taimar manifolds
Discussion
whitewolf said:
...the manifolds retain more heat and will warp the heads... true or false??
False. Less transfer of heat energy to the engine compartment ambient air has two principal functions.
1. Increased intake air density means more power.
2. Increased exhaust temperatures mean higher velocities, which translates to more power.
3. An added benefit, is that all other under hood components are exposed to a less harsh environment, and have a longer potential life cycle.
There are a few decent coatings available.
Best,
B.
Just to add, it may not be relevant, but it might well be.
Maniflow state that for their mini exhausts, if the manifold is wrapped, the warranty is voided.
Seeing as they are regarded as one of the best manufacturers for exhausts for minis, I think they probably know what they're doing,
Maniflow state that for their mini exhausts, if the manifold is wrapped, the warranty is voided.
Seeing as they are regarded as one of the best manufacturers for exhausts for minis, I think they probably know what they're doing,
No i hadn't used the search in other areas... only classics.
After lookin more into it I've read that heat wrap can bring premature exhaust failure... cracking, rusting, fractures.
As for now Im just leaving them... but still considering wrapping the manifold bends (between head and where the manifolds join together) and from the 3-1 part to the middle box.. effectively leaving the welded areas exposed..
After lookin more into it I've read that heat wrap can bring premature exhaust failure... cracking, rusting, fractures.
As for now Im just leaving them... but still considering wrapping the manifold bends (between head and where the manifolds join together) and from the 3-1 part to the middle box.. effectively leaving the welded areas exposed..
Slow M said:
alse.
Less transfer of heat energy to the engine compartment ambient air has two principal functions.
1. Increased intake air density means more power.
2. Increased exhaust temperatures mean higher velocities, which translates to more power.
3. An added benefit, is that all other under hood components are exposed to a less harsh environment, and have a longer potential life cycle.
There are a few decent coatings available.
Best,
B.
Point 1, probably true in most naturally aspirated installations.Less transfer of heat energy to the engine compartment ambient air has two principal functions.
1. Increased intake air density means more power.
2. Increased exhaust temperatures mean higher velocities, which translates to more power.
3. An added benefit, is that all other under hood components are exposed to a less harsh environment, and have a longer potential life cycle.
There are a few decent coatings available.
Best,
B.
Point 2, not sure how this works. I would imagine a higher temperature in the manifold would present as a lower gas density and a higher average pressure. The exhaust gas pressure works in all directions not just towards the tailpipe.
Have you read about this somewhere? I had a chat with a coating supplier at the Autosport a few years ago and left not at all convinced there was any improvement to the overall mass flowrate, though granted it would give a lower manifold surface temperature (and therefore higher temperatures elsewhere down stream).
Colin.
As Colin said i agree. it would lower temps but for everything you alter there's an after effect. also i do agree that the exhaust gases work in every direction not just one (aiming towards the tail pipe/least resistance)
For now I've fitted and left them... I'll look into ideas at a later date before bodies fitted
For now I've fitted and left them... I'll look into ideas at a later date before bodies fitted
longone said:
Point 1, probably true in most naturally aspirated installations.
Point 2, not sure how this works. I would imagine a higher temperature in the manifold would present as a lower gas density and a higher average pressure. The exhaust gas pressure works in all directions not just towards the tailpipe.
Have you read about this somewhere? I had a chat with a coating supplier at the Autosport a few years ago and left not at all convinced there was any improvement to the overall mass flowrate, though granted it would give a lower manifold surface temperature (and therefore higher temperatures elsewhere down stream).
Colin.
Colin, on the first, even intercoolers that are in lower temp surroundings benefit from reduced under hood temps, but I know what you're getting at. Point 2, not sure how this works. I would imagine a higher temperature in the manifold would present as a lower gas density and a higher average pressure. The exhaust gas pressure works in all directions not just towards the tailpipe.
Have you read about this somewhere? I had a chat with a coating supplier at the Autosport a few years ago and left not at all convinced there was any improvement to the overall mass flowrate, though granted it would give a lower manifold surface temperature (and therefore higher temperatures elsewhere down stream).
Colin.
On the second, yes, I've read it somewhere, a while back, and it's something my elder brother has tried to explain to me as well. I'll try to do his efforts justice here.
As I understand it, you have to consider the inertial mass of the high velocity exhaust charge, and look at its scavenging effect when compared to a mass whose velocity slows continuously after the valve.
I'd ask him to explain it to me again, but I'm not prepared for the ancillary lectures on sonic choke, cam lobe design as it pertains to overlap, and port diameter as a factor of valve size. I'd surely make the mistake of not seeing how these effects are not negated by stepped header designs, only to be reminded that these are intended to alter harmonics and reduce reversion.
Best,
B.
Ok fair enough Bernard. I would suggest then the question could be reworked to: does any given exhaust manifold desgn always benefit from maintaining as high a gas temperature as possible? or put another way, is it possible to produce two different manifold designs for the same engine that will discharge similar mass flowrates but only at their design surface temperatures?
My guess is that if this is true it is only marginal and would require great emperical testing to realise the potential. I say this because I am unaware of any professional competition system using heat insulation techniques on manifolds other than to control under bonnet temperatures. Consequently, I assume the hydrodynamic perameters your brother refers to are dominant.
Colin.
My guess is that if this is true it is only marginal and would require great emperical testing to realise the potential. I say this because I am unaware of any professional competition system using heat insulation techniques on manifolds other than to control under bonnet temperatures. Consequently, I assume the hydrodynamic perameters your brother refers to are dominant.
Colin.
longone said:
Ok fair enough Bernard. I would suggest then the question could be reworked to: does any given exhaust manifold desgn always benefit from maintaining as high a gas temperature as possible? or put another way, is it possible to produce two different manifold designs for the same engine that will discharge similar mass flowrates but only at their design surface temperatures?
My guess is that if this is true it is only marginal and would require great emperical testing to realise the potential. I say this because I am unaware of any professional competition system using heat insulation techniques on manifolds other than to control under bonnet temperatures. Consequently, I assume the hydrodynamic perameters your brother refers to are dominant.
Colin.
Colin, My guess is that if this is true it is only marginal and would require great emperical testing to realise the potential. I say this because I am unaware of any professional competition system using heat insulation techniques on manifolds other than to control under bonnet temperatures. Consequently, I assume the hydrodynamic perameters your brother refers to are dominant.
Colin.
I agree. Most of the racing exhausts I have seen, or heard of recently, use Ti or Inconel, with the thinnest possible wall thickness. Clearly, if top teams are not concerned... Still, it's a nice bit of theory.
Best,
B.
Ah... yes standard tubular...
I don't like the way my offside seems very flowed and my nearside well... look bodged!!
Also the nearside were a ballache to fit and nip up.. as if they aren't spaced out correctly and bend around the starter...
where do I look for these manifolds as shown... never seen any before for the Essex. Or build my own... :/
I don't like the way my offside seems very flowed and my nearside well... look bodged!!
Also the nearside were a ballache to fit and nip up.. as if they aren't spaced out correctly and bend around the starter...
where do I look for these manifolds as shown... never seen any before for the Essex. Or build my own... :/
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