TTurbine

Toby do all your plugs look the same? or is this a shot o a plug that was on one of the cylinders that misfired?

I remember on my previous RTurbo Ruf installed 1 step colder plugs.. claimed its much better than the stcok heat range..

also back in 2008 a freind of mine had one of the first 7Gt2 in our region he had one of the first tuning kits from FVD he told me that FVD supplied him with 1 step colder plugs....

TB993tt

Moe
I didn't get to see the other plugs but think they were all similar, when the manifold was holed there was all sorts of shenanigans going on for that 30 mile drive to the shop, misfiring popping, farting etc

I am pretty certain these are the same plugs as I have in my 3.8 993tt, they are ~£25 each so a twin plug 993tt plug change is pricey !
The number is R7436-9 I think they are pretty special pieces...

avader906

I thought you were a little more mechanically inclined... sorry my mistake. We've tested my kit in various conditions - including testing for compressor surge (what you naively attempt to describe) before deciding to go with it for more serious stuff.

TB993tt

I could see you were getting a little frustrated but insulting my "naive mechanical prowess" is a bit silly. I have zero mechanical background and any knowledege I have is from experience and observation and I have been observing Porsche tuning for 23 years.

You can spout all you want but I will wager you that the problem I am having is program related even if it means that the program /VTG boost control function is not working right in the higher air mass conditions, it is no probem to live with and I am still enjoying my car daily but will get it looked at next year when the new intake manifold is available - Is your engine the guinea pig for the new intake ?

Nick Wong

Avader- it is NOT compressor surge. I've owned highly tuned turbo cars for twenty years and what we are hearing is problematic boost control, probably inherent in the VTG design. You need to take some of your own advice there buddy.

avader906

Yeah - frustration and the tendency of engineering background folks to "educate" the rest of the world.... I agree with you that in your case it is programme related - I disagree in that I do think it is *only* programme related (unlike other guys who mentioned various issues with their RS 600 kits).

We are 100% focused on getting the car done for racing next year - so no interest to get involved in R&D beyond the necessary (drop the variocam). Later next year will procure stands to do the engine/DME simulation/tuning work ourselves.

avader906

Nick - I cant argue with the guy who thinkgs that diverter valves actually control the boost in VTG equipped engines....

Nick Wong

Just like I can't argue with a guy who insists that is what others are talking about.

We've talked about several things here that are issues- torque limiter, diverter valves fluttering noise, and manifolds.

I've said this countless times now- this noise may OR MAY NOT be an issue, but the interesting thing is that it is prevalent in TB's and my cars. Apparently you are not using VTG now, so how are you contributing to a better S/N ratio in this thread?

Now as far as opinions go, I'll stick with those coming from a team whose palamares include several big four post trophies from LeMans and not some anonymous keyboard jockey.

avader906

Learn to spell Le Mans buddy.

TB993tt

Whilst TT Turbine's symptoms sound the same, my engine when running 660PS with bigger VTGs and 827NM did not have the shuffling noise or any misfiring so I reckon it is these extra large compressor wheels which are causing the problem and TTs is something else ?

Whilst I have a naive and very limited mechanical knowledge I know the numbers and never before has it been possible to have 900+NM @ 3000rpm, (as you know if you read my story the engine dyno from RS Tuning broke and had to be upgraded because of this massive torque at such low rpm) and it is the physics of what is happening at this point which is causing the problem and it is the increasing air mass (due to lower ambient temps) which is making the program cut the spark....

Nick Wong

Glad to know you can stay on topic. You're on my ignore list, cheers!

tcsracing1

open cheque book.

tuning trouble is exactly why i would never go this route.

But the end result must be quite the experience!

avader906

The only similarity I can see is that you both report "hitting rev limiter" like hesitation. It could be overboost condition (map) where fuel cutoff is initiated to preserve the engine as ECU can not adapt (control) the boost. It is similar to safety-like mode with non-VTG turbos if ECU thought that wastegate was stuck.

But 2 logs you show are widely different - with TTurbine's showing ECU struggling to adapt. Without additional logging it is not possible to actually pinpoint the problem as I've mentioned. I mean it's not clear if this is the cause or the consequence.....

On my kit we never changed the plugs from OEM - because their heat range is what RS based their tuning on - and what ECU has for base parameters. So say by running colder plugs you can trick ECU to more agressive under certain conditions - and trigger faults. This is very unlikely in 18deg C weather - but every little modification could get you there (2-3psi less backpressure catless = 2-3psi more boost for the same vane angle, then add 5-6 degrees of more advance because of plugs etc... we can quickly get out of the range that ECU can adapt to based on the tune.... and show faults). This is why you tune everything together - there are so many moving parts.

In you case I honestly think that RS should chip in and refine the tune. I know how busy they are with Alzen's new toy but you are vvv good customer of theirs......

The drop in ambient temps basically increased the air mass max by 20% - and ECU should be able to adjust if base tables have no errors (note that ambient temp has no effect other than for motor fan (engine bay temp sensor - as air mass and IATs are measured directly and independently). To give you an example - on my car we played with GT3 throttle body (larger diameter) - without re-tuning base tables that are calculated for the given volume of intake tract and TB diameter - but ECU had adjusted/learned.... that's how flexible software is these days - far from linear (or lookup tables) electronic injection.

It sounds like you should not be showing full boost at that point (either because of more gradual boost set-in required, or release of boost from max via vane control at that point - ie you require less boost for same torque output.) However it does not - and prime suspect -> errors in VE/boost etc calculations.

avader906

no different at heart than adjusting carbs

TB993tt

They will put it right but as you (appear to) know they are too busy on race engines and whilst they would I'm sure take the car off me I don't want to be without the car again so will wait until they have some time.
In terms of $$$$$ good customer, just one of the 6 litre CGT engine customers (did 4 last year) spent more than I have done in total on the 5 engine builds/tunes I have had over the last 14 years, they like me cos I am a "tame" customer and believe everything I am told

The point is that the boost ramps up so violently that the current programming/set up cannot reign it in quickly enough so I am in Nicks camp that it is a combo of current program and vane control not being up to the 20+% higher air mass.