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[cem_devecioglu]

http://www.youtube.com/watch?v=PCXzbzE1OSg

frank denkers calibra
http://www.opel-magazin.hu/en-autom/alomautok/52-calibra-v6-kompressor.html


500 hp

[Webby the Bear]

Thanks for all the input guys.

Are we saying that ''IN GENERAL'' NA cars don't have the meat n veg down bottom end to deal with any type of turbo coming in?

I can well believe it... I mean if it was meant to be turbo charged it wold have been. innit lol

[Marks DTM Calib]

Rarely the case actually, most engines are fine at the bottom end and the Omega, particularly the 3.2 is pretty strong.

The major issue is cooling and compression ratio in pretty much every case

When you use forced induction you get elevated cylinder temperatures and that heat has to be managed, this we know is the downfall of the Omega V6 in this scenario.

There are ways to manage it, oil squirters to cool the piston crown are easy enough to fit as are a few cooling modes to the coolant passages.

Similarly with compression ratio, forced induction increases the dynamic compression ratio and hence the static has to be reduced to compensate.

[The Sheriff]

Rarely the case actually, most engines are fine at the bottom end and the Omega, particularly the 3.2 is pretty strong.

The major issue is cooling and compression ratio in pretty much every case

When you use forced induction you get elevated cylinder temperatures and that heat has to be managed, this we know is the downfall of the Omega V6 in this scenario.

There are ways to manage it, oil squirters to cool the piston crown are easy enough to fit as are a few cooling modes to the coolant passages.

Similarly with compression ratio, forced induction increases the dynamic compression ratio and hence the static has to be reduced to compensate.

I was gonna tell him that but you beat me to it.....again. 

[Webby the Bear]

Rarely the case actually, most engines are fine at the bottom end and the Omega, particularly the 3.2 is pretty strong.

The major issue is cooling and compression ratio in pretty much every case

When you use forced induction you get elevated cylinder temperatures and that heat has to be managed, this we know is the downfall of the Omega V6 in this scenario.

There are ways to manage it, oil squirters to cool the piston crown are easy enough to fit as are a few cooling modes to the coolant passages.

Similarly with compression ratio, forced induction increases the dynamic compression ratio and hence the static has to be reduced to compensate.

Thanks Mark,

So, if I've got this right, as well as messing with the cooling and fitting extra cooling aids, the heads would need to come off to be skimmed or combustion chamber bowled out more to adjust the CR?

[Marks DTM Calib]

Various ways of doing it, dished forged pistons, thicker head gasket etc.....clearly skimming will increase the compression ratio not reduce it 

[omega3000]

Is 3.0 bottom end strong enough 

[Webby the Bear]

Various ways of doing it, dished forged pistons, thicker head gasket etc.....clearly skimming will increase the compression ratio not reduce it 

lol yeah sorry should have typed slower and read what I was putting 

So, my point being.... whatever way you wrap it up simply jamming a turbo on an NA car will require you to perform some internal mods even if the bottom end is up to the task of coping with it.

so, how would one choose a turbo? am I right in thinking that smaller ones create less lag as they spool up quicker but don't provide great boost at the top of the rev range and vice versa with big ones....

[Diamond Black Geezer]

No way an expert on this level of 'modding', however yes, that's the reason Lotus chose twin Garrett T25 Turbochargers for the Lotus Carlton - the idea being two little ones spool up quicker than one big one. Also take note of certain cars in production that have one tiny turbo and one larger one - for the same reason.

The general consensus is that supercharging the V6 is the best route, however, you must tread your own path; and I wish you best of success 

[Kevin Wood]

so, how would one choose a turbo? am I right in thinking that smaller ones create less lag as they spool up quicker but don't provide great boost at the top of the rev range and vice versa with big ones....

There are lots of sums to do to get the best out of it. It's easy to do badly and difficult to do well.

[cem_devecioglu]

personally I think even 6-7 psi turbo setup will be more than enough for daily use (for omega)
but even in that case the first problem you will face is injectors fuelling will not be sufficient
so you will need higher flow injectors( also you can use an adjustable fuel pressure regulator).. of course in that case the question is : will the pump be adequate for that rate.. and 3rd problem will be ecu..  it has to compansate increased air flow rate..  so you will need a custom programmed ecu (cheapest is megasquirt) .. 4th you will need intercooler to cool the heated compressed air.. compression ratio is not that criticial contrary to the general belief (if you wont go in high turbo pressures ) .. instead you have to deal with fuel air ratio (to control you need a wideband lambda) and change it drastically when pressure kicks in..  and you have to retard ignition from custom ecu which you cant with the stock one..


if you will go in that expense to turbo , than cooling can be solved with "some" investment   (in that supercharged calibra they cut slots in the block for better coolant flow )


but generally speaking it wont be cheap in any case

[Kevin Wood]

.. compression ratio is not that criticial contrary to the general belief (if you wont go in high turbo pressures ) ..

I wouldn't put even 6-7 PSI of boost into an engine with 10.8:1 compression (as in the X25/30XE).

[cem_devecioglu]

.. compression ratio is not that criticial contrary to the general belief (if you wont go in high turbo pressures ) ..

I wouldn't put even 6-7 PSI of boost into an engine with 10.8:1 compression (as in the X25/30XE).

ok.. whats the outcome of high compression on a boosted engine?  early ignition before spark.. and detonation..


this can be solved in several ways..  ignition retard, increasing fuel in air fuel ratio, cooling air by intercooler and water injection and lastly higher octane fuel


I have seen lots of audi turbos with 11.5 :1  ,  and also I didnt drop my compression ratio too..




if the car is equipped with a knock sensor , most stock ecus retard ignition to some extent.. of course if thats not enough you may use other methods.. at low boosts 10.8 :1  is not that problem


dropping the compression also has another disadvantage the car will need more boost to go..


I have seen 22 psi boost with stock compression

[aaronjb]

.. compression ratio is not that criticial contrary to the general belief (if you wont go in high turbo pressures ) ..

I wouldn't put even 6-7 PSI of boost into an engine with 10.8:1 compression (as in the X25/30XE).

You can have a reliable 250hp (30-40,000 miles) in the Toyota 1ZZ, that's 10.0:1 and 140hp standard.  OK so maybe adding a similar percentage if you start with 10.8:1 would be optimistic, but..

[cem_devecioglu]

I think thats a good reading about high CR


http://www.popularhotrodding.com/tech/0311_phr_compression_ratio_tech/