Originally Posted by TurboTim

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!

Originally Posted by Hal@IP

Doug, I love the scale haha. I updated the chart, and in case anyone missed it, you can find it below.

Again, for the majority that have not dealt with big-turbo unlocked-auto setups, they look like centrifugal supercharged setups ramping to peak power because stall depends on torque. The rpm's jump to peak power and makes the pull at an almost constant rpm. That is one of the reasons autos are great for racing - you can spend most of a pass at peak power.

Originally Posted by GurgenPB

WOw!

It's even higher than I thought, full spool at 5750.. I wish we could see a full 2000-redline torque and power plot, oh well.

Not too bad for a dragster I guess. Good luck with the engine, Greg.

Just curious, did you guys ever try the Magnetti Marelli in it?

Originally Posted by __jb

In expanding your quest for vigilance on the 350z forums...

What exactly are your qualifications? I realize that you have implied a lot of knowledge in this thread, but I'm curious about the cars you have built/tuned/raced/dyno'd.

Originally Posted by Hal@IP

Doug, I love the scale haha. I updated the chart, and in case anyone missed it, you can find it below.

Again, for the majority that have not dealt with big-turbo unlocked-auto setups, they look like centrifugal supercharged setups ramping to peak power because stall depends on torque. The rpm's jump to peak power and makes the pull at an almost constant rpm. That is one of the reasons autos are great for racing - you can spend most of a pass at peak power.

Originally Posted by IIQuickSilverII

Hal:
btw....when u taking it to the track? we want videos!!

Originally Posted by GurgenPB

Unlike MANY but not ALL of those same people that "built/tuned/raced/dyno" cars, like you said, I do my homework (not implying anything about present company or the OP in this thread, just a general statement). I am a scientist and an educated consumer capable of thought, reason, and research... And if you think that my knowledge is only "implied", please go ahead and dispute/rebut anythign that I have said about turbo design in this thread. All of what I learned is available in MANY pure and applied automotove design and development literature. I just took the time over the last few months to truly learn the subject, something that is open to everyone.

Originally Posted by GurgenPB

WOw!

It's even higher than I thought, full spool at 5750.. I wish we could see a full 2000-redline torque and power plot, oh well.

Not too bad for a dragster I guess. Good luck with the engine, Greg.

Just curious, did you guys ever try the Magnetti Marelli in it?

Originally Posted by SoundPerformance

Full spool at 5750 is VERY good for this HP!! My GT55 comes on fully at 7500. This car will never be below 5750 going down the track so you should only critique the power band where the car was designed to run at. The car will only be between 2K and 5K on the return road after running the 8 second pass!!

Originally Posted by __jb

My question was genuine.

Your posts seems very condescending to me. Possibly everyone else in this thread knows you and automatically respects your opinion. I was just curious as to why you feel the need to come in and disrupt this thread about an amazing accomplishment. It made me wonder what your credentials were... so I asked.

So... Your credentials are that you've read a lot.

Originally Posted by GurgenPB

I totally see that...in fact that's precisely what you need to do for a full on drag car.

Originally Posted by SoundPerformance

Which is exactly what IP is building.

In earlier posts when you seemed critical of their turbo choice and perhaps you were not taking into consideration the purpose of this car.

I would certainly agree that a GT47 is a TERRIBLE choice of a turbo for a street driven car with this particular engine.

Originally Posted by Gurgen

Well, the reason I mentioned this is that to me, from my research, this turbo, seemed wayyy too big. And the power drop off is likely NOT from the lower manifold entirely, but from the turbine A/R choice.

Did you get the .96, 1.08, 1.23, or the 1.39 A/R exhaust housing? The reason I say this is that he exhaust/turbine side exduceer diameter+the blade-to-wall clearance together have to be considered together with the A/R of the turbine. So, you already start out with a very large exducer blade diameter, and if you pick a too high a A/R, the turbo spool will be affected, while picking too low an A/R may spool up the turbos too quickly and hit the surge line on the compressor (since the compressor is really big).

I think hte shape of your power curve has a lot to do with the above compressor/turbine choices. But, it doesn't really matter to you guys it seems since this is obviously a drag car project, not a well-balanced street car. I am not raining on your parade, that's truly incredible power that the car is making now, but was just curious of your research on the turbocharger sizing.

Originally Posted by Gman2004

This was Gurgen's very first post in this thread. Not only does he point out that he thinks this set up was made specifically for drag purposes he also gives props.

This forum can't take criticism or opinions. Anyone doing so is labeled a hater.