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Strange Dyno Results???

mr_rbman

By mr_rbman,
in General Automotive Discussion

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mr_rbman Grand Master

mr_rbman

Posted
Posted

OK, had my car dynoed yesterday and i got some strange results i THINK, its a 1992 R32 GTS-T manual with what i presume is an RB20DET ECCS!

The only mods i have are:

Full 3" mandrel bent exhaust

Hot air pod

11 PSI and 13PSI (dual stage boost controller0

now i made 149rwkw's on 11 PSI and 159rwkw's on 13 PSI but the strange thing was the amount of torque i made. I made 417.2NM of max Torque at 11 PSI @ 127 kph and 435.0NM of max torque at @94kph.

Now i'm no expert but isn't that a lot more torque than what they are supposed to be putting out?

Anyone with similair mods can you please tell me how much torque you have?

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NA_R33 Grand Master

NA_R33

Posted
Posted

tractive effort is whats read on a dyno, it is relative to things like the gear ur in, ur diff ratio and other things, in first gear im sure ur car will make over a 1000nm's on a dyno, u cant measure torque on a chassis dyno, only an engine dyno.

NA_R33 Grand Master

NA_R33

Posted
Posted

it varies hugely between dynos gear ratios diff ratios lots of things, had this argument with an idiot telling me my car wasnt capable of making the torque (tractive effort in this case) that i claimed. I cant say wether or not its right as im not hugely familiar with rb20's and dont know what gear you were in, basically dont concern urself with it, only use it as an indicator next time u have ur car on the dyno if say u have done mods...

NA_R33 Grand Master

NA_R33

Posted
Posted

another interesting point, two identical engines but one auto and one manual, the auto will make more torque/tractive effort on a dyno with less power but the manual will make less torque with more power...

Cubes Grand Master

Cubes

Posted
Posted

I'm more interested at the RPM or km/h that the peak torque was made.

It may be that on 11psi boost holds constant through the rev range allowing peak torque to be made higher in the rpm.

On 13psi the boost may peak up then being to taper off maybe half a psi to 12.5psi. This will cause torque to drop slightly in the higher rpm as boost has dropped slightly. Or it may have spiked to say 14psi then settled on 13psi giving the higher peak torque at a lower rpm. :cheers:

Reason I speculate is this is what mine did with a bleeder.

I fitted an EBC and boost was held at what it was set to right until thr 7500rpm cut. No matter how much boost I pumped in to it 15-16psi it would still drop to 12.5psi over 5500rpm.

I later sold the EBC and modified the wastegate actuator's bracket so I could reduce the travel which forces boost to be held in the higher rpm's, just like an adjustable rod.

159rwkw is a good result for 13psi.

I would assume your AFR's are fairly sorted, which means your fuel pump is near its limit.

Cubes Grand Master

Cubes

Posted
Posted

Running richer definitely drops power.

Mine went from around 153rwkw on 12.5psi with an afr of 11.8 to 135rwkw on 12.5psi by simply dropping in a new fuel pump.

It ran hell rich and blew a bit of black smoke on the dyno.

So the fuel pressure was played with and power came back up.

On 1bar with the new fuel pump & standard fuel pressure the car made 150rwkw.

With fuel pressure adjusted to lean out the afr's power came up to 164rwkw.

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