Engine build questions

[ThatGUY]

I am in the process of building an AAN motor. The block needs to be bored 1 maybe 2 oversized. I'm going to order some JE pistons in the next few days.

My question is; if I plan on running full RS2 spec and have a remap by Mihnea (trying to achieve 250-280hp and as close to 600nm as possible) could this be done on the standard compression ratio or would it be best to lower it a tad?

Also what should I do about piston rings? Should I get an after market set that is setup the same as stoandard?

I would prefer to keep it standard, If I should lower it how much shorter does the piston need to be?

Thanx
Andrew

[AnLe]

Well, I had 577nm with 48/55 (rs2 cold side and k26 #6 hotside)
nm ex cam
3inch pipe but orginal downpipe, no pets
custon software

(unopened 3b 200k km paper gasget, org exmanifold and ic)

All this used the orginal wgfv.. Car runned fine but even better when removing it.

[ThatGUY]

Thanx AnLe.

I will order the standard compression ratio.

Andrew

[Mihnea]

Andrew, after tuning many cars on US gas, I'd go for slightly lower CR than 9.3:1. IMHO 8.5:1>9:1 will be fine and you won't need to run Shell 93 octane to avoid pinging (Mobil 93 octane is not the same as Shell 93 octane on the east coast at least)...

@Antti: That dyno graph means 1 thing to me: too much boost and backpressure at low RPMs, that's what prevents your power from going up above 4000 RPM. Slightly less boost at peak torque RPM would have given you around 550Nm but certainly more like 350HP... By the looks of the curve, I'd say the car was detonating around 3800 RPM (meaning the ECU was retarding the ignition)...

Running the paper head gasket is suicidal on the 3B engines with anything more than a stock turbo, they can blow in a matter of minutes and they can potentially cause hydrolock and rods to go through the block...

HTH,

Mihnea

[sla_s2]

Mihnea, what woul you say about this curve?
sla s2

[Mihnea]

@sla: by judging the torque curve, I'd say it's the MTM racing chipset, with no knock sensors active in it. There's no way an S2 can do 303 HP and 480Nm of torque without bypassing knock control, unless you're running 107 RON fuel, which I suspect you aren't.

The driveline losses are also different between both runs, so I'd take those graphs with a grain of salt.

Most important is: never run RON 95 fuel in your car, it's gonna go bang!!!


Mihnea

[AnLe]

i have to disagree of the pinging thing, the dynorun was made by professional, using pipe from block to ear. You are right about the backpressure, #8 hot side would have helped a lot, but are very rare. This is why I cant understand people using 54/55 turbos when I can easily make more backpressure than boost mear 48mm wheel.

And before somebody proves me wrong I say the 3b/aan/aby/adu 9.3 cr ratio is bull****.
around 8.8 is more accurate.

[Mihnea]

Antti: I didn't say the engine DID ping, I said the ECU was probably retarding close to 12 degrees on all cylinders so you couldn't hear any pinging.

I don't need to have a pipe on the block to know if an engine pings or not (even is so-called professionals do it), I have direct entries into the ECU to monitor knock sensor activity and to ensure that when I tune a car, the ECU never retards the timing a single degree, not even on 1 cylinder out of 5.

Regarding the CR, a friend of mine has put 2 3B engine into bits and measured CR and he got 8.0:1. So my answer is I don't know. IMHO it's close to 9:1, but how close can you get with the 15 years' ago manufacturing tolerances?????


Mihnea

[sla_s2]

well, this is not an mtm chip. different map sensors draw different curves. i never run 95 and knock sensors are ok. i will write here when my cars engine will explode, but i know it will not happen

sla s2

[Mihnea]

Sla, ask the one who has installed your chips to email me the files and I'll analyze them and post the results here on the forum. IMHO you can't have 470/480Nm of torque on a 3B without doing what that chip had done. Installing a 250kPa MAP sensor on a set of chips that was meant for a 200kPa one (or maybe not??? no one knows so far) is already a bad thing. The MAP sensor has to go together with the boost chip.

Your chips can be anything DigiTec, SKN, Skiba Tuning, Seidl tuning or whatsoever, if you have that much torque and power (303HP at 4800 RPM??? Jesus, why did Audi install the K24-7200 turbo on the RS2 then?????), there IS something wrong with your chips.

I didn't say there was something wrong with your knock sensors, and you couldn't even know if they have been disabled in the software or not, because AFAIK, you are not a chip tuner.


Just a few more thoughts,

Mihnea

[sla_s2]

i am sending you chip files and i honestly want to hear your opinion about it. i am sorry i can not afford clever chiptuning

sla s2

[Lee]

Your losses are different on both runs. There are differents coast downs for both graphs so that looks a little suspicious to me. Was the car running in different gears for both runs, did you have vastly different tyres or was there anything else that could explain the different driveline losses? Have these results been post-processed by the tuner is some way before the graphs were superimposed as power graphs are never that smooth unless they have been through some kind of data filtering or smoothing during dyno data processing (this may be totally invisible to you even if you were watching). This would not explain the high figures but just an observation on the graphs presented.

Peak power at 4800 rpm???? Hmmmmm

[sla_s2]

mihnea, could i ask for your email?

sla@centras.lt


sla s2

[Mihnea]

sure, mihnea.cotet@easynet.be

[sla_s2]

first rum was with the same chip and 200 kpa map sensor and summer r17 tires. the other run was this winter, with 250 kpa map sensor and r15 winter tires (good that nervas was near by with his audi tdi, cause they never let me on the rollers with studded tires they would never cheat on dyno results, cause guys at groundzero are my friends and this dyno test was more experiment to see how different map sensors result the power os s2 3b. and they surely do i was happy about the result, but i am not so stupid to like the curves so much i though that peak power is so low because of too small turbo?


sla s2

Your losses are different on both runs. There are differents coast downs for both graphs so that looks a little suspicious to me. Was the car running in different gears for both runs, did you have vastly different tyres or was there anything else that could explain the different driveline losses? Have these results been post-processed by the tuner is some way before the graphs were superimposed as power graphs are never that smooth unless they have been through some kind of data filtering or smoothing during dyno data processing (this may be totally invisible to you even if you were watching). This would not explain the high figures but just an observation on the graphs presented.

Peak power at 4800 rpm???? Hmmmmm