Exhaust recommendations..

[Stoffregen Motorsports]

But what if the engine wants to breathe 36% more? Or even more than that.?

 

An engine is an air pump. The more air it can get in and out, the more power it makes.

[Tolkmod]

got a quote for $500 for the complete job, with bout 1/4" bigger pipes, a new muffler, smaller muffler, (sorry don't know what else to call it, but a smaller secondary muffler) and new pipes up to the manifold. As well as a pretty new tip lol  

 

Should I go for a catalytic converter as well? or leave it off?

[thisismatt]

Cat will add another...$300+ to the price?  You could, if emissions concern you.  Smaller muffler...resonator?

[Tolkmod]

Cat will add another...$300+ to the price?  You could, if emissions concern you.  Smaller muffler...resonator?

 

Not to concerned with emissions in general, i mean this is a 1974 car so .... yeah, just want to get rid of the stink lol 

Right now it's coming out from under the sides and I can smell it bad if i have my window down. 

 

Probably just fixing the holes in the system will help with that, but i figure if I'm gonna spend $500, might as well do it right.

[Stoffregen Motorsports]

If it didn't come with a cat, I would not add one.

 

$500 is a pretty good price for a custom exhaust.

[Tolkmod]

If it didn't come with a cat, I would not add one.

 

$500 is a pretty good price for a custom exhaust.

 

Okay, and i wasn't sure if that was a good price or not.  I do know that these guys come highly recommended and do really good work.  So in the end it'll be worth it.

[datzenmike]

Post #26...

 

How is it ever going to need to breath 36% more air? Poster only mentions needing a replacement pipe. Not that his engine is modified and certainly not that he has a turbo. If stock stay close to stock pipe size. If planning modest performance increase don't over do the pipe size.

 

 

A 1/4" pipe increase will cover anything you could possibly modify an engine to, except maybe a turbo. If stock is 1 1/2"then 1 3/4" is 36% larger and all you could possibly need. You will get far more from a lower restriction 'muffler' than going to a larger pipe. Keep restriction (resistance to flow) to a minimum and pipe size as small as possible to keep the gas speed high... but not so small that it becomes restrictive. A small increase in pipe diameter makes a huge increase in the amount of gas that can flow through it.

[Stoffregen Motorsports]

If the pipe size was too small from the factory, that's when you'd need more.

 

The stock, blueprinted L16's that we used to build for SCCA ITC 510's (stock class with only Weber DGV and any exhaust) made the most power and torque with a 2.5" exhaust and a Nissan Motorsports header with a modified collector. What's a stock 510 exhaust pipe diameter? 1.75?

 

I try not to apply too much logic to engine tuning. If an engine wants something, give it to 'em.

[Lockleaf]

While I won't argue that larger exhaust can build more power, in my experience that power becomes much peakier. I'm in the middle of what you two discuss. I believe there is power loss in exchange for noise/fitment/cost when a company chooses exhaust sizing. But I also believe that most of these small fours get better power under the curve, and a better shape of curve with a midsize pipe. My experience, plus my reading of empirical data (dyno sheets etc), puts a great middle point at 1/4-3/8 of an inch pipe size bump on small motors. Satisfies butt dyno, shows real improvement on real dyno, and puts power in middle where a street car is actually driven. This is not specifically Datsuns, but just low displacement 4 cyls in general.

[datzenmike]

If the pipe size was too small from the factory, that's when you'd need more.

 

The stock, blueprinted L16's that we used to build for SCCA ITC 510's (stock class with only Weber DGV and any exhaust) made the most power and torque with a 2.5" exhaust and a Nissan Motorsports header with a modified collector. What's a stock 510 exhaust pipe diameter? 1.75?

 

I try not to apply too much logic to engine tuning. If an engine wants something, give it to 'em.

 

Yes if too small but as shown, a very small increase makes a very big difference. The factory would have sized the pipe for average driving not racing and being a touch small would have zero affect. 

 

Did they run mufflers that were stock??? for SCCA ITC 510's (stock class with only Weber DGV and any exhaust) because if open pipe, this is where the increase came from.

[Stoffregen Motorsports]

There are decibel limits so a muffler is required.

 

There's no one right answer for all the arguments for and against or for a specific size or combination, but to say that large exhausts are pointless is not a very well researched statement.

 

The argument that factory engineers are smart guys and would not design it a certain way unless...also is a very benign statement.

[Anabolic620]

The older you are the quieter you like it. Yes I'm old but I like to hear my car working (I don't mean the engine) Too much and you can't hear the bad wheel bearing until the rotor welds to the spindle, The differential locks up the rear wheels, the U joint flies apart, transmission runs dry etc...

This made me laugh but it's true. Too loud and you miss key things with the car that it's trying to tell you. Even being able to hear the click click click of a nail in a tire rotating as you drive is a big deal. Respect.

[cruznude]

I don't know, but I am an older man in early 50's and I love to hear the sound of my motor, After putting the weber in, I took it down to have an whole new 2" exhaust ran w/resonator and new muffler and chrome tip. Done in an hour and a half and cost me roughly 225.00 and all is new and sounds great.

[Buzzbomb]

I don't know, but I am an older man in early 50's and I love to hear the sound of my motor, After putting the weber in, I took it down to have an whole new 2" exhaust ran w/resonator and new muffler and chrome tip. Done in an hour and a half and cost me roughly 225.00 and all is new and sounds great.

 

TBH, that is what I would expect for a custom exhaust system for a SINGLE pipe setup. I think $500 is too much, but that's IMHO. People get full duals on a V8 car for less than $400 with the shop bending the pipes. Note that is "crimping" the pipe for bends, not mandrel bending.

[Stoffregen Motorsports]

This car is in SoCal. $500 for a full custom exhaust is about right for LA.