Can the VVT work on/off with a simple switch/relay ? Or does it need PWM? Is it just like +12 or +5v and it works?
__________________ New 2010 project (click image)
1994 3100 BERETTA. 200,000+ miles
16.0 1/4 mile when stock. Now ???
Original L82 Longblock with LA1, LX9, LX5 parts
Manifold-back 2.5" SS Mandrel Exhaust. Hardware is SS too.
Can the VVT work on/off with a simple switch/relay ? Or does it need PWM? Is it just like +12 or +5v and it works?
i think it works on oil pressure, and i think its progressive. dont know what it takes or how it works. id be interested in knowing though
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87 fiero gt 5spd 3500, 1280 cam and PR, ls6 valve springs, port and polished heads, ported lim, ported uim, 4.3 70mm tb, ported trueleo headers and y pipe, 2.5 inch ex, flowtech muff, gmtuners.com prom, 7730 ecm (GAVE TO BROTHER, divorce reasons.)
96 LT4 6spd corvette. 4:10 gears, Open element intake, pcm4less tune, hurst short shifter, muff elims,
94 geo metro, 1.0l 3cyl gas sipper. scariest car I have ever driven!!! slow, ugly, slow, cheap, slow, handles like a wet noodle.
Can the VVT work on/off with a simple switch/relay ? Or does it need PWM? Is it just like +12 or +5v and it works?
PWM would be proper for it but without the OE PCM to operate it on/off would serve the same purpose with less resolution in between since instead of a gradual change in cam position over the rpm it would just switch from low range rpm to high when retarded.
It would have to do this at the same rpm point everytime otherwise it would throw the tune off since the older ecm can't correct for VE in the event phasing stops working and the cam remains advanced at a point where it's supposed to be retarded at say the midway point of the rpm range, VE above that point would be very poor if the cam did not retard to increase upper rpm efficiency to match what it was initially tuned for when working as intended. In stock form if the VVT stopped working hp output would be greatly reduced.
I didn't have the room I thought I would for the intercooler and water injection is just as good so I took that route.
The last test drive was much better and still suggestive of the spark table needing to be a little more aggressive, I added about 2 more degrees but didn't datalog to check for detonation this time since the 93 should be good enough for 7psi. Running on 93 octane may have a lot more to do with it at the moment not having detonation. It barely saw 7psi under full boost so hopefully it's efficient enough to run 7psi on 87 octane which will leave a lot of room for higher boost eventually 12 psi which should really make the 1-2 shift special.
So far that test drive was with no intercooling or water injection, and a maximum boost of barely 7 psi actually less considering the datalog did not show boost reach 150 kpa. The smaller turbine housings, water injection, increased boost and tuning should put it about where I would like to have it.
I have to take a moment to bring attention to the fact that the stock compression for this engine is 9.8:1. There have been many debates and arguments about needing to run low compression with turbos here in the past. You should run as high a compression as the boost level you intend to run will allow. In my case once water injection is installed 14 psi with pump gas should not be a problem.
There is also a possibility the oil jets for the pistons are helping also because oil temps are running on what to me is the high side at just over 220 suggesting additional heat being absorbed from the pistons, at some point I'll get more air to the oil cooler.
more timing? is the tgp code conservitive for the more efficent 3900?
i went through high oil temps on my vette. i never got a good fix, but i ran around 275* at the track. intown was around 255. i like cadillac's 3.6, it has a decent sized oil cooler that sits in the valley of the engine and is cooled by coolant.
maybe you will need something more agressive, like a thermostaticly contolled oil cooiling setup, and maybe even a water to oil heat exchanger.
on the copression vs boost...yeah, i dont buy into the common misconception. i have read many turbo books recently and the good information from them says to take advantage of your compression and use proper intercooling to achive high boost on a high compression engine. it said dont fall into the trap that some kit makers suggest, lowering the compression to see more boost and lower egts. what would the point be to run high boost on an engine that doesnt make the most of it. most books go further than what ive said, but thats all i have retained.
and get out and strech those 'long legs'! you are going to need a drag strip to tune that thing at any gear above 2nd!
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87 fiero gt 5spd 3500, 1280 cam and PR, ls6 valve springs, port and polished heads, ported lim, ported uim, 4.3 70mm tb, ported trueleo headers and y pipe, 2.5 inch ex, flowtech muff, gmtuners.com prom, 7730 ecm (GAVE TO BROTHER, divorce reasons.)
96 LT4 6spd corvette. 4:10 gears, Open element intake, pcm4less tune, hurst short shifter, muff elims,
94 geo metro, 1.0l 3cyl gas sipper. scariest car I have ever driven!!! slow, ugly, slow, cheap, slow, handles like a wet noodle.
more timing? is the tgp code conservitive for the more efficent 3900?
i went through high oil temps on my vette. i never got a good fix, but i ran around 275* at the track. intown was around 255. i like cadillac's 3.6, it has a decent sized oil cooler that sits in the valley of the engine and is cooled by coolant.
maybe you will need something more agressive, like a thermostaticly contolled oil cooiling setup, and maybe even a water to oil heat exchanger.
on the copression vs boost...yeah, i dont buy into the common misconception. i have read many turbo books recently and the good information from them says to take advantage of your compression and use proper intercooling to achive high boost on a high compression engine. it said dont fall into the trap that some kit makers suggest, lowering the compression to see more boost and lower egts. what would the point be to run high boost on an engine that doesnt make the most of it. most books go further than what ive said, but thats all i have retained.
and get out and strech those 'long legs'! you are going to need a drag strip to tune that thing at any gear above 2nd!
So far it appears the stock TGP code can be pumped up a little, it was also designed for an automatic and there was an area in the table with considerable timing reduction and I'm sure gear ratios had something to do with that.
I believe the oil temps are kind of high because of the heat it absorbs from the pistons, the cooler is not in the most optimal location and it is getting some heat from one of the mufflers which will get a good bit more heat wrap than the one layer it has to eliminate that. Later I'll invest in some mufflers that will fit in the tail pipe location so I'll have room to add a fan to the cooler. There is an additional cooler that uses coolant at the oil filter so if I can get oil temps down around 175 that will be a big plus.
And second gear would definately need to be on the hwy because it really pulls as the rpm climbs. I'll have the smaller turbine housings on tomorrow to see if that adds to the bottom end and hopefully the water injection kit will be installed also. I'll leave it at its current boost level until the tune is in good shape then I'll turn it up.
The TGP code is conservative for shitty gas in high hot heat climates so that the engine would never blow up probably. Plus the 3900 flows better so you are able to run more before ping under boost anyways.
__________________ New 2010 project (click image)
1994 3100 BERETTA. 200,000+ miles
16.0 1/4 mile when stock. Now ???
Original L82 Longblock with LA1, LX9, LX5 parts
Manifold-back 2.5" SS Mandrel Exhaust. Hardware is SS too.
i thought oil temps below 200 were bad, as in they cant remove the water from the oil. and it keeps the viscocity too high and the detergents arent going to work at low temps.
at least thats what the navy told me. but they also let people who have shit for brains dictate what i do. so who knows if thats legit.
do you have a manifold temp sensor to show what kind of heat is in there? may help pick the turbines for higher engine speeds, by seeing if the turbo is out of its range and blowing hot air instead of making boost....
__________________
87 fiero gt 5spd 3500, 1280 cam and PR, ls6 valve springs, port and polished heads, ported lim, ported uim, 4.3 70mm tb, ported trueleo headers and y pipe, 2.5 inch ex, flowtech muff, gmtuners.com prom, 7730 ecm (GAVE TO BROTHER, divorce reasons.)
96 LT4 6spd corvette. 4:10 gears, Open element intake, pcm4less tune, hurst short shifter, muff elims,
94 geo metro, 1.0l 3cyl gas sipper. scariest car I have ever driven!!! slow, ugly, slow, cheap, slow, handles like a wet noodle.
i thought oil temps below 200 were bad, as in they cant remove the water from the oil. and it keeps the viscocity too high and the detergents arent going to work at low temps.
at least thats what the navy told me. but they also let people who have shit for brains dictate what i do. so who knows if thats legit.
do you have a manifold temp sensor to show what kind of heat is in there? may help pick the turbines for higher engine speeds, by seeing if the turbo is out of its range and blowing hot air instead of making boost....
I understood 180 to be the low limit and considering the oil jets function I would want to be on the low side for the greatest amount of heat removal from the pistons. Clearing out condensation if any develops should be taken care of once the PCV vent is connected ahead of the turbo to suck a fresh charge of air into the crankcase and clear out bad air.
The MAT sensor reading is what two other members in a thread under computer related are helping me with, I have registered a high of 104 units, not sure if that needs to be converted or if it's degrees or celsius, most certainly celsius if the value is a correct output reading. I ran compressor maps and I should be in the 74% efficiency range around 11psi boost, but since I'm only mustering 6psi the map shows 65% which is still okay and definately a non issue when the water injection is added.
I plan to move up to TO4E 57 trim compressors later on, it will only provide 78% peak efficiency which is only four % more than what I currently am capable of so I may not bother.
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