RE: BHP vs Torque - advice

[GTti]

On from the recent topic, what do you think will be better? Look at the two graphs the revs the torque and power. Imagine using the gears and what revs you're in when taking a corner on a track - or the beneifits of changing up a gear earlier to produce the quick torque and power response midrange?

What about reliability? Strain on the box and clutch / drivetrain with more torque, but less strain on the engine as no need to continue past 7,000RPM.

I could have two MAP's on the ECU and simply swap turbos over depending on the track, I can imagine that graph 2 would be better for a fast track like Castle Coombe, yet 1 could be beneficial to a more twisty circuit.

Someone must of had the experience of both setups in a GT world. The specific guy with these printouts told me he's going back to the standard turbo - it feels faster and response is impressive and he doesn't run out of gear.

I must also mention that the pronounced drop off on graph one wouldn't be as bad as in the graph - this is because the boost was dropping off.

Standard 18psi

Hybrid (Larger compressor) 18psi

 

[sx_turbo]

personally i would have graph 1.

graph 2 would be great for drags, but not so great on a circuit.

graph one with the extra torque will help you pull out of corners.

say with graph one, you can take a corner in 3rd gear at 5000rpm, and have great pull out the corner, because of the torque.

where as with graph 2 with the same corner, you would struggle to pull out of the corner, in 3rd gear as the torque is not as good, so would possibly have to drop down a gear to 2nd and rev at 6500 - 7000 rpm.

so more strain will be on the engine and gearbox with graph 2 compared to graph1.

the above is just circumstantial, and is not true, it was just used as an example.

 

[Phil]

i imagine it would definintly be EASIER to get a respectable time with the first graph on a tight circuit, but if your had some good practice and werent worried about conrods giving up at the higher revs the second tune could really work well.

Phil

 

[GTti]

Standard

RPM 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000

BHP   40   64   88  118  135  149  155  158  152 (147)

LBS   90  113  135  150  155  154  149  138  124 (110)

Mean BHP = 118(120)

Mean Torque = 134(131)


Hybrid

RPM 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000

BHP   26   48   68   87  110  124  142  160  174 (180)

LBS   65   82   98  118  126  128  137  141  139 (137)

Mean BHP = 104(112)

Mean Torque = 114(103)

Woo code works on here, great.

Well I found this interesting, I put the data to values. You can see the midrange is really good on the standard turbo, yet dispite the boost tail off at high RPM - it still performs well.

It makes you think, you could well have xxx amount of horse power with a hybrid, yet the mean horse power across the range may be substancially lower.

 

[Dan3SGTE]

thats pretty interesting above.

 

[Texx]

If you didnt have the boost drop off with the standard turbo @ around 5500rpm and the torque stayed a bit flatter as in graph 2, then I'd probably be questioning the advantages of the hybrid?

Or maybe the hybrid is not quite as efficient as it could be running 18psi?

Was there a problem causing the boost to drop of with the stock turbo, or is this normal?

 

[GTti]

Was there a problem causing the boost to drop of with the stock turbo, or is this normal?

It was a different exhaust housing with a larger wastegate hole meaning it was far easier to bleed off exhaust gasses. This doesn't happen with the stock housing.

Although I have the same modifications as the standard graph, my wastegate can't open fully due to fouling on the downpipe slightly. In this case that's a good thing - I should be able to sustain the boost.

 

[gv1.3]

interesting info.

And of course code works

 

[Texx]

I supose without seeing a graph from a stock turbo that doesn't drop boost and a hybrid running more pressure, I'd say the stock turbo would be the best all rounder on a track.

Problem is you'll never really know until you experience both setups first hand.

 

[Dan3SGTE]

each turbo used above has their own benefits at the end of the day... If you went on a long straight line speed run the car with the 2nd graph will come out faster on top, around a circuit you can see blatantly that the 1st graph will prove that bit more useful(depending on what track) i.e a shorter sprinting track with very tight low speed corners.......

Couldnt say what i'd prefer, as they are different. 1st graph for everyday drivability, but then 182HP would be awesome fun in a charade lol

 

[Timmy]

I would say the 2nd graph will ultimately provide faster lap times it would be plenty easy to keep on the high side 5500 on circuit but it will be alot easier to drive on the 1st set up particuarly on the street.