That engine though. Where will it sit among the great 4cyl NA's?

[ZDan]

Originally Posted by ermax

This reminds me a lot of the AP1 vs AP2. Peek didn’t go up and redline dropped a little (because they stroked it for the extra displacement) which had people bitching but after driving both it was clear that the AP2 had the edge.

The FA24 is gonna be a WAY bigger change in the right direction compared to F22C, which was a disappointment for many...

FA24: 20% more displacement with bigger bore at same stroke. F22C: 10% more displacement with increased stroke, same bore.
FA24: peak power rpm unchanged. F22C: peak power rpm dropped 500rpm.
FA24: slightly higher redline. F22C: redline dropped 1000rpm ("only" 700rpm for rev limiter tho)

F22C was a big disappointment for me. Don't hate it, but it was an almost pointless exercise IMO. If I had one 1st thing I'd do is reflash for lower-rpm VTEC engagement and 8500 rev limit... They did make about 10rwhp more than the F20C (~205 vs. ~195), but are hampered by narrow 6000-8000 VTEC range and lack of usable rpm headroom above peak power rpm. The AP1/F20C and AP2/F22C cars put up similar acceleration numbers. FA24 is going to be significantly quicker/faster than FA20...

There look to be ZERO downsides to the FA24 vs. FA20. +23hp and ~20% more torque throughout the range. I *wish* Honda had taken the same approach with the F22C!

[Tcoat]

Originally Posted by ermax

For sure the FA20 is an absolute bitch to work on and that nightmare will continue with the FA24. The biggest issue with the FA20 was oil pressure and who really knows if the FA24 will continue that trend. There have been plenty of threads where people have come up with their own solutions by changing the pickup tube and drilling a hole here and there. The high compression pistons will limit bolt on FI options but the pistons could be swapped, possibly with the ones from the truck. Not being FI friendly doesn’t really cross it off the list as a great engine though.

I totally agree that the FA20 isn’t even in my top 10 greatest engines. But we aren’t talking about the FA20. Going off limited info and a “STATIC” best case low res and smoothed dyno it looks like the power band is much better. This reminds me a lot of the AP1 vs AP2. Peek didn’t go up and redline dropped a little (because they stroked it for the extra displacement) which had people bitching but after driving both it was clear that the AP2 had the edge.

All we can do right now is dream and I see nothing wrong with that. I see nothing wrong with getting hopes high over a static, overly smoothed dyno in optimal conditions at the crank vs another static, overly smoothed dyno in optimal conditions at the crank.

Thinking someone was arguing that the image on the dash was live data is either an extreme reading comprehension problem or flat out trolling. I’m going with trolling because I know Tcot isn’t a dummy but loves an argument.

Not trolling.
You have fixated on one point that I was trying to establish early on and disregarded everything I have said beyond that.

I will put it all in one spot:

1/ He was very clear that he felt that the graph was a real life number. He stated outright that it "was taken from the test mule". This is not accurate nor even remotely true. It is a laboratory formed number based upon a bench tested engine with many correction factors applied.

2/ It was his contention that the graph was a fully accurate indication of the engine abilities. I went into the fact that it is not dynamic as part of my attempt to clarify that what that gauge shows on the dash is not in fact what the car is actually doing. Even at the crank you will not see those numbers unless you meet the absolutely ideal conditions under which they were calculated. When driving the gauge follows the graph perfectly and that is nearly impossible. This is why I focused on the fact it is not dynamic and a false impression of the cars true performance. It is not my only point it is but part of the whole picture.

3/ In true paper racer form he insists on using only those two number to establish what the performance of the car will be. As pointed out many, many times by several people other than just myself there is far more involved. Something as simple as some more conservative gearing especially in the final drive could easily negate the 15% increase in power and torque. We have no idea what the rest of the specs are yet and it s possible (not probable but still possible) that the true performance of the car will be no better than the first gen. Yes there is some nice low end torque according to that pretty graph but how well does the overall car use that? Did they have to compromise something else to get it?

4/ His very thread title says "where will it sit?" but as soon as anybody tries to say anything other than oh it is perfect he throws some random bullshit into the ring to counter them. If the question was rhetorical and he has already determined from the HP and torque that it is THE greatest then why pose it? Everybody that says wait and see or tries to provide facts is somehow a "fool", "troll" or "not sane" in his eyes. Yes I like a good debate with facts, and data used to support a position but when these things are totally disregarded then it is no longer a debate and just turns into a brawl. He has repeatedly resorted to insults and name calling which right away tells me he doesn't have a real point to make and just hopes I will go away so he can find fellow believers to join him in his circle jerk. At this point I don't give a flying fuck what he or you think about what I have tried to get across in this thread but there have been over 5,000 views of this thread and if just one person walked away and said "that makes sense" then I am content.

[NoHaveMSG]

My mistake. I thought the rev limit was decreased.


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[bcj]

What chew talkin bout Willis?

[ZDan]

Originally Posted by Tcoat

...there is far more involved. Something as simple as some more conservative gearing especially in the final drive could easily negate the 15% increase in power and torque.

Taller gearing won't negate the 20% increase (average across revs) in torque and 11% increase in peak power. Just like getting 4.88 gears won't magic an FA20 better power/weight, neither will taller gears negate the FA24's increased power and torque. Even with 3.9:1 diff for the FA24, it will have more torque to the wheels from any speed in the same gear, and of course will have *much* better acceleration overall, as if they do gear it taller that just means you can keep it in a lower transmission gear at a higher speed vs. with 4.3.

I'm *guessing* they'll go with something like 5% to maybe 10% taller overall gearing, which would be equivalent to either 4.1 or 3.9 with existing transmission ratios. Although they might widen transmission ratios (kinda hope not).
ANYway, here's what torque to the wheels vs. speed should look like '22 with different ratios vs. '17:

[ZDan]

Originally Posted by bcj

What chew talkin bout Willis?
Attachment 195543

My ideal modern sports car would be something halfway between MX-5 and BRZ, a ~2500 lb. short-wheelbase fixed-roof cab-rearward 2-seater with a compact ~2.5 V4 making ~250ish hp. Yeah....

[Tcoat]

Originally Posted by ZDan

Taller gearing won't negate the 20% increase (average across revs) in torque and 11% increase in peak power. Just like getting 4.88 gears won't magic an FA20 better power/weight, neither will taller gears negate the FA24's increased power and torque. Even with 3.9:1 diff for the FA24, it will have more torque to the wheels from any speed in the same gear, and of course will have *much* better acceleration overall, as if they do gear it taller that just means you can keep it in a lower transmission gear at a higher speed vs. with 4.3.

I'm *guessing* they'll go with something like 5% to maybe 10% taller overall gearing, which would be equivalent to either 4.1 or 3.9 with existing transmission ratios. Although they might widen transmission ratios (kinda hope not).
ANYway, here's what torque to the wheels vs. speed should look like 22 with different ratios vs. 17:

Yep. Pretty much what would be expected. You however are basing your theoretical (although probably very close) numbers on far more factors than just the rated HP and torque and that is all I ever asked for.

[NoHaveMSG]

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[ZDan]

Originally Posted by Tcoat

Yep. Pretty much what would be expected. You however are basing your theoretical (although probably very close) numbers on far more factors than just the rated HP and torque and that is all I ever asked for.

Yeah, not gonna know for sure until we get one on a dyno... I'm *assuming* the curve shown in the dash graphic is accurate as far as the shape of the hp curve, based on the accuracy of the dash graphic in my car, where the torque dip is proudly displayed!

[Spuds]

I bet that there are going to be aftermarket solutions for the FA24 which add a bit of top end power but also a torque dip. And then torque dip will suddenly be cool.

[NoHaveMSG]

Originally Posted by Spuds

I bet that there are going to be aftermarket solutions for the FA24 which add a bit of top end power but also a torque dip. And then torque dip will suddenly be cool.

There is a “ chips and dip” joke in there somewhere.


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[Cephas]

Originally Posted by Tcoat

You are 6 pages late.

Or to put it another way, that's two votes for the monster Fiat!

[Tcoat]

Originally Posted by Cephas

Or to put it another way, that's two votes for the monster Fiat!

Three actually. There was another one in between!
Although it proves there is indeed a replacement for displacement.

[ermax]

Originally Posted by NoHaveMSG

I am on the same page as far as not knowing exactly what the new variant of the FA24 will bring and you add a lot of great points @ermax. I guess the real point I am trying to bring to light with the OP is that there are other things besides technical specs and dyno charts that make an engine great or not so great and my best example of that is the current engine.

I think beefing up the midrange and lowering the redline is a good direction as far as reducing the oil pressure issue but it really doesn't fix the problem. In the lifetime of our little FA20D and the updates it got, the DIT oil pump was never one of them and that is something I never understood. They updated rocker arm geometry so they knew that was a problem, they have to have known that we are on forums bitching about lack of oil pressure. Things like that contribute to my skepticism of the new engine.

I wasn’t suggesting lowering the redline was something they would do. The AP2 lowering the redline was my only reference to redlines. The FA24 is bored more to get the extra displacement so it has the same piston speeds but more valve surface so theoretically it could run a higher redline. If you follow threads about oil pressure on the FA20, larger pumps never solved the problem. The fixes came in the form of changing oil galleries. Boring some and even tapping in secondary lines. I wouldn’t be surprised if Subaru made some oiling improvements on the FA24 but time will tell. At least they added an oil cooler.

Oil pressure isn’t too much of an issue until the temps get high so maybe that is why Subaru never addressed it. It’s a popular track car but still probably represents a very small fraction of their user base.