Why is the LT1 so hot in traffic?
Thread Starter
Racer
Joined: Jun 2002
Posts: 428
Likes: 0
From: Dallas Tx
Why is the LT1 so hot in traffic?
After sitting in traffic today with the outside temp pushing 100, and the reading off the pavement closer to 110, I started thinking about why the LT1 doesn't like traffic. My temps got to 230 water and 250 oil in traffic. This with a good clean radiator, good fans, etc.
When I got back on the freeway, the temps dropped to the usual 180 water, but the oil temp dropped slowly. In the same heat if I avoid traffic, the water stays below 180 and the oil about 200.
The Cats sit astride the engine, very near the oil filter and pan. My theory is that the LT1 cats are cooking the oil, which in turn drives up the water temps in traffic. On a ZR 1 or L98, or (most other cars for that matter) the cats are downstream and cook only the transmission.
I've wondered if a LT1 with long headers and dual cats after the headers would intrinsically run cooler in traffic. I've also wondered if hood louvers would allow better radiator air flow in traffic.
Anyone have any first hand experience with LT1 long headers and traffic temps. Just curious.
When I got back on the freeway, the temps dropped to the usual 180 water, but the oil temp dropped slowly. In the same heat if I avoid traffic, the water stays below 180 and the oil about 200.
The Cats sit astride the engine, very near the oil filter and pan. My theory is that the LT1 cats are cooking the oil, which in turn drives up the water temps in traffic. On a ZR 1 or L98, or (most other cars for that matter) the cats are downstream and cook only the transmission.
I've wondered if a LT1 with long headers and dual cats after the headers would intrinsically run cooler in traffic. I've also wondered if hood louvers would allow better radiator air flow in traffic.
Anyone have any first hand experience with LT1 long headers and traffic temps. Just curious.
Team Owner
Joined: Sep 2001
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From: Athens AL
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Re: Why is the LT1 so hot in traffic? (tkrussell)
L98s will heat up just as fast as the LT1.
I dont think the precats are really cooking the oil, people with headers report almost the same temps.
The fiberglass hood is like a hot box, it absorbs and traps all the heat from the engine and it cant get out. People with Greenwood Heat extractors may have lower temps because of the vent openings though.
My theory is that the fan settings are too high, the water pump does not flow enough, and the radiator is too small for the engine.
I dont think the precats are really cooking the oil, people with headers report almost the same temps.
The fiberglass hood is like a hot box, it absorbs and traps all the heat from the engine and it cant get out. People with Greenwood Heat extractors may have lower temps because of the vent openings though.
My theory is that the fan settings are too high, the water pump does not flow enough, and the radiator is too small for the engine.
Race Director
Joined: Aug 2002
Posts: 13,356
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From: tucson AZ
St. Jude Donor '04 & '05
Re: Why is the LT1 so hot in traffic? (tkrussell)
Whatever year vette......they all run "HOT"......facts of vette life....even when you do everything to catch the problem......been there done that...
tony
:smash: :smash: :smash:
tony
:smash: :smash: :smash:
Burning Brakes
Joined: Aug 2001
Posts: 1,238
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From: walled lake MI
Re: Why is the LT1 so hot in traffic? (tkrussell)
After sitting in traffic today with the outside temp pushing 100, and the reading off the pavement closer to 110, I started thinking about why the LT1 doesn't like traffic. My temps got to 230 water and 250 oil in traffic. This with a good clean radiator, good fans, etc.
When I got back on the freeway, the temps dropped to the usual 180 water, but the oil temp dropped slowly. In the same heat if I avoid traffic, the water stays below 180 and the oil about 200...
When I got back on the freeway, the temps dropped to the usual 180 water, but the oil temp dropped slowly. In the same heat if I avoid traffic, the water stays below 180 and the oil about 200...
[Modified by tempest, 11:17 PM 7/17/2003]
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Team Owner
Joined: Mar 2001
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From: Cincinnati, Oh USA
Re: Why is the LT1 so hot in traffic? (tkrussell)
I got my a/c changed over to R134a today and it was 87 and slow rush hour traffic going home. I had the air on to see where the engine temperature would go. It rose to 203 on a long stoplight wait but dropped to 197 when I finally could get up to 35 mph. I have a 195 stat but I also have a Stewart water pump. If there is an aftermarket higher flow waterpump for LT-1's, I think that would help, it sure made a difference for my L98.
Burning Brakes
Joined: Jun 2000
Posts: 913
Likes: 17
From: Chatsworth, Ga.
Re: Why is the LT1 so hot in traffic? (tkrussell)
I put a Griffen and a 160 degree thermo in mine and now on hot days, 100 the vette runs at about 186 on freeway and around 193 in stop and go traffic. A large radiator works wonders on the LT-1.
:flag
[Modified by Danah92LT-1, 11:20 PM 7/17/2003]
:flag
[Modified by Danah92LT-1, 11:20 PM 7/17/2003]
Advanced
Joined: May 2003
Posts: 60
Likes: 0
Re: Why is the LT1 so hot in traffic? (tkrussell)
I know you said your radiator is clean, however if you haven't looked between the radiator and condensor recently you might want to check it out. My '90 L98 had a plastic grocery sack stuck there, causing the exact same problem you're describing.
Le Mans Master
Joined: Oct 2000
Posts: 6,362
Likes: 30
From: Oak Harbor WA
Re: Why is the LT1 so hot in traffic? (FullShred)
Mine will eventually climb to the temp for the 2nd fan to come on. Used to be 228, now it is 215. Car stays at about 197-200 when using the freeway with lite traffic.
These cars are designed to run hot for better emissions. Mobil1 is required for a reason.
These cars are designed to run hot for better emissions. Mobil1 is required for a reason.
Melting Slicks
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
Re: Why is the LT1 so hot in traffic? (tkrussell)
Because the fans aren't programmed to come on until 226 degrees. No air flow through the rad and it's not going to cool your engine. My guess is they did they to help pass emissions tests.
:cheers:
:cheers:
Drifting
Joined: Mar 1999
Posts: 1,250
Likes: 1
From: Greensboro NC
Re: Why is the LT1 so hot in traffic? (tkrussell)
Your numbers look normal for a stock thermostat car, however the 180F at driving look to me like you have a 160F thermo in there since a stock thermo even on the interstate will keep the coolant at 210F when hot outside.......your numbers don't look out of range at all for me. Once oil gets hot it only very slowly will cool down even if the coolant has gone down again. Engine builders say that the optimum oil temperature is 210F and engine temp 200.........this is the most efficient temps, providing you can keep the incoming air charge as cool as possible......
After sitting in traffic today with the outside temp pushing 100, and the reading off the pavement closer to 110, I started thinking about why the LT1 doesn't like traffic. My temps got to 230 water and 250 oil in traffic. This with a good clean radiator, good fans, etc.
When I got back on the freeway, the temps dropped to the usual 180 water, but the oil temp dropped slowly. In the same heat if I avoid traffic, the water stays below 180 and the oil about 200.
The Cats sit astride the engine, very near the oil filter and pan. My theory is that the LT1 cats are cooking the oil, which in turn drives up the water temps in traffic. On a ZR 1 or L98, or (most other cars for that matter) the cats are downstream and cook only the transmission.
I've wondered if a LT1 with long headers and dual cats after the headers would intrinsically run cooler in traffic. I've also wondered if hood louvers would allow better radiator air flow in traffic.
Anyone have any first hand experience with LT1 long headers and traffic temps. Just curious.
When I got back on the freeway, the temps dropped to the usual 180 water, but the oil temp dropped slowly. In the same heat if I avoid traffic, the water stays below 180 and the oil about 200.
The Cats sit astride the engine, very near the oil filter and pan. My theory is that the LT1 cats are cooking the oil, which in turn drives up the water temps in traffic. On a ZR 1 or L98, or (most other cars for that matter) the cats are downstream and cook only the transmission.
I've wondered if a LT1 with long headers and dual cats after the headers would intrinsically run cooler in traffic. I've also wondered if hood louvers would allow better radiator air flow in traffic.
Anyone have any first hand experience with LT1 long headers and traffic temps. Just curious.
Thread Starter
Racer
Joined: Jun 2002
Posts: 428
Likes: 0
From: Dallas Tx
Re: Why is the LT1 so hot in traffic? (Alex D)
Thanks to all who replied. I do have a 160 thermostat. Sounds like I need to R & R the radiator assy and make sure the condenser and radiator are not clogged with sand, straw, etc.
I also noticed that my spoiler is in bad shape. I can feel hot air coming forward to recycle thru the radiator when I am stopped. I'll replace that also and see what happens.
Thanks again.
I also noticed that my spoiler is in bad shape. I can feel hot air coming forward to recycle thru the radiator when I am stopped. I'll replace that also and see what happens.
Thanks again.
