VEMS Community Forum
Technical => Ignition => Topic started by: MadsF on October 13, 2016, 11:28:43 pm
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Hello. I just finished rebuilding my new engine, as the old one went to pieces after running VE analyzer. Pretty much the first time i hit the gas, it gave a little sputter, and soon after it died on me. Proved later that the pistons 1# and 2# split into pieces between the ring grooves as well as one of them melted a bit. A lot of guys told me my map looks safe for driving (not that it is perfect). So i was wondering what your opinion might be?
Ruined engine specs : Volvo B230 8v. New piston rings, new gaskets and so on. Happened on 1.4 bar boost (20 psi) on 95RON fuel.
Pistons : https://s10.postimg.org/utb1a9f7d/20161007_182307.jpg
3D map : https://postimg.org/image/wcx7rdcb9
Map/ign table : https://postimg.org/image/bhaxg4g45
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what compression ratio? :D and your map is totaly unsafe ;D
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Compression ratio is 8,7:1.
Oh is it? People are too smart then i guess. I still dont know shit about making maps, and seemingly no one near me has the knowledge to teach me about it.
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Cant possibly be true no one here can help me? I want to learn this, not pay some one who knows something to do it for me.
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Hi Mads
I'm sure Per boddum Andersen can help you, he's running a VEMS on his 8v 740 turbo
Send your private email add to me and I'll ask him to contact you my mail is mads at vejnoe dot com
He is also in this forum from time to time.
Br Mads
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Sent you a message Mads! Thanks ;D
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I have an 940 B230FT and runs 1 bar without problems for 3 years.
Rather conservative, but it works.
(http://www.vems.hu/files/PerVolvo/volvo%20ign%20map.jpg)
Per
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Thank you Per.
I'll start a new map based on yours, i think i will make it even more conservative untill i have proper knock detection and untill i can run high octane fuel.
I've heard that cyl 3 tends to run leaner somewhere else too, but also cyl 4 run warmer than the others? - on which cylinder would you place EGT?
What other specs is on your engine?
What turbo?
530 head?
VX cam?
Aluminium intercooler?
Deka 630 injectors?
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Hi
I only think that fuel difference would be a problem during higher boost than I use.
I have no experience with fuel difference between cylinders during boost.
However in Vems you can balance the fuel injectors, so they give equal or unequal amount of fuel.
My AFR is set for 12.5 at 0.8bar boost
Per
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I will be aiming for 12-12.3 at max throttle and max boost, hard to say whether or not my cylinders are running the same fuel ratio without 4x EGT or 4x AFR. But i do not think it is enough to be a problem anyways.
I think ill start with the map you posted, and work with that, advancing the timing a bit as boost increases, to avoid knock. Do not want that to happen again..
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I will be aiming for 12-12.3 at max throttle and max boost, hard to say whether or not my cylinders are running the same fuel ratio without 4x EGT or 4x AFR. But i do not think it is enough to be a problem anyways.
I think ill start with the map you posted, and work with that, advancing the timing a bit as boost increases, to avoid knock. Do not want that to happen again..
you should retard not advance timing with bigger boost
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Well firing the spark close to top is the same as advancing in my head, isnt that what i want to do? Otherwise i am completely wrong about what i understand about this. I though that a spark fired closer to top equals less pressure on the upward motion of the piston which should reduce the stress on rods and knock aswell. :o
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Hi
Curious...How much ignition advance, boost, AFR did you run when our piston gave up ?
Was it piston no. 3 that blew up ?
A friend of mine (Volvo B200) runs 11.5-12.0 AFR at 1.6bar boost. Don't know the ignition advance as it is mechanical injection/ignition. He has burnt piston no. 3 a couple of times. The piston starts melting on the edge, down to the piston ring and then the show is done :). He is running racing fuel in his engine.
Per
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Hi
Curious...How much ignition advance, boost, AFR did you run when our piston gave up ?
Was it piston no. 3 that blew up ?
A friend of mine (Volvo B200) runs 11.5-12.0 AFR at 1.6bar boost. Don't know the ignition advance as it is mechanical injection/ignition. He has burnt piston no. 3 a couple of times. The piston starts melting on the edge, down to the piston ring and then the show is done :). He is running racing fuel in his engine.
Per
No sir, it was 1 and 2 that died. 1.4 bar 12AFR and timing as written earlier
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Well firing the spark close to top is the same as advancing in my head, isnt that what i want to do? Otherwise i am completely wrong about what i understand about this. I though that a spark fired closer to top equals less pressure on the upward motion of the piston which should reduce the stress on rods and knock aswell. :o
More ignition advance makes the firing farther from the top.. The closer from the top the hotter the EGT. So there is compromise for the ignition advance to reach between the risk of detonation and a too high EGT temperature, I think.
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Well firing the spark close to top is the same as advancing in my head, isnt that what i want to do? Otherwise i am completely wrong about what i understand about this. I though that a spark fired closer to top equals less pressure on the upward motion of the piston which should reduce the stress on rods and knock aswell. :o
More ignition advance makes the firing farther from the top.. The closer from the top the hotter the EGT. So there is compromise for the ignition advance to reach between the risk of detonation and a too high EGT temperature, I think.
Oh okay, i just understood it as the exact opposite ???
Anyhow, i still get the basics, just got retard and advanced wrong, not that i was actually going to put the table in the wrong direction.
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(http://i68.tinypic.com/23kst8z.jpg)
Comments? Map is pure guesswork and estimates with inspiration from other maps for similar engine setups.
1,5 bar of boost
8,7:1 compression
4 cyl
Shell V-power fuel
Stock 530 cylinder 8v head (VX cam)
Stock intake with 875 injectors
T3 TS manifold with Borg Warner S200 turbo (rated 500+ hp)
4" exhaust all the way out
Power goal is 350 hp as safely as possible. Will be used for 201 and 402 m drag (for fun only)
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It's save, if your EGT isnt too high. I would add a little advance. I noticed VAG engines with 8.7comp (drilled Audi S2 Pistons) start to knock hard 300kpa,17°Ign, lambda 0,80 @4500rpm and pumpfuel (98 Oktan in Germany). Stay far away from this and it will be fine.
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I will keep an eye on my EGT, if it gets too high, i'll advance a bit.
Thanks for the warning, how did you avoid knock? A bit less timing?
- I can't seem to get my knock setup to work properly, not enough to save the previous engine at least.
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It's save, if your EGT isnt too high. I would add a little advance. I noticed VAG engines with 8.7comp (drilled Audi S2 Pistons) start to knock hard 300kpa,17°Ign, lambda 0,80 @4500rpm and pumpfuel (98 Oktan in Germany). Stay far away from this and it will be fine.
Why so much advance? Is that tunned to knock limit or MBT on dyno?
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It's save, if your EGT isnt too high. I would add a little advance. I noticed VAG engines with 8.7comp (drilled Audi S2 Pistons) start to knock hard 300kpa,17°Ign, lambda 0,80 @4500rpm and pumpfuel (98 Oktan in Germany). Stay far away from this and it will be fine.
Why so much advance? Is that tunned to knock limit or MBT on dyno?
In this case it was knock test.
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It's save, if your EGT isnt too high. I would add a little advance. I noticed VAG engines with 8.7comp (drilled Audi S2 Pistons) start to knock hard 300kpa,17°Ign, lambda 0,80 @4500rpm and pumpfuel (98 Oktan in Germany). Stay far away from this and it will be fine.
Why so much advance? Is that tunned to knock limit or MBT on dyno?
In this case it was knock test.
I did few engines like that on dyno, and no need for that many advance.
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To future readers .... This ignitions map works fine on a Volvo B230FT engine with a S200 turbo and 1,5 bar running Shell V-Power, IAT arround 30 degree c above ambient, AFR is arround 11,3.
I've burned 300 liters of V-power on these settings, no issues. Max EGT was 820 degree c (full chat on the motorway, usually only high 700)