Some interesting results were had today at a Dyno Power Run which i though i would share. As some would know my Ralliart has been lacking power to which was first thought to be a blockage in the exhaust somewhere (cat or muffler). Results were interesting.

With full exhaust - 119.2Kw ATW
With exhaust totally disconnected BEFORE cat - 121.1Kw ATW

Yes, it was damn loud but the mechanics said it sounded great to them straight out of the ralliart headers.

So for those with Ralliarts (maybe VRX & Sports also) you ARE wasting your money if you think changing the catalytic converter or muffler in order to gain more power. The figures shows a tiny variance of under 2Kw so keep your hard earned for something else!

Some interesting results were had today at a Dyno Power Run which i though i would share. As some would know my Ralliart has been lacking power to which was first thought to be a blockage in the exhaust somewhere (cat or muffler). Results were interesting.

With full exhaust - 119.2Kw ATW
With exhaust totally disconnected BEFORE cat - 121.1Kw ATW

Yes, it was damn loud but the mechanics said it sounded great to them straight out of the ralliart headers.

So for those with Ralliarts (maybe VRX & Sports also) you ARE wasting your money if you think changing the catalytic converter or muffler in order to gain more power. The figures shows a tiny variance of under 2Kw so keep your hard earned for something else!

As we have all said a hi-flow cat is only needed if your car has alot of mods otherwise you are throwing money away but having also said that if ya standard cat dies and needs replacing, ya may as well put a better one on.

It also proves what a well known engineer at MMAL once told me... To increase power on a Magna work on the intake, not on the exhaust (as RPW have done). The Ralliart exhaust seems to be very unrestrictive which is good.

the cat hi flow cat would have more of an increase if u had a good set of extractors to

There is still gains to be had with an exhaust system, whilst removing it completely may have little restriction, you are pretty much losing all back pressure which aint a good thing

Only 119kws ??

They have over 140kw standard, whats going on ??

Hmm... I would still think with pacemaker extractors, a straight through 2.5" system with a high flow cat you're going to see a lot more than 2kW. :nuts:

Only 119kws ??
They have over 140kw standard, whats going on ??

I know. As mentioned earlier my Ralliart has timing issues wheras the ECU is set to 10deg but the car insists on running at 6deg causing a big loss of power and with no simple explanation. I'm trying to find a Unichip to get this fixed.

Very interesting - I take it that you discovered this with a timing light?

Is the distributor OK - a unichip seems like a drastic step to fix it...

Cheers
Heath Young

The guys at the Dyno noticed the problem as they too were a little shocked at the low ouput of the engine. At the moment it is in the hands of the Ralliart Australia guru to work out how to fix it and then likely to install a Unichip for a bit more power.

Only 119kws ??

They have over 140kw standard, whats going on ??
it depends on the dyno dude .... at the last SA dyno an auto ralliart got 124 and a manual lightly modded got 134