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cressida AFM on an NA car


Niku-Sama

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i havent been arround for a bit but i still have my z but any way...

 

i managed a decent cressida AFM a while back out of a PaP in washington for cheap and i was wondering if any one had tried one on a NA car at all.

 

i figure open up the intake a bit and swap the AFM over, and by open up i mean the manifold it self and the throttle body.

 

if not i guess i am gonna guenna pig it, and see if i can get it to work.

 

while i am at it i was wondering if any one has the pinouts for the plug on the cressida AFM, i might as well see if i can get away with out having to swap guts seeing how mines NA and all i figure i might have to adjust the spring and mabe lower some values with resistance.

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oh i thought that was for a turbo.

 

see the thing is the resistance values are minor between the 2 and i think most of it may be due to an age thing, 10 ohms difference on the air temp, i could see 10 ohms difference easy between similar year AFMs from 280s depending on milage and how crusty (basicly)

 

i mean its a 77 280z but theres no word on the year of the cressida AFM, the one i got is from an 86.

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any way so the feasability of this with out swapping guts, how feasable?

 

going over it several times i cant imagine its impossible, mabe some adjustments. i mean its going to act as if the air temp is 10 ohms warmer over the Z AFM but thats at room temp as well and it'll also throw some readings requireing slightly more fuel but not much more than normal either. and thered be more air to burn up aswell

 

when i do it i guess i'll have to do some narrow and wideband air fuel guage readings or just wing it and see....probally just wing it. been thinkin about rebuliding any way if in the unlikely chance that something major happens it'll just give me the excuse to.

 

i've already replaced the coil with one of those blaster MSD coils, little bit of improvment there, and i have a set of good non leaking injectors that i'll stick on with some new seals before i do this. i have some on there that are seeping, pretty minor but any fuel out of the side is fuel thats probally meant in the engine and a loss of cc's

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i really dont see much point in swapping an engine harness and everything, not to mension i would have to weld a O2 sensor bung into the exhaust manifold and i really do not want to do that, all in all thats too much work than swapping the afms and adjusting if it works.

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If you're doing this for "more air", why not do the "turbo AFM guts into n/a AFM" swap?

 

http://atlanticz.ca/zclub/techtips/afm/sizeupgrade/index.html

 

If you're dying to be original... tear them both apart and compare. I can't imagine any real gains over adjusting the stock one, or converting to the turbo AFM body. And if you're still running everything else stock (especially after the AFM), it's not going to make much difference anyway.

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I did this just as they say in the article, and it worked just fine ;)

 

I used the Cressida AFM that has a square access door, just for reference (the car was the earlier, boxier model)

 

I didn't really feel any difference, I mean, there MIGHT have been a bit of a pickup, but with my stock TB, I didn't expect to gain much if any at all ;)

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I also did this, but with a Bosch BMW AFM. Tried modifying a Cressida circuit board, and the BMW, both with bad results. Figured I'd give it a try. Put the N/A Z circuit in and it worked fine.

 

I've always had good luck finding big BMW AFM's that, besides the circuit board, are exactly like a turbo 280zx AFM. Same size, same bolt pattern. I've only found one Cressida AFM at a pick-n-pull, and it was tiny like an N/A Z.

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  • 2 weeks later...
i really dont see much point in swapping an engine harness and everything, not to mension i would have to weld a O2 sensor bung into the exhaust manifold and i really do not want to do that, all in all thats too much work than swapping the afms and adjusting if it works.

 

You make the Z31 swap sound much more complicated than it actually is. Also, you get far better gains than the AFM tuning. That AFM is still garbage technology and the only bennefit would be seen at high rpm and wide open throttle. The Z31 MAS gives you better mixture at all rpm and throttle ranges.

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  • Administrators
You make the Z31 swap sound much more complicated than it actually is. Also, you get far better gains than the AFM tuning. That AFM is still garbage technology and the only bennefit would be seen at high rpm and wide open throttle. The Z31 MAS gives you better mixture at all rpm and throttle ranges.

 

:2thumbs:

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  • 2 weeks later...

what the heck, i have to agree to the rules every time i log in now? something is messed up i think.

 

any way, nah on the z31 still.

i've got a new set of injectors going in soon when i get off my ass and order the end o-rings for them and then i am going to give it a shot.

 

if it doesent work, meh no big, i paid like $8 for it

 

if it does then after i get my next car in order to drive arround i'll go to work on punching out the intake and cleaning up a few things.

might be time for a rebulid, only 88k miles but smokes on deceleration with the clutch out and in gear (engine braking). blueish smoke too even but the pressure rises when i am not stepping on the gas and i am engine braking so it could be something PCV related.

 

of course i dont do it all the time and its not currently insured so i am not driving it.

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