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Topic: Boy am I exhausted....
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]2eDeYe
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bullet Topic: Boy am I exhausted....
    Posted: 15 March 2006 at 9:45pm

I got some new exhaust on my DD. 1.75" all the way back.
Some of it will need to be reworked, but it's better than the stuff I was draggin around

Starting from the front...and no laughing at my peeling paint

L16 intake (port matched) and exhaust...

Down tube - torsion bar clearance... this will be reworked for more clearance...

Mid-crossmember clearance...Reworking this spot completely as well.
Got to index the torsion lever's, trim off the extra threads and pick up some locking nuts.



Rear crossmember clearance.



Muffler brackets, yes it's a cherry bomb...and it sounds pretty damn cool to me



Outback...

All in all I'm happy with the 'rush' job I had to get done in order to get back on the road. Monday is rework day, I'll have better pic's and more clearance after that.

No more exhaust scraping the speed bumps...of course, now I'm scraping other stuff. One step at at time I guess...
dos datsuns
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Ryan in Seattle
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bullet Posted: 15 March 2006 at 9:57pm
schnazzy............
1973 620 "Prerunner"
L20B,A87,5spd.Lynx,40dcoe,
header,cammed & bored.
zx oil pump,starter,headbolts
& water pump/pulley.
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pac. coast 521
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bullet Posted: 15 March 2006 at 10:14pm
I like the way you ran the pipe on top of the 1st crossmember. Ill have to do mine the same way when the time comes.
My 1965 L 320 {all original}

69 L 521 w/KA swap
94 Hardbody [custom]
74 620 project
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71-521
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bullet Posted: 15 March 2006 at 10:29pm

nice job...

you did this yourself?

 

71 Datsun 510
71 Datsun 521

DAT B-day BBQ
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Driftn620
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bullet Posted: 15 March 2006 at 10:50pm
nice work... but 1.75? damn ... I can only imagine the pain it's gonna be to redo my 2.5inch exhuast and get it tucked up out of the way
1986 camry - decent stocker driver
1965 F100 - custom, was dads
1973 Yamaha 650 chopper - now a family member 20+ years
1978 620 kingcab - Rally build!
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tdaaj
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bullet Posted: 17 March 2006 at 3:59am

you should only go 2 1/4" max unless you're working with a v8. otherwise you lose important back pressure.

 

 

 

 

 

 

 

 

 

 

 

 

 
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]2eDeYe
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bullet Posted: 17 March 2006 at 11:30pm

Wow deletoness....

So I had a shop run it for me. It was a rush job and I wasn't able to go over the routing with it on a rack.

Monday I'll be able to have the guy I wanted to do the exhaust origionally do the rework, while I'm there gettting in his way.

Hainz...You asked about the muff...it's a che, che, che, che, Cherry Bomb. Sounds pretty tuff  

2.5" may fit where I want the tightest spot run, but that's alot of pipe...My somewhat built AMC 360 runs 2.5" and that's the max I would go on my CJ.
dos datsuns
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Driftn620
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bullet Posted: 23 March 2006 at 11:53pm
[QUOTE=tdaaj]

you should only go 2 1/4" max unless you're working with a v8. otherwise you lose important back pressure.



wow that was a totally blind and false statement but sure

what about turbo cars?... high revving s/c cars? that air's gotta get out as fast as it gets in

what about V6's?

every engine responds differently to exhuast diameter size, even how many bends are in it... and usually I keep quiet about it but I can't any more... back pressure is BAD.. HOWEVER still having some backpressure in the exhuast system is a byproduct of having proper velocity.. this ofcourse only applies for an N/A car ofcourse... Boosted engines basically run as big an exhuast as you can afford (without being stupid)

ANYWAYS

if space was an issue, and you weren't doing much more then basics on your truck 1.75 is just fine... my comment was mainly aimed at how much of a PITA rerouting my 2.5inch exhuast with how low my trucks being dropped
1986 camry - decent stocker driver
1965 F100 - custom, was dads
1973 Yamaha 650 chopper - now a family member 20+ years
1978 620 kingcab - Rally build!
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Ryan in Seattle
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bullet Posted: 24 March 2006 at 6:46pm
Backpressure is bad? you're a fool. How many 4 bangers have you worked on? It's true for turbo cars, but other than that............Enjoy you're 2.0 with a 2.5 in exhaust, and don't say you weren't warned.
1973 620 "Prerunner"
L20B,A87,5spd.Lynx,40dcoe,
header,cammed & bored.
zx oil pump,starter,headbolts
& water pump/pulley.
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Bre620
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bullet Posted: 24 March 2006 at 8:17pm
Originally posted by Driftn620

wow that was a totally blind and false statement but sure


nice reply...you'll likely just gain noise. Spend the extra $$$ and get a decent muffler.


1969 510
1972 510
1969 L521
1979 620 4x4
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datsunaholic
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bullet Posted: 24 March 2006 at 8:22pm
If backpressure was wanted then you'd have throttleable exhausts.

The problem with wide-open or overly large exhausts is lack of velocity, which causes a lack if exhaust flow, which in turn causes waste gasses to stay in the cylinders.

But too much flow is bad too. Burned valves can happen either way. It's a flow thing, not a pressure thing.


Now, on a 2-stroke it's a whole 'nother story.
'64 320
'68 520
'72 521 V6
'74,75,79 620s
'76,78 4X4
'76 KC
'72 510 Wgn
'78 B210
'78,81 510 Wgn
2X '78 510 Coupes
'83 720 KC

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]2eDeYe
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bullet Posted: 24 March 2006 at 11:00pm
My truck uses oil like a two-stroke bitch
dos datsuns
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Driftn620
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bullet Posted: 25 March 2006 at 2:21am
Originally posted by Ryan in Seattle

Backpressure is bad? you're a fool. How many 4 bangers have you worked on? It's true for turbo cars, but other than that............Enjoy you're 2.0 with a 2.5 in exhaust, and don't say you weren't warned.


how many have I worked on... ummmm how about 14-20 a DAY

other factors into exhuast size are the RPM range your engine is being built to run... if I wasn't building the truck to set off above 5K rpm that often, I would go with a 2.25 exhuast, the 2.0 in my 620 pulls all the way to 7K rpm it USES that 2.5 inch exhuast. Make NO mistake I am not some newbie kiddy getting a hard on over 3inch exhuasts with 4+inch tipped Cans on close to bone stock 4bangers.

the best exhuast is one that rides the fine balance of velocity and byproduct backpressure, in your desired RPM range. from this you will get your maximum hp gains in the rpm range your using and added throttle response in a properly tuned engine with matched parts
1986 camry - decent stocker driver
1965 F100 - custom, was dads
1973 Yamaha 650 chopper - now a family member 20+ years
1978 620 kingcab - Rally build!
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