Compression check on 968
11-27-2004, 10:06 AM
#1
Racer
Thread Starter
Compression check on 968
Looking at the factory workshop manual I found a value of 8 bars (117.6 psi) for the compression check. The minimum acceptable value is 96 PSI. Looks to me a little low for a 11.0:1 compression ratio. May be this is due to the overlap induced by the variocam when deactivated. Can any one can confirm this, or has made a compression check? Thanks!
11-27-2004, 12:07 PM
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i saw that in the manual too - that is way lower than the readings i get - i have seen numbers from a few 968s i've tested, varying from 162 to 185 on my guage (which i now must check for accuracy) - what i have recently heard, is that it is supposed to be up over 200 when fresh - i have not been able to find the real spec anywhere yet, and hope somebody can find and post it
11-29-2004, 12:39 PM
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hmmm - looks like i may have a defective guage - time to check it with a known pressure
are there any abnormal test methods on this engine? typically i remove all 4 plugs, insert the guage and cycle 4 revolutions of the motor and take the reading, watching the guage each revolution
are there any abnormal test methods on this engine? typically i remove all 4 plugs, insert the guage and cycle 4 revolutions of the motor and take the reading, watching the guage each revolution
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11-29-2004, 04:49 PM
#8
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Angel, I see 190-195 on all cylinders on mine. Not sure if that makes it an average engine or a healthy engine. I think close to 200 shouldbe a decent number.
Aren't you planning running modded pistons anyway?How is the turbo coming?
Raj
Aren't you planning running modded pistons anyway?How is the turbo coming?
Raj
11-29-2004, 06:54 PM
#10
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normal is about 10 bars and above when new this is about 145 PSI to 160 PSI
8 bar is for worn engines
215 PSI is not possible
do not mix compression ratio and compression test numbers.
due to the heated air etc etc the 8,0:1 compression ration gives you baout 10 Bar compression numbers
Konstantin
8 bar is for worn engines
215 PSI is not possible
do not mix compression ratio and compression test numbers.
due to the heated air etc etc the 8,0:1 compression ration gives you baout 10 Bar compression numbers
Konstantin
11-30-2004, 09:53 PM
#12
Racer
Thread Starter
Raj;
My turbo project is going well. I already finished all the mechanicals. I'm right now tunning the Tec 3. I decided to do it myself. After all, I do all the conversion, including the Tec3 installation , so its me all the way. If something goes wrong, I'm the solely responsable. But so far everthing turns out very good. I'm very happy with the Tec 3 system. The programming and installation manuals are well documented, very clear and as simple as it can be. The datalogging feature allows me to run the car, then verify the data and make adjustments. I'm running less than 10 psi and the car feels very good, no detonation and good exhaust temperature. The coolant temperature does not rise over 90 deg which is very good taking into account the temperatures in Puerto Rico, which usually are over 90 Deg F. I'm using the vario cam system conected to one of the GPO (Spare) output channels. The next step is to optimise the Volumetric Eff. Table and put the EGO sensor in closed loop. Then a trip to the Dyno to tray to optimize the tunning further, specially the ignition timing and get some HP and torque numbers.
My turbo project is going well. I already finished all the mechanicals. I'm right now tunning the Tec 3. I decided to do it myself. After all, I do all the conversion, including the Tec3 installation , so its me all the way. If something goes wrong, I'm the solely responsable. But so far everthing turns out very good. I'm very happy with the Tec 3 system. The programming and installation manuals are well documented, very clear and as simple as it can be. The datalogging feature allows me to run the car, then verify the data and make adjustments. I'm running less than 10 psi and the car feels very good, no detonation and good exhaust temperature. The coolant temperature does not rise over 90 deg which is very good taking into account the temperatures in Puerto Rico, which usually are over 90 Deg F. I'm using the vario cam system conected to one of the GPO (Spare) output channels. The next step is to optimise the Volumetric Eff. Table and put the EGO sensor in closed loop. Then a trip to the Dyno to tray to optimize the tunning further, specially the ignition timing and get some HP and torque numbers.
11-30-2004, 10:27 PM
#13
Rennlist Member
Wow, that is awesome. Time flies. I remember when you were getting all the bits together. I am glad it came together for you. Hopefully I get to meet you someday in person. Alberto might be stopping over tomorrow. I am sure you know him as well.
Good luck and let me know if I can be of any help.
Take care.
Raj
Good luck and let me know if I can be of any help.
Take care.
Raj
12-01-2004, 08:42 AM
#14
Racer
Thread Starter
Raj:
Thanks very much for your interest. As you said has been a very long way. Two years and 4 months to be exactly. Yes I know Alberto, I visited him at his home to see the green 968T. I also saw the red 968 in track and the car runs very, very well. I look forward to meet you in person. I'll send you a PM with my contact info, so we can talk by phone.
Thanks very much for your interest. As you said has been a very long way. Two years and 4 months to be exactly. Yes I know Alberto, I visited him at his home to see the green 968T. I also saw the red 968 in track and the car runs very, very well. I look forward to meet you in person. I'll send you a PM with my contact info, so we can talk by phone.
