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MG MGF Technical - Mazda mx5 lack of reving


A friend of mine has a Mazda mx5 1.8 liter mk1.
Hes having some doubts, whether it is normal or not that his engine lacks power on high revs (+6k RPM).
The engine pulls strong until 6k RPM, then the engine suddenly looses power very quickly, even going downhill.

Can anybody advice on what to do (maybe Mike Satur) ?

1.8 16V
130 bhp
Timing adcvanced to 13
Standard exhaust w/cat
Standart Airbox with K&N + cold induction home made pipe, collecting air from left headlight

This topic is here because Mx-5 BB sucks, and there are no experts according to him.
Bruno V.

Buy a new MGF!
Don Liang

I hate miata's :) Seriously, though, you should get better answers on other boards. Solving performance engine problems really needs alot more info than you provide and therefore alot of testing. How much power does is lack? Engine run perfectly otherwise, with no check engine light? Even so first order is to pull any codes/data from computer memory and work from there. If all checks out, you'll need to use a scope and possibly a dynomometer to check ignition and fuel parameters as revs climb. However, high, sudden or prolonged high rpm testing on higher migeage engine could prove disasterous. Good luck.

From the description given, it sounds as though a governor is kicking in at 6000 rpm, probably electronic. As an aside, most Japanese engines have excellent mid range power (2000-5000 rpm) and little is to be gained by not shifting to a higher gear at about 5000 rpm unless the only intent is to create noise and additional engine wear.
George B.

Sudden power cut off is a common symptom that you get when the exhaust system, inc cat, reaches it's max flow, and from there becomes 'congested'. The effect is as if someone builds a wall through which it is impossible to drive through, although you will be able to 'free rev' the engine through it, since when not under load there is far less exhaust gas volume.

This is a symptom that can affect ANY car and with cats it is likely to be a 'when' question for many.

Roger Parker

My friend Rui Monteiro asked me to give special thanks to everybody who helped him in his quest. The Cat will be removed next week...and the exhaust manifolf (headers) will be ordered soon.
He havenīt decided yet between Supersprint or Moss...
Bruno Valadas

This thread was discussed between 21/04/2000 and 24/04/2000

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