Ultimate VTG engines
#241
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Considering a 997 turbo's VGT maps there's still some 30% of vane opening left at 1.5 Bar... Without external device no-one really know how much boost there really was and the explosion of intake plenum is not surprising. For this external device I can recommend Race Technology DL-1 with CAN OBD interface and Dash 3 display. Fully configurable and much faster sample rate than Durametric. For accurate boost readings you also need a proper pressure sensor like the one they sell on their web pages. Bosch unit up to 2.5 bar absolute.
OTH datalog at post# 179 shows stable and correct boost with nice delta OAT/IAT and reasonable EGT. At least when compared to that one log mentioned before. Unfortunately I did not find any mention about 997's Motronic's IAT limits, but IIRC in 996 turbo Motronic starts to pull timing when IAT is above 55C..
On Earl's post (#207) there's also a maxed out HFM (4.78V) with rather high airflow reading (2163 kg/hr). If this is correct (from different HFM units and re-scaled program) it's about 750 crankhp. delta OAT/IAT is amazingly/suspiciously low, EGT on the low side too and lambda is nice around 0.8-0.83 ( both sides of 12.0:1).
Then this project of installing and programming a turbo's Motronic to a GT2 instead of re-programming GT2's one.Outsider could think that switching from expansion manifold to an ordinary one just requires adapting old maps to changed IATs and effective boost pressure without inventing the wheel again and banging one's head to "how to switch from full PSM to SC/TC" wall...because that part of Motronic's files is heavily protected. I really do hope that you didn't have to pay for all of that time they spent with the programmming.
I paid the price in how long my car was off the road !
#242
There could of been errors in air mass calculations due to turbo intake and variocam at these RPMs - resulting in too advanced timing / too lean. It's pretty clear that intake runners got blown from backfire (the cause of that could be overboost which in itself could be due to incorrect ignition/boost tables or because of VTG control problems).
#243
Former Vendor
Post #82 and some others after that.
True.
#244
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I detailed my misfire problem in case someone else had the same, I like to present tuning results warts and all, I never promised any solution.
I correspond with many Porsche owners who seem to be able to live with my "attitude" and have done on forums for many years
#245
I am using different (better apparently) plugs that sportec recommended. Still, shifting at 7,800 (limiter) takes its toll especially when its 30 degrees+ ambient. No 20k miles interval for plugs for my car!
Anyway every tuning method has different pro and cons. Toby's seems to have the best response of any modded car of that power -or even lower- that I ve seen & huge torque in the mid end. Mine has a higher red line but boosts at a bit higher rpm and seems very reliable. Response is impressive between 6-8k rpm (like a 3rd turbo kicks in) but torque is a bit flatter between 5.-6k rpm. It is also very fuel dependent as with ignition timing of 23-25 at high rpm you cant have fuel below euro 98 oct pump or impure fuel of any kind. (common in a few european countries these days). So there is no 1 size fits all really.
I seem to have had -with my previous tune- this sort of cutoff/hesitation that Toby described when torque is building up. Spent over a year and $$ trying to find where it was coming from. At the end we thought it was just a back pressure limitation of the stock cylinder heads for this kind of torque and ended up opening the engine..
Only to find out that it was an electronic limiter which i was told is a function of load/ rpm/ torque etc that was breached under certain conditions. So it was solved at the end with software alteration. I think i read something like that in the long post above from the technical manual.
I share the same experience with Toby regarding getting information from European tuners..
Anyway every tuning method has different pro and cons. Toby's seems to have the best response of any modded car of that power -or even lower- that I ve seen & huge torque in the mid end. Mine has a higher red line but boosts at a bit higher rpm and seems very reliable. Response is impressive between 6-8k rpm (like a 3rd turbo kicks in) but torque is a bit flatter between 5.-6k rpm. It is also very fuel dependent as with ignition timing of 23-25 at high rpm you cant have fuel below euro 98 oct pump or impure fuel of any kind. (common in a few european countries these days). So there is no 1 size fits all really.
I seem to have had -with my previous tune- this sort of cutoff/hesitation that Toby described when torque is building up. Spent over a year and $$ trying to find where it was coming from. At the end we thought it was just a back pressure limitation of the stock cylinder heads for this kind of torque and ended up opening the engine..
Only to find out that it was an electronic limiter which i was told is a function of load/ rpm/ torque etc that was breached under certain conditions. So it was solved at the end with software alteration. I think i read something like that in the long post above from the technical manual.
I share the same experience with Toby regarding getting information from European tuners..
#246
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Here is a little extract of a log I grabbed to illustrate boost response for my Ultimate VTG engine.
0.49s from no boost to full boost in 4th gear - gives you fellow geeks something to compare, even those of you with late boosting VTGs can test your boost response
0.49s from no boost to full boost in 4th gear - gives you fellow geeks something to compare, even those of you with late boosting VTGs can test your boost response
#247
997's stock HFM can properly read air mass up to (1060 kg/h * 2,3%) *2 = 2168 kg/h where they are capped.
Stock Diagnosis will recognize short cup at 2000 kh/h or 1060kg each.
#248
Former Vendor
EDIT: MAF's part number is: PORSCHE 997 606 125 00 / BOSCH 0 280 218 192. While I didn't find an exact datasheet for that, here's data for similar Bosch HFM in different sizes. See HFM 5 for flow/voltage comparison. OEM MAF ID is 73mm...
Last edited by pete95zhn; 10-06-2012 at 01:24 PM.
#249
I do not complain. But I do not rely on information which I did not re-check myself inside the ECU
the public data sheets of Bosch HFMs also do not cover the HFM5 from the 996 turbos.
the public data sheets of Bosch HFMs also do not cover the HFM5 from the 996 turbos.
#250
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I have known for some months that RS have been developing a new VTG turbo with the aim of lowering IATs enough that they can offer good ~670PS power without the need for their proprietry Secan intercoolers which at 15K Euro a set put off most punters.
Just so happens that yesterday after a high speed run one of my turbos started making some scary noises when trying to produce boost, sounded like a Police siren when it happened and scared the cr*p out of me ) so I am scheduled for a visit to RS in a couple of weeks for a full engine refresh and installation of these new VTG blowers and an engine dyno mapping session.
To get my car the 1000 miles to Bavaria RS are sending me a single VTG unit to "get me there", they won't send me the new development units since apparently they won't bolt on to my current set up as they have a bigger openings (this is what I understood but TBH the language barrier makes it very difficult - suffice to say they are sending me a smaller VTG to stick on so I can make the journey).
So the first thing of interest is when I get the current 740PS units off I hope to be able to get the mechanic to take off the comp housing (is this easy ?) and I will get a measurement and photo of their super duper unique compressor wheel - remember they are "apparently a design made for them from a sponsored university student" - will be fun to hear peoples views
Will be fun to compare to this
These are photos posted by Pete after Earl outed the Champion 68mm units as having these wheels - do we have any more info on this, is it fact or speculation ?
So hopefully Ultimate VTG engine mark 2 is in the making
Just so happens that yesterday after a high speed run one of my turbos started making some scary noises when trying to produce boost, sounded like a Police siren when it happened and scared the cr*p out of me ) so I am scheduled for a visit to RS in a couple of weeks for a full engine refresh and installation of these new VTG blowers and an engine dyno mapping session.
To get my car the 1000 miles to Bavaria RS are sending me a single VTG unit to "get me there", they won't send me the new development units since apparently they won't bolt on to my current set up as they have a bigger openings (this is what I understood but TBH the language barrier makes it very difficult - suffice to say they are sending me a smaller VTG to stick on so I can make the journey).
So the first thing of interest is when I get the current 740PS units off I hope to be able to get the mechanic to take off the comp housing (is this easy ?) and I will get a measurement and photo of their super duper unique compressor wheel - remember they are "apparently a design made for them from a sponsored university student" - will be fun to hear peoples views
Will be fun to compare to this
These are photos posted by Pete after Earl outed the Champion 68mm units as having these wheels - do we have any more info on this, is it fact or speculation ?
So hopefully Ultimate VTG engine mark 2 is in the making
#252
I guess the outer diameter is more like 66mm than 68mm (-> see it's not right aligning...)
Will be a kind of drawback considering spooling I guess.
original compressor wheels are ~55mm and quite tiny which is part of the reason why they build up boost very fast.
What is the inner diameter of that wheel?
Will be a kind of drawback considering spooling I guess.
original compressor wheels are ~55mm and quite tiny which is part of the reason why they build up boost very fast.
What is the inner diameter of that wheel?
#253