Supercharged 2001 c5 lower than expected power
Former Vendor
Joined: Feb 2012
Posts: 26,512
Likes: 351
From: ST. CHARLES IL
Last edited by JUICED1; Oct 14, 2020 at 09:30 AM.
Melting Slicks
Joined: Jul 2014
Posts: 2,356
Likes: 359
From: Virginia
14 is a very low number. Maybe on an LS3 car with a lot of boost we would be in that timing range. But LS1 cars like more timing then LS3 cars do and they also have less compression. Are you getting knock with more timing? Did they try to add any? Timing is power, if you're short on power and on timing it looks easy to me but those dyno graphs look awfully rough. I think you have some belt slip but you could be bleeding some boost as well or fighting a mechanical issue.
Burning Brakes
Joined: Oct 2005
Posts: 1,089
Likes: 82
From: Kauhava, Finland
While taking it to a new tuner, remember to ask BOTH before tune and after tune graphs. Just for us to review here. :-)
Burning Brakes
Joined: Oct 2005
Posts: 1,089
Likes: 82
From: Kauhava, Finland
Safety Car
Joined: Feb 1999
Posts: 4,044
Likes: 342
From: Central NJ
wow, that is higher than I even thought to test...Thanks for the feedback...As I like to tinker with the tune, I will try 1 degree at a time to see if my car will allow more timing without knock...I saw that on an actual dyno I was seeing knock which is why the timing was low....I am not sure if the street will make a difference over a dyno in this regard.....But I was always told that a good tuner will dyno tune then also tune on the street...not sure if this is accurate but it sounds feasible...
Melting Slicks
Joined: Jul 2014
Posts: 2,356
Likes: 359
From: Virginia
wow, that is higher than I even thought to test...Thanks for the feedback...As I like to tinker with the tune, I will try 1 degree at a time to see if my car will allow more timing without knock...I saw that on an actual dyno I was seeing knock which is why the timing was low....I am not sure if the street will make a difference over a dyno in this regard.....But I was always told that a good tuner will dyno tune then also tune on the street...not sure if this is accurate but it sounds feasible...
Yes, you should fine tune on the street once you're done on the dyno because a dyno is only a simulation of real world conditions. Once you get off the dyno you want to make sure the simulations were accurate and the changes made actually reflect what you are seeing while driving it as intended.
Le Mans Master
Joined: Mar 2006
Posts: 5,775
Likes: 585
From: Texas
wow, that is higher than I even thought to test...Thanks for the feedback...As I like to tinker with the tune, I will try 1 degree at a time to see if my car will allow more timing without knock...I saw that on an actual dyno I was seeing knock which is why the timing was low....I am not sure if the street will make a difference over a dyno in this regard.....But I was always told that a good tuner will dyno tune then also tune on the street...not sure if this is accurate but it sounds feasible...
Melting Slicks
Joined: Nov 2017
Posts: 2,306
Likes: 747
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Melting Slicks
Joined: Nov 2017
Posts: 2,306
Likes: 747
14 is a very low number. Maybe on an LS3 car with a lot of boost we would be in that timing range. But LS1 cars like more timing then LS3 cars do and they also have less compression. Are you getting knock with more timing? Did they try to add any? Timing is power, if you're short on power and on timing it looks easy to me but those dyno graphs look awfully rough. I think you have some belt slip but you could be bleeding some boost as well or fighting a mechanical issue.
Melting Slicks
Joined: Nov 2016
Posts: 2,310
Likes: 1,583
From: East Metro (Twin Cities) Minnesota
St. Jude Donor '21
V3Si here. Around 600 crank HP, car runs 130 trap speeds in the 1/4.
I was at about 14-15 degrees timing on 91 octane (with stock cam) and would get too many blips of KR for my liking. I switched to blending my fuel to make E33 and which is around 95 octane and I am at 17 degrees of timing now with NO KR.
If an engine really does not like timing (and is knock limited prior to making MBT), I would wonder if it has too much carbon buildup on the pistons or if there is a weak injector - which runs that cylinder a bit lean (less cooling) and causes KR. Just some thoughts.
Also, Headers are over rated on these cars when you are keeping the stock cats. For offroad use without cats they are worth it - especially with a 3" exhaust (instead of stock 2.5")
Here is the reasoning behind my headers statement.
Toys.
I was at about 14-15 degrees timing on 91 octane (with stock cam) and would get too many blips of KR for my liking. I switched to blending my fuel to make E33 and which is around 95 octane and I am at 17 degrees of timing now with NO KR.
If an engine really does not like timing (and is knock limited prior to making MBT), I would wonder if it has too much carbon buildup on the pistons or if there is a weak injector - which runs that cylinder a bit lean (less cooling) and causes KR. Just some thoughts.
Also, Headers are over rated on these cars when you are keeping the stock cats. For offroad use without cats they are worth it - especially with a 3" exhaust (instead of stock 2.5")
Here is the reasoning behind my headers statement.
Toys.
Last edited by Toys4Life C5; Oct 16, 2020 at 03:49 PM.
Racer
Joined: Aug 2006
Posts: 402
Likes: 85
From: Terre Haute Indiana
I had valve float when I initially dynoed mine after installing an ECS kit. Timing was in the 14-15* area. After discussing on here with some and the tuner (Mike Norris), we swapped out the stock springs with some single PACS. The next dyno after wards picked up close to 80 rwhp. Search for my name and look through the posts.
Melting Slicks
Joined: Nov 2016
Posts: 2,310
Likes: 1,583
From: East Metro (Twin Cities) Minnesota
St. Jude Donor '21
I had valve float when I initially dynoed mine after installing an ECS kit. Timing was in the 14-15* area. After discussing on here with some and the tuner (Mike Norris), we swapped out the stock springs with some single PACS. The next dyno after wards picked up close to 80 rwhp. Search for my name and look through the posts.
Toys.