Pontiac Solstice Forum - View Single Post - Fujita intake, flawed design?

[quote=ender;507225]

Quote:

Originally Posted by jag767

The thing you're missing is the speed of the air at different points in the system. In a fat area, air will be moving slowly, while in a narrow portion, air will be moving more quickly.

Bottom line is: If the MAF is in a tube that's smaller than the stock location, air must travel past it at a higher velocity, fooling the computer into thinking more air is entering the motor than actually is (since it thinks that high velocity is in a larger tube). This could easily throw a code since the MAP sensor and MAF sensor are not agreeing with each other.

Russ

Everyone has good points and we all want to get to the bottom of the CAI issue. I would like to add some data to the discussion. When I had the CAI problem I also had the DashHawk installed and compiled a lot of data. Here are some insights:

1. Prior to setting the code the MAF sensor would show about 30% greater volume than the car now shows when it is running correctly. This was when the ECU was ready to set a code and go into limp.

2. As this took place the LTFT and STFT would both be driven up. When the combination of both hit a range of 20-25, the car would set a code or go into limp.

3. Multiple resets of the ECU did nothing until I cleaned the MAF sensor. I am not sure the air filter was the issue, but, if it wasn't, it was a dirty tube itself. In my case the problem was a contaminated MAF sensor that came from either the pipe or filter.

4. I have put on at least two thousand miles since the CAI issue and the LTFT now runs in the 0-3 range.

As far as the discussion relative to air flow and volume, everyone is right. The MAF sensor looks at velocity, but, the engine lives on volume (mass). A smaller tube might confuse the sensor, but, I don't see that now. On the other hand these engines are restricted by the factory airbox. It is strange the diameter would vary at the maf sensor location.

As far as intake air temperature, I can tell you this the Fujita CAI does not increase the IAT. At cruise there is only a difference of four degrees over ambient air temp and that is better than most cars. If someone has a Dashhawk and a stock airbox it would be interesting to see what that differential would be . One minor correction, the MAF and MAP sensors have no meaningful correlation prior to boost and that is where these codes are set.

Last edited by Jack B : 06-03-2007 at 09:06 PM.

	Jack B Member Join Date: May 2006 Location: NE Ohio	[quote=ender;507225] Quote: Originally Posted by jag767 The thing you're missing is the speed of the air at different points in the system. In a fat area, air will be moving slowly, while in a narrow portion, air will be moving more quickly. Bottom line is: If the MAF is in a tube that's smaller than the stock location, air must travel past it at a higher velocity, fooling the computer into thinking more air is entering the motor than actually is (since it thinks that high velocity is in a larger tube). This could easily throw a code since the MAP sensor and MAF sensor are not agreeing with each other. Russ Everyone has good points and we all want to get to the bottom of the CAI issue. I would like to add some data to the discussion. When I had the CAI problem I also had the DashHawk installed and compiled a lot of data. Here are some insights: 1. Prior to setting the code the MAF sensor would show about 30% greater volume than the car now shows when it is running correctly. This was when the ECU was ready to set a code and go into limp. 2. As this took place the LTFT and STFT would both be driven up. When the combination of both hit a range of 20-25, the car would set a code or go into limp. 3. Multiple resets of the ECU did nothing until I cleaned the MAF sensor. I am not sure the air filter was the issue, but, if it wasn't, it was a dirty tube itself. In my case the problem was a contaminated MAF sensor that came from either the pipe or filter. 4. I have put on at least two thousand miles since the CAI issue and the LTFT now runs in the 0-3 range. As far as the discussion relative to air flow and volume, everyone is right. The MAF sensor looks at velocity, but, the engine lives on volume (mass). A smaller tube might confuse the sensor, but, I don't see that now. On the other hand these engines are restricted by the factory airbox. It is strange the diameter would vary at the maf sensor location. As far as intake air temperature, I can tell you this the Fujita CAI does not increase the IAT. At cruise there is only a difference of four degrees over ambient air temp and that is better than most cars. If someone has a Dashhawk and a stock airbox it would be interesting to see what that differential would be . One minor correction, the MAF and MAP sensors have no meaningful correlation prior to boost and that is where these codes are set. Last edited by Jack B : 06-03-2007 at 09:06 PM.