Leak down testing...

[FATGTS-R]

Ok, I understand a leak down test is meant to be superior to a compression test in assessing an engines health.

I might be installing a/market ecu on my engine based on results from a leak down test.

From memory the results are stipulated as a percentage of leakage per cylinder, with the lower percentage the better?

Can somebody please tell me what percentages I should be looking at to decide whether I go ahead with the ecu or not?

e.g. 10% = great health, 20% = OK condition, 30% = engine will die very soon. etc etc etc.

BTW, engine in question is an RB20DET-R.

Thanks in advance guys,

Jayson.......

[awurth]

I'm lead to believe a leak down test is pressure drop/time. It should all be fairly close, don't know how close though.

With a compression test percentage of difference should be no greater than 10%, what i was told by a mechanic.

What is an RB20DET-R? I don't know the "R" bit!

[krawler]

"RB20DET-R in the GTS-R is reputedly good for 220hp, up from the 180hp of the GTS-X"

I'm guessing a fancy-pants motor in the import 31's?

[krawler]

In fact:

Nissan built 800 "evolution" GTS-Xs, called the GTS-R.  The GTS-R used the RB20DET-R motor, which was based on the cooking version, but had a larger T03 turbo, and a huge intercooler mounted across the nose.  Factory rated at 215hp, it is often said that a GTS-R produces much more, perhaps in the region of 280hp or so.  You can recognise a GTS-R by its twin intercooler ducts in the front valance, and the large rear spoiler (as above in the black car), which is badged "Nissan Motorsport International".

[FATGTS-R]

In reference to the above quote the GTS-Rs RB20det-R actually had a TO4E, not TO3. Also different cams and a gorgeous NISMO stainless tubular exhaust manifold.

And about the 280hp thing, its a bit hard to say if its true. When I put mine on the dyno it was stock standard and delivered 180hp @ wheels which would assume the 215hp @ fly is correct.... BUT mine was dynoed at 8psi and when they left the factory they pushed approx. 14psi. Would the extra 6psi from the TO4 push the flywheel power to the 280hp region?, I am the wrong person to ask.

Back on topic though, I understand that the results from the leak down test should be fairly close across all cylinders but what percentage reflects an engine in bad condition?

i.e If the average leakage across all 6 cylinders is 50% with no more than a 2% fluctuation then fair enough there is a small variance across the block which is good but the leakage is 50% which i assume is very very bad.

I need to know what leakage percentage should start the alarm beels ringing?

[EVL R33]

I had a leak down test done two weeks ago before we retuned the car.. I was told between 20 - 40% is average, anything near or over 40 is getting bad...

All 6 of mine were around 10 - 15%

[R31Nismoid]

In fact:

not everything you read on the net is correct.

i know where that info came from, and its not really accurate