Weak LT1 ???
Thread Starter
Pro
Joined: Apr 2002
Posts: 708
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From: Alexandria VA
Weak LT1 ???
Went to MIR today to get a baseline on the vette before doing any mods. The weather here was VERY hot and that may account for my performance but I thought a 95 LT1 Auto 3.07 geared vette would be faster... :cry
Anyway, the timeslip is below and I ran in full street trim with a weight of 3265 without me in it (235) and race weight of an even 3500 with a half tank of gas. :D
.528 :cheers:
2.157
6.255
9.582
74.01
12.494
14.969 :mad
91.55 :confused:
I was only able to make one run as it wasnt really a test session today. At any rate, I did have fun and enjoyed myself!! I guess its time to order more parts than I had anticipated...
Mike
[Modified by Bravery, 6:17 PM 8/17/2002]
Anyway, the timeslip is below and I ran in full street trim with a weight of 3265 without me in it (235) and race weight of an even 3500 with a half tank of gas. :D
.528 :cheers:
2.157
6.255
9.582
74.01
12.494
14.969 :mad
91.55 :confused:
I was only able to make one run as it wasnt really a test session today. At any rate, I did have fun and enjoyed myself!! I guess its time to order more parts than I had anticipated...
Mike
[Modified by Bravery, 6:17 PM 8/17/2002]
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: Weak LT1 ??? (Bravery)
I WOULD chalk it up to the driver, but some things tell me otherwise.
First and foremost, it's an AUTO. There isn't much you can do to screw up once you leave the line. You had a very good reaction time. Not a very good 60' for an auto, it's more like the 60's I get with my 6-spd.
Something else that concerns me is the MPH. I don't care how bad you screw up you should have a good MPH. Usually more wheelspin means a little higher MPH. A stock LT1 should run around 99-102 mph. A friend of mine was a ragged out Z-28 that ran 13.9 @ 99 mph. It has well over 100k miles on the clock.
I also don't think the weather can knock off 10 mph. I can't begin to say what is wrong, but certainly somoething. I would run a compression test and a leakdown test. The LT1 valvesprings are supposed to be pretty weak. I hear they are shot if you hit the rev limiter just a few times. Maybe your springs are REAL weak.
I don't know man, something ain't quite right. Perhaps a little history on the car?
First and foremost, it's an AUTO. There isn't much you can do to screw up once you leave the line. You had a very good reaction time. Not a very good 60' for an auto, it's more like the 60's I get with my 6-spd.
Something else that concerns me is the MPH. I don't care how bad you screw up you should have a good MPH. Usually more wheelspin means a little higher MPH. A stock LT1 should run around 99-102 mph. A friend of mine was a ragged out Z-28 that ran 13.9 @ 99 mph. It has well over 100k miles on the clock.
I also don't think the weather can knock off 10 mph. I can't begin to say what is wrong, but certainly somoething. I would run a compression test and a leakdown test. The LT1 valvesprings are supposed to be pretty weak. I hear they are shot if you hit the rev limiter just a few times. Maybe your springs are REAL weak.
I don't know man, something ain't quite right. Perhaps a little history on the car?
Le Mans Master
Joined: Sep 2000
Posts: 6,473
Likes: 1
From: Cleveland
Cruise-In III Veteran
Cruise-In IV Veteran
Re: Weak LT1 ??? (Nathan Plemons)
This is my timeslip in hot weather at Beach Bend track, I got a 14 flat at 100.67 with only elims. Somethin might be up with your car? :crazy:
Burning Brakes
Joined: Dec 2000
Posts: 849
Likes: 0
From: Lafayette LA
Re: Weak LT1 ??? (Bravery)
Like nathan said, the hp is way down. Ya need to scan it. I would bet that a lot of timing is being pulled due to heat and other issues, but I would be suprised if that alone cost you 8-9 mph. Have you checked to see if the cat or fuel filter is clogged?
Melting Slicks
Joined: Mar 1999
Posts: 2,535
Likes: 2
From: Rochester NY
Re: Weak LT1 ??? (olephart)
First time out? You will never have good ET. When my first time out, I managed to run 14.6 and down to 13.8 when my LT1 6 speed were stock. Any LT1 should in the low 14s and high 13s second car.
Bruce
93LT1 Conv w/ZF6
BlownD1-SC/N2O
ARE built 383ci/Stage II heads
Bruce
93LT1 Conv w/ZF6
BlownD1-SC/N2O
ARE built 383ci/Stage II heads
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Pro
Joined: Apr 2002
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From: Alexandria VA
Re: Weak LT1 ??? (Hardcorvette)
No, I did not lift. I am not the type to "sandbag" a run.
I do have drag racing experience with Camaro's, but this is my first ever pass in THIS car. I just thought an LT1 vette would be faster.
I will check the basics tomorrow (plugs, wires, fluids), maybe its something simple causing a severe performance drop.
Weather information for my run:
Temperature - 89.06° F / 31.7° C
Dew Point - 71.96° F / 22.2° C
Humidity - 57%
Pressure - 30.04 in / 1017.0 hPa
Maryland International Raceway is a sea-level track.
Mike
[Modified by Bravery, 11:51 AM 8/18/2002]
I do have drag racing experience with Camaro's, but this is my first ever pass in THIS car. I just thought an LT1 vette would be faster.
I will check the basics tomorrow (plugs, wires, fluids), maybe its something simple causing a severe performance drop.
Weather information for my run:
Temperature - 89.06° F / 31.7° C
Dew Point - 71.96° F / 22.2° C
Humidity - 57%
Pressure - 30.04 in / 1017.0 hPa
Maryland International Raceway is a sea-level track.
Mike
[Modified by Bravery, 11:51 AM 8/18/2002]
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Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: Weak LT1 ??? (Bravery)
Beech Bend is consistently 100% humidity. I wish I could see what my car would do in good weather :)
Start tracking it down, you may find something stupid like a burnt plug wire. What type of fuel economy do you get? If it's way down you may want to start looking at ignition system and emissions.
I know we have very recently had to replace the cat on our blazer. It's defective fuel injection system dumps too much fuel and eventually clogs the cat. When we first bought it fuel economy just sucked. It drove fine, or so we thought. After a while though it got worse and started acting up. It got to the point that it wouldn't rev or anything. We tracked it to a clogged cat and had the dealer replace it under warranty. WOW. The thing gets much better mileage and isn't nearly as under powered as I thought it was.
Start tracking it down, you may find something stupid like a burnt plug wire. What type of fuel economy do you get? If it's way down you may want to start looking at ignition system and emissions.
I know we have very recently had to replace the cat on our blazer. It's defective fuel injection system dumps too much fuel and eventually clogs the cat. When we first bought it fuel economy just sucked. It drove fine, or so we thought. After a while though it got worse and started acting up. It got to the point that it wouldn't rev or anything. We tracked it to a clogged cat and had the dealer replace it under warranty. WOW. The thing gets much better mileage and isn't nearly as under powered as I thought it was.
Thread Starter
Pro
Joined: Apr 2002
Posts: 708
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From: Alexandria VA
Re: Weak LT1 ??? (Raistlin)
Nathan - the car gets around 19mpg in the city and (depending on how I drive) about 25 on the highway.
Raistlin - Traction control was turned off.
So far this morning, I have determined that my trans fluid smells like burnt rubber, I also changed the oil (came out like maple syrup), doing the plugs now, will post results shortly.
I am now thinking that my trans may have been slipping a good portion of the quarter, but that is just an assumption. It gets flushed out tomorrow, along with a new filter. I am confident that the previous owner did no preventive maintenance on the car. :(
Mike
Raistlin - Traction control was turned off.
So far this morning, I have determined that my trans fluid smells like burnt rubber, I also changed the oil (came out like maple syrup), doing the plugs now, will post results shortly.
I am now thinking that my trans may have been slipping a good portion of the quarter, but that is just an assumption. It gets flushed out tomorrow, along with a new filter. I am confident that the previous owner did no preventive maintenance on the car. :(
Mike
Le Mans Master
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From: Louisville,KY
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Cruise-In II Veteran
Re: Weak LT1 ??? (Bravery)
Something is wrong :yesnod: .....My Vette(95auto3.07) when stock ran 13.5 @ 105 at Beech Bend(Bowling Green). And its not the Best track in the world either.
Check to make sure it is getting full throttle. Get someone to mash the gas pedal to the floor.....while you check and make sure the linkage on the TB is wide open. If its not... there is an adjustment on the cable.
:cheers:
Check to make sure it is getting full throttle. Get someone to mash the gas pedal to the floor.....while you check and make sure the linkage on the TB is wide open. If its not... there is an adjustment on the cable.
:cheers:
Thread Starter
Pro
Joined: Apr 2002
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From: Alexandria VA
Re: Weak LT1 ??? (Zora)
** UPDATE **
Just got in from pulling all the plugs (not hard to do at all) and the results are below... I have cleaned and regapped them to .045 and will see what happens. I also put anti-seize on the bolts as I learned from my LS1 how much of a bear it can be without anti-seize and aluminum heads...
1-.060
2-.061
3-.060
4-.062
5-.065
6-.064
7-.062
8-.066
The plugs have AC 905 on them, not sure if thats original or not but judging by the rust on the head of the plug, I would venture to say so.
Mike
[Modified by Bravery, 1:07 PM 8/18/2002]
Just got in from pulling all the plugs (not hard to do at all) and the results are below... I have cleaned and regapped them to .045 and will see what happens. I also put anti-seize on the bolts as I learned from my LS1 how much of a bear it can be without anti-seize and aluminum heads...
1-.060
2-.061
3-.060
4-.062
5-.065
6-.064
7-.062
8-.066
The plugs have AC 905 on them, not sure if thats original or not but judging by the rust on the head of the plug, I would venture to say so.
Mike
[Modified by Bravery, 1:07 PM 8/18/2002]
Burning Brakes
Joined: Dec 2000
Posts: 849
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From: Lafayette LA
Re: Weak LT1 ??? (Bravery)
Sounds like a good start. AC plugs are supposed to work ok in the LT1, but lots of people use the NGK TR55 - nice copper electrode and only $2 at most auto stores.
If your plugs were that bad, and based on your mileage figures, I might change the front O2 sensors too. Use GM, they work better than the other brands.
The fuel filter usually loads up around 20,000 and can reduce power.
If it's been running fat, it's common for a lot of carbon to build up on the valves and pistons and around the throttle body. Could be adding to detonation based spark retard. Sea Foam or GM TEC (top engine cleaner) works great for this problem. Probably should do it before you change O2 sensors and plugs.
I hope you get it running as good as it looks - nice car.
If your plugs were that bad, and based on your mileage figures, I might change the front O2 sensors too. Use GM, they work better than the other brands.
The fuel filter usually loads up around 20,000 and can reduce power.
If it's been running fat, it's common for a lot of carbon to build up on the valves and pistons and around the throttle body. Could be adding to detonation based spark retard. Sea Foam or GM TEC (top engine cleaner) works great for this problem. Probably should do it before you change O2 sensors and plugs.
I hope you get it running as good as it looks - nice car.
Melting Slicks
Joined: Mar 2002
Posts: 2,203
Likes: 63
From: Staten Island NY
Re: Weak LT1 ??? (Bravery)
Cant hurt to replace the plugs and do a TB bypass, you dont need to buy the kit, just connect the hose on the drivers side of the TB to the inlet on the passengers side, made a differance on my 95 Auto.
The temp is also a big deal - both outside air and coolent, how hot was the engine coolent while staging?
My 95 Auto runs a consistant 13.5
The temp is also a big deal - both outside air and coolent, how hot was the engine coolent while staging?
My 95 Auto runs a consistant 13.5
Melting Slicks
Joined: Mar 2002
Posts: 2,203
Likes: 63
From: Staten Island NY
Re: Weak LT1 ??? (Bravery)
thats to hot, for 20 bucks go with a 160 therm and instal an overide switch to turn on the fans. the coolent temp should be around 170 on the starting line, hot engine coolent also have a negative effect on the transmission- if the engine coolent is high so will the tranny fluid.
Instructor
Joined: Feb 2001
Posts: 171
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From: Raleigh North Carolina
Re: Weak LT1 ??? (Bravery)
The coolant temp was hot, like everything else, and it showed 225 I believe...
Mike
Mike
