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

Cracked Flat Top Intake Manifold

Thread Tools
 
Search this Thread
 
Old 10-11-2015, 04:54 AM
  #1  
Junior Member
Thread Starter
iTrader: (1)
 
orlmiata's Avatar
 
Join Date: May 2013
Location: Orlando, Florida
Posts: 70
Total Cats: -7
Default Cracked Flat Top Intake Manifold

Hi Gents,

I have cracked my Flat Top Intake manifold on the corner closest to throttle body. I think I may have reversed the Hondata Teflon gasket. Regardless as soon as torqued it down to 18 ft-lbs, it cracked. You can see the pictures. Any suggestions on how to fix it?

Thanks.
Attached Thumbnails Cracked Flat Top Intake Manifold-image1.jpg   Cracked Flat Top Intake Manifold-image4.jpg   Cracked Flat Top Intake Manifold-image5.jpg   Cracked Flat Top Intake Manifold-image2.jpg  
orlmiata is offline  
Old 10-11-2015, 09:40 AM
  #2  
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Default

A welder
aidandj is offline  
Old 10-11-2015, 03:29 PM
  #3  
Elite Member
iTrader: (16)
 
99mx5's Avatar
 
Join Date: Oct 2006
Location: Las Cruces, NM
Posts: 1,647
Total Cats: 524
Default

How soft it that spacer? It looks deformed from compression. Looks like less torque is needed when using it.
Weld it up while bolted up to a flat plate, then check the flange for flatness.

Last edited by 99mx5; 10-11-2015 at 03:39 PM.
99mx5 is offline  
Old 10-11-2015, 03:37 PM
  #4  
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Default

Originally Posted by 99mx5
Are you using the intake manifold brace?

I was thinking what could cause that to happen.
- over-torqued bolts
- soft heat-isolation spacer
- no manifold brace
- combination of the above coupled with engine vibration
He cracked it torquing it down.

Bad torque wrench?
Something stuck underneath it?
aidandj is offline  
Old 10-11-2015, 03:41 PM
  #5  
Elite Member
iTrader: (16)
 
99mx5's Avatar
 
Join Date: Oct 2006
Location: Las Cruces, NM
Posts: 1,647
Total Cats: 524
Default

Yeah, I realized it then changed my post. You beat me to it.
99mx5 is offline  
Old 10-11-2015, 07:28 PM
  #6  
Junior Member
Thread Starter
iTrader: (1)
 
orlmiata's Avatar
 
Join Date: May 2013
Location: Orlando, Florida
Posts: 70
Total Cats: -7
Default

Originally Posted by aidandj
He cracked it torquing it down.

Bad torque wrench?
Something stuck underneath it?
I had definitely flipped the Hondata Teflon gasket. The additional support for the end that cracked, was on the opposite corner.
Attached Thumbnails Cracked Flat Top Intake Manifold-hondata.jpg  
orlmiata is offline  
Old 10-11-2015, 08:51 PM
  #7  
Former Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,099
Default

Why are you using one of those gaskets in the first place?
Savington is offline  
Old 10-11-2015, 09:03 PM
  #8  
Junior Member
Thread Starter
iTrader: (1)
 
orlmiata's Avatar
 
Join Date: May 2013
Location: Orlando, Florida
Posts: 70
Total Cats: -7
Default

Originally Posted by Savington
Why are you using one of those gaskets in the first place?
The believe is that it helps prevent heat transfer from the head to the intake manifold. How true or how much difference it makes, I am not sure.
orlmiata is offline  
Old 10-11-2015, 09:22 PM
  #9  
Junior Member
iTrader: (1)
 
leboeuf's Avatar
 
Join Date: May 2013
Location: Sandia Park, NM
Posts: 451
Total Cats: 50
Default

...
leboeuf is offline  
Old 10-11-2015, 09:52 PM
  #10  
Former Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,099
Default

Originally Posted by orlmiata
The believe is that it helps prevent heat transfer from the head to the intake manifold. How true or how much difference it makes, I am not sure.
Think about the airflow being ingested by the engine and the speed of that air. Heat transfer has a time component. How hot does the intake manifold really get? How long is the air actually in contact with the intake manifold? What percentage of the air actually picks up any appreciable amount of heat, and what percentage of the air ends up insulated from the intake manifold by the air around it?

Take your IM and a scrap cylinder head to a competent welder. Bolt it down and weld it back up, then throw that silly phenolic spacer away.
Savington is offline  
Old 10-12-2015, 09:07 AM
  #11  
Elite Member
iTrader: (17)
 
pdexta's Avatar
 
Join Date: Aug 2007
Location: Knoxville, TN
Posts: 2,949
Total Cats: 182
Default

I put one of those gaskets on my wife's RSX several years ago and tested the temps before and after. The gasket definitely makes a difference in IM temps and while that may not show significant gains I can't imagine it's hurting anything. Added bonus on a miata, it gives you another 1/4" or so of room to get your rerouted coolant return past your intake piping.

I don't know if they're worth running out to buy, but I certainly wouldn't throw it away if you already have one.

Hondata IMG temp variations
Not sure if anyone has done this before, but I figured I'd post up my results. I took some before and after temperature readings from the intake manifold to see how the gasket would affect manifold temps. All tests were done mid-day in south FL, similarly hot as hell for all 4 tests (2 before, 2 after) on a type S with only raceheader, no other mods. Along with the gasket I rerouted the coolant lines to the throttle-body as described in hondata's instructions with the gasket.

Temperatures were taken from 3 points that were marked on the manifold and taken with a infra-red temperature gun. Sample points are seen below:



Before temperatures:
Point 1: 157, 159
Point 2: 138, 140
Point 3: 137, 137

After temperatures:
Point 1: 144, 146
Point 2: 132, 133
Point 3: 131, 131

Temperatures close to the head were down 11-13 degrees. Farther away from the manifold temperatures are less drastic (as expected), 6-7 degrees. The test made me curious what kind of difference would be seen where the manifold mates to the head, I'd expect an even wider margin in the results there.
Attached Thumbnails Cracked Flat Top Intake Manifold-80-100_1986_1_f5d6042539e71bbe558bb9e6eeb6aa4cf14c117b.jpg  
pdexta is offline  
Old 10-12-2015, 11:13 AM
  #12  
Former Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,099
Default

Originally Posted by pdexta
I put one of those gaskets on my wife's RSX several years ago and tested the temps before and after. The gasket definitely makes a difference in IM temps and while that may not show significant gains I can't imagine it's hurting anything.
The temperature of the manifold is irrelevant. What matters is the temperature of the air entering the engine. The air entering the engine is traveling very quickly, and most of it never comes in contact with the intake manifold in the first place. Reducing the intake manifold's temperature will have virtually no effect on the temperature of the air entering the engine. The "gains", if any, would be virtually impossible to measure.

This thread is about a guy who cracked an ear off his $600 Squaretop while trying to install one of these gaskets, so I'm pretty sure he hurt something.
Savington is offline  
Old 10-12-2015, 12:03 PM
  #13  
Elite Member
iTrader: (17)
 
pdexta's Avatar
 
Join Date: Aug 2007
Location: Knoxville, TN
Posts: 2,949
Total Cats: 182
Default

Originally Posted by Savington
This thread is about a guy who cracked an ear off his $600 Squaretop while trying to install one of these gaskets, so I'm pretty sure he hurt something.
He installed it backwards, that's hardly the parts fault.
pdexta is offline  
Old 10-12-2015, 01:04 PM
  #14  
Supporting Vendor
iTrader: (3)
 
emilio700's Avatar
 
Join Date: May 2005
Posts: 7,325
Total Cats: 2,377
Default

Originally Posted by orlmiata
Hi Gents,

I have cracked my Flat Top Intake manifold on the corner closest to throttle body. I think I may have reversed the Hondata Teflon gasket. Regardless as soon as torqued it down to 18 ft-lbs, it cracked. You can see the pictures. Any suggestions on how to fix it?

Thanks.
Welder. Ditch the gasket. It took a long time for us to begin experiencing issues with the Hondata gaskets on our cars. We dropped them from our website when we did.
__________________


www.facebook.com/SuperMiata

949RACING.COM Home of the 6UL wheel

.31 SNR
emilio700 is offline  
Old 10-12-2015, 09:51 PM
  #15  
Elite Member
iTrader: (5)
 
Stealth97's Avatar
 
Join Date: Oct 2007
Location: Canton, Ga
Posts: 2,156
Total Cats: 66
Default

Originally Posted by Savington
The temperature of the manifold is irrelevant. What matters is the temperature of the air entering the engine. The air entering the engine is traveling very quickly, and most of it never comes in contact with the intake manifold in the first place. Reducing the intake manifold's temperature will have virtually no effect on the temperature of the air entering the engine. The "gains", if any, would be virtually impossible to measure.

This thread is about a guy who cracked an ear off his $600 Squaretop while trying to install one of these gaskets, so I'm pretty sure he hurt something.
I must respectfully disagree. I run a similar but thinner gasket, and the manifold stays cool to the touch. We sat 3 ice cubes on the manifold once, it was worth 3 hp on the dyno on a 90+ degree day.
Stealth97 is offline  
Old 10-12-2015, 10:13 PM
  #16  
VladiTuned
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 35,821
Total Cats: 3,481
Default

Originally Posted by Stealth97
I must respectfully disagree. I run a similar but thinner gasket, and the manifold stays cool to the touch. We sat 3 ice cubes on the manifold once, it was worth 3 hp on the dyno on a 90+ degree day.
Most will claim that 3hp can easily be the variance between 2 pulls, and they'd be right.

I'm sure you knew that and did multiple back to back testing to disprove this......................................right?
18psi is offline  
Old 10-13-2015, 12:17 PM
  #17  
Senior Member
 
AlwaysBroken's Avatar
 
Join Date: Jun 2015
Location: TAMPA, FL
Posts: 817
Total Cats: 20
Default

I've been running a squaretop with one of those gaskets for years now. Is this a reliability issue?

The manifold is off the head for now but I'm wondering if I should just omit it when I reassemble everything. Also, besides the reliability improvement (ie, the broken tb issue), are there any other real upsides to doing the skunk2 throttle on a squaretop and porting the intake to match?

I mean, if I'm running 18 psi of boost measured at the intake manifold, won't I just be reducing the pressure ratio further up the line (ie, less restriction for the compressor to push against to make that level of manifold pressure)?
AlwaysBroken is offline  
Old 10-13-2015, 12:22 PM
  #18  
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Default

If the throttle body is a restriction then yes it would help. Most people do it for reliability.
aidandj is offline  
Old 10-13-2015, 01:59 PM
  #19  
Elite Member
 
codrus's Avatar
 
Join Date: Mar 2007
Location: Santa Clara, CA
Posts: 5,165
Total Cats: 855
Default

AIUI, the throttle body's flow is not a major restriction for a turbo because you're compressing the air before it flows through it. It is a lot more significant on a positive displacement supercharger where you have to suck a larger volume of lower pressure air through it.

--Ian
codrus is offline  
Old 10-13-2015, 02:01 PM
  #20  
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Default

Still a restriction. Probably not an issue for the amount if air a Miata flows. But still a restriction.
aidandj is offline  


Quick Reply: Cracked Flat Top Intake Manifold



All times are GMT -4. The time now is 12:00 AM.