[OpenFlash]

One thing we have been doing routinely is compression testing our single turbo test car to see how it is holding up to all this abuse/power level. For those who haven't been following from the start, this early build 2007 has been run hard from as early as 200 miles. It is, after all, our one and only in-house n54 development mule. So you can imagine that we started to pay a lot more attention to compression results since we started making 600+whp nearly 6000 miles ago. This morning, we pulled the factory plugs (which were installed 6000 miles ago) and replaced them with NGK 5992 plugs (single tip iridium):

The old plugs:


Old compared to new NGK plug:


Then we did the compression test:


And the results were pretty much perfect:

Cyl...PSI

First crank
1...120
2...120
3...122
4...120
5...119
6...120

7th crank
1...165
2...160
3...160
4...160
5...165
6...160

The only "issue" we noticed is that the valve cover gasket is leaking slightly in the spark plug hole for cyl 3. So if that is the ONLY thing we have to fix in a 88,000 mile heavily abused engine, we're happy

Cheers,
shiv

[themyst]

Welcome to my world lol.

Ps my car cranked 90-120 psi on a single crank regardless of which cylinder it was. When I cranked it a bit longer I'd see 135. Never cranked it over 7 times though.

You planning on replacing all the bolts with new ones or reusing?

[saxon]

What compression are these motors? And is it possible to do the tests with the tb open?

[OpenFlash]

Originally Posted by themyst

Welcome to my world lol.

Ps my car cranked 90-120 psi on a single crank regardless of which cylinder it was. When I cranked it a bit longer I'd see 135. Never cranked it over 7 times though.

You planning on replacing all the bolts with new ones or reusing?

The first crank psi is pretty important. Pressure should stop building after the 3rd or 4th crank. The last few cranks are just good measure.

I don't plan on doing the valve cover gasket anytime soon. The leak is tiny and not causing any issue. Will probably get around to it once we install the built motor.

[Q4P]

Shiv, are you ever going to discuss the fueling of these single turbo upgrades?

[OpenFlash]

Originally Posted by saxon

What compression are these motors? And is it possible to do the tests with the tb open?

Youd have to physically force the throttle open which we didn't do. No real need just as long as all the cylinders give similar results. All you need to do is unplug the injector connectors so fuel doesn't spray.

Compression ratio is rated at 10.2:1

[drfrink24]

Originally Posted by Q4P

Shiv, are you ever going to discuss the fueling of these single turbo upgrades?

+1

Itching to hear this. The fact that its been hush hush for this long leads me to believe its very easy and/or cheap to implement, so keeping it under wraps is pure business strategy (and rightly so).

[OpenFlash]

Originally Posted by Q4P

Shiv, are you ever going to discuss the fueling of these single turbo upgrades?

Nope. Not until we need to

Shiv

[Former_Boosted_IS]

Shiv, are you just testing the plugs or do you know they will work?

[Q4P]

Originally Posted by drfrink24

+1

Itching to hear this. The fact that its been hush hush for this long leads me to believe its very easy and/or cheap to implement, so keeping it under wraps is pure business strategy (and rightly so).

Or it's a lot different that people expect or not exactly what they expect...

[dAng! E90]

Originally Posted by Former_Boosted_IS

Shiv, are you just testing the plugs or do you know they will work?

Would like to know this also.

[themyst]

Originally Posted by dAng! E90

Would like to know this also.

Those NGK plugs have been used by a few RB turbo guys well before Shiv even mentioned it in this thread. They're one step colder than stock and will work perfectly fine.

Hell, it's a small miracle that the stock plugs hold up under the power of any legitimate turbo upgrade solution as it is. N54 = an overengineered marvel.

Now, if we could only get some larger injectors and a heavy duty HPFP....

[asuresh8]

wow 88k is really good for a valve cover gasket. Mine started leaking at 30k.

[themyst]

Originally Posted by lilballa

wow 88k is really good for a valve cover gasket. Mine started leaking at 30k.

hah, you too? I have the new gasket sitting in my kitchen... but it's a royal PITA to do so I'm procrastinating lol.

Mine was probably toasted before 30k since I pulled my plugs at 34k and saw oil on one of them.

[99three]

Very impressive compression numbers. A valve cover gasket issue after all the abuse is laughable. A great endorsement for the N54!

[Andrei@G35driver]

Originally Posted by shiv@vishnu

The only "issue" we noticed is that the valve cover gasket is leaking slightly in the spark plug hole for cyl 3. So if that is the ONLY thing we have to fix in a 88,000 mile heavily abused engine, we're happy

Cheers,
shiv

That is also leaking vacuum. It's possible that it is visible on a dyno chart as jitters.

[TwinTurboXI]

Notice any improvement with the new plugs? Does changing the plug alone adjust the gap?

fyi i'm still on my original valve cover gasket at 74,000 miles.

[jpsimon]

Originally Posted by lilballa

wow 88k is really good for a valve cover gasket. Mine started leaking at 30k.

I'm at 77k on the original valve cover gasket.

that being said i'm currently trying to figure out what seems to be a boost leak... probably a long shot and totally off but could a leaky valve cover gasket cause boost leak-type symptoms (not hitting boost target, with maxed wg duty cycle).

[Former_Boosted_IS]

Originally Posted by themyst

Those NGK plugs have been used by a few RB turbo guys well before Shiv even mentioned it in this thread. They're one step colder than stock and will work perfectly fine.

Hell, it's a small miracle that the stock plugs hold up under the power of any legitimate turbo upgrade solution as it is. N54 = an overengineered marvel.

Now, if we could only get some larger injectors and a heavy duty HPFP....

There have been now drawbacks whatsoever? No misfires?

[enrita]

Originally Posted by Former_Boosted_IS

There have been now drawbacks whatsoever? No misfires?

no missfires. i had these on for 4000 miles now with 2 track days, races etc.

[jpsimon]

Originally Posted by themyst

Those NGK plugs have been used by a few RB turbo guys well before Shiv even mentioned it in this thread. They're one step colder than stock and will work perfectly fine.

Hell, it's a small miracle that the stock plugs hold up under the power of any legitimate turbo upgrade solution as it is. N54 = an overengineered marvel.

Now, if we could only get some larger injectors and a heavy duty HPFP....

my car didn't like the NGK plugs for some reason back when i tried them over a year ago, i switched back to the stock plugs very quickly

[Tzu]

Originally Posted by themyst

Welcome to my world lol.

Ps my car cranked 90-120 psi on a single crank regardless of which cylinder it was. When I cranked it a bit longer I'd see 135. Never cranked it over 7 times though.

You planning on replacing all the bolts with new ones or reusing?

Stretch bolts. Replace em.