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Discussion Starter #1
The other day I was reading an older copy od Sport compact Magazine, and the guy in it put a turbo on his early 90's SE-R sentra... The thing that struck me as odd was that he did it with a blow thru style set-up (i.e. the airflow meter was after the turbo)...

I was wondering if perhaps that would help with the fuel delivery at all, or if it was simply a matter of easier plumbing for a Fuel injected car...


and before it gets said, I know the term blow-thru is generally reserved for carberated forced induction, but it was about as close a term as I could find...
 

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No problem on the term thats what everyone calls it. I dont think our type of AFM would work well as a blow through setup but I dont really know.
 

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Just a few rambling thoughts.I can think of 2 possible reasons.

1.Convenience in that tiny ass engine bay :lol:
2.Some how the fuel delivery is based on air temp at the AFM :?:


With your spit second AFM,it probably doesn't make a difference.The flapper on the 5m would Probably freak while coming off boost :shock:

I have seen some pics of this setup once also.Now you made me think about it :?: Damn ya anyway :D :twisted:
 

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Greddy Twin Turbo 5MGE

Isn't it there is a set-up on a Greddy Built Twin Turbo 5MGE that has done this blow-thru AFM... the only difference is that the AFM is built for the twin turbo application...

I know I have seen that pic somewhere???
 

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It makes sense to me, if you had a blow-through with an extra injector controller that had equal injector flow to the stockers you could have it controlled precisely by pressure added vs rpm. This would allow the ecu to not be bothered by the boost. I dont think I'll be the one to try it, though it sounds good in theory.

--BillyM
 

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There are a few advatages to blow thru MAF's (which that sentra and many DSM's/Nissan's do) One is obviously for convenience of space, and the fact that you can basically put any type of intake on the turbo (ie-CAI). Another good thing about them is the seem to be much mroe accurate when mounts cose to the TB. The air temp the maf's usually read in a puller is not ever even that close to what is actually going in the TB. When I did this conversion on my DSM, i read the intake temps right before the maf (whcih was in between my BOV and TB) and in the intake manifold and the temps were only about 3-6* in difference on most occasions, as opposed to the pull through which would normally read anywehre from 10-40*off all the time. Now this took a while for my longterm fuel trims to adjust, but once they did the car just ran smoother period Another advantage/cool part is that you can mount the maf in between the BOV and TB, which will inable you to vent the bov with NO ill effects what so ever. Some people like to do this, but we all know what happens to cars with pull through mafs/afm's that try to do this....
 

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Discussion Starter #7
Hmmm... the wheels are definately going here...

Austin, so by what your saying then, theres no richness or throttle studder if I mount the MAF between the BOV and the TB... I'm guessing thats because the airflow stops movingand the BOV is venting the air that is coming from the IC towards the TB...at least until the compressor stops pumping... Wouldn;t you end up going rich when your coming off boost (like when your coming to a stop)tho, maybe even causing it to stall?, The MAF would sense the movement of air, but not realizing it is actually moving backwards away from the TB to the BOV? Logic tells me it would, but if the DSM'ers are doing this, then there hasta be a reason that its not the case...
 

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fwiw, and i don't know much... on turbo dodges the original suck-thru throttle body absolutely fucking sucked. changing it to a blow through completely chagned how the car responded.
 

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Bob,

Absolutely not dude... The gains from mounting the maf between the TB and BOV are negligable if yoru settup isnt really going to take advantage of it. The 2 main are that you can get any intake you want to the compressor inlet and that the air temp/measurment is MUCH more precise as opposed to trying to measure it before it gets squished to hell by the turbo/heated up/and goes through any type of pressure drop...

When yoru coming off boost or w/e you are not really moving anything, its called vacuum (not that you dont know that :D ), but the maf will nto be counting anything. Its very smooth throttle response compared to pull through IMO. Oh and the air that it vents is exactly as you said. The maf has not counted the air that is being vented as long as its place upstream of the BOV...you will not encounter any stalling/hesistating/rich issues when mounted this way...
 

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Discussion Starter #10
Austin... thanks a ton for the info :) You've started my wheels moving again on some ideas...

Slip... I had a Turbo Lebaron, and yeah..it was a total dog like ya said... wish I had known that then, else I may have kept the car...
 
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