Boost and resulting torque figures.


Kozy

Kozy

Bench Racer
Vendor
Joined
Aug 18, 2008
Messages
4,081
I'm doing a bit of research into specific torque figures, particularly on boosted engines. Those of you that have dyno figures, would you mind posting what torque you made, what capacity you have and how much boost was used? Also a bit on any headwork you have would be helpful. :thanks:

This doesn't necessarily need to be your car, any figures would be helpful as long as they are dyno proven.
 
Last edited:
On my car, peak of 1 bar boost on my 81.5mm bore b16, i get 195 lbsft at the front wheels. Stock head apart from EK9 cams.

Murray
 
81.5mm bore b16a block pr4 pistons
b16b head with all b16b internals plus 3 angle valve job
GT3076R turbo with supporting mods 12psi 240lb of tq
 
Murray said:
On my car, peak of 1 bar boost on my 81.5mm bore b16, i get 195 lbsft at the front wheels. Stock head apart from EK9 cams.

Murray
Click to expand...

60lbft/litre

blinx9900 said:
81.5mm bore b16a block pr4 pistons
b16b head with all b16b internals plus 3 angle valve job
GT3076R turbo with supporting mods 12psi 240lb of tq
Click to expand...

82lbft/litre


V-TEC ABUSER said:
81.5 mm B18 block, 1.5bar of boost and i get 260Ibsft torque.
Click to expand...

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.
 
Last edited:
When mines done I'll let you know the results. I've got a set of GSC turbo cams fitted along with a bit of head work done.

P.S. you need to consider (some how) the dyno the car's been tuned on as well. We all know how low a "Dynodynamics" reads compared to a "Dynojet".
 
Last edited:
Out of curiosity, what do you mean boost corrected? And how are you working it out?

Also wouldnt inlet and exhaust manifolds, exhaust turbo size play a part in the engines cabability to breathe at high boost?

Murray
 
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?
 
Last edited:
Id say the US WHP figures are our flywheel figures, thats what it seems to me IMO
 
Murray said:
Out of curiosity, what do you mean boost corrected? And how are you working it out?

Also wouldnt inlet and exhaust manifolds, exhaust turbo size play a part in the engines cabability to breathe at high boost?

Murray
Click to expand...

Swept volume * MAP = Effective capacity. (MAP = Boost/gauge pressure +1, in BAR)

So a 1.8 running 0.8 BAR would be 1.8 x 1.8 = 3.6 litres

Torque / Effective capacity = Specific torque.

270lbft / 3.6 = 75lbft/litre

As you say, intake and exhaust affect it, it's all part of the engine's breathing capability. Restrictive or poorly matched system = low figures. Well developed, free flowing and matched = 80+lbft/litre.
 
Last edited:
Kozy said:
Swept volume * MAP = Effective capacity. (MAP = Boost/gauge pressure +1, in BAR)

Torque / Effective capacity = Specific torque.

As you say, intake and exhaust affect it, it's all part of the engine's breathing capability. Restrictive or poorly matched system = low figures. Well developed, free flowing and matched = 80+lbft/litre.
Click to expand...

Cool cheers for the info

Murray
 
11.5 CR
Standard Bore
N1 Race Cams
Peak Boost Manifold
GT3582R

Peak Power 215kw ATW 7,PSi
Peak Torque 501lbs (7000rpm)
 
Last edited:
Kozy thanks a lot :) i take that as a compliment :) i have no traction till third gear, and thats with 15" nitto nt01's after a burn out L:(


DIY_EK2142 said:
11.5 CR
Standard Bore
N1 Race Cams
Peak Boost Manifold
GT3582R

Peak Power 215kw ATW 7,PSi
Peak Torque 501lbs (7000rpm)
Click to expand...

There is something wrong with this, with the information you would be making 668whp at 7000rpm with those torque figures, such is usually not possible using a GT35R and especially not on only 7psi.
 
Last edited:
yes it does sounds wrong but that what it says on my dyno sheet. (Will put it up once i get my scanner working)

also should note that i do have a hi-comp fully built 2.0L motor.
 
DIY_EK2142 said:
yes it does sounds wrong but that what it says on my dyno sheet. (Will put it up once i get my scanner working)

also should note that i do have a hi-comp fully built 2.0L motor.
Click to expand...

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?
 
using the calculations given.. does this mean my Toyota Glanza is producing 60lbs ft/ litre

1.3 running 0.8 Bar and made 142 Lbs ft. standard bore is 74mm
 
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?
Click to expand...

Bosch 1200cc
 
Last edited:
You must log in or register to reply here.
Back
Top