People seem to be happy with the results from adding extractors on their 3.5L.

Would there be any benefit of adding a set of extractors but not upgrading the rest of the exhaust on a KJ2?

Thanks

The biggest restriction is the rear muffler. I think you would be wasting your money if you did any exhaust modifications and left the standard KJ2 muffler in place.

If youre worried about a loud droney exhaust..

A simple Lukey muffler would the best bet with regards to removing restrictions or a 2nd hand Sports/GTV exhaust.

Add to that, your extractors and you're doing well.

But to answer your question.. Not recommended due to the restriction of your rear muffler.

SuFz

What sort of gains (both dyno and how it feels) are to be had from doing both? I was considering doing the same as the OP, extractors and stock muffler

I really like the stock muffler, it's whisper quiet when cruising, has a gentle but audible growl letting you know its a big 3.5 in the 2500-3500rpm range. And above that its loud enough to feel grunty but doesn't stick a big "I'm a dickhead" banner across your windscreen every time you stab the throttle like so many Hold'on Flogadore and Fooaaaard Failcon's floating around with straight thru's bru! :facepalm

If I was ever going to swap the muffler, it would have to be similiar in noise levels to the stock one. I.e. not noisey at all

Agree with Millenium - a quiet exhaust is far more relaxing and less tiring when you drive long distances. OK - for just going down to the local shop, a bit of growl is OK (except for the local residents who have to endure such crap), but for a long (30 minutes or more likely 6 hours) drive, give me a silent car any day.

Another very good reason for keeping things quiet - you are more likely to be ignored by the boys in blue, than if you have a hoon exhaust. You may as well put a flashing light on your roof....

Plenty of threads about it, but the best free-flowing rear muffler for a 3rd gen is the Lukey LR2779.
It's essentially the same muffler as the factory Sports/VRX muffler.
Slightly sportier note than the stock muffler but not at all loud and no drone at all.
Quiet as the stocker when cruising, but as it's a 'straight through' muffler it frees up the exhaust system quite a bit.
It's supposed to be worth about 4 kw atw by itself, and it's what you need to take advantage of extractors.
If you want a lot more noise just remove the central resonator and replace it with pipe.
Next step is a hi-flow cat, maximum 200cpi. But combined with extractors and a free flow rear muffler things now start to get a lot noisier.
If you want increased performance with very little extra noise then go with extractors plus a Lukey LR2779.
Even then, extractors on a FWD 3rd gen don't achieve a helluva lot, as the existing exhaust manifolds are not too bad. Different on an AWD though, where extractors make a big difference.
In summary, the best 'bang for buck' mod is the Lukey LR2779 by itself...

I agree with treeAdy above.

I will say though that the HM headers I had fitted did clean up and improve the sound a fair bit.

So by fitting the Sports muffler the car gains 8kw, is this felt at all during driving, or does it feel faster because of the noise increase?

Does the Sports muffler add exhaust vibration into the cabin?
For example, sometimes when a Honda Civic overtakes me I feel the vibrations in my car from the Civics exhaust

Probably the best you'd do via a muffler change is to mirror the output of a VR-X or Sports setup which delivered 8kw more at the crankshaft (163kw vs 155kw) than a std Magna. Expect maybe 5kw more ATW - if you do it right. A set of headers might add a few kw more, but I don't know of anyone here who's done a before/after comparison on other than an AWD to demonstrate the gains. A 5kw (=5%) gain ATW would mostly go un-noticed under normal driving conditions.

Have changed from my "Expired" TH Executive 3.5 to a TJ Sports, it has the better engine - but also the free(er) flow -factory standard - exhaust - it has a much nicer gruff sound around town without being a drone at cruise.

loud enough to feel grunty but doesn't stick a big "I'm a dickhead" banner across your windscreen every time you stab the throttle like so many Hold'on Flogadore and Fooaaaard Failcon's floating around with straight thru's

I laughed so hard then hah