With the right turbos say 2x gtx3076s

How many RPM can you turn it
How much boost can you run
what are the hp/tq limits of the bottom end.
Does anyone sell cams or perform head work reasonably ?

What threshold do you put pistons and rods in the motor?

Whats the LPH on the stock fuel pump when do you need to go bigger?

Anyone run an air to water intercooler?

Sorry i tried finding these in the knowledge base and didn't have much luck.

Thank you,
-Foo1

 

Tons of variables but look at 1.2 to 1.4 max if you have the right fueling and tune. Hp isnt the issue cylinder pressure and torque are

And yes cams and headwork are available pm me

 

So is the governing method of failure Rods getting kinky on you or heads lifting.

 

Yes rods and 12mm head studs open up 4 figure possibilities

 

Torque spikes are the bigger issue with "kinky" rods.

Later, Steve

 

What fails these engine is knock and low-rpm torque. A twin turbo setup makes a lot of torque down low. Even the GT/GTX/HTA etc 3076's will spool up and hit 1.5bar at 4-4.5k rpm. Thats enough to fail your engine over time.

I've been running over 1.6 bar for around 15k miles, and 1.5 for even longer. Just recently (About the last 5-10k) have been at 1.7bar or over. I use a PBC Pro boost controller to keep the boost in the tip-top rpm. I only let the full 1.7bar loose at 6-7k rpm. I drive the car super hard, and have done various roll racing events and track days without issue.

In my honest opinion, the reason engines fail is lack of education, lack of knock/afr monitoring, and poor driving decisions (5th-6th gear pulls from very low rpm in hot weather). If we were talking mere numbers, I would say the torque down low has to stay under 630whp. Let the hp go wild. There have been many cases of peoples engine going upwards of 800wtq before it goes, and also many cases of people losing an engine at 500whp. It all depends.

I think boost control is top priority. You can't slap a slower spooling turbo on and hope it fixes the low-end torque bump, it doesn't. It helps, yes, because the A28 and turbos alike will spool into infinity and blow your engine, but the curve of a 3076 looks identical, just moved (a bit) more upwards in the rpm range.

Heres an image of the exact same tune. Ive overlayed the two lines in photoshop (Datazap doesn't do this for me) The green line is after the boost controller was installed and set to keep the boost down until 5krpm. You can see how the purple (ECU Boost control) lets it go crazy down low. The death zone is the space between the green line and the purple. This is a HTA3073 turbo, running at 1.5 bar. Ignore the wheelspin in the log. Ha!

Note: The RPM numbers on the left axis are incorrect. These pulls were from 3.1k to 7.1k. Something happened during overlaying them. However, the number on the right (in millibar) are correct.

 

Torque is what kills the rods, hp is torque over rpm. High torque down low bends the rods, cylinder pressure is too high and they begin to bend. A trick to keep them alive is to keep boost down until past peak VE (torque peak usually) and then feed in more boost which will raise the power level. How high? How much you willing to risk an engine that can cost $20k to replace?

If you swap the rods out you might as well drop in new liners and Pistons too. No way would I go for big hp on stock liners and pistons. If you do liners and pistons you can bump displacement too and get a good 40hp or so down low. You will want heavier duty studs, 12mm is what I'll do but this will require some machining. Don't use the ARP 10mm studs they sell off the shelf, they fail.

Fuel pump? It's not real high flow but can handle over 550whp but you'll need injectors or many use a higher pressure fpr but that seems to be a bandaid. Silly Rabbit sells a nice drop-in fuel pump setup, rails, etc. which is where I'm headed.

You will need a clutch early on with even just a flash. You will also need intercoolers, I chose Silly Rabbit 4.5inch units, both for flow and cooling. Stock won't handle the heat by far.

Engine management - lots of options. Flash the ECU, use Cobb on the ECU, swap in a Syveccs, AEM Infinity, or proEFI EMS. Get high enough power and you get to worry about the transmission and axles but you're pushing 4 figures at this point.

RPMs? Not seeing any reason to go past about 7200rpm. You can pickup power in the heads for sure as OEM they're a bit rough but it's not cheap. You'll probably want to upgrade the lifters to 997 units too. A few reground cams around, not sure how much power is in them. Some ancillary things like throttle bodies and intake piping will pickup power. Choose a good exhaust, many drone and zomg it's awful. Weld or pin the coolant pipes. Consider an lsd in the rear diff.

 

if you are upping the displacement theres a few kits out there. if you are staying at 3.6 the stock setup will handle 800+ with ease. fi you want more power off boost then a 3.8 swap isnt hard to do and doesnt have to cost a small fortune

 

I had the same questions as well as of recent and I found this thread from guys at PTF:

https://www.6speedonline.com/forums/997-turbo-gt2/378971-875whp-700wtq-gtx3076-997-1-turbo-protuning-freaks.html

They have done a few of these it seems all in the same power range and are keeping them alive with very smart tuning that seems to be holding up really well. They tune with Cobb and AEM Infinity and seem to be solid. Talked to Dzenno yesterday about tuning my setup soon, solid guy all around. I am planning on a built 3.8 and will push it hard and pretty sure Dzenno will be my guy to work with on the tuning. Still trying to decide on a bunch of things including do I want an external wastegate or not. I saw the new SRM kit really awesome idea and great price but a part of me just can't stand internal wastegates period. I need my shiny flowing tested and true external gates. That's just me.

 

If I'm going to the trouble of getting that deep into the engine and doing 12mm studs with the attendant machining no way in hell am I leaving in the stock liners. The nikasil stuff is fine to a point but a good solid sleeve with new rings and pistons with a small disolacement bump seems much more prudent. Certainly added cost but when you're that deep into it I'd call it insurance!

 

you can run external on the 7163 but its ot needed. mine have new dual port internal gates good to 40 psi.

 

factory ecu doesn't have boost control as an adjustable parameter?

Sorry i had a subaru with a gtx35 that i tuned myself with cobb's access tuner race. I find it hard to believe that there isn't some PWM signal out for a 3 port boost controller or something to use.

 

Well of course there is. The problem is the factory ECU isn't as simple as just putting in some new duty parameters. Todd @ Protomotive tried many many times to pull out duty cycle from the bottom end, but he couldn't. He ended up getting it down to about 60% duty, but after that it wouldn't pull any more. He was fighting the oem boost control.

The only way to truly get that low-down spike out of the way is to go to some sort of aftermarket ecu, boost controller, or just build the engine and let it take the hit.

But I should have been more clear in general. There is a PWM controlling the wastegates on the oem ecu, it just doesn't respond fast enough and is too hard to fine-tune.