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this is how it works

you get to choose from

Fast

Reliable

Cheap

Pick two.

Fast + Reliable = Not Cheap

Fast + Cheap = Not Reliable

Cheap + Reliable = Not Fast

lol

I always thought that people blow rotaries because of modding without a tune? Because they are MAP based arent they? So adding free flowing exahausts, intakes, intercoolers etc and not compensating for the extra airflow = lean. Bang?

  • 2 weeks later...

Not necessarily so, my (work) holden rodeo ute pings badly in the upper rpm when i floor it and it has 230, 000 ks on it, has been doing it since I first started driving it at 70, 000ks

Not necessarily so, my (work) holden rodeo ute pings badly in the upper rpm when i floor it and it has 230, 000 ks on it, has been doing it since I first started driving it at 70, 000ks

because race car...sorry I mean because Holden...same thing really :P

because race car...sorry I mean because Holden...same thing really :P

Nah, the only holden thing on it is the badge

All isuzu running gear, cant adjust the timing on

tthe bastard , its only the 3.5 litre that does it, the

3.2 litre doesnt do it

Edited by StevenCJR31

detonation (ping, knock etc), as a general rule, is only highly destructive on a motor depending on its power output per cc (engine size). Basically because for higher output per cc you need a bigger, more powerful combustion charge (and usually compression) so if this charge detonates (pings) the cylinder pressure is waaay higher (and usually hotter) than a detonation in a motor with lower power per cc. Hence why old clunker, low power reliable cars can have detonation and not get upset and live a long time. While you have detonation in a high output motor, esp a boosted motor (very high output per CC) it will kill it quick.

Having said all this, im not sure what detonation would do specifically on a rotary motor to hurt it as I don't know enough about them.

all I know is that they sound sick and can run an epic 1/4 :P

The rotary combustion chamber behaves nothing like a piston engine, hence detonation is almost a non-issue on rotaries (apart from highly boosted rotaries). The volume in the combustion chamber increases rapidly at the beginning of the power stroke due to the nature of the epitrochoidal motion of the rotor. A piston engine's combustion chamber volume increases very slowly at the start of the power stroke, meaning that any pressure spike can have adverse effects on the piston engine.

This phenomenon means that it's much harder to induce detonation in a rotary engine, as the volume increases at a rate where the effect of pressure spikes very much reduced.

NA rotaries generally don't suffer from compression related detonation, and in fact anyone using anything more than 91 octane in a NA rotary is most likely wasting money. Turbos, on the other hand, - well, turning up the wick too much can destroy any engine.

Like any engine, a properly maintained (and sensibly modded) rotary will last a very long time. The last gen RX7's are a fantastic package, and sure to impress. Like with any 20 year old performance car, you can expect to see a lot of badly maintained ones, which will be lemons. No worse than any other performance car of the same vintage though.

Edited by warps

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