Welcome to the North American Subaru Impreza Owners Club Wednesday September 20, 2017
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
Go Back   NASIOC > NASIOC Technical > Normally Aspirated Powertrain

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads. 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 03-04-2002, 04:11 PM   #1
Patrick Olsen
NASIOC Supporter
Member#: 120
Join Date: Jul 1999
Chapter/Region: AKIC
Location: Where the Navy sends me...
1997 Legacy 2.5GT
1996 Impreza coupe

Default Dyno graph comparison - stock SOHC vs. stock DOHC

A little while back a group of us NESIC types got together for a dyno day at Adrenalin Motorsports in Massachusetts. I dyno'd my '97 Legacy 2.5GT 5-speed sedan in stock configuration (well, stock + K&N drop-in filter and synthetic fluids), and Marc Sawaya dyno'd his '00 2.5RS 5-speed also in stock configuration.

We all know that the SOHC is supposed to have better mid-range than the DOHC, and I wanted to see how true that was. So, I finally got around to reading the numbers off of my graph and off of Marc's graph to create a combined DOHC vs. SOHC graph. I did actually cheat a bit on my graph - the day that Marc dyno'd his car (and hit 104.x hp) my car dyno'd at 100.6hp or something like that. On a previous day, also in stock configuration, and on the same dyno, I had dyno'd at 104.x hp. Knowing that (theoretically) the peak power should be the same on the two engines, I used my graph from an earlier day so that the graphs would "match". Who knows, maybe in real life the SOHC cars actually do make a few more HP than the DOHC engines, as was indicated on the day we dyno'd at the same time. Or, perhaps the few extra HP that Marc's car laid to the rollers was due to the fact that my engine has twice (?) the mileage and hence is a bit tired? I dunno. I just figured for a "neater" comparison I'd use the graphs that had virtually matching peak power outputs.

So, here's the graph:

It's pretty clear to see that the SOHC has significantly better mid-range torque. You can also see that, at least in this case with these specific engines, the DOHC doesn't drop off as severely at high RPM. (Plus we DOHC-kids can actually rev to redline! )

Pretty cool, eh?

Edit: I apologize for the light blue SOHC Torque curve, which is kinda hard to see - you'll have to thank Microsoft Excel for that!

Also, the dyno used for both cars was a Dyno Dynamics Low Boy AWD eddy current type dyno.

Pat Olsen
'97 Legacy 2.5GT sedan

Last edited by Patrick Olsen; 12-06-2006 at 01:23 PM.
Patrick Olsen is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
RS SOHC vs RS DOHC for hybrid swap Spilner Normally Aspirated with bolt-on Forced Induction Powertrain 25 08-15-2007 10:25 PM
Anyone have a dyno of a vf-34 vs stock? mrtrex Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 7 10-21-2005 05:22 PM
PDX In Texas Dyno Graph Comparison - Green vs. 20G SloRice Proven Power Bragging 22 10-20-2005 11:21 PM
STI Dyno graph comparison vf39 vs DB td06-20g Thanks to Harman Motive! mitchwrx Proven Power Bragging 10 09-22-2005 12:37 AM
Stock WRX vs Stock Touring 350z highflyerbballer Proven Power Bragging 26 12-08-2002 08:57 AM

All times are GMT -4. The time now is 03:38 PM.

Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2017 Axivo Inc.
Copyright ©1999 - 2017, North American Subaru Impreza Owners Club, Inc.