Are the STD and DX exhaust manifolds diffrent?
91 Honda Civic STD

 

no

 

Yes, they are different. The DX has a manifold designed for an underbody cat like the SI. But the STD has a close-coupled cat type manifold like the HF.

 

go to http://www.homemadeturbo.com and make a set up like that with ur std. neat stuff at that site.

 

not in 1991 they didn't.

MY 1991 Civic HB STD has a DX/Si style exhaust manifold, yes it was the original!

 

I like StorminMatt thought Bone was wrong. After a little research only the 88-89 STD had the HF style manifold. The 90-91 models had the full manifold and down pipe.

So I guess the correct answer would be yes and no.

 

i know for sure the 90 std has the manifold under the car like the dx/si, so wronghand seems to have the correct info here.

 

When I had my 90 STD, It had the same exhaust manifold as the DX... My cat was under the car...

 

mines also!!!!