Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

 
 Reply to this topicStart new topic
> Turbo Boost Pressure / Comp Ratio, Useful data chart
Maltese Falcon
post Dec 7 2009, 08:50 PM
Post #1


Advanced Member
****

Group: Members
Posts: 4,645
Joined: 14-September 04
From: Mulholland SoCal
Member No.: 2,755
Region Association: None

I found this chart (from Holley/ Weiand) in my archives and it basically calculates your actual total C/R by adding boost pressure to your static C/R. So my biturbo is running 7.0 static and at 22 psi boost pressure the engine is running at 17.3:1 total c/r. I use 100 octane for anything over 16 psi.
Sorry for the print quality of the chart.
Marty

Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Sleepin
post Dec 7 2009, 09:08 PM
Post #2


Advanced Member
****

Group: Members
Posts: 3,647
Joined: 20-November 07
From: Grand Junction, Co.
Member No.: 8,357
Region Association: Rocky Mountains
So when I was running 14psi on my Honda engine with 11.5:1....wow...that is scary! (IMG:style_emoticons/default/biggrin.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Numbchux
post Dec 8 2009, 02:15 AM
Post #3


Newbie
*

Group: Members
Posts: 33
Joined: 3-September 09
From: Duluth, MN
Member No.: 10,758
Region Association: Upper MidWest
hehe cool, our rally car is running 17psi on 11:1. that's almost 24:1 effective

of course, we're running 102 octane.



my built subie motor is shooting for 6psi at 9.5:1 (IMG:style_emoticons/default/beerchug.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Zardozz
post Dec 9 2009, 12:21 PM
Post #4


Member
**

Group: Members
Posts: 107
Joined: 31-March 08
From: Orange County, CA
Member No.: 8,874
Region Association: None
So...

At 7.5:1 + 12# = 13.6:1 on pump gas with no audible detonation, not bad. I might have to try some 104oct and take it up to 16# just for fun.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
McMark
post Dec 9 2009, 12:50 PM
Post #5


914 Freak!
***************

Group: Retired Admin
Posts: 20,179
Joined: 13-March 03
From: Grand Rapids, MI
Member No.: 419
Region Association: None
QUOTE
I might have to try some 104oct and take it up to 16# just for fun.

You've got more balls than I do. That sentence sounds like a blown motor to me, but I'm probably just chicken. (IMG:style_emoticons/default/unsure.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
r_towle
post Dec 9 2009, 04:28 PM
Post #6


Custom Member
***************

Group: Members
Posts: 24,574
Joined: 9-January 03
From: Taxachusetts
Member No.: 124
Region Association: North East States
QUOTE(Maltese Falcon @ Dec 7 2009, 09:50 PM) *

I found this chart (from Holley/ Weiand) in my archives and it basically calculates your actual total C/R by adding boost pressure to your static C/R. So my biturbo is running 7.0 static and at 22 psi boost pressure the engine is running at 17.3:1 total c/r. I use 100 octane for anything over 16 psi.
Sorry for the print quality of the chart.
Marty

Attached Image


Thank you....now make the header again.
The one for a turbo...

Rich
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Maltese Falcon
post Dec 9 2009, 07:06 PM
Post #7


Advanced Member
****

Group: Members
Posts: 4,645
Joined: 14-September 04
From: Mulholland SoCal
Member No.: 2,755
Region Association: None
QUOTE
QUOTE
Attached Image
Thank you....now make the header again.
The one for a turbo...

Rich
Hi Rich, did you mean these headers ??
Marty
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
r_towle
post Dec 9 2009, 07:16 PM
Post #8


Custom Member
***************

Group: Members
Posts: 24,574
Joined: 9-January 03
From: Taxachusetts
Member No.: 124
Region Association: North East States
two many cylinders.

The old kit you made for the Djet turbo setup....
I want one.

Rich
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Maltese Falcon
post Dec 12 2009, 11:37 AM
Post #9


Advanced Member
****

Group: Members
Posts: 4,645
Joined: 14-September 04
From: Mulholland SoCal
Member No.: 2,755
Region Association: None
Rich, we just couldn't re-introduce THAT kit (IMG:style_emoticons/default/driving.gif)
Marty

Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
iamchappy
post Dec 12 2009, 11:53 AM
Post #10


It all happens so fast!
****

Group: Members
Posts: 4,893
Joined: 5-November 03
From: minnetonka, mn
Member No.: 1,315
Region Association: Upper MidWest
Looks like i must be running around 14....
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
« Next Oldest · 914World Garage · Next Newest »
 

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 

Display Mode: Standard · Switch to: Linear+ · Switch to: Outline

Track this topic · Email this topic · Print this topic · Subscribe to this forum

- Lo-Fi Version Time is now: 17th May 2024 - 07:31 PM
Invision Power Board v9.1.4 © 2024  IPS, Inc.
All rights reserved 914World.com © since 2002
914World.com is the fastest growing online 914 community!
We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ...