[zsapphire7]

Originally Posted by AlterZgo

Torque will virtually always drop off at the top end. Remember that torque and hp curves cross at 5252 RPM because they are directly related by this formula:

horsepower = torque x RPM/5252

I really dont think you guys get it... the reason why Hp is nearly flat for 5k+ to 7K is because torque drops off. Im just asking what the limitation is thats causing this.

And no, tq doesnt always drop off at the top end. Just look at the m3 dynos. I used to think it dropped off for the n54 because boost tapers on stock turbos, and obviously theyre too small so efficiency dies off or not enough fuel to support the top end. But now that those issues have been resolved, there must be another bottleneck.

[mithiral67]

Originally Posted by zsapphire7

is it because theres only so much time the injectors can be open to deliver fuel? Im just asking for what the bottleneck is.

With the numbers they are pushing, they are running 80% above stock power and 250% over a similar NA engine. I feel like there can be a lot of limiting factors from fuel, turbo efficiency, air flow, exhaust, and stock internals

[Pepe_pr]

sexy dyno sheet

[dzenno]

Originally Posted by mithiral67

Because the amount of power to generate 450 torque at 6.8k rpms is way outside the power range of these engines.

LOL Who told you that? Soon you'll find out this motor held A LOT more than that stock internals, with the "proper" fueling

[Joe@TopGearSolutions]

Great Numbers

[GeorgeSmooth]

Awesome graph. Pity about the ASR part.

[pentaxis]

Great stuff so far!

How much boost are you willing to run with race gas, upgraded turbos, Meth, and a fuel system modification? I know these are upgraded turbos, but what PSI do you think they start losing efficiency? They are technically still pretty small. And is the fuel system modification big enough to allow these turbos to stretch up to the point?

[dicostal]

Fantastic work!!! You guys need to open a shop in CT.
Enrico you are ready to upgrade?

[enrita]

Originally Posted by dicostal

Fantastic work!!! You guys need to open a shop in CT.
Enrico you are ready to upgrade?

always ready

[dzenno]

Upgrade what? TD stg 2 turbos = ASR = RB in terms of power/psi, just the fuel system

[Doug007]

Originally Posted by zsapphire7

I really dont think you guys get it... the reason why Hp is nearly flat for 5k+ to 7K is because torque drops off. Im just asking what the limitation is thats causing this.

And no, tq doesnt always drop off at the top end. Just look at the m3 dynos. I used to think it dropped off for the n54 because boost tapers on stock turbos, and obviously theyre too small so efficiency dies off or not enough fuel to support the top end. But now that those issues have been resolved, there must be another bottleneck.

The limitation is the air/exhaust flow through the engine, especially the heads. As rpm increases under WOT the mass air flow will increase and the losses will also increase.

That's why M3s have much less torque drop of than a 335i (much better heads/air flow through the engine). However, all cars will eventually have a drop off in torque due to the physics of air flow.

Take a look at this dyno comparison of a GTR and Lexus LFA: http://www.motortrend.com/roadtests/.../photo_13.html

Even the LFA with a very good breathing naturally aspirated engine has a torque drop off. But, incredibly, it's not until after 7000rpm!

[Mark313]

Finally some big numbers on pump+meth. This would be a beast for a daily driver. Nice work, I can't wait to see higher boost + race gas.

[lamia2super]

Originally Posted by dzenno

Upgrade what? TD stg 2 turbos = ASR = RB in terms of power/psi, just the fuel system

??? ASR and RB are very different

you are right about the fuel issue tho

very nice shiv! how is your meth setup?(jetting) one m10? or 2 m7s?

[wren57]

Have you cleaned out the valves? I bet that would put it over the 500whp mark if not.

[OpenFlash]

Originally Posted by wren57

Have you cleaned out the valves? I bet that would put it over the 500whp mark if not.

I haven't even checked the valves. I suspect there may be some carbon build up given the high mileage (80k). I will likely take the off the intake manifold and clean the valves this weekend before I go for a high boost/max power dyno session. Today's exercise was simply to get a realistic and perfectly STABLE street tune (no race gas), not to break any records. I made 530whp out of one of these turbos a couple years back in Floriday so I already know what it's capable of when running a more aggressive tune (20psi, race gas, lots of meth, etc,.)

[wren57]

If you would, after you clean the valves please do a dyno pull or two with the same settings as this dyno run. Would be interesting to see how much power the carbon robs.

Y'all are doing great things over at Vishnu, keep up the good work!

[Ilma]

Those have got to be the best looking dyno plots and datalogs I have ever seen on this forum.

[Dmacc]

Glad to see you got your kit!

Those numbers are way too sexy for 91 octane and meth.

I need me some upgraded turbos and that fueling system!

[dzenno]

Originally Posted by lamia2super

??? ASR and RB are very different

you are right about the fuel issue tho

very nice shiv! how is your meth setup?(jetting) one m10? or 2 m7s?

Oh yeah? what's different in terms of power/cfm/psi?

Actuators are different but that has nothing to do with power/cfm/psi...

I guess what I'm trying to say is that among those 3 turbos power delivered will be VEEY similar if not the same

[lamia2super]

Originally Posted by dzenno

Oh yeah? what's different in terms of power/cfm/psi?

Actuators are different but that has nothing to do with power/cfm/psi...

I guess what I'm trying to say is that among those 3 turbos power delivered will be VEEY similar if not the same

ASR is a char upgrade and has proven to make 20-30hp more

[dzenno]

Originally Posted by lamia2super

ASR is a char upgrade and has proven to make 20-30hp more

Which 20-30hp proof are you talking about? If you're talking 20-21psi runs shiv did a few years back than you're wrong as we haven't dynoed at 20-21psi with any turbos yet due to fuel...Given everything the same all 3 of these turbos will yield virtually the same peak numbers...

[mithiral67]

Originally Posted by dzenno

LOL Who told you that? Soon you'll find out this motor held A LOT more than that stock internals, with the "proper" fueling

Stock, these cars have a limit, its why aftermarket parts exist.

Its going to take a lot of changes to push these engines to a 600ish whp. Something currently no one has done.