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I was reading over an old HPI mag and noticed an article on fitting a pair of Z32 AFM's to a GTR32. Previously the car had 200rwkw@14psi and after the AFM swap they were able to get 260 mainly because of the greater range of resolution and tuning the Z32 offered.

My question is whether any gain could be had on a GTS25t with this AFM, the article said that the ignition maps had to be changed even at idle, all I have at present is an SAFC so would this AFM swap be only for PowerFC equiped cars?

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I remember that HPI article, I think they said most of the power gains came from the ecu remap and they weren't really sure how much the afm's by themselves would do.

No real need to use it on a 25t unless you're running out of tuning resolution on the current afm. Both are 80mm. S-AFC wouldn't be able to modify the afm signal anyhow, you'd need a rom daughterboard or powerfc.

What mods have you done and what kind of power are you chasing?

When I put the Z32 afm on my car, it ran bulk rich... All the way from idle to redline... This is not just full throttle, but part throttle too, so unless you've got a full ecu to take advantage of that, you'll probably find that your economy will go to *****. Obviously you'll be able to tune your full throttle with teh afc, but part throttle won't work.

The actual diameter of the AFM between the RB25 and the Z32 afm's are both 80mm, so you're not going to have any less restriction by moving up to the z32.

matt

Originally posted by turbomad

I was reading over an old HPI mag and noticed an article on fitting a pair of Z32 AFM's to a GTR32. Previously the car had 200rwkw@14psi and after the AFM swap they were able to get 260 mainly because of the greater range of resolution and tuning the Z32 offered.

My question is whether any gain could be had on a GTS25t with this AFM, the article said that the ignition maps had to be changed even at idle, all I have at present is an SAFC so would this AFM swap be only for PowerFC equiped cars?

i was running a standard rb25 afm on my car. the decision to change came because the stock one was hitting 5.1volt in the midrange. fortunalely i had a powerfc so i could do the change quite easily.

i swopped the afm and altered the setting inthe powerfc. after which it ran perfectly. no problems. obviously it exposed more of the powerfc map and those sections needed some work. wasnt really rocket science to add in the next 2 rows though. now im able to tune the topend with the z32 showing about 4.5 volt by 5500rpm.

powerfc owners may have noticed that the stock afm will only expose up o L16 on the map. the Z32 will show upto L18 and the VH41 will expose the whole map.

i really dont know about the full remap scenario. i flicked the switch and it worked first time.

basicly there is not benefit unless you have maxed out the old one. i didnt get an exact number but its near the 200kw mark that the old one runs out. seems to me to be more that the stock turbo can push so dont worry unless you upgrade.

anonymous.

I'm getting 188rwkw now with the AFM voltage around 5.06 mark.

I'd like to achieve the max amount I can on the standard injectors and ECU, which is 210rwkw so I was told. I'm only running 12psi through the stock turbo now, so maybe I could try 14psi but I fear the AFM would top 5.1v, alternatively I was thinking a different turbo might be the go as I would like to have more rwkw around the 4000-5500 rpm range, rather than only at peak rpm, what turbo can anyone recommend, VG30, HKS2540, GT30 etc....

Also can the SAFC still tune the A/F ratio if the AFM is at 5.1v?

once you hit 5.1v i wouldnt recomend trying to tune further. basicly the ecu has no idea where it is. could be 13psi or maybe it could be 28psi. bad idea. as you go over 5.1 volt you get the lean out / over advance condition which makes engines go bang.

a safc can convert to z32 afm. never done it myself but the manual says its possible. also seems like a bad idea as the stock maps have no good points to be intercepted to.

hks 2530/35/40 are very nice. call around and see if any wreckers have any? for the cost of mangling a vg30 or hi-flowing you may as well spend the extra few hundred and get an hks. going rate is about $2000 i think.

at 215rwkw at 6000rpm i had a duty cycle of 90% on the stock injectors and an afr of 11.5 ignition timing was about 16 degrees - other cars may differ though. if i remember right the afm was maxed out for a while. these numbers were achieved at hybrid and thier dyno seems reasoably accurate. i like thier dyno for tuning cause there is no wheelspin clouding the readings.

I recently fitted a Z32 AFM to my R32 GTSt with great results.... I wasn't maxxing old the old one but it broke so I thought why put another RB20 one in.

I have made my own custom ECU and chip for it.

Results: 170 RWKW before my stock injectors ran out at 1.1 bar.... Custom T3/4 should be good for 1.7 bar....

E-Mail me for more info

Ditto on the 5.1 volts... You can still tune however, it's just difficult because once it hits 5.1v it's pretty much just a guessing game as far as tuning goes... With the powerfc's the stock afm isn't much good because you can't retard any more ignition off because there's no points available. So basically you just have to pick a conservative value for your ignition on load point 20 across the rev range so if the boost does spike, you won't melt a piston.

As mentioned above... Full throttle can, but part throttle would be very rich.

2535 is probably the biggest you'd want to go without getting a compressor/exhaust wheel mismatch... The 2540 is too small on the exhaust side, and take longer to come on boost than they should... They also seem to require a lot more boost to make decent power than the 2535 does. If you can find one, you'd be better off with a 2835R or a 3037... They're both really well matched turbo's, and should make power fairly easily.

When you say that the AFM maxed out, were yuo referring to the RB25 or Z32 item? I've got about 310 rwkw in mine (as seen by a number of forum members), and I think my max AFM voltage was 4.9v...

What sort of turbo setup do you have, and where aboust are you based?

Cheers,

matt

Originally posted by no_name

once you hit 5.1v i wouldnt recomend trying to tune further. basicly the ecu has no idea where it is. could be 13psi or maybe it could be 28psi. bad idea. as you go over 5.1 volt you get the lean out / over advance condition which makes engines go bang.  

a safc can convert to z32 afm. never done it myself but the manual says its possible. also seems like a bad idea as the stock maps have no good points to be intercepted to.  

hks 2530/35/40 are very nice. call around and see if any wreckers have any? for the cost of mangling a vg30 or hi-flowing you may as well spend the extra few hundred and get an hks. going rate is about $2000 i think.  

at 215rwkw at 6000rpm i had a duty cycle of 90% on the stock injectors and an afr of 11.5 ignition timing was about 16 degrees - other cars may differ though. if i remember right the afm was maxed out for a while. these numbers were achieved at hybrid and thier dyno seems reasoably accurate. i like thier dyno for tuning cause there is no wheelspin clouding the readings.

matt, i maxed out the stock rb25 afm and didnt persue the tuning any further as i didnt want to compromise on the part throttle tuning. i havent run the z32 hard yet cause ive had a whole bunch of small propbelms with the car. ive also recently started popping hoses off as ive raised the boost. hopfully next week il try it again with decent boost. ive seen 4.5 though with the z32 meter.

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