Get serious about VVT - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 11-09-2009, 09:11 PM   #1
Elite Member
Thread Starter
iTrader: (3)
 
AbeFM's Avatar
 
Join Date: Aug 2006
Location: San Diego, CA
Posts: 3,048
Total Cats: 8
Default Get serious about VVT

VVT tune, Tec 2 vs. Hydra in a CSP car, + E85 - MX-5 Miata Forum

I keep seeing stuff like that. A good VVT tune verses VVT at full retard (or advance). So?! It's almost meaningless. Example:

Take the Miata, extend the driveshaft and hang the motor over the front bumper. Wow, now it handles like ****. Then, take it and hang it off the back bumper, wow, it handles like ****. But put in an adjustable one, and look how well it handles.

No surprise. You're comparing the two worst cases to an adjustable one.

I want to see a plot with the VVT fixed somewhere sensible - you know, 0 advance OR retard. Not fixed at one end.

I'd much rather see "I picked up 5 ft-lbs in the low end and 3 hp on the top end over the "best compromise", than "I got 65 ft-lbs more in the low end than I did when I pulled three spark plugs and ran diesel"

C'mon people. Show me something worthwhile.
AbeFM is offline   Reply With Quote
Old 11-09-2009, 09:44 PM   #2
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

not worth the effort.
hustler is online now   Reply With Quote
Old 11-09-2009, 10:10 PM   #3
Senior Member
iTrader: (14)
 
Join Date: Jan 2007
Location: Murfreesboro,TN
Posts: 1,277
Total Cats: 53
Default

Quote:
Originally Posted by hustler View Post
not worth the effort.
Devil's advocate: Why not?
Midtenn is offline   Reply With Quote
Old 11-09-2009, 11:11 PM   #4
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default



purple line is 3 degrees retarded.

you can interpolate mentally based on advance, retard, and half way between, can't you?

or are you 3 degrees retarded?
y8s is offline   Reply With Quote
Old 11-09-2009, 11:38 PM   #5
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

You are 3-degrees retarded. How does your "dynamic" cam profile (at best) compare to my super-awesome 99 cam?
hustler is online now   Reply With Quote
Old 11-10-2009, 12:04 AM   #6
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

somewhat less duration, but i have more overlap except that I have less overlap too.
y8s is offline   Reply With Quote
Old 11-10-2009, 01:31 AM   #7
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

I thought the 01 intake cam had the same duration as the 99?
JasonC SBB is offline   Reply With Quote
Old 11-10-2009, 11:03 AM   #8
Elite Member
iTrader: (9)
 
Join Date: Aug 2006
Location: Concord, North Carolina
Posts: 4,173
Total Cats: 5
Default

Quote:
Originally Posted by hustler View Post
not worth the effort.
For a CSP car completely worth the effort to run one of those motors with working VVT.
miatamania is offline   Reply With Quote
Old 11-10-2009, 11:33 AM   #9
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

Miata MX5 camshaft specifications

randy claims slightly less, but not complete data. some day I will degree one and measure it.
y8s is offline   Reply With Quote
Old 11-10-2009, 02:53 PM   #10
Elite Member
Thread Starter
iTrader: (3)
 
AbeFM's Avatar
 
Join Date: Aug 2006
Location: San Diego, CA
Posts: 3,048
Total Cats: 8
Default

Quote:
Originally Posted by miatamania View Post
For a CSP car completely worth the effort to run one of those motors with working VVT.
Absolutely. With a turbo, even things like broken ring lands or a hole in the block can be compensated for with more boost. But NA you actually have to try to make power. And everywhere, for CSP.


Quote:
Originally Posted by JasonC SBB View Post
I thought the 01 intake cam had the same duration as the 99?
I thought it had more. I was pretty sure the VVT cam was a lot better than the 99. Ah, no, short duration, high lift. Seems like with better cams it'd be awesome. Interestingly, the earliest dyno runs FM did showed the '99 and the VVT car basically the same. :-)

The MSM is decent, though, on intake and exhaust. I think the VVT exhaust is better, too, than 99. There was a thread on m.net which listed it out pretty well.
AbeFM is offline   Reply With Quote
Old 11-10-2009, 02:53 PM   #11
Elite Member
Thread Starter
iTrader: (3)
 
AbeFM's Avatar
 
Join Date: Aug 2006
Location: San Diego, CA
Posts: 3,048
Total Cats: 8
Default

Quote:
Originally Posted by y8s View Post
Miata MX5 camshaft specifications

randy claims slightly less, but not complete data. some day I will degree one and measure it.
Yeah - the posts I read are all "When I measured it, I got something different"
AbeFM is offline   Reply With Quote
Old 11-10-2009, 06:37 PM   #12
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Interesting how from 4200 to 4800 RPM y8's dynos don't show a large difference in output no matter where the cam phase is. In the n/a motor retarded was hugely weaker - it needed overlap to get the VE from the exhaust scavenging. This effect is probably more pronounced with a proper header like the guy in the post.

y8s are you confident that the Hydra software hits the target cam phase? Did you datalog actual phase and confirm it was hitting its targets at around the time you did these dyno plots?
JasonC SBB is offline   Reply With Quote
Old 11-10-2009, 09:11 PM   #13
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

Hydra doesn't log the phase so I have no idea. I only know that full retard is full retard.


The adaptronic on the other hand....

(note this is an old map and the VVT isn't set up at all--the stock ECU is controlling VVT)
Attached Thumbnails
Get serious about VVT-vvt_adap.png  
y8s is offline   Reply With Quote
Old 11-11-2009, 02:15 PM   #14
Elite Member
Thread Starter
iTrader: (3)
 
AbeFM's Avatar
 
Join Date: Aug 2006
Location: San Diego, CA
Posts: 3,048
Total Cats: 8
Default

Matt:
Wow, yeah, that's pretty amazing. :-) Can you find a way to watch the cam with a timing light? Hmmm, guess not. An o-scope would tell you, but kinda a PITA for a quick test.

Quote:
Kieth Tanner says:

1999-00 intake
248 @ 0.003"
204 @ 0.050"
0.326" lift

MSM intake
248 @ 0.003"
(can't find my notes for 0.050", why not?)
0.349" lift

2001-05 intake (VVT)
263 @0.003"
208 @ 0.050"
0.370" lift


1999-05 exhaust
251 @ 0.003"
210 @ 0.050"
0.350"
(Will edit when more ex info gets posted)


Jason: Your PM's are full. Check the alternator thread, people are having issues with the light not turning off all the way, would like to hear your thoughts on it.

And that's very odd, about the midrange not caring about cam timing, you're right, I've seen those graphs but it never struck me.
AbeFM is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
15x10 - 15x11 6UL @ 949 Racing emilio700 Wheels and Tires 151 06-02-2017 03:36 PM
WTB MP62 (Hotside) (NB2) Rick02R WTB 3 01-03-2016 08:18 PM
MS3 or MSPNP Pro konmo MEGAsquirt 22 11-05-2015 03:32 PM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
2003 VVT Head/Valve Cover/Actuator/Coil Packs - Low Miles! - $250 StratoBlue1109 Miata parts for sale/trade 7 09-24-2015 04:50 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 08:37 PM.