Hot under the Hood
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
Originally Posted by PMARTINEZ92126
Im sure this question has come up a few times but I couldnt find a post on "under hood temperatures". ......... I also have TPIS coated headers and Dart Pro alum heads. After the car has warmed up I will sometimes open the hood only to find that it is as hot as an oven. ........... Is there anything I can do to bring the temp down in the engine bay? 
Melting Slicks
Joined: May 2004
Posts: 2,524
Likes: 10
From: Lufkin Texas
St. Jude Donor '05-'06
I dont get it? 
He has coated TPIS. My ceramic coated Hookers with freeflow exhaust run cooler than the stock manifolds. I can actually touch them within 20 minutes or so after driving. They run so cool I'm considering a heated o2 sensor. Then again, I'm still just basicly a stock L98 lightly modded with a little juice.
I just cant help but believe there's something up with the tune. I just dont think it's all the headers fault if they're coated with a high flow cat.
By the way PMARTINEZ92126, you do have a good flowing cat, right? If you have an older/clogged stock cat, they can cause heat issues as well as poor performance.
He has coated TPIS. My ceramic coated Hookers with freeflow exhaust run cooler than the stock manifolds. I can actually touch them within 20 minutes or so after driving. They run so cool I'm considering a heated o2 sensor. Then again, I'm still just basicly a stock L98 lightly modded with a little juice. I just cant help but believe there's something up with the tune. I just dont think it's all the headers fault if they're coated with a high flow cat.
By the way PMARTINEZ92126, you do have a good flowing cat, right? If you have an older/clogged stock cat, they can cause heat issues as well as poor performance.
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
Originally Posted by skateparkdave
I just cant help but believe there's something up with the tune. I just dont think it's all the headers fault if they're coated with a high flow cat.
.
.
Melting Slicks
Joined: May 2004
Posts: 2,524
Likes: 10
From: Lufkin Texas
St. Jude Donor '05-'06
Originally Posted by LT4BUD
A bad tune can certainly make it much worse.......but I just believe my unhood temps are definitely up since I installed the EM coated long tube headers....new high flow cats...
Guess I'm glad I went with ceramic coated Hooker super comps that are coated inside and out. Maybe thats the difference. I'm not sure, I just know mine run surpisingly cool.
Le Mans Master
Joined: Feb 1999
Posts: 9,926
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
Originally Posted by LT4BUD
A bad tune can certainly make it much worse.......but I just believe my unhood temps are definitely up since I installed the EM coated long tube headers....new high flow cats...
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
Originally Posted by steve40th
A retune is , IMHO a necessary thing after putting in long tube headers. Do a scan and see you are running different after the headers.
Thread Starter
Racer
Joined: Sep 2002
Posts: 420
Likes: 1
From: SAN DIEGO CA
i will check the timing tonight. I also have one of those laser heat testing guns. You can point it at a source and it will tell you the temp of the part. Is there a way to check to see if the Cat is clogged? I do remember smelling gas after I started the car. That went away after I changed out my FPR. The diaphram was shot. At idle the car will run about 198 degrees with the temp outside being 68 degrees. I have a 160 t-stat in the car. I have a Stewart pump with a regular Radiator.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Melting Slicks
Joined: May 2004
Posts: 2,524
Likes: 10
From: Lufkin Texas
St. Jude Donor '05-'06
Originally Posted by PMARTINEZ92126
Is there a way to check to see if the Cat is clogged?
To test for a plugged converter, drill a small hole in the exhaust pipe right before the catalytic converter. Install a temporary hose fitting and attach a long rubber hose and a 0 to 10 pound pressure gauge. With the gauge inside the car, drive up a hill or accelerate and read the pressure. Normal is 2 to 3 pounds, restricted 4 pounds or higher. The drawback to this method is the small hole will need to be welded shut after the test; a minor job if you have a welder.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
My back pressure gauge came with devices that are like nut-serts.
You drill the pipe, install the device, test and then seal the device
with a short hex bolt.
Other gauges fit into the O2 sensor bung.
.
You drill the pipe, install the device, test and then seal the device
with a short hex bolt.
Other gauges fit into the O2 sensor bung.
.
Racer
Joined: Oct 2005
Posts: 264
Likes: 1
From: La Grande Oregon
You can use your thermo gun to test the cats, get the car warmed up as much as possable, the hotter you can get the cats the better, take a reading before the cat,and after, if they are close to the same then it's working, if not then it's plugged or plugging. The hard part is to get the car up in the air before the cats start cooling off.
Thread Starter
Racer
Joined: Sep 2002
Posts: 420
Likes: 1
From: SAN DIEGO CA
This little gun has a laser so Im thinking i might be able lay on the ground and shoot the front and back of the cat with the laser while the car is running. Hopefully I wont get burned or run over. I will do it this Saturday. Thanks for the Help.
Racer
Joined: Jan 2005
Posts: 476
Likes: 0
From: Tucson, AZ. L98-85 AUTO COUPE: 120k MILES: daily driver. SOUND OFF IF YOU'VE BEEN THERE. Ex-Jumpin' Junky-82nd Airborne-2/505 PIR: 1st ID-1/16th Inf: Recon Marine Retread. GOD BLESS GRUNTS.
those hood vents have to be a good thing. they take air passing under the car-that could make the front end light-pass it around the motor and push it onto the top of the car-to help push the front end down.
take a look at a lot of BIG buck cars(like the new ford gt, saleen etc.), and they have the same set-up. i'm seriously considering going for the louvers. true, water drainage is an issue, but it shouldn't be accomplished at the cost of flow. has anybody seen how the supercars handle the drainage issue?
i'm taking a look right now. but if i remember past considerations, TALK ABOUT A CORVETTE TAX.
frog.
take a look at a lot of BIG buck cars(like the new ford gt, saleen etc.), and they have the same set-up. i'm seriously considering going for the louvers. true, water drainage is an issue, but it shouldn't be accomplished at the cost of flow. has anybody seen how the supercars handle the drainage issue?
i'm taking a look right now. but if i remember past considerations, TALK ABOUT A CORVETTE TAX.
frog.
Thread Starter
Racer
Joined: Sep 2002
Posts: 420
Likes: 1
From: SAN DIEGO CA
Cat
I checked the temperature of my CAT using a Matco LT1000 heat gun. The temperature right before the CAT was roughly 240 F. and the Temperature after the CAT was roughly 450 F. I did the test several times. I also checked to make sure the coolant gauge was accurate and it was to off about 3 degrees from what the Heat gun told me so Im assuming the gun is fine. My timing was definitely off. It was advanced by 4-6 degrees so I changed it back to 6 degree before BTC. The coolant reading was 186 degrees after it had been idlling for 15 minutes. Why would the cat temperature be so different on the way in as opposed to the way out? I did have a bad AFPR that was leaking fuel in the plenum. I guess the fuel was being sucked into the plenum. I saw a little discoloration fuel trail on the inside of the plenum where the fuel had been sucked in. The AFPR had been bad for some time.
Safety Car
Joined: Feb 2005
Posts: 4,721
Likes: 1
From: Beautiful Down Town "SWINDLEHURST" Long Island NY
Originally Posted by parafrog
those hood vents have to be a good thing. they take air passing under the car-that could make the front end light-pass it around the motor and push it onto the top of the car-to help push the front end down.
take a look at a lot of BIG buck cars(like the new ford gt, saleen etc.), and they have the same set-up. i'm seriously considering going for the louvers. true, water drainage is an issue, but it shouldn't be accomplished at the cost of flow. has anybody seen how the supercars handle the drainage issue?
i'm taking a look right now. but if i remember past considerations, TALK ABOUT A CORVETTE TAX.
frog.
take a look at a lot of BIG buck cars(like the new ford gt, saleen etc.), and they have the same set-up. i'm seriously considering going for the louvers. true, water drainage is an issue, but it shouldn't be accomplished at the cost of flow. has anybody seen how the supercars handle the drainage issue?
i'm taking a look right now. but if i remember past considerations, TALK ABOUT A CORVETTE TAX.
frog.
. My only problem is the hood ducting is open, when you look into the louvers you can see in the ducts. A small piece of sheet alum. in the spring will fix that.When I first got the vette any thing over 100mph-( on my local closed track
)felt very unstable. Now with the louvers and the new "Z-51"-ish chin spoiler ( 3" ground clearance-no more fast food joints 
) Its rock solid at speed ( 11.66 squared) 
And no cooling problems.
:PS---I looked at your profile--101st-5th. Div. out of "Dodge City" Here--
: 
Last edited by RICEKILA; Feb 26, 2006 at 06:15 PM.