VVT not working on Bugeye STi -Techie challenge?
30 December 2007, 01:43 PM
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VVT not working on Bugeye STi -Techie challenge?
I'm stuck,
Just replaced the 2.0Ltr STi with my06 2.5 STi engine complete, but kept the original ecu and wiring.
There were some issues, fly by wire throttle removed by using original manifold, this was better anyway as the 2.0 came without tumble valves.
Cam position sensors, these sense three holes on the 2.5 so the new cams were machined with the four pips (as on the 2.0) and the old cam position sensors used (on the back of the cams), This was relaively easy as the new cams have a larger diameter there. Also the front cam position sensor and pullies from the 2.0 have been fitted.
Here is where the problem may be and where I need help
The new engine had somehow lost its VVT cam drive solenoids (in the recycling yard!) and came with Identical ones to the 2.0 which actually don't fit because the mounting bracket is different I modified the fittings to allow them to fit properly.
On the dyno It seems the VVT is not doing what it should and I don't get the expected torque or hp. The boost and therefore the torque are slow to rise not doing much until 4000rpm when other 2.5 STi's with the same setup have the Torque right up there at 3200rpm. (decat 3" pipe VF43)
The question is whats the difference between 2.5 VVT Solenoids and 2.0 VVT solenoids appart from the slightly different fitting method?
Will a bugeye STI ECU drive the 06 2.5 STi solenoids? (I measured the 2.0Ltr ones at 7.3 Ohms ) Or is it something else thats causing the problem?
Apart from the lazy Tq curve and 55hp down on top end the car is running beautifully with noticably more off boost Tq than the 2.0
Can any one help?
Just replaced the 2.0Ltr STi with my06 2.5 STi engine complete, but kept the original ecu and wiring.
There were some issues, fly by wire throttle removed by using original manifold, this was better anyway as the 2.0 came without tumble valves.
Cam position sensors, these sense three holes on the 2.5 so the new cams were machined with the four pips (as on the 2.0) and the old cam position sensors used (on the back of the cams), This was relaively easy as the new cams have a larger diameter there. Also the front cam position sensor and pullies from the 2.0 have been fitted.
Here is where the problem may be and where I need help
The new engine had somehow lost its VVT cam drive solenoids (in the recycling yard!) and came with Identical ones to the 2.0 which actually don't fit because the mounting bracket is different I modified the fittings to allow them to fit properly.
On the dyno It seems the VVT is not doing what it should and I don't get the expected torque or hp. The boost and therefore the torque are slow to rise not doing much until 4000rpm when other 2.5 STi's with the same setup have the Torque right up there at 3200rpm. (decat 3" pipe VF43)
The question is whats the difference between 2.5 VVT Solenoids and 2.0 VVT solenoids appart from the slightly different fitting method?
Will a bugeye STI ECU drive the 06 2.5 STi solenoids? (I measured the 2.0Ltr ones at 7.3 Ohms ) Or is it something else thats causing the problem?
Apart from the lazy Tq curve and 55hp down on top end the car is running beautifully with noticably more off boost Tq than the 2.0
Can any one help?
30 December 2007, 02:19 PM
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For the vvt to work a number of conditions have to be met. When you are getting the car ready to do a dyno run, make sure you start the car and let it idle for 30 seconds before doing anything. Make sure the neutral position switch is working, the ECU needs to see the car is not in neutral before the AVCS will work.
Do you have deltadash or some other means to log the cam movements etc?
Do you have deltadash or some other means to log the cam movements etc?
30 December 2007, 03:00 PM
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Thanks for the reply,
Have enginuity log on Excell of the various runs on the dyno it shows some activity can email it to you if you wish, It doesn't mean much to me as I'm not familiar with what it should do.
Didn't know about the neutral switch, will check it s working.
Should I just buy the 2.5 type solenoids?
I seem to remember once reading that there was a recall on the original STi 7 ones but this is South Africa so the Subaru Importers would probably have ignored it.
Chris
Have enginuity log on Excell of the various runs on the dyno it shows some activity can email it to you if you wish, It doesn't mean much to me as I'm not familiar with what it should do.
Didn't know about the neutral switch, will check it s working.
Should I just buy the 2.5 type solenoids?
I seem to remember once reading that there was a recall on the original STi 7 ones but this is South Africa so the Subaru Importers would probably have ignored it.
Chris
