metal and then be used for attachment points for these mounting points?......................

I can see where you are trying to go with the cage and I guess you are just going to have to get some kind of ruling on it with the chair in that class.  Let us know what you find out or maybe there will be comments here.  One thing is it says "The following items shall be retained in the stock location and of the same year as the body: frame, fenders......".   In your case the unibody is the frame and you are leaving it in its original position, so I wonder if the cage extensions that could act as suspension supports would be legal, but don't feel so as that is not listed in the "permitted" items.

I'm sure you read the part about not changing a front wheel drive to a rear wheel drive.

Looks to me the class is to let someone run a production car with a slight modification to it like a motor change, quick change, or non-stock supercharger and where you are trying to go is more in comp coupe territory as you mentioned.

Driving back from Missouri to Utah I noticed a couple of the new mini-coopers and though they would make a pretty good basis for a comp coupe car.  The front isn't aero, but you throw that part of the car away anyway.

So move up to comp coupe and go for it :-D,

Sum

Offline Dynoroom

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Re: Modified Category, Gas Coupe
« Reply #6 on: December 06, 2006, 06:53:40 PM »
Some questions for readers who have worked with SCTA rules in the Modified Category.

I need guidance on the rules as they relate to modern vehicle unitary construction (monocoques if you prefer).

Is the reference here to 'frame' to be taken to mean the vehicles 'chassis'?

Later on there is a paragraph with reference to "The following body and chassis modifications may be made: ..." but there are no chassis related items listed; so I cannot modify the chassis or frame?

As a unitary construction vehicle of welded sheet steel pressings, there is nothing that I would know of as being clearly a 'frame' or 'chassis'.  (There is a floor pan with side cills and bulkheads that supports people, which then with the inner wings to front and rear takes loading from the suspension at each end).

So in terms of SCTA rules what part or parts of a modern car with unitary construction form the 'frame' or 'chassis'?

Malcolm, did you know GM's Camero, & Firebird are unit construction? Some currently hold records in the Production & Gas/Fuel Coupe classes. The rule book can be troublesome sometimes (does anyone really know how wide a '27 T is) but if you look at the cars in competition and the records it can help you draw some conclusions. BUT when ever in doubt go to the chairman of the respective class for clarification. Their names are in the rule book.
Michael LeFevers
Kugel and LeFevers Pontiac Firebird

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dwarner

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Re: Modified Category, Gas Coupe
« Reply #7 on: December 06, 2006, 10:03:39 PM »
Russ Eyres

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Offline jimmy six

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Re: Modified Category, Gas Coupe
« Reply #8 on: December 07, 2006, 11:02:18 AM »
With the advent of unibody cars for years I do not see a problem of how are rules are written. There is no rule stating the "stock" firewall must be retained. Long inline engines have been fit into Camaro type vehicles and run in Gas Coupe with new firewalls as long as there was no set back.

Forward bars have been added to cage structures thru the firewall to the front of the "frame" for stiffness. The front suspension of those cars have installed 40's style straight axles and springs for sability at high speeds. I cannot find where factory inner fender panel must remain stock. Some are however built into the unibody structure for strength. I would alter these for clearance but not remove them if it were me.

Lately we have seen Honda Civic type vehicles with engine swaps to larger displacements and physical size not factory to the vehicle. I believe these would meet the Gas Coupe rules if all other rules for the class were followed. The use of a V-6 instead of a inline 4 should not be a problem as long as all the other rules are met. IE: radiator, open grille, no setback, etc.

If I am wrong here someone else please reply.......Good Luck

First GMC 6 powered Fuel roadster over 200, with 2 red hats. Pit crew for Patrick Tone's Super Stock #49 Camaro

Offline Sumner

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Re: Modified Category, Gas Coupe
« Reply #9 on: December 07, 2006, 11:48:44 AM »
.................... The front suspension of those cars have installed 40's style straight axles and springs for sability at high speeds.........

....Lately we have seen Honda Civic type vehicles with engine swaps to larger displacements and physical size not factory to the vehicle. I believe these would meet the Gas Coupe rules if all other rules for the class were followed. The use of a V-6 instead of a inline 4 should not be a problem as long as all the other rules are met. IE: radiator, open grille, no setback, etc.

If I am wrong here someone else please reply.......Good Luck

On the straight axle part, did those cars retain the original sub-frame and then strip the a-arms/coils/shocks and replace those under the original frame?

I don't know what size the V-6 is compared to the original motor, but since it is frontwheel drive I can see a larger motor in there maybe causing major modification to the front inner unibody, which could be considered the frame, especially considering this is a frontwheel drive car.

So I had a reply, but I don't think it said much :-(,

Sum

Offline jimmy six

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Re: Modified Category, Gas Coupe
« Reply #10 on: December 07, 2006, 01:36:24 PM »
Fist question. Yes. Stock subframe is still there with bars attached to the main roll gage going to the front of it. Mark Johnson built the car and used multiple engines. It now has a GMC in it and is run by Harris and Wester.

I do not know which V-6 the person is talking about or what vehicle but a V-6 is "usually" shorter than an inline 4. (3 cyl to 4) Length may or may not be a problem.  Width may be. That's why I said if the inner fender panels need to be altered for a portion of the engine I would not see that as an frame change. The firewall appears to be the biggest thing and maybe the cross steering.

If it were me I would take a lot of pictures for my log book with and without the original engine. Then showing what portions I cut out. Then showing my new pieces welded in. I would in no way remove the entire inner panner if it was a structural part of the car...This will take many times of trying to place the wanted engine in the chassis.(time consuming). If I found this would not be possible without total removal I would find another car.

You would one hell of a time putting a KB cross wise in a Honda Civic, so don't try. I have seen a Big block Chevrolet in a Chevette so anything is possible
First GMC 6 powered Fuel roadster over 200, with 2 red hats. Pit crew for Patrick Tone's Super Stock #49 Camaro

Offline Sumner

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Re: Modified Category, Gas Coupe
« Reply #11 on: December 07, 2006, 02:24:54 PM »
...............I do not know which V-6 the person is talking about or what vehicle but a V-6 is "usually" shorter than an inline 4. (3 cyl to 4) Length may or may not be a problem....

Good point I didn't think about that. :-).

....................You would one hell of a time putting a KB cross wise in a Honda Civic, so don't try. I have seen a Big block Chevrolet in a Chevette so anything is possible

I'm confused  :?  you say don't try and put a KB in the Honda, then you say "anything is possible :wink:.

I use to see a really nice/great workmanship VW bug with a hemi in it at some of the car shows in the southwest, but can't find a digital picture of it.  The guy drag raced it for a little while until his wife put an end to that :-D.  That would probably qualify as an engine change 8-).

I think Malcolm should hire you as his consultant.  You gave him some good directions to go in.

c ya,

Sum

Offline jimmy six

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Re: Modified Category, Gas Coupe
« Reply #12 on: December 08, 2006, 01:19:38 PM »
Sum: I'm sure the VW had the engine in the back seat or in front . I couldn't concieve of a person attaching in the stock location; that's why I said what I did about the KB in a Civic...Remember this all started trying to be a Gas Coupe. Altereds are completely different when built to the specs of the rules and not just taking a Prod/Gas Coupe and putting some tape over the grille.. :-D
First GMC 6 powered Fuel roadster over 200, with 2 red hats. Pit crew for Patrick Tone's Super Stock #49 Camaro