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R33 Gts-t Boost Cutting

syfon

By syfon,
in Western Australia

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GTS-t VSPEC Grand Master

GTS-t VSPEC

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My brother recommended to take it out to improve fuel economy as modifications to the vehicle are currently limited to an FMIC, air pod and turbo-back exh.

After i took out the SAFC2 the car was running perfectly normal, no boost cuts, smooth as silk; it was only once i had changed the plugs that i got the boost-cuts.....

Dude, will all due respect, your brother doesn't know what he's talking about.

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Munkyb0y Grand Master

Munkyb0y

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lol ^

he's right. u need some kind of piggy back to bend the signal, so that you can run more boost without reaching the stock boost cut limits.

also, you said the problem started after you changed your plugs. what gap are the new ones? if they are standard nissan, they will be 1.1mm. you need to use closer to 0.8mm. coz it might well be a spark issue. all power disappears for a second at around 4000 - 5000 rpm when the vct timing changes. thats a standard occurance on skylines with spark issues.

syfon Veteran

syfon

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Dude, will all due respect, your brother doesn't know what he's talking about.

He owned a 450hp R33 gts-t, but I'm not going to argue or say anything more....

Anyway, the SAFC2 can't have anything to do with this as after i removed it the car was still running perfectly fine....

syfon Veteran

syfon

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lol ^

he's right. u need some kind of piggy back to bend the signal, so that you can run more boost without reaching the stock boost cut limits.

also, you said the problem started after you changed your plugs. what gap are the new ones? if they are standard nissan, they will be 1.1mm. you need to use closer to 0.8mm. coz it might well be a spark issue. all power disappears for a second at around 4000 - 5000 rpm when the vct timing changes. thats a standard occurance on skylines with spark issues.

sigh :)

The new plugs are the NGK (i think) replacement plugs called platinum laser, and they are gapped at 1.1mm. To change the gap from 1.1mm to 0.8mm can i simply remove the plugs re-gap them and put them back in? Or do i have the buy new plugs?

GTS-t VSPEC Grand Master

GTS-t VSPEC

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Dude, I'm not going to slag your brother off, just saying he was wrong. If you don't get somethign for them to tune, then you may well be wasting your money on the dyno tune, as all they'll be able to do is wind back the boost controller till it stops hitting boost cut.

Munkyb0y Grand Master

Munkyb0y

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sigh :)

The new plugs are the NGK (i think) replacement plugs called platinum laser, and they are gapped at 1.1mm. To change the gap from 1.1mm to 0.8mm can i simply remove the plugs re-gap them and put them back in? Or do i have the buy new plugs?

you could do that. but you'll have to be careful because the platinum tips can crack. so use a softish piece of wood to tap the tip against, gradually, till you get it there.

or you could go buy some NGK copper plugs, already gapped to 0.8mm for under $20 for 6. they oftenwork beter anyway, but need to be changed around 10,000kms.

syfon Veteran

syfon

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Dude, I'm not going to slag your brother off, just saying he was wrong. If you don't get somethign for them to tune, then you may well be wasting your money on the dyno tune, as all they'll be able to do is wind back the boost controller till it stops hitting boost cut.

It's fine man, i relaise you're not doing that. It was just that he told me to get the boost controller tuned for a Lo and Hi setting....

syfon Veteran

syfon

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you could do that. but you'll have to be careful because the platinum tips can crack. so use a softish piece of wood to tap the tip against, gradually, till you get it there.

or you could go buy some NGK copper plugs, already gapped to 0.8mm for under $20 for 6. they oftenwork beter anyway, but need to be changed around 10,000kms.

Ok i'll give the first option a try and if it becomes too difficult i'll go buy some copper plugs already gapped at 0.8mm.

One other thing, won't the platinum plugs foul quite easily once you start turning the boost up/etc?

syfon Veteran

syfon

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Whats boost going up to on your gauge ??

My boost gauge is my boost controller :)

It goes to 0.7 bar on Hi setting, 0.5 bar on Lo setting. So thats 9.8psi on Hi and 7psi on Lo. Boost-cuts on both settings

GTS-t VSPEC Grand Master

GTS-t VSPEC

Posted
Posted
One other thing, won't the platinum plugs foul quite easily once you start turning the boost up/etc?

Fouling is caused by overfueling, which is what will happen now that you have the SAFC removed. If you had the SAFC you could have increased the boost, and then got the SAFC retuned to keep the AFR's all good.

I agree with MonkeyBoy, get the NGK BCP6ES copper plugs, there cheap, come gapped at 0.8mm and means you won't wreck the platinums if that isnt the real problem.

syfon Veteran

syfon

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was your bov leaking?

by blocking off a leaky bov you could have increased the boost pressure the engine sees and thus hit boost cut.

We put in the solid BoV gasket the day before i changed the plugs and it was running absolutely normal, just gave the turbo flutter sound....no boost-cuts then....

clip14 Rising Star

clip14

Posted
Posted
We put in the solid BoV gasket the day before i changed the plugs and it was running absolutely normal, just gave the turbo flutter sound....no boost-cuts then....

shouldnt have listed that as one of the things you changed to cause this problem (your first post)

hard to help unless all the info is there

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