Hey guys!

Just had my J's Racing headers arrive (after 2 and a bit months) and i was wondering about a few things.

1. Is there much difference in size from the standard headers? These have an approximately 2 inch outlet on them (50mm).

2. How big is the standard inlet at headers and outlet at muffler on exhaust on a honda fit/jazz 1.5l? Im getting a full custom exhaust on wednesday and want to know if a 50mm exhaust will improve flow? (Note: Exhaust will include hi-flow cat, resonators and muffler).

3. Will stainless make any difference to mild steel? Its $650 for mild steel custom and $950 for stainless steel of the same exhaust. Sound/heat/will i get bang for buck by spending the extra 300 or is it just looks?

Just so i know if the mm difference will be worth what ive spent on headers and a full exhaust. The stock exhaust already looks 50mm.


Thanks guys

regards

Nick


3. W

 

Stainless steel lasts longer, is more expensive, and conducts heat slower than mild steel (which is a good thing). It will not sound any different than mild steel because it is almost of the identical density. However, pay attention to wall thickness. A heavier wall thickness will damp the acoustic noise of the exhaust more than a thin wall, giving it a lower pitched sound. There are also many different kinds of stainless, you should ask exactly what kind of metal you're being quoted. Ask for the Mil Spec, AISI, ANSI, or ASTM of the metal you're getting quoted. You're likely getting quoted 101 mild steel and 304 stainless. Both are about the cheapest. Some more expensive stainless like 316L give you even better corrosion protection.

Secondly, don't expect a shop to have engineered an exhaust system for you. Exhaust tuning is a combination of fluid and acoustic dynamics that is partly lots of testing and partly science. Simply increasing or decreasing the pipe diameter may not give desired affects. Bolting on hi-flow cats, resonator, and muffler, as you wrote, to a stock system will likely give you the same result.

 

Hi thanks alot!

Not sure on specifics but had 2 cars done by these guys and they have been running for over 30 years and are a good kept secret. I was more curious as to the size of the standard exhaust to see what size difference id have. It looks 50mm stock!