Headers for V8 cars, Please read
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
BTW, the GM LS6 I mention above is a 2 valve/cyl head, single cam, push rod design that makes 96% as much power per liter at the same RPM and compression ratio as our high tech 4 valve/cyl, dual overhead cam engines. The LS6 has GOOD factory exhaust manifolds and typically picks up 20-30rwhp with headers. With ported heads, headers and larger cams MANY of these engines are making over 450rwhp (530hp crankshaft using a conservative 15% drivetrain loss) up from a stock 345rwhp.
Oh, and too rub salt in the wound, the 2002-2004 Corvette that this LS6 came in is rated at 19mpg city and 28mpg highway
Oh, and too rub salt in the wound, the 2002-2004 Corvette that this LS6 came in is rated at 19mpg city and 28mpg highway
JBRADY 
Pole Position
Joined: Jan 2004
Posts: 374
Likes: 0
From: Florida
jbrady...how many 430 committed people r there?
also when u start going into details its is all Greek to me so can u tell me from your best guesstimates does $1500 to $2000 seem accurate for the entire project? i'd like ur opinion on this...thanks!
also when u start going into details its is all Greek to me so can u tell me from your best guesstimates does $1500 to $2000 seem accurate for the entire project? i'd like ur opinion on this...thanks!
Lexus Test Driver
Joined: Dec 2002
Posts: 1,159
Likes: 0
From: California
Hi I would like to know the ETA on this project, and if it is bolt on for the 400? i know its in the thread but its 30 pages long and not really up to reading. Thanks. Depending on the ETA you will have my full commitment.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Originally Posted by NoRyceGS4
Hi I would like to know the ETA on this project, and if it is bolt on for the 400? i know its in the thread but its 30 pages long and not really up to reading. Thanks. Depending on the ETA you will have my full commitment.
ETA: 6-8 weeks.
BTW, I spoke with the manufacture Monday and this is our current status. All committed people were notified by email of our status and plans. If anyone reading this did NOT recieve an email and you believe you should have please PM me. Again, ONLY COMMITTED people who are on my list of purchasers would have recieved the email.
EV ftw!!!
Joined: Nov 2002
Posts: 8,947
Likes: 546
From: Lake Ontario
Originally Posted by jbrady
I took no offense to Fishers post. Even though the info is in this LONG thread I thought it time for a quick refresher and hence the answers to the questions.
Regarding 20rwhp being worth the trouble. I guess that depends on each individuals personality. Another way to look at it would be, lets imagine the factory built the GS400 with headers like the ones we are planning. Lets further imagine that the engine was rated 325hp instead of 300hp (about 20rwhp difference) and the car was 3 tenths of a second quicker 0-60 and in the 1/4 mile. Lets consider that JUST before the cars where sold Lexus decided to place restrictors in the exhaust to reduce power by 25hp... for "insurance" reasons.... How many of us would PAY to remove those restrictors? Do I see a whole bunch of raised hands?
Well, imagine no more because that is ALMOST what Lexus did. Look at the manifolds on almost ANY other performance engined car and you will see MUCH better manifolds. Lexus must have wanted to restrict this engine. Heck, 6350rpm redline is NOTHING for a small displacement oversquare 4 liter engine with 6 bolt mains and a forged crank. The undersquare GM LS6 makes 405hp at 6000rpm with 10.5 compression. Our 1UZFE and 3UZFEs can easily run 7000rpm. Our valve lift is a paltry 0.300" and duration is nil. A little more cam, good exhaust and 7000rpm would make 400hp a realistic potential. Our intake manifolds are GREAT. Lexus may indeed have found these engines TOO powerful and actually detuned them with among other things LOUSY exhaust manifolds.
Regarding 20rwhp being worth the trouble. I guess that depends on each individuals personality. Another way to look at it would be, lets imagine the factory built the GS400 with headers like the ones we are planning. Lets further imagine that the engine was rated 325hp instead of 300hp (about 20rwhp difference) and the car was 3 tenths of a second quicker 0-60 and in the 1/4 mile. Lets consider that JUST before the cars where sold Lexus decided to place restrictors in the exhaust to reduce power by 25hp... for "insurance" reasons.... How many of us would PAY to remove those restrictors? Do I see a whole bunch of raised hands?
Well, imagine no more because that is ALMOST what Lexus did. Look at the manifolds on almost ANY other performance engined car and you will see MUCH better manifolds. Lexus must have wanted to restrict this engine. Heck, 6350rpm redline is NOTHING for a small displacement oversquare 4 liter engine with 6 bolt mains and a forged crank. The undersquare GM LS6 makes 405hp at 6000rpm with 10.5 compression. Our 1UZFE and 3UZFEs can easily run 7000rpm. Our valve lift is a paltry 0.300" and duration is nil. A little more cam, good exhaust and 7000rpm would make 400hp a realistic potential. Our intake manifolds are GREAT. Lexus may indeed have found these engines TOO powerful and actually detuned them with among other things LOUSY exhaust manifolds.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
I just recieved a PM regarding whether or not headers would be recommended on a supercharged engine. The answer is YES. Here was my response.
While it is actually very complicated let me give you a simplistic explanation. The supercharger will force more air into the cylinders, this greater air combined with greater fuel will create more energy pushing the pistons down and creating more power. This process creates more exhaust gas that must be removed from the cylinder to allow the process to begin again. The stock manifolds are restricting the stock exhaust flow needs. Obviously adding more exhaust demands will make this even worse. Supercharged engines will respond even better to higher flow exhaust than non-supercharged engines... period.
While it is actually very complicated let me give you a simplistic explanation. The supercharger will force more air into the cylinders, this greater air combined with greater fuel will create more energy pushing the pistons down and creating more power. This process creates more exhaust gas that must be removed from the cylinder to allow the process to begin again. The stock manifolds are restricting the stock exhaust flow needs. Obviously adding more exhaust demands will make this even worse. Supercharged engines will respond even better to higher flow exhaust than non-supercharged engines... period.
Lead Lap
Joined: Mar 2004
Posts: 503
Likes: 0
From: New York
JPI I just got off the phone with you about the 90K on the 2001 GS430. Please put me first on the list . I want one of the first set. Are you gonna do hi flow cats? Also JPI maybe you should start a separate thread from Brady's , esecially since your's are going to bolt right on to a GS430. Also pics as soon as you get any progress. 430 Guys her we go......... 
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Originally Posted by JPI
We are in the process of doing the headers ... If you guys interested let us know. We are interested on the performance and not the way it look. Thankz guys.
JP Importz
JP Importz
That said I carefully went through the proper CL channels before starting this process "way back when". Notice that this post was NOT started by me but by Moderator DaveGS4. While it is possible that JP can and will build 430 headers (I certainly do not have a patent or monopoly here) I did check out their website and found no high performance parts offered other than an alternator. I do not know what design and fabrication facilities or experience they have. Have they ever built a header?
Producing production parts is no small task. This project has taken a TON of my time and I do so merely to help the cause. I suggest that before JP attempts to hijack this thread that he take the time to make a thorough write up of just WHAT he intends to offer and HOW he intends to offer it. Unless he is pre-approved he should also proceed through the proper CL channels.
Now, let's assume that all that happens. Lets assume that JP builds and provides a quality part... GREAT. That would be fine by me. But, if for some reason he does NOT... what happens to prospective 430 owners that get distracted and miss getting the headers this thread is devoted to?
Before anything else happens I hope this advice is taken.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Originally Posted by Fisher503
JPI I just got off the phone with you about the 90K on the 2001 GS430. Please put me first on the list . I want one of the first set. Are you gonna do hi flow cats? Also JPI maybe you should start a separate thread from Brady's , esecially since your's are going to bolt right on to a GS430. Also pics as soon as you get any progress. 430 Guys her we go.........
Also, highflow cats are not the issue. The reason for a custom Y pipe would be slightly larger tubing and fitment. The cats (at least the 3rd and possibly #1 and 2) are integral and welded in place. Changing cats defeats the benefits of the above plan.
Lexus Champion
Joined: Jun 2003
Posts: 2,079
Likes: 2
From: Texas
Originally Posted by jbrady
Fisher, I understand your excitement for a direct bolt on part. I also appreciate suggesting a new thread. Please read my above post for additional considerations.
Also, highflow cats are not the issue. The reason for a custom Y pipe would be slightly larger tubing and fitment. The cats (at least the 3rd and possibly #1 and 2) are integral and welded in place. Changing cats defeats the benefits of the above plan.
Also, highflow cats are not the issue. The reason for a custom Y pipe would be slightly larger tubing and fitment. The cats (at least the 3rd and possibly #1 and 2) are integral and welded in place. Changing cats defeats the benefits of the above plan.
It's still in the R&D process. We respect other's people work and won't step on anyone's toe. Our post will end here!
JP Importz
Last edited by JPI Racing; May 27, 2005 at 01:03 PM.
I'm not sure if this is a new idea or not, but, I hope it is and I hope we find the right person!
One way to find out if they'll bolt on to the 430 that isn't *toooo* much work, would be to drop the Y pipe and measure the distance between the pipes. Any one of us that gets the headers for the GS400 can do the same.
If both parties report back with their measurements, we'd know about fitment without anyone having to actually go to the trouble of *mounting* the header on a 430. Am I making any sense here? I hope so.....but it's late....
How great would it be to measure a REPLACEMENT Y pipe from a Lexus shop?!!!?
If ANYONE is in the Dayton Ohio area, and has a GS430, maybe we can get together and drop the Y pipe on the 430. I'd be more than glad to help, and provide the garage if needed.
One way to find out if they'll bolt on to the 430 that isn't *toooo* much work, would be to drop the Y pipe and measure the distance between the pipes. Any one of us that gets the headers for the GS400 can do the same.
If both parties report back with their measurements, we'd know about fitment without anyone having to actually go to the trouble of *mounting* the header on a 430. Am I making any sense here? I hope so.....but it's late....
How great would it be to measure a REPLACEMENT Y pipe from a Lexus shop?!!!?
If ANYONE is in the Dayton Ohio area, and has a GS430, maybe we can get together and drop the Y pipe on the 430. I'd be more than glad to help, and provide the garage if needed.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
I would not trust a measurement. Actually test fitting is the way to know.
I just reviewed the technical pages for the GS430, LS430 and SC430 and it LOOKS like Lexus used the SAME Y pipe, cats and headers on all three vehicles. This is good news. The Y pipe does not have the front 2 cats attached only the 3rd. This makes a 430 Y pipe very reasonable. Maybe a non catalyst Y pipe with room to add a catalysts for those wanting one. Options create additional R&D time and expense. If one pipe can be made and sold that would be ideal. It would be very good to test fit a GS430 Y pipe on a GS400. If it fits that increases the chance that the headers will be a bolt on. The flange style is the same but exact bolt location, spacing and angles will not be known without test fitting.
I just reviewed the technical pages for the GS430, LS430 and SC430 and it LOOKS like Lexus used the SAME Y pipe, cats and headers on all three vehicles. This is good news. The Y pipe does not have the front 2 cats attached only the 3rd. This makes a 430 Y pipe very reasonable. Maybe a non catalyst Y pipe with room to add a catalysts for those wanting one. Options create additional R&D time and expense. If one pipe can be made and sold that would be ideal. It would be very good to test fit a GS430 Y pipe on a GS400. If it fits that increases the chance that the headers will be a bolt on. The flange style is the same but exact bolt location, spacing and angles will not be known without test fitting.
Lead Lap
Joined: Nov 2004
Posts: 441
Likes: 0
From: Alberta
Originally Posted by jbrady
I would not trust a measurement. Actually test fitting is the way to know.
I just reviewed the technical pages for the GS430, LS430 and SC430 and it LOOKS like Lexus used the SAME Y pipe, cats and headers on all three vehicles. This is good news. The Y pipe does not have the front 2 cats attached only the 3rd. This makes a 430 Y pipe very reasonable. Maybe a non catalyst Y pipe with room to add a catalysts for those wanting one. Options create additional R&D time and expense. If one pipe can be made and sold that would be ideal. It would be very good to test fit a GS430 Y pipe on a GS400. If it fits that increases the chance that the headers will be a bolt on. The flange style is the same but exact bolt location, spacing and angles will not be known without test fitting.
I just reviewed the technical pages for the GS430, LS430 and SC430 and it LOOKS like Lexus used the SAME Y pipe, cats and headers on all three vehicles. This is good news. The Y pipe does not have the front 2 cats attached only the 3rd. This makes a 430 Y pipe very reasonable. Maybe a non catalyst Y pipe with room to add a catalysts for those wanting one. Options create additional R&D time and expense. If one pipe can be made and sold that would be ideal. It would be very good to test fit a GS430 Y pipe on a GS400. If it fits that increases the chance that the headers will be a bolt on. The flange style is the same but exact bolt location, spacing and angles will not be known without test fitting.
Cool. Do you have a picture of it? Real or FSM does not matter.