wow! a red gt2! bad *** car!

 

Nice work, gentlemen! These cars are monsters, I can't wait to see your complete results.

 

We have some headers, software, and intercooler data about to be posted. Stay tuned.

For now here are some additional pictures:

 

Ooohhhh. Single can sexiness!

 

Mike, what is back pressure of your exhaust?pipes you are using looks smaller then the stock ones.
What about turbines modifications?
No one didn't pass 600Ps on Maha dyno with stock turbines in Europe till now.
What is your impression according to the longer gearbox and bigger turbines exhaust side-lag?

 

Let me chime in here for Mike.

We cut backpressure almost by half. We are producing ~3.5psi at redline with 200 cell HJS cats in place.


No.

Stock tubing diameter is ~2.5" (65mm) between the cat and muffler and also for the tailpipes. The stock muffler dumps into a central collector chamber from below and then exits out the tail pipe from above.

Pictures above are of a beta prototype. Final prototype has longer and larger tailpipes. Our final version will use 3.0" OD tubing all the way through.

I have to admit from test driving the car at different stages, the GT2 boost delivery is much quicker than the 997TT, but it is also producing much less torque down low.

This is not surprising given the size of the turbine housings and clipped turbine wheel on the GT2. It reduces backpressure, which improves spool up, but the clipped wheel shifts the powerband higher.

Given how the car is 2WD, less massive low end torque is probably not a bad thing.


Some basic specs for the archives:

Stock cats are ~600 cell per inch ceramic like the 997TT.

Stock cats are stainless steel body. Muffler inlets are off cats are stainless steel. Stock cats weigh 7.5 lbs each

Stock muffler is Ti and weighs ~10 lbs.

Tips are Ti.

Total stock system weight is 28.5 lbs.

Stock system is very quiet and a bit odd sounding.


Our total system weight will come in around 33 lbs, including cats, muffler, tailpipes, and tips.

Our system is generating about the same sound levels as stock, but with a much more aggressive tone.

 

AWE--what happened to your 997tt project car?? I heard that it went kaboom!!! Sounds really scarey!!

 

Hah! No kaboom. Just a spun rod bearing during cold start up one day. What a pain in the *** that has been getting fixed. Gotta love the rumor mill.

At least we got to do a full evaluation of the engine when apart and were really thrilled to confirm what our borescope has been telling us. Things were clean and straight. No piston crown, valve, or rod issues even after all these crazy development miles.

 

yes, everybody use hjs cats.
stock exhaust numbers are 65mm = 0.16 Bar back pressure and you reduced it half?
using modified gt2 turbines you can have easily 1,5 bar boost at 3000rpm and it's over 820Nm on maha, but you know where is the problem right?
according to the standard turbines Manthey car is running with little over 700Nm.
for me toque is more important, I also find out that my car accelerate faster with less power but higher toque compering to setup with more power and less toque.

BTW why you use kats from Europe?

 

We saw ~ 7psi at redline on the stock system, which is ~.5bar. Don't know where you got the .16bar number from. The stock cats are where all the restriction comes from.


Um, I am not sure what you are stating here?

Can you rephrase?

We've tried a lot of different cats from many different suppliers and the proprietary spec we are using from HJS is hands down the best we have seen for long term emissions compliance and no check engine light.

 

Stef from Europipe is very good with exhaust numbers, I have numbers directly from him.
Europipe 76mm exhaust reduce the back pressure to 0,12 I think is the best exhaust you can buy.

What will be the problem with 1,5bar boost at 3000rpm?
Power drop over 4950rpm (590PS) too high egt, this is the reason why the car is running with low toque at low rpm.

Of course I know that hjs is best cat company but I was absolutely sure that you have there also best cat producer.

I'm running without cats and it works best

 

Seeing how high the EGTs already are on the GT2 when stock, I would not be surprised if pushing boost that high with stock ICs and muffler would cause problems. We did not experiment with that, as we already knew that dropping backpressure always helps drop EGTs.

If I could buy an equal quality cat here in the States, I'd do it in a heartbeat. Between the currency exchange rate and freight costs, an HJS cat gets pretty expensive once it lands here.

Depends on your definition of "best". Having no CEL light on the dash and passing emissions is pretty important to most street drivers over here.

 

Todd,
As you undoubtably know a spun bearing can be a serious problem for an engine and its important to find the cause of the problem before repairing the damage.
Have you been able to tell what lead to the problem?

 

Looks to be a low oil pressure issue that we'll have to track down in the system. Oil was not fuel fouled or past its prime, so we can't blame that.

 

Subscribed. I love following development threads.

Mike, Todd.....thanks for keeping us in the loop. All the best.