As discussed elsewhere - I would really not recommend using the MY99/00 hot film MAF in a blow-through configuration!

Cut the flange off the Q45 MAF and put the hose straight onto the housing.

Andrew...

 

More news guys...

Good advice from AndrewC regarding chopping the end of the Q45 housing off to avoid having two parts being bolted together althought i must admit i did feel a bit when i was chopping it in half!

Right, back to the point. Firstly the reliability has gone up to 100%. No problems at all with water, mis readings, etc. But, as i guess you probably have worked it out - the ariflow readings (voltage) from the q45 have gone up. And quite considerably. Previously i was seeing around 4.55 volts at wot (2nd gear only). But now, im seeing a peak of 4.8 volts! this is obviously due to the lack of pipe before the maf element to allow the air to fill the larger tube. One good thing though, the car drives much nicer and feels much more responsive and crisp. No map adjustments i did before could seem to bring the crisp throttle response that i have now. So, in a way its kinda good for now, but im a little worried about the peak voltages im seeing. What do these mafs max out at? is it 4.96v ? anyone know?

I have some logs if anyone wants to see some graphs.

any other ideas? AndrewC ? p.s thanks for the ideas/interest

 

just saw 4.92v this morning coming to work....

 

The MAF will read upto 5.115v on a powerFC, 4.9v is actually quite a way from that in airflow terms although it does seem a bit high for your power level.

Do you have a photo of the setup now? Do you have a sharp increase in pipe size immediately before the MAF element?

Andrew...

 

ive got a tdo5 18g and ive been told that i need a z32 maf in 80mm diameter form. This bolts straight in the original place. The only mod is the plug which needs splicing into the original loom. Ill keep you updated. Will be doing this in the next 2-3 weeks hopefully.

 

Z32 bolts straight into place on an early (MY92-096) car, not into a MY99 which has a 90mm MAF housing.

It's no coincidence that the MY99 powerFC has an airflow option for a 90mm Nissan MAF

Andrew...

 

is the 99 housing not 80mm?

i thought the v3/4 sti/wrx was 90mm and the v5/6 = 80mm

 

Its basically the 2.5" diamater pipe of the fmic is now too close to the element - now the end of the maf tube has been chopped off. The pressurised air simply doesnt have enough time to fill the volume of the 80mm inner diameter pipe of the maf housing and slow down its speed respectively.

You're right though, 4.93v is too high for 1.45 bar. On a typical 80mm MAF (inside diameter ) i would expect around 4.75v ish.

I have bought a 90mm aluminium short tube and a few adaptors/ jubilee clips etc and am going to increase the distance the smaller fmic tube is from the maf element whilst at the same time keeping the reliability ( hopefully! ) i think this should work. then i can finally finish the map off...

if the stuff has arrived this evening i will post up some pics etc. but should be done by friday latest.

I will get this to work....

 

StickyMicky,

the internal diamater is 80mm and external diameter is 90mm on a my99
the Q45 maf is the same.

 

CLICKY

 

how cud i do this with a z32 maf ?

would i need a remap tweek too

thanks ste

 

Going back to the days of carburettors, I used to get carb icing due to the cooling effects of the airflow on the body of the carb. This caused fuelling problems and erratic running, but when trying to investigate the ice would have melted away. This could be what is happening with you, when on boost the airflow is causing the aluminium tube to cool so a layer of frost if not ice from the moisture in the air forms but once at low flow latent heat melts it leaving moisture in the MAF tube and beyond. Possibly

 

any update on this project

 

well im back on suck through standard position now. What i really proved was to do this succesfully you need a bespoke blow through maf housing made and designed to accept the maf chosen. Using pieces of silicon and various reducers and cut maf tubes just proved to be too fragile.

At the moment i have tuned the car to the best of my ability at around 1.5bar ready for the rolling road day at prosport (gulp!) so im going to leave it at that for the time being as its running well. But after that i have another plan.. as its very hard to get hold of blow through mafs ( or atleast pretty expensive ) i have decided to run mafless with an Apexi ECU!!!!

The way im planning on doing it ( or atlease giving it a try ) is with the following : AEM FIC. Its a fuel / ignition controller from AEM which can do much more than i will be expecting from it. Its general use is for turbocharging non turbo cars whereby you can set up fuel and ignition retard tables. BUT it has a built in MAP sensor / takes RPM signal from the crank.
and had the ability to output a MAF simluated voltage (another user adjustable map which can be uploaded to it ) so therotically with the use of an intake temperature sensor on the Apexi to control fuelling i can simply remove the MAF and feed the ECU with the simulated voltage..

thats the plan anyway and i will certainly update this thread when i get to it. After feb 1st sometime (if my car is still intact after the rolling road!!!)

tbc..

 

Ever heard of a MAFSIM ;-)

 

i have indeed..

just not sure of...
price? / where to buy? / reliable ? / Programmable ? / Support? /

 

i was going to suggest mafsim lol

 

AndrewC can sort you out a mafsim AFAIK...

I got to be honest though, blow through works perfectly fine for me, and I also did a fair bit of 'question asking' before I tackled it and came up with this..



As long and straight a pipe as possible, with the ID circa 73mm, using a newage MAF..

 

Quick update, had it on the rollers today to see what its making. It was run in 3rd gear (?) and only made around 1.3 bar of boost but i was very happy with the result. There is a little bit of fuelling that i need to sort out but apart from that pretty pleased. Maf in standard position btw

 

Just bringing this thread back from the almost dead.
I am currently trying to make my My98 with 2.15 engine in it BT MAF.

Only problem I have is with the lines that were connected to the original inlet tube, like the Idle Valve, DV return and some other ones.

Where do they go now, do I reroute them to the IC charge pipe Post MAF, or do I fit them to the hose/pipe going to the Turbo (like standard)

Thanks in advance.

 

Idle control feed must be post MAF, DV input must be pre MAF, DV outlet can be recirc or VTA, will not affect MAF.

For information, I run the STIv7 MAF in BT with a 65mm ID pipe, maxxes at approx 380HP

 

Only 1 more thing.

The idle control feed is on the manifold, as the Idle control valve is bolted on there.
What do I do with the hose coming from the idle valve, which goes back to the stock inlet (post maf).Keep it there, so that it is pre MAF on a BT setup, or do I plumb it into the IC piping leading to the tB (Post MAF), as that way on boost he the idle valve gets pressurised???

 

You plumb it into the FMIC pipework post MAF, yes it will see pressure.

If you leave it as is (pre BT maf) the ICV will draw unmetered air in and the car will stall. Trust me lol

 

Thanks fot the advice.

 

Back from the daed lol. Will the ICV be ok seeing boost?

 

No issue at all