Which MAP sensor and why? 383 LT4
Thread Starter
Staging Lane
Joined: Jan 2011
Posts: 96
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Which MAP sensor and why? 383 LT4 I need help choosing an appropriate replacement MAP sensor. I will try to supply background info that might have some importance in choosing the right MAP sensor. If you need any other information please feel free to ask and I will get that to you as soon as possible.
Thread Starter
Staging Lane
Joined: Jan 2011
Posts: 96
Likes: 0
I am still working on my 93 Camaro Z28 350 LT1 - 383 LT4 conversion for any of you that remember me from about a year ago. I had to pull the engine back out as it would never run right. Took the short block to a new respected machine shop near my area to have it gone through to look for issues when my compressions were off from cylinder to cylinder and during rotating assembly removal I found mixed sets of rod bearings. The Eagle Specialties 383 rotating assembly came with clevite 77 rod bearings and my block was supposedly blueprinted, clearanced and internally balanced by the machine shop. When I pulled it apart I found five of the rod bearing halves were clevite 77 4.06 CB663P STD and the remaining eleven were King Engine bearing: five, JJ 001 C807 SI / five, King Engine GK3 STD C807 SI and one King Engine GK STD C807 SI. I don't mean one rod would have a matching pair of the clevite 77, while the next rod had a matched pair of the King Engine STD or matched pair of King Engine 001. They had one half of a bearing pair in the rod and a bearing half of a different type in the rod cap. Now it has been years since I was in school for auto mechanics but that was always one of those "YOU NEVER DO THIS" things.
We also found they had decked the heads radically and shaved off so much my compression ratio was higher than 12.5-1 even though the shop had ordered a cam rated to handle 10.0 - 11.5 compression ratio and paired it with a cast steel crank and cast aluminum Keith Black pistons (the Keith Black cast aluminum pistons would not hold up to that high of a ratio for long from what I was told). The combustion chambers had to be carved out and polished as much as possible to get the compression ration close to what it should be and special made extra thick Cometic head gaskets ordered to get us the rest of the way there.
I have had several broken valve springs from coil bind even though the shop ordered the above mentioned cam creating a max lift of .595 (nearly .6" of lift) and the new springs which were only rated to handle less than .5" lift. All springs, locks, retainers, roller rocker arms, pushrods and lifters all rated to work together with my cams lift and valve train geometry have been purchased, assembled and clearances checked.
They ordered a larger 58mm bore throttle body and gasket yet never enlarged the openings in the front of the intake to accommodate the increased flow..... and many, MANY other issues like that ranging from the minor to more serious.
I was told a new performance MAP sensor was bought and put on the engine but when I started tearing that down I found the small plastic nipple with the rubber "O" gasket that goes down into the mounting hole and seals the MAP to the intake had been broken off and the end of the nipple and rubber "O" gasket were gone. (not still in the hole) Not to mention it was just my old stock MAP sensor cleaned up. I have upgraded my 93 LT1 single wire O2's to dual heated four wire O2's as well as added a wide band O2 to patch into the laptop for tuning. Upgraded my stock exhaust manifolds to BBK shorty headers with O2 bungs in each collector and I welded in my own bung for the Wide Band O2 approximately 9'o clock position (slightly lower) between end of "y" pipe and before the catalytic.
I have been trying to find what would be the appropriate match for my car and engine set up: 1 bar, 2 bar or 3 bar and what brand makes a good reliable performance one. I truely do not know if I just need a good quality stock style 1 bar sensor or a more complicated one to match my engine build and for programming.
If there are aspects of the engine build that would be influenced by or would influence the MAP sensor and I do not have it listed so far please let me know and I will gladly get any and all information needed to make an educated choice.
Thank you so much for your time and help in this matter. I have spent hours off and on over the past 6 months searching the forums and web for information and just haven't gotten enough that I can sort out and understand to help me out.
Sincerely,
Cpl. Jerry W. Gibson II
Medically Retired USArmy
and long time member of these forums (like 2 years or so)
We also found they had decked the heads radically and shaved off so much my compression ratio was higher than 12.5-1 even though the shop had ordered a cam rated to handle 10.0 - 11.5 compression ratio and paired it with a cast steel crank and cast aluminum Keith Black pistons (the Keith Black cast aluminum pistons would not hold up to that high of a ratio for long from what I was told). The combustion chambers had to be carved out and polished as much as possible to get the compression ration close to what it should be and special made extra thick Cometic head gaskets ordered to get us the rest of the way there.
I have had several broken valve springs from coil bind even though the shop ordered the above mentioned cam creating a max lift of .595 (nearly .6" of lift) and the new springs which were only rated to handle less than .5" lift. All springs, locks, retainers, roller rocker arms, pushrods and lifters all rated to work together with my cams lift and valve train geometry have been purchased, assembled and clearances checked.
They ordered a larger 58mm bore throttle body and gasket yet never enlarged the openings in the front of the intake to accommodate the increased flow..... and many, MANY other issues like that ranging from the minor to more serious.
I was told a new performance MAP sensor was bought and put on the engine but when I started tearing that down I found the small plastic nipple with the rubber "O" gasket that goes down into the mounting hole and seals the MAP to the intake had been broken off and the end of the nipple and rubber "O" gasket were gone. (not still in the hole) Not to mention it was just my old stock MAP sensor cleaned up. I have upgraded my 93 LT1 single wire O2's to dual heated four wire O2's as well as added a wide band O2 to patch into the laptop for tuning. Upgraded my stock exhaust manifolds to BBK shorty headers with O2 bungs in each collector and I welded in my own bung for the Wide Band O2 approximately 9'o clock position (slightly lower) between end of "y" pipe and before the catalytic.
I have been trying to find what would be the appropriate match for my car and engine set up: 1 bar, 2 bar or 3 bar and what brand makes a good reliable performance one. I truely do not know if I just need a good quality stock style 1 bar sensor or a more complicated one to match my engine build and for programming.
If there are aspects of the engine build that would be influenced by or would influence the MAP sensor and I do not have it listed so far please let me know and I will gladly get any and all information needed to make an educated choice.
Thank you so much for your time and help in this matter. I have spent hours off and on over the past 6 months searching the forums and web for information and just haven't gotten enough that I can sort out and understand to help me out.
Sincerely,
Cpl. Jerry W. Gibson II
Medically Retired USArmy
and long time member of these forums (like 2 years or so)
I am still working on my 93 Camaro Z28 350 LT1 - 383 LT4 conversion for any of you that remember me from about a year ago. I had to pull the engine back out as it would never run right. Took the short block to a new respected machine shop near my area to have it gone through to look for issues when my compressions were off from cylinder to cylinder and during rotating assembly removal I found mixed sets of rod bearings. The Eagle Specialties 383 rotating assembly came with clevite 77 rod bearings and my block was supposedly blueprinted, clearanced and internally balanced by the machine shop. When I pulled it apart I found five of the rod bearing halves were clevite 77 4.06 CB663P STD and the remaining eleven were King Engine bearing: five, JJ 001 C807 SI / five, King Engine GK3 STD C807 SI and one King Engine GK STD C807 SI. I don't mean one rod would have a matching pair of the clevite 77, while the next rod had a matched pair of the King Engine STD or matched pair of King Engine 001. They had one half of a bearing pair in the rod and a bearing half of a different type in the rod cap. Now it has been years since I was in school for auto mechanics but that was always one of those "YOU NEVER DO THIS" things.
We also found they had decked the heads radically and shaved off so much my compression ratio was higher than 12.5-1 even though the shop had ordered a cam rated to handle 10.0 - 11.5 compression ratio and paired it with a cast steel crank and cast aluminum Keith Black pistons (the Keith Black cast aluminum pistons would not hold up to that high of a ratio for long from what I was told). The combustion chambers had to be carved out and polished as much as possible to get the compression ration close to what it should be and special made extra thick Cometic head gaskets ordered to get us the rest of the way there.
I have had several broken valve springs from coil bind even though the shop ordered the above mentioned cam creating a max lift of .595 (nearly .6" of lift) and the new springs which were only rated to handle less than .5" lift. All springs, locks, retainers, roller rocker arms, pushrods and lifters all rated to work together with my cams lift and valve train geometry have been purchased, assembled and clearances checked.
I have been trying to find what would be the appropriate match for my car and engine set up: 1 bar, 2 bar or 3 bar and what brand makes a good reliable performance one. I truely do not know if I just need a good quality stock style 1 bar sensor or a more complicated one to match my engine build and for programming.
