H4 Engine preparation

[araychel]

I am wondering if the JDM D15B VTEC engine can be run in H4 in a coupe. Or can the VTEC D15B head be used on the D16Z6 block? Am I correct in assuming that the only real modifications that can be made are slight port matching, slight head milling, intake and exhaust? Help from anyone with experience in this class is appreciated.

[PSUCRX]

H4 is pretty much a spec class. Engine modification is limited. So to answer your question, no, unfortunately that motor would not be legal. Depending on what actual car you are running, will determine what motor you can use. For example, a Civic CX can use a D16Z6/Y8 and still be H4 legal. However, that same motor, if put in an 88-91 EF Chassis will not be.

[civicrr]

Sorry. The answer to both question is no.

 

H2-H5 is only allowed to run USDM model correct engines. In other words, you have to use the engine (& tranny) that was supposed to come with that trim level/model as offered in the USA. There also isn't any provision for head swaps or component mixing in the regular classes.

 

eg You can run a D16Z6 engine in the 5th generation Civic coupe, sedan or 'hatch because the car came with that engine. The coupe & sedan were offered here (USDM) with the D16Z6 in the EX trim. The 'hatch used the engine in the Si.

 

From Honda Challeng Rule Book

7. Allowed Modifications- H1- H5

OEM, stock and/or factory refers to the same model, domestic market and generation as the listed vehicle. When allowed modifications permit other models, domestic markets and/or generations, it will be specified as

part of the allowed modification.

 

Check the rulebook which is a lot easier to understand/read clearly for 2005. Following is the link for the NASA rules page. Follow links for Honda Challenge & NASA CCR.

http://www.nasaproracing.com/rules.html

[civicrr]

For example, a Civic CX can use a D16Z6/Y8 and still be H4 legal. However, that same motor, if put in an 88-91 EF Chassis will not be.

 

Careful there. You must use the correct engine for the model generation. Yes the you could use the D16Z6 in a 5th gen (92-95) Civic CX/DX/VX- if you use the 'chassis swap' rule.

 

You couldn't use the D16Y8 in the 5th gen. because it belongs in the 6th gen car.

 

If you used a 6th gen car and it was offered for sale that way, then it could be a legal chassis swap. For example, the D16Y8 was never offered in the 'hatch. It was only offered in the coupe & sedan (EX trim). Therefore, a D16Y8 'hatch would be considered an illegal 'chassis swap' & a H1 car.