no problem with that, that wasnt the thing....

 

agreed...it would be nice if everybody got scrutinized the same way though.

and good you pointed that you were not comparing vrt to injected... that really is quit an insult

 

Having built a few 1000 horsepower cars in the past, the one thng I see that could be a reason for the power fall-off in the upper rpms is the upper intake manifold bottleneck. Greg used a big Throttlebody but if you look past the TB is reduces down to what appears to be 75mm OD which would roughly be about 68-72mm ID(depending on the thickness of aluminum). Once you have a restiction on airflow, power and efficiency will fall off. You can keep turning up the boost and you will make more peak power but the power at higher rpms will still drop-off. On the Supras we will typically run a 90mm-105mm TB and with the right turbo, they keep making power to redline.If you look at any car that makes a 1000WHP,they will typically use an 80mm TB at a minimum.

Oh and outstanding job, Greg and the guys at Injected!

 

so the upper..not the lower collector?

 

The lower collector is bigger then the 2JZ so I dont think it is the problem since there are guys making 1500WHP.

 

so the "neck" of the plenum then need to be = to size of the bigger TB???

same body needs to start making custom plenums like this with teh TB lol

 

This is true. And the converse is also equally true.

Skilled technicians (with years of experience) should not discount the insight and analysis of even green Engineers or Scientists either.

Turbos (and other complex devices) would not exist without Engineers and Scientist to invent them.

I really appreciate what Gurgen is posting here and I wish there were many more like him. Its not just bolting on a part and dynoing it to see what works, Gurgen's analysis is a logical/mathematical approach for converging on an optimum.

I place a high value on that.

Scientific analysis can do in minutes what may take "trial and error" many years (if ever).

EDIT: This was a late reply. Not meant to reiterate water under the bridge.

 

That is the deal. If you have a big TB and the piping behind it is smaller,then you are essentially reducing the size of your TB.It is about volume and pressure.Blow through a coffee straw, it requires more pressure and moves less volume then if you blow through a conventional soda straw.The same applies for turbocharging or anything that has to do with air,water or electricity.I can get all technical like Gurgen but there are alot of people that dont comprehend the technical mumbo jumbo so I like to be really basic and simple with my explanations this way everyone can understand it

 

no need... it was good as it was in the first place, i have already been looking into this already... hoping someone out there makes it

 

I am not here to debate any of this, but have a few comments. Multiple theories have been presented (some good, some not so good) and to each their own. There is still a great deal more power (both peak hp and area under the curve) left in the setup. Our intake setup is definitely a bottleneck which we have plans to fix in the future. Also something not considered is timing: NO ignition advance is being added back after peak torque as of now. For RPM reference, we are still making 970whp @ 7000rpm.

Keep in mind this is a big-turbo unlocked-auto setup - which can be challenging to dyno. Stalls are a function of torque, so as boost and rpm climb and torque is increasing, it stalls higher and higher which can give some goofy looking dyno plots. Our GT47 Supra and 9 second Lexus both look like supercharged setups on the dyno, but when run on the street/track they stall to the point of peak tractive effort and plant massive power all the way through the pull. After Friday when our Z put up 1016whp and over 65 pulls on the dyno we had to get back to work on other projects and customers.

We will be putting the Z back on the dyno before long to continue tuning for more power, but first a few loose ends must be addressed (such as needing a new driveshaft loop to accommodate the massive ds) so we can make a few shakedown passes at the track.

 

thanks for the update

keep us updated (pics/videos/etc/etc) =]

 

can we get a picture with the RPM on the dyno chart?

 

ok since i can't get an RPM answer.. based on hal's statement of 970whp @ 7000 rpms.. here is an estimated RPM plot

 

Hmm. So it makes 26# of boost and 600rwhp at 800RPM? I have a feeling we're looking at a small portion, not a 0-8000RPM, of the dyno chart. This is a big turbo, which makes me skeptical that the plot would be better than a 8L V10 TT Viper or similar...

 

Nice numbers.

 

interesting =]

thanks doug

630whp at 833 rpms?? "scale" must not be right...

hummm not fully conclusive...
lets wait for injected to post the actual rpm plot for now


thanks doug anyways hopefully they post the actual dyno sheet soon

 

No way in hell that RPM is even close...sorry

I'd estimate that that boost is really built at aroun 5000 rpm, no earlier

 

yah i think doug was just making a point about seeing no chart

 

 

I apologize for not getting back to everyone's emails, pms, and phone calls more quickly. I am out of town this week with limited internet access. I know Marty, Hal, and everyone at Injected are trying to answer questions as quicky as they can.

Again I apologize for not responding to everyone's questions as quickly as possible.

Greg
Injected Performance