02-05 Exhaust Manifold versus 08-09 Exhaust Manifold

[redmaro42]

This is stemming from the Kooks go green or not thread where we were comparing manifolds. Thought I'd start a different thread instead of hijacking the other. Wow what a difference between the two manifolds. I ordered a dorman 674-777 (02-05) exhaust manifold and a dorman 674-869 (08-09) exhaust manifold yesterday to see the difference between the two as a possible performance upgrade for the earlier models. Oxygen sensor placement on the 02-05 is located in the exhaust manifold, the 08-09 have moved the oxygen sensor placement into the pipe in front of the converter.

02-05 manifold


08-09 manifold


Question #1: Is there enough length on the pigtail to reach the pipe instead of the manifold on a 02-05?
Answer: TBD

Now for the gaskets, as you can see the ports on the 08-09 are much larger than the 02-05 gaskets.





Then there is the manifolds. Check out the port sizes and shapes, the 08-09 definitely have larger ports and will be flowing a lot better than the crude 02-05 version. Also the inside of the ports are very rough, Dorman didn't do a good job manufacturing and cleaning the ports out. Either manifold would benefit greatly from porting the ports to smooth the roughness out. The 08-09 version also has a split in the center bolt spot to allow some movement and/or relieve stress.

Left is 02-05 Right is 08-09




02-05 port closeup


08-09 port closeup


Question #2: Anyone have a side by side comparison of the ports on a 02-05 cylinder head and a 08-09 cylinder head to see if their ports are this much different in size as well?
Answer: TBD

Conclusion: (So far, need more testing, confirmation)
If the ports are the same on the cylinder head, enough length on the oxygen sensor to move to the pipe and you have access to a shop to weld in an o2 bung on the pipe, then a change to the 08-09 version manifold should net a reasonable performance gain without paying the big bucks for a Kooks header system and keep the stock sounding exhaust. Of course a header is still going to give you even more power but this could be a reasonable alternative for those with cracked manifolds and not looking to spend 700-1000 bucks on a header.

 

[rocketsound]

Interesting... even if the ports on the head are smaller, that would flow more. I might try this just to see.

 

[Mounce]

Nice studies, indeed. I wonder if anyone else has looked into this. Looking forward to where you go with this.

 

[redmaro42]

I tried searching here, trailvoy, etc but haven't had much luck with proven results one way or the other. Just curiosity mainly that got me thinking about this and the hp improvements in the newer years. If there was a cheaper alternative than Kooks for a header, then that would be great too. Just gotta use what we have available lol. A ported 08-09 manifold might be a great bolt on mod if we are able to test it and show gains.

 

[Playsinsnow]

Interesting. Waiting for your results!

 

[redmaro42]

Interesting. Waiting for your results!

This is just a research project so far, mine isn't cracked and leaking so I am not trying to remove it yet lol. Don't need to tackle broken bolts if I don't have too. lol

 

[HARDTRAILZ]

I wonder with the 06 bump in HP if they which style they have or if they are different as well.

 

[redmaro42]

06 is similar to the 02-05, hence why I just compared to the 08-09 manifold, the ports do appear closer to the 08-09 version on the 06-07 ones, but the runners are not as large, they appear closer to the 02-05 style

Here are the three different designs:

02-05

06-07

08-09

 

[HARDTRAILZ]

Right on. May be time for an upgrade as preventative maintenance

 

[Envoy_04]

Will the movement of the O2 sensor to a different location throw off the PCM?

Also, it appears the 08-09s had a pre-cat and a cat on the downpipe from the manifold. Though the 08-09 manifold may bolt on to the earlier vehicles, I wonder if the earlier downpipes would line up to it the same? From some searching, it appears 02-05, 06-07, and 08-09 all had their own different downpipes (cat pipe, whatever it's called).

Also, am I the only one who thinks the 08-09 manifold would be downright sexy smoothed up a little, heat shield ditched, and then ceramic coated?

 

[24v 4.2]

Also, am I the only one who thinks the 08-09 manifold would be downright sexy smoothed up a little, heat shield ditched, and then ceramic coated?

I thought the same thing.

 

[Sparky]

I can see why the 08-09 would be less prone to cracking. There is more "stretch room" between banks since it isn't so solid.

06 is when they made a head change, I don't think the head changed again in 08 but I could be wrong.

 

[seanpooh]

I do have a 2002 cylinder head in my garage laying on the floor... I'll take a pic and post it up for future reference for comparison when someone with a later year posts one.

The kooks headers did move the upper 02 sensor to just three cylinders. It doesn't throw a code until you drive it a certain number of miles. I assume the PCM picks up on it.

As for the Kooks headers, I love mine. Maybe it's an investment with the tax refund...
I do know a place where you could get it at the $765 range. Also the gasket that Kooks provides is a thick cloth version vs the stock metal one.

 

[IllogicTC]

I believe the large ports is directly related to the 06 head redesign.

 

[Pittdawg]

It's common knowledge that starting in 06 the cylinder head ports were made more free flowing. I believe they were again improved in 07 and 08. The news to me was that they also improved the manifold ports but in hindsight that makes perfect sense. I have an extrude honed ceramic coated exhaust manifold after my stock 08 manifold cracked. I didn't dyno before and after but I can tell you that along with my Volant intake, ported tb, pcm tune and magnaflow exhaust my ride has a lot more giddy up then when it was stock.

 

[redmaro42]

Will the movement of the O2 sensor to a different location throw off the PCM?

Also, it appears the 08-09s had a pre-cat and a cat on the downpipe from the manifold. Though the 08-09 manifold may bolt on to the earlier vehicles, I wonder if the earlier downpipes would line up to it the same? From some searching, it appears 02-05, 06-07, and 08-09 all had their own different downpipes (cat pipe, whatever it's called).

Also, am I the only one who thinks the 08-09 manifold would be downright sexy smoothed up a little, heat shield ditched, and then ceramic coated?

Moving the o2 sensor down a little bit will not throw a code as it is still monitoring the same airflow. From them sitting side by side they had the same size and angle flange. Measurements all were the same.

The different intermediate pipes are probably due to o2 sensor location and such instead.

Yea an extrude honed one would be even better for flow! Depends though on the 02-05 head ports and how small/restrictive they are though as the air still has to flow through them. Maybe a cylinder head port match to the 08-09 manifold gasket and then the 08-09 manifold would be where the really nice gains would be.

 

[redmaro42]

I do have a 2002 cylinder head in my garage laying on the floor... I'll take a pic and post it up for future reference for comparison when someone with a later year posts one.

The kooks headers did move the upper 02 sensor to just three cylinders. It doesn't throw a code until you drive it a certain number of miles. I assume the PCM picks up on it.

As for the Kooks headers, I love mine. Maybe it's an investment with the tax refund...
I do know a place where you could get it at the $765 range. Also the gasket that Kooks provides is a thick cloth version vs the stock metal one.

definitely curious as to what the head ports look like on it, please post a pic when you get a chance, thanks!

 

[Envoy_04]

Extrude honing is nice, but the point of this is to not spend as much as for the Kooks header, right? By the time you purchase an 08-09 manifold, send it off for extrude honing, and then get it back, then have the O2 bung welded in or do it yourself, you'll have almost as much in it as a Kooks header. If you decide to get it ceramic coated (even though this is a fairly cheap process), youll have spent more than the header price.

Personally, I'd hone out what I could by hand, possibly have it ceramic coated (where the larger HP gain comes from anyhow, aside from the better flow of the manifold itself) and call it done. Just my opinionated 2¢, no offense meant toward anyone.

 

[redmaro42]

Extrude honing is nice, but the point of this is to not spend as much as for the Kooks header, right? By the time you purchase an 08-09 manifold, send it off for extrude honing, and then get it back, then have the O2 bung welded in or do it yourself, you'll have almost as much in it as a Kooks header. If you decide to get it ceramic coated (even though this is a fairly cheap process), youll have spent more than the header price.

Personally, I'd hone out what I could by hand, possibly have it ceramic coated (where the larger HP gain comes from anyhow, aside from the better flow of the manifold itself) and call it done. Just my opinionated 2¢, no offense meant toward anyone.

oh for sure, extrude honing is not cheap either, definitely agree

 

[Pittdawg]

oh for sure, extrude honing is not cheap either, definitely agree

True. However, in my case I got the manifold free under warranty and since I'm here in Cali headers aren't a smog legal option.

 

[redmaro42]

True. However, in my case I got the manifold free under warranty and since I'm here in Cali headers aren't a smog legal option.

Didn't realize the kooks weren't CARB compliant, that sucks. Looks like extrude honing would be your best bet then. Local place by me charges $649 to extrude hone a manifold That seems crazy pricey

 

[Envoy_04]

redmaro, I got off my butt today and did some looking at my 04 and I have an answer to question #1, sort of. It seems that moving the O2 sensor is going to be a larger issue than thought, the pigtail won't let it go that far. Splitting the loom the sensor plug-in lead comes from and pulling the wires for the lead out to gain extra length isn't an option because they run back toward the PCM which is the opposite direction from that which they need to go. Splicing the pigtail isn't recommended due to messing with the resistance of the sensor, but I do see plug in extensions for O2 sensors available, so that might be an option?

I also saw where matching the ports to the newer manifold was mentioned and did some digging. Just hogging out the exhaust ports with the head on the vehicle has been said by efi-diy and turbo4200 on the OS that you'd lose power rather than gain. To do it right so you'd actually gain flow and power from it you'd have to take the head off and bowl blend it and the whole works. Looks like head porting is an "all or none" type deal. Shouldn't matter though, the 08-09 manifold would still flow better simply due to the better design and larger ports, so gains would likely still be noticeable, and for about the same price as the earlier manifold anyhow.

I don't even have a cracked manifold and you've got me seriously considering this.

 

[BlazingTrails]

As far as extending the harness you just need to use the same wire like from an old o2 laying around and solder the wires. It will not mess with the resistance that way. Also they make splice kits with set screws that work well. It is not very easy soldering the steel wire, has to be much hotter and different flux. you can order o2 bungs on ebay really cheap as well, if you mark where you want the bung and then remove the pipe you can drill the hole yourself and then take it to a shop and get it welded on for cheap.

Luckily I have my own mig welder


O2 Bung Ebay

 

[redmaro42]

Yea easiest route would be o2 extension like Camaro guys run with headers. Just would need to find the right plug style and length. Better than splicing and chancing inaccurate readings.

 

[BlazingTrails]

I agree with you for under $20 it is PNP and would be a simple solution. Extending the wires for me is a no brainer though simply because I have everything I need in the shop.

Extension Harness Ebay

 

[SkidMark]

This is awesome, redmaro42. Thanks for taking one for the team and ordering both.


As for the other issue, does an O2 sensor for a '08+ already have enough wire to reach? If so, wouldn't that work? It would be a little more $ than the extension cable but wouldn't have issues as it was designed that way plus you get the added benefit of having a new sensor.


Thanks everyone!


Regards,

Mark

 

[redmaro42]

This is awesome, redmaro42. Thanks for taking one for the team and ordering both.


As for the other issue, does an O2 sensor for a '08+ already have enough wire to reach? If so, wouldn't that work? It would be a little more $ than the extension cable but wouldn't have issues as it was designed that way plus you get the added benefit of having a new sensor.


Thanks everyone!


Regards,

Mark

Not gonna be enough. I looked up the lengths of the NGK upstream o2 sensors for 04 and 08. The 21054 sensor that fits 2004 trucks is 18.75" long, the 21561 sensor is 19.75" in the 2008s. So 1" isn't going to be enough, better off spending 10-20 bucks on extensions instead.

 

[Wooluf1952]

I'm not a welder, but, would it be possible to braze or weld a bung to the newer manifold? Same location and a harness extention wouldn't be needed.

 

[Mounce]

Possible, yes. Whether it would work alright (if the PCM would be happy) is beyond me.

 

[Sparky]

You could move it down to right before the cat and it should work fine as the exhaust isn't any different in composition there vs right at the manifold. Only requirements is it sees exhaust from all cylinders and it is close enough to get hot enough.

 

[redmaro42]

I'm not a welder, but, would it be possible to braze or weld a bung to the newer manifold? Same location and a harness extention wouldn't be needed.

much easier to weld a bung on the exhaust pipe before the converter than to try and drill and weld to the cast piece.

 

[BlazingTrails]

I'm not a welder, but, would it be possible to braze or weld a bung to the newer manifold? Same location and a harness extention wouldn't be needed.

It's been my experience on cast steel that welds crack easier due to the higher expansion rate. In order to weld cast steel you have to heat the entire manifold to operating temps before welding in a forging oven.

You could move it down to right before the cat and it should work fine as the exhaust isn't any different in composition there vs right at the manifold. Only requirements is it sees exhaust from all cylinders and it is close enough to get hot enough.

True story.

 

[bspurloc]

Yea easiest route would be o2 extension like Camaro guys run with headers. Just would need to find the right plug style and length. Better than splicing and chancing inaccurate readings.

It seems odd a few talking about cutting splicing would increase resistance and that an extension is the better option. When in fact an extension is more likely to cause a resistance increase due to you connecting 2 wires together by just touching them together in a connector.
If you want to eliminate any chance of increase resistance, the only option is to clean up the wires and solder them together. dont forget to drop 2 levels of heatshrink on before soldering them. u heat shrink the smaller one down then the bigger one down on that and seal the soldered joint pretty good, then insert into loom.
Doing this 100% eliminates any corrosion over time getting between the connection of the 2 wires and creates a direct link between the 2 wires.
snap together connectors are only uses out of convenience not because they are lesser resistance.
It would be a pain to repair things if you had to desolder the wires from the components.

 

[Envoy_04]

The issue is that the leads of the sensor aren't copper. They are solderable, but not with the average person's soldering skils.

 

[AtlWrk]

Is it possible that the 08+ is just routed a little differently on the engine harness? Instead of running up to the oil dipstick bracket then back down to the sensor you could just run straight to the sensor and support the harness/connector elsewhere.

Also, let's step back for a second: soldering (done right) versus an extension is going to be a wash in terms of resistance.

A. the sensor circuit is a near-DC, high impedance, voltage measurement. In other words, nearly zero current is flowing so resistance is irrelevant.

B. There are reports of different brand O2 sensors throwing heater performance DTCs so I'm not sure how far you can deviate before setting a code BUT Delphi specs their 150 series connectors at <10milliOhms. Even if they're an order of magnitude worse than that you're still talking only a few percent overall compared to the heater's resistance.

Point being, whichever method you're more comfortable with, do it.

 

[bobdec]

Just to add some insight... post #34 said "The issue is that the leads of the sensor aren't copper. They are solderable, but not with the average person's soldering skils."
To add more to this ... A general rule is never to splice into the O2 end of the wiring harness. The O2 requires outside air (O2 supply) for a reference measurement against the exhaust to operate correctly. That outside air is supplied by a very small channel in the sensor wire insulation, air enters at the connector end. Plugging that path (solder/tape/sealant)will make the O2 inoperable. Therefore any splicing should be done on the PCM side of the O2 connector. Also agree that a good solder joint will not effect the resistance, it's a common practice when adding headers. However after using both IMO extensions are the fastest, easiest and safer way to go.

 

[swede]

Just to add some insight... post #34 said "The issue is that the leads of the sensor aren't copper. They are solderable, but not with the average person's soldering skils."
To add more to this ... A general rule is never to splice into the O2 end of the wiring harness. The O2 requires outside air (O2 supply) for a reference measurement against the exhaust to operate correctly. That outside air is supplied by a very small channel in the sensor wire insulation, air enters at the connector end. Plugging that path (solder/tape/sealant)will make the O2 inoperable. Therefore any splicing should be done on the PCM side of the O2 connector. Also agree that a good solder joint will not effect the resistance, it's a common practice when adding headers. However after using both IMO extensions are the fastest, easiest and safer way to go.

You beat me to it, I was going to say the same thing. Good post [emoji106]

 

[BlazingTrails]

I had another manifold crack on me! originally an 05 manifold then I replaced it with an 06' manifold which lasted 2 weeks over it's warranty.

I purchased an 09' manifold and some heat wrap. just to confirm for everyone the fit, the downpipe will need to be modified heavily to fit. the manifold flares out about 2.5" further than the original. so I had to fab a different down pipe. seems to be doing great so far, intake and tranny temps are down and if you saw these in person you would agree that the flow would have to be 100% better. Just not sure if that will make much difference on the 02-05 heads due to the smaller exhaust ports. Questions?

 

[BlazingTrails]

Sorry for the double post....tapatalk.

Mod please combine?

 

[Tiggerr]

Wouldn't the down pipe from an 08-09 work instead of welding into the old one? I thought all the cats were were in the same place on all years. Pretty sure the cat back exhausts fit all years. The angles being off is probably why the pipes are different and the O2 bung.