Ls1 Exhaust Systems

[AngryRB]

So I just fitted a di fillippo 2.5inch twin system to a VU SS ute with ls1, everything else is stock..

The problem is its droning pretty bad on idle and upto 1500rpm, after that its very quiet but with a nice V8 sound coming thru, so I'm after any advice

on what to do with it. I just want a throaty, rumble without a drone , it sounds like an RB30 with no mufflers.

I've called the manufacturer and supplier, both say they've never heard of the system droning, so suggest it must be vibration of the body or touching something, well seems pretty good to me , i think its the rear resonator that maybe isn't doing much?

I have a few things in mind

1) replace rear resonator with a quality muffler like magna flow

2) see if an exhaust shop can make up a J pipe

3) add some 100cell cats and 2.5inch pipe from the manifold back,

4) the tail pipes are well over a foot long, should they be shorter?

Ive read all the commodore forums and nothing mentioned about this system except its the best etc...

[AngryRB]

anyone?

[Plattsy]

you have a cat at all?

[Ben C34]

When I bought mine it had an xforce system with 2 hotdogs at the back. Too loud especially at cruise Rpms.

Since putting in the cam (232 at 50) it was unbearable. Ended up squeezing 2 of these in at the back, not much room in a sedan, not sure if ute has more or less.

I welded the 2 mufflers together as they have to touch each other to fit. Massive reduction in volume

http://pages.ebay.com/link/?nav=item.view&id=171273988910&alt=web

[Ben C34]

Side by side on their edge at the back, if that makes sense.

Edited February 25, 2015 by Ben C34

[Plattsy]

i on the other hand had a redback cat back system.

it wasnt lousd enough so i removed the mufflers completely.

and cats.

i got around drone by adding kw.

music type.

[zebra]

The standard down tubes and cats will be part of the issue...also, the fact that those early LS motors have tiny cams, so don't sound real nice down low anyway.

[V28VX37]

Besides the cam high flow cats will make a big difference to the sound. It sounds like your system is a cat back only, correct?

I had full Di Fillippo 2.5inch twin system including headers and cats in my V2 Monaro and it sounded brilliant, much better than my R34

This was with a bigger cam and ported heads too so hard to say how much those contributed to the note...

EDIT: Also -> www.ls1.com.au

Edited February 25, 2015 by V28VX37

[AngryRB]

Its very confusing reading all the commodore forums, they all say this system is the best, so ive spent $800 thinking that it would sound nice and meaty, it does on the youtube clips,

the local supplier and the main business in Melbourne both say its very unusual and unheard of that the system would drone..

Ive had several opinions, probably all biased because they are business's that want some $$ spent at there shop.. they all agree that adding extractors and cats will make it worse and seem to think that the system is a rebranded redback system and just shit, the company says that's not possible as they only supply the "di fillippo" label to be welded to there system and cant be just bought and rebranded....

Ok so , latest word from the company is, " We have a VU ute here with same system and no drone or issue's, but first run the exhaust for 1000km's to "bed it in" and then let us know and we'll try to fix it".

so do you guys think, will this exhaust stop droning once it has done 1000km's?????

Edited February 25, 2015 by AngryRB

[Trex]

Once the packing in the mufflers bed in it will sound different, but not that different. Doubt it will happen in 1000k either.

Lol @ their response of never hearing one drone and blame fitment. So their exhausts have fitment issues?

Take a video and send it to them.

[AngryRB]

Ben- that looks like a good idea,

what did it sound like with them on the back? I still want the V8 rumble etc just not the drone, at the moment Its all engine above 2500rpm, which is almost silent.

Edited February 25, 2015 by AngryRB

[AngryRB]

Stegea97- at first it wouldn't fit up, but then I loosened the bolts on the cat pipes and manifold to cat pipes and it seems to bold up ok, but it does seem to hang quiet low at the rear, could do with being tucked up as theres almost a foot clearance above the rear resonator, as seen in pics.

[AngryRB]

If going with ben's idea, would a pair of Hooker 2.5inch mufflers sounds good without drone? look like a good bit of gear

[Ben C34]

I'm talking about the rear muffler, replacing that with two. Hooker aero chamber mufflers are sweet but wouldn't fit at the rear, and are slightly tricky to fit in the center of a commodore, as you really need offset in and out. And more expensive.

I'm surprised to see the exhaust uses slip joints at the back, that's a bit crusty. A proper bolted flanged connection like factory (and xforce ) is heaps nicer.

[AngryRB]

Do these engines need such large exhausts? a single 3inch on a skyline is enough for over 300kw's, the plan was to get the cat pipes and cats done next and then OTR plus tune and be happy with whatever that puts out, maybe 220-240kw's..

I have a single 3inch X force muffler that sounded good on the skyline, seeing as the rear muffler is so far back from the engine, would this work without

suffocating the flow?

Edited February 25, 2015 by AngryRB

[bozodos]

what is 'best' is mainly subjective, as is perception of drone. I have a twin 3" Xforce on mine with 100cpi cats, 4 into 1 extractors and a H type merge. Sounds good, but at 100km/h on a slight incline in 6th it will drone. I'm not worried because I generally turn the music up louder. Sounds great otherwise, and not insanely loud unless you stand on it.

You don't lose anything down low with bigger pipes, but you will gain a little bit up the top and it gives the LS a deeper note.

I wouldn't be f**king with a DF exhaust unless you already had cats and extractors and it still sounded crap. Bear in mind that you'll want a tune after that point.

Whatever you do' don't drop the rear resonator, it'll make it drone terribly. Remove centre mufflers if you intend on removing anything.

I also used to run no cat and a straight pipe on my Skyline though haha.

Oh and Commodore forums are pretty ordinary for the most part. Grumpy old men on LS1.com.au and mang machine warriors on JC.

Edited February 26, 2015 by bozodos

[AngryRB]

hmm, just took off the resonator off the rear, and Fark!!!! thing sounds like a V8 for the first time,

been told by local exhaust shop that its illegal and if i weld straight pipes to the back it will drone big time. arrgggghhhh!!!

[bozodos]

yeah that's why I said chop the middle mufflers if you must do any. Bear in mind that if you do change the cats and headers after that, it's going to be REALLY loud lol

[Ben C34]

Yep.

I forgot to mention mine has pacemaker 4 into 1 headers and some aftermarket cats. With 2 hotdogs at the rear was way too loud with the cam.

[AngryRB]

Question- If a 3inch exhaust can make 300rwkw's on Skyline, can an Ls1 make the same 300rwkws? if not how much?

Question- How would a Jap muffler, eg. HKS hi power silent with silencer sound on a LS1? same same or epic fail haha

Take into consideration that 250kw's is the target max power and just after a decent sound with no drone.....

Edited March 2, 2015 by AngryRB