Control over boost pressure...

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STICH666

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xSTICH666x
Hey guys. I've always wanted to do this in a game with half decent physics just to see the result but wouldn't it be awesome if we could adjust the boost pressure of our turbo or supercharger. You could in Sega GT 2002 so why not this game 10 years later? Also I think this would solve the low hp issue for most cars in the game. Why a 2.2L can only make 250hp even with a stage 3 turbo and forged internals is beyond me....
 
Yeh itd be great, buy a standard evo and wind it up for a free power increase

Whether you're aware or not the japanesse had a gentlemans agreement to keep max bhp below 276(I think) on any cars they built. Some skylines came with a way to de-restict the boost to get higher bhp that nissan knew the cars could handle, look up the skyline/gt-r page on wikipedia
 
No that only affects when the boost is applied not really how much power. It's saying you could get a lower rpm turbo for less power but lag or a higher one for more power but more lag. I don't see why you can't just crank it up to 60psi and have a go like in Sega GT 2002. I had a 1971 Camaro Z28 that when cranked up to 60 psi it would develop way more than 1000hp but it would melt the block after each race.
 
Yes, it would be a good feature to have. If I recall, you used to be able to adjust it in the original GT, but not in any of the others. Wonder why they haven't included it since?
 
STICH666
No that only affects when the boost is applied not really how much power. It's saying you could get a lower rpm turbo for less power but lag or a higher one for more power but more lag. I don't see why you can't just crank it up to 60psi and have a go like in Sega GT 2002. I had a 1971 Camaro Z28 that when cranked up to 60 psi it would develop way more than 1000hp but it would melt the block after each race.
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Lower rpm turbos spool quickest and make least power.
Mid-range turbos spool more slowly but make more power than low-rpm turbos.
High-rpm turbos spool the slowest but have highest peak hp.

Which is generally the way turbos work in real life. The quickest spooling turbos are the smallest turbos (which are also the lowest hp turbos). The highest HP turbos are large but also take longest to spool.

Turbochargers have an efficiency range they operate in. In real life, you can't just "crank it up to 60psi".
 
Well you know what I mean. Like why can't we take it up to its peak efficiency. There's no way that a Ford RS200 can only make 350hp
 
STICH666
Well you know what I mean. Like why can't we take it up to its peak efficiency. There's no way that a Ford RS200 can only make 350hp
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Well, I agree the car is capable of producing more power,

-BUT-

If you read the Wiki entry on the RS200, this part seems relevant: Power came from a 1.8 litre, single turbocharged Ford/Cosworth "BDT" engine producing 250 horsepower (190 kW) in road-going trim, and between 350 and 450 horsepower (340 kW) in racing trim; upgrade kits were available for road-going versions to boost power output to over 300 horsepower (220 kW). Although the RS had the balance and poise necessary to be competitive, its power to weight ratio was poor by comparison, and its engine produced notorious low-RPM lag, making it difficult to drive and ultimately less competitive.

So, it seems like maybe the tuning options are somewhat accurate for that period. Also, if you look on here: http://mygranturismo.net/car_sheet.php?id=226, someone listed 425hp as the maximum HP, not sure if that's correct though...
 
I agree that boost pressure should be adjustable, much like it is on many aftermarket turbo systems in real life. Boost from superchargers is usually changed by changing the pulley.

But then again, this game is missing many things that should be able to be adjusted, tire pressure for example.
 
shigllgetcha
Yeh itd be great, buy a standard evo and wind it up for a free power increase

Whether you're aware or not the japanesse had a gentlemans agreement to keep max bhp below 276(I think) on any cars they built. Some skylines came with a way to de-restict the boost to get higher bhp that nissan knew the cars could handle, look up the skyline/gt-r page on wikipedia
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Fairly certain that it was a law, not a gentlemans agreement.
 
shigllgetcha
Yeh itd be great, buy a standard evo and wind it up for a free power increase

Whether you're aware or not the japanesse had a gentlemans agreement to keep max bhp below 276(I think) on any cars they built. Some skylines came with a way to de-restict the boost to get higher bhp that nissan knew the cars could handle, look up the skyline/gt-r page on wikipedia
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It was an agreement, but almost none of those cars really had 276bhp.
 
If they simulated engine damage properly, and simulated catestrophic engine failure....Allowing control (especially realtime) of the boost pressure would be great....I hope T10 are reading.
 
EivlEvo
Fairly certain that it was a law, not a gentlemans agreement.
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It definitely wasnt a law

D_B_Coop
It was an agreement, but almost none of those cars really had 276bhp.
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Some skylines maybe but most cars stuck pretty close to it untill recent years

Anyway it was just an example of where boost control would be usefull
 
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charliec
Also, if you look on here: http://mygranturismo.net/car_sheet.php?id=226, someone listed 425hp as the maximum HP, not sure if that's correct though...
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Mine has 422 bhp from a permanently worn engine. 425 sounds about right for a brand new car.

TooFast89
I'm pretty sure the Ford RS200's bdt engine is capable of pumping out close to 700 BHP.
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Even the old Volvo red block as seen in the 240 GLT can put out over 800 bhp in real life (in a daily driver no less) if we're talking about what the engines can do. If it's sensible is another thing but I have a feeling PD thought about that side too.
 
Greycap
Mine has 422 bhp from a permanently worn engine. 425 sounds about right for a brand new car.



Even the old Volvo red block as seen in the 240 GLT can put out over 800 bhp in real life (in a daily driver no less) if we're talking about what the engines can do. If it's sensible is another thing but I have a feeling PD thought about that side too.
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By sensible you mean, politically correct? Yes
Do not forget that adjusting the turbo pressure could also mean lowering it.... kind of like the air restrictor plate (power limiter) on GT5. ;)
 
Mr. CoolFiat
By sensible you mean, politically correct?
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More power does not always mean faster, especially on a racetrack. Running massive amounts of boost through an engine and chassis that were never designed for that power can create all sorts of drivability problems.

Yes, you may be fast from stoplight to stoplight, and you'll have impressive dyno numbers to show off with. Try and run it around a tight circuit though and once your turbo spools up and you suddenly go from 300HP to 750HP in the space of 1000RPMs, you're going to be facing the wrong direction with a quickness.

Turbo lag and a peaky power delivery is never a desired trait in racing, especially in anything that requires braking and turning.
 
Well yes but there are cars that could REALLY use it. My Ford Ka is a great handling little thing but is soooooooo underpowered that it's unraceable. Same goes for any Japanese car in this game pre 1985.
 
The tuning in GT has always had a few issues. Many of the cars featured in GT can produce way more power tuned in real life than they can in the game.
 
What they should do is have a power/effeciency slider so you can crank the power right up but if you keep it on high power all the time you will have to rebuild the engine after 10 races.
 
That's essentially what Sega GT 2002 had. You could run about 5 races at 60psi but you would have to rebuild the engine depending on the car since muscle cars would last longer .
 
STICH666
That's essentially what Sega GT 2002 had. You could run about 5 races at 60psi but you would have to rebuild the engine depending on the car since muscle cars would last longer .
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That's perfect and it's exactly what I was thinking about 2 days ago...

Even GT1 had boost control in levels... you bought a turbo and never had it set in the highest pressure by default.

Then you just went to the car tuning settings and raised it to the last level.

Yeah... I would love that... you can adjust the boost but then you'll have severe engine wear.

It's just perfect.

Just wish PD read that...💡💡
 
My understanding of the turbo upgrades is that the three stages are "sizes" of the turbo (rather, turbine / compressor pairing) such that the peak efficiencies (hence torque) sit in a different part of the rev range depending on the kit you buy.

This is why the kits are low / mid / high rpm, since they are tuned for volume throughput, which ultimately only determines their maximum possible boost on a given-sized engine. Tweaking the wastegate (i.e. how much of the exhaust throughput actually gets used) allows for boost control - i.e. the "bump" in the torque curve produced by the action of forced induction can be scaled so that it blends into the (pseudo-) NA torque curve (no boost), or stands out on its own (maximum boost). As a result, the boost controller makes more sense now than it ever did in any previous version of GT, where turbo upgrades were sold in "stages", which could mean anything.

Obviously, there comes a point where scaling the exhaust flow via the wastegate leaves too little volume to actually push the turbine around and compress the charge air, hence dropping boost off dramatically. That is, the minimum practical boost is also determined by the kit size, and should be lower for the lower rpm range kit than it is for the high-rpm kit. Ideally there would be an overlap of practical boost ranges for each kit, meaning that the same peak torque figure should be possible on two adjacent kits, but the location of that peak in the rev range will be different.


In short, I agree that boost control is very relevant and useful in tuning cars for many reasons, not just peak numbers. I don't like the way the mid-rpm kit tails off at higher rpms, for instance. I'd probably prefer to run the high-rpm kit at a lower boost level - I know I could use the power limiter, but a wastegate actually acts as a torque limiter, so it's not the same. Then there's the possibility of welding the wastegates shut, as they did in F1 and LeMans in the '80s (in particular), and some of the Group-C numbers only make sense with that in mind. It should be noted that the hardware didn't like this maltreatment, so I agree that engine (and drivetrain?) wear should account for this somehow.

The torque-scaling resulting from boost control in GT seemed sensible and "realistic", so I don't see why it's been excluded ever since; except for the engine wear issue.
 
I would have thought that due to a supercharger running from a belt drive and not powered by pressurised gasses like a turbo then there would be no option to adjust 'boost' unless the 'boost' you are referring to is the pressure from the forced air induction and this is what you wish to regulate.
 
shem
I would have thought that due to a supercharger running from a belt drive and not powered by pressurised gasses like a turbo then there would be no option to adjust 'boost' unless the 'boost' you are referring to is the pressure from the forced air induction and this is what you wish to regulate.
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With a supercharger, adjusting the pulley ratio changes the volumetric flow through the charger by rotating it faster relative to the engine's crank.
This volumetric flow, versus what the engine "should" be receiving at the given crank speed, is what gives rise to part of the boost level. (Most superchargers, except centrifugal types, are of the positive displacement type and so have an internal pressure ratio.)
There are still ways to limit boost on any supercharged engine on top of tweaking the pulley ratio, such as through bypassing or bleeding the charge air etc.

To answer your question, though, yes "boost" is always referring to charge (intake) pressure, not exhaust, and is linked to volumetric efficiencies typically much greater than 100%. E.g. a sustained boost of 14.7 psi g = 1 atm g ~ 1 bar g (boost is always measured in gauge pressure) would give something like 200% peak V.E., depending on the breathing apparatus.

The peak VE (i.e. boost) gives rise to peak torque, and the VE vs. rpm graph is the same shape as the torque vs. rpm graph, assuming "perfect" ignition and fueling.
This is why a boost controller is useful, since it's effectively a torque controller.
 
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Unfortunately GT5 models nothing (or very very few) of these details.
I'm doubtful we will see something more advanced for tuning in this game in future patches.

That's what frustrates the most about this game by the way.
I'd like more detail, more control and realism over several (many actually) aspects, but fact is that the current (old-school, arcade-like) simplicistic approach is due to deliberate game design choices that won't likely change.
 
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I miss this feature from GT1. It would definitely be handy if it was included again.
 
Ever think about the fact that GT5 is doing one too many things? GT5 is trying to give you depth but not too much as to where the average person can't get into the game or new comers will be turned off by the amount of daunting options. While I would love GT5 to give me a lot more things, wanting to tweak boost pressure would require a lot more calculations that you might think, engine temps need to be added, engine life would also have to be tied into usage of over boosting, everything having to do with the engine from intake to exhaust, to cam pressure would need to be modeled in order to make sense. PD is probably heading in that direction, but you just can't have everything right now. That would be interesting to have someone over boost and have his engine fail after driving around the Nur for 5 laps at high boost. Then that hefty price tag for engine rebuild would make sense. Right now PD can somehow implement a boost controller and maybe an ECU control. I hate not being able to map out the power especially when you tend to use the same car for different PP races, just transmission tweaking isn't enough. I will continue to play and let my voice be heard for more additions to GT5 in the form of updates. Right now some of the standard super cars have terrible down force miscalculations, the Saleen S7 and all three Zonda's drive like they are on ice, not a tire physics issue its complete lack of down force, these cars especially the S7 have incredible down force that helps keep them on the road, but when I drive it it tends to hop off the road easily and it's lateral grip is lower than it's supposed to be because of lack of down force.
 

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