Headers for V8 cars, Please read
Lead Lap
Joined: Nov 2004
Posts: 441
Likes: 0
From: Alberta
Originally Posted by jbrady
Thermal wrap would keep underhood temps lower and effectively replace the heat shields. That said thermal wrapping the pipes concentrates a tremendous amount of heat on the metal. It can also hold moisture when the vehicle is not running. Personally I will not be wrapping my exhaust.
REGARDING the heat shields. Yes, the passenger side shield fits BUT at this point no provision has been made for mounting brackets. The shields are attached to the stock manifolds by metal bracket welded to the stock headers. If you look at the stock manifold you can see 3 brackets, one on the 2nd pipe, one near the o2 sensor and one on the back pipe. In order to affix the heat shield we would need to design and locate and build these brackets. This is not an easy task and would increase the cost of the manifolds.
At this point I haven't even discussed this option with the fabricator. Honestly, I am more interested in getting manifolds built than any heat shield issues. The reason he made the header to fit inside the shield was to assure fitment in the vehicle. So, at this point do not expect to be able to use the heat shields. This may become an additional cost option but do not plan on it.
REGARDING the heat shields. Yes, the passenger side shield fits BUT at this point no provision has been made for mounting brackets. The shields are attached to the stock manifolds by metal bracket welded to the stock headers. If you look at the stock manifold you can see 3 brackets, one on the 2nd pipe, one near the o2 sensor and one on the back pipe. In order to affix the heat shield we would need to design and locate and build these brackets. This is not an easy task and would increase the cost of the manifolds.
At this point I haven't even discussed this option with the fabricator. Honestly, I am more interested in getting manifolds built than any heat shield issues. The reason he made the header to fit inside the shield was to assure fitment in the vehicle. So, at this point do not expect to be able to use the heat shields. This may become an additional cost option but do not plan on it.
Originally Posted by NoRyceGS4
if anything just weld the suckers on, would that work? (for the heat shields i mean)
i cant honestly show full interest until i see some real life dyno results.
i cant honestly show full interest until i see some real life dyno results.
There is an easy way to make the heat shields work. You could weld on 2 nuts on the manifold at the high points, drill 2 new holes in the heatshield and screw in 2 new bolts, that way the bolt holes cater to the manifold instead of the original holes on the stock heat shield.
Lexus Test Driver
Joined: Jun 2002
Posts: 869
Likes: 1
From: California
Maybe this has been addressed already, but I'm wondering if an SAFC would be necessary to tune the engine for proper air/fuel ratio with the headers. Or if you have an SRT intake with the ECU would that be able to handle the increased air flow capability of the engine with headers and hi flow exhaust system?
John, do you have any thoughts about the temperature of the engine compartment without the heat shields in place? I know the Jet Hot coating really reduces the temp of the headers too, but I'm wondering if there would still be any issues?
John, do you have any thoughts about the temperature of the engine compartment without the heat shields in place? I know the Jet Hot coating really reduces the temp of the headers too, but I'm wondering if there would still be any issues?
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Originally Posted by FutureGS400
Maybe this has been addressed already, but I'm wondering if an SAFC would be necessary to tune the engine for proper air/fuel ratio with the headers. Or if you have an SRT intake with the ECU would that be able to handle the increased air flow capability of the engine with headers and hi flow exhaust system?
John, do you have any thoughts about the temperature of the engine compartment without the heat shields in place? I know the Jet Hot coating really reduces the temp of the headers too, but I'm wondering if there would still be any issues?
John, do you have any thoughts about the temperature of the engine compartment without the heat shields in place? I know the Jet Hot coating really reduces the temp of the headers too, but I'm wondering if there would still be any issues?
The stock ECU/MAF/injectors/fuel system should have no problem with up to 25% more air mass flow. Mo at SRT suggested (over a year ago on a phone call) that the stock system should support nearly 400hp at the crankshaft. These headers and any supporting exhaust should not have a problem with either a stock or an SRT equiped engine.
Regarding underhood heat... I don't see a problem. If you have sensitive components that are close to the exhaust they generally have some kind of insulation from the factory, either a shield or wrap. Of course you can always use header wrap to spot insulate any actual components that worry you.
Instructor
Joined: Sep 2003
Posts: 1,237
Likes: 91
From: Canada
More info on coatings...
I have used ceramic coatings extensively in automotive and other powersports. On headers, a reduction in heat can exceed 200 degrees from using a ceramic coating. The coated headers also produced more power. Although I've never used Jet-Hot, I'm sure the results would be similar. Heat shields aren't usually required. The ceramic lowers the temp that dramatically. Forget about wraps too. They are fine and good for racing applications where the headers can be replaced often. The excess heat from wraps can cause the headers to degrade over time. Ceramic has no such issues. And it also aids in scavenging. Less heat, more flow, more HP and a nice chrome like finish. It's well worth the additional expense.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
RRocket, I agree.
The only ones that should order non-coated headers are those planning on modifying the headers during installation. This would only apply to 1990-1994 LS400s and 1992-1995 SC400s. There is still an unknown for 1995-1997 LS400s and 1996-1997 SC400s. ALL others should go coated.
That said, we may end up with an application specific header set for the earlier cars but for now the VAST majority of commited participants have 1998-2000 GS400s, 1998-2000 SC400s and of course 1998-2000 LS400s and these are bolt in applications.
The only ones that should order non-coated headers are those planning on modifying the headers during installation. This would only apply to 1990-1994 LS400s and 1992-1995 SC400s. There is still an unknown for 1995-1997 LS400s and 1996-1997 SC400s. ALL others should go coated.
That said, we may end up with an application specific header set for the earlier cars but for now the VAST majority of commited participants have 1998-2000 GS400s, 1998-2000 SC400s and of course 1998-2000 LS400s and these are bolt in applications.
Okay Jbrady, I am convinced. Change my order to coated headers. I will return your call this weekend when I'm not jam-packed with stuff to do, but when do you think I should be looking at paying for/receiving these headers?
And just to clarify, how much would I be looking at for the install. Am I going to have to take my entire engine out like rumor had it on my 91 I would?
Thanks,
-Jason Elcan
And just to clarify, how much would I be looking at for the install. Am I going to have to take my entire engine out like rumor had it on my 91 I would?
Thanks,
-Jason Elcan
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Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Originally Posted by Jasoneo5
Okay Jbrady, I am convinced. Change my order to coated headers. I will return your call this weekend when I'm not jam-packed with stuff to do, but when do you think I should be looking at paying for/receiving these headers?
And just to clarify, how much would I be looking at for the install. Am I going to have to take my entire engine out like rumor had it on my 91 I would?
Thanks,
-Jason Elcan
And just to clarify, how much would I be looking at for the install. Am I going to have to take my entire engine out like rumor had it on my 91 I would?
Thanks,
-Jason Elcan
My best guess on 1995-2000 year cars will be the engine will need to be supported and the engine mounts removed. I do not expect to remove the engine. The hardest part is removing the stock heat shields. That is why the trouble. On earlier and later cars this should not be problem. Install time I am GUESStimating at 6+ hours. Should be doable by a competent mechanic on jackstands. Obviously the better equiped the shop the easier the install.
I'm excited.
I want to make my installation an EVENT. Buddies, Video, Snapshots, the whole works!
Oh, and a Dragstrip test too! We'll have to see what they want to charge me for the dyno runs. They don't always tell the full story anyway.... MPH at the dragstrip does!
I look forward to finding out how to best get that header in there! From the top, from the bottem, what part may need unbolted to get it in there.......I don't care. I'll look for the options!
I kinda wanted my heat shields though......good weather protection. I may want to see how I might be able to keep some of that around....
I want to make my installation an EVENT. Buddies, Video, Snapshots, the whole works!
Oh, and a Dragstrip test too! We'll have to see what they want to charge me for the dyno runs. They don't always tell the full story anyway.... MPH at the dragstrip does!
I look forward to finding out how to best get that header in there! From the top, from the bottem, what part may need unbolted to get it in there.......I don't care. I'll look for the options!
I kinda wanted my heat shields though......good weather protection. I may want to see how I might be able to keep some of that around....
