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Nateb

The rb25det sputter at 5k

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Hello all I have a 1992 rb25det swapped gtst.

So the run down. Car idles at about 1k but its consistent.

Has a power fc. Full 3inch back . Intake and that is all as far as mods go. 

Car pulls -20 in vac

And hits full 7psi boost. 

However car feels slow as dirt and at about 5k rpms to 6k it'll sputter really bad and not want to go anywhere. But if you only hold it to about 2 psi till 6k from 6 to 7.5 k it'll feel like a rocket and like its suppose to be. 

 

Things I've done.

Checked for boost leaks. I found 2 small ones and fixed those. 

Changed plugs however I haven't re gapped them from the .8 they come in. 

Changed and liquid taped coil packs. 

Car runs extremely rich like 9 when full boost. 

Afm doesn't have any sticker or anything on it for me to know which one it is. 

 

Any info as to what else I can do to get this car running good would help and thank you.

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Will be doing that within the week. Just want to make sure there was no problems before I get there. 

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9 AFR on boost is uh, plenty rich. But how do you know it's running 9:1?

If you have the means to accurately determine that... and a powerFC you should be able to lean it out to a far more reasonable AFR. That said, that will be the first thing the tuner does. I would consider having a spare set of plugs handy if the car is driving around on 98 with a 9:1 AFR because they will foul up pretty quickly and you'd hate to be caught out on the Dyno like that.

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The reason I ask is it'd be strange to have a wideband, and a modifyable ecu, and have a 9:1 AFR on full boost unless as mentioned a bit above, still running stock map.

But even then the base map wouldn't be that far out unless something is decidedly not stock anymore, like injectors, or the AFM isn't what the powerFC thinks it is.

The answer really is tune it. If not comfortable and it's getting a tune anyway, drive it to the tuner very conservatively and have the spark plugs ready to go when it's going on the dyno 😛

Any issues (if any!) will become more apparent once the AFR is under control.

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Yea I thought it was very strange as well. I had bought the car with the swap and pfc and was trying to figure out why it smelled like gas and what not so I installed a wideband to see. 

I honestly dont think that afm is the stock one which is what it believes is on there. 

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So after looking at my maf and various other ones I believe mine is the z32 maf which would make what you said @Kinkstaah correct. Will be taking it for a tune this week with an extra set of plugs lol. 

 

Side note there is no label or anything on my maf so I'm just going by looks comparison 

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