Tex's Headers on US sc400
#16
Lexus Test Driver
Thread Starter
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
Originally posted by VSsc400
Did you relocate the EGR valve?
I don't think you can pass emissions without an EGR valve. It may emit too much Nox gas to pass.
how did you address this issue?
I would love to do it but don't want a vehicle that will not meet emission standards....
Did you relocate the EGR valve?
I don't think you can pass emissions without an EGR valve. It may emit too much Nox gas to pass.
how did you address this issue?
I would love to do it but don't want a vehicle that will not meet emission standards....
#17
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
What shop did you take it to???
I live half the time in Annapolis and the other half of the time where Anne Arundel and Calvert County meet. Not sure how "south" you are when you say south.
I live half the time in Annapolis and the other half of the time where Anne Arundel and Calvert County meet. Not sure how "south" you are when you say south.
#18
Lexus Test Driver
Thread Starter
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
shop i took it to is www.cdemotorsports.com
It's a good shop, clean, and very professional. And they also compete in the 1/4 mile with a f150 (not sure which league though).
If you live in MD, there are a ton of good shops around from what I hear.
It's a good shop, clean, and very professional. And they also compete in the 1/4 mile with a f150 (not sure which league though).
If you live in MD, there are a ton of good shops around from what I hear.
#21
Lexus Test Driver
Thread Starter
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
I hit the track today to get some numbers.
Here are my stock times:
https://www.clublexus.com/forums/sho...threadid=57271
Todays numbers were:
Temp 84 F
R/T: 1.626
60': 2.559
1/4: 15.583
MPH:92.2
I had no traction on this first run. Stalled at 1800 rpm and launched and no traction so that's why the bad time.
Second run:
Temp 84F
R/T: 1.014
60': 2.172
1/4: 15.075
MPH:91.56
Much better launch but still not the best. I still need more practice and I'm sure I can break into the 14's soon.
MODS: PI torque converter, Tex's headers and custom exhaust, and snorkel removed
I also removed the spare tire this time. And yes, I was sleeping at the tree again
Here are my stock times:
https://www.clublexus.com/forums/sho...threadid=57271
Todays numbers were:
Temp 84 F
R/T: 1.626
60': 2.559
1/4: 15.583
MPH:92.2
I had no traction on this first run. Stalled at 1800 rpm and launched and no traction so that's why the bad time.
Second run:
Temp 84F
R/T: 1.014
60': 2.172
1/4: 15.075
MPH:91.56
Much better launch but still not the best. I still need more practice and I'm sure I can break into the 14's soon.
MODS: PI torque converter, Tex's headers and custom exhaust, and snorkel removed
I also removed the spare tire this time. And yes, I was sleeping at the tree again
![Wink](https://www.clublexus.com/forums/images/smilies/wink.gif)
#23
Lexus Test Driver
Thread Starter
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
O/D off
traction off
ECT on
I got my best times with stock TC brake torqueing at 1800.
On last yellow, I lift brake and floor it. I would get a nice little tire chirp but no spin and off I go.
On my crappy tires, I'm still trying to figure out the ideal launch. Brake torquing at anything seems to spin the tires when I release the brake. I need to learn how to control the gas pedal more subtely.
traction off
ECT on
I got my best times with stock TC brake torqueing at 1800.
On last yellow, I lift brake and floor it. I would get a nice little tire chirp but no spin and off I go.
On my crappy tires, I'm still trying to figure out the ideal launch. Brake torquing at anything seems to spin the tires when I release the brake. I need to learn how to control the gas pedal more subtely.
Last edited by verylost; 07-19-03 at 07:44 PM.
#24
Lexus Champion
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
verylost, per your PM request, here are my comments: (others reading this, I am not just critical of everyones cars, as I just stated verylost asked specifically for my imput here):
First of all, what is your impression of power? Long tube headers tend to help low speed torque but with the larger piping (which tends to hurt low speed torque) the effects may be minimal... please post your "seat of the pants" impression. Realize that a louder sounding engine will often FEEL faster and this applies to intakes as well as exhausts. Of course before and after dyno testing is best. Also, peak power numbers are not the important detail. Power under the curve IS. A peaky engine is not near as pleasurable to drive as a torquey engine with a good top end. A "lower" power car will beat a "higher" if the "L" car has more power under the curve. We are not driving fixed RPM engines, transitional response is key.
Let me comment here by saying the workmanship is very nice and the system is sound. I do not think that my comments will prompt you to re-build and already nice system but who knows.
Now, as far as Tex's headers go... much better than the stock manifolds but I am not a fan of the collector design (3 per side) and I also think think, yes, again, the pipe diameter is a bit large. But, without an alternative they are better than stock.
The header outlet size is around 2.5" I believe and that looks like the size continued through the catalysts and the X pipe all the way to the do-luck parts that appear to be more like 75mm apx 3". Again, I would use smaller pipe, 2.25".
The Magnaflow stamped X pipe is better than some but still, too large, too much plenum volume.
So, to design a system from the ground up I would use SLIGHTLY larger than stock header primary pipes. 2.5" catalysts as the velocity with cats is sacrificed anway, go with flow. A long X pipe (basically 2 Y-pipes joined back to back with a foot or more single pipe between them, again 2.25" with either a 2.5" or 3.0" single center pipe (test results sometime in the next couple months). Personally, I plan on using Dynomax superturbo mufflers or Bullet stainless steel turbomufflers in 2.25" sizing to minimize noise while not loosing noticeable power.
So, again, nice work, nice parts. One other comment, you may want to consider relocating the O2 sensors to the header collector instead of the primary tube as the sensor element is taking up a fair amount of each tubes available flow area.
First of all, what is your impression of power? Long tube headers tend to help low speed torque but with the larger piping (which tends to hurt low speed torque) the effects may be minimal... please post your "seat of the pants" impression. Realize that a louder sounding engine will often FEEL faster and this applies to intakes as well as exhausts. Of course before and after dyno testing is best. Also, peak power numbers are not the important detail. Power under the curve IS. A peaky engine is not near as pleasurable to drive as a torquey engine with a good top end. A "lower" power car will beat a "higher" if the "L" car has more power under the curve. We are not driving fixed RPM engines, transitional response is key.
Let me comment here by saying the workmanship is very nice and the system is sound. I do not think that my comments will prompt you to re-build and already nice system but who knows.
Now, as far as Tex's headers go... much better than the stock manifolds but I am not a fan of the collector design (3 per side) and I also think think, yes, again, the pipe diameter is a bit large. But, without an alternative they are better than stock.
The header outlet size is around 2.5" I believe and that looks like the size continued through the catalysts and the X pipe all the way to the do-luck parts that appear to be more like 75mm apx 3". Again, I would use smaller pipe, 2.25".
The Magnaflow stamped X pipe is better than some but still, too large, too much plenum volume.
So, to design a system from the ground up I would use SLIGHTLY larger than stock header primary pipes. 2.5" catalysts as the velocity with cats is sacrificed anway, go with flow. A long X pipe (basically 2 Y-pipes joined back to back with a foot or more single pipe between them, again 2.25" with either a 2.5" or 3.0" single center pipe (test results sometime in the next couple months). Personally, I plan on using Dynomax superturbo mufflers or Bullet stainless steel turbomufflers in 2.25" sizing to minimize noise while not loosing noticeable power.
So, again, nice work, nice parts. One other comment, you may want to consider relocating the O2 sensors to the header collector instead of the primary tube as the sensor element is taking up a fair amount of each tubes available flow area.
#25
Lexus Test Driver
Thread Starter
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
Thanks for the critique.
I really can't tell any "seat of the pants" improvements because im my mind I want there to be an improvement. The one thing I have noticed is that the car seems to jump into the 4k rpm range much easier.
And like VSsc400 stated, I'm saving up my nickel and dimes for FI too
I really can't tell any "seat of the pants" improvements because im my mind I want there to be an improvement. The one thing I have noticed is that the car seems to jump into the 4k rpm range much easier.
And like VSsc400 stated, I'm saving up my nickel and dimes for FI too
![Wink](https://www.clublexus.com/forums/images/smilies/wink.gif)
#26
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
Its nice to see LS400 with time slip. You always hear SC300 with good time. About the R/T. Wake up and leave at the second light. Power brake and rev up to 3000 rpm and let is all out at the second yellow light.
#27
Lexus Test Driver
Thread Starter
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
Reving up to 3000 rpm is too much for my tires. I think my next mod is probably lsd or rims and tires. I figure if i get 9 or 10 wide in the rear, I shouldn't break traction.
#28
Lexus Test Driver
Thread Starter
![Default](https://www.clublexus.com/forums/images/icons/icon1.gif)
jbrady,
after some testing this week, i have definitely lost power on the low end but I have gained in the high end. The butt meter is definitely telling me I'm pulling harder in the 3000+ range and the butt meter is also telling me im having a harder time keeping up with traffic in the lower rpm range.
Ah well, but who drives the 1/4 mile at 2000 rpm anyways?
after some testing this week, i have definitely lost power on the low end but I have gained in the high end. The butt meter is definitely telling me I'm pulling harder in the 3000+ range and the butt meter is also telling me im having a harder time keeping up with traffic in the lower rpm range.
Ah well, but who drives the 1/4 mile at 2000 rpm anyways?
![Wink](https://www.clublexus.com/forums/images/smilies/wink.gif)