My latest chiptuning. Full report

[Pisobiker]

Received latest version of Mihnea chipset, last week. I then went through a weekend of full testing (while you guys where at Castle Combe). Now I think my data, meanwhile collected, maight be usefull for someone else who's looking for similar upgrades and performance targets.

My mechanical upgrade setup so far:

1. RS2 turbocharger;
2. RS2 exhaust manifold;
3. RS2 IC;
4. RS2 MAF;
5. RS2 "green" injectors;
6. RS2 exhaust cam;
7. RS2 ECU;
8. Custom 3" S.S. turbo back exhaust system with racing catalitic converter;
9. K&N panel air filter.

Engine type: ABY
Fuel normally available here: 95 ron


My previous chipset was a 340 Hp, which I've tested again together with the original ADU chips, for having the widest range of data to compare with.
Following are figures I got from testing.
All readings are "on the road at wheel", thus meaning aerodynamical drag must be taken into account if eventually comparing with a RR at wheel output.

First jpg is a comparison chart for ADU vs. 340hp vs. Mihnea chipset. Using original WG spring 3mm winded
Tables showing "Reaction time" and acceleration times aren't of course significant, being the test not meant as a "quarter mile" acceleration test (see box bottom right of jpg to see rpm behaviour through gear shift).

P.S. Power expressed in KW, torque in Nm.
Sorry for picture quality, but couldn't find a better way for them to stay whitin the 100k!

[Pisobiker]

Following is comparison run between ADU (original WG spring, 3mm winded) vs. Mihnea chipset (original WG spring, 6mm winded) vs. Mihnea chipset (original WG spring 3mm winded) vs. Mihnea chipset with stiffer WG spring (provided by Mihnea).
Latter setup gave an impressive kick on peak boost, then decreasing more than with the original WG spring. When making a run again with same setup but not letting boost peak that much (giving WOT only after 5k rpm) output on higher rpm exactly matched the "red curve" one. Only reason I can guess is a sort of "engine protection" that came out probably because of too high boost+advance compared to quality of available fuel.

[Pisobiker]

Next are torque and power figures of the two main setups. On these ones I've added some (roughly) calculated mechanical+aerodynamical drag, trying to get close to a real "at the flywheel" performance.

P.S. torque, on those, is expressed in Kgm

[Pisobiker]

and Hp

[Pisobiker]

My impressions:

- Car pulls very smoothly from idle on.
- Feeling is of significantly better responce in the low rpm (much better compared to original ADU).
- Boost threshold is significantly lower, compared to original ADU.
- Compared to my previous 340 hp setup (and apart from using the stiffer spring) engine pulls slightly better in the peak torque range, but expecially holds boost and pull much more consistently till redline (over 40Hp at wheels higher than ADU @ 7000 rpm).
- Fuel consumption also seems significantly optimized in average all around driving (and I don't mean "turtle cruising" ): gone from ~14.2 liters x 100km (ADU), to ~13.2 for the 340hp, to the actual ~12.8.

My conclusions:

Need to find a "Shell V-Power" pump close to my house. With the claimed 100 RON I'll definitly try with the stiffer WG spring again !

Nice job Mihnea !


Marco

[S2central.net]

@Marco - was that done on a whizzy s/w package of some kind or a dyno ?

Cheers,

Paul

[Pisobiker]

All the readings where taken with my G-tech Pro Competition acceleromiter.
The two jpgs coming out of an Excell file, are just done by me using G-Tech data for "at wheels" performances, then I added my (roughly) calculated mechanical + aerodynamical drag to compute some indicative "at the flywheel" performances.

Marco


P.S. what do you mean with "whizzy s/w package" ?

[KramRS2]

Very Good Marco!!!
Congratulations!!!



Impressive performance on 95 gas. How much boost are you using?

I’m still with problems unsolved. From the last time we talk I just put a VAG tool to try to find out what is the problem and no less than tem faults were stored. Then I changed back to stock chip.

I put to auxiliary pumps trying to solve the lean run problem, but nothing. Now, I have no fault codes, the car is running like . . . stock. But I still see only <800mV on the lambda. I know that is not the best precision tool, but I still think that is too much lean at WOT in upper revs. But, again, that is no fault codes stored.

I have two solutions that I will implement soon. Ask for Mihnea help, or put a Unichip.

Let’s see.

PS: Did you try your car against a RS4? ;-P

[Pisobiker]

Hi Mark,

I'm sorry to hear you still are struggling to optimize your RS2.
My personal advice is to have a talk with Mihnea.
As for my boost curve, I actually have to check it precysely all the way through the rpms, what I can say is that it peaks at ~1.7-1.75 bar (VDO boost gauge reading). Than holds pressure quite consistently till redline.
I'll keep an eye on this ASAP and will then post my readings in this thread.

Next tests will be:

- 100 RON fuel with both springs (original winded and "racing");
- 4th gear run (but woud not be easy to find a straight road long enaugh for doing a run that peaks at over 190Kmh.... and than having enaugh road left for braking )


About RS4, I've never had the chance to find one around. But I know of an Audi dealer not so far from here who has a used one for sale. If I can manage to make a road test with it .... pretending to be interested in a purchase....
I may get enaugh G-Tech data to make a good on road comparison test.


Marco

[Pisobiker]

I forgot to say that with the stiffer spring boost was bumping to 1.9 :eek2:
before settling to 1.7 bar.

Marco

[Mihnea]

That should be okay with 100 octane fuel Marco, I've already seen RS2s running 2.2 peak dropping to 1.9 and holding 1.4 at redline, should be no worries..

[KramRS2]

Definitely it will be good to do this test.

I drove my car with a chip supposed to put 1,8bar peak and hold 1,5bar until redline. It put the 1,8bar peak, but fail to sustain boost, probably because something wrong with chip and the ECU lean the mixture and control the Frequency valve to 0,9bar boost at redline. I tried to find if the problem was at the wastegate, so i put a spacer in the spring (i don’t remember the with) but it put 2,2bar boost at around 4000rpm, and man... that rock!!!! Although the boost continued to drop to 0,9bar at redline. Even disconnecting any vacuum line of the wastegate, the boost doesn’t rise above the damm 0,9 bar.

We have a 103octane fuel (BR fuel – Podium Williams – from the guy dressing yellow in F1), so I think that pinging due to fuel is not the problem.

[Pisobiker]

Mark, if you disconnect pressure line coming from WGFW to WG and boost still drops that much, I would think there must definitly be something wrong with your WG or your turbine.

Unbolt WG from header and check that gate travels smoothly and closes properly. Check also contact area between gate piston and header seat. If your gate valve stem is bent or your valve just does't fully close, pressure escaping could be enaugh to allow a high drop in boost at high revs.

If not that, my only other guess is the turbine:
your turbine, for some reason, could just not deliver enaugh "power" to run cold side at desired boost level and speed.
I could even suppose that your modded cold side wheel has a so higher flow rate, compared to the original one, that just doesn't allow enaugh spinning of turbine.

Let me try to better explain my last statement:
Inlet pressure is the result of "flow" delivered by cold side (which results by it's rotational speed compared to it's design) and engine flow needs. If for example at a given engine rpm and load, engine has a volumetric capacity of lets say 5 cubic meters of flow per minute, and at that engine load cold side has enaugh speed and power to provide 10 cubic meters of charge per minute, then resulting boost will be ~1.00 bar.
If you have a higher flow cold side, same boost can be managed at a lower rotational speed of cold side, which implyes lower speed of hot side as well. But "power" delivered by hot side is porportional to it's speed, so slowing it down will produce less "driving power" for the cold side. Than, to have same "power" as before (thus same boost), exhaust pressure on turbine blades must be proportionally increased, but that might already be on its limits.

Marco

[KramRS2]

I don’t think that problem is Turbo related because in the 4-5k rpm the boost is very controllable. With original chip it put 1,4bar, with 1,8bar chip it put 1,8bar and even with those spacers it put 2,2bar. And all them with the proportional and expected thrust.

I think that its chip or ECU security related, because the engine start to lean out to misfire. Moreover, I was doing some research on kkk turbos, and I found that the biggest rotor (compressor wheel) that I could put on the original turbo is the 52mm. So it is not big enough to give the package those kind of problem.

The wastegate appeared to be ok, with free traveling, moreover being capable of hold 2,2bar at 4500rpm it should be ok for at least 1,4bar at 7000.

How much mV are your lambda showing at WOT. Mine is at 700mV level. Before I changed the lambda sensor, and tried to push the boost it showed >820mV. I don’t even if the sensor, even new, is broken.

At least, even with these problems at high rpm boost and fuel, I could manage a head to head with a Oettinger S4 that should have 340hp.

[Pisobiker]

Mark, if you unplug boost hose going to WG, there is no way ECU can manage lowering the boost. Only thing it could do is cutting ignition advance and fuel, but then I suppose engine would not run nicely and smoothly all through the rpm (I mean you should feel a sharp cut-of of power).
As I said, talk to Mihnea. If behaviour is somehow ECU related he might know.
He might also know lambda values in mV. My EGT gauge shows mixture ratios so I don't know output voltage.

Marco