Boost and resulting torque figures.


Kozy said:
60lbft/litre



82lbft/litre




57lbft/litre

Interesting spread of figures so far. Most engines, once boost corrected will produce between about 60 and 80lbft per litre. Because there is so little variation, it's a good measure of how efficiently the engine is breathing, it's physically limited by how much air the engine can ingest, so can't be affected by loads of revs like specific power can. The stock B16B makes 73lbft/litre for reference, about midrange for a performance engine.

Looks like the standard head starts to choke a bit at high boost figures, Blinx's engine looks well developed though.
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These calculations are based on the peak torque figues how would you know how the torque is affected accross the rev range also when does it come in and how hard, for how long

is it a case of maximum airflow = peak torque ?

would you be able to get better results if you were to have airflow stats and dyno maps (on same dyno) or would it be impossible to correlate?
 
EK4 Luke said:
These calculations are based on the peak torque figues how would you know how the torque is affected accross the rev range also when does it come in and how hard, for how long

is it a case of maximum airflow = peak torque ?

would you be able to get better results if you were to have airflow stats and dyno maps (on same dyno) or would it be impossible to correlate?
Click to expand...

It's an 'at best' figure, it's closely related to BMEP which is a sort of industry standard measure of engine efficiency, engineers would regard any engine with a BMEP of over 200psi as being highly developed, which equates to around 80lbft/litre in terms of specific torque.

I'm simply interested in seeing the correlation between boost and specific torque on cars that weren't designed for it, so far it seems some of them can drop from around 75lbft/l stock NA, to below 60lbft/l, whereas a car turbocharged as stock will be built around that and also manage 75lbft/l.

Interesting to see though that some people are managing to maintain good BMEP with a turbo setup! :nice:
 
blinx9900 said:
i understand, still thats just not possible, a gt3582r simply cannot generate enough airflow to make that kind of power on a 2.0 engine. I'm guessing your dyno just reads differently or was on a wrong setting as even those numbers at the flywheel are still just way too high considering its at 7000rpm that means you'd be making close ~840whp by redline.

Let me ask you, what size fuel injectors do you run?
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It think it's 501Nm, since the power is in Kw. That would make it around 370lbft.
 
Kozy said:
Very true Rich. Could you apply a multiplier for different dynos? If so how much?

Although, I thought torque was torque, it was the power that was subject to variation?

Also do figures in the US usually come out higher than in the UK?
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Not sure about the multiplier mate, or how you'd go about it.

BHP or WHP (I believe this is what you mean by "power") is worked out by rpm and torque.... it's all linked.

As for the US dynos, well I've had this debate many times with myself. I'm really not sure though to be honest. If you've ever been there you'll know how BIG the tuning scene is and how much we actually lack behind them (Which isn't a dig at us. There only there because of there size/market/demand) and this is what makes me think there no different to ours. I just don't think that a lot of us can actually come to the reality of how it is out there.
 
What would also be useful is if people have dyno runs at different boost levels on the same setup.

Agreed on the US tuning scene Rich, it's fookin huge. If there was the kind of market here then I could eventually see myself making a leap into starting my own business in the future, but as it is it's simply too risky.
 
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Lol my numbers are weak compared to the rest, but I believe I'm the first S/C guy

Stock internal B16B (still have PS/AC)
Password JDM (same as J's) "Power-chamber" (whale pee-pee) Intake
No name Tri-y Header (2.5)
Blox Test Pipe (2.5)
HKS Windmaster 2.5 Catback
Jackson Racing S/C 10-11psi

Put down 248 whp / 160 ft lbs after several runs (was warm, maybe a little more when cool), tuned with Hondata on 91 octane.
 
dropnotch said:
Lol my numbers are weak compared to the rest, but I believe I'm the first S/C guy

Stock internal B16B (still have PS/AC)
Password JDM (same as J's) "Power-chamber" (whale pee-pee) Intake
No name Tri-y Header (2.5)
Blox Test Pipe (2.5)
HKS Windmaster 2.5 Catback
Jackson Racing S/C 10-11psi

Put down 248 whp / 160 ft lbs after several runs (was warm, maybe a little more when cool), tuned with Hondata on 91 octane.
Click to expand...

Around 58lbft/litre or 145psi BMEP which is pretty low, but generally to be expected with the parasitic loss of a SC.
 
mine made

Turbonetics T3/04E @12PSI

289.4 Wheel HP
226.1 wheel tq ft/lb

b16a2 head,
ITR Cams and Valve train,
Skunk2 Intake manifold,
ITR Throttle bodie

B20Z Block
Arias 84mm 10.5-1 cpr (11-1 cpr with b16a2 head)(according to arias stats)
Eagle Rods

222912_10150240317706348_2432528_n.jpg
 
yeah i thought that when i did the calculation

how does it differ from different dynos used??? i have heard varied power figures from different set ups ie rolling roads to dyno hubs???
 
Harvey, are you still using a cast manifold? The way i see it, everything is about flow, and cast manifolds just dont cut the mustard really, hence the low figures.
Kozy am i on the right track in thinking this?

Murray
 
harvey j said:
yeah i thought that when i did the calculation

how does it differ from different dynos used??? i have heard varied power figures from different set ups ie rolling roads to dyno hubs???
Click to expand...

Unfortunately it's never going to be a truly accurate comparison because of this.

Murray said:
Harvey, are you still using a cast manifold? The way i see it, everything is about flow, and cast manifolds just dont cut the mustard really, hence the low figures.
Kozy am i on the right track in thinking this?

Murray
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One of the many possibilities, but yes it's the right thought process. :nice:
 
Just found an impressive one.

Evo X FQ360
2000cc
10.3psi
363lbft

Gives it an effective capacity of 3400cc with an impressive 106lbft/litre or 263psi BMEP.

RalliArt showing how the pro's do it right there! :eek:

EDIT: Can't be right. Think the figures were meant to say 1.3bar, which would make it 4600cc and 78lbft/litre and 194psi. As you were....
 
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It is. I wanted to see how much variation there was with various builds on the same engine.

Quite a lot, it turns out.
 
My setup sleeved and forged b18c4 GT30 turbo made 487.1bhp and 374.5 ft/lbs@21psi :)
 
Murray said:
Harvey, are you still using a cast manifold? The way i see it, everything is about flow, and cast manifolds just dont cut the mustard really, hence the low figures.
Kozy am i on the right track in thinking this?

Murray
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when it was dyno'd it had a OBX Ram horn on it, i am using a cast at the moment as it cracked a weld on the wastegate flange.

my figures are only in wheel horse/torque, does anyone now the calculation from wheel to fly ????
 
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harvey j said:
when it was dyno'd it had a OBX Ram horn on it, i am using a cast at the moment as it cracked a weld on the wastegate flange.

my figures are only in wheel horse/torque, does anyone now the calculation from wheel to fly ????
Click to expand...

Cool, my figures are at the front wheels aswell, there isnt a calculation to convert wheel to flywheel as there are to many variables.

Murray
 
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