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Boost issue in 5th gear 100kph

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Boost issue in 5th gear 100kph

Postby tonkamu » Fri Sep 22, 2017 9:30 am

Not sure if this is an engine or drive train question. I'm running 15-17 PSI, 2'5" exhaust and fuel increased my car is 2.8.

On the motorway I see constant 7-10psi on flat road cruising along in 5h gear doing around 90-100kph, if I slightly accelerate it will boost to 15-17 psi until I ease off to keep a regular speed & boost hovers around 10psi. Its like its always loaded in 5th gear at highspeeds, I've had this problem with 31 inch wheels aswell. Could someone shed some light on this?
tonkamu
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Re: Boost issue in 5th gear 100kph

Postby geeves » Fri Sep 22, 2017 10:55 am

Thats called normal
Boost is developed by exhaust flow which is affected by fuel use engine speed etc. Cruising at 100kph you have a fairly high engine speed but low fuel use so there is not enough exhaust flow to give full boost not that you need it in that situation. put the foot down and for the same engine speed you have more fuel so more exhaust flow so more boost
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Boost issue in 5th gear 100kph

Postby tonkamu » Fri Sep 22, 2017 1:40 pm

Oh ok cool, so cursing with 10psi for long period of time isn't wearing anything out?
tonkamu
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Re: Boost issue in 5th gear 100kph

Postby geeves » Fri Sep 22, 2017 4:40 pm

no racing with it at 17 is though
Sanding your knuckles before starting work can help. That way you cant skin them
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