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Cracked Flat Top Intake Manifold
8 Attachment(s)
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. |
A welder
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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. |
Originally Posted by 99mx5
(Post 1274159)
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 Bad torque wrench? Something stuck underneath it? |
Yeah, I realized it then changed my post. You beat me to it.
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Originally Posted by aidandj
(Post 1274160)
He cracked it torquing it down.
Bad torque wrench? Something stuck underneath it? |
Why are you using one of those gaskets in the first place?
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Originally Posted by Savington
(Post 1274209)
Why are you using one of those gaskets in the first place?
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...
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Originally Posted by orlmiata
(Post 1274210)
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.
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. |
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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: https://www.miataturbo.net/attachmen...ine=1444655265 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. |
Originally Posted by pdexta
(Post 1274280)
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.
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. :party: |
Originally Posted by Savington
(Post 1274308)
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. :party:
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Originally Posted by orlmiata
(Post 1274120)
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. |
Originally Posted by Savington
(Post 1274308)
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. :party: |
Originally Posted by Stealth97
(Post 1274553)
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.
I'm sure you knew that and did multiple back to back testing to disprove this......................................right? |
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)? |
If the throttle body is a restriction then yes it would help. Most people do it for reliability.
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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 |
Still a restriction. Probably not an issue for the amount if air a Miata flows. But still a restriction.
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Originally Posted by AlwaysBroken
(Post 1274717)
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)?
agreed with others though that it's more for safety than power |
Originally Posted by 18psi
(Post 1274847)
the more restrictions you remove the more easily you make the power, or make more power with less heat and pressure, should you want to
agreed with others though that it's more for safety than power |
like some of your posts
kekeke ilu |
Originally Posted by 18psi
(Post 1274851)
like all of your posts
kekeke ilu |
Originally Posted by aidandj
(Post 1274849)
Boost is a measure of restrictions. A turbo won't produce any boost if there are no restrictions. It will just blow a lot of hot air.
Boost is a measure of restriction VS airflow. It would save a lot of people installing tiny JDM cams into their turbo cars that are running 15psi but could be on 25, for example. Dann |
Originally Posted by nitrodann
(Post 1274872)
I am really surprised that this isnt covered by performance magazines or websites in articles.
Boost is a measure of restriction VS airflow. It would save a lot of people installing tiny JDM cams into their turbo cars that are running 15psi but could be on 25, for example. Dann |
To paraphrase Good to Great by Jim Collins, you gotta rinse your cottage cheese if you want to maximize performance.
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My thought was that reducing the resistance would mean more flow at a given psi (I'm assuming that flow deficiencies between the intake and the compressor outlet are compensated for by the compressor putting out more pressure to push past the resistance), which would put me beyond the surge line at a lower RPM. Which I'd like a lot.
I'm just not sure I see any obvious paths to significant gains in this area and pretty much every avenue of experimentation seems pricey. |
Intake manifold? Bigger piping? Different engine?
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I'm already running a flattop and a 99 head. My intake piping could be slightly improved, but not by a ton. It's got good bends and it only changes diameter at the intercooler and the throttle. I guess a bigger throttle, port matched to the intake would get air across the throttle a little quicker, but I'm not predicting anything amazing there.
Bigger engine- would work, but my precious dollas. Strokers are fucking expensive. Different engine entirely- would work but dollas. Swaps make strokers look frugal. Cams- less likelihood of gains than stroker or swap, but also less money. Also more effort to get this to work. I would be pretty happy if I could find a drop in intake cam that added a bunch of lift with nearly stock duration. Bigger piping- could work, but wouldn't this make the entire setup more laggy by forcing the turbo to fill up more volume before the intake manifold gets up to pressure? |
if you're asking what would be ideal, then yes super smooth and short piping with really gradual transitions from compressor outlet all the way to tb would be ideal. and then a well flowing IM that's a perfect compromise of plenum volume, runner length/id/shape/position, with cnc machined head with +1 or +2 valves, with a perfect exhaust mani, and a well breathing hotside, and a really smooth downpipe with minimal bends and huge id, and...and...and
bust most cars here don't have all that. and you're still working with a BP that won't hold a candle to more modern engines. So you find the line between "good setup" and "money pit" and call it good. *edit: just the fact that you keep saying "moe dollas" means you're about done |
For me, the miata has basically been a 15 year exercise in me going "that's cool but I can do it for cheaper" and then, just as I think I have triumphed over the laws of engineering and physics, the car breaks in some horrible new way and I learn a valuable lesson.
edit: Yeah, having a budget sucks, but wife said I can have xidas when I get the engine back together, so it's not all shitty. |
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