Notices
928 Forum 1978-1995
Sponsored by:
Sponsored by: 928 Specialists

Supermodel Dyno

Thread Tools
 
Search this Thread
 
Old Jul 18, 2005 | 09:45 PM
  #61  
Jim_H's Avatar
Jim_H
Banned
 
Joined: May 2001
Posts: 12,264
Likes: 3
From: The Great Northwest
Default

That dyno chart looks a lot like mine. Woody's has more boost and a bit more torque.

post 173
https://rennlist.com/forums/showthre...&page=14&pp=15
Reply
Old Jul 19, 2005 | 12:04 AM
  #62  
all4woody's Avatar
all4woody
Thread Starter
Racer
 
Joined: May 2005
Posts: 267
Likes: 1
From: Fountain Inn, SC
Default

Sniper,
That's the point. Nobody was trying to decieve anyone. The first dyno had some strange numbers, so I went to another dyno. In the end, there was only a 10rwhp difference.
Reply
Old Jul 19, 2005 | 03:00 AM
  #63  
m21sniper's Avatar
m21sniper
Banned
 
Joined: Jul 2005
Posts: 2,066
Likes: 1
From: Philly
Default

What were your exact before and after(revised) power numbers?

Just curious.
Reply
Old Jul 19, 2005 | 10:34 AM
  #64  
Lagavulin's Avatar
Lagavulin
Three Wheelin'
 
Joined: Mar 2003
Posts: 1,286
Likes: 1
From: New Berlin
Default

Originally Posted by all4woody
Lagavulin,
I originally posted my dyno sheet on this board to get some positive feedback and some backslaps from my "friends" in the Porsche community.

It seems all you did was figure out ways to discredit my hard work, instead of giving helpful suggestions to correct the problem (which I expect from this forum).
Woody, I am a hard-core technical guy, and I'm giving you technical feedback which you may not like to hear. It is not a slam on you. But listen to what I am saying, and to what your first posted dyno sheet is saying; everything you need to know is right there in front of you.

One last time. There is no way a second dyno run can come close to an initial dyno run whose SAE Correction Factor was 1.16. Look at the atmospheric readings and SAE Correction Factor of your initial baseline run versus your 'after' run.

Go back and do the calculations yourself, that is why I always post the simple formulas so that anyone can take them and experiment with whatever numbers they choose. The numbers themselves do not lie, and the 1.16 CF stands out like a sore-thumb to those who can 'see'.

At the very least, you will learn more than you counted on prior to your post!
Reply
Old Jul 19, 2005 | 02:30 PM
  #65  
Fastest928's Avatar
Fastest928
Rennlist Member
 
Joined: Mar 2002
Posts: 1,617
Likes: 1
From: California
Default

Wow,

Woody Says "That's the point. Nobody was trying to decieve anyone. The first dyno had some strange numbers, so I went to another dyno. In the end, there was only a 10rwhp difference."

That says it all!

We now have folks on the list who defy the physics of the day ... Jim H, Woody and ..... who is next??

Have fun guys.
Reply
Old Jul 19, 2005 | 08:22 PM
  #66  
all4woody's Avatar
all4woody
Thread Starter
Racer
 
Joined: May 2005
Posts: 267
Likes: 1
From: Fountain Inn, SC
Default

Lag,
There you go again cutting and pasting only what you want people to see. This puts a slant on things. Why not past my second sentence "There were some indiscretions with the dyno setup".

Anyone else, read my post on the previous page. I'm done with this BS. Woody.
Reply
Old Jul 20, 2005 | 08:51 AM
  #67  
Lagavulin's Avatar
Lagavulin
Three Wheelin'
 
Joined: Mar 2003
Posts: 1,286
Likes: 1
From: New Berlin
Default DYNO-GATE

Originally Posted by all4woody
Lag,
There you go again cutting and pasting only what you want people to see. This puts a slant on things. Why not past my second sentence "There were some indiscretions with the dyno setup".

Anyone else, read my post on the previous page. I'm done with this BS. Woody.
Okay, then let me spell this out for you.

Here is a dyno-sheet of THE BEST 928 twin-screw installation on the planet as of today, running 9lbs of boost:

http://members.rennlist.com/v1uhoh/perfnumbers.htm

Firstly, note the 'normal' SAE Correction Factor of 1.05.

Now look at the power output at 9 psi: 402 rwhp.

Tony's running an automatic, so what would he theoretically do if he had a manual?

Using 80% drivetrain loss for auto:
chp = rwhp / .80
chp = 402 / .80 = 502.5 crank hp, a very gain over stock

Now, what would the rwhp be with a manual using 85% loss?

rwhp = (crank hp) x (drivetrain loss)
rwhp = 503 x .85 = 427.6 rwhp

So somehow, you put out more power with 7.5 psi than Tony's car at 9 psi!

Taking this one step further, let's do the calcs I did earlier with your numbers using Tony's results, again, to make it simple, we'll ignore thermal losses.

First we find the Pressure Ratio (..PR)
PR = (boost + 14.7) / 14.7
PR = (9psi + 14.7psi) / 14.7psi = 1.6

Using the PR, we'll find the Forced Induction horsepower (..FI-HP)
FI-HP = (crank hp) x PR
FI-HP = 320 chp x 1.6 = 512 chp (..does that number look vaguely familiar?)

Finally, the rwhp with both an automatic and a manual:

rwhp = (crank hp) x (drivetrain loss)
rwhp = 512 chp x .85 = 435.2 rwhp for a manual
rwhp = 512 chp x .80 = 409.6 rwhp for an automatic

The bottom line: Tony's dyno clocks in with what the numbers say it should. The optimistic 410 rwhp is a near dead-ringer for his listed 402 rwhp. On the other hand, your numbers are not even close.

Concluding, it looks like we have a DYNO-GATE on our hands!

"There were some indiscretions with the dyno setup".
Yes, it's rather obvious.
Reply
Old Jul 20, 2005 | 11:04 AM
  #68  
GoRideSno's Avatar
GoRideSno
Drifting
 
Joined: Feb 2002
Posts: 2,015
Likes: 0
From: Redondo Beach, CA>>>>Atlanta,GA
Default

Lag,
Tony's system is the best looking, I'll give you that. Tony's setup is the best for you because it puts out lower HP per psi boost than any of my setups that have been dynoed. So I am sure you love it for that reason. I put out as much HP with The Jag/Eaton system at 8.5psi on my car as Tony's setup did. Could be his transmission, or something else.

So once again you try to use twisted information to support your belief that you you are more intelligent and superior.

For a small consulting fee you can get the proper information about the thermal efficency of the twin-screw from Corky Bell. Please do this before you develop health problems worrying about how the twin-screws can support as much power as they do.

You need to point out where I threatened you over on the other thread too.

Sincerely,
Andy Keel

Last edited by GoRideSno; Jul 21, 2005 at 12:42 AM.
Reply
Old Jul 20, 2005 | 01:21 PM
  #69  
Fastest928's Avatar
Fastest928
Rennlist Member
 
Joined: Mar 2002
Posts: 1,617
Likes: 1
From: California
Default

Tony has lower compression with his setup. He machined his pistons ...quite nicely I must add!

Marc
Reply
Old Jul 20, 2005 | 06:42 PM
  #70  
Herr-Kuhn's Avatar
Herr-Kuhn
Banned
 
Joined: Apr 2005
Posts: 716
Likes: 0
Default

Hey, maybe I should hire "Speed Racer" for my calculating needs? Next year, NC...
Reply
Old Jul 20, 2005 | 07:05 PM
  #71  
DR's Avatar
DR
Rennlist Sponsor
Rennlist
Site Sponsor

 
Joined: Jun 2001
Posts: 4,306
Likes: 12
From: Tampa, Florida
Default

>Next year, NC...

Already have a portable DynoJet arranged for next years Sharks in the Mountains :-)
__________________
David Roberts
2010 Jaguar XKR Coupe - 510HP Stock - Liquid Silver Metallic
928 Owners Club Co-Founder
Rennlist 928 Forum Main Sponsor
www.928gt.com

928 Specialists on Facebook - 928Specialists
Sharks in the Mountains on Facebook - 928SITM

Reply
Old Jul 20, 2005 | 08:52 PM
  #72  
Mark Anderson's Avatar
Mark Anderson
The Parts Whisperer
Rennlist
Site Sponsor

20 Year Member
 
Joined: Nov 2002
Posts: 7,231
Likes: 527
From: Anaheim Ca
Default

Originally Posted by marc@DEVEK
Tony has lower compression with his setup. He machined his pistons ...quite nicely I must add!

Marc
I don't think those pistons are in his motor.
Reply
Old Jul 20, 2005 | 09:30 PM
  #73  
all4woody's Avatar
all4woody
Thread Starter
Racer
 
Joined: May 2005
Posts: 267
Likes: 1
From: Fountain Inn, SC
Default

Beating a dead horse. Is the discussion that 460rwhp can't be made, or that it can't be made by a twin-screw? The Murph kit, which was one of my other choices, put down 463 with the same setup as mine.
Reply
Old Jul 20, 2005 | 09:46 PM
  #74  
Jim_H's Avatar
Jim_H
Banned
 
Joined: May 2001
Posts: 12,264
Likes: 3
From: The Great Northwest
Default

I made over 460 with a twin screw and have the dyno sheet to prove. Your sheets, however, are doctored



Originally Posted by all4woody
Beating a dead horse. Is the discussion that 460rwhp can't be made, or that it can't be made by a twin-screw? The Murph kit, which was one of my other choices, put down 463 with the same setup as mine.

Last edited by Jim_H; Jul 21, 2005 at 02:34 AM.
Reply
Old Jul 20, 2005 | 11:36 PM
  #75  
Sab's Avatar
Sab
Addict
Rennlist Member

 
Joined: Jan 2002
Posts: 1,732
Likes: 0
From: Florida
Default

edited...
...comparing two cars with equal PSI at same dyno should settle HP questions and creative math...

Last edited by Sab; Jul 21, 2005 at 05:33 PM.
Reply



All times are GMT -3. The time now is 09:17 AM.