R&D thread for shim-under-bucket conversion! - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


General Miata Chat A place to talk about anything Miata

Reply
 
 
 
LinkBack Thread Tools
Old 02-12-2008, 02:57 PM   #21
y8s
2 Props,3 Dildos,& 1 Cat
Thread Starter
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

oh herro: $30 lash caps. Are these the ones you got from the weight lifter company? haha

http://cgi.ebay.com/ebaymotors/NEW-B...2em118Q2el1247
y8s is offline   Reply With Quote
Old 02-12-2008, 04:28 PM   #22
Elite Member
iTrader: (7)
 
samnavy's Avatar
 
Join Date: Apr 2006
Location: VIRGINIA BEACH, VA
Posts: 6,020
Total Cats: 175
Default

So, longer duration/lift allows more air through the head? I thought the limitation of the head was the actual layout of the air passages (small) and not the size/volume of the valves.

In the end, how much more RPM are we talking about here? The number for the stock valvetrain seems to be 7200 as an upper limit. To be worth anything, I'd think you'd want to see a 500-800rpm improvement. So, would converting to shim/bucket let you get up to the 8000rpm range... 8500?

I hesitate to think what the next limitation is. Turbo flow? Pump gears? Bottom end?

This mod isn't for me, but I'm still trying to figure out what the end-result in performance will be. Will it make more power? Will it rev quicker? If so, then how much... and where will you see the gains... and will the wear-and-tear on other components be worth it?
samnavy is offline   Reply With Quote
Old 02-12-2008, 04:41 PM   #23
y8s
2 Props,3 Dildos,& 1 Cat
Thread Starter
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

Quote:
Originally Posted by samnavy View Post
The number for the stock valvetrain seems to be 7200 as an upper limit.
That's my redline stock... I think people safely run 7500-7800 on the stock guts. Maybe that's later cars. minus the MSM.

the stress on the bottom end goes up exponentially with RPM so yes, that may very well be the limitation. I think with a full top to bottom motor build, running 8k isn't out of the question. Hell, I'll try it.

Lets see... all flow related items that need more flow with higher RPM become limiting factors: injectors, turbo, pumps can cavitate, harmonic damper, etc.

but the benefits are (if you keep your torque up) linear increase in hp as revs increase. Think S2000. Look at the power go up above 7000 rpm... yet torque is constant.

y8s is offline   Reply With Quote
Old 02-12-2008, 04:43 PM   #24
Elite Member
iTrader: (13)
 
cjernigan's Avatar
 
Join Date: Oct 2006
Location: Atlanta, GA
Posts: 8,147
Total Cats: 6
Default

Over 300 HP at 7.5 psi wowza. Wish we were so fortunate.
cjernigan is offline   Reply With Quote
Old 02-12-2008, 04:49 PM   #25
y8s
2 Props,3 Dildos,& 1 Cat
Thread Starter
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

couldn't be the .2 or .4 more litres...
y8s is offline   Reply With Quote
Old 02-12-2008, 04:49 PM   #26
Elite Member
iTrader: (5)
 
m2cupcar's Avatar
 
Join Date: Jan 2005
Location: Atlanta
Posts: 7,236
Total Cats: 288
Default

I don't know the specs on the springs we used with our cams but they were noticeably less stiff just by squeezing. Ideally you want less spring rate for a lighter valve train since you're moving less mass. I'm paraphrasing the engine builder, but the spring rate needs to be stiff enough for a good return on the valve (quick action) with minimal force against the lobe at compression. That said, we weren't revving past 7500. Our cams were geared more for torque and not high rpm power. So rev limit would also play into spring rate to avoid float. My guess is that's the point behind upgrading the springs on the stock valve train - to keep those giant shims from shooting out.
m2cupcar is offline   Reply With Quote
Old 02-12-2008, 05:02 PM   #27
Elite Member
iTrader: (5)
 
Join Date: Oct 2007
Location: Canton, Ga
Posts: 1,707
Total Cats: 19
Default

FYI I have a built engine with basically stock '99 valvetrain, and I occasionally spin it to 8k, I have great power at 7k but power really starts to drop off around 7200 or so, and by 8k my hp and tq are just about non-existent... I think its due to valve float.
Stealth97 is offline   Reply With Quote
Old 02-12-2008, 05:02 PM   #28
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

i think it's your cams
Ben is offline   Reply With Quote
Old 02-12-2008, 05:04 PM   #29
Elite Member
iTrader: (5)
 
Join Date: Oct 2007
Location: Canton, Ga
Posts: 1,707
Total Cats: 19
Default

could be either or both. Have not seen too many N/A 8krpm dyno pulls, but yeah, Jerry seems to think the stock cams are really holding me back... I agree.
Stealth97 is offline   Reply With Quote
Old 02-12-2008, 05:08 PM   #30
Elite Member
iTrader: (15)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 8,796
Total Cats: 247
Default

Quote:
Originally Posted by Ben View Post
i think it's your cams
+1. the faster you spin the motor, the less time the valve is open and it needs to draw in the same amount of air. Cams are what's killing it most likely, I doubt it's floating valves.
patsmx5 is offline   Reply With Quote
Old 02-12-2008, 05:12 PM   #31
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

Quote:
Originally Posted by Stealth97 View Post
could be either or both. Have not seen too many N/A 8krpm dyno pulls, but yeah, Jerry seems to think the stock cams are really holding me back... I agree.
valve float will feel more like a misfire
Ben is offline   Reply With Quote
Old 02-12-2008, 05:17 PM   #32
Elite Member
iTrader: (5)
 
Join Date: Oct 2007
Location: Canton, Ga
Posts: 1,707
Total Cats: 19
Default

Quote:
Originally Posted by Ben View Post
valve float will feel more like a misfire
Got to be the cams then. I need to pimp my valvetrain.. someone buy my NX kit
Stealth97 is offline   Reply With Quote
Old 02-12-2008, 05:30 PM   #33
y8s
2 Props,3 Dildos,& 1 Cat
Thread Starter
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

cam grind group buy!! heh.
y8s is offline   Reply With Quote
Old 02-14-2008, 03:39 PM   #34
y8s
2 Props,3 Dildos,& 1 Cat
Thread Starter
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

SO I found a couple things:

1. Manley makes 6mm lash caps that run for 30-45 for a whole set depending on where you get them (flatlander, summit, jegs).

2. the FM valve springs are the exact same rates listed on the supertech website. belfab has the set for roughly the same price.

3. Actually with a little looking around, Import Performance Parts/Flatlander has the valves and springs significantly cheaper than other places.

hmm.
y8s is offline   Reply With Quote
Old 02-14-2008, 11:36 PM   #35
Elite Member
iTrader: (12)
 
Join Date: Aug 2006
Location: Central-ish VA
Posts: 4,449
Total Cats: 16
Default

Quote:
Originally Posted by y8s View Post
oh herro: $30 lash caps. Are these the ones you got from the weight lifter company? haha

http://cgi.ebay.com/ebaymotors/NEW-B...2em118Q2el1247
Those are indeed the ones
neogenesis2004 is offline   Reply With Quote
Old 02-14-2008, 11:42 PM   #36
y8s
2 Props,3 Dildos,& 1 Cat
Thread Starter
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

Quote:
Originally Posted by neogenesis2004 View Post
Those are indeed the ones
kinda creepy, i'll probably go with flatlander and just get the whole valvetrain setup.
y8s is offline   Reply With Quote
Old 02-14-2008, 11:59 PM   #37
Senior Member
iTrader: (8)
 
Join Date: Mar 2006
Location: Floriduh
Posts: 882
Total Cats: 0
Default

I'd like to find a place that can sell just the Ti retainers and locks.
soflarick is offline   Reply With Quote
Old 02-15-2008, 12:30 AM   #38
Elite Member
iTrader: (12)
 
Join Date: Aug 2006
Location: Central-ish VA
Posts: 4,449
Total Cats: 16
Default

The retainers are made specifically for the springs. The super tech springs require their springs seats and retainers for out cars. My super tech springs were actually shorter than the stock springs. The winding wasn't as tight though, so they could still support more lift.

I would definitely get the entire valve train in a kit Matt. Those are the shims I am using though. I probably have 40hrs invested in grinding them myself with the knife sharpener though. I couldn't find a place locally that would grind them for me. Most places thought I was crazy to even ask.
neogenesis2004 is offline   Reply With Quote
Old 02-15-2008, 12:42 AM   #39
y8s
2 Props,3 Dildos,& 1 Cat
Thread Starter
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

or i can just order the supertech pre-sized ones...$4ea is much less than I'd charge myself in labor.
y8s is offline   Reply With Quote
Old 02-15-2008, 12:49 AM   #40
Elite Member
iTrader: (12)
 
Join Date: Aug 2006
Location: Central-ish VA
Posts: 4,449
Total Cats: 16
Default

You'll have to order them very last so that you can measure needed clearances.
neogenesis2004 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
Going back to stock. Need some 1.6 parts. Trent WTB 2 10-01-2015 01:15 PM
Leaky Wilwoods mx592 Suspension, Brakes, Drivetrain 1 10-01-2015 01:45 AM


Thread Tools

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 03:44 AM.