Exhaust advice

[FancyFinnegan]

The exhaust on my 510 is fubar'd! Have the stock L16 with headers...but looks like the previous owner bottomed it out, thrashing the header up and bending everything front to back. The L16 is on its last leg, but I want to get the exhaust fixed so I can rod it around for the rest of the summer...with plans of doing a swap over the winter. Still on the fence of doing a rebuilt L18 or finding a ka24de. With that in mind...need to dump some money into the exhaust now, but would like to plan for the future.

 

So my questions are;

 

Headers on a L16/L18 will bolt up the same to the exhaust all the same right?

 

In the meantime, If I found a cheap stock manifold to replace the broken header, is there a big difference in how its bolts up?

 

Granted I did opt for the ka24de, how easy or how much do you have to modify it to use with the existing L16/L18 exhaust, or is it an entirely different setup?

 

L18 Size vs ka size? I read 2.25" maybe the max you want to go? I don't want to get crazy with it, just don't want to restrict it.

 

Thanks for any advice as always!

[metalmonkey47]

On my L20B I'm running 2.25 exhaust size out of a shorty header.

 

I've got a 2.5'' Flowmaster Super 10 on it now, and it sounds great but it's LOUD. Between the stock manifold and the header, I noticed an overall decrease in my top end, but I got a little more bottom end and mid range (strange, I know) and didn't notice anything when I went from my stock 1 7/8'' to 2.25''.

 

 

2.25 seems like a good idea since there's a possibility you'll get a KA in there soon, since that's probably optimal size for a mildly stock KADE anyways.

[datzenmike]

L16/18s use the same exhaust manifold so a header that fits one will fit the other.

 

A header has a single round pipe outlet (usually horizontal so it can mate to the exhaust pipe, although 'shorty' headers are still pointing downward and may have an elbow supplied with them) while the L16/18 manifold has two smaller pipes pointing downward. The stock exhaust pipe has the matching two down pipes that quickly join together into one pipe then bend level and go back to the resonator.

[Boaty]

I ran 2" on my L20B, was mildly hot-rodded out.

 

2.25" is usually the most common, but remember the bigger the pipe, the louder your exhaust.

 

On mine I ran a 2.25" ID resonator to kill noise - and it did, wonderfully. But it did kind of stop down some power up on top.

 

Personally I can't stand loud exhaust anymore. I grew up, I'm not 17 anymore. I'd rather it be quieter than louder. I liked my set up, it was about perfect for me. 2", 2.25" ID resonator mid-pipe, and magnaflow muffler at the rear.

[FancyFinnegan]

Yeah I'm with you Boaty, I meant to mention I didn't want anything too loud...prefer the silent sleeper! Thanks for the info guys.

[datzenmike]

Get a 2-2 1/4" pipe and the largest length muffler you can find that fits that size inlet. Optional is a full length tailpipe to the back. done

 

If (I have no idea, just a guess) your stock pipe width is 1 3/4" it has a cross sectional area of 2.4 square inches. If you increase the diameter just 3/4" more (2 1/2") you double the area to 4.90 square inches. That's like a 200+ hp L20B!! Or 3 L16s!!! Over kill. A 30% increase would be plenty. Lets say Nissan used that size as a compromise and it would run 'better' with a 10% increase but this works well, is cheaper and quieter so they use the slightly smaller pipe. If you substitute a 2" pipe the cross sectional area is almost exactly 30% larger. A 2 1/4" pipe is 65% larger. A 2 1/2" pipe is 104% larger. Largest isn't always better... a very small increase in diameter makes a huge increase in cross sectional area. Doubling the diameter increases the area by 4 times!!!

[Boaty]

I like being able to hear the engine over exhaust... I think I may stick with 2" exhaust even with my KA24DE. Just have the bends made up with 2.25" maybe. Haven't got that far yet, that's the last step.

[bonvo]

im running 2.25 on my l 20b it flows well if you run the l16 with a header have the system flanged at the fire wall that way they system is still in place but if you decide to go ka you just need to make a section from the manifold to the flange

[Uber Deaf One]

I like being able to hear the engine over exhaust... I think I may stick with 2" exhaust even with my KA24DE. Just have the bends made up with 2.25" maybe. Haven't got that far yet, that's the last step.

 

Wow. No. Don't do that lol. I have a 2.5" exhaust but the bends weren't done with a mandrel bender... so a lot of my exhaust piping is closer to 2" Can definitely hear the engine over the exhaust... the exhaust note is actually almost too quiet for me lol

[Boaty]

Don't do what? I only do mandrel exhaust.. so 2" all the way back with 2.25" bends should even it out considerably.

 

A buddy ran his VG30 through a 2" exhaust. SR20VE through a 2" exhaust as we speak.

[Uber Deaf One]

I read that as 2" all the way back lol

[rusty12ver]

Boaty, what resonator are you running? Looking to add one to quiet my exhaust way down.

[Spades]

some good info in here:

 

http://community.ratsun.net/topic/26004-exhaust-thread/