The boost pill is a smaller size than stock. The turbo has to work harder to generate more boost to overcome the resistance of the smaller hole in the pill. A larger hole in the pill will bring down the boost.

 

Looking at the chart peak stock tq was achieved at ~3500 rpm. The peak tq for the 3076 was achieved at ~4600 rpm. That is 1100 rpm later than stock. That would have an impact on daily driving.

What would the peak tq rpm be with the 3071?

 

It's not about comparing peak torque, look at both curves at the same rpm. at ~3500rpm the stock turbo peaks at ~270 ft/lbs. The 3076R does spool slightly slower, but matches ~270 ft/lbs at 3500rpm like the stock turbo, and the torque just keeps climbing from there.

That's not too bad, but I also agree with you, I'd like to see how the 3071R spools and how much power it's capable of.

 

Peak torque is significantly later, but the 3076 hits the ~210 lb-ft roughly 500rpm after the stock turbo. I choose this point as it's when both turbos are spooling and it's easy to read on the graph

The 3076 matches the stock torque at ~3500 rpms. So anywhere above 3500, you're making more power. Not too bad.

 

This is just the first chart try not to over-analyze it. It is just one example of this turbo on one car. Who knows what power/spool characteristics tuners are going to be able to get once they have mroe experience tuning it.

 

Then why does cobb require you to take out the boost pill in order to run stage 2 boost levels?

 

because the pill cobb has you remove is a DIFFERENT PILL than what he is talking about

 

different pill.

^^crap, got beat to the submit button

 

actually the Pill is a restrictor so that the WG sees less boost pressure therefore increasing the boost!

 

My bad. Just trying to understand everything.

 

As I said to start with this was a bone stock actuator . Had we fitted the 1.4 bar uprated units we have , 500/525hp would of been a very easy target , this car has had 6 visits to the dyno with many stages of tune with lots of new development parts ,the garrett is a stunning modification to upgrade too !. Turbo speeds show us the turbo is just cruzing in real terms ,the fact 1.6 bar yeilds 480hp is just a small incited to the 4B's power making potential .

 

Somehow I told you so wouldn't work!



Garrett did there job perfectly, if you want 30 psi at 8500 you wanta 35r, not a 30R. Making a 30R evox friendly was about making it fit, given the constrictions of space, inlet, and outlet, and they did it very well.



Scorke

 

Back in the day when the Vishnu staged kits were the rage, you could opt for spec'd GT3071R and GT3076R. But they were external gated.

I had a 3071, and most everyone else had a 3076. The power on pump gas was identical, about ~350whp uncorrected Dyno Dynamics, good for high 11s and about 117mph trap speeds in a CT9A car. But the 3071 spooled about 300rpm faster. I think the 3071 is superior for autocross and pump gas.

The 3076 made about 10-15whp more on race gas, but it sustained the power MUCH better in the high RPM. Once it hit peak power, it carried it clear over to the rev limiter.

A 3076 on race gas in a CT9A making around 420whp on a Dyno Dynamics is a low eleven second car that will trap 125mph. These are awesome for bigger tracks and roadcourses.

Sorry for using some drag racing analogies too, but it gives you an idea of power.

Sadly, these Evo Xs are 300 pounds heavier, and have nowhere near tall enough 4th to see 120mph trap speeds.

 

Just remember that the 300 rpm difference in boost threshold (more correct then "spool") is on a dyno in 3rd or 4th gear.

On the street in 2nd gear both turbos will boost later in the rpm range, and the difference in boost threshold will be greater (like 600 rpm in 2nd gear, maybe 1000 rpm in 1st).

This is after much experience with road dynos done in different gears.

Not saying the 3076 doesn't perform great, or "spool" really well, it definitely appears to, just trying to inject some slightly better info.

 

That all depends on the load on the car, if you want to split hairs... driving up hill, down hill, passengers in the car, etc...