Gtr 26/30 With Cams And -5S

[R32 TT]

You're at lower revs....

[rob82]

So if you are making more torque and roughly the same power what is happening? (i.e. assume RB26 vs RB30)

In terms of what?

[bigmikespec]

How are you making more torque without using more fuel?

[Marko R1]

You're at lower revs....

good point!

How are you making more torque without using more fuel?

haha - exactly

[R32 TT]

Um..... Because it's doing less revs.....?

[Marko R1]

Um..... Because it's doing less revs.....?

yes, higher revs duty cycle increases

[J - Rad]

yes, higher revs duty cycle increases

Exactly, so if you're making more torque at lower RPM, how is the RB30 using more fuel with the torque rush?

[R32 TT]

Thankyou.. . I was wondering how the point was being missed...

[Marko R1]

lets use a real life example here...

paul diemar with his drag car TWOOGLE;

when he had the car tuned with the standard head it was within duty cycle of his injectors.

he then had head work done which gave him similar peak power, however, the torque increased substantially.

as a result, he maxed out his injectors & upgraded these to suit.

i only wish he was still on this forum to set the record straight

[R32 TT]

Marko I think you're just getting confused mate.

I don't doubt Paul made more torque with the mods he made. And what he was saying was that he was making more torque "at a given revs or range", ie he was making more horsepower at that rpm range. And if you are making more horsepower (as a result of more torque) then you need more fuel.

So the point is: Its not a RB30 that 'needs bigger injectors' because of the extra torque it makes.

Based on that theory, a 510 Cube V8 making shitloads of torque but only 400hp needs bigger injectors than all of us!

Also think about this. You sometimes hear people say 600cc Injectors can support X amount of 'horsepower' (ie Torque x RPM). You never hear people say 600cc injectors support x amount of 'torque'.

Here is another example.. suppose you have two motors, an RB26 and an RB30 that both make the same Horsepower. But that the RB30 makes more torque (usually at lower revs right?)

Lets say the RB26 makes 400ft/lb of torque at 8000rpm. HP = Torque x RPM / 5252.. therefore about 609hp.

Lets say the RB30 makes 500ft/lb of torque at 6400rpm. Do the Maths = about 609hp.

The RB30 makes more torque, but it only needs the same injectors to support 609hp.

What Paul was telling you (most likely) was that he now made even more than 500ft/lb of torque at 6400rpm (and therefore made more horsepower) which of course requires more fuel. (Obviously Paul makes more than that - I am just using the figures from the example I made up)

Make sense?

[KiwiRS4T]

Well theory and flow charts are fine and can be helpful but I'll just reiterate that two different top tuners (one a Japanese tuner who gets most of the best GTRs in NZ and the other a very experienced RB man with a 7 second R32) both of whom use hub dynos and all the gear ( including fuel pressure gauges - can't believe the number of posts I've seen here of people saying the tuner "thinks there may be a fuel problem" - doesn't he know how to tell?) are independently saying when tuning between 300 - 400kw that for a single in tank pump the Nismo ones don't hack it and the O44 do.

[R31Nismoid]

Thing is everyone is using Nismo's here without a problem @ 400rwkw

[fatz]

all pumps come alive when you direct power feed them

simple

[Marko R1]

i surrender looool

[fatz]

then skidz!

[DVS JEZ]

Marko I think you're just getting confused mate.

I don't doubt Paul made more torque with the mods he made. And what he was saying was that he was making more torque "at a given revs or range", ie he was making more horsepower at that rpm range. And if you are making more horsepower (as a result of more torque) then you need more fuel.

So the point is: Its not a RB30 that 'needs bigger injectors' because of the extra torque it makes.

Based on that theory, a 510 Cube V8 making shitloads of torque but only 400hp needs bigger injectors than all of us!

Also think about this. You sometimes hear people say 600cc Injectors can support X amount of 'horsepower' (ie Torque x RPM). You never hear people say 600cc injectors support x amount of 'torque'.

Here is another example.. suppose you have two motors, an RB26 and an RB30 that both make the same Horsepower. But that the RB30 makes more torque (usually at lower revs right?)

Lets say the RB26 makes 400ft/lb of torque at 8000rpm. HP = Torque x RPM / 5252.. therefore about 609hp.

Lets say the RB30 makes 500ft/lb of torque at 6400rpm. Do the Maths = about 609hp.

The RB30 makes more torque, but it only needs the same injectors to support 609hp.

What Paul was telling you (most likely) was that he now made even more than 500ft/lb of torque at 6400rpm (and therefore made more horsepower) which of course requires more fuel. (Obviously Paul makes more than that - I am just using the figures from the example I made up)

Make sense?

Cylinder filling is at max at max torque, therefor there is the most amount of air in the cylinder and requires MORE fuel to achieve the same afr.

So the more the engine can fill (cubic inches and boost etc) the more air is in and more fuel is required.

Max injector duty cycle should be at max torque

[KiwiRS4T]

Cylinder filling is at max at max torque, therefor there is the most amount of air in the cylinder and requires MORE fuel to achieve the same afr.

So the more the engine can fill (cubic inches and boost etc) the more air is in and more fuel is required.

Max injector duty cycle should be at max torque

You are forgetting that the cylinder will be filled more times per minute at higher revs. Demand for fuel will increase (more duty cycle) but increase in demand will not be linear if torque drops off so duty cycle curve should have more in common with power curve than torque curve.

But to get back to reading what the OP said: his tuner told him that the Nismo was running out of puff but when he hooked up a 040 it went fine. How can you argue with that? Do you want him to tell the tuner " other people can do it why can't you"?Although I would get a 044 intank.

[JonnoHR31]

Cylinder filling is at max at max torque, therefor there is the most amount of air in the cylinder and requires MORE fuel to achieve the same afr.

So the more the engine can fill (cubic inches and boost etc) the more air is in and more fuel is required.

Max injector duty cycle should be at max torque

no, max injector opening time is at max torque. max IDC is at max power, assuming of course that AFR's and timing are normal.

[N1GTR]

Scooby, has this been fixed?

Did you get a good result?

[Scooby]

Hi everyone

Just got a dyno print of 351.4 rwkw but no info re afr/psi/rpm. I'll post something when I know.

Cheers

Mark