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Speed Limiter Reached Now Loss Of Power

Pattey21

By Pattey21,
in Engines & Forced Induction

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Pattey21 Proficient

Pattey21

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Posted (edited)

Hey guys just got my car tuned with a piggy back safc 2 and went to a mates property to test it out, and i reached the speed limiter, was soft i didnt notice it was speed limiting for a second.

I did check the SAFC max hold knock value and it was like 120 however i didnt hear any bad sound or noises it simply stopped accelerating.

However after that the next time i went to boost it wasnt as quick.

The car still holds boost and no bad sounds/smoke or missing. It is still as smooth as before but its like its lost 30kw throughout the rev range.

Could it be stuck in its knock map, because i cant think what else it could be?

Im going to lay off boosting it and have set a warning value for the knock to see if its recuring till ive sorted it out.

cheers

Edited by Pattey21
Pattey21 Proficient

Pattey21

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Yeah that the plan hope to get it on this week. When you hit high knock did you hear anything

When my car hit 100+ knock a week later it required a rebuild

Have it checked out on a dyno with some knock phones on just to be 100% sure

Yeah that the plan hope to get it on this week. When you hit high knock did you hear anything

levinboy Grand Master

levinboy

Posted
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Yeah that the plan hope to get it on this week. When you hit high knock did you hear anything

Yeah that the plan hope to get it on this week. When you hit high knock did you hear anything

Couldn't hear anything

But once put on the dyno with phones on you could, bearing was ready to spin so was lucky in that sense

Pattey21 Proficient

Pattey21

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1st Thread - Strange Dyno Results (SAFC)

2nd Thread - Speed Limiter Reached (SAFC)

3rd Thread (to come) - Engine Blown (SAFC)

Don't say you weren't warned :no:

Well it will be getting checked out on wednesday. Guess you will have to wait to see if this turn into a trillogy.

Pattey21 Proficient

Pattey21

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Update:

So started taking things apart, all spark plugs were a dark medium brown/tan/earthy colour not too worried as i put in a bottle of octane boost prior to tune intending to reduce possible knock, however found out after that it can actually increase it.

Also two of the spark plugs had shit on the outside however i dont think the were seated correctly/ washer wasn't flat.

Replaced the fuel fikter too and dropped oil for good measure.

Cleaned a few sensors afm/cas/throttle.

Took for a spin all the same still smooth just lacking power. I did notice however that it did pull a bit harder with say 2/3 throttle or at least it didnt pull much harder between 2/3 and WOT.

Was watching the knock sensore like a hawk and was fine.

Super Drager Mentor

Super Drager

Posted
Posted

The problem with an SAFC is that it intercepts and changes the AFM voltage/signal. As it does this it also effects ignition timing, add to the fact many tuners will not use any form of knock detection when tuning an SAFC simply because they do not know this. So while you may get that perfect fuel curve you could be pinging at one load point. In your case i'd say because you put octane booster in for the tune it could be pinging now. He might have gotten the fuel curve right but now without any octane booster its becoming troublesome.

Pattey21 Proficient

Pattey21

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The problem with an SAFC is that it intercepts and changes the AFM voltage/signal. As it does this it also effects ignition timing, add to the fact many tuners will not use any form of knock detection when tuning an SAFC simply because they do not know this. So while you may get that perfect fuel curve you could be pinging at one load point. In your case i'd say because you put octane booster in for the tune it could be pinging now. He might have gotten the fuel curve right but now without any octane booster its becoming troublesome.

Thats a good point, i did talk my tuner yesterday and he was watching the knock values. also thinking it may be the fuel pressor regulator, as it did have some dirty fuel 9 months ago, could have clogged to some degree and now with the higher boost cleaned up a bit. Would explain the lean afrs prior to tuning.

Pattey21 Proficient

Pattey21

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Reg won't respond that way.

Ah lame,

i just dont understand why my AFRs were lean prior to tuning, if the fuel pump was dieing, then would it be able to supply more fuel when being fooled by the safc.

The green run shows no correction and a rather lean AFR. the tuner had to increase the afm signal rather than trim it which is highly unusual.

I think this is connected to my current problem

post-88652-0-52162000-1366066954_thumb.jpg

Pattey21 Proficient

Pattey21

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Your AFM may be at fault too, i have a similar problem ATM with lean AFR's and a mates afm fixed it.

Okay cool well ill be making a list for my tuner of what ive have done/ what it might be ill add that too.

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