3rd Cat Delete Fitment

[Bimmernate]

Unfortunately that hasn’t worked for me. The pipe only reaches here which is about an inch too short. I’m this close to going to have someone cut it.

Can you line up the flanges by having a hand on each one and pushing them together? Or they just aren’t passively lining up?

 

[NCThirteen]

I love how people think that they need a TI exhaust system. While it is lighter than other materials, it is not the best thing to use for an exhaust system unless you plan on shaving every ounce of weight. For longevity there is nothing better than good stainless steel.

 

[Bimmernate]

Unfortunately that hasn’t worked for me. The pipe only reaches here which is about an inch too short. I’m this close to going to have someone cut it.

What I also find interesting, is my miltek pipe has the “not for road use” engraving on the other side of the pipe (faced up) so you cannot see that once installed.

 

[scf100]

Everyone should post what year car you have....that may make a difference........my install was on a 2025 with Miltek....perfect fit

 

[GRP]

The problem is that we're trying to mate a part made by Lotus to an aftermarket part made by another company with a different jig (i.e. Milltek and GRP). I'm sure the Milltek delete pipe mates perfectly with their OWN exhaust, and similar with GRPs.

The small variances in manufacturing will have an affect, so personally, I would opt for the smaller opening and use shims if needed, vs risking the cat delete pipe being too large and then having to mess with expanding the stock exhaust.

Both pipes work...but both may have issues mating while other's may not experience any issues. The GRP is almost $100 cheaper for the EXACT same pipe. It's just a hollow bent pipe. That's why I went with the GRP version and just used two shims which cost me another $4 from Amazon. I didn't even bother with a pipe expander...

This^
How many here have installed multiple decat pipes on multiple cars?
I can tell you that while our decat pipes outlet OD remained nearly identical (+/- .05") between the 5 that i have personally installed the inlet diameter of the oem mufflers did not remain identical. A couple fit nice and snug while a couple needed the shim trick.
There is always going to be variation from manufacturer to manufacturer, part to part etc We have had a few people report the milltek pipe being too large as someone else in this thread has posted as well.
At the end of the day we do our best to keep things as consistent as possible but again there is always some manufacturing variation on our parts end of things and the Lotus end of things to deal with.

 

[Nelumbo]

This^
How many here have installed multiple decat pipes on multiple cars?
I can tell you that while our decat pipes outlet OD remained nearly identical (+/- .05") between the 5 that i have personally installed the inlet diameter of the oem mufflers did not remain identical. A couple fit nice and snug while a couple needed the shim trick.
There is always going to be variation from manufacturer to manufacturer, part to part etc We have had a few people report the milltek pipe being too large as someone else in this thread has posted as well.
At the end of the day we do our best to keep things as consistent as possible but again there is always some manufacturing variation on our parts end of things and the Lotus end of things to deal with.

My Milltek (thanks, Greg) fit tight in the muffler and I ended up slightly less than a centimeter away from seating it all the way to the "fat" part. This positioned the muffler back a similar amount such that I had to gently push the muffler close enough to engage the mount/bushing threads. There's some built-in flex in the headers that allowed for this but I still don't feel comfortable putting that slight stress on it. I hadn't thought of a better way to expand the muffler to get the Milltek fully seated until after putting it all back together again. The other end with the exhaust gasket lined up quite well, though. For some reason, however, the entire muffler ended up shifted very slightly to one side. I will note that one of the nuts of the three supplied did not fit, likely the wrong thread. Luckily I had one laying around that did fit but it's negligibly smaller in outside diameter.

 

[GetawayDriving]

Update on mine, I eventually got my Milltek to fit after expanding the factory exhaust several times. Even with that expansion, it was TIGHT. Needed the lubricant and a lot of muscle to get it to work. Also needed to loosen one side of the exhaust hangers, then fit the pipe, then re-tighten exhaust with the new fitment.

 

[Arafaat]

Just got the @GRP pipe and it is too loose They will try to expand later in the week and said they’d never had an issue with Militek pipes. This the official service center who have installed plenty. Hope it works because I won’t be able to send it back to the US to be replaced.

 

[scv]

Using a couple of shims easy and allows tight fit…...

 

[scf100]

Second 3rd cat delete done…….first on a 2025 v-6 then recently a 2026 V-6……both with the Miltek pipe and Miltek 2 controller

Everything fit as should on the 2025.

On the 2026 had to buy a pipe expander from Harbor Freight and expand the factory exhaust beyond the indentation on pipe ( see circled area). Once that was done and sprayed with WD-40 got the Miltek pipe in after twisting a lot.

Also a block of wood comes in handy along with a hammer to knock the 3rd Cat out…….also an crowbar is needed to separate pipes……otherwise the video on how to do the delete on this site and YOUTUBE is spot on.

 

[Glowtus]

I performed the Millitek install today. The fit was VERY tight. I ultimately had to put the pipe in the freezer for 20 mins, and put some Permatex Anti-seize on it, and then it went on much easier.