New Headers for the 1UZFE

The 1UZFE EGR Delete Kit is available for sale here.

JBrady

Active Member
Messages
1,776
Location
Houston Texas
Well over a year ago I began the process of having headers built for the 1998-2000 GS400. Here is the GP link here on Lextreme
http://www.lextreme.com/forums/showthread.php?t=474&page=1&pp=20

Shortly after that Club Lexus approved my offer and I posted there as well.
http://www.clublexus.com/forums/showthread.php?s=&threadid=102725

Lextreme generated about 15 firm commitments (of 20 needed) mostly SC400s and Club Lexus generated around 40 commitments mostly GS400s. Several of these people pitched in and sent donations so that I could purchase a set of stock manifolds (hard to find and expensive) to send to the fabricator. I answered many many many questions, emails and private messages on both boards and ended up keeping the updates on Club Lexus due to the larger number of commitments there.

Long story short the fabricator hasn't worked on the project. Read the last posts on CL for the update.

FINALLY... he built a prototype passenger side and shipped it to me for inspection. I will have it tomorrow evening and will take pictures and post updates on CL and here.

Things are moving forward!

Stay tuned.
 
FINALLY...

Here is the prototype passenger side manifold. Notice the nice merge collector shape for the front 2 runners and then again with the rear 2 runners.
 
Compare to the stock manifold (which is a 1998-2000 GS400 and is BETTER than the early 1UZFE manifold). Look at the HORRIBLE 90 degree intersection the both of the back 2 ports dump into. There is virtually no runner length and the construction is appaling in that the runners overlap the downstream pipe leaving a sharp inside edge on top of the 90 degree turn and no runner length. The front tube is the only one on this manifold that has any use. The second from the front enters the front tube again at 90 degrees and with the same internal sharp edge. Score, 3 bad ports and one decent port.
 
JBrady, are you staying with the original mild steel, ceramic coated philosophy? You're probably aware of Boostlogic over in Austin, who are making some very nice Supra (turbo) manifolds and have had excellent results with 321SS. The majority of their manifolds are only two years old, but there's a fair population of them in circulation now, and there hasn't been a single report of cracking AFAIK, whereas the HK$ manifolds were prone to cracking at the collectors after only a year to 18 months. Any chance of making these things in 321SS?

John
 
cribbj said:
JBrady, are you staying with the original mild steel, ceramic coated philosophy? You're probably aware of Boostlogic over in Austin, who are making some very nice Supra (turbo) manifolds and have had excellent results with 321SS. The majority of their manifolds are only two years old, but there's a fair population of them in circulation now, and there hasn't been a single report of cracking AFAIK, whereas the HK$ manifolds were prone to cracking at the collectors after only a year to 18 months. Any chance of making these things in 321SS?
John

John,
Of course it would be very nice to have 321SS headers. For those that are unaware standared aftermarket stainless parts are 304 series stainless that is very nice but not as nice as the even nicer 321 series. Go to www.burnsstainless.com if you want a full education.

The problem is one of cost. I do not know but based on their kit pricing it would apear that the manifold itself would probably sell for $1800-2000. For the 2 required for the 1UZFE we are talking in the $2500-3000 range. While very nice and one of the best choices (inconel being the number one choice but double the price)... most people would not spend that much for headers. A pair of 304SS manifolds in the low production that we anticipate for this application would probably be in the $1000-1500 range. Now if there is enough demand and they can be made in China then the price could go down dramatically BUT for now, under the circumstances, ceramic coated mild steel headers at $600 is affordable and marketable and if all goes well ACTUALLY available.
 
barwick said:
A quick question guys... does the tundra headers fit straight into 1UZFE or are modifications required

The Tundra headers will not fit any of the Lexus/Toyota sedans. Chrisman used modified ones to direct the exhaust forward to turbos but removed the A/C to do that. Major surgery may be possible but by that time you are as invested as building new ones. Plus, the Tundra headers use 1.625" tubing which is too large even for the 4.7 liter 2UZFE let alone the 4 liter 1UZFE. People almost always think bigger is better but this is definitely NOT the case with exhaust. You want the smallest pipe that will support your power needs. This gives the best torque curve, performance, drivability and gas mileage.
 
JBrady:

How would you think 1 5/8" tubing with 1/8" walls would do on a stock set up, and then on a turbo project? How well do you think ceramic coated (inside and out) mild steel will hold up due to heat on the turbo application?

Ryan


JBrady said:
The Tundra headers will not fit any of the Lexus/Toyota sedans. Chrisman used modified ones to direct the exhaust forward to turbos but removed the A/C to do that. Major surgery may be possible but by that time you are as invested as building new ones. Plus, the Tundra headers use 1.625" tubing which is too large even for the 4.7 liter 2UZFE let alone the 4 liter 1UZFE. People almost always think bigger is better but this is definitely NOT the case with exhaust. You want the smallest pipe that will support your power needs. This gives the best torque curve, performance, drivability and gas mileage.
 
The next question is how are these better than the "Tex" headers?

For a hijack type of question id like to ask what the best length would be for long tubes on a stock motor?

Im not trying to bust anyones balls, and I know its a limited market, etc, and I will probably buy these or tex's headers.
Thanks,
Josh
 
SC400T said:
JBrady:

How would you think 1 5/8" tubing with 1/8" walls would do on a stock set up, and then on a turbo project? How well do you think ceramic coated (inside and out) mild steel will hold up due to heat on the turbo application?

Ryan

The coated headers should survive reasonably well in a turbo environment providing the EGTs and the fuel ratios are kept in check. For street driven vehicles boosted operation is only a small percentage of drive time so this shouldnt be a problem.

1/8" tubing is not an option, sorry.

1.625" pipes (1 5/8") are not needed and will cost low RPM response and torque.

Butler performance Group built a twin turbo 482 cid Pontiac, nearly 8 liter engine (nearly double the displacement of a 1UZFE) and it had 2" primary pipes with 2.5" collectors. This engine did not seem restricted when you consider that at 7200rpm it dyno'd at 2,886 horsepower and 2,105 torque. 7200rpm was also the LOWEST rpm that the dyno could hold the torque... it was higher at lower RPM but the dyno couldn't hold it to measure it. So, on a turbo engine, one that you hope to get best turbo response from, I would suggest the 1.5" pipes to be fine, even desirable over larger ones.
 
sloshua said:
The next question is how are these better than the "Tex" headers?

For a hijack type of question id like to ask what the best length would be for long tubes on a stock motor?

Im not trying to bust anyones balls, and I know its a limited market, etc, and I will probably buy these or tex's headers.
Thanks,
Josh

While better than stock for peak power the "Tex" headers from responses I have heard cost low RPM torque and response. These shorty headers should help at all RPMs. Ideal length of primary tubes depends on 4 into 1 or tri-y configuration. Some argue that with a secondary exhaust system (such is the case with street cars) that the tuning signal is changed and the real world difference between a manifold with good "flow" characteristics and a long tube "tuned" manifold to be very small. In fact without good collector design the shorty may outperform the long tube altogether.

We shall see once these can be tested but considering the stock manifold design is there really a question of need?
 

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I'm still in

I was one of the members who comitted to the group buy way back when. I have a different first gen LS now but i still need the same headers.

JBrady, do you have any information on what work it will take to physically get these headers into our cars. getting some bends with flanges and slight cat relocation are givens, it would be nice to know an estimated cost of just the fitment. someone mentioned that the official lexux service manual said you needed to drop the trans on the SC to replace the stock 'tube' but people have fit the tex headers in without doing so. Any info on what it takes to fit them into the various models might attract more interest in the project.

P.S. My father plans to purchase a LS430. when i showed him the exhaust diagram of the LS400, his response was 'what a waste of a V8'. He wants to eventually redo the entire exhaust. If there is a possibility of fitment on the 4.3 litre please put me down for another set!

Thanks for spearheading this venture
 
I couldn't say I lost any torque down low with the long tube headers. I can't think of anyone saying they did lose torque anywhere in the rev range with Tex's headers. In fact I reckon people reckon the headers improve torque down low and give the car more punch of the line. I can't think of anyone saying the long tube headers lost torque for them down low.

extractorpipessmall.jpg

15275.gif
 
Yeah, usually it's smoother everywhere, and the increase in top end makes the car feel slower at low revs compared to stock, when you actually have improved there too, just not as much as when things really get moving.
 
DonyLingus said:
I was one of the members who comitted to the group buy way back when. I have a different first gen LS now but i still need the same headers.

JBrady, do you have any information on what work it will take to physically get these headers into our cars. getting some bends with flanges and slight cat relocation are givens, it would be nice to know an estimated cost of just the fitment. someone mentioned that the official lexux service manual said you needed to drop the trans on the SC to replace the stock 'tube' but people have fit the tex headers in without doing so. Any info on what it takes to fit them into the various models might attract more interest in the project.

P.S. My father plans to purchase a LS430. when i showed him the exhaust diagram of the LS400, his response was 'what a waste of a V8'. He wants to eventually redo the entire exhaust. If there is a possibility of fitment on the 4.3 litre please put me down for another set!

Thanks for spearheading this venture

I really cannot answer your question. Maybe some of the SC owners who have added the Tex headers can help here. The main problem on the cars with the dual tube headers is just getting the heat shields off. You cannot access the header bolts with the heat shields in place. On the earlier engines this does not seem to be a problem. I also expect an easier time with the 4.3 liter cars as Lexus went back to a single tube design which makes for a smaller heat shield and easier access.

I think fitment on a 4.3 car is very doable with a custom Y pipe.
 
uzz32pete said:
I couldn't say I lost any torque down low with the long tube headers. I can't think of anyone saying they did lose torque anywhere in the rev range with Tex's headers. In fact I reckon people reckon the headers improve torque down low and give the car more punch of the line. I can't think of anyone saying the long tube headers lost torque for them down low.

To everyone reading this thread, I in no way am trying to insult the Tex headers. I am only relating what I heard from questioning one of the SC owners (apx 2 years ago) about the results. I look forward to a comparison between the two designs both of which are compromises.

Pete, that is a very encouraging dyno chart. It lists 2.25" pipes and I thought you had 2.5" pipes... is that a misprint?

The power curve is very interesing. You picked up about 30hp peak and over 45hp at redline (or whatever RPM you stopped at). What was the RPM range? That said your reading of 153kW is roughly 205rwhp. Not bad for a first gen
 
It's not my dyno graph! It's some other guys.
I just picked it out as an example of before and after. I've got a few before and after dynos with the headers.
In almost every case more torque appears to be the case. Sometimes it is the same down low with only gains up top. I was interested where you got your "less torque" case from because I haven't seen it happen yet.

I don't quote peak power too often from a single dyno run. Some guys over here have got 170 odd rwkW at the wheels with headers, intake and Unichip tune. I got 164 rwkW before Unichip at one dyno place and 142 rwkW a month later on a different dyno with the same tune! Currently with the Unichip I'm running 158 rwkW. There is a dyno day library for 1UZ-FE's here:
http://planetsoarer.com/dynolibrary/dynolibrary.htm

Some guys tell me that US and UK dynos have higher reading than Dyno Dynamics - so it's a bit hard to compare car to car. Most times we get valuable info from dyno days where we run a bunch of Soarers together.

I think the shorty headers you are getting developed are a great idea I really do. When I wanted headers years ago there was only one choice - Tex's or custom made. Tex's are still the only over the counter headers I know of - but they don't fit smog cars in the US without further mods.

Shorty headers have advantages for smog legal car with cats being in the same postion etc - and I reckon they will give great gains over the stock headers for sure. I congratulate you for your efforts in getting them done that's for sure. There just aren't enough choices when it comes to headers for the 1UZ-FE.

Shorty headers, long tube headers, if we had a Mustang then we could choose anything we wanted!! But for our car it's a pain getting hot up parts to say the least.

Here's another dyno comparison of a 2L 4 cylinder (half a 1UZ-FE?) with shorty headers, 4-2-1 headers (like Tex's headers) and 4-1 headers. The 4-2-1 headers beat them all in this case.
dynochart.jpg


Dyno charts are really only good for full load, full throttle information. Part throttle, part load - all this stuff is shown on the dyno.

Good luck with the project and the headers - sounds like it has been real hard work.
 


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