Jump to content
SAU Community

Recommended Posts

I have heard that reducing CR with a thicker gasket does not do as much good as it might seem. Apparently it interferes with the combustion chambers squish area, its sort of 2 steps forward one step back. The turbulence in the combustion chamber gets reduced because the piston no longer comes close enough to the squish area in the head, this effect somewhat offsets the lower CR (turbulence caused by the squish area is important for mixing the fuel and air to reduce detonation) It makes enough sense, exactly how important it is I don't know? It's worth a looking into anyway.

If you need a HKS gasket, I think Merli had one he was selling for a very reasonable price, around $500, think it was a 1.6mm which will drop CR to 8.6:1.

The japanese have been running 300+rwkw with these gaskets no probs, so I think they are good insurance if you are thinking of heading up around that hp. An 8.6:1 CR will definately be more boost friendly than the stock 9:1 - never hurts to have a bit of insurance, probably why the GTR runs 8.5:1 CR.

DennisRB30: What you said is correct and very important. There is a lot of R&D in the squish area of each (good) IC engine. While the thickness increase is not much, and the effect of turbulence isn't much either, it sort of is a step back at the same time. Look at the US Hondas- high CR and turbos, fast times, because of Honda's superior squish design. (Combustion chamber and pistons)

The best way to decrease compression would be via different piston crowns. The people in the piston manufacturing business are very knowledgeable in this area. Although not cheap.

For an application that isn't insane, the thicker gasket would suffice I believe. But the more boost, RPM and power that is involved, the more it would take its tole.

you can use the standard nissan head gasket if the block is O-Ringed. I like the idea of 9:1 CR as it means a good power curve and better off boost drivability. I spose if you have forged pistons and rods you can have high CR (or at least stock 9:1) and high boost 1.2bar +

Aahh amosite, sorry but I just gotta respond

*Never ending dramas with leaking water jackets!

I have not had that problem, what engines?

*They are a thing of the past and will stay there.

Shoot I did a 900 bhp engine with one last week, is that past enough for you?

*Do japs use them?

Don't know, I haven't asked the 127 million (based on the 2000 census) of them yet, might get around it next millenium.

*Do Yanks use them?

Do they ever! I was at Indianapolis Motorsport Week last year and there were over 1,000 engines there and almost all had copper head gaskets.

Like all things mechanical, there is a right place and a wrong place for most things. Don't knock it until you are sure you have explored all the facts.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • That ring thing is interesting how it's holding everything together 
    • Hey guys. I have a 400R on its way to Australia from Japan currently and have a few questions I’m hoping others may be able to help with.   Wondering if anyone here has had any luck getting the Sat nav unit to work in Australia!? Assuming the Stereo is as simple as a band expanded and tv won’t work?  Seeing as they’re based off a Q50 which is Aus delivered is there any way to link that system to the nav? Nav modules and head unit are different part numbers and appear slightly different at the rear with plug ins etc. can I put my xtrail sd card into the rv37 and will that convert the maps or update to Australian? Has anyone got any advice here?     also has anyone fitted the factory remote start and Security system once it’s landed in Australia? I put an enquirey to Nissan Japan in via a third party, and they suggested it needs a Nissan Japan dealers device to setup and couldn’t guarantee if one here could do it or not. They can supply and I can physically fit it but to setup I would need a dealers device. Any information here would be appreciated also. I’ve seen one here with it fitted already prior to leaving Japan at a dealer/inporter, so clearly passes compliance and works when fitted Japan and doesn’t need changing here.      also, does the tyre inflation sensors work here? Does anything change with them when the vehicle arrives? Where are they actually situated? I’ve read they have batteries and they need to changing at times and seems like resetting involves the nav system?    any help here would be appreciated and any other aust specific information to help would be great. Looking forward to see what the current generation skyline is like and eager to see how many of the gadgets can be utilised here.  Thanks in advance 
    • Do need to take it with a pinch of salt. One of the adapter failures, they clearly had setup issues with the flywheel.  One of the slipping ones I spoke to and it was pretty clear the throwout was riding, rather than fix, just swapped to a new clutch.    These clutches are being put in anything from 5k offroad 4x4 beaters, GR yaris, 500hp commodores to 1200hp barra monsters. Bound to be some issues in some of them when they are not a simple bolt in affair due to the changes in height.    There is a lot going on in this picture and unless I did the job myself no way to tell what really happened. 
    • I did this mod in 2019  You just have to modify the top bracket of the ABS/TC/Fuel Pump Control ECU so it sits more upright and closer to the back seat and run a good quality positive battery lead from the engine bay, the negative lead i just bolted down to the body in the boot.
    • Damn... Not the feedback I want to hear.
×
×
  • Create New...