Loose compretion?
03-28-2007, 04:59 PM
#1
Launching!
Thread Starter
iTrader: (1)
Join Date: May 2006
Location: Greensburg, IN
Posts: 268
Likes: 0
Received 0 Likes
on
0 Posts
Loose compretion? I have been takin to a guy here at work. My car has 107k on the clock and my motor is 10:1, he seems to think the more miles i put on my car, the compretion with go down. He said that I probley only have about a 9-9.5:1 now with that many miles on it. Is this true? And secondly when i went to the track when i first got my car i ran 14.1 without my lid. And also i know im dumb 
but i was running 87 oct. He does not think im going to do better than a 13.8 at the track cuz he doesnt see my car dropping that much time(hope n to go like 13.5) with a lid and 92 in it now. I believe it will but iono what you guys think thxs...
but i was running 87 oct. He does not think im going to do better than a 13.8 at the track cuz he doesnt see my car dropping that much time(hope n to go like 13.5) with a lid and 92 in it now. I believe it will but iono what you guys think thxs... 
03-28-2007, 06:11 PM
#2
TECH Fanatic
Originally Posted by t/a for life
I have been takin to a guy here at work. My car has 107k on the clock and my motor is 10:1, he seems to think the more miles i put on my car, the compretion with go down. He said that I probley only have about a 9-9.5:1 now with that many miles on it. Is this true? And secondly when i went to the track when i first got my car i ran 14.1 without my lid. And also i know im dumb but i was running 87 oct. He does not think im going to do better than a 13.8 at the track cuz he doesnt see my car dropping that much time(hope n to go like 13.5) with a lid and 92 in it now. I believe it will but iono what you guys think thxs...
but i was running 87 oct. He does not think im going to do better than a 13.8 at the track cuz he doesnt see my car dropping that much time(hope n to go like 13.5) with a lid and 92 in it now. I believe it will but iono what you guys think thxs...hahahah sorry i had to do it
but on topic I have seen stock LS1 with mor miles than you do low 13's easy, you probably have to launch better
03-28-2007, 06:15 PM
#3
Launching!
Thread Starter
iTrader: (1)
Join Date: May 2006
Location: Greensburg, IN
Posts: 268
Likes: 0
Received 0 Likes
on
0 Posts
Its not a random joe at work. He knows what hes talkin about thats why i dont just blow him off, he just doesnt know alot about the newer cars. He owns a 68' bird, completly restored. heads, cam, headers, intake, exhaust..and some other goodies. Runs 12.9, so he knows alittle about what hes talkin about. Just needed info from you guys that have more knowlege on these type of cars thxs...
03-28-2007, 06:45 PM
#4
TECH Fanatic
Originally Posted by t/a for life
Its not a random joe at work. He knows what hes talkin about thats why i dont just blow him off, he just doesnt know alot about the newer cars. He owns a 68' bird, completly restored. heads, cam, headers, intake, exhaust..and some other goodies. Runs 12.9, so he knows alittle about what hes talkin about. Just needed info from you guys that have more knowlege on these type of cars thxs...
03-28-2007, 06:59 PM
#5
Launching!
Thread Starter
iTrader: (1)
Join Date: May 2006
Location: Greensburg, IN
Posts: 268
Likes: 0
Received 0 Likes
on
0 Posts
jesus! haha. The track im going to kinda sucks so iono...but he says im not coming close to his 12.9 and i know my damn car can. Haha just frustrating when you know it can, and people dogg your ride pisses me off so bad!!
Trending Topics
03-28-2007, 07:32 PM
#8
I'm just a newb too, and I certainly don't know more than 95% of the people on here, but I think your friend is off on the wrong track. When cars get old the cylinders can lose compression (has to do with the ring's seal against the wall I think), but that's not the same type of compression as the Compression Ratio (10:1 and all that). Compression Ratio has to do with a number of other factors (pistons, heads, etc.), none of them age or wear and tear.
That's why you hear people with high-mile engines sometimes say, "My engine still makes good compression," or "You better check the compression on that cylinder," or whatever. Has nothing to do with the Compression Ratio.
Not sure on any of that, though.
That's why you hear people with high-mile engines sometimes say, "My engine still makes good compression," or "You better check the compression on that cylinder," or whatever. Has nothing to do with the Compression Ratio.
Not sure on any of that, though.
03-28-2007, 07:46 PM
#9
TECH Veteran
iTrader: (18)
Join Date: Sep 2005
Location: SW Houston
Posts: 4,185
Likes: 0
Received 0 Likes
on
0 Posts
138K miles andiprob have around 10.75:1-11:1 Compression with my 5.3L heads and my cylinder's had nice healthy cross hatches.
Dont listen to everything ppl say.
take it with a grain of salt.
Dont listen to everything ppl say.
take it with a grain of salt.
03-28-2007, 07:55 PM
#10
Launching!
Join Date: Jul 2004
Location: Arizona.
Posts: 204
Likes: 0
Received 0 Likes
on
0 Posts
^Actually your pretty much on the nose. It does effectively lower your CR a bit, but its hard to say just how much and frankly you cant tell just doing a compression test.
Your car probably does have a bit less compression than when it was new. But let me give you an example from the other side of the coin. My roomate and I run DSMs (turbo 4 bangers). He has about 90 psi on all cylinders. Thats stupid low. The car has 140K plus miles of about 18psi (or more) boost. So it's to be expected.
He ran a 13.3 at 107 last time at a track where new 300HP Mustangs cant get out of the 14s.
So loosing a little compression will not hurt you too much. What will is track conditions. Some tracks are faster than others. I grew up about 3 miles from Bamndimere raceway in CO. Its at like 5800 Ft above sea level. A NA 13.0 car at sea level runs about a 14.0 there. No joke. The lower air density at that altatude makes it hard for any engine to get the same amount of air and therefore power. Some tracks are slow because the air is just so damn hot its density goes to ****. I now live in Phoenix. Its unreal how slow your can feel at lunch-time compared to 10:00 PM. really pisses me off actually. And if the track prep sucks at your track, you will not get a good 60 foot time and that will kill an ET faster than anything else.
What was your 60 foot when you ran the 14.XX?
Here is what I recomend: Change your plugs. Make sure the new ones are gaped to factory spec. Put in a half tank of 91 or 93 or whatever premium gas. Make sure your air filter is clean. Check your base timing (ask the guy at work, he will know how. You will need to borrow a timing light.). Make sure all the clamps on your intake plumbing are tight. Set your tire pressures to whatever is recomended for your tires. Get any pea gravel and crap off them before you even drive to the track.
When you get to the track, let the car cool a bit, then get into the staging lanes. And then work on your launch. Dont dump the clutch or floor it right out of the hole. Try to be smooth and fast. If its an A4, turn off the damn traction controll. Thats useless to you.
Interesting thing a lot of guys dont know: You time at the track does not start when the green light goes. It starts when you cross the staging beams. So take your time. Dead serious. My first time racing. I launched when I was ready, not when the light went green. I did not give a flying **** if people sniggered.
If you can get that 60 time down to 2.0 or less, you will hit your 13s IMHO.
Your car probably does have a bit less compression than when it was new. But let me give you an example from the other side of the coin. My roomate and I run DSMs (turbo 4 bangers). He has about 90 psi on all cylinders. Thats stupid low. The car has 140K plus miles of about 18psi (or more) boost. So it's to be expected.
He ran a 13.3 at 107 last time at a track where new 300HP Mustangs cant get out of the 14s.
So loosing a little compression will not hurt you too much. What will is track conditions. Some tracks are faster than others. I grew up about 3 miles from Bamndimere raceway in CO. Its at like 5800 Ft above sea level. A NA 13.0 car at sea level runs about a 14.0 there. No joke. The lower air density at that altatude makes it hard for any engine to get the same amount of air and therefore power. Some tracks are slow because the air is just so damn hot its density goes to ****. I now live in Phoenix. Its unreal how slow your can feel at lunch-time compared to 10:00 PM. really pisses me off actually. And if the track prep sucks at your track, you will not get a good 60 foot time and that will kill an ET faster than anything else.
What was your 60 foot when you ran the 14.XX?
Here is what I recomend: Change your plugs. Make sure the new ones are gaped to factory spec. Put in a half tank of 91 or 93 or whatever premium gas. Make sure your air filter is clean. Check your base timing (ask the guy at work, he will know how. You will need to borrow a timing light.). Make sure all the clamps on your intake plumbing are tight. Set your tire pressures to whatever is recomended for your tires. Get any pea gravel and crap off them before you even drive to the track.
When you get to the track, let the car cool a bit, then get into the staging lanes. And then work on your launch. Dont dump the clutch or floor it right out of the hole. Try to be smooth and fast. If its an A4, turn off the damn traction controll. Thats useless to you.
Interesting thing a lot of guys dont know: You time at the track does not start when the green light goes. It starts when you cross the staging beams. So take your time. Dead serious. My first time racing. I launched when I was ready, not when the light went green. I did not give a flying **** if people sniggered.
If you can get that 60 time down to 2.0 or less, you will hit your 13s IMHO.
03-28-2007, 08:29 PM
#12
A little bit of knowledge is a dangerous thing. Your friend seems to have mastered some things, but is talking out of his elbow on this one.
If he didn't wask you weather conditions, 60 foot times, reaction time and mph at the end of the 1/4, he is just **** talking.
Nuff said
If he didn't wask you weather conditions, 60 foot times, reaction time and mph at the end of the 1/4, he is just **** talking.
Nuff said
03-28-2007, 09:12 PM
#15
11 Second Club
iTrader: (20)
Join Date: Oct 2006
Location: Virginia
Posts: 3,131
Likes: 0
Received 0 Likes
on
0 Posts
compression not compretion lol .if the cylinders wore enough to lose a half a point of compression the car would run like ****.these engines have very loose clearances to start with.tell your friend at work to stfu.put in some 3.73s drs and all your boltons and blow his doors.hell a converter and the drs may do it
03-28-2007, 09:28 PM
#16
Originally Posted by 5_02ls1
compression not compretion lol .if the cylinders wore enough to lose a half a point of compression the car would run like ****.these engines have very loose clearances to start with.tell your friend at work to stfu.put in some 3.73s drs and all your boltons and blow his doors.hell a converter and the drs may do it
Lol thank you for pointiong out compression it was driving me nuts.
It's also lose. loose would be like if a nut and bolt are loose you need to tighten them.
Originally Posted by Sparetire
Your car probably does have a bit less compression than when it was new. But let me give you an example from the other side of the coin. My roomate and I run DSMs (turbo 4 bangers). He has about 90 psi on all cylinders. Thats stupid low. The car has 140K plus miles of about 18psi (or more) boost. So it's to be expected.
He ran a 13.3 at 107 last time at a track where new 300HP Mustangs cant get out of the 14s.
He ran a 13.3 at 107 last time at a track where new 300HP Mustangs cant get out of the 14s.
03-28-2007, 09:33 PM
#18
TECH Fanatic
A little bit of knowledge is a dangerous thing. Your friend seems to have mastered some things, but is talking out of his elbow on this one.