On my LS1 F-Bod the exhaust manifolds were very good. Replacing them with shorty headers was not recommended because they flowed the same as Shorties and sometimes outflowed Shorties!

What is our exhaust manifold like on our Z's?

I know the shorty header prices I have seen are ridicoulous for 4 HP!!

I also read that the new Honda won't even have an exhaust manifold!

Anyway, anyone know anything about our stock one and how well it flows the exhaust compared to aftermarket shorties?

 

I can tell you from the service manual that the exhaust manifold runners are straight sequential. So I'm sure there is some power to be gained by widening them and making the runners equal length. as far as long versus short, that remains to be seen.

 

I am not a mechanic, I understand the gist of your post that the manifolds could flow better?

Everything else sounded Greek. Sorry I am not the mechanicly inclined type, wish I was , could save allot of cash.

Do they make mid or Long Tubes for our cars?
I know shorties are usually a waste of cash.

Also, is there just one or is there two manifolds?

Two Cats so I assume headers on both sides?

What brand should I watch for for headers?

I know L/T's on V8's are good for like 3 tenths or 35HP on average! Good mod.

 

Header design is pretty complex, soo to explain everything would probably lead to you losing interest in the text. Also there is no magic simple formula for determing primary tube size and length, it's complicated and you need to set a specific goal, know the cam timing and other engine characteristics. So I'm just gonna cover the basics here.

In general you want a header that has equal length primary tubes, the pipe between the exhaust port and the collector, that way the exhaust pulse on one pipe creates a vaccum on the other 2( assuming a 6 cylinder engine with 123 pair and 456 paired), if properly timed you will create a vaccum on the exhaust during the intake stroke of one of the other cylinders to help draw out "Stalled" exhaust gas and also pull in fresh air. Now the question is do you want "long" or "short" headers, the rule of thumb is short headers help in the upper RPM range while long headers help in the lower. So if you wanted to say increase low end torque you'd move a long header design. Now naturally it's not that simple, the runner size is just as important. The bigger the tube the more it flows, however if it's too big the gas loses velocity and you're not going to create a vaccum and the gas will tend to hang in the pipe. Soo if your engine was chocking and had a high redline, you could run bigger tubes, but you'd sacrifice lower RPM torque. the flip side naturally is if you never went past 5500 rpms( made up number) then you'd be better off with a smaller tube diameter.

with all that said I have no clue about the aftermarket for the VQ soo you're on your own

 

As a side note, the firing order for the cylinders is in fact 1 2 3 4 5 6.

 

So then no research is available yet about the stock exhaust manifolds compared to 50 state legal shorties?