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We are in process of getting bakelite inlet gaskets for RB20/25 and 26. This material prevents heat transfer from heads to inlet plenum. For RB26 added bonus of replacing the factory paper throttle body and inlet plenum gasket which are notorious for blowing out and getting air leaks. Up to now only option is after market gasket such as expensive Tomei metal ones which work fine but still transfer heat.

We have had the gaskets scanned and ready to make and will have in next week or so. We have already had made for VG30 300ZX. This is not a new invention as they are available on E Bay a while back for many engines in USA but not Skylines so we decided to do it. They will not be much more than factory ones depending on volume but way cheaper and better than Japanese aftermarket ones. 2 birds one rock deal.

Wondering what the interest would be. Remember average of 7 degrees increase or reduction in temp means 1% plus or minus in power.

PS If you have stock inlet gaskets and boost your GTR which is most then only a matter of time. Also never put strong solvent cleaners down throttle bodies as it can disolve the factory grey rubber type throttle body sealant and cause an air leak and idle will remain way too high.

Pic is of my VG30 DETT.

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There's an old (over 5 years) Autospeed article about these:

http://www.autospeed.com/cms/A_0401/article.html

And i started a rather short-lived thread about it:

http://www.skylinesaustralia.com/forums/sh...ead.php?t=56688

I'd be certainly interested to see how these perform when tested independantly.

bakelite hey? How does this stuff go in compression - is it going to deform, crack or deteorate over time being squashed between the head and the inlet manifold.

What sort of temperatures can it cope with.

What are the thermal properties - ie heat transfer rate through the material, (W/Deg_C/m)

It has been used for this purposeas wel as many other applications for years. I am not aware of any probs only benefits. A hole lot better than aper ones the GTR's have from factory.

The only question I have is that the inlet manifolds already have coolant water passages in them so the the heat will come from the coolant rather than the head casting . I'm always in favour of good gaskets that seal well , but the heat insulation would probably work better on non water heated manifolds such as the RB26's plenum section . My theory only , I'd reckon at high flow rates (revs/boost) the inlet air dosen't spend enough time in the manifold section to absorb much heat . I also think its desirable to have some heat in the inlet charge at idle and low engine speeds for fuel vaporisation meaning clean emissions and good fuel consumption .

Cheers A .

Yes and we found this on VG30 also. We also remove the throttle body heating on zeds for same reason. You could drill and tap and run external these water galleries although have not had a close look at it on RB26. It is accumulative if getting heated by coolant and combustion heat, removing or limiting one will help. Correct air would not spend much time passing through although at low speed road driving probably make more of a difference. Main point being it would help and better than factory gaskets which is a prob and way cheaper than Tomei or other gaskets.

There is no benefit in heating the inlet charge unless you live in VERY cold climate and much more benefit in cooling or rather avoiding heating.

They will prob be around $50 each at most. Prob is I have to get at least a hundred made and adds up to thousands and will take a long time to sell a hundred or more to need to get some funds back.

being in the electricity industry I see allot of Bakelite products and when it is fairly thin, as it would need to be with a gasket, it would be fairly fragile and as with a paper gasket with some age it becomes brittle. wouldn't the ambient temperature of the engine bay sort of rule out trying to stop heat transfer by using the gasket to stop metal to metal contact. in a GTR the first intake manifold has a gallery fed from the the head in it which feeds both cooloant supplies for the turbo's, one around the front of the motor and one around the back. The throttle bodies and intake plenum don't have any water galleries in them. but your not wrong about the gasket blowing out between the head and the first intake manifold, my 33 did it straight away and i just spent a day replacing the one on my wifes 32.

Will advise when available and should be in next few weeks. Re temps the thing that makes the heat is the engine and turbo and this is what we are helping shield against. The heads are hotter than under bonnet temps.

  • 2 years later...

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