Lost HP?
Thread Starter
Pro
Joined: Dec 2005
Posts: 688
Likes: 0
From: las Vegas N.V.
Lost HP?
Lost 20 to 30 hp
My car is down about 20 to 30hp and about 25tq.
The motor is a ls6 with forged rods and pistons. TF 215 heads and a fast 102 and 90TB. Cam is a 233/239 .
Motor has about 6K miles on it.
It made 448hp and 407Tq on RPM's dyno about 8 months ago. Now it is making 425 and 380.
I put new plugs and wires in it recently and new O2 sensors. The dyno numbers were on two different dyno's out here in Vegas. The low numbers were verified by being down about 3mph at the track.
We made about 6 pulls on the dyno on Monday. Nothing indicates a problem. Fuel is good. It isn't pulling timing . No knock.
Also there is no smoke or oil loss.
The next step would be to do a compression test.
Any ideas?
My car is down about 20 to 30hp and about 25tq.
The motor is a ls6 with forged rods and pistons. TF 215 heads and a fast 102 and 90TB. Cam is a 233/239 .
Motor has about 6K miles on it.
It made 448hp and 407Tq on RPM's dyno about 8 months ago. Now it is making 425 and 380.
I put new plugs and wires in it recently and new O2 sensors. The dyno numbers were on two different dyno's out here in Vegas. The low numbers were verified by being down about 3mph at the track.
We made about 6 pulls on the dyno on Monday. Nothing indicates a problem. Fuel is good. It isn't pulling timing . No knock.
Also there is no smoke or oil loss.
The next step would be to do a compression test.
Any ideas?
Last edited by Zosixin; Jan 24, 2012 at 09:46 PM.
Supremacy 1 car at a time
Joined: Jun 2010
Posts: 1,186
Likes: 5
From: Sandbox KUW
my car lose the same then I got my blown engine and that was a 2 years ago! hope it's not the same, it's my the dyno not reading well I still remember a dyno shop we get numbers like 610whp we pick the car out and run at the same night on another mustang dyno we got 586whp.
good luck
good luck
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Do you guys get winter blend fuel in LV? If so, there is the difference. It will be about 5%. I found the same thing with two dyno sessions the only difference being summer vs. winter blend fuel. Once the summer blend came back the power returned to the original level. On my car, the dyno curve was parallel but lower with the winter fuel. If I upped it by just under 5% the two curves laid on top of each other.
Le Mans Master
Joined: Sep 2006
Posts: 9,100
Likes: 166
From: PA
This one can be a mystery for the making. I've had 2 cars do similar things heres what I went through with no answer to why the power loss or trap speed loss.
Compression check
Leak down check
Plugs replaced
wires replaced
cleaned MAF electrodes (Carefully)
changed valve springs
checked for brake drag
changed trans/rear diff fluids
had tuned and retuned
made sure dynoed with same wheels/tires
same dyno every time with same SAE settings
took serpentine belt off and spun all accessories
tried 100 octane gas
ran seafoam cleaner through injection system
checked for intake gasket leaks
tried thinner oil 0w30 vs 5w30
Pretty much only thing left was a possible clutch slippage
Compression check
Leak down check
Plugs replaced
wires replaced
cleaned MAF electrodes (Carefully)
changed valve springs
checked for brake drag
changed trans/rear diff fluids
had tuned and retuned
made sure dynoed with same wheels/tires
same dyno every time with same SAE settings
took serpentine belt off and spun all accessories
tried 100 octane gas
ran seafoam cleaner through injection system
checked for intake gasket leaks
tried thinner oil 0w30 vs 5w30
Pretty much only thing left was a possible clutch slippage
Le Mans Master
Joined: Aug 2007
Posts: 6,471
Likes: 296
From: Orange Park FL
I had a loss of power I never figured out. Two different Dynos put my 402 Stroker at 464 rwhp & 465 rwhp, torque was near 450.
Jump to a year later, retune and it shows 445 rwhp, 413 tq. Freaking out, I Checked on another dyno and again on the original...all show 445 area and only 413 torque.
That is 20 lost hp and 37 tq. I take it to the track and I am running as strong as ever. I am actually up 1 mph and a couple thousandths lower ET.
THIS STILL BLOWS MY MIND.
Good luck...hope your is nothing
Jump to a year later, retune and it shows 445 rwhp, 413 tq. Freaking out, I Checked on another dyno and again on the original...all show 445 area and only 413 torque.
That is 20 lost hp and 37 tq. I take it to the track and I am running as strong as ever. I am actually up 1 mph and a couple thousandths lower ET.
THIS STILL BLOWS MY MIND.
Good luck...hope your is nothing
Le Mans Master
Joined: Aug 2007
Posts: 6,471
Likes: 296
From: Orange Park FL
Burning Brakes
Joined: Dec 2006
Posts: 958
Likes: 1
Compression check
Leak down check
cleaned MAF electrodes (Carefully)
changed valve springs
took serpentine belt off and spun all accessories
tried 100 octane gas
ran seafoam cleaner through injection system
checked for intake gasket leaks
tried thinner oil 0w30 vs 5w30
Pretty much only thing left was a possible clutch slippage
Leak down check
cleaned MAF electrodes (Carefully)
changed valve springs
took serpentine belt off and spun all accessories
tried 100 octane gas
ran seafoam cleaner through injection system
checked for intake gasket leaks
tried thinner oil 0w30 vs 5w30
Pretty much only thing left was a possible clutch slippage
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Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I did check the EPA web site. They don't use Butane like we get in the NE to alter the vapor pressure, however they do require other changes to the fuel in the winter months which is stated to reduce mileage. That being the case, if the fuel has less BTU per gallon it will affect the hp. I have done all of this on the dyno a few years ago and if you are making small changes and want to evaluate the results, the fuel can overshadow the numbers. For example, if one installed an UD pulley and then put the car on the same dyno as pre-installation were taken but with winter rather than summer blend fuel, the car will show no gain or possibly negative gain. With a high hp modified car, the numbers can be large (almost 5%). So for a 450 hp car, the hp would drop to around 425 hp.
Thread Starter
Pro
Joined: Dec 2005
Posts: 688
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From: las Vegas N.V.
Melting Slicks
Joined: Aug 2006
Posts: 2,205
Likes: 2
From: port monmouth nj
mix to fix also. the right amt of torco to up the octane to what it should be. i use it on race day to keep my detonation safe 1oz per gal is what i blend makes it right for me without bringing the octane up to high. if you mix 8oz torco with 5gal 93 octane supposedly you'll end up around 96octane. check torco's charts if you should use prior to mixing.
Thread Starter
Pro
Joined: Dec 2005
Posts: 688
Likes: 0
From: las Vegas N.V.
mix to fix also. the right amt of torco to up the octane to what it should be. i use it on race day to keep my detonation safe 1oz per gal is what i blend makes it right for me without bringing the octane up to high. if you mix 8oz torco with 5gal 93 octane supposedly you'll end up around 96octane. check torco's charts if you should use prior to mixing.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Octane is not the issue, its whether they blend other components as required by the EPA in the fuel you use. Octane is for knock but doesn't control BTU content.
I am not saying fuel is the issue, but I wouldn't rule it out without checking. You could end up spending a lot of time and effort digging into motor issues.
I am not saying fuel is the issue, but I wouldn't rule it out without checking. You could end up spending a lot of time and effort digging into motor issues.
