Building TURBO system for YJ
- Thread starter MikeGyver
- Start date
Time for an upd8.
The baro sensor from a few posts back was put in and has been working great. It's giving me .1kpa resolution, which is equal to 35ft elevation, so it can actually be used as an altimeter. Here is a datalog of showing a mile of elevation change driving over Imogene Pass (13,114ft) from Telluride to Ouray. Notice that atmospheric pressure up there was only 63.4 kPa, while sea level is 101kPa.
A bit after this Colorado trip the head gasket squished out on a long sustained 12psi pull. There is no MLS (multi layer steel) head gasket available for this engine, just the composite felpro one which isn't great for boost. The high cylinder pressures will generate a force that acts in opposition to the head bolt clamping force, when the clamping force gets low enough the composite head gasket will just push out. To combat this, I got a set of ARP head studs for a 4.0L. These greatly increase the clamping force so this shouldn't happen again.
The Jeep also developed an exhaust leak about 2 months after installing a new $60 cast iron manifold from eBay. I though it was the manifold gasket but this is what it turned out to be...
This is the second cast iron manifold the turbo has killed so I think I'm going to make a manifold that integrates easily into the existing system. It will be made out of schedule 10 stainless pipe weld elbows and 1/2" thick laser cut stainless flanges.
A bit after this Colorado trip the head gasket squished out on a long sustained 12psi pull. There is no MLS (multi layer steel) head gasket available for this engine, just the composite felpro one which isn't great for boost. The high cylinder pressures will generate a force that acts in opposition to the head bolt clamping force, when the clamping force gets low enough the composite head gasket will just push out. To combat this, I got a set of ARP head studs for a 4.0L. These greatly increase the clamping force so this shouldn't happen again.
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I look forward to seeing this.
What's the reason for the clipped bolt holes on the top of the two outer flanges?
RockChucker
Well-Known Member
- Location
- Highland
My guess is it’s a Jeep thing? Seems like 4.0s are that way since the intake manifold and exhaust manifold hang from the same bolts.
- Location
- The Land Northward (Bountiful), Utah
Intake manifold shares the same bolts as the exhaust manifold.I look forward to seeing this.
What's the reason for the clipped bolt holes on the top of the two outer flanges?
- Location
- West Jordan
Could an MLS head gasket from a 4.0 be cut short and work? There has to be a better solution than a crappy gasket...
Yes, that's one thing I looked at. If this gasket dies I will buy one and take a die grinder to it. A couple of the holes have to be moved half a hole width over but it should work fine.