Relocation of the MAF in the charge piping Q's

[Keyan]

I got couplers in the mail so I'm all set to install the MAF in the charge piping right before the 5th injector elbow...

my question is this: will my unichip require a retune? Will my car be safe off-boost without having to monitor AFR? The way I see it, the MAF is still going to be reading the same amount of air passing over it, altho before the turbo it's just not pressurized. The Air Intake Temp will be higher, and more accurate, so off-boost thorttle response should be better (its pretty bad right now), but maybe with the higher intake temp the ECU will lean out my injectors and I'll run a little bit more lean (maybe .1 or .2 AFR)? I'm going to be buying a AEM UEGO -eventually- but can I get away with the relocation right now without a unichip retune?



Thoughts please?

[yamaha]

When I was running a lower boost number, 8-12psi, the MAF would read up to about 2psi, and then my turbo box would kick in. You should be completley fine withit in the chargepiping before the throttle body, alot of people run it this way and you should notice some vast improvements.

[Keyan]

that's what I'm hoping. If anything, the MAF will max-out the voltage quicker throwing the ECU into open loop sooner, thus making it a little more safe. I dunno. I'm gonna put it all together on thursday most likely

[yamaha]

Regardless, off boost driving should be much better, if you come to Pittsburgh in May, maybe I'll let you drive the RD to see what it feels like. :)

[evan938]

youre a *****. you still havent let ME drive the rd.

[Keyan]

youre a *****. you still havent let ME drive the rd.

aaaaaahahahahaa evan got pwn'd

[bmxdad]

So, why is it better to put the MAF near the TB and under boost, then in front of the turbo like most do?

[KeWLKaT]

So, why is it better to put the MAF near the TB and under boost, then in front of the turbo like most do?

Eliminates the need to recirculate the BOV and also more accurate readings of the actual flow along with the temperature going into the manifold.

[bmxdad]

Any negatives?

I'm close to finishing my setup and was going to do the normal route by keeping the MAF out of boost ... but this keeps coming up ... who all is doing it this way??

[Denisst99]

i'm doing it that way
i even think i was one of the firts to do it

anyway, i've got much better results with a boosted maf then a vacuumed maf
regular driving is better,boosted driving is the same (when properly tuned)

[Keyan]

nice, its good to know there are no negatives to swapping the location of the MAF.

Maybe i'll do it today instead of thursday :)

updates and pics to come.

[KeWLKaT]

wow a pic of a sensor in piping, i can't wait.....

[Keyan]

wow your comment is so sarcastic I don't even have a comeback for it. don't make me make a video of you like ugzz did.

[KeWLKaT]

I would love to see that, lol. Famous or infamous, I'll take it as long as it's advertizing, haha.

[dmdicks]

The Unichip will require a re-tune to work properly in a blow-thru configuration. Also you need to be carefull of air surging back into the MAF after bouncing off the Throttle body plate with anything below WOT. This and the fact that the air is more dense will cause erratic MAF readings. Another thing to consider is the BetaII ECU has the Intake Air Temp sensor with the MAF so its going to be reading the hotter charge air then the Ambient from the Turbo intake side. This will cause the BetaII ECU to add more fuel and restard more timing than usual. Without a Unichip tune to compensate you will probably be running even more rich and have less total timing. All that equals less power.

[Keyan]

The Unichip will require a re-tune to work properly in a blow-thru configuration. Also you need to be carefull of air surging back into the MAF after bouncing off the Throttle body plate with anything below WOT. This and the fact that the air is more dense will cause erratic MAF readings. Another thing to consider is the BetaII ECU has the Intake Air Temp sensor with the MAF so its going to be reading the hotter charge air then the Ambient from the Turbo intake side. This will cause the BetaII ECU to add more fuel and restard more timing than usual. Without a Unichip tune to compensate you will probably be running even more rich and have less total timing. All that equals less power.

your post makes no sense. how is the air more dense? once it hits positive pressure the MAF maxes the voltage and the car goes into open loop, ignoring maf values. plus HOTTER air = LESS oxygen = LESS gas is required = LEANER. PLUS I don't see how the air will surge back into the MAF because I'm going to be locating it back to its OEM position next to the coil packs. you are saying the oem position is wrong?


please explain? :confused:

http://img.photobucket.com/albums/v162/Keyan/mafchargepipe.jpg


here's how it looks.

much better throttle response (almost identical to when i was n/a) so I'm happy with that. I'm kind of afraid of going WOT, but it should be safe because the unichip t-module takes over when boost hits, right?

[Denisst99]

if you're running athe same tune in your unichip then yes you might be off a bit in some spots
mostly poart throttle and cruise, WOT should be very similar
air temps will read a bit higher,soi base ignition timing will be lower a bit
never had much problem airlfow wise

for the surging ,if the BOV is very close to the maf then yes it MIGHT cause issues,but rarely something bad

[yamaha]

You should be ok like that Keyan. I have my MAF almost at the same spot, but the blow-off valve another six after the MAF.

[KeWLKaT]

Keyan your logic is flawed.

By density he means the amount of air weight per volume... If it is compressed, it is obviously more dense than at atmospheric pressure, lol.

Peace out, no hard feelings.

I'm not saying it won't work, just correcting your physics.

[Keyan]

well, i was thinking that the density = psi and since the MAF sensor is really a "speed density sensor" that it could read it fine and adjust accordingly. but i dont know physics so don't blame me lol.


and a dumb question but higher intake temps means the ecu will retard timing right? and retarded timing means less power but is also safer right? (ie: i'm not walking into the danger zone with this mod, am i?)

[dmdicks]

The car will run because the Unichip bases on when to fire the subinjector off the Turbo Module's map signal. However, the MAF also gets modified a bit to run the 290cc primary injectors and this is what will be off.
You can run a blow through config but if you have problems going into the change then most likely you'll still have problems. It really depends on how good your tune was to begin with.

[Keyan]

well i got my kit used from a member who said YOU personally tuned it sooo you tell me, how good is the tune lol.

[Cypher]

and because Dave is going to ask, Keyan has AJ's (sequin22) old kit.

[dmdicks]

Hmm...AJ's kit. I can't remember. Didn't he start out with a entry level non-decompressed? And then added the 290cc injectors later? I'll have to look up his tune. If I did it then it should be at least better than Alpine's base tune. It's never really fully tuned though without getting a custom tune on the dyno.

[Keyan]

its a stg1 kit with a 13g instead of a 15t.

i've gone WOT since the conversion and it seems to be holding up fine, but you can tell i've lost power with pulled timing. time for a retune FTMFW

[dmdicks]

You can try getting and IAT sensor from a V6 and using that instead of the one in the MAF.

[Keyan]

a retune i think will be easier than custom locating a IAT in the intake piping before the turbo, and hoping the values it produces are the same.

[BColeman]

Honestly, having the MAF as a blow through in a turbo set up is the best option because of the lack of tunability we have at the moment. Of course, you can pop the hood on any boosted JDM vehicle, that came OEM with a MAF, and find them located on the vacuum side of the equation. But those cars have significantly more options for tuning.

Also, just a suggestion. When you have maxed out the tunability of the MAF, then you have to increase the size of the MAF. You could keep it in the Hyundai family by upgrading to the V6 Tiburon one. Or, you can do what a lot of tuners do, and that's use a Mustang GT/Cobra MAF unit.

Of course, I always relate to struck1181's car, because that's the one I've got the most experience on. We started out as a blow through, went to the vacuum side, and are now back to the MAF being a blow through. There are pros and cons to both, but dyno testing and seat time have determined that the best option as of now is the blow through way. When other ECU tuning abilities make there way to the market, that may again change.

Keyan, I think it would be best for it to be blow through for the time being.

[Cypher]

You can't just slap in another MAF sensor and expect all to be well. You must correctly scale back the signal so that the ecu doesn't freak out. I'll write up something more on it later when I have time, I have to go out to the UPS store before it closes to ship out Keyan's axleback (yes buddy I'm finally getting off my ***)

[BColeman]

I'm well aware that you have to do that. That's why I suggested staying in the Hyundai family, because you may not have to change anything but the sensor. But then again, you may have to. At this point, because I haven't seen it done yet, I can't say exactly what you'd have to do.

Throwing in a Ford MAF, for example, requires some extensive tuning to be done. Again, that's why it's important to wait on these things until a proper ECU or standalone becomes available to allow these changes.

I'm sure the reflash that may or may not be available in the near future might handle the change over to a V6 Tiburon MAF. But that remains to be seen at the moment, until the said reflash comes available.