Headers for V8 cars, Please read
As soon as I see some numbers I am in!
Instructor
Joined: Jun 2001
Posts: 1,135
Likes: 1
From: Seattle
I am about to initiate a project here after doing some research that I had no time for before, and could use some flanges, had planned on just hogging some out with a torch, or waterjet even.
Let us know if you could sell the flanges separately, I for one, may be interested.
Let us know if you could sell the flanges separately, I for one, may be interested.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Show Time!
First of all lets review the stock passenger side 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.
First of all lets review the stock passenger side 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.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Now, look at the prototype.
Each runner exits smoothly and directs the exhaust energy towards the catalyst inlet. Notice how the front 2 runners join in a nice merge collector, same happens with the rear 2 runners. This manifold will flow much better at ALL RPMs.
Each runner exits smoothly and directs the exhaust energy towards the catalyst inlet. Notice how the front 2 runners join in a nice merge collector, same happens with the rear 2 runners. This manifold will flow much better at ALL RPMs.
Lead Lap
Joined: Nov 2004
Posts: 441
Likes: 0
From: Alberta
My previous discussion in another thread;
Now someone who agree's with me.
Honestly, the stock design looks like ****, even neon's and honda stock manifolds are nicer than this even. No offence to "Bruce", but I do not agree with him at all.
Originally Posted by Hollywood
But there must be so much power lost in the headers. DaveGS4 says there is only like 2 hp gained from swapping a cat back exhaust??? It really should be that way unless the cats are mega restrictive or the headers are so bad that you cant even see gains from a performance cat back.
Put it this way if you can make gains with replacing the intake (which I have read in these forums), and not from the exhaust then there is somthing seriously holding back the power between the exhaust side of the heads to y pipe. Judging by the pics I have seen in the big header thread, it looks like the headers are the culprit.
Put it this way if you can make gains with replacing the intake (which I have read in these forums), and not from the exhaust then there is somthing seriously holding back the power between the exhaust side of the heads to y pipe. Judging by the pics I have seen in the big header thread, it looks like the headers are the culprit.
Originally Posted by RMMGS4
That is a good assumption, however if the design of intake , exhaust and header was already designed well from the factory, then your theory could be wrong. Also depending on who's post you read, the change in intake AND exhaust does yield an overall improvement. Too many people do exhaust first and don't do the intake as well, then they give credit to the intake when they add it later, as if the exhaust didn't contribute. The science of providing good breathing and exhaust doesn't really change here.
I discussed this exact question with Bruce Nomura and he said the factory header design was not that bad. He felt the installation of well designed headers can yield some improvement, but not as significant as one would think.
I discussed this exact question with Bruce Nomura and he said the factory header design was not that bad. He felt the installation of well designed headers can yield some improvement, but not as significant as one would think.
Originally Posted by jbrady
Show Time!
First of all lets review the stock passenger side 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.
First of all lets review the stock passenger side 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.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Originally Posted by Hollywood
Honestly, the stock design looks like ****, even neon's and honda stock manifolds are nicer than this even. No offence to "Bruce", but I do not agree with him at all.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Originally Posted by lex400pshR
Any pix of the drivers side header?
When is the estimated time to actually have these ready for sale?
When is the estimated time to actually have these ready for sale?
I will be sending this back to be completed for pre-production. If the fabricator will go ahead and build the driver side pre production part we should hope to have these available in 30-60 days.
Lead Lap
Joined: Nov 2004
Posts: 441
Likes: 0
From: Alberta
Originally Posted by jbrady
No pics because it hasnt been built yet.
I will be sending this back to be completed for pre-production. If the fabricator will go ahead and build the driver side pre production part we should hope to have these available in 30-60 days.
I will be sending this back to be completed for pre-production. If the fabricator will go ahead and build the driver side pre production part we should hope to have these available in 30-60 days.
Driver
Joined: Jan 2005
Posts: 173
Likes: 0
wow! this sounds pretty exciting and if the cost is what it was originally estimated at I will be in on these babies..........that is if people dyno them with anything over 10-15whp gains.
The stock design obviously had flaws and the aftermarket one looked MUCH better.
Ok well here is what I will need before I decide to do this (when they are available)
1) some responses as to how loud it is over the stockers.
2) ease of install.
3) ability to pass a regular smog check
4) performance #s with a dyno sheet
5) exact price figure
otherwise they sound like they are great
The stock design obviously had flaws and the aftermarket one looked MUCH better.
Ok well here is what I will need before I decide to do this (when they are available)
1) some responses as to how loud it is over the stockers.
2) ease of install.
3) ability to pass a regular smog check
4) performance #s with a dyno sheet
5) exact price figure
otherwise they sound like they are great
Lexus Champion
Joined: Sep 2004
Posts: 2,313
Likes: 4
From: NorCal
Better that stock manifold.
Originally Posted by jbrady
Now, look at the prototype.
Each runner exits smoothly and directs the exhaust energy towards the catalyst inlet. Notice how the front 2 runners join in a nice merge collector, same happens with the rear 2 runners. This manifold will flow much better at ALL RPMs.
Each runner exits smoothly and directs the exhaust energy towards the catalyst inlet. Notice how the front 2 runners join in a nice merge collector, same happens with the rear 2 runners. This manifold will flow much better at ALL RPMs.
Will
Lexus Fanatic
Joined: Dec 2003
Posts: 14,523
Likes: 3
From: new jersey
i would also like to know how loud will these be
they look great ...and comparing old to new ..i can see the great improvement
for $600 they seem very affordable
any clue on degree of diffuculty on remving and installing ??
they look great ...and comparing old to new ..i can see the great improvement
for $600 they seem very affordable
any clue on degree of diffuculty on remving and installing ??
Cant wait!
Guys,
I am very interested but a little confused. If someone could answer these questions I would greatly appreciate it. They will be going on a 95 Sc400.
1. Approximate labor time including reworking for the SC400?
2. The write-up says this about the 95 SC400 - No EGR provisions will be made so the installer will need to consider this if they choose to retain EGR.
What exactly does this mean? Oklahoma does not have inspections so I don't have to worry about that - but will this not mean I will have a CEL on all the time?
Thx,
Jonny
I am very interested but a little confused. If someone could answer these questions I would greatly appreciate it. They will be going on a 95 Sc400.
1. Approximate labor time including reworking for the SC400?
2. The write-up says this about the 95 SC400 - No EGR provisions will be made so the installer will need to consider this if they choose to retain EGR.
What exactly does this mean? Oklahoma does not have inspections so I don't have to worry about that - but will this not mean I will have a CEL on all the time?
Thx,
Jonny