GT engine location for RX-7

[TrentO]

Upon reading the GT rules, the definition of a front engine, rear wheel drive vehicle is one where some spark plugs lie ahead of the front axle of the car. According to the rules you are allowed to set the engine back to have the front-most spark plugs intersect the front axle.  An RX-7 has the front-most plugs about 6" or more behind the front axle in the stock location.  So, is there a limit to the amount the engine can be set back? What about offset to the side?

Best,
-Trent

[10cc]

Trent,

Just connect the front engine mount bracket to the back of the front bumper...

[Spec Volcanic]

Upon reading the GT rules, the definition of a front engine, rear wheel drive vehicle is one where some spark plugs lie ahead of the front axle of the car. According to the rules you are allowed to set the engine back to have the front-most spark plugs intersect the front axle.  An RX-7 has the front-most plugs about 6" or more behind the front axle in the stock location.  So, is there a limit to the amount the engine can be set back? What about offset to the side?

Best,
-Trent

I have forward to your question to the tech committee

[gary]

The tech committee has discussed your question.
In this case  the requirment is to leave the engine in  the stock location.  Our rules are based on SCCA rules and in their rules the front spark plug must intersect with the  axle centerline. If we follow that rule you would be required to move yours forward.    Using the stock location will be a better choice.
Thank you for bringing up this concern, we will edit the rules as required this fall.

Gary Lohues
Tech Committee Chairman.

[JustinL]

To me the rules read that an RX-7 is not a front engine vehicle with the current definition. I think it could be argued that the RX-7 is a mid engine design.

A front engine vehicle is defined as one where the forward-most spark plug(s)
are located in a vertical plane ahead of the front axle centre line.

[zhao]

A rx7 is definitely a mid engine car though (fmr), just like the s2k, and that's right from the manufacturer's mouth.

What are the rules on a mid engine car's engine placement?

[Spec Volcanic]

The way I read the current GT rules Front Engine cars can have there engine move back until the front plug is inline with the front axle, as layouts where the Engine is already behind the front axle Front-Mid, Mid and Rear are not mentioned, they must stay in the factory location. 

My only question, is engine placement in a not production based car, it may be something that needs to be addressed in the future.

[jcm0791]

The U.S. rules used to be such that if the factory crossmember was used then the engine could be in the same location, relative to the crossmember, otherwise they were subject to the same "front spark plug inline with the front axle.  I have a vague recollection that they may have switched to a specified setback though I can't remember what it was or if it even came to fruition.

I have been reading the ST (O and U) rules lately more so than the GT rules but, as I recall, the SCCA specifies an offset from center (1 inch I think) ... More of a tolerance than a build spec.

Reading the SCCA rules is always entertaining as you can see the ones which were copied verbatim into the WCMA rule book and the ones which went through a little adventure on their way across the border.