Disclaimer: This applies to DNA Motoring/KOSpeed. I would like to verify other sellers if purchasers wouldn’t mind measuring and posting pics to this thread. I will also update this thread with sellers with true 1-3/4” primaries from eBay once getting confirmation from anyone who shares the info.

11/26/13: Speed Engineering are now 1-3/4" primaries: https://ls1tech.com/forums/generatio...available.html

6/7/13: Speed Engineering are currently 1-5/8" primaries: 6/21/13: Speed Daddy are 1-5/8" -- see post #89

7/1/13: PaceSetter are indeed 1-3/4" see post 91

I purchased a set of eBay stainless long tubes from seller KOSpeed (kospeed2008; part number HDS-CC98LS1). KOSpeed is DNA Motoring. The shipping label, email, paypal, etc. all said DNA Motoring. I’m guessing KOSpeed is simply another account they use to sell even cheaper (I paid $182). Based on the information someone had mentioned in another thread (https://ls1tech.com/forums/17447366-post39.html), I decided to measure to ensure these really were a 1-3/4” primary. Unfortunately, I determined they are actually 1-5/8” primaries. They are also 15g steel (at 3.002 OD and 2.862 ID, that leaves us at 0.14/2= 0.07" or 14g; info from http://www.engineersedge.com/gauge.htm)

These are advertised as “1.75-inch inlet” – which is true. Unfortunately, that doesn’t mean that is the primary size. What it appears is happening is they are taking the 1-5/8” primaries and expanding them to 1-3/4” “inlet” at the weld to the header flange.

Below are pictures of all of the findings. I hope this might help people to determine if they really want to save the money going with the eBay longtubes. I’d implore anyone who has purchased a set to measure your primary tubes rather than the inlet to verify diameter. I’m interested to know how many have put these 1-5/8” headers on and the gains they noticed.

KOS/DNA has been prompt in sending a RMA so these can go back. Unfortunately, I'm out $60 for the return shipping. I would try and fight it, but nowhere does it mention these are 1.75” primaries – only 1.75” inlet. At the very least, I'm hoping this is my financial contribution to save someone else some money!

OD of primary (random spot) appx. 1-5/8”:



OD of primary near collector appx. 1-5/8”:



Gaskets and studs:



Bungs on outside of collector:



Inside of collector:



OD of collector is 3”:



ID of collector is appx. 2-7/8”:



Now the primaries…

Inside at flange (notice the flare):



Outside at flange (notice the flare):



ID of flange at the flare appx. 1-13/16”:



OD of flange at the flare appx. 1-3/4”:

 

Thanks for posting this. For anyone that wants to know this stems from a thread about ebay headers located here....

https://ls1tech.com/forums/generatio...-new-post.html

Some poeple say all ebay headers are the same, though I tend to doubt that. I do not believe there are tons of people manufacturing them, but two or three seems realistic at this point. Pictures speak VOLUMES so as speed demon said, if anyone else has a set that seems more legit please post pics and let us know. Thanks!

 

Are those the headers that are like $190?

 

Yes. Most all of the headers on eBay are in that price range. They can fluctuate occasionally because they go "on sale" for like 5% off at times.

 

Don't have any pic but when I got mine they measured fine I will see if I can find out who I got mine from as it was a few years back

 

I've got a few year old set on my car - and it's been 123mph on the motor and 131mph on the gas.

They work good for the price

 

Mine were the 1 5/8 and my 2000 ws6 a4 with factory stall and gears with only bolt on's made 345rwhp and 353rwtq on two different dyno's, so they worked for me, they're probably nothing I'd put on a bigger build, but for a budget and small build they worked perfect for me! When I sold the car they still looked shiny and nice

 

That would be great! A pic verifying their outside diameter and the seller/brand will help us add to our 1-3/4" listing.

Happen to have the brand/seller and pic of the OD primary?

Forgive me if I'm wrong, but I read through your thread several times before rolling the dice ordering these longtubes and I did not see you mention that you measured. I also don't remember which brand/seller you had.

 

Opinion Racing was the brand had to do some digging lol. I do not have any pictures but I did measure them when they went on. I can measure them on the car if you like for outer diameter

 

Does this apply to the speed engineering headers?

Also obviously on a bigger build this will have an impact but on a car that is ptp tb, ls6 intake, lid, catback and ory would it have a big impact or one at all?

 

^^^you should be fine I am using them on a cam set up not speed daddy but eBay headers. I put down some pretty good numbers. 373/371 that's with out ported tb, pulley, and with a very poor homemade y pipe.

 

You guys keep taking about the times you ran with them, and the numbers you put down. That's fine and dandy if you're content.

The point is though there's more power to be had with a larger primary.

OP, nice to see someone take the time to CALIPER the headers and post good pics.

 

Wile this is true for under 200$ shipped its a great budget. You can take the money saved and put it somewhere for bigger gains. I will change mine out eventually to bigger ones but that will be after heads and everything else is done. Also for people with a budget they can not be beat

 

Very true statement

 

Yeah, I would expect this out of a $200 header. I mean hell, it's $200! LOL

 

That would be great

I posted in their thread with a link to this thread as I'd like to know as well. I've not seen a response, but I'm hoping that their price difference means they use the larger 1-3/4" primaries. Until they confirm, I am going to assume they are identical to the other eBay options (ie: it would be in their best interest to confirm for everyone).

My pleasure... just wish it didn't cost me $60! Perhaps Speed Engineering would like to waive shipping on a set for me since if they're indeed 1-3/4" then I'd like to think I've just sent them a bunch more business.

The issue that I have is that everyone has assumed this entire time that they're getting 1-3/4" long tubes from eBay. I personally can't justify spending $500 more for TSP 1-7/8" to jump from $200 1-3/4" -- if they were actually 1-3/4" primaries! Now that we may be finding all the eBay headers are 1-5/8"... well, that paints a completely different picture, IMO.

 

Just found out Speed Engineering are also 1-5/8" primaries: https://ls1tech.com/forums/17458386-post76.html

 

What is the gauge of the tube wall. Have you measured it? If its presently 16, and they go to thin wall 18ga on there new race version then they will flow very close to 1 3/4 . They can keep the the same OD , but by going to a higher gauge they will be increasing the ID and they will flow close to 1 3/4 But the end result is a cheaper product .

 

Will this really make a difference? I was gonna do speed's headers but am alittle worried not. I'm not really in the position to buy TSP's right now.

 

This makes a difference when you currently have a 1 3/4" header and want to upgrade to a larger primary like a 1 7/8" header. Too many people post that they are selling a 1 7/8" header because they measure the header flange opening, which is a universal piece that everyone uses to build their headers, but it's the actual primaries that make the difference.

Sure, for a stock bolt on, even a head cam car, the differences are probably minimal, but for me, I've got a set of killer heads, decent cam, and a procharger pushing 15psi of boost so I need the larger primaries for my application.