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I wasn't looking for this however, once I read it, they look like a good option build quality wise. The one exception is the large ID primary pipes could hurt the bottom end.
Not a bad looking header for $600. The hand built part is my only concern. Hopefully their jig is spot on...
So what's the problem? Unless you are going to run no other restriction for back pressure? Like no Cats, no res, no mufflers, no pipe bends? With, or maybe even without a Tune.... those Headers are going to be a increase over stock in the entire RPM range.
RR Racing has sold some $1200 Headers that did not fit, and could not be installed. What's the worst that could happen for $600 for such a dollars spent vs results mod? I think you are overthinking this.
Three options on your topic question here:
1. Think about spending more than 2'xs the cost and hope they don't end up not fitting? (RR Racing - PPE Headers) Go through a hassle of your $1200 you are out of.
2. Buy the $600 Headers - PPE Clones. (ebay would refund if a problem right away). There are other ebay clones at -$600 on there also.
3. Just keep asking about Headers, and don't get any.
There at least is how I think,....... because you asked.
What all do you have done to your car? I was disappointed with the negligible gains after doing headers, and I wanted to blame oversized primaries. I have seen more significant gains switching over to 2.5" exhaust. If you want, I had a set of PPE headers custom with the smaller primaries made to mate up with a 2.5" midpipe. I've had them sitting around for years, just haven't made the time to swap them out.
What all do you have done to your car? I was disappointed with the negligible gains after doing headers, and I wanted to blame oversized primaries. I have seen more significant gains switching over to 2.5" exhaust. If you want, I had a set of PPE headers custom with the smaller primaries made to mate up with a 2.5" midpipe. I've had them sitting around for years, just haven't made the time to swap them out.
I know that you are a believer in the primary size effect. IMO to a point in a given range its negligible. There are also so many other factors. For example headers then the remaining exhaust system configuration back to the ending mufflers. ECU Tuning would also be a factor if looking at differences. Take two IS350 cars like for like. Do a 2.5 Exhaust change configured matched w/ No headers on one car. The 2nd car the same with Headers, and the samee 2.5 exhaust system. Dyno and track time time. My money goes the the car with the headers, slightly larger primaries and all.
Your above post experience has me wanting to understand a few things like? Define "negligible gains after doing headers"? Why would you blame the headers size only? Was there any ECU tuning done? What measure do you have to share that the 2.5 exhaust only showed more "more significant gains"?
Just a FYI: There have been 2 instances in the past here on CL a few years back when headers were produced and sold/purchased on the theory of using the smaller primaries would be better. After numbers of members installed them, there was little to no difference vs the stock header configuration. With those that installed a number of different exhaust changes were made to try and help produce better gains. None of those exhaust changes along with the smaller primary headers really made to much of a difference vs stock.
On paper like the Century performance link sounds good. Paper vs actual test and results are a different story. I would love to see a actual of the 3.5 V6 2GR with the larger primaries, and exhaust change that lost hp? In the CP link am I seeing info on:
"a 433 cubic inch big block Chevy engine and data? I also see data referring to: different camshaft with a wider lobe centerline, or in the very least, high ratio rocker arms on both intake and exhaust valves. This change would flatten out the torque curves on either header length."
"However, I'd like more information on what intake manifold was used on this engine."
"step-header technology"?
"This data uses a 500" engine with an optimum RPM (where the engine will spend the majority of time) of 9,000 RPM. It shows the best single stage, two step, and three step header dimensions."
Let's get some 2GR actuals data to these post? I'm just asking based on the statement made for the measures one came to the conclusions on?
Last edited by jgscott; 02-18-22 at 06:30 AM.
Reason: Spelling & Grammar
Sir, did you actually analyzed the info in the link above, and see what type of motor that was based on?
Don't get me wrong, there is a calculation relation to starting with that, the primary tube should contain the same volume as the cylinder and goes on and on from there, but that link is just useless in this case for you statement of some do and don't for a answer on our 3.5 V6. lol!
For the most part here maybe the one most thing in relation they talked about that is not mention here: C "This is due to the fact that most full length header designs are for max power, and upper RPM use. Additionally, in racing applications we often use the collector length to slightly tune the torque output of the engine."
But....... Collector length is Not just a effect for a Racing engine only.
The main object is to get the burned exhaust gases out of the engine, so the intake charge can enter. All other is just pages of variables and wasted theory Many have a hook on the best theories of how to do this best. It then leads to the same thing of flow, and a system that helps to syphon the exhaust out of the head a Venturi of sort with scavenging is best. I'm not even going to go down the rest of this road. I don't need to know what I already understand.
The rest is just way too much overthinking. Are the header choices for the Lexus 2GR V6 better for your objective that the Stock manifold? Is what you have to compare if that's you objective is all? No more, no less? That's what the original op is only asking about the Ebay headers he posted.
My "gains" are judged by logged maf values. I didn't observe any increase in peak values doing headers and it felt like I had a weaker mid range. They are definitely not worth doing with a mostly stock IS350. I don't have logs of 2.5" exhaust without headers, but the logs of going from a custom dual 2.25" exhaust to a very similarly setup 2.5" showed measurable results and was cheaper to do than headers. Perhaps by now I make enough power to notice gains from 1 3/4 headers over 1 1/2. The main reason I lost interest in installing my custom headers is that I have traction issues as is and it would be pointless to do something in an attempt to make more midrange power.
Sir, did you actually analyzed the info in the link above, and see what type of motor that was based on?
Don't get me wrong, there is a calculation relation to starting with that, the primary tube should contain the same volume as the cylinder and goes on and on from there, but that link is just useless in this case for you statement of some do and don't for a answer on our 3.5 V6. lol!
For the most part here maybe the one most thing in relation they talked about that is not mention here: C "This is due to the fact that most full length header designs are for max power, and upper RPM use. Additionally, in racing applications we often use the collector length to slightly tune the torque output of the engine."
But....... Collector length is Not just a effect for a Racing engine only.
The main object is to get the burned exhaust gases out of the engine, so the intake charge can enter. All other is just pages of variables and wasted theory Many have a hook on the best theories of how to do this best. It then leads to the same thing of flow, and a system that helps to syphon the exhaust out of the head a Venturi of sort with scavenging is best. I'm not even going to go down the rest of this road. I don't need to know what I already understand.
The rest is just way too much overthinking. Are the header choices for the Lexus 2GR V6 better for your objective that the Stock manifold? Is what you have to compare if that's you objective is all? No more, no less? That's what the original op is only asking about the Ebay headers he posted.
Yes I understand. The whole point was to use as an example. If you look at our performance section here. It's the the same handful of people commenting over and over. Not many new members engaging. I'm sure there are a few members out there that read this suff, and be like all this is foreign language to me.
So what's the problem? Unless you are going to run no other restriction for back pressure? Like no Cats, no res, no mufflers, no pipe bends? With, or maybe even without a Tune.... those Headers are going to be a increase over stock in the entire RPM range.
RR Racing has sold some $1200 Headers that did not fit, and could not be installed. What's the worst that could happen for $600 for such a dollars spent vs results mod? I think you are overthinking this.
Three options on your topic question here:
1. Think about spending more than 2'xs the cost and hope they don't end up not fitting? (RR Racing - PPE Headers) Go through a hassle of your $1200 you are out of.
2. Buy the $600 Headers - PPE Clones. (ebay would refund if a problem right away). There are other ebay clones at -$600 on there also.
3. Just keep asking about Headers, and don't get any.
There at least is how I think,....... because you asked.
It could be that our needs are different? Peak horsepower isn't everything if you loose the holeshot due to lost midrange torque.
A header that scavenges well through the midrange has its benefits.
IMO, equal length headers do little to nothing for our cause as there is no adjacent cylinder firing directly afterwards. That said, simply keeping the primary tubes as smooth as possible and dumping them into a longer collector would likely be the most beneficial but I have no desire to build 5 sets of headers to find out.
Will V8 sized primaries and shorty collectors help the 3.5 breath compared to stock? Most likely. And hopefully it doesn't hurt the midrange too bad, but there is little data to compare too as no one has data from small tube runs that I can find.
It could be that our needs are different? Peak horsepower isn't everything if you loose the holeshot due to lost midrange torque.
A header that scavenges well through the midrange has its benefits.
IMO, equal length headers do little to nothing for our cause as there is no adjacent cylinder firing directly afterwards. That said, simply keeping the primary tubes as smooth as possible and dumping them into a longer collector would likely be the most beneficial but I have no desire to build 5 sets of headers to find out.
Will V8 sized primaries and shorty collectors help the 3.5 breath compared to stock? Most likely. And hopefully it doesn't hurt the midrange too bad, but there is little data to compare too as no one has data from small tube runs that I can find.
I respect your Opinion but I need some backup with it of data and actual. Please provide? Everything I see says much different than what you are thinking and saying.
Take a good look at some 2GR Dynos with Headers. There are many out there. You will notice that just about every dyno with headers vs no headers, the header ones picked up 12 - 20+ hp in the midrange. With a Tune was even better. Here is a good example. Yes one is a Camry with a D3 Tune like I have on my car now, with the Same newest 2GR motor, with Headers and Tune. Reason I linked it is because it consistent, same car, same dyno, same mods, and a Tune. Even... w/o the Tune I see 10 - 15 hp gain from 3000 up everytime. In fact most dyno's showed more hp gain in Mid that at peak.
Look at the graph from 1000rpm on up.
* Edit look at vid starting at 11:55. Look at the Stock Redline indicated Stock Dyno. Look at the Gains from 1000rpm on up. The Headers gained from 1000rmp on up over Stock. Larger Primary's and all.
So here is a look at the smaller tube headers vs larger. Go to 13:25 in the Vid. Look at the Midrange. Yes they are different but the Tube size? You be the Judge?
02-15-22, 10:47 AM
Header options at a reasonable price
Yes I understand. The whole point was to use as an example. If you look at our performance section here. It's the the same handful of people commenting over and over. Not many new members engaging. I'm sure there are a few members out there that read this suff, and be like all this is foreign language to me. 
