Linked or non linked decats, whats your experience?

[assynt road]

As above really, what's best in your opinion? Have got both types and are wondering which to use on my 4.2 with my new ACT big bore system.
Cheers, Steve.

[PaulK]

Linked is the way to go had both and linked is a bit quieter than independents but supposed to give a bit more power.

Paul

[scotty_d]

I had been told that unless the car makes 400+ bhp, no point in a linked system.

[Byker28i]

I've got unlinked - dead easy to put in and out at mot time

[assynt road]

Thanks guys, no real consensus then, a case of either or?

[Supateg]

Act quite system is linked in the back box therefore I didn't require a linked decat according jools

[spitfire4v8]

Linking upstream is good if you have a restrictive system further downstream .. sharing the exhaust across two pipes means more total flow. The better the exhaust flow downstream the less you need to link them upstream. In the case of the act new system the pipes are very nicely shaped, and as it's linked into a central chamber in the silencer there's no point in linking at the decats, the flow will already be very good (big pipes, gentle bends).
The best results from linking upstream come when you have high hp into a small system, so higher hp 4.2 cerbs respond very well to linked decats, so much so I had to do a special chip for them even when fitted to otherwise std cars to prevent flat spots.

[pjac67]

Hi Steve.

My experience (not conclusive so may be a complete red herring).

http://www.pistonheads.com/gassing/topic.asp?h=28&...

Coincidentally I think my Griff engine went pop this morning :-(

[assynt road]

pjac67 said:

Coincidentally I think my Griff engine went pop this morning :-(

Nooooooooooooo!

I hope not Paul, that really would be bad luck, such a monster too.....

Thanks for the link to your cerb troubles, food for thought I think. Lots of troubles about today, I managed to break a bone in my hand before 0630 this morning, no TVR driving for either of us for a while........

[Cyclone1]

pjac67 said:

Hi Steve.

My experience (not conclusive so may be a complete red herring).

http://www.pistonheads.com/gassing/topic.asp?h=28&...

Coincidentally I think my Griff engine went pop this morning :-(

pjac67 said:

Hi Steve.

My experience (not conclusive so may be a complete red herring).

http://www.pistonheads.com/gassing/topic.asp?h=28&...

Coincidentally I think my Griff engine went pop this morning :-(

Sorry to hear about your Griff.

First time I've read your post on linked decats and find it strange that these could be quoted as being the potential cause of piston failure. The link occurs as the gases are being exhausted away from the engine, balancing occurs post the the link so the only variables that change are back pressure and fuelling but these are negligible.

I would be very disappointed if a reputable engine builder quoted this as the root cause or a potential cause,good engine Builder should be able to identify the cause based on the condition of the components once stripped.

Not sure this helps this thread as I think the OP's question has been answered.

I had linked decats on my 4.5 for many miles with no issues.
Jules

[ridds]

Have linked on mine, MUCH quieter than with the separate de-cats. Mine makes 400bhp with short induction, Joos generic chip and Blueflame rear silencers.

Not done any sort of back to back with them but I prefer the exhaust note with the linked pipe for general road use.

[assynt road]

Right thanks guy's, I'll go with the linked variety I think. Just got to wait for the new pipes to arrive now.
Steve.