The Dan

Fight!

It really depends on so many things. Budget $1500 and you should be happy with the change you will get

Lol. Our good tuners charge accordingly though

Do you want him to come and pick up the car on a Sunday from your house also?

+1, put them in on caps 3 and 4 like the GTR does

Am I the only one who read his entire post? He did a wet test

Sounds like it might be a valve problem. You need to do a leak down test

Not that I know of. It's just water and boost. You can run vacuum hose to replace the boost but the water line will probably need to be braid or similar as it will need to go into the turbos directly

You need to bend the lines out of the way and have them loosely sitting under the drain area rather than bolted to the head. If you are worried about rubbing, put a slit down some fuel hose and cover the steel line where it touches. There is not a lot else you can do, that setup is designed for race applications and assumes you won't be using the standard crap back there

Drilling out the internal drains doesn't really do a lot unless you funnel the leading edge of the top side because half the hole is covered by the valve spring seat.

What does the cam manufacturer suggest?

The problem with doing that is you then rely solely on the lift pump to keep up with the feed pumps. That equals boom on a 1st-4th straight run

It depends on the cam and valve mate. Also anything making more HP should have tighter clearance. If you are getting them set, always set them on the medium side because when they hammer their seat they will close up slightly.

All great suggestions. Also have you got your boot properly ventilated?

Yep bore scope. We have one at the shop for just such occasions. It really is surprising how many people sell cars under false advertising. We can also tell if you have forged rods and ARP studs inside by looking up the sump plug hole

I didn't get much into rings sorry. A lot to be learned there. If anyone wants some literature on ring tech just shoot me an email and I'll send some stuff your way

Yeah if you have had the engine built and it's higher comp ratio, that will improve the normal results usually. You would only need to go up to 9.5:1 at most to see figures like that. Do you run standard head gasket or a spacer multi layer?

We use cranking speed fairly regularly when we suspect a dead engine. We don't use a tester though. All you do is unplug the CAS and crank it over. Listen to the note of each stroke. If you are down on one cylinder, you will hear it quite easily. Healthy engine will be: da da da da da da Unhealthy will be: da da DA da da da f**k!

There are a couple of different types of electronic tests. Pulse test and cranking speed test. The pulse test measures variations in manifold pressure I am fairly sure. The pulses will usually be off if the cylinder is down on compression. The cranking speed test is done by monitoring cranking speed. A cylinder with reduced compression will have less resistance and therefore the engine will crank faster on that part of the cycle. I am fairly sure it's like a timing light with a scope type rpm counter. I have used neither of these methods and have only ever heard about them. From what I was told, they are pretty accurate also. I don't know about the pulse test as measuring the cylinder on the intake stroke is not really going to be terribly accurate as most of the rings made for modern engines are torsional so they act differently on the downward stroke. I don't know enough about it to argue with someone about its accuracy though lol

A lot of people think that but in actual fact it's not the case. Once the gases passing the ring/ring gap reach supersonic speed, none more can pass no matter how much more pressure is added. Gasses reach supersonic at fairly low engine RPM

Unfortunately there is nothing that can be done for the tune. If only it were that simple. With a turbo that small, making the power he does, means adding timing will make it ping. Reducing timing to stop the pinging will add heat and making it rich will do stuff all. THIS TURBO IS TOO SMALL FOR TRACK APPLICATIONS. For a street car, not a problem. Probably the most responsive upgrade to the factory setup you can hope for. I spent a fair bit of time talking with CB on the phone and talking with his tuner (who is extremely switched on and has many track and drag cars under his belt) but the simple fact is that you cannot get the gas to flow out of a turbine housing that small and make as much power for extended periods. Not sure if it's been mentioned already but it's making 245rwkw so I am told All heat is going to gather at the entry to the scroll where the housing begins. It's warping the manifold and the turbo but only at the flange face. It doesn't warp the face of the manifold against the head. The ONLY way to stop it from warping is to reduce the power or change to a higher flowing turbine/housing combination

It doesn't mean it's not built. Forged engines can have lower static compression due to the forging being made from a different material than the factory piston. They can expand more when at temp so the piston to bore clearance is more than the factory cast piston when they are cold and even when they are hot. Just not as much. I would say get a second test done at a different place and compare the result. Definitely make sure the engine is up to temp before pulling it apart. Also get them to do a wet test and a leak down test. This will help you determine where the compression loss is occurring. You could have valve train losses rather than ring problems and no, that won't give you excessive blowby

We've got a Snap-On gauge and an ABW gauge. I'll give you $50 if you can show me 190psi on your engine on either one. *sub clause* as long as it is an unopened engine haha

Oh and I forgot to add that 50psi is nothing compared to the 1500-2000psi your combustion chamber sees at peak power and cylinder pressure. Engine A might have 2000psi whereas Engine B might have 1850-1950psi due to his lower static result. Both cars will make within 5-10 HP of one another and potentially live just as long as one another.

When you get a compression test, the results are taken statically. That is why you will hear a lot of people refer to them as static compression results. Three guys get a compression test done, Guy A has 165psi even on all 6, Guy B has 125psi on all 6 and Guy C has between 140-170psi on all 6. The engines for both A and B are healthy engines. C is a dud. What happens when a compression test is done is the engine is turned over by starter motor and is not being moved by its own power. This static result can give you an indication of how healthy an engine is but it does not give you any indication of what it will do when the engine is running. A hundred more things happen dynamically when the piston is in motion and under power of combustion. The rings will seal A LOT better and everything is moving MUCH faster so leak down past the rings is virtually no more than when it was standing still. The reason C is a dud is because one cylinder has 170 and another has 140. The variation is far too high so therefore you can determine the engine has a problem. If all results are even but low, it can be due to a number of things. Worn exhaust valve guide, carbon build up on valves or ports, lower tension on rings, piston to bore wear etc etc. It shows the engine is aging but still healthy because there is no variation. If its a worn exhaust valve guide, on a static comp test the valve will seat in a totally different position every time and your low results could be due to that. It doesn't mean the engine is going to explode. We have seen RB26's with 120psi on all 6 making 600hp at the wheels on 30psi boost and 2 years later.....still going strong. Still has 120psi on all 6. Of course we have to set some limits in our mind about how far is too far for a low result to become a bad result. For a straight 6 that's 8.5/9:1 comp ratio generally I use 120 as a lowest limit before telling someone the engine is had it. For an Rb20 that was the lower comp ratio you might accept 100-110 as a lowest result. Back on the worn guide thing, the valve will seal much better when in fast motion or if the spring is improved it could actually clear away any carbon or make itself a fresher seat. That is possibly why you saw a higher result when fitting your larger cams. Camshaft size won't effect static compression results unless the cause of your comp low result is due to valve train deficiencies.