Nissan Road Racing Forums

Go Back   Nissan Road Racing Forums > Engine > Naturally Aspirated

Reply
 
Thread Tools Display Modes
  #21  
Old 10-08-2013, 11:40 AM
gbeaty gbeaty is offline
Member
 
Join Date: Oct 2012
Posts: 58
Default

Quote:
Originally Posted by Sleepy_Steve View Post
So... word is still out on hitting MBT with SOHC pistons?
Pretty much. We might've been at MBT, but with the cam timing off it wasn't making good power.

Quote:
Originally Posted by Tower240sx View Post
I built 1 highish compression KA24DE, SOHC pistons and a 1.3 (i think) headgasket,

I had 248 cams in it and didn't use the JWT gears, I moved it 4 teeth (or whatever the math I did said was right)

I made 155 at the wheels on a big roller Dynojet. the car had ALL factory induction, factory manifold/header to a 2.5" muffler shop exhaust. Only issue I had was when I took it to the track on too hot of a range spark plugs...still ran fine until it ate thru the exhaust valve seat pocket on cylinder 4...
Is that with a cat? Factory mechanical fan? Power steering? If so those seem like great numbers. Do you happen to have a chart or run file for that dyno?

Thanks.
__________________
Flatout Racing
#23 Z32 Chumpcar

Last edited by gbeaty; 10-08-2013 at 11:49 AM..
Reply With Quote
  #22  
Old 10-08-2013, 03:36 PM
Tower240sx Tower240sx is offline
Resident Grouch
 
Join Date: Sep 2008
Location: SoCal
Posts: 1,591
Default

cat, yes, mechanical fan, no that setup had 2 electric fans hidden in a stock rad shroud.

I'll see if I can dig up the Dyno Sheets.
__________________
I am SKULLWORKS
Reply With Quote
  #23  
Old 10-10-2013, 08:49 PM
gbeaty gbeaty is offline
Member
 
Join Date: Oct 2012
Posts: 58
Default

Thanks.

I'm waiting for my friend to dyno on his stock setup, to see where MBT occurs on that. I've heard numbers as high as 33 degrees before, though on his 162whp dyno I bumped the base timing up a degree or two without any effect (meaning 26-27 degrees or total advance, vs. factory 25). We were being conservative as the wideband we were using was bad and was incorrectly telling us the car was lean. So I didn't push it any further than a base advance of 22.

If MBT on a stock setup is 33 degrees, an 11:1 setup will probably be around 28 or so. I don't think you can get that high without det. But if MBT is at 25 on stock compression, I'm pretty confident 11:1 will work just fine.
__________________
Flatout Racing
#23 Z32 Chumpcar
Reply With Quote
  #24  
Old 10-11-2013, 07:36 AM
Def Def is offline
Budget Baller to the Max
 
Join Date: Dec 2007
Location: Houston, TX
Posts: 11,876
Send a message via AIM to Def
Default

I'm betting MBT on a stock 9.5:1 KA is about 27-30 degrees. 11:1 setup is likely in the 21-24 range.

Then again, I've got more experience on MBT of FI setups... or more likely the knock limit of 93 octane fuel.
__________________
'18 Chevrolet Volt - Electric fun hatch for DD duty!


DefSport Koni Sleeve and Spring Perch Buy!!!
http://www.nissanroadracing.com/showthread.php?t=5902
Reply With Quote
  #25  
Old 10-11-2013, 08:59 PM
Wheelman Wheelman is offline
Member
 
Join Date: Mar 2010
Location: Kennewick WA.
Posts: 47
Default

The stock KA24DE timing maps I've got show MBT in the 40-43 range at high manifold vacuum (low load) and in the 27-30 range as Def guessed at low manifold vacuum (high load).
Timing in the maps I have is all in by 2000 rpm with most of the ramp between 1200 and 1600 and tapers by a few degrees between 4000 and 6000.
__________________
Wheelman (Ken Wheeler)
73 240Z, LT1, 5-Speed
92 240SX SE, KA24DE-T
Reply With Quote
  #26  
Old 10-12-2013, 09:43 AM
Def Def is offline
Budget Baller to the Max
 
Join Date: Dec 2007
Location: Houston, TX
Posts: 11,876
Send a message via AIM to Def
Default

Actually, a MAF setup will have the timing column change due to engine VE. So it probably puts in full timing by 2500-3000 rpm, then keeps it constant or even adds in a bit of timing towards redline. The VE drops off by a ton on a KA towards redline, so it'll be trailing down to lower load columns.
__________________
'18 Chevrolet Volt - Electric fun hatch for DD duty!


DefSport Koni Sleeve and Spring Perch Buy!!!
http://www.nissanroadracing.com/showthread.php?t=5902
Reply With Quote
Reply

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



Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
vBulletin Style by: kreativfantasy.com
www.nissanroadracing.com