TB993tt

I presume you are talking about one of my logs ? if yes then why is 1.45bar the limit, surely the limit on my engine is higher ?

can you show which log you are referring to ?

the intake plenum exploding is nothing to do with the boost levels it is to do with a misfire/backfire which occurred as the boost ramps up at 2500rpm, the boost overshoots and the ignition cuts causing the problem, it is mostly fixed now.

I have the timing/boost/IAT tables for my engine, they are tuner adjustable, from memory mine start changing from optimum at 39C..... the level can be set after testing and ascertaining the conditions where the first knock is detected.
Also worth considering that programming for GT2 expansion manifold uses a lot more ignition advance. GT on here has a Sportec motor which wrings over 700hp out of the expansion manifolds and has mega ign advance and likes to eat its spark plugs at a fair rate...
the OAT/IAT delta is about right for 4 seconds of fourth gear loading, it goes up about 6 degrees with 4 seconds of low load boost which comes on at a highish 3600rpm.
I am interested in exactly what other tuner's solutions were when using the 997t manifold on the GT2, I suspect the GT2 TC/SC systems are all ditched....
I paid the price in how long my car was off the road !

avader906

Surprising that you didnt update the thread earlier with exactly what RS found out. Half the thread is around speculation of probable causes. That and your attitude Toby prevents other people from sharing with you. rgds

pete95zhn

Logs in posts #1 & 17 show steady 1.45 bar boost. As about that higher limit, IMO it should be within the limits of the sensor. The only one the eengine uses.

Post #82 and some others after that.


This boost overshooting for prolonged periods puzzle me. I can understand that with my own engine which has auxiliary unit controlling actuators as a function of RPM & boost pressure, but even that one does it just at gears 1-2 (3 in some conditions) and for 1-2 tenth of a second but not long enough to engage Motronic's safety features. WITH OEM protections that shouldn't just be possible.

I prefer that approach to tuning. Plug problem should be avoidable with suitable plugs and enhanced coils.

True.

TB993tt

You obviously haven't dealt with RS otherwise you would know they don't share technical information, the money they spent on the Bosch engineer who worked on my engine is their proprietary information.
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

GT

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..

TB993tt

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

RS38

this is not true.

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.

pete95zhn

Pls post the complaint to Factory Tech Dept. That was a copy-paste from OEM document...

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...

RS38

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.

TB993tt

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

TTurbine

Lets hope you dont get lured into something steeper

RS38

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?

TTurbine

I guess Bigger is better in that case

TB993tt

ooops......

TB993tt