18 replies to this topic

[Silent1]

So if Theoretically speaking here.... If i supercharged my NA with courtenays stage 2, what could i do from there power wise? say with another £3k? as i'd quite like nearer 300bhp just for the stupidity factor...

[Joe-Turbo]

dump the 2.2 and put in a 2.0turbo stage 4 in? may cost a bit more then 3k

[ChazUwe]

Well Courtaney are currently working on a Stage 3 conversion which will probably be approaching that figure. But this would clearly need internal engine work. I would imagine it would be alot more cost effective to get it all done in one go. Although no official details are available yet. Unlike some tuners Courtaney won't release details til they are 100% happy with it and finished the development phase. I am looking forward to hearing more about it myself

[Winstar]

So if Theoretically speaking here....

If i supercharged my NA with courtenays stage 2, what could i do from there power wise? say with another £3k? as i'd quite like nearer 300bhp just for the stupidity factor...

The std con rod are only rated to go to 250bhp, so courtenay keep the std rev limit as this then tops out at about 245 bhp.

Stg 3 is on the cards but will require a stronger bottom end and prob decomp pistons.

[vocky]

will 300 bhp ever be achieved

The reason that the #4 piston melts around 280ish is the supercharger itself. Most of the ppl that have blown up were running under 2.7 pullies which is simply way out of the specs for max rpm on the blower. Also many were careless and didnt upgrade the heat exchanger which is a virtual must when going smaller than the stock pulley as well as not taking advantage of water injection. Also blower porting for Stagmier (sp?) helps out a ton with IATs. Its also been confirmed that the intake manifold is poorly designed and flows significantly more air to the #4. This is why from the factory and with GM stage 2 they are pig rich, its done to keep things safe. Most of the folks with blown engines were running 11:8 or higher on air fuel. Obviously your wideband is a collective reading of all 4 primaries so you never realize theres a problem with an individual cylinder. The problem can be corrected with a stand alone that allows for different fueling per cylinder. Sadly thats just not something you can do with HP tuners

[slindborg]

have a look on the cobalt ss forums for what they do to the 2.2 in the US for fark all money... for the cost of the courtenay conversion you could have a stand alone ecu, a baaad ass steel bottom end, suitable head and knock out about 300-350bhp no worries.

[Winstar]

will 300 bhp ever be achieved

The reason that the #4 piston melts around 280ish is the supercharger itself. Most of the ppl that have blown up were running under 2.7 pullies which is simply way out of the specs for max rpm on the blower. Also many were careless and didnt upgrade the heat exchanger which is a virtual must when going smaller than the stock pulley as well as not taking advantage of water injection. Also blower porting for Stagmier (sp?) helps out a ton with IATs. Its also been confirmed that the intake manifold is poorly designed and flows significantly more air to the #4. This is why from the factory and with GM stage 2 they are pig rich, its done to keep things safe. Most of the folks with blown engines were running 11:8 or higher on air fuel. Obviously your wideband is a collective reading of all 4 primaries so you never realize theres a problem with an individual cylinder. The problem can be corrected with a stand alone that allows for different fueling per cylinder. Sadly thats just not something you can do with HP tuners

A major problem with root's type SC's are they are only about 60% efficient compared to Centrifugal compressors so your always going have heat issues if you try running them up to high boost levels.

Oh and the reason that cylinder 4 gets the most flow is because the flow exits a roots blower at around 60 degrees to the vertical, and the compact design of the manifold and the laminova CC cores means it doen's get chance to even out before getting to the ports.

[GunnerGibson]

phonenix are starting development of there supercharger soon.. using a rotrex s/c

[Silent1]

phonenix are starting development of there supercharger soon.. using a rotrex s/c

I'll be steering clear of that with a bargepole then. The reason being is a centrifugal supercharger is like a turbo but with a direct engine drive, they're old technology that was designed for engines like the WWII rolls royce merlin, As such they are really only efficient at high RPM and are designed to be held at a constant RPM.

Now if only someone will design one using a roots type supercharger

[VIX]

designed for engines like the WWII rolls royce merlin

Mmmm. A pity that won't fit ....

[Winstar]

I'll be steering clear of that with a bargepole then. The reason being is a centrifugal supercharger is like a turbo but with a direct engine drive, they're old technology that was designed for engines like the WWII rolls royce merlin, As such they are really only efficient at high RPM and are designed to be held at a constant RPM.

Now if only someone will design one using a roots type supercharger

Exactly why's that then?

The Rotrex have an epicyclic gearing system that acheives a high speed from a relatively low engine rotation speed. They are used on the Konigssegg and on some of the Honda R type SC conversions

And they are far more efficient than a roots or lysholm superchager, I should know they use our* Compressor Stages with the impeller modified to fit the gearing system.

* Cummins Turbo Technologies

[robfenn]

have a look on the cobalt ss forums for what they do to the 2.2 in the US for fark all money...

for the cost of the courtenay conversion you could have a stand alone ecu, a baaad ass steel bottom end, suitable head and knock out about 300-350bhp no worries.

I'm slightly confused with the whole supercharging thing. I was under the impression on here that our engines used a supercharger in the States and so we could simply order bits and fit it to our 2.2.

Upon looking it up though, 2.0 Cobalt is supercharged rather than the 2.2 version. So do you mean people are retrofitting a different supercharger or the factory one?

I won't get into the 'whats the best supercharger' debate but just to let everyone know GM uses the M62 Eaton which i believe is a roots type?

[slindborg]

GM did a retrofit S/C for the 2.2 as used in what they call the Cavalier. BUT the Cobalt forum has stacks of useufll info about all the engines in this family. you can order tha parts but the ECU is the killer sines their reflash isnt valid in the UK and we use the ETB whereas they use an MTB so we cant get an ecu from the US either unless you convert to MTB or make an ETB stand alone driver (im planning on this when I get a little free time)

[Exmantaa]

[/quote]

Exactly why's that then?

The Rotrex .....
And they are far more efficient than a roots or lysholm superchager, I should know they use our* Compressor Stages with the impeller modified to fit the gearing system.

* Cummins Turbo Technologies
[/quote]


The Lysholm twin screw is also a very efficient supercharger. (Also internal compression, not like a Roots which needs a plenum to compress in.) In the US some people are already changing the standard 2,2 SC for more efficient Lysholm type twin screws...

Roots: up to 12-13 psi max, higher and it becomes very inefficient (= blowing hot air)
Higher => go twin screw. But this has internal compression and is therefore at partial load less efficient.
(With a simple valve the roots can shortcut the plenum to the inlet and so work with almost no load. Good for road cars...)

[walkes]

why not just wire in a hair dryer or garden vack... superchargers are rubbish get a turbo

[Exmantaa]

why not just wire in a hair dryer or garden vack... superchargers are rubbish get a turbo

Hairdryer = centrifugal = turbo.....

Depends on what you want from your engine. High horsepower => go turbo
Throttle response => Nothing comes close to a well tuned NA engine with TB's. (= Expensive!)
A well done supercharger set-up is a good compromise i.m.o.

Edited by Exmantaa, 05 September 2007 - 09:53 PM.

[OC_Peter]

Hi Guys sorry to interupt, and pardon my bad Swedish School English, but isn't it a fact that the 2,2 litre n/a engine has a comp of 9,5 kg compared to the american SC engine that has 8,5 kg. If so I figure that either you will have to lower the comp or the S/C won't have any effect? Then again lowering the comp means replacing the pistons, the rods or some sort of spacer plate. Or I am completly wrong? BR Peter

[NickB787]

Hi Guys sorry to interupt, and pardon my bad Swedish School English, but isn't it a fact that the 2,2 litre n/a engine has a comp of 9,5 kg compared to the american SC engine that has 8,5 kg.

If so I figure that either you will have to lower the comp or the S/C won't have any effect?

Then again lowering the comp means replacing the pistons, the rods or some sort of spacer plate.

Or I am completly wrong?

BR
Peter

Your right the 2 choices are puting 8.5 pistons in or using a double stack head gasket. ( as I have at the moment). I am in the process of a new build with 8.5 pistons and eagle bottom end and let Courtenays sort the rest out.

[slindborg]

I was told a spec using 10:1 compression ratio and you put the boost in later when the volumetric efficiency has dropped off to get the power back.... its a well known method. Big "boost" Late in the power curve and high compression ratio so bottom end power isnt compromised. or Lower CR and you can run more boost everywhere but throttle response is a little ropey.. boost can be controlled on S/C's fairly well with clutches etc.