earl3

That's not good! Thrust bearing failure?

pete95zhn

Question's in the pic...and if the answer is yes, no wonder the compressor starts to chew it's housing...there's some serious unbalance. Fortunately missing pieces will be catched by the IC. Which needs thorough rinsing.

TB993tt

Yes cracked blade, it happened during full boost acceleration in 4th, theory is that it blew the hose (the hose was torn) and it overspun the wheel causing the damage to the blade.
No sign of any debris, we think it vaporised

pete95zhn

Or the blade, while been spinning about 160k rpm shot through the hose after being separated from the wheel....

TB993tt

Update.

So "my" understanding of the VTG engine and what "the ultimate VTG engine" means is developing as I learn more.

We know that it is the heat created by the VTG turbos which is what causes the problems for making more power.

It is as much the heat created by the VTGs producing the maximum boost (and torque) from very low revs ~2000 all the way up the rev band which causes the extreme temperatures (as much as the headline high boost number)

I think I was a little confused when we had the limited input from the Champion MS guy on here since I thought we were discussing the same sort of torque curves and engine charactaristics since on his thread he states:

. Maintaining low end power will be key to staying competitive

But as always it is in the interpretation of the words, so in this instance as we saw from the only data available (the 4th gear pull) the full boost comes in at 3600rpm, so this is what they consider "low end" compared to what I/my tuner consider low end which is what the factory did with VTgs so low 2000rpm level.

This is quite important when we try and compare VTG engines......

The Alzen 1054PS Mission 400kph car apparently had the exact same turbos as mine (above) but with a bigger outlet on the compressor side. Mine measured at 49mm (not sure whether this was the inner or out flange part) and the 1054PS car VTGs are only slightly bigger, maybe 2mm or so.


One reason the Mission 400 engine could make its power is that the VTG is deactivated and the vanes run open all the time just like a big normal turbo.

This obviously makes one reflect on these 68mm VTGs which clearly have bigger compressor housings and with their limited low end boost it seems likely that the 2200kg/hr they are flowing may well translate into very high power levels - so my dogmatic statement about 700hp being the maximum for VTGs is incorrect, apologies to all those insulted for that one

The reason I became very interested in this was we discussed putting the Mission 400 turbos on my car but RS did not want to as he said it will move the boost higher up and it will not be a nice car to drive and defeats the objectives of the VTG system.

What I was quite fascinated about and pertinent to the previous turbo discussions was that the actual VTG units were deemed superior (than the old K24) to the non VTG units even when used in fixed vane mode.

I had already decided that I wanted to lower the torque number from the 920NM at 3000rpm since on the GT2 in anything lower than 4th gear it was simply too much and second gear was pointless with the TC flashing at all times.
I had previously had my diff rebuilt and it was showing signs of extreme stress and I know that the gearbox also would be starting to complain and I really am not wanting a $$$$ gearbox rebuild.

So as the discussion headed this way it also covered my misfire which was basically described as too high air mass (in sub 10degC ambient) triggering the torque limiters as the boost overshoots as it ramps up at 2500-3000rpm, (now they had the car they could easily fix it if I would have wanted) it was suggested that I have the cylinder head prep which they did for the Mission 400 engine which involved bigger valves and he would calculate some specific camshafts which would physically lessen the low end torque but provide better breathing at the mid and top end so they could run the same boost with more efficiency (less heat).

How low to keep the torque is something I am pondering on, Porsche seem to think 700NM is the correct number, even kept the RS there, but I am thinking maybe 825 to 850NM ?

We also discussed a few other "tweaks" like exhaust bypass straight from turbo to atmosphere and bigger Motorsport intake manifold but my budget was already overspent !

So my broken turbo will be fixed, engine "kontrolled" , new heads and cams then a new program with a lower torque build up will be done with maybe a few more peak hp.

Roll on 2013

earl3

The champion VTGs have a 49mm inducer (same diameter as yours above but with 7 leading blades) and a 68mm exducer, and you're right they do run a custom compressor housing. You can measure your exducer once you pull the compressor housing off, which I'm very curious to know!

Interesting stuff on the Alzen car!

jparker36

This is a HTA wheel from forced performance. They are very close to me, and I was just there on a different matter, and asked if they sold their wheels to champion. Yes, they do. So there's that.

The HTA wheels are used heavily in the import tuning world, because they provide spool, response, and power levels no other turbo can match. The new garrett GTX series is ~10% worse, the new BW wheels about the same. FP is a small shop, but they have flatly beaten the big boys.

I 100% believe the numbers champion quotes, as I've seen a single one of their hta86 turbos put down 800+ on a 2.0L Mitsubishi. Two slightly smaller versions on the Porsche should be able to make the claimed numbers, though the spool won't be 2k rpms for sure.

TB993tt

little update on the 2013 Ultimate VTG build

Engine was fitted with new turbo and tested on the dyno pre any work.

They couldn't replicate my misfire/overboost issue but this isn't a surprise since it didn't happen before on the engine dyno either, just on the road in certain conditions.
The good news is that the full power pulls indicated an engine in the same health as when it left the shop some 15K miles ago which my wallet is pleased about.

Wallet is not quite so happy about what the boss decided he wanted to "try" on my engine.....

This car below is a race 996 GT2 which runs a 3.9 engine like mine but without VTG actuation, has the ported big valve heads and special cams, it runs Bosch MS 4 engine management and makes over 800PS whilst running very high CR which apparently makes it mega torquey "like a 10 litre"



Anyway notice the intake manifold, it is the one below, a 997 GT3 unit. I understand (not from RS) that the runners on the GT3 are over 20% bigger than the 997 turbo unit which with a ported breathing head means more top end power.

AFAIK this manifold has never been made to work with 997 GT2 factory ECU and TC/PSM systems so this will be a first (if it works)

TTurbine

Sounds Great Toby, Ported GT3 Manifold should show some good gains on a turbo engine , Manthey and Im sure RS does port these GT3 Manifolds on there engine builds, Maybe you can lure them to do the same on your car along with the heads cams and bigger valves this will be one stout package.. Interesting that the VTG vanes can be deactivated ....

On the other hand any news on there new 670ps VTG turbos?

Rickard 993 Turbo

Both evo ms and other in the USA use those manifold on 997 turbos and gt2

TB993tt

with all original electronics and safeguards working - I don't think so ?

TB993tt

I guess they just fix the vanes in a certain position and run them at fixed boost levels using the Bosch MS 4

I didn't ask sorry

Nick Wong

I see Toby and RS Tuning finally decided to enter the 21st century. It only took 12 years more than the natural timeline.

1. Without a larger housing, the compressor wheel benefit is limited. There will be flow and temperature issues and efficiency will be compromised. It can sort of work, but it's not optimal.

2. VTG vanes can be fully controlled by the ECM. That means they can be fully opened, fully closed, or anywhere in between. If your tuner can't control the vanes properly, get another tuner.

3. If your tuner is competent none of the OE engine tune safeties should have been affected. No broken intake manifolds, etc.

4. Above approximately 700whp even a rescaled big tube MAF will max out. The US tuners that I consider to be reputable do not use MAF at that power level and switch to MAP.

5. GT2 intake manifolds are out of efficiency before the Champion 68mm VTGs really get going. Stick with the GT2 manifolds, expect to have lower power output and more intake tract stress.

5. Call Champion, talk to Tom, and get the information direct about the 68mm Champion VTG billet housing upgrades. No amount of forum searching will divulge that info from VFBs or FFFs because, quite frankly, they don't know.

RS38

whop??

Stock(!) MAFs on stock intake pipings work well till 2100kg/h which is still fine for 700WHP!!
rescaled MAF on bigger tubes of course work with 800++ WHP.

many tweaks are due some limitation to handle boosts above 1.6bar, but I do not see any reason to remove the orignal ECU??

Nick Wong

We are at the limit on a bigger tube MAF on my 93 octane ECM program. That is about 720 to 750whp, give or take. On my 114 octane ECM we are MAFless (MAP only). Even on the low boost map on the 114 octane ECM we are well above the threshold of 5v. We chose not to go with an even bigger tube MAF because I wanted low boost 93 octane use and drivability too, so a big tube MAF, while gaining resolution under high flow, would lose resolution under lower flow. I only use the race fuel ECM on track, the car has plenty for the street on street fuel and has good street manners in that state of tune.

There are some proprietary tweaks in the Champion/GIAC tune- how they map the boost (my car is well over 1.6bar on high boost and 114 octane), how they map the ignition, what MAP sensor they use, etc. All factory safeties are in place.

It should be considered- if we are flowing more air, we are making more power, assuming similar BSFC, and we are flowing a lot of air at 750whp, or at my base tune in the 114 octane ECM. The switch is simple- swap the harness over, and detach the MAF sensors under the hood. I don't even kill the battery.

I agree, the OEM ECM is very good, it just needs to be tuned right. No need for others, some people like using Pro-EFI if they go away from VTG and/or use E85 with the GM sensor. I think Switzer does that, and apparently they are very successful doing those conversions.