if i set my mixture and set my boost, then lean the car out, will the boost go up a bit. let's say 11.5 to 1 to 12 to one is the change at full boost. and my boost is almost 1psi higher?
also i have heard that the sr maf stops working properly at around 14 psi, but i have not had any problems. i am running about 14 and peak maybe 14.25. i am using an hks super afr to control my fuel setting.
boost & mixture in sr
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Nismo_Freak
- Posts: 10314
- Joined: Wed Jul 24, 2002 10:42 pm
- Car: 89 Nissan 240SX
The SR MAF will hit full duty at a slightly higher pressure on a larger T28 turbo, about the same point the injectors are at 100% duty. Only the T28 cars have issues with hitting limits.
A/F will not change your boost pressure, if it is increasing your boost pressure it's because the stock wastegate is crap and can't flow enough of the hotter gas.
This is a common issue on turbo RX7's where wastegate porting saves motors.
A/F will not change your boost pressure, if it is increasing your boost pressure it's because the stock wastegate is crap and can't flow enough of the hotter gas.
This is a common issue on turbo RX7's where wastegate porting saves motors.
Re: (Nismo_Freak)
i am using the hks adjustable actuator unit, it works well, but there is no electronic control. i was thinking that as you approach the best mixture for your motor, it would have the ability to produce a more powerful constant exhaust flow??? just thinking
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Nismo_Freak
- Posts: 10314
- Joined: Wed Jul 24, 2002 10:42 pm
- Car: 89 Nissan 240SX
Re: (gtune4)
No, the exhaust volume is mostly dictated by the latent heat of combustion and the reactant volume. When you run 14 lbs. in a relatively rich condition, ie. 10:1 you will have less pressure in the exhaust manifold. This gives more time for the wastegate to vent gasses because of the lowered turbine energy. When you lean out the mixture and get a hotter burn you end up doing the opposite. You increase the pressure in the manifold; giving the wastegate less time to vent, and in some cases providing more energy to the turbine which results in slightly higher than target boost pressure.gtune4 wrote:i am using the hks adjustable actuator unit, it works well, but there is no electronic control. i was thinking that as you approach the best mixture for your motor, it would have the ability to produce a more powerful constant exhaust flow??? just thinking
In severe cases like the FC3S RX7's you end up with 2-3 psi more than you wanted and it is one of the factors that makes the FC3S "unreliable" by opinion. Too many people got ahold of them like the DSM's and were running large amounts of boost pressure without replacing the secondaries (rotary), or providing adequate system efficiency.
Long story short, it's not out of the question to get the results you are getting, and if you are running the T25 you won't have an issue with the MAF or injectors until you upgrade your turbo.