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Underbody braces, turbos and more!

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PostPosted: Fri Mar 13, 2009 9:55 pm 
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Joined: Mon May 14, 2007 12:47 am
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Location: Prescott, AZ
I haven't laid a straight edge on it yet, but I am pretty sure that the low heat used in the tig weld wouldn't warp it anymore than what it perhaps came with. I too am worried about the length of the header unsupported, so I am probably going to weld a tab on it to hang from the original hanger just behind the transmission. it's an awful long way back to the 2nd hanger on the resonator!


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PostPosted: Mon Mar 16, 2009 3:18 pm 
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Location: ajax, ontario, planet bullsh**
forgive me for a potentially stupid question, but why would bypassing the egr burn valves? far as I know the egr valve only recirculates the exhaust in order to warm up the motor faster.


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PostPosted: Mon Mar 16, 2009 7:11 pm 
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i think that part of the "magic" involves the fire deck temperature in the cylinders. the exhaust gases are hot as they exit but when they are re-introduced into the intake side, the effect lowers the fire deck temps because they help to fill the volume of the cylinder, in part, with a gas which has a very reduced oxygen content but about 70 - 80% unconsumed hydrocarbons.

that, in part, leads to higher fuel efficiency due to the recycling of unburnt fuel and, to a large degree, less oxygen to drive the internal cylinder temps up. in the tbi equipped cars, the addition of recirculated, hot gases helps to vaporize the raw fuel as well.

g10 engines that suffer from burnt exhaust valves, in my personal experience, have been those that had the egr passage in the head completely clogged with soot and, subsequently, were driven at highway speeds on a regular basis. once an exhaust valve gets a small burnt spot, it starts to erode faster and faster from the constant bypassing of hot gas until compression is impaired. if you never allow the fire deck temperature to the point where the thin edge of a valve face, at it's contact point with the valve seat starts to melt, the valves will only see normal mechanical wear.

i've had engines, built for the leaded gas days but operated on unleaded fuel, that would actually get so hot that the valves would weld themselves to the seat area. when the cam forced the valves open, little chunks would get torn out of the seat. the valves would eat further into the seat until valve regression would outstrip the ability to adjust the valve lash any more. older gas formulations which used tetra-ethyl lead, in practice used it to maintain fire deck temps by plating out the lead on the valve face edges and in the valve seats to create a self-effacing, replaceable seal for the exhaust valves. with newer engines, the design engineers use harder alloys for valves and seats to ameliorate mechanical wear without the advantage of leaded fuel. they have also lowered compression ratios and decreased fire deck temperatures to prevent damage. the design problem tends to become how to maintain engine efficiency as well as fuel efficiency and usually, the answer is to run the engine as lean as you can. unfortunately, that raises the fire deck temps. in suzuki's inimitable engineering elegance, they used the egr circuit to milk fuel economy by re-burning the exhaust gas as well as reducing fire deck temps due to the reduced excess o2 in the recirculated gas.

the turbo3 cars don't use an egr system but they have an additional catalyst right after the turbo that helps to complete the incineration of unburnt fuel and a secondary cat converter to take care of the other exhaust gas components.

i've read some other stuff in the bosch automotive engineering handbook with regard to the application of an egr circuit, largely based on vw and porsche designs. the egr technology was employed back in the late 70s and throughout the 80s in a lot of european engine designs, especially in conjunction with early mechanical fuel injection systems when they used a lambda sensor and analog controls. i recall that the vw systems had a dash indicator that timed egr service intervals and required the service technican to reset the idiot light. suzuki just listed the service interval based on mileage. i guess that if the interval wasn't observed and the egr system wasn't serviced, the owner took his chances on burnt valves.

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PostPosted: Mon Mar 16, 2009 7:30 pm 
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Joined: Mon May 14, 2007 12:47 am
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Location: Prescott, AZ
Kickin45 wrote:
I haven't laid a straight edge on it yet, but I am pretty sure that the low heat used in the tig weld wouldn't warp it


Well I laid a straight edge on it, and as I assumed, the weld didn't warp the manifold.....unfortunately, the welds that SRD did.....did.
so like so many others it's off to the machine shop to get the headflange machined flat, has anyone reported SRD to the BBB???? cause this company sure doesn't provide what they advertise.


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PostPosted: Wed Jun 10, 2009 11:53 am 
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Joined: Wed Nov 26, 2008 9:43 pm
Posts: 183
Location: mn
amazing.
where did you aquire that header?

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PostPosted: Wed Jun 10, 2009 1:07 pm 
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Joined: Tue Jul 06, 2004 12:13 pm
Posts: 219
Location: SEATTLE,WA
Another reason for the burnt valves was the use of 10/40 oil. The oil was to thick for the lifters and would cause the lifters to remain "pumped up" longer than they should. Then the valve would not completly close.


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PostPosted: Thu Jun 11, 2009 8:17 am 
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Location: Prescott, AZ
xcoreyishoodx wrote:
amazing.
where did you aquire that header?



From Suzuki Racing Development but I would look for one elsewhere unless you're planning on doing some fab/welding work of your own to make it work on your car...AFTER spending the money to just get it...


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PostPosted: Fri Jun 12, 2009 1:24 am 
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Joined: Mon Jun 18, 2007 1:35 pm
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Location: Regina, SK
Kickin45 wrote:
xcoreyishoodx wrote:
amazing.
where did you aquire that header?



From Suzuki Racing Development but I would look for one elsewhere unless you're planning on doing some fab/welding work of your own to make it work on your car...AFTER spending the money to just get it...


I had to get mine machined, welded, and shipped to the other side of the country to get ceramically coated.

I could have bought one of Hertz's headers in stainless with the collector spike and had a stainless flange machined and welded on for less than what this header has cost me.

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J. McBean: '98 Suzuki Swift 1.3L 16v SOHC 5sp+ "Mk5" Made in Canada
The Mini Rattler: '94 Suzuki Swift .993L 6v SOHC 5sp+ "Mk3" Made in Canada *The Winter Beater*
B. Berry: '90 Chevrolet Turbo Sprint 1.0L 6v SOHC 5sp+ "Mk2" Made in Japan

I got 18MPG in a 3cyl with a 5 speed manual 4dr, '93 Metro! :yeahyeah


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