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Discussion Starter #1
hey guys, i was the one who started the thread which got carried away 2 weeks ago called: "MAF Vs. MAP - whats better?" anyways i was at a shop last few days and saw a car which really caught my attention.

k so here's the setup.. 2 low mount turbos.. fed by custom made aluminum tube with apexi filters on each end, a rather, "cold air" intake kit setup... after the turbos the air runs through the intercooler.. then back up into the engine bay.. where it meets ONE 300ZX MAF!... then it goes into the standard intake plenum.

this is all controlled by an oem ecu.. heres the kicker.. its not an RB26 ecu.. its an RB25 ecu! tuned using nistune on dyno!

as far as i can see this is ALL advantage with ZERO drawbacks!

advantages:

- ONE big maf instead of 2 small ones
- RB25 ECU is easy to find and cheap to purchase
- MAF benefits of much smoother tuning, and idle, better mapping resolution,
- no issues with Venting to Atmosphere BOV's
- 100% accurate reading of actual air mass regardless of outdoor temp.
- and due to the positioning of the setup.... no concerns about boost leaks!


i can't think of a single draw back... can [email protected]?


lemme know..

also if any of you have pics of this setup PLEASE put them up.. im dieing for more details on this.
 

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Upgrading on the RB26 using MAF usually means fitting TWO 300ZX MAF sensors ;)
Easily selectable within eg. the PowerFC.

I can't think of a single reason for using a "chipped" ECU other then for compatibilty with Consult. One 300ZX TT MAF will run out of puff before the 2 OEM RB26 units.

The 300ZX guys chip their ECU's and fit a second(!) 300ZX TT MAF when going for more power.

Marc
 

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Discussion Starter #3
maybe it was a Q45 maf? regardless it was one - big - MAF...

in canada we prefer to tune with stock ECU and nistune on a dyno because its the most cost effective way.

can you recall anyone running this setup? or any drawbacks to it?
 

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sounds a good setuo previding the MAF can flow enough air. But reading the above post, well it sounds like its a waste of time.

Out of intrest, has anyone used a MR2 maf? i was working on one the other day and it looks 3 times the size of a rb26 MAF.
 

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Check with **** about the lemon when he first bought it,if I'm not mistaken he said it featured 1 blow thru maf originally when he got it.
The rb25 ecu is is a whole other issue as there quite a few differences to the rb26, some z32 guys use the rb25 maf as they are more or less interchangeable but the rb26 ecu would require a whole bunch of changes to work.
PS.I run a power fc from a rb25 on my z32.
 

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Upgrading on the RB26 using MAF usually means fitting TWO 300ZX MAF sensors ;)
Easily selectable within eg. the PowerFC.

I can't think of a single reason for using a "chipped" ECU other then for compatibilty with Consult. One 300ZX TT MAF will run out of puff before the 2 OEM RB26 units.

The 300ZX guys chip their ECU's and fit a second(!) 300ZX TT MAF when going for more power.

Marc
It is not "chipped" ECU... Nistune reprograms the standard and the advantage is that you can use all the standard sensors (including knock sensors which pull timing if you get a batch of shit fuel etc). Plus drivability is usually better on OEM computers.

Mike

PS: smart idea mate
 

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Positive: It gets rid of a lot of shuffling symptons 9/10 times and it cleans up the engine bay.
Negative: You need to make a metal housing for the z32 sensor, or you will likely 'pop' the plastic housing(its not designed for positive pressure).

Dependant on cooler piping size, either run two afm sensors in the pipe (if pipe is equiv of z32), or one sensor if the piping is closer to the cose sectional area of 2x z32 afms.
GTR afms are mearly averaged anyway.

This is a setup ive been considering for some time.
 

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It is not "chipped" ECU...
I wasn't talking about Nistune, which is not very widely used over here. www.twinchip.com I was talking about them :)

I'm very curious about knock sensors and hardcore engines, knock sensors are microphones, trimmed to a specific sound which may or may not change with the addition/removal of components not originally on the engine. Therefore I wouldn't trust
the knock detection on a reprogrammed ECU. Engines that make big power need constant attention, specials for Specialists, if this makes sense. But this is a total other
discussion.

Marc
 

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A single Z32 isn't enough for any real power. Ford Lightning MAF's have been used with ok results. Jim Wolf here in the US has done some conversions.

The issue as someone said is the positive pressure on the housing. At big kid boost, I think it will pop.

I know that several groups have done setups like this, but by then I am normally on an ECU with a MAP sensor.
 

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Discussion Starter #10
hey,

just to clear the air a little...

the car i saw at the shop was running ONE big MAF in blow-through orientation.. AFTER the intercooler... and WAS using the RB25 ecu.

as far as destroying the maf with positive pressure... i can see that being an issue.. but this guy was runing 21 PSI!...he had 2860-5's.

so by seeing this car alone i know its possible to due.

im just wondering if theres any real drawbracks. heres what ive managed to list as drawbacks so far based on your responses:

1) positive pressure may destroy maf
2) one big maf may run out of range on voltage before 2 oem ones do.
3) rb25 ecu MAY NOT have all the sensors hooked up (ill look into this with my tuner)


anyone able to come up with any other issues? cause as it stands... this still seems the BEST way to do rb26 engines. just for shear cost and easy set up.. think about it. you buy ONE maf instead of 2. you buy a super cheap rb25 ecu. and mod some aluminum pipes after the intercooler to adapt the maf.

compare that to buying sayin a PFC at $1000, plus 2 maf's at $300 each. or map sensors and d-jetro stuff.

but u get the advantage of super smooth drivability and safety of using a MAF based system. AND no worries about VTA - BOV's or boost leaks!
 

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Nothing wrong with a well set up MAP sensor based system imho.
 

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Discussion Starter #12
map has huge drawbacks dude...

starting with the cost! first thing is you need PURCHA$E a new ecu... easily will cost over $1000 + what ever harness + map sensor you need.

second it doesnt give good driveablility for vehicles runnin low boost like 16 or 17 PSI (1.2 bar)

third its not accurate enough at all for people who live in changing climates where temperatures can range from +40 degrees C to - 40 degrees C. (most of north america, and europe)

i think that covers the cons/// lol
 

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Really? I thought the only real issue (apart from cost) happens where you need to drive at hugely varying altitudes. A decent MAP setup will include intake temperature measurement. I run VPro, and it's fine at 1.2 bar.
 

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Seen this done a few times, the thing is it works!! You can use the stock ecu and it doesn't cost much to do.

But I know of 1 that blew apart on a high boost drift, but then it was a RB30 with over 500BHP. Simple solution was to mount the sensor inside the metal pipe itself, job done.
 

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Discussion Starter #15
yes you are correct actually, with an IAT sensor hooked up properly it will account for it.

but i still maintain... the cost is quite a set back.
 

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blow through ??

can't see how this can work. with a mass air flow sensor using a hot wire with the incoming colder air altering temperature on it and thus altering m-v sent to the ecu, why would you want to blow warm pressurised air through it ?
in what way would it take its reading ? apart from the fact that if it broke where would it end up ? on a journey in past one of the inlet valves.
 

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Discussion Starter #17
regal... there is litterally NO DIFFERENCE between putting the maf behind the intercooler and in front of the inlet plenum and having air blow over it or putting it in front of the turbos as per usual and allowing the turbos to suck air over the maf instead. NO DIFFERENCE...

what your not understanding is a basic physical principle.... think for a second... if the air first comes in from the turbos.. its the exact same amount air (mass of air) in the system! its called the IDEAL GAS LAW...

Pressure x Volume = number of moles x gas constant x temperature,,,

number of moles and gas constant are given as like 1.2 for regular air... so it basically becomes.

P x V = T

u can see quite simply that wether its "400 units" of warmer pressurized air... or 400 units of cooler less dense air... its going to give the exact same amount of air.. or "mass air flow"

the principle is flawless sorry but theres no argument on that point.

i hope that clears things up for u.

as for the "breaking and going into the engine valves"... consider this... if you break apart a maf when its infront of the turbos as per usual... consider that not only will it destroy the inlet turbine wheels... but then you'll have pieces of MAF and pieces of turbine going into the motor... compared against the situation you describe of just pieces of screen or plastic at worst going through... id prefer the maf behind the intercooler.


can the person who described the "ease" of hooking up one 80mm maf to the ECU can you please specify which ecu your talking about and the process involved?

thanks
 

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no difference !

oh but i DO understand the principles of air flow. thats was'nt my point.
my concern is "TEMPERATURE".
the hot wire can only work effectively if there is enough of a difference in the heat between the wire and the air going through it.
my concern was that with higher boost levels brings higher temps, enough maybe to max out the maf sensor.
intercooler efficiency would also play a part.

next to that you have contamination. most inlet tracts on turbo cars ive seen had traces of oil in them. detramental to the life and accuracy of the maf sensor ? i think so.
theres a good reason the air filter is before the maf sensor.
heatsoak after shutdown cant be good for it either.

and as for having bits breaking off pre or post intercooler, i'd prefer pre intercooler, at least they have a chance to be caught in the intercooler.
it may very well work,depending on the temperature range of the sensor(what its pre-heated to) but i cant see an air flow sensor lasting any time.
or at least with any accuracy.
anyway too many variables for me.
 

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Discussion Starter #19
hrmm... i have a counter response to all of that except one point.. which may very well make me re-consider... i agree with your point of the oil and residue dirt on the maf being not good. and a solid point you made about the air filters being just before the maf's...

as for the other points... what is also impled by "no difference" is the fact that a quicker moving body of air with a higher temperature than a slower moving body of air at a lower temperature, the quicker hotter air will have the same "cooling" effect as the slower cooler air. therefore cooling the "hotwire" equally the same and continuing to provide accurate readings.

like i said mate, this isnt theory.. i SAW this with my own eyes in full fantastic operation. 2860-5's at 1.8bar on a fully built motor. the guy was running the car like that for 1.5 years alrdy. and he intends to keep it for a long time.

a lot of the guys in australia do a blow through system... it just looks so much cleaner though can't you agree with that?
 

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Frankly if the maf is the issue here then there is none,blow thru setups have been done many time in many ways,just have a look at the ford guys (pick ups and mustangs) most with the lightning maf.
There's many pics on the net of the z32 maf in many iterations being used for this setup,highest setup I saw was just under 600hp,with boost in the 20s and the maf has lived apparently for some 2.5 years like this.
 
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