20 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH996 C2 3.6l vs X51 dyno
Leading reported evidence
Use injector harness
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
We ended up using the injector harness on the passenger side.
Leading evidence: 'Use injector harness' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check with don at ebs' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
With the X51, it first goes over 250 lb-ft at 4000 and doesn't drop below 250 until 5600-5800 (depending on run).
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
Humidity was 6% on the initial run and 30% on the run last week.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
20 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T113718Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Just dynoed the new X51 engine and here it is with the original dyno from with the stock motor from 3 years ago. Here are a couple notes:
1. The initial dyno was the stock motor well borken in with around 38K miles.
2. The X51 has all the latest upgarades: Larger IMS bearing, improved oiling systems, improved seals, etc.
3. When the X51 engine was installed, the ECU was flashed with the latest factory X51 DME.
4. The X51 dyno is with only 1500 miles. I was told that it only needs 1000 miles to break in. The motor is tight and feels tight at higher rpms (above 6K). By the way the power starts taping and getting jagged on the graph above 6200 rpms, it is still breaking in. We figure it needs another 1500 to 2500 miles to be fully broken in.
4. Similar conditions with by dyno runs: 90's for temps. Humidity was 6% on the initial run and 30% on the run last week.
5. The torque is actually significantly stronger on the X51 at anything above 2000 rpms and if you compare it to a stock 997.1 S (3.8l vs the 996 X51 3.6l), torque is actually stronger across the rev band.
My general impression of engine is the opposite of what I was expecting. Freer flowing heads, intake manifolds, exhaust manifolds and bigger cams should all add up to increased power at high rpms and lower performance down low. What is really noticeable is the performance down low. You can easily feel the extra torque at lower rpms. Between 3K and 5k the X51 has a completely different character than the regular 3.6l with a strong torquey push in your back that does not exist with the regular 3.6l. I am curious to see what it will do once it is fully broken in.
Why is the graph compressed. What is going on below 4500 rpm?
I need to re run my dyno pulls. On my 3.6 the HP measured at 299 but my TQ is way down at 236 on a DynoJet. Our curves look very similar but it seems like mine are skewed towards the higher end. IE mine are very weak from 3K to 5.5K but take off from 6-7.5K compared to yours.
Sorry, no AFR plot. I didn't have it on the baseline runs from 3 years ago and since there is nothing to tune, I didn't have them hook it up this time. We started off up higher due to heat soak. On a long run we tried from 2K, it would just nose off above 5500 rpms. I don't have any good data from any of my runs below 3500. What I can tell is with the regular 3.6l torque peaks and is fairly flat from 3900 to 4900. With the X51, it first goes over 250 lb-ft at 4000 and doesn't drop below 250 until 5600-5800 (depending on run). I had the same problem with heat soak when we did the baseline dyno 3 years ago with the old engine. I don't think the car likes to be stationary on a dyno with temperatures in the mid to high 90's. For some reason, just starting up higher seems to fix it. It would be nice if there was a FAQ about dynoing these cars. It also took a while to figure out where to hook up for a tach signal. We ended up using the injector harness on the passenger side.
I am going to do my first DE on the engine and limit it to 6000 rpms in a couple of weeks. If it feels more broken in, I plan to hit the dyno again in a month or 2 when it is a little cooler.
If power tapering off at higher RPMs and showing jaggies that ain't due to break in, more likely due to foamy oil.
Oil might be foaming at high rpms and this foamy oil being fed to zero-lash lifters and foamy oil causes some give in the zero-lash mechanism and valves don't follow cam lobe profile accurately and power drops off. If power drops off then comes back it suggests the foaming condition improves at lower rpm and then as rpms climb again the foaming returns.
What kind of oil you running? Are de-foaming pots in engine ok? All scavenge pumps working ok?
Sincerely,
Macster.
An X51 car is a much different animal vs a regular 3.6... they are like completely different cars down low, and up high in the RPM range. Driving an X51 back to back with a "normal" makes this feeling apparent!
Resurrecting this thread. Why is there a dip in hp at 6000 rpm for the X51? Aren't we already on cam after 3200 rpm? What happens at 6000 rpm in an x51? Thanks!
Check with Don at EBS. If you don't have an x51 already, it's a lot more expensive due to the core charge. 3.6 x51 is about $17,000 with a $4000 core; a 3.8 x51 is about $14,500 with a $7200 core.
