Bimmerboost Exclusive - ASR Engineering 135i on the dyno

[shiv@vishnu]

Ah yes, those videos bring back memories. Namely, drenched in my own sweat on a humid summer day in Florida. It's funny how the car gets all the cooling. But not the n00b behind the steering wheel

[Got PSI]

Ah yes, those videos bring back memories. Namely, drenched in my own sweat on a humid summer day in Florida. It's funny how the car gets all the cooling. But not the n00b behind the steering wheel

You can say that again! I remember how hot it was at the dyno! Good times though.

Thanks for joining the site! Glad to have you on board!

[shiv@vishnu]

Thanks man.. glad to be here. Nice avatar!

[fundahl]

Thanks for posting the videos Got PSI!

Blk135, the stock fuel system just does not have the capability to safely support 500whp on pump gas. Therefore, 100 octane was used to take advantage of it's slower burning properties and meth for the additional fueling.

SlicktopTTZ, the torque drop in the upper RPM in our opinion is not bad at all and does not have a direct relation to CFM ratings of these turbos. However, the machined stock turbine with our Garrett CHRA housing do have a limitation as far as exhaust flow and turbine backpressure. This would cause the torque curve to drop sooner than it would with the correct turbine housing the CHRA is designed for, but only once it's reached it point of diminishing return. These turbos are rated at 26lbs/min or 376.22 CFM per turbo. That being said, the turbos can support the hp shown above very consistantly. If in fact we were running out of CFM, this would show considerable losses in hp at the upper rpm band as well. Torque plays a major roll in overall bottom end acceleration since it is defined as the turning force, but is not even a factor to be mentioned once the vehicle is in the upper rpms band and has already picked up speed. Horsepower, on the other hand, plays a very important roll in acceleration at higher speeds. This is why F1 vehicles have such great top end power, while having very little torque due to their small displacement.

Well, F1 cars also make peak torque close to redline. What I'm trying to say is that we are losing horsepower by not having as much high-rpm torque. When I drive my car and shift at redline my next gear will land at what, 5,000 RPM at lowest? I do not care much about anything below that. Also, holding a flat torque curve till redline will equate to more horsepower than having the same peak torque much lower in the powerband and then it tapering off as you rev out, as I'm sure you know. I understand the housing is tiny and a limitation, and I am saying that these turbos still are showing a considerable hp loss which would not be the case if they held that 467ftlbs till redline instead of tapering to around 350ftlbs by the time I shift. Once again, I'm not saying this isn't a good option, and I congratulate you guys for the engineering to make this happen, but I guess I'm looking for a setup that is even less restrictive, unless you guys can get something to fit in the stock housing (or an entirely different turbo) that will support more torque up top. Here is an example of what I consider a flat torque curve near redline:
I understand that this ^ turbo system is laggier, but it also on a much smaller, less sophisticated, lower compression engine, the SR20DET.

[onesuperboi]

I like the results a lot. Look how much more hp there is until red line. That's worth an upgrade.

[GTR-Dad]

Torque plays a major roll in overall bottom end acceleration since it is defined as the turning force, but is not even a factor to be mentioned once the vehicle is in the upper rpms band and has already picked up speed. Horsepower, on the other hand, plays a very important roll in acceleration at higher speeds. This is why F1 vehicles have such great top end power, while having very little torque due to their small displacement.

Great job putting down some decent numbers!

At the risk of starting a torque/horsepower debate, I'll say that horsepower and torque are related by rpm and a constant. (Hp=Tq*rpm/5252) If the component(s) that restrict airflow above 5k rpm can be opened up you'll see less drop in torque and even more horsepower.

Great work, but don't be shy about identifying airflow bottlenecks and derestricting the system!

Dan

[LostMarine]

isnt that because HP is just a calculated # from Tq?

[Sticky]

isnt that because HP is just a calculated # from Tq?

Well yes, but multiplied with RPM.

Abid is more than familiar with the formula, basic stuff. The main issue there is getting the torque to not fall off a cliff. As in, to look as beautiful as the M3's curve

[oddjob2021]

impossible on the n54, but what we can do is make it so hp does not taper off at high rpm, instead plateaus as torque drops. you just need the right set of chra's.

[GTR-Dad]

impossible on the n54...

Difficult maybe, but not impossible. Impossible... is nothing!
Intake, exhaust, cams, fueling, turbos, head porting, and tuning - all correctly done - will do the trick. Torque peak may fall between 5k-6k rpm and begin to drop off, but it doesn't need to drop as sharply as the posted dyno result.

To be clear, I'm very impressed with the posted result, but do not accept that torque at the top end isn't valuable or that reducing the magnitude of the torque falloff at the top end is impossible.

For reference, here's an (AWD hub) dyno curve for a 2.6 litre I6 at 17.5 psi on pump gas. All the stuff I mentioned has been done on this one, and yes, the torque still drops off, but look at the slope of the power curve.


If this is too OT for this thread, pls feel free to edit my post.

Cheers,
Dan

[fundahl]

Difficult maybe, but not impossible. Impossible... is nothing!
Intake, exhaust, cams, fueling, turbos, head porting, and tuning - all correctly done - will do the trick. Torque peak may fall between 5k-6k rpm and begin to drop off, but it doesn't need to drop as sharply as the posted dyno result.

To be clear, I'm very impressed with the posted result, but do not accept that torque at the top end isn't valuable or that reducing the magnitude of the torque falloff at the top end is impossible.

For reference, here's an (AWD hub) dyno curve for a 2.6 litre I6 at 17.5 psi on pump gas. All the stuff I mentioned has been done on this one, and yes, the torque still drops off, but look at the slope of the power curve.


If this is too OT for this thread, pls feel free to edit my post.

Cheers,
Dan

RB26?

[GTR-Dad]

RB26?

Yes. This is approaching the limit on pump gas, but illustrates what's possible with 26/30ths of the displacement on a 20 year old engine design.
d

[LostMarine]

as I said before,

Holding the HP is not impossible, its all in the tune

MAXPSI Mustang Dyno:

Notice how flat the tq curve is until the taper, but HP remains the same