Musings after a DT header install

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Joined
Oct 26, 2006
Threads
82
Messages
285
Location
Folsom. CA
After completing the header install on my 2000 LX470 this weekend, I figured I might give my thoughts and opinions so that others who are considering this work can benefit from more discussion.

As a precursor, my LX has been a one owner, California vehicle all of its life as a pavement pounder, never been off-road and well maintained. I bought the vehicle with 101k miles and it had an exhaust leak when I bought it. I ordered the headers from DT, and 16 manifold nuts from C-Dan including the doughnut gaskets that go on either end of the cats. The rig now has 102,400 miles on it, I did the install in my driveway and yes, I used a signifcant amount of tools! Swivels, extensions, every length 14mm socket available and several different open end and ratcheting wrenches. Admittedly, I have a tool box that would rival a master mechanic, so tools are never a concern, but I was a little surprised at how many different ones I used.

The worst part of this install was the AHC... those lines make access to the nuts very, very difficult and hard to get your hands anywhere close. For that reason alone, I dont think I would recoomend doing this job on an LX, unless your exahust leak was very, very bad. There just isn't enough preformance improvment to make it worth while. It took me 9 hours to do this job start ot finish, with 20 minutes for lunch. I had zero problems breaking any of the nuts loose, nothing stripped or was otherwise problematic and I resused the factory exhaust manifold gaskets as they looked to be in great condition after hitting them with a little brake cleaner.

Now, on a Land Cruiser or a rig with its AHC removed, then that is a different story, I would probably have completed the job in 4-6 hours and felt that the effort was worth the outcome. Honeslty, the dreaded driver side isnt that bad at all... I did jack up the engine 1-2 inches and disconnected the steerring shaft, but removal of the old manifold was pretty easy... getting the header on was a different story. With the AHC lines and the tight bends of the tubing, a couple of the nuts were nrealy impossible to reinstall... I finally figured out that you have to drop the engine back down to slide your arm up past the CV to tighten those lower nuts... even then, you cant see them, its all by feel... and torque values?? :lol: DOnt worry about torquing these things down... there is no way you could ever get a torque wrench on most if any of the nuts, even if the engine was out of the rig.. so I just did my best to tighten things down and happy that after all was said and done, no leaks.

To sum up... would I do this job again? ... definately on an LC without AHC.. its not a bad job on a clean, rust free vehicle, probalby a little tougher and frustrateing if you a breaking off studs etc... but on an LX? I would think more than twice if its just a performance upgrade because I really dont think there is enough improvement to warrant all the work. The engine feels a bit smoother in all RPM's but I dont feel like I have gained any noticable power... On an LC, even if I was dreaming that my manifolds were leaking, I would do this job.. on an LX, it would have to be such a bad leak that I had other concerns, like exhaust getting into the cabin before I would do it again.

That is my feedback after completing my header install. If anyone would like more detail or tips and tricks, please post or PM me, I'll be happy to give you as much info as possible.
 
I finished installing the DT Headers last thursday. I'm the third owner of a CA truck with 168k on it. It had significant ticking from the drivers side. (I installed the PS headers first and didn't notice any difference in the ticking). Plus my rig is getting heavy and running 295s. So I could use all the extra power I could get. I'm hoping the headers help at higher elevation where my last 100 struggled to breathe.

No bolts backed out. Used new OEM gaskets, flange and nuts. I bought new studs but didn't have to use any. And new Denso O2 sensors.

PS took 2 hours. DS took 4 hours. Pretty fast but I think I just got lucky. It's nice to have a CA truck for a change.

I use an X-Beam flexible head 14mm gear wrench, a 2" deep socket 14mm socket. Between the 2, I was able to reach almost all the bolts. I used an extension a few times.

I'm having trouble getting the lower nut tight on the DS 2nd cylinder from the front. The DT's make it even harder to get to the nuts than the OEM headers. I could get a wrench on it but only turn it a fraction of a turn at a time. It was getting dark so I gave up on that one bolt and will attack it again in a few days. No leaks that I can tell because the other 8 bolts on that side are tight.

Noticeably quicker. It feels like I'm running stock tires again.

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I didn't think to remove the steering linkage but that would have helped a lot. I lifted up the engine a lot, 2-3 inches. It took me a few bolts before I realized which engine mount bolts were the two that need to be removed in order to lift the engine. I jacked the engine up from the lowest metal point,which is where it jons the transmission.
 
I have a "ticking" sound as well.
My mechanic told me that there is a small crack in the OEM header but it was closed when the engine is hot.
Maybe the crack is getting bigger.
 
It would be awesome if someone could get empirical numbers. There are and I have some OBD software tools that could measure for example, time elapsed to get from 0-60, 1/4, or computed hp or tq. Just pick your favorite stretch of road.

Now if only someone would buy me a set of headers. :)
 
It would be awesome if someone could get empirical numbers. There are and I have some OBD software tools that could measure for example, time elapsed to get from 0-60, 1/4, or computed hp or tq. Just pick your favorite stretch of road.

Now if only someone would buy me a set of headers. :)

Rob red has done that.

I think the important part of this thread is that DT headers is a $600 modification you can do yourself. Not a mod that requires an additional $500 for professional installation.

They're easier to install than the write ups imply and it's about a :banana::banana: job and can be done with just hand tools on a saturday afternoon, if your truck is relatively rust free. It's one of the best mods I've done for $500. And it's a mod that you get to take advantage of every day, not just off road.
 
I think he's asking for real world before/after numbers vs the dyno. Valid point. If 30 hp nets only 0.2 sec 0-60 then not much was gained. Maybe RR has this too and I missed it... Was thinking it was just dyno curves.
 
Anyone have any MPG numbers? I would think that opening up the exhaust to allow the engine to breathe better would also improve the mileage some. Any before / after MPG numbers would be interesting to see.
 
I wasn't aware of the dyno results from Robred. Thanks for pointing it out, and thanks Robred for doing that work! Those are pretty solid gains and the bang for buck is definitely there.

Now if I could only find some vvti motor results...
 
I think he's asking for real world before/after numbers vs the dyno. Valid point. If 30 hp nets only 0.2 sec 0-60 then not much was gained. Maybe RR has this too and I missed it... Was thinking it was just dyno curves.

Never bothered with measuring ETs. I have done both standing start and rolling drag races with a stock LC and the DT equipped pulls the stocker.

In my mind the driveability is more important then stats - the headers improve that.
 
Normal seat of the pants gains aren't to be trusted. But when they're backed up with dyno results that would indicate enough of a gain to feel it in your butt...

Theoretically, mpg would improve. But most people have reported either a negligible gain or a decrease because they drive it harder now.

I have no facts to support this but I bet that any mpg gains would be so slight as to be unmemorable outside of a controlled environment. There is a probably a mathematical way to calculate this. But it would only make sense if the headers allowed you to use less gas to create the same horsepower. For example, maybe you could cruise at 65mph on a flat road at TPS setting 15 instead of 16 after the header install.
 
I have the benefit of two of the exact same vehicles at home... both 2000 LX470's, both with similar miles.. around 100k, ( they are even the same color)... and both equiped the same...

My LX with the headers does have a bit better driveability... its a little peppier.. so it feels better to drive... no idea of any mileage changes yet, just dont have enough miles on the headers...
 
Having just completed my DT header install a couple hours ago, I thought I'd extend this thread with some of my perspective:

From start to finish, this job took me about 10 hours. PS was 3.5 hours and DS was 6.5. Other than a frozen O2 sensor, I had no problems with frozen/rusty parts. All of the exhaust components broke loose fairly easily. As stated before, some of the exhaust nuts/studs are in precarious places, especially the DS on the new headers. The tool I found indispensable was a VERY low profile stubby box wrench and a similar gear wrench. You'll go through a lot of combinations of 14 mm, but there were two nuts (bottom aft on the DS) that I couldn't get anything on except for the low profile stubby box wrench.

I jacked the motor up on the DS about 1.5 inches. This prevented have to remove the steering linkage. The heat shield on the DS side had to wait to come out with the exhaust manifold.

The motor mount on the DS has ONE of the nuts welded to it. I wasted an hour and ruined a universal trying to remove it before I tried it from the top and the bolt came loose.

My LC had a bad tick and I was convinced that I would find a failure in the OEM header once removed. To my surprise, they were in great shape; no cracks, holes, or anything that looked remotely compromised. This was true for the gasket as well. Because of this I decided to use the DT supplied gasket instead of the OEM one that I had on hand. Once reassembled and optested for 50 miles, all previous ticking was gone and the engine is really quiet.

That's it. It was a lot of tight work, but it is very doable for the budding DIYer.

Hope this helps someone.

greg
 
I have a 2000 LX with 130k and the notorious tick from both sides for about 3-4 min before it warms up. Am I off base to think it would be easier at 190k when I need a new timing belt to just yank the engine? Once it's out I could do the manifolds (ten hour job in 1 hour id think) timing belt and water pump, throw in new motor mounts, replace all the hoses on the engine while its out, throw in a new starter, new bushings on the steering rack, ect.
 
Resurrecting this thread, cuz it's relevant. I'm still looking for my 100 series and I've been looking a lot at the LXs. (I have read a lot about AHC and I think I know I'm getting into there.) I understand the exhaust manifolds are a weak point on these engines. I've read RobRed's threads on DT headers as well as the cat back exhaust performance. (Awesome bit of work there.) Based on what I've read until this thread, a cracked exhaust manifold sounds like a good excuse to get a performance upgrade.

If I end up with an LX, I plan on keeping the AHC system. It seems the DT headers fit with the AHC in place. Are the parts for a 98-05 Land Cruisers the same for LXs? I went onto the Doug Thorley site and they don't list any products for the Land Cruiser. Anyone know what's up that?

According to the OP, the installation of these headers on an AHC equipped LC/LX is inconvenient enough to make the OP think twice about doing it again. But what about where this thread left off, the last post:

I have a 2000 LX with 130k and the notorious tick from both sides for about 3-4 min before it warms up. Am I off base to think it would be easier at 190k when I need a new timing belt to just yank the engine? Once it's out I could do the manifolds (ten hour job in 1 hour id think) timing belt and water pump, throw in new motor mounts, replace all the hoses on the engine while its out, throw in a new starter, new bushings on the steering rack, ect.

Is there anything particularly annoying about pulling the engine in the 100 series that would make it a bad idea for doing the manifold for a header swap as well as take care of other hard to reach maintenance items?
 
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