Compression amounts??

[eXploitedGST]

alright i did a compression test on my car about a week ago and my results were cylander 1-4 going left to right

1 - 120 psi
2 - 130 psi
3 - 130 psi
4 - 130 psi

im assuming thats good for our lower compression turbo engines. not to mention that my cars engine was freezing cold when i did it. are those results good or what?

 

[candela]

IMO thats not vry good. I think the service limit is like 12x psi or so. Anyhow make sure your car is warm before you do it dude. Add some oil to the cylinders and see what happens also.

Austin

 

[Tevenor]

Was the ambient temperature 'freezing cold' or was the car 'freezing cold' as in it wasn't warmed up to operating temperatures? Huge difference.

 

[hostile]

I did mine while it was cold (50F) and I only hit 130's.

I dont think it is a problem because my car was perfroming fine.

What you need to worry about is the one cylinder that is in the 80's.

 

[candela]

Oh.... I thought you meant your car wasnt warmed up or anything. I still would feel comfortable if my motor had that compression. its not horrible, I just like mine nice and high =)

 

[98gsxdude]

Make sure the your at WOT and don't forget to disconnect your fuel and spark

 

[98gsxdude]

also shouldn't it be at 170kpa

 

[LaserRST]

Your engine should definately be warm when performing a compression test. Do one test dry and one test wet (with oil) to see what kind of changes you find. The service limit is 122kpa and it should be upward to about 164 kpa, according to Haynes. Remove all the spark plug wires to allow the engine to turn over easier. It should take at least three complete revolutions to before its done. Some testers actually pop when it hits its peak (Craftsman).

 

[LaserRST]

Oh yea there also shouldnt be more than 12kpa difference between cylinders. Retest that #1, if you have a rough idle than that could be your cause.

 

[eXploitedGST]

what do u mean check my cylander that was in the 80's????? the lowest was 120... i think that one i only did 3 revs and the other 3 cylander i did 4. so i think there all 130. it wasnt at WOT either. and yes the block was cold.


good news! i almost siezed my engine today! yay hahahah it freaked me out when i seen my oil pressure gauge on 0 psi. the copper line slipped out of the pressure fitting and all my fluid sprayed out. lucky for me i noticed right away.

 

[LaserRST]

Think some ones tryna tell you somethin.... time for a lil rebuild.

 

[alcali247]

i thought that 1gens and 2nd gens had the same compression. my
comression was 198 190 190 160

 

[LaserRST]

Originally posted by alcali247
i thought that 1gens and 2nd gens had the same compression. my
comression was 198 190 190 160

... hmm... I would have that 160 checked out. It shouldnt have a difference of 12 psi per cylinder and thats 30!! You can have more than 164psi. I had 185 on my recondition a while back, but due to the fact that it took too long to get my bottle neck hone I couldnt break the glaze for my new rings.... this quickly wore down to 150 But oh well car still runs great.

 

[Tevenor]

1G's have 7.8:1 pistons and 2G have 8.5:1 pistons.

There is a big difference in the compression tester results. A good 1G is 155 across all 4 with the service limit being 120. A good 2G is 180 across all 4. My 9:1 6-bolt block runs 200 across the board.

 

[alcali247]

Originally posted by Tevenor
1G's have 7.8:1 pistons and 2G have 8.5:1 pistons.

There is a big difference in the compression tester results. A good 1G is 155 across all 4 with the service limit being 120. A good 2G is 180 across all 4. My 9:1 6-bolt block runs 200 across the board.

so why is my cars compression so high on those first three cylinders
and the last one so low. that makes no cents to me

 

[LaserRST]

It can be any thing from a burned piston, broken rings, head gasket, bent valves, worn cylinder, didnt do CR test right... etc. etc... It needs to be looked at at least. IMO

 

[alcali247]

it can be that serious?why is the other cylinders so high. its a stock
motor.

 

[hostile]

I wouldnt worrya bout it too much. You probably did the test wrong. Unless your smoking alo and are blowing the dip stick out...you will be fine.

 

[Tevenor]

Originally posted by alcali247


so why is my cars compression so high on those first three cylinders
and the last one so low. that makes no cents to me

Carbon deposits on the piston could easily account for that.

 

[MaxBoost]

I dont want to make yet another thread but I want a quick answer considering Im about to buy expensive BB turbo setup.
My compression was 150 across. Is this strong enough to dump that kind of cash into it.
Someone with experience give me advice

107k on stock engine that had never had the head off.

 

[turbobrian]

Save your money on that bb turbo, in my opinion they are a pain in the ass for a daily driver. There is so much more to slapping on a turbo. I would start a new thred first off. List your current mods to help others tell you the way. Then you will get some real answers.

brian
new eng dsm

Originally posted by MaxBoost
I dont want to make yet another thread but I want a quick answer considering Im about to buy expensive BB turbo setup.
My compression was 150 across. Is this strong enough to dump that kind of cash into it.
Someone with experience give me advice

107k on stock engine that had never had the head off.

 

[turbobrian]

Wow! This is why i hate message boards, people get on you about everything. For someone that is newer to the dsm word, a bb turbo at a hefty price is in my opinion not a good idea. There are so many other turbos that have gone fast and can be very reliable. I know bb turbos are awsome things, just not for someone learning the ropes. Something as simple as giving it to much oil pressure or not using a proper filter can cause it to go bye bye.

brian
new eng dsm

 

[Tevenor]

Originally posted by turbobrian
Save your money on that bb turbo, in my opinion they are a pain in the ass for a daily driver. There is so much more to slapping on a turbo. I would start a new thred first off. List your current mods to help others tell you the way. Then you will get some real answers.

brian
new eng dsm

Huh? How in the hell is a bb turbo 'a pain in the ass' for a daily driver? Turbo slapping?

 

[Tevenor]

Originally posted by turbobrian
Wow! This is why i hate message boards, people get on you about everything. For someone that is newer to the dsm word, a bb turbo at a hefty price is in my opinion not a good idea. There are so many other turbos that have gone fast and can be very reliable. I know bb turbos are awsome things, just not for someone learning the ropes. Something as simple as giving it to much oil pressure or not using a proper filter can cause it to go bye bye.

brian
new eng dsm

I agree with the bb is not the ideal solution for everyone and every situation, but no turbo is. However that is not what you said. You said it was a PITA for a daily driver, which is completely and utterly false. Don't spout garbage and people won't get on your case.

And I am still confused as to what 'turbo slapping' is?

 

[turbobrian]

Well maybe i should have got more info about how much he drives his car. BB turbo need very very clean oil. If you are driving your car alot, putting miles on it quickly, means you change your oil often. Making it more expensive in the long run. Im not sure what oil he is using but i would think its just reg oil. Switching to synthetic, would one cause some leaks (which does happen most of the time) and is more expensive. If i were using a $1500 bb turbo i would want to run the very best oil. Just to make things clear i still think a bb turbo isnt the best idea for him. With the money he saves he can do so many more great things to his car. A far as my comment about slapping in a turbo, it was just a figure of speach. Maybe i should have said installing a turbo to make things clear.

brian
new eng dsm

Originally posted by Tevenor



I agree with the bb is not the ideal solution for everyone and every situation, but no turbo is. However that is not what you said. You said it was a PITA for a daily driver, which is completely and utterly false. Don't spout garbage and people won't get on your case.

And I am still confused as to what 'turbo slapping' is?