Welcome to the North American Subaru Impreza Owners Club Sunday September 21, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Engine Management & Tuning > Other Engine Management

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 11-21-2005, 02:17 PM   #1
jblaine
Scooby Guru
 
Member#: 8512
Join Date: Jul 2001
Chapter/Region: South East
Location: St. Pete, FL
Vehicle:
2002 WRX chassis...
stage-infinity.com

Default Hydra, plugs, engine noise

I've got a version 8 EJ207 shortblock + WRX heads and a 16G, as a lot of you know. As part of that swap, I had purchased heat range 7 *and* 8 NGK iridium plugs. The heat range 8 plugs were purchased as a backup based on two things:

1. NASIOC user ebeck had "lots of knock" with heat range 7 and had to use 8 on his EJ207 setup (much larger turbo, however).

2. The compression ratio of the v8 EJ207 block with WRX heads is somewhat unknown. Quirt at Crawford Performance has told ebeck several times that it is roughly 9:1. I have not convinced myself firsthand of this yet.

So here we go:

I'm running a Hydra Nemesis.

Over the last 5 months (it feels like a tedious 2 years), I have been datalogging the hell out of my car. Here's the cliff notes version in chronological order:

- Swap done, using heat range 7 NGK iridiums

- Original Element Tuning map was reporting lots of knock. This was a rough map done for a PE1820 turbo.

- Sunoco GT100, 16psi peak, and conservative timing did not make this reported knock go away.

- Insert skepticism and some fear

- After discussion with Phil @ Element Tuning, I used the 100 octane tankfull to generate a new Knock Threshold map to suit my car.

- A month or so after that, I revisited this. I was uneasy about the knock voltage levels (regardless of octane) that seemed distant from the other main cluster at that RPM and load.

- I contacted Phil again. This time I provided him with a plot of my unloaded free-revving knock voltage from 0-6500RPM. I also provided him with portions of logs containing WOT pulls. I also provided him with 5 knock voltage plots showing 2+3+4 pulls from 2800-6800RPM at WOT. Lots of data, all done with 100 octane, reasonable boost, and reasonable timing.

- Phil commented that, aside from his car, he had never seen knock voltages that high in his Hydra tuning. Perhaps the heads are noisy. Regardless, it was his assessment that it was extremely unlikely that it was knock given the data in the logs sent.

- For reference, my knock threshold map was above 2.05 volts from 2400 to redline. I would consistently see 2.1 and 2.2 voltages in spots above 5600RPM.

- Before doing a track day at Sebring, I decided to do a compression test now that the swap had 3000 miles on it (many many many WOT pulls while tuning, etc). Compression was 150psi in all cylinders. Heat range 7 iridiums looked fine.

- Changed oil, did the Sebring track day, changed oil, yadda yadda.

- Ever-paranoid and cautious, I was still not convinced everything was okay, I decided to try heat range 7 NGK copper plugs. No significant change in noise level.

- Yesterday morning I pulled the copper plugs after 2 weeks of use. They looked normal/boring.

- I installed the heat range 8 NGK iridiums finally. DRASTIC change in knock voltage levels. I have seen a single 1.9 out of 20 pulls, and that was at 6500RPM. From 0-5700RPM the voltages are well below 1.7, mostly below 1.2 even.

- I got another tank of Sunoco GT100 last night and started rebuilding my entire knock threshold curve (I am currently at $280 in GT100 fuel just for the sake of tuning a basic knock threshold curve).

- Keep in mind that I have never heard a single audible detonation event.

THE QUESTIONS

a) What the hell is going on here?

b) I don't really care about the answer to this one, but was ebeck's "knock" as reported by his UTEC not knock at all? I clearly ran my car hard for 3000 miles on 93 octane and 18psi with high knock voltages from my heat range 7 plugs. The result? Perfect compression still. Car runs like a champ. Super crisp.
jblaine 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
Hydra Standalone Engine Management 555ideways Engine/Power/Exhaust 4 10-29-2007 10:04 AM
Hydra Standalone Engine Management 555ideways NESIC Private Classifieds 3 09-22-2007 10:49 AM
Engine Noise - Cold Engine gkbrowne89 Normally Aspirated Powertrain 11 02-21-2006 12:24 PM
Scratching/Scraping noise in Cabin. Engine Noise? Help! seasons Factory 2.0L Turbo Powertrain 3 10-22-2005 06:34 PM
instant low oil, engine noise, drivetrain noise, help! emnm79 Factory 2.0L Turbo Powertrain 4 02-20-2005 09:20 AM


All times are GMT -4. The time now is 04:25 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.