I had my friend who works on Hondas install a 4-2-1 header on my D16A CRX Si. But now when i give it gas i hear a HISSSSS whenever the car starts to move. Also. i have knowtest a SUGNIFICANT decrese in acceleration as well as less tone comming from the exhaust tip. Im just wondering if anyone knows whats going on or what to do

 

A header definitely changes the tone of the exhaust due to the increased air flow over the cast OEM manifold. Recheck all of the bolts/nuts to make sure they are tight. You also need to check around the gasket areas (before and after the cat) to see if any air is leaking out.

 

But would that cause acceleration to be lost? It feels like the car is slagging when i give it juice and it doesnt have the same kick as before

 

Sounds strange that it would make the car feel slower, it wouls have to be a big leak to make it feel really slower, i know it sounds stupid but i'd take it off again and check thers nothing blocking the exhaust like packaging etc, it could even be a bit of old gasket??? i know its unlikely but its worth a try!!
good luck!

 

Well i just checked, and i guess 2 out of the 9 studs in the Cylinder head broke. Would this be causing the problem? Im going to take it in to get the studs exstracted and new ones installed. But would exhaust be escaping from the sides of the header if its missing 2 studs?

 

Yes it is very likely its leaking from ther if they were already broke wen you went to take them out, but if you broke them wen trying to remove it then no probs not. Easiest way to tell, is by looking as the cylinder head around the header, if its been leaking for long enough it will be black around ther wer the escaping exhaust gases will be hittting it. However, even if they wer leaking it would make a hissing sound but it would'nt slow the car down much, it'd be barely noticable (as i said it would have 2 be a major leak)
While its off, i'd just check the whole system (header,cat/de-cat,centre piece and back box) and make sure there are no baffles, gaskets or packaging blocking it. If its not that then it might just be the header or exhaust or even the header/exhaust set up. What exhaust and header do you have??

 

I bought a set of 4-2-1 DC Ceramic Headers. I mean they are a perfect fit on the cylinder head, but the downpipe to cat conection, the gasket for the downpipe creates alot of space between the two. i bolted them down tight though (it was a bitch and half BELIEVE me) and the leak doesnt seem to be comming from there at all.

 

I've just ordered a DC ceramic 4-1 header for mine, a hope i dont have the same problems! If your sure its not leaking by the downpipe to cat then it must be blocked somewere, either that or you may have a problem with something else on da car, have you checked plugs and leads, dizzy etc?

 

is it possible that the header and cat warped together a certain way so now there is a leak? i'd re-tighten the bolts and make sure you have a gasket in there. I know they say not to double up but if you have to then do it.

 

if u are retightening everything try using High Heat silicone on everything too.