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Assuming a person chose to go with 2" exhaust primaries on their LT headers, the circumference of each 2 inch diameter cross section is 6.28 inches. This multiplied by 4 on each side, brings it to 25.12 inches of total circumference.
Meanwhile, norcall and AFE downpipes, are 3 inches in diameter. This equates to 9.42 inches of total circumference.
Assuming both LT and norcal are the same distance traveled through the engine bay, the LT headers have over 2 and a half times more surface area, which means they will radiate much more heat.
While there are coatings and wraps that prohibit heat transfer, these coatings and wraps also prohibit heat transfer if applied to the norcal or AFE downpipes, thus, this constant can be removed from the discussion.
In any given amount of time, the LT headers will emit more heat than the catless downpipes.
The CAT on the stock downpipe that is located next to the oil cooler under the engine, raises vehicle engine oil temps.
Long Tube headers, and their 4 tubes being merged into 1, near the oil cooler, also raises oil temps.
The cat having a larger circumference emits more heat.
The Norcal SS or AFE emit the least amount of heat of the 3 options, and also emit the least amount of heat relative to the stock oil cooler, and are also the furthest distance away from the engine oil cooler. This trifecta is why the catless downpipes are the "coolest" option for an LT1, LT4 or LT5.
Not only do they emit less heat, the emitted heat has a further gap of air to travel across to get to the oil cooler, and the engine block down the entire length of the downpipe or LT header.
Keep in mind also, as mentioned above by members who understand the full picture to addressing this problem... the ZR1 can't be tuned, and the LT headers may require tuning.
While some shops have added LT headers to their vehicles, those shops have also expressed to members of our team, over the phone, that their upgraded zr1's "become a potato" at times, as the car is very intelligent and great at detecting aftermarket parts, as GM has programed it to resist tampering, and punish customers who attempt to do so.
Those shops then go through a procedure to get the car to run again. Such a situation is not ideal if a person is trying to "win a race" or set a good lap time, such as Poorsha. Nor does one want these lockup/shutdown events being logged in their car's black box, as it MAY eventually be used against the owner to void warranty.
Also keep in mind, the car data logs this and transmits it via OnStar. It is believed that GM may void warranties if they detect tampering. LT headers may or may not be considered tampering.
LT headers cause engine lights to throw more often than not on the z06, so it is likely they may do the same thing on the ZR1. Since the ZR1 cant be tuned, this presents a problem.
And to say LT headers produce less heat, than the catless downpipes, is a statement that contradicts most observations by forum members who log oil temps as they road course their z06, which have been upgraded to the catless downpipes, and wrapped them or used coatings.
It also contradicts simple physics of surface area and heat transfer, as described at the top of this post.
Our team will have these Norcal or AFE catless downpipes and catless X pipe on a 2019 zr1, very soon. We will let you know how it goes. Going through the 500 mile break in period as we speak.
a norcal cat delete kit or equivalent with your x pipe will stop your burning up cats situation. also if same as zo6s it wont throw codes or need a tune. plus side it will lower under hood temps. its a fairly easy to reverse if there are any war issues. side note,,, tube headers on our cars will raise under hood temps compared to stock manifolds that retain the heat better and they are not far behind in the power dept from good headers!
Charlie,,,
all 100% accurate information.
Be careful listening to certain other members in this thread, the only way their advice is accurate is if it was a known fact that it was "opposite day" when they wrote what they wrote.
Be careful listening to certain other members in this thread, the only way their advice is accurate is if it was a known fact that it was "opposite day" when they wrote what they wrote.
Be even more careful of other members touting Cat delete pipes as good as headers. When anyone who has added and run headers many times knows. Then it makes no sense that headers with cats only do a few hp less than catless headers. So how could a cat delete pipe add much? Then no dyno results?
Where headers have 1000's of proven gains on multiple runs. Tons of dyno results! I have bought 6 sets of headers in my life and all made a nice gain.
Many guys here know the truth about headers and coated headers as well. But some have never bought them installed them or owned them.
Talking completely through their own hat! DEAD wrong!
For cars with bigger power they are a must.
Many know like me who have bought many sets and dynod them over the years and it is the best basic mod you can add. Along with an aftermarket intake and tune. the
The best info would be from many FORUM VENDORS who sponsor the forum. I would call Nick at American racing headers.
Vendor RDP sees about 40-45 rwhp on the 2 inch ARH installs. Call them and see don't just believe otherwise. No proof for one reason.
Find out the reasons why long tubes are and away better. Proof beats BS everytime!
Just look at Ben at Weapon X. He did not even consider a cat delete over Custom long tube headers. On his ZR1
My car picked up a solid 40 rwhp. From my ARH install!
Then the 35 pound weight cut is very sweet as well!
The gauge of the stainless on header primary vs the heavy cast is a lot. 1 Cast iron manifold weights more than both primary headers
Put together I weighed each piece and added the weights full 35 pounds lighter plus even more weight saving on headers with no cats!
My car picked up a solid 40 rwhp. From my ARH install!
I am curious, did you do a baseline dyno on your stock zo6, then install headers and re dyno car {same shop, similar conditions} without tuning and picked up 40 rwhp? or was the gain 40 rwhp with headers and tuning?? I would think a good tuner would definitely want to tune car to get the most out of a header+full exhaust install. if its the second scenario we then have to decide how much gains were from the tune and how much was from header??? only real test would be back to back testing header vs cat delete x pipe on same car and same dyno.
Charlie,,,
Looking to do some upgrades soon. Currently I have an x pipe and axle back, but now I want to start modding for more power. I'm leaning towards the Magnuson 2300, but I don't want to get too deep into it like doing headers, meth, and what not. Ideally I would like to strap the 2300 on, get it tuned, and make a solid 650-700 whp and call it a day. I have also been thinking about doing a lower pulley and intake, as I think that would get me around the 650 mark. I have spoke to a few shops and some say you have to upgrade the headers because there is a high risk of melting the cats when you increase boost. I don't buy that. I know there are tons of people on here making more power with more boost and haven't touched the manifolds/cats. So what is the general consensus? Can you raise boost and make good power without doing headers as well?
Do my cat delete kit one guy just made 30 more at wheels nothing touched
Looking to do some upgrades soon. Currently I have an x pipe and axle back, but now I want to start modding for more power. I'm leaning towards the Magnuson 2300, but I don't want to get too deep into it like doing headers, meth, and what not. Ideally I would like to strap the 2300 on, get it tuned, and make a solid 650-700 whp and call it a day. I have also been thinking about doing a lower pulley and intake, as I think that would get me around the 650 mark. I have spoke to a few shops and some say you have to upgrade the headers because there is a high risk of melting the cats when you increase boost. I don't buy that. I know there are tons of people on here making more power with more boost and haven't touched the manifolds/cats. So what is the general consensus? Can you raise boost and make good power without doing headers as well?
i melted my cats with my first set of mods. AFE 15% pulley ex tank and tuned. You’re dreaming if you think a pulley and intake will get you 650 rwhp. I now have kook LT and a a 2300 Magnuson added to the above mods a am making 661on 91 octane. Need to upgrade fuel to move farther up the hp scale. Be realistic about your goals. Don’t believe everything you see on this forum. My 02 cents.
Here is what the cat looks like that just came off my stock ZR1 with just over 4000 miles on it (1500 of which were break-in).
Wow the actual cat is in the round larger part. The pipe failed. The cat is probably toast too since it is right there. You should test for GM they must not run them as hard as you do to make the pipe burn through.
Design flaw. The cat restricts the flow and the heat burnt through.
Getting hot is an understatement. It cannot handle the heat from the manifold outlet right above it at the bend it is right at the transition
One of the things Tadge said about the zr1, was that it expanded the exhaust side piping like water balloons from heat, and that they had to go with thicker metal vs the z06.
Apparently, they need to bite the bullet and use titanium. Good thing you have a warranty. It will be interesting to see if you are able to do the same thing to catless downpipes or headers. My gut is that you will balloon them all out poorsha.
hopefully the lack of Cat restriction benefits you instead. The catted GM test car spit fire, a zr1 without cats... is going to look like an f16 out the back
Last edited by RoxyCarter; 11-10-2018 at 07:46 AM.
I have seen this on z06s also. Like I've been saying the cats restrict the flow to much. I posted pics of the cells from z06s and was a main reason I ca mn e out with my cat delete kit
out of curiosity, if something happens like with Poorsha's pipe, to one of your pipes, if put on a zr1, would a person have to buy a new set, or do you have any kind of guarantee where you would exchange it?
Well Poorsha, there is your green light. I think that seals the deal for Roxy's zr1, which pipe we plan to put on the car. No sense in begging AFE to do the same thing, if norcal agrees to warranty it, then we will support local forum vendors, and buy from them for our test car.
Well Poorsha, there is your green light. I think that seals the deal for our zr1, which we plan to put on the car. No sense in begging AFE to do the same thing, if norcal agrees to warranty it, then we will support local forum vendors, and buy from them for our test car.
Thanks. I'm actually not worried about Norcal-SS standing behind his product as much as I'm worried about GM if something else goes wrong with the car. I have a Borla catless x-pipe at home that I bought just to try and get some heat out from under the car but never put on. That said, I am seriously considering getting a set of the Norcal-SS pipes and running that and the x-pipe for track days.
On a related notes, has anyone tried swapping the x-pipe and downpipe without separating them? I'm just wondering if that's any easier if I plan to make the swap on a regular basis. Also, are the cat to manifold gaskets really single use or are folks reusing them? Thanks.
11-09-2018, 10:51 AM
