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Author Topic: exhaust v6  (Read 4341 times)

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laney101

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Re: exhaust v6
« Reply #15 on: 07 May 2016, 07:15:06 »

Think im going to start small and see the improvements or lack off..

going to have new downpipes made with sports cats but leave the nice quiet system in place as condition is completely ok at moment.
complete full service
gearbox update via tech 2 (still cant find anyone local to liverpool)
remove excess pipe in airbox from bottom
and maybe get all injectors refurbed
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tigers_gonads

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Re: exhaust v6
« Reply #16 on: 07 May 2016, 19:31:51 »

Think im going to start small and see the improvements or lack off..

going to have new downpipes made with sports cats but leave the nice quiet system in place as condition is completely ok at moment.
complete full service
gearbox update via tech 2 (still cant find anyone local to liverpool)
remove excess pipe in airbox from bottom
and maybe get all injectors refurbed



Which v6 have you got fitted ?
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tigers_gonads

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Re: exhaust v6
« Reply #17 on: 07 May 2016, 19:57:03 »

Think im going to start small and see the improvements or lack off..

going to have new downpipes made with sports cats but leave the nice quiet system in place as condition is completely ok at moment.
complete full service
gearbox update via tech 2 (still cant find anyone local to liverpool)
remove excess pipe in airbox from bottom
and maybe get all injectors refurbed



Which v6 have you got fitted ?



Okay, now i've read the thread in full  ::)

Save your money and don't bother with sports cats  ;)
Get your hands on a pair of 2.5 / 3ltr cats, weld a pair of lambda bosses in to accommodate the extra sensors of the DBW engines and fit them to a new, standard cat back system  :y :y
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laney101

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Re: exhaust v6
« Reply #18 on: 07 May 2016, 20:34:41 »

Surely sport cats gonna be a lot better than two std cats ??

And to get good std cats probs cost just as much??

My original plan was to just fit 3.0 downpipes and move lambda but i thought for a decent price i can have atainless downpipes mandrel bend with two magnaflow 200cell sports cats in them.. why would this not be better??
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tigers_gonads

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Re: exhaust v6
« Reply #19 on: 07 May 2016, 21:27:18 »

Surely sport cats gonna be a lot better than two std cats ??

And to get good std cats probs cost just as much??

My original plan was to just fit 3.0 downpipes and move lambda but i thought for a decent price i can have atainless downpipes mandrel bend with two magnaflow 200cell sports cats in them.. why would this not be better??



I'm not really an expert in the dynamics of these engines but my opinions are those of a bloke who has owned both the 3lt and the 3.2  :)

Tuning wise, without forced induction (turbo or supercharging) there is not a lot more power to be gained but you can make them a little more driveable .

I personally prefer the feel of the 3ltr engine but if it did have a problem, it was with the downpipes which was cast not tubular and definitely was a choke point with the exhaust gasses.

The DBW engines cured this with tubular manifolds which are iirc good for much more then the 210 bhp ish that the 3.2 will kick out even on a good day so imho, i'd leave the standard 3.2 manifolds alone  :y

If you look at the physical difference between the 3ltr and 3.2 cats, you will see that the 3lt one is quite a bit larger then 3.2 one and is constructed must better so not only do they breath better but also last much longer too hence some lads on here (including myself) have modified the old cats to take both lambda sensors once the DBW pre cats start to fail and fitted them to our DBW engines ;)
I can confirm that it does make it a little more driveable  :)

Right, the DBW engines bad bits ...........
To get the DBW engine threw the yanks market emission tests, they have to choke it up with the precat and also reduce the compression  :(
If you remove the 3.2 heads and fit a pair of heads off a 2.6 c/w the 3.2 valves and do a little porting in the inlet manifold area, not only will you raise the compression back upto around the 3ltr but you will also have more torque due to the extra capacity and greater drivability of the larger and more solid cats  :y

I understand what you mean about the aftermarket sports cats but with the 3ltr cats been so durable, it isn't really a problem to use a pair off a scrapper and with the sensor bosses fitted, I would think it would be better in the long run  :)

Exhausts .........

I would say that the standard size one would be more then good enough for the amount of gas that the 3.2 will kick out.
Fitting a nice clean new cat back system will cost you about 100 quid so unless you really want to spend money on a stainless or to change the tone then i'd go down that route  :y
Also bare in mine that these engines do need a little back pressure to give maximum output and tinkering too far from the original setup will probably loose you some lower end torque which is the last thing you want on a 2 ton car  ;)
   
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YZ250

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Re: exhaust v6
« Reply #20 on: 08 May 2016, 09:59:56 »

Surely sport cats gonna be a lot better than two std cats ??
...............

Just something to be aware of, if your car was registered after 1st March 2001 the cats fitted to it must be type approved.
Boring info I agree, but not many sports cats are type approved and some are even stamped to make this clear.  :y
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TheBoy

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Re: exhaust v6
« Reply #21 on: 08 May 2016, 10:30:35 »

Lets take a step back, and ask the OP what he is trying to achieve, rather than 2nd guess :)

If it about durability and refinement, a known good (ETS or Eternal) will always be the most cost effective and refined option.

If its because itz well wicked to have stainless, coz itz where itz at, then its a rather pointless conversation...
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Re: exhaust v6
« Reply #22 on: 08 May 2016, 11:03:49 »

Does the post cat lambda sensor have any function in the UK? I have the impression it is usd in German MOTs as the emission measurement, and has no function in the UK.
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laney101

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Re: exhaust v6
« Reply #23 on: 08 May 2016, 15:25:34 »

I not changing exhaust manifolds and not mentioned changing them... there too much hassle invovled plus getting correct length primaries in such a small place isnt worth the cost of them. Plus most manifolds will alter power delivery where as standard ones are set to allow a flat torque curve across most of rev range so they are fine..

Cat back exhaust again i dont need a new one one thats one it completely fine not gonna swal for another md steel one... as in last post i decided might as well keep my system now as its quiet and works well..

3.0 downpipes yes i know are less restrictive one thwy have a smoother bend because of no pre cat and due to single cat is better designed.. however theu are all old now... so cats will be not as good as new plus most will be rusty not to mention hard to find.  Hence my reasoning behind getting a set of downpipes made with sports cats in them...

If i could find a good set of genuine 3.0 downpipes id fit them but not copys as copy cats are sh1 t .....

Head removal?? Where did thay come from never mentioned that at all.. this hread is about exhaust

Also i know not to vear to far from std port hence why when someone said fit jetex i said NO.... 2.5" bore on a twin pipe system to nig in my opinion ... on n/a anyways.
Hence my original question in first post what is std bire size and no one seems to know...


And when someone says withoit a supercharger or turbo theres not a lot of power to be had i say obviously not that into engine and tuning work...

Easy to get more power ... cams ..exhaust ..ported head... ported inlet... standalone management alter fueling and ignition ... .. cermaic coat valve train and pistons .. but this would shift power up rev range and takeaway from being a nice usable car hence why not doing it... plus cost

But i strongly believe derestricting the exhaust within reason shouldnt alter npise to much give better flow... have inlet and plenum ported and then maybe mapped..
Should see a good 20-30bhp which is only 10-15% increase but you will notice it. Same way you tell diffrrence between a 3.0 and 3.2

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Nick W

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Re: exhaust v6
« Reply #24 on: 08 May 2016, 16:40:29 »

The stock twin exhaust on my 3.0l is 52mm in diameter. That's pretty big for the 1.5 engine feeding each one! The chance of you liberating 20-30hp with your suggested 'de-restrictions' is very poor. I would actually want to see proof of such restrictions before going any further, all you're likely to do is to change the volume/tone of the exhaust. Getting that much power from an expensive aftermarket cam swap might be realistic on such a small engine.


I have 3.2 manifolds on my car, and they make a small but noticeable improvement to how the quickly the engine revs over 3500rpm, but I doubt there is any measurable extra power from them. I fitted them because they became available at a low price just before I lifted the heads to replace blown gaskets; having done that, the cost/benefit/hassle ratio doesn't justify the hassle of fitting them on their own.


The V6 is a carefully designed modern engine, made using high quality castings and machining techniques: most of the traditional porting procedures are redundant as there are no misaligned bores, steps, large valve guides, massive single-angle valve seats etc. Even the manifolds and plenum match effectively, so any improvements are likely to be small and come at the cost of of proper, time consuming  development rather than the  quick skim with a die grinder that makes such a difference to Mini engines(for example).


I would expect a fully developed 3.2 V6 with individual throttle bodies to make well over 300bhp, but with a ball-park cost of about 5000 it's never going to be cost-effective. Nor is it likely to be the sort onengine that would suit an Omega.
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laney101

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Re: exhaust v6
« Reply #25 on: 08 May 2016, 19:24:18 »

2" lovely that great to know. I wont be going bigger as that is pretty much spot on considering its a dual pipe system. if was converting to a single pipe system which im not 2.5" would be ok then hence not buying a jetex as 2.52 dual pipe system to big.

this is not a all singing all dancing engine and there is nothing on it that cannot be improved.(as with any engine) yes its modern and designed well.. but as with all engines its compromised for the global market. i work for jaguar land rover as a engineer and even our engines out the box could be improved as can fords ecoboost we use. they are made and deisgned to work well in all climates and meet all emissions standard for the market its sold in. not optimised for one place.

with throttle bodies yes you would see 300bhp no problem i believe But power would be shifted up range and it would alter characteristics of engine drastically to something i wouldnt like..

even on engines with three angle valve seats you can still improve them by altering the angle of each section and maybe placing in a 4th angle to move from stepped seats to pretty much round seats with very little flat on for valve.. this is all normal tuning practice depending on how fat you want to go..

the omega engine develops ok power standard around 217bhp. removing pre cats, and swapping 400 cell cats for 200cell cats would make a noticable improvement plus removing pre cats you alter the bend in downpipe allowing for smoother flow. doing this and then having it mapped to suit the altered exhaust you will see easily a 10% improvement over std power.

a good remap (i know omega is n/a so gain not big) to set fuel and ignition up for our climate and fuel plus mods to engine will see a few % on its own so couple that with a improved exhaust system(even fitting 3.0 downpipes instead of 3.2 downpipes) will see a improvement. not to mention the fuelling map can sometimes be a little lean top end you would gain there.

all little improvements add up. if i can gain 20bhp id be happy as previously stated a 3.0-3.2 is very different so little power increases you do make difference..




The stock twin exhaust on my 3.0l is 52mm in diameter. That's pretty big for the 1.5 engine feeding each one! The chance of you liberating 20-30hp with your suggested 'de-restrictions' is very poor. I would actually want to see proof of such restrictions before going any further, all you're likely to do is to change the volume/tone of the exhaust. Getting that much power from an expensive aftermarket cam swap might be realistic on such a small engine.


I have 3.2 manifolds on my car, and they make a small but noticeable improvement to how the quickly the engine revs over 3500rpm, but I doubt there is any measurable extra power from them. I fitted them because they became available at a low price just before I lifted the heads to replace blown gaskets; having done that, the cost/benefit/hassle ratio doesn't justify the hassle of fitting them on their own.


The V6 is a carefully designed modern engine, made using high quality castings and machining techniques: most of the traditional porting procedures are redundant as there are no misaligned bores, steps, large valve guides, massive single-angle valve seats etc. Even the manifolds and plenum match effectively, so any improvements are likely to be small and come at the cost of of proper, time consuming  development rather than the  quick skim with a die grinder that makes such a difference to Mini engines(for example).


I would expect a fully developed 3.2 V6 with individual throttle bodies to make well over 300bhp, but with a ball-park cost of about 5000 it's never going to be cost-effective. Nor is it likely to be the sort onengine that would suit an Omega.
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Re: exhaust v6
« Reply #26 on: 08 May 2016, 20:14:14 »

I think your calculations are very ambitious on a 3.2 without a fair bit of engine work or forced induction. The 3.0l may respond better to the mods, though it was built with less penny pinching to start with, hence being more powerful and more economical.
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Re: exhaust v6
« Reply #27 on: 08 May 2016, 22:57:00 »

Laney, top tip for more power is to use tesco momentum which is 99/100 octane. The knock sensors advance the ignition . 3.2 engines are not unduly restricted by the exhaust and cat. On a dyno you will see 230 - 235 on momentum.
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laney101

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Re: exhaust v6
« Reply #28 on: 09 May 2016, 04:32:00 »

i run super unleaded anyways all the time. but shell v-power. i know it automatically adjusts timing says in handbook :>

they may not be overly restricted but it still hasa terrible restriction at precat the bend isnt smooth in downpipe due to it. so i think 3.0 cat pipes be best found new type approved on on cat2you.co.uk 80quid each so thinking of buying them and welding in second lambda boss.

then going to look into recon injectors to make sure they are spot on...

then a possible remap
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Re: exhaust v6
« Reply #29 on: 09 May 2016, 08:14:59 »

i run super unleaded anyways all the time. but shell v-power. i know it automatically adjusts timing says in handbook :>

they may not be overly restricted but it still hasa terrible restriction at precat the bend isnt smooth in downpipe due to it. so i think 3.0 cat pipes be best found new type approved on on cat2you.co.uk 80quid each so thinking of buying them and welding in second lambda boss.

then going to look into recon injectors to make sure they are spot on...

then a possible remap

I'd be very careful fitting any aftermarket cat... Just because they're type approved doesn't mean they're any good ;)

That said, I've fitted cats from them to other vehicles before and they have seemed to be ok :y
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