Getting ready for the RR

wouldn't want to run 1.2 bar on a stock 3SGTE with the MR2's cooling arrangement.

a GT4 with 1BAR, exhaust, decat and intake hits 300.
 
Maybe I am missing something but that graph you showed looked awfull odd.

At 2000rpm it says you have 20bhp but 140nm torque

Also I had always thought that if your torque curve and power curve did not cross over at 5252 rpm then something was wrong with the dyno or the correction factor because the formula for calculating hosepower from the torque figure obtained from running on the rolling road (don't forget they can only measure torque, bhp is a calculated figure) is

torque X rpm / 5252

so from this you can see that when the RPM is at 5252 the HP and the torque are the same. If the power and torque lines do not cross here on the graph then someone is telling you porkies!
 
Entai said:
Maybe I am missing something but that graph you showed looked awfull odd.

At 2000rpm it says you have 20bhp but 140nm torque

Also I had always thought that if your torque curve and power curve did not cross over at 5252 rpm then something was wrong with the dyno or the correction factor because the formula for calculating hosepower from the torque figure obtained from running on the rolling road (don't forget they can only measure torque, bhp is a calculated figure) is

torque X rpm / 5252

so from this you can see that when the RPM is at 5252 the HP and the torque are the same. If the power and torque lines do not cross here on the graph then someone is telling you porkies!
Click to expand...

Read again and notice the graph is in Nm, if it was lbft then it would cross
 
Bear said:
Read again and notice the graph is in Nm, if it was lbft then it would cross
Click to expand...


I did that but the figures still are out.

At 5252 the graph shows hp as 240 and torque as pretty much peak value of 318Nm

Convert Nm to lbft you get 234.5 lbft so we are still not at 240 like the graph shows.

There is a fault somewhere in the figures.
 
Why is there nearly 100bhp of transmission loss? I thought mid engine rear drive was about the most efficient you could get?
 
[TW]Fox said:
Why is there nearly 100bhp of transmission loss? I thought mid engine rear drive was about the most efficient you could get?
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I was thinking the exact same thing. (well possibly not as that would be scary :p)

Does seem a awful lot to lose.
 
L0rdMike said:
1.2 bar is ment to take the Rev3 MR2 to around the magic 300 mark. :D

CT20b, my engine is pretty much the same as yours bar a few things.
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My mate got 295BHP from 1.2 bar, air filter and exhaust (inc decat). 300BHP would probably need a better intercooler (or a chargecooler)
 
Powerstation reads low at the wheels, its due to the type of rollers and is factored into the fly calcs.

My cousins stock Rev 3 made 268bhp at a diff RR to powerstation
 
[TW]Fox said:
Why is there nearly 100bhp of transmission loss? I thought mid engine rear drive was about the most efficient you could get?
Click to expand...

Hi there

Lets not start that again!
Some people have short memories.

Remember the last RR thread regarding everybodies having huge tranmission losses? Its PowerStations rollers for some reason give very in-accurate at the wheel figures.

The guy from PowerStation posted here and explained why and said to not take any notice of them as their RR is calibrated to give very accurate flywheel figures which is certainly does from the results people were getting.

You are right Fox a mid-engine RWD car has the fewest tranmission losses, I think its something around the 10% area. FWD cars lose approx 12%, RWD approx 15% and AWD/4WD lose approx 20-25% I think. :)
 
For reference

My own MR2 made 259.5BHP on standard boost (but with Apexi and Mongoose - cat still in place)
 
you can't work on percentages thou, which is why you should take all RR results with a pinch of salt
 
Gibbo said:
Hi there

You are right Fox a mid-engine RWD car has the fewest tranmission losses, I think its something around the 10% area. FWD cars lose approx 12%, RWD approx 15% and AWD/4WD lose approx 20-25% I think. :)
Click to expand...

It's the same arrangment for mid engined and fwd cars.. :confused:
 
I know nothing about rolling roads but considering the measure ments they take are from the rollers and therefore the wheels how can they have inaccurate at the wheel figures and yet spot on at the fly figures?

Surely if the original at the wheel figures are off then everything calculated from them will be off too :confused: Then again I could be completely wrong :o
 
i just got my new exhaust and manifold fitted, may clean it before hand, jetwash or something just to get the dirt and mud off....
 
Gibbo said:
Hi there

Lets not start that again!
Some people have short memories.

Remember the last RR thread regarding everybodies having huge tranmission losses? Its PowerStations rollers for some reason give very in-accurate at the wheel figures.

The guy from PowerStation posted here and explained why and said to not take any notice of them as their RR is calibrated to give very accurate flywheel figures which is certainly does from the results people were getting.

You are right Fox a mid-engine RWD car has the fewest tranmission losses, I think its something around the 10% area. FWD cars lose approx 12%, RWD approx 15% and AWD/4WD lose approx 20-25% I think. :)
Click to expand...

Why does mid engine have less loss than FWD?
 
austinpowers said:
What difference does steering make? It's transmisson loss after all and most mid engined and rwd cars have cv joints.
Click to expand...

Could be the style of gearbox they use for them?
 
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