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Ebay Sohc Header

Posted: Mon May 21, 2012 1:27 pm
by heydockyle
At work. Don't feel like searching. Few headers for 00+ Sohc's on ebay In the 85$ shipped for the header, gaskets, and a downpipe range.

http://www.ebay.com/itm/00-01-02-03-04- ... 38&vxp=mtr

Don't want the downpipe, anyone had any success using these headers with stock cat?

Posted: Mon May 21, 2012 1:59 pm
by RobsProjectSOHC
I just bought one the other day, once i get it ill tell you. gunna be about 1-2 weeks before i get it.

Wanted something for now....turbo manifold future so ebay one is what ever to me.

Re: Ebay Sohc Header

Posted: Mon May 21, 2012 2:19 pm
by heydockyle
Oops

Posted: Mon May 21, 2012 2:22 pm
by RobsProjectSOHC
thats the one i bought, from the same people.

Posted: Mon May 21, 2012 2:45 pm
by heydockyle
Tried to edit my post. Not sure how it got quoted and replied lmao.

Posted: Mon May 21, 2012 9:53 pm
by dvon17
yea, I'm gonna stay posted on this thread. I'm interested in that header as well. Be sure to keep us posted on how it works out for you bro.


:rockon:

Posted: Tue May 22, 2012 1:45 pm
by Dranz
You really won't see much power from this type of header. The tubes are waaaay too short for any kind of scavenging effect at anything under 10,000rpm. And don't get me started on the horrible dump type collector they use. It's an ok substitute for the stock manifold, but nothing more. It's maybe a 1-2 hp gain if you're lucky. Even that gain is only if you gasket match it and grind down some of the nasty turbulent welds in the ports and try to at least smooth the transition from the pipes to the dump. The only plus side is it looks much nicer than the stock peice.(till you turn it purple and it starts to rust!) Been there, done that, sold it to a ricer and bought a long tube.

Posted: Tue May 22, 2012 1:48 pm
by dvon17
So long tubes are definitely the way to go? Lol.

Posted: Tue May 22, 2012 2:41 pm
by Dranz
For power, hands down a long tube with a merge collector. But bang for the buck goes to a long tube with a dump collector. Get in there with a dremel and clean up any ugly welds, gasket match it, and clean up the dump collector. For around $200 you can have a decent bump in power.

Posted: Tue May 22, 2012 6:24 pm
by ragek23
It will work with the stock downpipe with a little modification. just make sure the o2 sensor has enough room against exhaust tunnel. I liked that fact that these were cheap but that's exactly what they are. I have had 2 rust out on me in the last 4 years. I am going to a pacesetter with a ceramic coating next. It has a better collector design too so I am hoping for a little more gains. especially being coupled with a fresh 2.5 catback and hi-flow cat.

Posted: Wed May 23, 2012 8:36 am
by heydockyle
Don't care about gains. Going on a daily driver. Stock one is leaking/ugly.


Will also powdercoat it high temp black. Should hold up.

What all modifications?

Posted: Wed May 23, 2012 2:00 pm
by Donkeypuncher
The long tube is just too much of a hassle for a daily driver, plus it makes your car sound like poop. I'm going back to an obx shorty header to quieten it down and get back some low end power.

Posted: Wed May 23, 2012 8:20 pm
by Dranz
I don't understand how the long tube is a hassle... You replace the manifold and downpipe with the long tube. If you don't want the "poop" sound, you attach a resonator to the front of the lth and hacksaw the mid pipe and clamp it... How do you base your findings of the sth having more low end than the lth? Is it because you bought the first lth that you could find cheap with 1 7/8 primaries? Lth with the same diameter primaries have more low end because they are designed to scavenge at lower rpms than the shorties. Tube diameter is a factor of effective rpm range as well as length. You would be very suprised how much low end you could have with 1 3/4 or 1 5/8 primaries. Short tube headers are worthless. You will never see the rpm ranges where a short tube would be efficient. The only reason a short tube should be used is where space is an issue.

Posted: Wed May 23, 2012 8:23 pm
by RobsProjectSOHC
I bought this so I can use till turbo set up next year.

I received tracking number but says not tracked. Careful buying just yet.

Posted: Wed May 23, 2012 8:26 pm
by Dranz
I'm doing the same thing with my build. It's getting a cheap sth so when I'm ready it can be replaced with a turbo manifold. Misplaced some words up there^. Damn you autocorrect!

Posted: Wed May 23, 2012 8:38 pm
by OB
Dranz wrote:I'm doing the same thing with my build. It's getting a cheap sth so when I'm ready it can be replaced with a turbo manifold. Misplaced some words up there^. Damn you autocorrect!
You said short tubes are worthless in your last post, but you're buying one as well? Interesting.

I don't understand why one would buy a cheap part, take the time to install it, then replace it with what they really want down the road. Why not just buy what you want up front, or save until you can afford it if budget is an issue? Being impatient has never produced a quality built car and never will, unless money grows on a tree in your backyard.

Good luck :thumbup:

Posted: Wed May 23, 2012 8:52 pm
by Donkeypuncher
Shorty header: bolts right up with no modification.

Long tube header: Need to be welded, need a high flow cat, O2 bung, extend O2 wires, weld in a resonator (optional), weld on better collector (optional).

That's why I say it's too much hassle for a daily driver. For me it's not worth the few extra hp you get, but to each their own.

Posted: Wed May 23, 2012 8:56 pm
by RobsProjectSOHC
The only plus side is it looks much nicer than the stock peice.
Good enough for me

Posted: Wed May 23, 2012 9:30 pm
by Dranz
OB wrote:
You said short tubes are worthless in your last post, but you're buying one as well? Interesting.

I don't understand why one would buy a cheap part, take the time to install it, then replace it with what they really want down the road. Why not just buy what you want up front, or save until you can afford it if budget is an issue? Being impatient has never produced a quality built car and never will, unless money grows on a tree in your backyard.

Good luck :thumbup:

Because a used dohc shorty for $15 doesn't bother me. That will allow me to swap the 2.4 in and run it without the turbo for a week or two while I'm getting odds and ends set. It's more important for me to build this in stages than to swap everything at once and rush it. I'm also modifying a 1st gen dp so it can be a bolt an go affair when the engine is broken in and no leaks are found.

Posted: Wed May 23, 2012 9:49 pm
by Dranz
Donkeypuncher wrote:Shorty header: bolts right up with no modification.
For power they offer not much over the stock manifold.
Donkeypuncher wrote:Long tube header: Need to be welded, need a high flow cat, O2 bung, extend O2 wires, weld in a resonator (optional), weld on better collector (optional).
None of this is mandatory... Most lth have a bung for upstream halfway down one of the primaries right where the stock unit would be and another for the downstream at the collector. Exhaust clamps work quite well to attach the lth to whatever you chose to attach it to.
Donkeypuncher wrote:That's why I say it's too much hassle for a daily driver. For me it's not worth the few extra hp you get, but to each their own.
A lth takes maybe five to ten minutes longer to install than a sth. Bang for the buck would best be spent elsewhere... But yet again, to each their own...

Posted: Wed May 23, 2012 10:26 pm
by heydockyle
Five to ten minutes longer? Have you ever installed a long tube onto a stock exhaust...?

Posted: Wed May 23, 2012 11:03 pm
by occasional demons
Dranz wrote: Most lth have a bung for upstream halfway down one of the primaries right where the stock unit would be and another for the downstream at the collector.
Only sampling one cylinder isn't the wisest choice. What if one of the the other cylinders has an injector fail, flooding the cylinder? The o2 will never see it.


And scavenging? Only effective with a crane 14, or something with overlap. Any of the smaller cams have zero overlap, so scavenging is not gonna happen. Both valves must be open at the same time to scavenge.

Posted: Thu May 24, 2012 12:08 am
by Donkeypuncher
I don't think our engines rev high enough to really take advantage of a lth, especially with the non r/t.

90% of the time I'm between 2-5k rpms when accelerating, so the lth isn't ideal for me. With a 8k rpm rev limit and a cam things might be a little different.

Posted: Thu May 24, 2012 7:37 am
by Dranz
heydockyle wrote:Five to ten minutes longer? Have you ever installed a long tube onto a stock exhaust...?
Yes I have. The only difference installing a lth over a sth, is removing the dp. This can be done with a healthy application of penetrating lubricant and heat. This would also work for the downstream O2. The mating joint between the lth and the stock mid pipe often requires an adapter from 2.5 to 2.25. Nothing else is required.
occasional demons wrote:Only sampling one cylinder isn't the wisest choice. What if one of the other cylinders has an injector fail, flooding the cylinder? The O2 will never see it.
If an injector fails and floods the cylinder, this may cause a misfire, which would send pure gas and fresh air into the exhaust. The oxygen sensor would then see the burst of fresh air, as the gas would not be a homogenous mixture entering the exhaust due to high exit velocities through our exhaust ports, and it would tell the PCM to go richer with the mixture. If this problem was let to continue, this could wash the cylinder walls of oil and create an issue where there is no oil on the exit stroke or the compression stroke of the power cycle. This could lead to ring damage and a destroyed cylinder lining. It would be no different if the one cylinder the lth O2 was sampling was misfiring. There really isn't much benefit that i can think of at the moment of having the O2 at the collector over having it in a primary. If the vehicle isn't running correctly the owner should fix it, as the O2 and PCM alone are not capable of fixing such an issue.

Posted: Thu May 24, 2012 9:46 am
by occasional demons
If it is half way up the tube, like most LTH are, the o2 will not see a rich/lean mix from the other cylinder. It isn't going to flow up the pipe. You are only reading one cylinder. One member a while back ended up with a hole in his piston running from one cylinder input.

Posted: Thu May 24, 2012 10:58 am
by Dranz
occasional demons wrote:And scavenging? Only effective with a crane 14, or something with overlap. Any of the smaller cams have zero overlap, so scavenging is not gonna happen. Both valves must be open at the same time to scavenge.
The scavenging effect I'm referring to is not pulling fresh air into the cylinder but rather creating a negative pressure wave up the other primaries after a high pressure exhaust wave exits its own primary tube. At a specific rpm range, this effect will actually hit the exhaust valve right when or slightly after it opens. This low pressure wave will help suck the exhaust out of the cylinder.
Donkeypuncher wrote:I don't think our engines rev high enough to really take advantage of a lth, especially the non r/t. 90% of the time I'm between 2-5k rpms when accelerating, so the lth isn't ideal for me. With a 8k rpm limit and a cam things might be a little different.
Actually, between 2-5k is right in the meat of where a correctly tuned lth really shines for power over a sth. A longer tube means a lower tuning resonance, which shows that longer tubes are better for lower rpms than shorties. Having short tubes ends up with a resonance frequency too high for our sohc. The negative pressure waves have already bounced off the valve and already are dispersed in the collector before the valve opens again.

Posted: Thu May 24, 2012 11:41 am
by Dranz
occasional demons wrote:If it is half way up the tube, like most LTH are, the o2 will not see a rich/lean mix from the other cylinder. It isn't going to flow up the pipe. You are only reading one cylinder. One member a while back ended up with a hole in his piston running from one cylinder input.
Are you blaming a hole in a piston on an incorrectly positioned oxygen sensor? Was the hole in the piston caused by an incorrect reading of the O2? Most likely not. Might it have been caught if his upstream O2 was reading all 4 cylinders? Again, this would have to be caught by the driver... The O2 can't fix a problem like that. If the O2 was in the collector, it might adjust fuel to the rich side to adjust for the misfire and/or lean condition. My point is, a cylinder specific mechanical problem is generally not caught by an oxygen sensor...

Posted: Thu May 24, 2012 11:54 am
by Donkeypuncher
Image

Posted: Thu May 24, 2012 12:05 pm
by Danteneon
Dranz wrote:
occasional demons wrote:If it is half way up the tube, like most LTH are, the o2 will not see a rich/lean mix from the other cylinder. It isn't going to flow up the pipe. You are only reading one cylinder. One member a while back ended up with a hole in his piston running from one cylinder input.
Are you blaming a hole in a piston on an incorrectly positioned oxygen sensor? Was the hole in the piston caused by an incorrect reading of the O2? Most likely not. Might it have been caught if his upstream O2 was reading all 4 cylinders? Again, this would have to be caught by the driver... The O2 can't fix a problem like that. If the O2 was in the collector, it might adjust fuel to the rich side to adjust for the misfire and/or lean condition. My point is, a cylinder specific mechanical problem is generally not caught by an oxygen sensor...
I think you are going a little out of bounds on this. Bill isn't saying that the O2 would cause or would correct the problem, but rather there would have been some advance notice that something wasn't right. The CEL would light, and the problem could be diagnosed before any real damage occurred. This is of course best case scenario. With the O2 reading only one cylinder, it would have no way of knowing what was going on in the other three.

Posted: Thu May 24, 2012 12:56 pm
by Dranz
It is true that reading one cylinder takes the other three out of the equation. However, a malfunctioning injector causing a lean condition will more likely trimmed up on fuel for all the cylinders masking the original problem. The standard narrow band sensor uses millivolts and has a very narrow reading area. It is unlikely that a slow switching planar sensor will catch a problem with one cylinder. Fuel trims on our vehicle can reach +/- 25%. More than enough to fool an oxygen sensor into thinking everything is fine. You guys are giving this type of sensor way too much credit.