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[stuvaux]

has anyone got any suggestions for tuning a 2.5V6?

i have lpg fitted, so fuel related mods are not much good

also, i have limited funds at the moment, so the cheaper the better ideally!!!

thanks,   stu 8-)

[omegaV6CD]

Full detailed service is the first step, 3lt cams the second step as they should give you 20ishbhp extra.
Mtek performance chip is highly recomended on this site.

[zealious]

What are these things I hear about mtk performance chips? i was always under the impression that they are bad for the car?

Anyway I have heard a lot of good things about having fuel injectors cleaned and flow tested. for as low as 12USD per injector, they will be tested, cleaned and then tested again. Its def a good place to start. Ive been interested in cams for my 3.0 but my issue is the fact that the engine already produces high rpm horse power , I want more lower end tq wille not loosing any of that HP in the higher ranges. If anyone knows of a good cam for this pls let me know.

Get a shop to polish/terbulance ur intake and then the same to exhaust. Bore if you can.

If you got the bux why not get your whole head flowed. any most bang for buck things are usualy cams and chips.

[rhydV6]

3.0 Cams, Decatted Exhaust, Remap (e.g Courtney Sport), Decent Induction setup, 4 bar fpr, lightened flywheel and a well serviced/maintained engine

Also the 2.5 is only good for about 205bhp max on standard internals iirc

Expect to achieve about 200bhp on the above mentioned mods

[Marks DTM Calib]

3.0 cams.....and a dam good service.

The V6 engine bottom end is good to very high levels of bhp (note, the 2.5 and 3.0 are pretty much the same with just a different stroke and bore) and teh ehads aer pretty free flowing. The 3.0 gets sodium exhaust valves which in theory helps with heat removal but, at higher bhp (250ish) the unit struggles with cooling problems around the heads. I suspect this can be overcome by replacing the water to oil heat exchanger with an air one and modifying the coolany feed so it enters the centre of the plate rather then the back of the block.

The you you should be able to turbo/supercharge.

[Admin]

Best improvement that can often be made is a really good servcing schedule.
Very regular oil and filter changes.
Check/replace spark plugs.
Make sure your crankcase breather system is completely clean!

Fit a set of 3.0 cams (£100). This is by far the single best upgrade you can do.

Fir an Mtekperformance chip (£140ish) and you will have around 200bhp (and a healthier bank balance!).

Don't get me started on people like Courtney!...

Decent induction setup is pretty much pointless unless you want the extra noise. No performance benefit.
Fpr. May help a little, but not worth the cost.
Lightened flywheel? It's dual mass for a reason so you lose smoothness (and significant contents of your wallet!) in transmission of power for a more free revving engine.
Decatted exhaust... sorry I think that is a waste of money. The restrictions are  the manifolds, not the cats.
As for the remap... just go with the Mtek chip.

Ultimately though, if you want performance, go get a turbo charged car. The Omega is a smooth cruiser, and at that, it excels!

[rhydV6]

Best improvement that can often be made is a really good servcing schedule.
Very regular oil and filter changes.
Check/replace spark plugs.
Make sure your crankcase breather system is completely clean!

Fit a set of 3.0 cams (£100). This is by far the single best upgrade you can do.

Fir an Mtekperformance chip (£140ish) and you will have around 200bhp (and a healthier bank balance!).

Don't get me started on people like Courtney!...

Decent induction setup is pretty much pointless unless you want the extra noise. No performance benefit.
Fpr. May help a little, but not worth the cost.
Lightened flywheel? It's dual mass for a reason so you lose smoothness (and significant contents of your wallet!) in transmission of power for a more free revving engine.
Decatted exhaust... sorry I think that is a waste of money. The restrictions are  the manifolds, not the cats.
As for the remap... just go with the Mtek chip.

Ultimately though, if you want performance, go get a turbo charged car. The Omega is a smooth cruiser, and at that, it excels!
 

Thanks for the dig at my post...

Induction plays a massive part. Standard vectra v6 made standard figures with k&n fitted, rig up a good cold air feed to that and it made 12bhp more - proven by back to back runs on the dyno.

CAT is more restrictive than a straight piece of pipe - end of discussion on that one.

More free revving engine is important for better acceleration, tbh who cares about fuel consumption on these cars? You'd own a diesel if you're that bothered.

FPR is £50 hardly expensive, well worth it if you've fitted 3.0 cams and chip/remap imo

[theolodian]

Everyone has their own opinions.  Induction gains vary from car to car even with the same engine, 12hp is not unusual if the original is a restriction.  However, also easier to lose hp than gain with an induction kit.  Manufacturers' claims are useless.

Cat restriction again depends on car.  Clogged cats are always a problem, however standard cats often aren't a huge loss on non-turbo cars.  I think it is always better to leave the cats in if you can.  Can have unintended consequences with the exhaust note/booming.

FPR can give small a benefit to fuel economy, due to better atomisation, and support gains from cams, etc.  Best if chip/remap is set for new FPR.  Will throw off trip computer.

A big car like an Omega isn't going to see the same benefit from a lightened flywheel as a lighter car.  It also degrades the comfort, especially if replacing dual-mass, which is what an Omega is more about anyway.

In short, the only sure route is to listen to people that have done things to the same car you have, and hopefully have RR results to prove it.

[rhydV6]

Everyone has their own opinions.  Induction gains vary from car to car even with the same engine, 12hp is not unusual if the original is a restriction.  However, also easier to lose hp than gain with an induction kit.  Manufacturers' claims are useless.

Cat restriction again depends on car.  Clogged cats are always a problem, however standard cats often aren't a huge loss on non-turbo cars.  I think it is always better to leave the cats in if you can.  Can have unintended consequences with the exhaust note/booming.

FPR can give small a benefit to fuel economy, due to better atomisation, and support gains from cams, etc.  Best if chip/remap is set for new FPR.  Will throw off trip computer.

A big car like an Omega isn't going to see the same benefit from a lightened flywheel as a lighter car.  It also degrades the comfort, especially if replacing dual-mass, which is what an Omega is more about anyway.

In short, the only sure route is to listen to people that have done things to the same car you have, and hopefully have RR results to prove it.

Yes all good, can't beat a good sounding exhaust note!

My drilled airbox sounds great too, nothing better than hammering up behind someone and booming past them on the open road

Sorry for my opinions as they're clearly off the 'norm' for this site, but I am 23, have owned tuned astra GSi's and GTE's before this, and have bought the omega as a fast family car (as I have a 2year old son), so when I'm in it on my own speed is of the upmost importance. Until I have 200bhp I won't be happy with it, as it's horrendously slow at the moment. Any gains I can get, however small are important to me.

It will also be visiting the 1/4 mile strip and track days in the future so acceleration is also very important to me.

LSD will be fitted soon too.

I'm not a 50+ year old who needs a comfortable and quiet cruiser.

And fuel consumption is not important to me at all.

[Marks DTM Calib]

Thanks for the dig at my post...

Induction plays a massive part. Standard vectra v6 made standard figures with k&n fitted, rig up a good cold air feed to that and it made 12bhp more - proven by back to back runs on the dyno.

CAT is more restrictive than a straight piece of pipe - end of discussion on that one.

More free revving engine is important for better acceleration, tbh who cares about fuel consumption on these cars? You'd own a diesel if you're that bothered.

FPR is £50 hardly expensive, well worth it if you've fitted 3.0 cams and chip/remap imo

The Omega already has a very good cold air feed from just behind the grill, a panel filter may make a bit of difference but, in reality the standard filters have a massive surface area and will give just as good a performance as most panel filters.

The cats is a tough one and you need to get your head around valve overlap etc to fully understand why some engines do benefit from some back pressure. The big erea of concern on the Omega is the exhaust manifolds, they are not good.

A lightened flyhweel will not add extra horse power, it might allow the engine to rev a bit easier but thats it adn given that you need to drop the box off and fit a totaly different flywheel and clutch setup. If this is realy of interest then fit a lightened pulley first as its much easier and can be sourced cheaply by getting one form a 2.6/3.2 (much less than a ton new) as these are pressed steel.

A FPR might help but, reality is that if your getting to the point where you need one then your injectors are to small.

[Admin]

Everyone has their own opinions.  Induction gains vary from car to car even with the same engine, 12hp is not unusual if the original is a restriction.  However, also easier to lose hp than gain with an induction kit.  Manufacturers' claims are useless.

Cat restriction again depends on car.  Clogged cats are always a problem, however standard cats often aren't a huge loss on non-turbo cars.  I think it is always better to leave the cats in if you can.  Can have unintended consequences with the exhaust note/booming.

FPR can give small a benefit to fuel economy, due to better atomisation, and support gains from cams, etc.  Best if chip/remap is set for new FPR.  Will throw off trip computer.

A big car like an Omega isn't going to see the same benefit from a lightened flywheel as a lighter car.  It also degrades the comfort, especially if replacing dual-mass, which is what an Omega is more about anyway.

In short, the only sure route is to listen to people that have done things to the same car you have, and hopefully have RR results to prove it.

Yes all good, can't beat a good sounding exhaust note!

My drilled airbox sounds great too, nothing better than hammering up behind someone and booming past them on the open road

Sorry for my opinions as they're clearly off the 'norm' for this site, but I am 23, have owned tuned astra GSi's and GTE's before this, and have bought the omega as a fast family car (as I have a 2year old son), so when I'm in it on my own speed is of the upmost importance. Until I have 200bhp I won't be happy with it, as it's horrendously slow at the moment. Any gains I can get, however small are important to me.

It will also be visiting the 1/4 mile strip and track days in the future so acceleration is also very important to me.

LSD will be fitted soon too.

I'm not a 50+ year old who needs a comfortable and quiet cruiser.

And fuel consumption is not important to me at all.

No offence intended and please continue to express your opinions. Debate is alsways good.

I am a little perplexed on your choice of car. If you want impressive performance, why have you bought a 2.5 Omega?
It is a very good car and does the job it is designed for very well.

Alas, the Omega (maybe with the exception of a manual MV6) is not designed to be a really fast accelerating car.
If you want that, you really want a turbo charged car, which is also easier and cheaper to tune (as I am sure you well know).

Honestly, the best improvements will come with the 3.0 cams and an Mtek chip. These 2 will cost you around £250 and take it up to around 200bhp.

After that it really does get expensive for only small gains I am afraid.

[Marks DTM Calib]

If you want a fast accelerating car you want a big V8....Turbos realy are a tuning compromise not an out the box choice for fast acceleration as they dont deliver flat torque delivery.

[Admin]

Got to agree there.... especially if it happens to be called Monaro!

However big V8s are thin on the ground and generally bl**dy expensive.

[rhydV6]

Turbo's are unreliable - not interested in a tuned c20let, even with it on Ph2 or Ph3.5 as the engine is basically a turbo'd XE - which is a pants engine.

And what family car are we talking that's turbo'd and fast? Old Cav-T lol?

As I said I wanted a 'fast' and reliable family car, ok so an MV6 was at the top of my list but cash at the time and the fact that this bargain popped up I settled for a 2.5 one.

Already listed the mods I will do, alternatively I will sell this and buy an MV6 manual, as the lack of lsd and outright power on mine is very disappointing

[Marks DTM Calib]

To be honest, the Omega is well enough balanced so that the LSD does very litle unless its mega slippy...