Exhaust research

[5&dime720]

What mufflers are you folks running with your KA24's? Thank you for your replies!

[Cuts metal like mad]

for a ka24 I probably wouldn't go bigger than 2.5" but more likely 2.25"... at least N/A

[5&dime720]

What kind of muffler?

[racerx]

Magnaflow or dynamax, deep turbo muffler sound, quiet at idle then at 3K rpm, sounds very good...stay away from flowmasters or cherry bombs

[5&dime720]

Rex, Speed here. Pops says hi! :D :P

 

Hey, that's what I was looking to hear! Does it have good back pressure? Not too restrictive?

[banzai510(hainz)]

those turbo mufflers work for V8s so I think it can handle a 4cyl

 

cherrybomb 2 from JC witney 20$

Thrush turbos 20-40$

Dynomax Turbos (superturbo) 45-50$

Dynomax Ultraflow stainless 110-120$

 

all quiet

[nismopu]

magnaflow for the win!

[racerx]

magnaflows are about $60 and stainless is more..

 

2.25 piping from header

[racerx]

What I did for my Celica 75 was that I took my magnaflow to the muffler shop and had the muffler temp. installed then I started the car and rev up the engine..the I had him temp. intall cherry bombs (glasspacks), flowmasers, other turbos and the magnaflow sounded the best. Dynamax also sounded good. The reason why I now stay away from glasspacks is that I got pulled over one time with my 510 which has glasspack and the police officer said that it's too loud..luckily, he received an emergency call and let me go. Also the ricer mufflers, the ones with the big ass tips, they are too loud, too.

 

It boils down to personal preference...and of course how much money you have. A mufller, exhaust header and 2.25 piping will set you back about $600 and this will vary,,like stainless steel piping, exhaust and so on.

[kiznook]

I loved the sound of my spintek on my truck. deep sound and very free flowing.

[5&dime720]

Based on other forums I belong to and because I have never used it, I decided to check it out.

 

 

Thanks for sharing!

[DISLEXICDIME]

GO WITH 3 INCH! hell my l18 is going to need 21/2 to breath right check out this one with 3 inch it has 150 at the wheels and all it has is intake and exhaust up grades

 

http://home.comcast.net/~suchy3072/610build/Page%209.htm

[banzai510(hainz)]

I think 3 inch is to much on a L18. The BRE car never had 3 inch and that was a TOP MONEY car

 

that 610 is BADASS. Maybe quicker on the street if had a better gear ratio on the diff. Sounded like it took a while to get up to speed. I got the same proplem with my 510,3.70 Suby diff.

[DISLEXICDIME]

i am not going three i am going 2.5 i think 3 is to much also.:)

[Z-train]

There is no 4 cylinder made by Datsun that needs a 3 inch pipe.Going too big will actually hurt performance.

[Cuts metal like mad]

There is no 4 cylinder made by Datsun that needs a 3 inch pipe.Going too big will actually hurt performance.

 

For once... we agree. Backpressure on an N/A car is a good thing, it helps with low end torque, and anyone with a 4banger could always use more of that... especially on a street car.

[Z-train]

For once... we agree. Backpressure on an N/A car is a good thing, it helps with low end torque, and anyone with a 4banger could always use more of that... especially on a street car.

 

Yep.Back pressure to a "degree"is good.My current build(LZ-23) will have a 2.25 headpipe into an as yet un-determined muffler and 2 inch tail pipe.

[datzenmike]

Doubling the diameter will increase the cross-sectional area by 4 times.

Changing from a 2" to a 2.85" pipe will double the flow capacity. Look it up.

[Z-train]

Doubling the diameter will increase the cross-sectional area by 4 times.

Changing from a 2" to a 2.85" pipe will double the flow capacity. Look it up.

 

Mike-i'm not questioning the flow capability of the pipe.Rather i'm saying "you"don't need that flow.And actually "all that flow" will actually hurt HP/torque.Now while for MY motor,2 inch is a bit on the anemic side,2.85 is way too big.

[datzenmike]

Sorry, should have said that I agree. Pipe size... easy does it. Just showing that a small increase will make a big difference in flow. The 720 with the Z24 uses something like a 1 3/4" inner pipe size.

 

So on that KA dyno chart the muffler had almost no effect below 4,000 and there was only 8? HP difference @ 5.500. Bet there isn't much difference between a 2" and a 3" pipe either. A smaller L20B would be even less. No one wants to hear that the $400 3" system flows as well as a stock below 4-5,000. And the gain is 5 hp (or what ever) no gain at driving speeds. 2-2 1/2" pipe with big radius bends, largest muffler in the shop, call it good.

[Z-train]

Now i got ya.What ever size the collector necks down to from the factory is what i'm going to use.I think it's 2.25.If it's 2 inch-i'll go with that.Any tail pipe bigger than 1.75 will do nothing except increase noise.

[nismopu]

Also it depends on the bends as well. I have seen/defended the 3" KA exhaust but it has so many variables involved. Plus, I will keep my bottom end power and sacrifice the lousy 8hp. peace.

[Z-train]

Also it depends on the bends as well. I have seen/defended the 3" KA exhaust but it has so many variables involved. Plus, I will keep my bottom end power and sacrifice the lousy 8hp. peace.

 

 

Bends are restrictions.There is a major difference between restrictions & back pressure.Some back pressure is a good thing.Restrictions are never a good thing.

 

On a U67 head there is a little"depression" between the center exhaust ports.While the header/manifold is flat.This leaves a tiny area for "cross-talk between the ports.If this is eliminated,the result is a gain of 10 ft lbs.

[DISLEXICDIME]

There is no 4 cylinder made by Datsun that needs a 3 inch pipe.Going too big will actually hurt performance.

 

ok so what if my l18 has z valves is ported and polished and has 11.5 to 1 compression and is bored 30 over what size exhaust do you guys think it should have?:)

 

i say it need 21/2 because there is a a z20 with a w53 haed with flat tops and z car valves sitting in my back yard with 21/4 exhaust to a magniflow in my back yard and that exhaust is to small

[Z-train]

i say it need 21/2 because there is a a z20 with a w53 haed with flat tops and z car valves sitting in my back yard with 21/4 exhaust to a magniflow in my back yard and that exhaust is to small

 

 

What tells you it's too small?