New Turbo Kit in the works. - Page 9 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Prefabbed Turbo Kits A place to discuss prefabricated turbo kits on the market
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools
Old 09-28-2008, 11:52 PM   #161
Junior Member
iTrader: (1)
 
Join Date: Aug 2008
Posts: 373
Total Cats: 36
Default

Once again, ovalizing the primaries doesn't cause cracking. I don't know why you keep claiming that. Sure, if you crushed them over and over, in opposite planes, until it strain hardens and fatigues (note the implication of the word fatigue), then sure it will crack (brittle fracture). But fatigue doesn't occur when ovalizing.

When ovalizing you're barely scratching the surface of the 304's excellent elongation properties. That's why you never see cracking of a manifold's primaries in the ovalized area near the flange, even when they're really thin wall primaries made with tubing instead of heavy wall pipe.
JKav is offline   Reply With Quote
Old 09-29-2008, 12:38 AM   #162
Elite Member
iTrader: (15)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 8,797
Total Cats: 248
Default

Quote:
Originally Posted by JKav View Post
Once again, ovalizing the primaries doesn't cause cracking. I don't know why you keep claiming that. Sure, if you crushed them over and over, in opposite planes, until it strain hardens and fatigues (note the implication of the word fatigue), then sure it will crack (brittle fracture). But fatigue doesn't occur when ovalizing.

When ovalizing you're barely scratching the surface of the 304's excellent elongation properties. That's why you never see cracking of a manifold's primaries in the ovalized area near the flange, even when they're really thin wall primaries made with tubing instead of heavy wall pipe.
I dunno why he thinks we're ALL wrong and he's right. Goes against everything I've ever learned. Guess his manifold is exempt from Newton's first law of motion.
patsmx5 is offline   Reply With Quote
Old 09-29-2008, 03:24 AM   #163
Junior Member
Thread Starter
 
Join Date: Sep 2008
Posts: 79
Total Cats: 0
Default

Quote:
Originally Posted by JKav View Post
Once again, ovalizing the primaries doesn't cause cracking. I don't know why you keep claiming that. Sure, if you crushed them over and over, in opposite planes, until it strain hardens and fatigues (note the implication of the word fatigue), then sure it will crack (brittle fracture). But fatigue doesn't occur when ovalizing.

When ovalizing you're barely scratching the surface of the 304's excellent elongation properties. That's why you never see cracking of a manifold's primaries in the ovalized area near the flange, even when they're really thin wall primaries made with tubing instead of heavy wall pipe.
I never said it caused cracking or even that it would crack. I said its more likely to crack. And it is more likely to crack than if it was left the way it was originally formed. Plus there is no point in going through all the trouble if its not going to net any significant gain in power. Thats the issue at hand more than anything.

And as for Pat, All the information you need is here, port size, pipe x-sectional area. You know the volume of the CC and you could calculate the EGVs using the pressure and volume of the gases. Then figure out what the change from the circular x-sectional area to the ovalized one will be. Why dont you calculate it all out and show everyone how "right" you are? All of your posts are quite frankly pompous and unnecessary.
jc_rotor is offline   Reply With Quote
Old 09-29-2008, 09:11 AM   #164
Elite Member
iTrader: (15)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 8,797
Total Cats: 248
Default

Quote:
Originally Posted by jc_rotor View Post
I never said it caused cracking or even that it would crack. I said its more likely to crack. And it is more likely to crack than if it was left the way it was originally formed. Plus there is no point in going through all the trouble if its not going to net any significant gain in power. Thats the issue at hand more than anything.

And as for Pat, All the information you need is here, port size, pipe x-sectional area. You know the volume of the CC and you could calculate the EGVs using the pressure and volume of the gases. Then figure out what the change from the circular x-sectional area to the ovalized one will be. Why dont you calculate it all out and show everyone how "right" you are? All of your posts are quite frankly pompous and unnecessary.
Nope, I'm not the brilliant engineer going against common wisdom. I know a change in X section will cause losses. YOU"RE the one saying that it doesn't matter, your way's better, and the losses are insignificant. So why don't YOU prove you're right. Cause I've got the majority on my side. You're the underdog. Come on, this should be easy for you.
patsmx5 is offline   Reply With Quote
Old 09-29-2008, 11:49 AM   #165
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,040
Total Cats: 407
Default

assume, for a moment, that squishing down the pipes will not change the material properties or lead to cracks...

having an instant transition from the oval flange to the round pipe will create an instantaneous change in the velocity and pressure of the exhaust gas.

this causes the gas to curl up around the sharp corner at the outside of the flange and reverse flow direction for a short distance in that space. the turbulent gas region will affect the smoothness of the flow out of the port. it may even be so turbulent as to increase flow resistance in the tube as compared to a smaller tube. gas flowing against opposite-direction flow is going to encounter higher friction than against a solid pipe wall. at the very worst, the turbulent flow will impinge on the original port diameter and slow down the flow more.

And just to keep you smiling, here are some silly pictures.




(this one from your friends at honda.


You may be thinking "oh but the pressure will stay constant!" and you'd be wrong. a diameter change like that results in irrecoverable pressure loss.
y8s is offline   Reply With Quote
Old 09-29-2008, 12:31 PM   #166
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

jc,

a) as jkav points out - headers / manis don't crack at the ovalized primaries, and lots of them are ovalized. They more typically crack at the collector welds.

b) if they aren't likely to crack at the ovalized spot, then it's just a question of total resistance - your sharp transition flange + bigger primaries vs. ovalized, smaller primaries.

c) the above is easy to measure with a flow bench. Why don't you do it? If there's a chance the majoriy here is right, it's worth the time and effort to do so, don't you think?
JasonC SBB is offline   Reply With Quote
Old 09-29-2008, 01:01 PM   #167
Elite Member
iTrader: (9)
 
TurboTim's Avatar
 
Join Date: Jun 2006
Location: Chesterfield, NJ
Posts: 6,485
Total Cats: 248
Default

How about we let his fabricator build the manifold they want to build?
TurboTim is online now   Reply With Quote
Old 09-29-2008, 01:32 PM   #168
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,908
Total Cats: 1,793
Default

Quote:
Originally Posted by TurboTim View Post
How about we let his fabricator build the manifold they want to build?

Braineack is offline   Reply With Quote
Old 10-11-2008, 10:05 PM   #169
Junior Member
 
Join Date: Jul 2008
Location: Savannah-ish GA
Posts: 57
Total Cats: 1
Default

Quote:
Originally Posted by jc_rotor View Post
I will NOT be selling the kit myself or making any money off this.


funny this was actually in the first paragraph of the first post. at this rate noone will discredit this statement.
Archetype is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Need help - Stock Balancer and Fastforward overlay pulleys Frank_and_Beans Supercharger Discussion 13 09-12-2016 09:17 PM
LucaCarMods's Boosted Dutch Miata Build! LucaCarMods Build Threads 11 02-14-2016 07:13 AM
Koni 1150 Coilover Kit drumman83 Suspension, Brakes, Drivetrain 2 09-25-2015 08:03 PM
WTB 90-97 miata low profile headlight kit DonPlatt WTB 0 09-25-2015 03:57 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 04:40 PM.