Losing RWHP with MODS..
Racer
Joined: Aug 2006
Posts: 446
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From: Orlando Fl
10 hp increase from replacing your shorties with the Bassani headers at the same time as you went from a 3:15 to a 3:42 gear is not bad at all. The gear change causes a loss of some hp but I bet the car woke up. What surprises me is a drop in tq with those headers. Are they the Tri Y's? Do you have an X pipe. Those headers usually make great torque.
Team Owner
Joined: Mar 1999
Posts: 22,025
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From: At the beach in little Rhody
Can you post the dyno curves? I agree that the cam change would net minor gains, although there may be more area under the curve. Is each dyno done with the converter locked? The FAST 78, properly ported, should net you about 15-18 hp. Careful of the Patriot heads as well, what is their port size? You might pick up peak numbers and lose low end fun.
Have you done any dynamic compression ratio calculations? What is your current compression ratio (static)? Where are you trying to make the power? Be careful of changing things between dynoes (motor parts/gears) as you can easily lose track of what is happening.
Have you done any dynamic compression ratio calculations? What is your current compression ratio (static)? Where are you trying to make the power? Be careful of changing things between dynoes (motor parts/gears) as you can easily lose track of what is happening.
Thread Starter
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
10 hp increase from replacing your shorties with the Bassani headers at the same time as you went from a 3:15 to a 3:42 gear is not bad at all. The gear change causes a loss of some hp but I bet the car woke up. What surprises me is a drop in tq with those headers. Are they the Tri Y's? Do you have an X pipe. Those headers usually make great torque.
First dyno was the best with the mods... The headers are Tri "Y".. I have the "X" pipe and hi-flo cats ZO6 Ti exhaust.I think it's the dyno or operator.
Thread Starter
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
Can you post the dyno curves? I agree that the cam change would net minor gains, although there may be more area under the curve. Is each dyno done with the converter locked? The FAST 78, properly ported, should net you about 15-18 hp. Careful of the Patriot heads as well, what is their port size? You might pick up peak numbers and lose low end fun.
Have you done any dynamic compression ratio calculations? What is your current compression ratio (static)? Where are you trying to make the power? Be careful of changing things between dynoes (motor parts/gears) as you can easily lose track of what is happening.
Have you done any dynamic compression ratio calculations? What is your current compression ratio (static)? Where are you trying to make the power? Be careful of changing things between dynoes (motor parts/gears) as you can easily lose track of what is happening.
I took off the FAST 78 and replaced it with the LS6.
I have no idea of the compression ratio calculation/current compression static.
Dyno 1 with the shortie headers and ZO6 cam and heads.
Max power 349.31 Max TQ 351.11
Dyno 2 after replacing the shorties with Bassini LT headers:
Max power 359.66 Max tq. 344.22
Dyno 3 after 224/224/ .567.567 LSA114 cam installed
Max Power 360.69 Max TQ 344.16
Final dyno by first tuner
376 RWHP and 350 RWHP
I hope you can make sence of this.
It look like a bad tune or dyno.
Last edited by SLPRC5; Apr 13, 2007 at 12:35 AM.
Team Owner
Joined: Mar 1999
Posts: 22,025
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From: At the beach in little Rhody
Where was the first dyno done, can you go back there and get a pull for comparison. Otherwise, to figure it out you would need to convert them all to a consistent scale and plot them with Excel. Different dynoes will give different results as well. I have been told the one I use in Mass is stingy on the numbers, not sure if it is true or not, but it works well as a parametric tuning tool.
Thread Starter
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
Where was the first dyno done, can you go back there and get a pull for comparison. Otherwise, to figure it out you would need to convert them all to a consistent scale and plot them with Excel. Different dynoes will give different results as well. I have been told the one I use in Mass is stingy on the numbers, not sure if it is true or not, but it works well as a parametric tuning tool.
I'm trying to decided if to go back to the first dyno place before installing the heads or wait until I have the heads installed to see how the number vary between the two dynos. I know the first pulled up my dyno numbers from 322 RWHP from a street tune to the 349.31 RWHP (this was after he installed a '98 pcm program into my '97 pcm)
Thislast tunner may have a problem tunning a A4..because he does a lot of M6s.
Last edited by SLPRC5; Apr 8, 2007 at 07:05 PM.
Team Owner
Joined: Mar 1999
Posts: 22,025
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From: At the beach in little Rhody
If its easily accessible, I would just go to the first place and have them do a pull to baseline the car from where you are now prior to doing the heads. This would help remove variables later when you are trying to figure out what you have gained.
Thread Starter
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
Thanks Buddy, you have always led me and others in the right direct.I'll try and setup one this week with the first dyno guy.
Hope you and your family had a Happy Easter
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Le Mans Master
Joined: Aug 2003
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From: American Canyon Lethal Injection
Drifting
Joined: Aug 2005
Posts: 1,836
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From: Sacramento Ca
Maybe it is something in your transmision or a problem with your torque converter. As long as it feels stronger all is well. Do you ever take your car to the track? Any improvement in 1/4 times?
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Le Mans Master
Joined: Aug 2003
Posts: 9,298
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From: American Canyon Lethal Injection
Never have gone to the track..but been told that is where to tell the gains. One guy who has driven my car and is track junkie says he bet my car is in the high 11s on street tires...
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Le Mans Master
Joined: Aug 2003
Posts: 9,298
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From: American Canyon Lethal Injection
Thread Starter
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
Much better numbers in RWHP and RWTQ after tune done today by my first tuner in 06.
I gained 16 RWHP and 5RWTQ on this tune.
The tune before this one was tuned too rich along with some other incorrect settings.
Here is the printout of today's dyno on the same dyno and tuner that was used for the first dyno.
I gained 16 RWHP and 5RWTQ on this tune.
The tune before this one was tuned too rich along with some other incorrect settings.
Here is the printout of today's dyno on the same dyno and tuner that was used for the first dyno.
Last edited by SLPRC5; Apr 12, 2007 at 02:59 AM.
Thread Starter
Le Mans Master
Joined: Aug 2003
Posts: 9,298
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From: American Canyon Lethal Injection
Glad you are enjoying the shorties
Next is the Patriot heads to be installed and another tune...this should get me over the 400RWHP I'm looking to get.
The tuner told me today he just did a Camaro A4 with the Patriot heads, LTs and the same cam I have and it got 427 RWHP.
SLPRC5
BTW great looking home page..
Last edited by SLPRC5; Apr 12, 2007 at 01:45 AM.
Melting Slicks
Joined: May 2005
Posts: 3,394
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From: Leon Iowa
St. Jude Donor '06-'07-'08-'09
something i don't understand, as posted earlier about losing HP with lower gears, How can that be? If anything I would think it would gain HP with lower gears. It sure feels like it anyway. Can somebody explain this to me?....Marc
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Le Mans Master
Joined: Aug 2003
Posts: 9,298
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From: American Canyon Lethal Injection