997SC on the Dyno: 442 RWHP!
#31
03-19-2010, 11:50 AM
Registered User
Join Date: Aug 2004
Location: Chicagoland
Posts: 2,134
Rep Power: 122 
Don't believe everything you read.
#33
03-19-2010, 01:04 PM
Join Date: Jan 2007
Location: ATL
Posts: 1,953
Rep Power: 199 Behind the throttle plate via the same hose you are using I have a SPA digital boost sensor. It records a max of 6.1 PSI at red line with the 3.6 inch pulley. It recorded 4.5-4.7 PSI with the 3.8 inch pulley. (I have used rubber silicone sealant around all the piping so there should be no leaks.)
http://www.spatechnique.com/product_...ils.cfm?id=371
Comparing the 3.6 inch pulley to the previous 3.8 inch pulley shows an increase of approximately 1.5 PSI. (That is in line with Vortech’s claim of a 1-2 PSI increase with a one step down pulley size replacement. See below:
http://www.vortechsuperchargers.com/product.php?p=41
“Please Note
A change in one pulley size will usually effect boost 1-2 PSIG... down in diameter, up in boost and vice versa.”
In testing we found the X-51 header outperformed the Fabspeed I had previously. (The x-51 has a larger diameter) We also found that putting a high velocity fan pointed directly into the engine compartment to simulate the airflow normally created in motion increased HP also as well as lowered charge air temps. (No sucking in superheated air)
As for the G-Tech I could not get it to produce consistent results. I may have been doing something wrong; it just did not work for me. I also had a problem getting my Durametric cable to work. It would show a short in the system and shutdown my engine. The Porsche PWIS could not find any faults however. Since I have easy access to the PWIS I have not tried to figure out the Durametric.
As for the HP number shown by the DYNO I don’t really care what it says. I was and am more interested in what it drives like via the butt dyno. The car is very fast and I am very happy with the results. I wanted to up the performance to a level I would be happy with and then simply drive the car. I won’t argue the validity of this dyno’s numbers or accuracy because I have no idea. I can only tell you what was recorded at what date. The previously shown dyno was a comparison of the different size pulleys. Also, since my car is a 4 wheel drive I also took it to a 4 wheel drive Mustang dyno and it recorded 404 HP. How does that compare? Don’t know and don’t really care. Different dyno’s, different days, different ambient conditions all result in different numbers.
If I was interested in more performance I would not personally increase the boost from my current amount or add new mods but just go purchase a 997TT and mod it. (Yes I could afford one) So this is not a competition. I usually pick a project, finish it and move on. My latest was installing Laser Interceptor laser jammers on my Cayenne Turbo S.
My next project is to DE the 997 next month. I still lurk and am interested in your results but my engine modding program is complete.
Walt
http://www.spatechnique.com/product_...ils.cfm?id=371
Comparing the 3.6 inch pulley to the previous 3.8 inch pulley shows an increase of approximately 1.5 PSI. (That is in line with Vortech’s claim of a 1-2 PSI increase with a one step down pulley size replacement. See below:
http://www.vortechsuperchargers.com/product.php?p=41
“Please Note
A change in one pulley size will usually effect boost 1-2 PSIG... down in diameter, up in boost and vice versa.”
In testing we found the X-51 header outperformed the Fabspeed I had previously. (The x-51 has a larger diameter) We also found that putting a high velocity fan pointed directly into the engine compartment to simulate the airflow normally created in motion increased HP also as well as lowered charge air temps. (No sucking in superheated air)
As for the G-Tech I could not get it to produce consistent results. I may have been doing something wrong; it just did not work for me. I also had a problem getting my Durametric cable to work. It would show a short in the system and shutdown my engine. The Porsche PWIS could not find any faults however. Since I have easy access to the PWIS I have not tried to figure out the Durametric.
As for the HP number shown by the DYNO I don’t really care what it says. I was and am more interested in what it drives like via the butt dyno. The car is very fast and I am very happy with the results. I wanted to up the performance to a level I would be happy with and then simply drive the car. I won’t argue the validity of this dyno’s numbers or accuracy because I have no idea. I can only tell you what was recorded at what date. The previously shown dyno was a comparison of the different size pulleys. Also, since my car is a 4 wheel drive I also took it to a 4 wheel drive Mustang dyno and it recorded 404 HP. How does that compare? Don’t know and don’t really care. Different dyno’s, different days, different ambient conditions all result in different numbers.
If I was interested in more performance I would not personally increase the boost from my current amount or add new mods but just go purchase a 997TT and mod it. (Yes I could afford one) So this is not a competition. I usually pick a project, finish it and move on. My latest was installing Laser Interceptor laser jammers on my Cayenne Turbo S.
My next project is to DE the 997 next month. I still lurk and am interested in your results but my engine modding program is complete.
Walt
I just can't figure out why we'd get the same boost (6.1 psi) from 2 different pulleys. If you got that HP from the 3.6, I wonder what you'd get from the 3.4 I am running? I know my numbers are accurate, but yours are a little odd, hence, my questions. Regardless, as I said, if your butt dyno is happy, enjoy, I salute you!As for the higher velocity fan, that sounds smart. I know that 1999 has a fan mod, but what did you install? Can you share some photos? I live in ATL, and with the hot summer approaching, I'd like to look into any add'l cooling options.
CATTMAN
Last edited by Cattman; 03-19-2010 at 01:09 PM.
#34
03-19-2010, 01:14 PM
Cattman,
The fan is not a mod. Open the deck lit, get a big high power fan, they have them at the dyno shop, and place it so that the air is blown into the engine compartment. You can use fans similar to the ones they should already be placing in front of the radiators in the front bumper.
The fan is not a mod. Open the deck lit, get a big high power fan, they have them at the dyno shop, and place it so that the air is blown into the engine compartment. You can use fans similar to the ones they should already be placing in front of the radiators in the front bumper.
#35
03-19-2010, 01:19 PM
Registered User
Join Date: Aug 2004
Location: Chicagoland
Posts: 2,134
Rep Power: 122 Cattman,
The fan is not a mod. Open the deck lit, get a big high power fan, they have them at the dyno shop, and place it so that the air is blown into the engine compartment. You can use fans similar to the ones they should already be placing in front of the radiators in the front bumper.
The fan is not a mod. Open the deck lit, get a big high power fan, they have them at the dyno shop, and place it so that the air is blown into the engine compartment. You can use fans similar to the ones they should already be placing in front of the radiators in the front bumper.
Do you tow that fan behind the car with the lid open to insure that your artificial numbers remain constant?
#36
03-19-2010, 02:04 PM
Join Date: Jan 2007
Location: ATL
Posts: 1,953
Rep Power: 199 Haha. I thought he meant he installed a higher velocity engine bay fan, something I may do. That, or 1999's fan mod. Personally, I didn't use any fans for my dyno, we went au natural, 67 degree ambient temp.
1999: take a look at my AFR, let me know what you see.
CATTMAN
#38
03-19-2010, 03:45 PM
1999, curious if you know off hand how much boost the 3.33" and the 3.4" pulleys produce on a 3.4l. I just ordered both. Strange thing was when my mechanic took the old pulley off it was a 3.48". Ithought it came with a 3.6" from EVO.
#40
03-19-2010, 04:29 PM
Stacy
#41
03-19-2010, 04:49 PM
. I thought I would make more than 6psi with the 3.48"?
#43
03-19-2010, 05:24 PM
I am using a hand held gauge NOT digital so getting the exact PSI while rippin down the street at 100 mph can be challenging LOL.....BUT
3.8" 3.8 PSI(hand held and dyno measured)
3.6" 4.6 PSI
3.48" 5.2 PSI
3.4" 6 PSI(hand held and dyno measured)
3.33" (never tried BUT was NEXT) and I was thinking it would do 6.6 or 6.7 PSI
I am going to guess a 3.33 will make a hair over 7 PSI(7.2 PSI) for you!
Stacy
Last edited by justatoy; 03-19-2010 at 05:29 PM.
#44
03-19-2010, 05:30 PM
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Join Date: Aug 2004
Location: Chicagoland
Posts: 2,134
Rep Power: 122 The fan makes a huge difference in the dyno numbers.....higher. Remember that normal intake temps can be as much as 50+F higher than ambient with lid closed.
#45
03-19-2010, 06:21 PM
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Join Date: Aug 2004
Location: Chicagoland
Posts: 2,134
Rep Power: 122 Boost depends on engine size. Bigger engine produces less boost. Size and length of tubes also effect final boost as well as engine spread. I have run as high as 10# and currently am running 9+.
The standard 3.8" pulley on the 3.4 engine produces 5.8 psi at 7300 rpm.