Scorpion, AusS2000 , thank you for the infoand ur time.

 

[sittingonedgeofseatwaitting]

Thanks for the info, it has sunk in. How about Chapter II?

[/sittingonedgeofseatwaitting]

 

Yes, absolutely! How about chapter 2? This is one of the reasons this site continues to be the benchmark of car forums. Intelligent members who are willing to share their knowledge. Much appreciated.

Erick

 

Well AusS2000 touched a bit on wstegates and solenoids But since I spent the time typing it up here is the rest on boost control.

Boost Control

OK so we are running FI, but how much boost do we have? How much boost do we want? For a supercharger this is easy. If we want to run 9psi of boost all we have to do is buy a pulley that will spin the compressor fast enough at a 9000rmp to make 9psi. A turbo is a bit more complicated to control boost on. Because it uses exhaust gas to spin the turbine, we need to regulate the amount of pressure that flow into the turbine housing. This is what a wastegate does. I

 

That's exactly what I was trying to get at. You are correct in that the fuel supply line to the rail and injectors is not touched.

 

Ahhh my old friend the EGT gauge. There are a lot of misconceptions about what they tell you and how they can be used for tuning. Let's look at some myths.

1. I can use my EGT gauge to tune my AF ratio.

LOL that's my favorite one. Yes you "can" use it to tune your AFR but I highly discourage it. Lower AFRs will give you a lower reading on EGT and higher AFRs will give you a higher reading, so in a sense you can adjust AFR to get a target EGT reading. But here's the kicker. Timing also plays a big part of your EGT readings. Too much advance and you will have a high reading no matter how much fuel you add. Same is true if you cut timing, no matter how much fuel you cut, you will get lower reading. EGT can only be used to set AFR IF and I mean IF you have your timing set perfect.

2. I can use my EGT gauge to tune timing.

See above

3. My EGT gauge will tell me that my engine is about to melt and I can stop the car before it happens.

Not true. Stick a thermometer into a boiling pot of water, how long does it take the thermometer to show the correct temp? Same concept, by the time you get the reading (and this is only a second or two) you have already done damage.

Those are the things that stick out most to me about EGT. Don't get me wrong, I have an EGT in my car. But I use it just like I use my other gauges. If the car is running right I don't even look at it. When I am tuning I look at it to make sure that I am within a range of "comfort". If I'm not that something is wrong with the tune and needs to be addressed.

As far an installation, it can be tapped anywhere into the exhaust. But remember that the closer you get to the head the better your readings will be. Most turbo guys I know tap it into the number one exhaust runner. Others do it at the beginning of the downpipe.

 

im considering the AEM EMS with GM solenoid. could we touch more on that? im very far away from any tuner and wondering if all tuners are familiar with this concept of boost control? so i dont have to make numerous drives to the tuners to get it retuned etc...

 

what kind of pressure is seen inside the supply line from the FPR to the FMU? On a stock vortech kit w/ 10:1 fmu would it be seeing the full force of the FMU and fuel pump somewhere in the area of 125psi?

 

The reasoning is on a mass air flow metered system the air is measured shortly after it passes through the filter. When blowing off excess air in between shifts that air that was measured is lost and the system is still providing the fuel for the air it measured. This can cause a flame out the rear On some cars it even causes it to stumble and fall on its face. HKs and other aftermarket companies make electronic gadget that sense these conditions and try to compensate. Sometimes it works. The best bet is to resurculate this air back in after the mass air flow meter so it can be used but the delay in the pressure saves the turbo.

In very rare cases a mass air flow metered car is setup in a blow through fashion where the air is measured shortly before it enters the throttle body. With these systems the blow off valves do not effect the system because the air has not been measured yet.

On a map based system the blow off valves don't need to recirculate because the air is measured in the intake manifold.

The best way to deal with this excess air is to blow it off into the atmosphere. The reasoning is to reduce the intake air temperature. With a recirculation type setup the air that was compressed using the supercharger or turbo is rerouted back into the system. This means you are putting hotter air back in the system to be heated back up again.

BOV placement. The best spot for the bov is close to the throttle body. This allows the sudden surge to open the valve quickly before the turbo sees it. This was the whole point in the first place. Back pressure on the turbo or sc can slowly damage the unit and on a turbo system it slows down the spool between shifts.

J

 

knowLedge


BTW, if you can't afford an EMS or at the least greddy e-manage, don't turbo this car unless you've tuned other cars with weak tools like the s-afc.