4" intake pipe with 3.5" gm sensor?

[eclipsefwd]

Hi all, I am thinking of getting a FP3052 which has a 4" intake. I plan on using a S-AFC and MAF Translator to tune with. I have been contemplating the different ways of monitoring the air. Buy a 4" intake and use a reducer to mount a 3.5" sensor on it. Or buy a 4" intake and put a 4" k&N on it then do a blow thru setup with either a 3" or 3.5" sensor. I have the ADFX FMIC with 2.5" piping. I would think using the 3.5" sensor with this large turbo would be better. But a 2.5"-3.5" transition seems a little odd to me. If anyone has any ideas on which setup would work best or has any experience with this kind of dilema please reply. Thanks.

Ryan

 

[nine5raptor]

I will work with 2.5-3.5 reducers. I am running that right now. The problem is, when the air velocity rises (either with engine rpm or boost--I run ~18-19psi on a 14b) the air has a greater tendency to flow through the middle of the sensor. In other words, the no-slip boundary gets larger in the reducers causing the maft to read more air than is actually there, as the heated wires also happen to be near the center of the sensor. This means that I get richer as I go through each gear, not really a problem as long as I am not trying to go full boost below 3000 rpm (wouldn't be a problem for you either). If I do, the way I have it tuned, it is a little lean on the bottom, but great on the top. An afc would also correct this, but I don't have the money or time for that right now.

I would recommend the 3" in blowthrough. Probably what I will switch to, but I just don't have the time to find a new sensor at this time.

 

[eclipsefwd]

Thanks for the reply. I am just worried that a 3" sensor wont be large enough for the turbo I want to get. It flows around 52lbs/min.

 

[nine5raptor]

the maft will tune for up to 1250 cc/min injectors and the 3.5" has been used with a custom maft w/ 160 lb/hr injectors. These should be big enough for your turbo.

One of the members of the yahoo group made over 460whp, but I don't know which maf he was using.

Also, if I remember right, the max for the 3" sensor was ~600 hp and for the 3.5" ~800hp.

Hope these will help a bit.

You should contact Mike Licht @ www.fullthrottlespeed.com

 

[DarthBulk]

I had exactly the same dilemma, and I opted to go with the 4" intake with 4" K&N Filter, then use a 3" GM MAF with translator in a blow-through configuration. I have the FP-3052 turbo, FMIC, and all the piping already, I just don't have everything installed yet. I decided the blow-through configuration with a 3" MAF would be better for my needs...as I will be doing more street driving and not drag racing. I want the fastest possible spool up time...

I can't see the need for a 3.5" MAF in a blow-through configuration, and don't know if anyone even makes a pipe for this. I would guess it would be custom made, if you wanted it...but why?

 

[jdmawd]

Originally posted by eclipsefwd
Hi all, I am thinking of getting a FP3052 which has a 4" intake. I plan on using a S-AFC and MAF Translator to tune with. I have been contemplating the different ways of monitoring the air. Buy a 4" intake and use a reducer to mount a 3.5" sensor on it. Or buy a 4" intake and put a 4" k&N on it then do a blow thru setup with either a 3" or 3.5" sensor. I have the ADFX FMIC with 2.5" piping. I would think using the 3.5" sensor with this large turbo would be better. But a 2.5"-3.5" transition seems a little odd to me. If anyone has any ideas on which setup would work best or has any experience with this kind of dilema please reply. Thanks.

Ryan

just run the flux capacitor in blow through and get a 4" intake. i had dejon tools bend me a 4" CAI similar to the buschur unit. the cost was under 200 bucks here is a pic

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[Omega]

Whatever you do, try to make the dia transitions as smooth as possible. I bought a set of 2.5 - 3" reducers from here which are very well made. They make exhausts for NASCAR as well I don't like the way most of the common reducers are so abrupt. The Dr. Gas reducers are nice and smooth.

If I had the time I would make new housings for the MAF. That way you could bolt a new section to the MAF core and kneck it down to whatever dia is needed. I could do it, but the Al block isn't cheap.

 

[eclipsefwd]

Awesome, thanks guys. I was hoping the 3" sensor would work well in a blow thru setup. That is what I wanted to do because I think it will look the cleanest and be the easiest to accomplish. I am glad to hear the 3" sensor is good for 600hp, thats way more than i will ever make.

 

[eclipsefwd]

jdmawd, that CAI looks great. Will it end up putting the filter in the stock smic location. If you could show me a pic of it installed that would be really helpful. I just may have to call up Dejon and see if they can bend me one of those too. VERY NICE.