Dual Afm On Singelturbo Rb25det

[Finny]

This is soo easy to fix...

Do an AFM bypass then get your PFC tuned to suit.

You will get double the range out of your AFM for free exept for the cost of a quick retune.

Basicly get a Y connector like you said but just dont have an AFM on one of them... so only 50% of air or so is messured and dyno will fix up the timing and Air Fuel mixtures to handle it.

[Mr Jollwah]

I made an error before you would double the k value if AFM was only measuring Half the air.

Just thought I'd fix that up...

[maka]

I had recently borrowed my mates power fc kit.. for an rb25..

Power FC and a few other bits and pieces including a very large AFM.

I beleive it was off a subaru of some description..

The only difference was the wires.. so after measuring the wires around, I found that I had to change signal and common wires around... worked a charm, but was only running stock boost, and was tuned for 550cc injectors.. so naturally my car was slower than with the stock afm..

I'd say try and find a larger afm with 3 wires.. Its not that difficult to change the wires around, and you should be able to get higher values.. so therefore the result that you want.

Or otherwise change the thermistor inside your Z32 AFM to a different temerature co-efficient.. that might also get you higher vlaues with more boost pressure.. But yeah might have trouble with the amount of air you are able to pass through the Z32 area..

just my 20cents worth

[jeffworld2]

what if you had a twin setup? i am very interested as i have bought a working rb25dett setup, but have an rb25 power fc. i also have an safc so was going to use that, but this looks much better?

if i use a dead afm on one turbos intake, and a "live" one on the other, than they should have the same inlet restriction right... i need guidance for the cheapest/easiest way out lol.

turbos are from r33 gtr

[h2k]

I'm still doing a bit of research on this area because I DO want to go for a dual afm setup if only because nobody else has done it yet

Anybody know where I can buy a prefabricated Y-pipe like this one on the picture? it's from a singelturbo rb26dett conversion:

[Blue_GTR]

Hmmm possibly Trust or HKS would have something to suit from one of their T51R or T88 type single turbo kits using dual AFM. Most likely Trust/Greddy would be your best bet.

[Adriano]

Blitz had one for sale, ask him he would know(I think it was greddy)

[joeyjoejoejuniorshabadoo]

Makes sense to use a dummy afm as long as you have the same pod and pipe dimentions, and the filters in a spot where they can suck the exact same amount of air...

[GeeTR]

I'm still doing a bit of research on this area because I DO want to go for a dual afm setup if only because nobody else has done it yet

Anybody know where I can buy a prefabricated Y-pipe like this one on the picture? it's from a singelturbo rb26dett conversion:

http://www.nengun.com/trust-greddy/suction-pipe

[W0rp3D]

Was thinking of another application as well, since one of the problems with airbox's is how restrictive they are once you start getting high up in the horsepower range, could you possibly run another pipe underneath the intake (assuming its a low mount and the pipe would be heading towards the ground) pipe, this would give extra flow and be hidden from unwanted eyes.

Also if this is done on the first batch of upgrades of turbo and injectors would it allow you to keep the factory afm or would you still need to use a z32?

[Adriano]

If the bypass pipe was an appropriate diameter, there is no reason you couldnt use the standard AFM. One thing to bear in mind, is that you would want the bypass to flow roughly the same amount of air as the AFM, and make sure you clean the airfilters at the same time, as any differential from when the car is tuned could cause a drastic change in the A/F ratio

[jeffworld2]

just an update.. on my twins i have them both being fed through a single afm. this was the only way we could accurately meter the air going in, and you have to know how much is in each turbo.

so im running a big afm and rb25 power fc

[nicksamaniac]

Ive been researching this topic in regards to my afm "hitting the ceiling" so to speak, if 2 afm's wired in parallel gave the same/equal voltage output but at half the value of the single afm, could i just double the percentage the power fc see's? Or tune to suit?

I believe this would be a more accurate way to measure load as aposed to the bypass inlet idea?

Ideas?

[Ben C34]

Nick, why not just get one larger afm?

[nicksamaniac]

I was running a z32, but was having issues with it, it was giving and/or the power fc was reading it as a noisy signal, like it was ever so slightly out of tune?

Hard to explain, it was always 1 cell off where it should be, or the load ramp table needed modifying. I put the stock afm back in and went back to the power intake setting and was sweet. But it hits 5v at 3/4 power.

[Ben C34]

Rather than run 2, here's another budget idea. Chop up a stock afm and put it into a larger pipe, maybe 3.5 or 4 inch.

I saw a pic of a z32 cut up and put into a pipe, will try to find it again.

[Ben C34]

Actually I think it was in the same diameter tube for a both through setup.

Might be a key to chop it up and get it into a bigger tube.

[nicksamaniac]

Sweet idea, might give that ago.

Ive seen the r35 afm design, i thought about that too but I'd need the load ramp table to start off with.

Also, Can the standard table be stretched out with datalogit?

To cover a broader airflow.

[1kr33steven]

Not sure why it hasn't been suggested but I just went blow thru with a stock afm as long as you can tune/calibrate and it references the right air flow for the fuel required its all good,

[nicksamaniac]

Sounds good in theory, but how well will it handle 20+ psi of boost?

And how well can it correctly read air temp?

Seeing it will either be mounted on the hot side of the charge or the cold side of the charge?

Im not entirely convinced it would work 100% correct all the time?