Fitment issues with Top Gear catted 200 cell x-pipe.

[Marky911]

Are you not concerned about stress on the headers? I feel like that's just asking for them to crack, being under constant load like that.

which at the time were genuine manifolds.

The whole system on Craigs (cobra) car has since been renewed including stainless manifolds. :thumb:

But yes the fitment of the TG stuff onto std manifolds was far from ideal. Yet this is what TG would rather see you do than them have to accept it back again and come up with a proper solution.

As said, for most people they're fine but there are enough folk having issues to make me think that it isn't a fault with the OEM gear.
The TG stuff is ok, budget gear. Nothing more. It's nice that you can switch it etc but as far as quality goes it's pretty average and their aftersales support doesn't extend very far, as the OP is finding out. :nooo:

 

[cobrars]

Are you not concerned about stress on the headers? I feel like that's just asking for them to crack, being under constant load like that.

I was at the time, but with TG saying their "JIG" was set up correctly and the cats are exactly as they should be, I thought maybe my manifolds had slightly warped with heat or something, so just done what they suggested.

I very shortly after fitted stainless manifolds too and everything seemed to fit ok at that point, so I can only guess the cats expanded to the correct size.


Craig

 

[thefleshrocket]

I ordered the 63mm pipe. It arrived and its dimensions were noticeably different from the 54mm pipe--the cats are much closer to the exit pipes on the 63mm version.

 

[thefleshrocket]

Hopeful, I test-mounted the x-pipe. I discovered that if I bolted one side to a manifold, the other side would be at least 1/4 inch misaligned with the bolt holes on the other manifold. I reached out to Top Gear, and their tech told me to slide the bolts through both sides at the same time, and then slowly tighten the nuts, as this would cause the two surfaces to line up. I told him that I didn't like that idea, because I felt like it would put stress on the manifold and potentially crack it.

 

[thefleshrocket]

Then I had a bright idea--what I used a spacer to move the x-pipe slightly away from the manifolds. Since the manifolds are angled in and the x-pipe tips are angled out, a spacer might be enough to get things to line up. To simulate a spacer, I put nuts on the bolts on the x-pipe and then pushed the exposed threaded area of the bolts through the holes on the manifolds. It worked! I then loosely test-fit the mufflers, and they seemed to fit too!

 

[thefleshrocket]

I reached out to Top Gear, and their tech agreed to send me some spacers, gaskets, and longer bolts. They showed up yesterday, and I went to work getting it all together. It was a pain to get a spacer and two gaskets on each side of the x-pipe to line up with the manifold without me dropping something, but I eventually got it bolted up. Everything fit properly, though it did take some "leverage" to get the muffler inlets to line up with the x-pipe outlets since the x-pipe's slightly-rearward location made those two pipes slightly offset. (Basically, instead of putting stress in the exhaust manifolds, it's now been transferred to the mufflers, which are on mounts that are a lot more flexible.) I went for a test drive, and there are no leaks, and it sounds BETTER! Not really any louder (yet) but more of a thrummy exotic note in the upper RPM range. Of course I forgot to take pictures of the completed setup as I was excited to get the car off the lift and tested. I'll take some pics next time I'm under it.

I've contacted the Top Gear tech to let him know that the issue is resolved, and to request that he send me a DHL shipping label to send back the originally-ordered 54mm exhaust.

 

[Marky911]

Glad it's sorted! What a chew on.

Got there in the end though. That's the main thing.

 

[Griffter]

Good work, well done. I wonder what the root cause was though and whether only some fitments will be affected.

 

[thefleshrocket]

Follow-up. Top Gear sent me a shipping label to send back the 54mm exhaust, and gave me a credit for the full purchase price, so I am happy with how those guys made good on the whole deal.

The 63mm 200-cell x-pipe is still installed. It sounds much better than the factory pair-of-triples non-crossing exhausts. On top of that, there seems to be a healthy bump in power. I'm not one whose SOTP dyno goes gaga over small upgrades, but in this case, I think the change is noticeable. Below 3000rpm, there might be a small loss on power. Small. As in, the car gets past this RPM quickly enough that it's a non-issue in daily driving. 3-4K feels a little stronger than normal, but from 4K on up to 7K, there seems to be a noticeable bump in power. Like, it's extra rewarding to run the motor out past that. I wouldn't be surprised if the dyno said there were 20 extra ponies in the stable.

Given that literally every other x-pipe manufacturer wants double the money of Top Gear's systems, and given that it seems to be made of quality materials and craftsmanship, and given that your 911 will sound extra beautiful after install, I recommend the Top Gear 63mm x-pipe. Just be sure to ask for the spacers and extended bolts that I got, in case yours doesn't line up out of the box. Oh, I also bought a pair of spacers for the rear O2s, just to be sure that they don't throw any codes.

 

[Jamesx19]

Good work, well done. I wonder what the root cause was though and whether only some fitments will be affected.

Just fitted the 54mm standard pipework version to my 996.1 with the cheap eBay stainless manifolds and Cargraphic boxes. No issues at all and all lined up better than the crossover pipes that were on previously.

Remarkable considering having to join four pipes onto one piece of metal fabricated hundreds of miles away from the car.....

Also liked the fact that the standard pipe diameter had been expanded slightly to take account of the larger diameter exit from aftermarket headers or manifolds and avoid a downstream mismatch of the pipes. Nice attention to detail.