P-40

[cardboard_killer]

I hate to admit it but I am spoiled by the BoBp planes now. And I doubt I have more than 60 minutes in any of them, but when, for the first time, I got into the P-40, taxied it down and took off in it, I felt like I was driving a model T. And the P-39, which I liked a bit, made me sigh after flying in the P-38. Really, these were the planes that the US beat the axis with, but they . . . I cannot say it. Sigh. Biggest sigh.

[Eicio]

Well, the p40 was a little "overmatched" from the beginning, in game you'll struggle against any fighter if you don't have the energy advantage but still, it's a more than decent asset when it comes to ground support.

 

The p39 is a magnificent aircraft, any critics about it will be denied, so say we all.

 

45 minutes ago, cardboard_killer said:

Really, these were the planes that the US beat the axis with, but they . . . I cannot say it. Sigh. Biggest sigh

 

You overlooked two major points, IMHO, numbers and experience. I don't know the exact numbers but I wouldn't be surprised if you'd say that in the late war the axis-allied ration planes would be something like 1:30.

As for experience the attrition rate germans  suffered was pretty harsh, whereas the allies had more and more experienced pilots.

 

In conclusion 30 little p40 piloted by veterans would probably score a couple me 262 flawn by kids hands down and any day.

[Voyager]

Well, the P-40 was also really a interwar plane that had been up-engined and up-armed to keep some semblance of pace with the war, but it's basic design is a 1934 aircraft. 

 

I'm not sure what the issue is you're having with the P-39, aside from its engine, which did pretty much hobble it in US service, and is very twitchy in game. I think the P-38 was the only successful high performance Allison engines fighter, and it was also the only one that was able to mount the turbos. 

[CountZero]

Engine Fantasy timers ?

Edited March 27, 2020 by CountZero

[357th_KW]

3 hours ago, cardboard_killer said:

Really, these were the planes that the US beat the axis with, but they . . . I cannot say it. Sigh. Biggest sigh.

Really, they weren’t.  The US used a small number of P-39s mainly in the ground attack role in the MTO in late 42 and 43.  P-40s were used in larger numbers in the MTO, but they were using later F (Merlin) and K (Allison) models.  The premier US air superiority fighters in the MTO were the P-38 and Spitfire (lend lease Vc’s, VIII’s, and IX’s) in 42 and 43.  In late 43 and spring of 44, P-47s and P-51s came on the scene.  The Mediterranean was always an under equipped backwater for the Luftwaffe, and Allied forces enjoyed a significant numerical advantage from Torch in late 1942 (when the US involvement really dialed up) onward.

 

P-39s and P-40s never saw any combat in the ETO.

P-40s scored about 590 kills and P-39s around 30 in the MTO.  Counting both ETO and MTO the P-51, P-47 and P-38 had scores of around 5000, 3000, and 2000 respectively.

 

RAF and Commonwealth forces employed P-40E’s in the Western Desert in late 41 onward.  They generally were outclassed by the 109’s they faced, but the Luftwaffe didn’t have many 109’s to spare, and a P-40 definitely beats a Stuka, Ju88 or Ju52.

 

[cardboard_killer]

3 hours ago, KW_1979 said:

P-39s and P-40s never saw any combat in the ETO.

 

I dig all that, but I would counter it with this: the LW was effectively defeated in the MTO and ETO in 1943. They were used in the ETO and in decent numbers, just not by the WAllies. 

 

Edited March 28, 2020 by cardboard_killer
spelling

[gimpy117]

personally i think a lot of it is to do with it's engine timers, can't possibly hope to play with 109's with it's glass motor. seems to bleed speed very fast too, especially when careless with the rudder...which kinda makes me wonder. I never seem to have success with it but, I think the physiology update might have helped a little bit to level the playing field since 109's can no longer pull crazy g's to stay on your tail and draw lead with it's uncanny instantaneous AoA abilities. what will really help this aircraft and many Russian aircraft in general will be fixing spotting and visibility in general, invisible 109's will stop showing up out of nowhere. there are a few reasons for this, and i'm sure German aircraft to a certain extent are hampered too, but the nature of many German aircraft being ambush energy fighters lends itself extremely well to a situation where functional invisibility is a real reality. This problem is further compounded by the fact that many players have found a way to cheese the graphics of this game and (although I'm unsure exactly how but I assume large screens and low display resolution) can see you far easier than than you can in return. better spotting will help P-40 and many Russian aircraft, although outmatched, be able to take evasive or strategic action far sooner than currently.   

Edited March 28, 2020 by gimpy117

[Bremspropeller]

I think the 40 is flying fine.

It just won't climb (inherent to the airplane) and it has a glass-engine.

 

The 39 has that awful canopy-frame right in your face. And it has the glass-engine.

Other than that, it also flies very nice.

[smink1701]

The worst thing about the P 40 is cockpit textures. Abysmal IMHO. Many others are either great or amazing but this one needs to be reworked. The perspective is all wrong and looks elongated! Desperately needs to be fixed but I am not holding my breath. 

 

[ROTER_BART]

 

[LFL-EightyPLUS]

From what i remember,

The P40 supplied in-game was a hand-down from the USAF, since it was already build in great numbers but considered to heavy to counter either german or japanese fighters.

I never understood who the Devs chooce to model this version of the P40...especially since it was apparently not likes by any airforce who fielded it.. Moreover, its only real use is very much similar to an Il-2.... except its engine management is super sensitive....

[Zirashi]

21 hours ago, KW_1979 said:

P-39s [...] never saw any combat in the ETO.

 

Fun fact
 

Top 5 Allied aces of WW2 and the aircraft they scored the majority of their kills in:

 

Ivan Kozhedub - La-5/La-7

Alexander Pokryshkin - P-39

Grigory Rechkalov - P-39

Nikolai Gulayev - P-39

Kirill Yevstigneyev - La-5/La-7

 

[Avimimus]

22 hours ago, KW_1979 said:

Really, they weren’t.

[...]

P-39s and P-40s never saw any combat in the ETO.

 

Most air combat was on the EETO (Eastern European Theatre of Operations)...

 

Zirashi is right that most of the legacies of these planes are in the east (and to a lesser extent in the south)... and that is where most of the mid-war fighting happened... just because they weren't American pilots does not mean that it didn't happen (or that American built aircraft didn't have an impact).

 

As for the OP: Yes, going back to a LaGG after flying a latewar aircraft feels sluggish... the power and speed is a bit addictive... but it is mainly psychological...Perhaps fly a bunch of quick missions in the I-16 or Ju-52 to cleanse your palate and then try the P-39/P-40?

 

[LukeFF]

10 hours ago, smink1701 said:

The worst thing about the P 40 is cockpit textures. Abysmal IMHO. Many others are either great or amazing but this one needs to be reworked. The perspective is all wrong and looks elongated! Desperately needs to be fixed but I am not holding my breath. 

 

Abysmal? What on earth are you talking about? Go look at any cockpit photos of real P-40s, and it looks much the same.

 

6 hours ago, LFL-EightyPLUS said:

From what i remember,

The P40 supplied in-game was a hand-down from the USAF, since it was already build in great numbers but considered to heavy to counter either german or japanese fighters.

 

It's the export model of the P-40 E originally made to British specs, and the USAF didn't exist at the time.  Moreover, plenty of P-40Es saw action in North Africa.

Edited March 29, 2020 by LukeFF

[MAJ_stug41]

P40 in this game is competative with 109e7 and f2, beyond that it has no advantages. IRL the russians would run these allison engines indefinitely at rpm and ata that this game limits to 5 minutes or less. If the magical engine timer werent a limitation, it would be more fun, but it is difficult to incentivize players to fly at cruise engine settings since nothing simulates wear and logistics.

 

The thing that made the p40 great IRL was the fact that it was available to fight, and reliable, so it fought everywhere first half of the war and had a very high sortie rate. Another thing that cant be simulated here.

 

Lastly, p39 and 40 had good radios, which russian planes often lacked early on, but that cant be represented either.

 

 

It exists in an unfortunate nexus of game mechanics that leave it at a great disadvantage, but it is still a favorite of mine.

 

Shameless plug of my reverence for the p40 -

 

 

 

Edited March 29, 2020 by 2./JG51_stug41

[gimpy117]

35 minutes ago, 2./JG51_stug41 said:

P40 in this game is competative with 109e7 and f2, beyond that it has no advantages. IRL the Russians would run these allison engines indefinitely at rpm and ata that this game limits to 5 minutes or less. If the magical engine timer wasn't a limitation, it would be more fun, but it is difficult to incentivze players to fly at cruise engine settings since nothing simulates wear and logistics.

 

I can do nothing but agree, the engine times seem to be too restrictive on the Alison from what I have heard, British running them flat out with no problems other than lower TBO on the engine, and soviets doing very much the same. AFAIK the only reason why it was limited so in pre-war documents was to reduce engine wear.You cant even run the engine hard enough to tax the cooling system right now, which seems suspect. with the current performance of the aircraft i cannot see any real reason to not ease the limits on the P-40 and P-39 for a time. if the plane becomes over performing in a K:D standpoint, then, by all means put it back to where it was...buy why oh why not at least try and see.    

[Dakpilot]

The P-40 E-1 we have in game fits in historically in late Moscow and early in Stalingrad campaign .

 

No matter how much paople want it, it is not one of the later models which had better performance. 

 

The P-39 we have has similar "issues" 

 

The tactic used by Soviet pilots of flying at max continuous all the time even when in cruise, (to negate it's massive weight penalty transitioning to combat) does not pay off in game as everyone already does it (this - max continuous at cruise - was not a standard procedure) 

 

Cheers, Dakpilot 

[=621=Samikatz]

The P-39 is excellent in this sim. Take away the wing guns and you have a plane with fantastic roll, dive, and high speed pitch authority, that's also fast enough to catch the 1943 109s at sea level. On the offensive there's little anyone can do to truly evade your grasp

[jollyjack]

As for the P40 in IL2 i don't like it, every time i took it on a dogfight spin i crashes into the ground LoL. Th P39 is great, thanks for th no-wing guns tip, i'll try that ...

 

[BlitzPig_EL]

Try the 4 gun setup in the P40.  Still has plenty of punch, and longer time on the trigger, while lowering overall weight.

 

The key to the P40 is having some patience, starting high, and not jumping into a fight at the first chance.  It's a rugged airframe with a good roll rate, can actually turn pretty well, hampered only by it's gamey engine limits, and it dives really well too.  Choose your fight, not theirs.

 

A usable 50" of manifold would really change things for the Warhawk.

[Burdokva]

11 hours ago, Dakpilot said:

The tactic used by Soviet pilots of flying at max continuous all the time even when in cruise, (to negate it's massive weight penalty transitioning to combat) does not pay off in game as everyone already does it (this - max continuous at cruise - was not a standard procedure) 

 

Cheers, Dakpilot 

 

This!

 

I recently read through a fantastic series of interviews with Soviet fighter pilots (I believe they were recently published in Russian as "Они дралисъ на истребилях"), particularly noting the interview with Nikolay Golodnikov -  here . He flew on the Hurricane, P-40 and P-39, and has great insight into their use, and generally on fighter combat. I particularly recommend to everyone to read this and his comments on the difference between maximum, flat out speed, and combat speed envelopes - he makes it quite clear why some machines that had far lower flat out speed in tests can fight on equal terms with faster planes (to the horror on many in online communities).

 

I'll translate some of his comments:

 

- How would you rate the speed, climb, acceleration and maneuverability of the P-40? Did you find it satisfying?

 

- I repeat, the P-40 was significantly superior to both the Hurricane and I-16, magnitudes superior. Speaking personally, I could fight all types of Messerschmidts in the P-40 on equal terms almost up to the end of 1943. If you took the entirety of performance figures, the P-40 "Tomahawk" was equal to the Me-109F (sic), while the "Kittyhawk" was better. Speeds, vertical and horizontal maneuverability in it were better, comparable to the enemy airplanes. In terms of acceleration and dynamics, the P-40 was quite heavy but once you get used to the engine, they were completely normal.

 

When the later Me-109G and FW-190 types appeared, the P-40 "Kittyhawk" became inferior but not by much. And experienced pilot could fight in it on equal terms. I fought 10 - 12 aerial combats in it, in total I made about 50 combat sorties. After that, the regiment was reequipped with the P-39 "Aircobra".

 

- [Presenting a negative Allied combat report on the P-40 and Hurricane compared to the Bf 109F in the MTO from 1942]? Do you agree with this assessment of the fighter? 

 

- Yes, I learned back during the war that the Allies did not consider the P-40 a viable fighter for air combat. And we used the P-40 as a very decent fighter. When we used it, we found two great flaws that decreased its capability as a fighter. One, the P-40 was slow to accelerate - it gained speed very slowly. Poor acceleration and, consequently, poor combat speed. Second, it was poor it the vertical, particularly the "Tomahawk".

Both were the result of poor power-to-weight ration. We solved it in a simple manner. The first, kept the engine RPM higher, flying at higher speeds. Second, we lightened the plane by removing two machine guns. That's it. The fighter became decent. Yet, it all depended on you - do not "dawdle" with the throttle level, work with it fast. Yes, we should mention that the engines, in our "unintended" mode, ran for up to 50 hours - that was the limit, and usually less. On average an engine would run for up to 35 hours and then it would be replaced.

 

I believe the greatest difference in the rating of the P-40 between us and the Allies comes from the very different way we operated it. They flew it strictly per the instruction manuals. For us, as I said above, the number one rule was - squeeze out max performance of a plane, and then some. And how much that would be, it's not written in the instruction manual, usually even the aircraft designer does not know. You can only find out in combat.

 

In fact, everything said is valid for the "Aircobra" too. If we had flown it in the combat regimes stated in the American manuals, they [the Germans] would have shot us down immediately, in it's "native" regimes the fighter was "nothing". And on "our" regimes, we could normally fighter either the Messer [sic], the Fokker [sic] but, just 3 to 4 such air combat, and again - an engine change.

 

Sadly, we can't simulate logistics. If we could, at least in career mode, that would lead to interesting scenarios - do you flat out your engines but risk having no operational fighters in a few weeks, or conserve them to prolong operational life at the cost of poorer flight performance?

 

[gimpy117]

yet another reason why i think the devs should at least try a engine timer change. 

[Voyager]

From the recent dev diaries, it sounds as though engine damage may be the next big thing on the table after the structural damage model rework gets finished. 

[gimpy117]

8 hours ago, Voyager said:

From the recent dev diaries, it sounds as though engine damage may be the next big thing on the table after the structural damage model rework gets finished. 

but is that from a standpoint of limits or battle damage? 

[BlitzPig_EL]

Limits in all likelihood will never be changed. Sadly.

They are in place to force a more "realistic" play style on the user base, even though in real life the so called "limits" were tossed out the window if it meant saving pilot's lives. Engines can be rebuilt or exchanged a whole lot easier than a pilot can. Plus, the engines most hurt by this, the Allison V1710 and Pratt & Whitney R2800 were amazingly robust power plants that could be, and were, run way beyond "the book" and just kept going.

 

Be sure.

Edited March 30, 2020 by BlitzPig_EL

[Voyager]

2 hours ago, BlitzPig_EL said:

Limits in all likelihood will never be changed. Sadly.

They are in place to force a more "realistic" play style on the user base, even though in real life the so called "limits" were tossed out the window if it meant saving pilot's lives. Engines can be rebuilt or exchanged a whole lot easier than a pilot can. Plus, the engines most hurt by this, the Allison V1710 and Pratt & Whitney R2800 were amazingly robust power plants that could be, and were, run way beyond "the book" and just kept going.

 

Be sure.

 

At some point they will need to change them. The limits they set were per the pilot's handbooks. That worked well enough for the German and Russian fighters, and honestly, the P-40, because of it's completely manual engine controls that allow you to wildly over boost the engine required some sort of limits, but as they have moved into the Western front you are ending up with serious issues because the lay war LW, RAF and USAAF all had radically different ideas of what constituted an acceptable margin of safety.

 

In a set of extreme examples, the late war R-2800, which was producing ludicrously higher amounts of power that the pre-war versions still had exactly the same engine limits, while the P-38 Allison engines had instructions that were just plain wrong and damaging to the engine. By contrast, the DB605's, with minimal modifications were given revised manuals that ran the engines for many multiples longer than their previous production, with no real relevant changes that would justify turning a 5m time limit into a 1h time limit. Meanwhile the RAF was giving instructions to run engines for longer than the aircraft had fuel to use. 

 

And then you run into bizzare results, like with the P-47, where if you turn on Water injection set the RPM to the cruise setting, you can run the engine indefinitely at the 15m timer limit, even after the water has completely run out. Also reducing the inlet temperature reduces the time to failure, so apparently the way to run the engine is to back off the RPMs, and run the inlet temps in the detonation zone, turn on an empty water tank and go to town. I've mostly stopped flying it, because in a real engine, that's about the best way to get severe detonation going, and I do not want the negative training. 

 

At the same time, jamming 56" into an early war Allison that was never built for it, without any ADI or sufficient charge cooling is going to do some damage. Later Allisons were built for higher horsepower, but the one in the P-40 we have, as I recall, was not. 

[Dakpilot]

7 hours ago, Voyager said:

 

At the same time, jamming 56" into an early war Allison that was never built for it, without any ADI or sufficient charge cooling is going to do some damage. Later Allisons were built for higher horsepower, but the one in the P-40 we have, as I recall, was not. 

 

This

 

There were many important changes from the 1941 V1710 versions compared to later ones,  wanting ours to perform like a 1943 version seems to be just wishful thinking. 

 

If we had a P-40 N as well, a lot of people would be happier 

 

People also all seem to forget that the P-40 E-1 weighs empty more than a Bf109 G6 (without the 109's extra horsepower) 

 

Think about that rationally for a bit,

 

the P-40 E-1 is just not really a front line fighter any more in 1942, still an awesome aircraft which has its uses

 

Stay safe everyone

 

Cheers, Dakpilot 

[Avimimus]

On 3/29/2020 at 2:40 PM, Burdokva said:

Sadly, we can't simulate logistics. If we could, at least in career mode, that would lead to interesting scenarios - do you flat out your engines but risk having no operational fighters in a few weeks, or conserve them to prolong operational life at the cost of poorer flight performance?

 

If we ever get a Lisunov Li-2 we could expand that gameplay further... having to fly in with a replacement Allison strapped under each wing...

[=621=Samikatz]

I imagine things will improve when engine damage gets a bit more complicated and there are more states engined can be in. I don't think timers will go away, but having the consequence of them being managable failures rather than engines just straight up dying would be a big improvement

[-=PHX=-SuperEtendard]

2 hours ago, Dakpilot said:

 

This

 

There were many important changes from the 1941 V1710 versions compared to later ones,  wanting ours to perform like a 1943 version seems to be just wishful thinking. 

 

If we had a P-40 N as well, a lot of people would be happier 

 

People also all seem to forget that the P-40 E-1 weighs empty more than a Bf109 G6 (without the 109's extra horsepower) 

 

Think about that rationally for a bit,

 

the P-40 E-1 is just not really a front line fighter any more in 1942, still an awesome aircraft which has its uses

 

Stay safe everyone

 

Cheers, Dakpilot 

The P-51A used the same V-1710-39 as our P-40E and was cleared for 57" for 5 min though.

[357th_KW]

2 hours ago, -=PHX=-SuperEtendard said:

The P-51A used the same V-1710-39 as our P-40E and was cleared for 57" for 5 min though.

 

The P-51A used a later V-1710-81.  The Mustang I, XP-51 and P-51 (aka Mustang IA) used the -39 and had the same restriction as our P-40E.  See here - also referenced in "America's Hundred Thousand" by Francis Dean.

 

In reference to some of the earlier discussion of using higher boost settings on Allison engines, this document (also from Mike Williams WWIIaircraftperformance.org) sheds some light.

[gimpy117]

12 hours ago, Dakpilot said:

 

 

 

People also all seem to forget that the P-40 E-1 weighs empty more than a Bf109 G6 (without the 109's extra horsepower) 

 

Think about that rationally for a bit,

 

the P-40 E-1 is just not really a front line fighter any more in 1942, still an awesome aircraft which has its use

 

I don't think anyone is arguing the P-40 should out-perform the 109, just that right now it's completely outclassed by the 109 unless flown in a very narrow and specific manner. My argument is, given the challenges to this aircraft especially in multi, why not allow the P-40 less restrictive engine limits on an interim basis.  

7 hours ago, KW_1979 said:

 

The P-51A used a later V-1710-81.  The Mustang I, XP-51 and P-51 (aka Mustang IA) used the -39 and had the same restriction as our P-40E.  See here - also referenced in "America's Hundred Thousand" by Francis Dean.

 

In reference to some of the earlier discussion of using higher boost settings on Allison engines, this document (also from Mike Williams WWIIaircraftperformance.org) sheds some light.

and also, if that document is real, it seems like Alison themselves were onto the open secret that the engine was rated too conservatively 

edit:

to avoid "confusion" here is what I'm saying: 

1. There is evidence to support the engine used in the P-40 In combat was used far above "rated" power settings 

2. the P-40 is considered outclassed by many aircraft it meets in historic scenarios

3.Increasing engine limits the mimic what was seemingly known to Alison and used in the field will likely not create a situation where the P-40 is "OP" or a "UFO" rather  it will make it more useful   

 

 

Edited March 31, 2020 by gimpy117

[Voyager]

Honestly, engine timers should go once they've got a good engine model. We should be able to manage the engines with the same gauges the pilots did, without requiring pop-up alerts to run core aircraft functions.

[312_Lazy]

10 minutes ago, Voyager said:

Honestly, engine timers should go once they've got a good engine model. We should be able to manage the engines with the same gauges the pilots did, without requiring pop-up alerts to run core aircraft functions.

That's exactly what I do. Pop-up alerts switched off, I use only the gauges.

[Dakpilot]

27 minutes ago, gimpy117 said:

I don't think anyone is arguing the P-40 should out-perform the 109, just that right now it's completely outclassed by the 109 unless flown in a very narrow and specific manner. My argument is, given the challenges to this aircraft especially in multi, why not allow the P-40 less restrictive engine limits on an interim basis.  

 

 

It is "outclassed" by 109 because an E-7 weighs a whole metric ton less! 

 

And F-4 is 600 kg less

 

It is unlikely even as an interim measure to give later model engine restrictions to the E-1 to create some sort MP parity 

 

8 minutes ago, Voyager said:

Honestly, engine timers should go once they've got a good engine model. We should be able to manage the engines with the same gauges the pilots did, without requiring pop-up alerts to run core aircraft functions.

 

When detonation is modelled and introduced, catastrophic failure can occur without any indicators other than time at certain power settings as IRL, indications on guages normally tell you that it has already happened rather than a warning. 

 

Having experienced many engine failures IRL 99% gave no warnings, when things go wrong with high horsepower /high performance aero engines they happen fairly rapidly and terminally 

 

Cheers, Dakpilot 

[gimpy117]

1 minute ago, Dakpilot said:

 

It is "outclassed" by 109 because an E-7 weighs a whole metric ton less! 

 

And F-4 is 600 kg less

 

It is unlikely even as an interim measure to give later model engine restrictions to the E-1 to create some sort MP parity 

 

 

When detonation is modelled and introduced, catastrophic failure can occur without any indicators other than time at certain power settings as IRL, indications on guages normally tell you that it has already happened rather than a warning. 

 

Having experienced many engine failures IRL 99% gave no warnings, when things go wrong with high horsepower /high performance aero engines they happen fairly rapidly and terminally 

 

Cheers, Dakpilot 

 random detonations are a double edged sword, better than timers

and if the P-40 weighs a ton more, whats the issue with giving it better engine timers?

[=362nd_FS=RoflSeal]

38 minutes ago, Dakpilot said:

 

It is "outclassed" by 109 because an E-7 weighs a whole metric ton less! 

 

And F-4 is 600 kg less

 

It is unlikely even as an interim measure to give later model engine restrictions to the E-1 to create some sort MP parity 

 

 

When detonation is modelled and introduced, catastrophic failure can occur without any indicators other than time at certain power settings as IRL, indications on guages normally tell you that it has already happened rather than a warning. 

 

Having experienced many engine failures IRL 99% gave no warnings, when things go wrong with high horsepower /high performance aero engines they happen fairly rapidly and terminally 

 

Cheers, Dakpilot 

The -39 and -73 Allisons wouldn't be detonating at 70"Hg manifold pressures, that would be the -81 and later engines with the larger superchargers.

[gimpy117]

that's pretty much what Alison said in the photocopy that was posted earlier in this thread, that larger superchargers could not necessarily be run at 70" HG 

[Dakpilot]

If people think that reliable 1800hp Allison's should be a thing in 1942 they are welcome to ?

 

This is late 44 109 K4 Db 605 with MW50 power levels

 

Cheers, Dakpilot 

[-=PHX=-SuperEtendard]

@KW_1979 In a Mustang I manual the limits for the V-1710-39 are 5 min for 45.5", which currently in game it's 5 min for 42",  it's a difference of 250 HP (1150 vs 900) at sea level which would be of good help currently for the P-40. Also it's noted that with a manifold pressure regulator it could use 56" for 5 min, for 1470 HP at sea level.

Imho a modification that allows 45.5" for 5 min or 56" would help greatly.