Finally, dyno done.

[leo]

Well, after some years, and last year ECU upgrade, finally managed to do the dyno.
This is it. dyno.jpg

Sooo, specs are as follows: GT3071R , stock intake w/o mapsensor, exhaust manifold custom, 3"pipes, AAN ecu + program by Digitun , stock internals, well ex camshaft is from 7A, but engine was rebuild as i started the journey, with metal head gasket, new head bolts etc, 01E gearbox, removed spark distributor and mounted 5 coils, red ones - pretty ones , some minor changes in chasis...

The question i am asking You to answer is: will it take some more torque on stock internals - i love the high revs, so wanted to add some Nm in 5-6,5 krpm range.
Well - i have got used to this car now. Do you think it will take, well, about 50 Nm more without higher risk ?

[Thuppu]

Nice flat torque curve! You could lift the rpm limiter some ~7800 or so.

[Cordoba16vt]

Have you thought about using an 7A inlet cam, standard inlet kills power of any bigger than standard turbo....

[prj]

Oh man...

1. Only the boost needs lifting, there is absolutely no need for more RPM
2. Standard cams are the best choice up to 500+hp. Kills power, really? This is not NA, it's a turbocharged engine. The only thing 7A inlet cam is going to do on this engine is destroy the off-boost low-end. And on the top end the same can be accomplished by increasing the boost a little.

Cams only need to be changed once you start hitting flow chokes in the head, and that doesn't happen on a GT30 turbine.

[Thuppu]

So whats wrong with wider power band?

[leo]

valve float, probably, I'm not a big fan of overrevving without removing hydro... well tappets - etka says, to the mechanical springs

[DeS]

Adam, what's the boost pressure?

[leo]

Czekałem na Ciebie tutaj, Des

it's 1.7 bar almost in the whole range.

[prj]

So whats wrong with wider power band?

Nothing wrong with power band, but if it was running correct boost for the application, then after 6500 RPM the torque would nosedive and revving any further than 7200 would be utterly pointless anyway. Except in 1st gear it could use a 7500 rpm limiter to hit 1->2 transition.

Also stock rods can even break at this power due to metal fatigue. They are just so old and have gone through so many stretch/compress cycles (especially at high RPM), that they can snap in half for no visible reason. I'd change the rods at the very least just to be safe. And then run 2.1 bar boost.

[JariP]

Power has nothing to do with rods and fatigue, only the moving masses and rpm's matter in that respect.

[prj]

Power has nothing to do with rods and fatigue, only the moving masses and rpm's matter in that respect.

That was exactly the point of my post. They can snap for no reason at any power when the engine has done 200 000 hard km's. I've had that happen.

[Acki]

Mass forces are in the opposite direction. Torque in low rpm can break them too. Gas force is much higher than mass force.

[Tom_]

prj So for 2.5 stroker engine will be best solution to use AAN/3B cams, wont be? To have strong low end, than high rpms

[prj]

It depends on the amount of flow you are trying to push through the head... really there is no magic answer.
If you start hitting flow chokes on the top end then you will need a cam with bigger lift. But bigger lift will also kill low end....

[Error404]

No free lunch.

Bottom line, increased RPM = increased stress on the rotating assembly at an exponential rate.
If you can move more air mass at a lower RPM then do it