24 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHDisplacement-upgraded M96 (3.8L/4.0L) owners: city/traffic driving impressions?
Leading reported evidence
Fill with each
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
I buy gas and diesel in bulk, and have my own tanks filled with each.
Leading evidence: 'Fill with each' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Fill with each' (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 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
This allowed these components to be fitted without compromise.
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.
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
My driving style has changed since I got my car back from F6I.
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
We used the data collected from his engine while it was on the dyno to create these files, so no guesswork was executed.
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
Yes, I have been told many times that this feat could not be accomplished, so we used the crankcase with the smallest bore size in the M9X family, and made the largest cylinder in the world take it's place.
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.
24 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.
1 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
No difference in clutching, starting off from stop nor shifting smoothness.
I'm still wrestling through the 3.8L vs 4.0L (99mm vs 101mm bore) choice for my '02 C4 3.6L engine rebuild and I realized that, for all the glowing opinions about how much better they perform that have been shared here, I haven't seen anyone mention how they handle under city driving/stop-and-go traffic-type conditions. The answer will probably be different for those with track-oriented builds, so specifically for those of you with street-oriented builds and especially those paired with manuals: what's it like compared to your original engine? Does the extra power/torque make them more twitchy? More annoying on the clutch-work?
I encounter a LOT of stop-and-go and 10-30mph crawling driving to/from work in the DC area, so if 4.0Ls (even well-tuned/optimized ones) are worse than 3.8Ls in this respect it might affect my decision between the two sizes. Thanks!
2005 996 C4S newly reconstructed F6I 3.8 Stage 1. Acts exactly like a "normal" engine until you lean on the loud pedal. No difference in clutching, starting off from stop nor shifting smoothness.
From the F6I website about this engine:"
Put simply, a Stage 1 Flat 6 engine makes more power, doesn’t break and features 100% USA made upgrade/ performance components, coupled to hand-craftsmanship.
It is bigger, faster and stronger, doing everything in a gentlemanlike manner; until the throttle is stabbed.
"
I completely agree with the summary sentence.
When the throttle is "stabbed" the smiles grow wider... I haven't found any downside in daily driving.
2002 4S 4.0 Stage 2 here, and in my experience it is as wildbilly described... acts as it did before in stop and go from what I've noticed. Though for me gas mileage did suffer marginally in the city from what it was originally when the engine was the 3.6L.
Other than that, I do not believe there are any other downsides.
That's great, thanks to all of you!! Unless someone has more to add, a different experience, or wants to chime in about their non-FSI engine, please consider my original question answered!
While I have you and since
@rotorite
mentioned it, have all of you had similar experiences with your gas mileage: slightly decreased city mileage and [presumably] similar highway mileage to your original engines?
I swapped my blown 3.4 for a 997.1 3.8. love it but it's an expensive swap in a 996.1 cause pretty much impacted most of the electronics including ABS and instrument cluster.
We typically see an increase of highway MPG, and a decreased in around town MPG. The increase on the highway can be as much as 5 MPG, based on what your engine was when we started, and what it is after we've finished.
What plays into this most is driving style, driving style, and more driving style. I make no promises with MPG, and won't even answer a rough question about it, because the engine is not the determining factor. Sometimes I have people that only want to buy my engine for better fuel economy, but I don't accept the builds. There's no way to guarantee that the engine will do what they want, and they set a bar that is often unable to be attained.
If you own a Porsche for MPG, you own the wrong car. Buy a freaking Prius.
I�ve never once thought about or even tried to measure mileage in my 996 or 986.... too busy doing other stuff. I did figure put where I can reliably get ethanol free gas in TX though which gives me reason for road trips!
Today I had a Stage 1, 4.4L on the dyno that made 435HP. The crankcase used to be fitted to a 2.7 Base Boxster, and the heads used to be 3.6 castings from a 996.
it made this power with stock throttle body, stock plenum, and stock catalytic converters, with stock mufflers.. It is truly a Stage 1 daily driver..
It'll be interesting to see what the economy is on this one, as time goes on.
We got to 4.4 from 18 years of development. The combination has the largest M9X bore size in the world, coupled to the longest stroke.
The cams are my R51 cams that were based from 3.8 Carrera S cams, with added lift, and duration, and set up with split lobe centers.
This isn�t an engine that�s just �bolted together�.
Nothing inside of it can be bought off a shelf- not even the lengthened timing chains.
Here�s the original piston for the crankcase that is used for the R44 engine. This should give you an idea of the level of modification that has been accomplished.
Boy this is TRUE! My driving style has changed since I got my car back from F6I. Before I drove it like a little old lady going to church because I was afraid it was going to puke it's guts. If you have heard the noise it was making you would understand. Now I can't keep it below 3,500rpm(after properly warmed up of course) because I want to hear the "song". I'm sure this has negatively affected my gas mileage, but like I said above I Don't Care!
^^^This^^^ Totally "normal" as far as how the car acts, but... it's personality changes drastically between 3k and 5k rpm. I went from 3.4 > 3.8l Stage II with a M96 04... I put the IDP 82mm Plenum with the GT3 throttle body shortly after getting it back (2 or three months) performance overall feels very similar - maybe a little smoother power (but difficult to quantify) the big difference I noticed immediately was that my gas mileage improved from roughly 18/21mpg to 20/23 (averages).
Just to clarify for those who think that you just bolted on the GT3 TB and IPD plenum.... That didn't occur. We wrote a new tune and sent it to
@dporto
to be uploaded with a handheld tuning interface. This allowed these components to be fitted without compromise. Every action requires a reaction, else you end up with compromise. We used the data collected from his engine while it was on the dyno to create these files, so no guesswork was executed.
I buy gas and diesel in bulk, and have my own tanks filled with each. Its 20 minutes to the closest gas station, so I have to be able to self sustain. I have vehicles that get less than 2 MPG, and I don't care.
I think I understand...So the increased length of the chains a result of the increased deck height of the block? That�s more my question - how to get such a large bump in displacement with the standard deck heights and other limitations of the block, I was thinking that at some point, a custom block might be needed to increase the distance to the crank and get more space to accommodate the longer stroke and to maintain your designed rod ratio?
Separate question: what�s your thoughts on a pre-oil system? If supposedly most engine wear occurs on startup, I would think a pre-oil system would be installed in more cars that are modified and built than I see today.
Among other things.. People always think about a single item requiring a corrective modification, but that's never the case. With any R43 or R44 combination there's a ton of changes. The engine uses Chevy parts, Honda parts, Ford parts, and some Mercedes parts. It uses some parts from modern sport bikes, and that's where I rubbed part of the valve train from. From the valve covers inward, there's not many Porsche parts in this engine, which is one reason why it kicks ***.
How do you do it?? However you can. Everything is modified, and nothing is the same as it was. Of course, there's always a copycat competitor reading these posts, so I can't say anything else about anything regarding how this is done. This is very advanced level development, and application, with everything on the line for the future of my program. Making the engine big wasn't easy, but what was much harder was developing a combination that could work with all stock ancillaries for a Stage I application, and not have the RPM range compromised. This engine makes peak power at 7,100 RPM, which proves the concept of the combination, as an engine this large would not be expected to make peak power past 6,200 RPM.
Yes, I have been told many times that this feat could not be accomplished, so we used the crankcase with the smallest bore size in the M9X family, and made the largest cylinder in the world take it's place. So, 2.7 to 4.4L, peak power at 7,100 RPM, with 385Lb/Ft of torque that;'s flat from 3,000-6,500 RPM, and it does this with zero aftermarket parts on the outside of the en fine, and it still breathes through the factory air box.
In fitted one of these to the very first M9X that I built. It has benefits, but at the same time there's a lot more ways that you can spend the money better. Also, if you do not set it up "the harder way", there's a possibility that you can take away all the benefits it gives, and create more issues. I haven't fitted one of these since 2008, and don't intend to ever use one again.
Lest I leave the wrong impression^^^... Everything I've done (including oil changes) since getting the car back has been in consultation with Jake/Judd/FSI. This is the "unseen" support you get when to sign on to do an engine with FSI ! It's a "Hollistic" approach to engine building (I'm sure Jake loves this image! Yoga pants anyone?
)
Would be unbelievable if it came from anyone other than you. Quite impressive. I like the 7100rpm peak. I hate it when engines run out of steam at the top end. Even the 6800rpm peak for my M96 with the 7300rpm redline cuts close to annoying.
This is a source reference. Confirm exact model applicability in the original material.
