I have a question for anyone out there who might be in the know. What is the difference between the 163kw engine and the Ralliart 180kw engine? What did they do to give it an extra 17kw?

different, cams, pistion, exhaust and also computer

Different cams, 10:1 compression ratio (vs 9.0:1 in all other 3.5L's), different ECU tune, different exhaust headers.

Other notable differences include Koni suspension, vastly superior brakes, LSD fitted to manual models.

Different cams, 10:1 compression ratio (vs 9.0:1 in all other 3.5L's), different ECU tune, different exhaust headers.

Other notable differences include Koni suspension, vastly superior brakes, LSD fitted to manual models.
Actually 9.4:1 compression. Also don't forget the bucket seats and different exhaust system.

actually ralliart has 9.4:1 compression

engine has been re-worked with a high-lift camshaft, sports exhaust, new cylinder head, increased compression ratio, stainless steel exhaust headers and revised engine management calibration

The final iteration has an increased compression ratio (9.4:1 compared with 9.0:1) which was achieved by a reduced piston bowl depth while still maintaining top land height. This ratio was finally settled on, to ensure the car will give optimum performance on ordinary unleaded petrol. Higher ratios could have required the car to run on PULP which was considered undesirable.

An anodised piston crown and top compression ring land were specified to reduce wear and blow-by, while maintaining top end power.

The cylinder head combustion chamber was modified to reduce valve shrouding and improve breathing at small valve openings, thereby making full benefit of the 4-valves per cylinder configuration.

A high lift camshaft profile with 10% additional lift for improved top end performance was fitted. Although other camshafts which produced greater power were tested the deterioration in idle quality and exhaust emissions were considered unacceptable.

Special high lift valve springs, which have a unique cross-section to give increased clearance between coils at the increased lift, and are made from a special nitrided material for improved fatigue strength, are fitted.

The VR-X exhaust system, which was used as the base, was revised with the addition of a large bomb-type muffler to the centre pipe to improve the mid-high rpm exhaust note. After testing three alternative exhaust headers, specially fabricated stainless steel header pipes were added to increase top end power.

The engine ECU has also been remapped to:

-increase idle speed in "Drive" from 625 to 680 rpm to maintain idle quality,
-increase the speed limiter to complement widely available V-rated tyres (the car is fitted with 270 kph tyres),
-revise the spark map for optimal power with the increased compression ratio, and
-raise the air flow sensor map limit to accommodate the improved volumetric efficiency at high rpm,
-keep emissions within required limits.

The result is a very tractable engine at low revs, but which continues to pull past 6000 rpm without any effort. It is the type of engine that be run at low speed without any rough running and maintain good fuel economy. But if spirited driving is required the engine comes alive from 4000 rpm, giving the impression and performance of a much larger engine.

The enormous improvement in the top end engine breathing and mid range torque has broken through the limitations of the standard engine. Low speed tractability, a significant boost in mid range torque for acceleration, improved breathing at high rpm for extended high speed driveability, and a reduced need for gear changes under acceleration are all characteristics of this engine.

see this is why our ralliarts got 180, and the new aurion has 200kw. if they went the higher comp and slightly more aggresive cam profile the cars would of been over 200kw. at the end of the day a lot of effort went into the change between the two, and with no extra effort it could of had more power.

thanks mitsu big wigs :booty:

i reakon if the ralliart was 200kW....it definately would have more torque than the 336Nm that the aurion has (ralliart 333nm). Plus the ralliart can actually use that amount of torque earlier than the aurion

Awsome, thanks for that.

I've got a 163kw motor and was contemplating getting some engine mods if it wasn't too much work but after reading that I think it would probably be easier to just bolt on a supercharger.

sprintex supercharger

Sorry to thread mine, but you might find this interesting Mikeee:

http://autospeed.com/cms/A_1437/article.html

Sorry to thread mine, but you might find this interesting Mikeee:

http://autospeed.com/cms/A_1437/article.html

That's quite a good article. Interesting to note that the Ralliart cams were the biggest that they could physically fit into the heads...

interesting, but cams and exhaust for 7kw more? **** that! waste of money.

That's quite a good article. Interesting to note that the Ralliart cams were the biggest that they could physically fit into the heads...

That doesn't sound right, even the RPW "stage1" cams are hotter than the ralliart cams, which have the same duration as the rest, just a bit more lift.

EDIT: had a read of the article, which mentions ramp rates as the limiting factor?

Interesting article.
That's the kind of articles that people need. Ones that tell you want 'they' think can be easily upgraded/swapped from one model to another.

Another helpful link. http://autoweb.com.au/cms/A_55022/newsarticle.html

That doesn't sound right, even the RPW "stage1" cams are hotter than the ralliart cams, which have the same duration as the rest, just a bit more lift.

EDIT: had a read of the article, which mentions ramp rates as the limiting factor?

Hmm, I think it's just the way the article is written. Ramp rate is just how fast the valve opens and closes. The RPW cam spec list doesn't list ramp rate, just the usual stuff. It'd be interesing to see a cross-sectional diagram of std vs Ralliart cams.