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Power Fc + Pinging

croat

By croat,
in Engines & Forced Induction

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croat Mentor

croat

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just had my car tuned made 265rwkw on 17psi. On the dyno using the lap top software the car registered no pinging (30-40 on full load). Now we took it for a drive on the road and its making 140 knock on the hand controller.. im puzzled!

The tuner and my mechanic listened carefully but heard no pinging. but at 140 knock on the hand controller would definately be heard when driving or near the motor. So my question is is my knock senser dodgy? or is it too sensitive and just picking up engine noise etc?

Has this happened to anyone before?

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paulr33 Grand Master

paulr33

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the first step would be to isolate what load point its coming from, clear the max knock value, plod arond and see if it spikes up again. if it does then its in the low load area (unlikely). clear the max again and do some medium cruising and check the max knock (likely to be the cause). then try some heavy driving and see if knocks consistently. if you are able to reproduce it try IGN/INJ retard a few degrees of timing and see if that helps it, if so its just a few load points where the timing is too high. if you can make the knock go away by taking out a few deg then get a friend to drive and punch it, watch map tracer and wait for engine flash to come on and pick what cell is doing it, then goto IGN and back out a few degree's for that cell. you should narrow it down within about 5 minutes of doing this.

dyno tuning is fine but road driving does change the load a little, for example going up a slight hill in 3rd will have different load variances to a fixed dyno if that makes sense. nothing to be worried about just a few points need to be smoothened out on the road.

nice power you made, thats on the gt-rs yeah ? good stuff :)

croat Mentor

croat

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Paul/R31 it does not knock all the time. most of the time i boot it and its fine but sometimes the light comes on. The laptop read very low knock levels so im not surew which to believe. The mechanic and tuner said there was definately no knock but the sensor says otherwise.

Yeah making 260rwkw on GTRS on 17psi with more in it. They still have not played with the exhaust cam as my exhaust manifold (one of those stainless ones) cannot flow enough and boost begins to spike. Next step is to get a custom manifold and go for 20psi :P

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

you generally dont hear the ping @ an audible level while driving.

I reckon it'll be just one cell or two thats causing the problem.

Its very easy and common to happen as dyno/street are different.

You arent say... riding @ 4000rpm then planting it on a dyno etc.

Just different conditions which... probably a cell or two :P

cameron Mentor

cameron

Posted
Posted
im tending to think my sensor is just picking up engine noise and is too sensitive. I cant hear any pinging so it should be ok?

What R31Nismoid just said, you can't hear audible detonation and thats what kill's engines.

Do what paul said try taking a few deg out on the overall correction to see if it makes a difference.

Also the load on a dyno can be a little differnt on the street, i've seen up to 3 load point change from what was being read on the dyno.

bmxwrx Enthusiast

bmxwrx

Posted
Posted
just had my car tuned made 265rwkw on 17psi. On the dyno using the lap top software the car registered no pinging (30-40 on full load). Now we took it for a drive on the road and its making 140 knock on the hand controller.. im puzzled!

I'm surprized they tuned it with knock that high on purpose :P

After my tune I too had a little knock when jumping hard on the throttle at around 4000rpm.

I think you'll find that it is most likely slightly overboosting into a cell that would'nt have had an overboost situation on the dyno run.

markr34gtr Experienced

markr34gtr

Posted
Posted

how much timing in the tune...

usually knock levels around 20 at full boost and high in the rpms is your goal on the dyno. as when you drive it on the street knock levels increase as street driving has different load....

i would say the tune is to agressive....timing is not the only thing that makes power.....

hope this helps.

The Mafia Grand Master

The Mafia

Posted
Posted

same here, tuned my car on the dyno, 20 knock, and then took it to the street and pinged up to 80 - 100.

Dyno's don't load the car as much as the road.

Get it re-tuned. Or DIY the ign retard on the street if you have a datalogit.

nF Collaborator

nF

Posted
Posted
i have the same problem, genrally in 3rd 4th boosting up a hill...

i think my car is going slower and the engine is making a groaning noise.

i wouldn't do this too much, if you can hear the engine straining downshift or something

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
I think you'll find that it is most likely slightly overboosting into a cell that would'nt have had an overboost situation on the dyno run.

I had the knock on the street when mashing it around 5000rpm in 3rd.

It certainly wasnt over boosting... just one cell had a slightly off value.

Its really a 5 mins (at the worst) fix if you can remember approximates of what RPM/Speed/gear and throttle position (usually WOT) then the tuner can work that out no worries

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
Just had it out last night. No problems at all. reving it hrd as and knock didnt go over 11. seems ok. no idea maybe cause of the heat?

pretty much.

As i said (a few times) it'll be one or two cells that have a slightly higher ignition value.

Next time it happens, note down roughly what speed/rpm/gear etc and tell your tuner. Should be able to fix it and it'll never happen again, heat or otherwise

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