Custom large tube MAF sensor for TPI
08-14-2008, 10:13 PM
#1
Registered User
Thread Starter
Join Date: Jul 2007
Location: Pittsburgh
Posts: 353
Custom large tube MAF sensor for TPI
I just wanted to share alittle creation i made that probly has been done here before as its been done over thirdgen a few times.
Basically i got a pretty hot 383 that was breathing thru stock1989 camaro 2.8" ID MAF sensor and camaro TPI air lid. Pretty restrictive stuff or atleast it looks that way. Its said stock MAF without screens will flow 650-700 cfm depending where you read it
My 58mm TB is suppose to flow near 1000 cfm so obviously the air intake tract is the restriction.
Does my 383 need more air? I think so. I made about 400whp at 6300 rpms thru the stock stuff and old dirty k/n filters and i expect more in it. how much more? i can see 20-30whp depending but we'll see
Not wanting to change to speed density i decided to try to make my own MAF sensor and CAI setup.
I decided 3.5" pipe will flow enough for this car and fit my engine bay. I bought some bends and some 3.5 silicone couplings. For the TB attachment, i got a 4" to 3.5" coupling and it works well enough on my 58mm holley TB
For the MAF sensor i took my stock unit and cut the bottom guts out. cutoff wheel and carefully worked around the plastic housing and slowly cut all the top housing off. i took a section of 3.5" pipe and cut out a square/rectangle out the bottom to insert the old MAF guts into. I used quicksteel epoxy putty to hold the guts in the tube, and sealed it all off around the seams with clear RTV silicone
Heres pics
At the end is a 3.5" by 5" cone style AEM dryflow air filter
FUN PART:
It works so far but you will have to make extensive changes to the MAF tables/scalars to get this to work. I had my tune pretty good before hand and with this mod, my car wouldnt even start up on the first try with that tune! i slowly increased scalars till i got it to start and hold idle but it was lean.
AFter increasing all the scalars up a LARGE amount, i got it to somewhat run ok for the most part. Started fine tuning it by going into the actual tables and working the values in there. Still aint perfect but its my first real day of tuning it. I run open loop by the way so its easier to tune. I got some slighly rich spots and some spots that are still very lean but its getting there and is showing signs it will work just fine
I did notice my WOT midrange AFR has gone from 13 to 16 to 1 now. granted the highest end of the MAF tables are not quite right yet, the old MAF was maxed out before and Power Enrichment mode is taking over the tune. I will have to finalize that upper end MAF table and then work more fuel into the PE tables
This means this car is taking in a TON more air and is liking it! I expect a good gain with this mod on this motor. I hope 20whp atleast
Basically i got a pretty hot 383 that was breathing thru stock1989 camaro 2.8" ID MAF sensor and camaro TPI air lid. Pretty restrictive stuff or atleast it looks that way. Its said stock MAF without screens will flow 650-700 cfm depending where you read it
My 58mm TB is suppose to flow near 1000 cfm so obviously the air intake tract is the restriction.
Does my 383 need more air? I think so. I made about 400whp at 6300 rpms thru the stock stuff and old dirty k/n filters and i expect more in it. how much more? i can see 20-30whp depending but we'll see
Not wanting to change to speed density i decided to try to make my own MAF sensor and CAI setup.
I decided 3.5" pipe will flow enough for this car and fit my engine bay. I bought some bends and some 3.5 silicone couplings. For the TB attachment, i got a 4" to 3.5" coupling and it works well enough on my 58mm holley TB
For the MAF sensor i took my stock unit and cut the bottom guts out. cutoff wheel and carefully worked around the plastic housing and slowly cut all the top housing off. i took a section of 3.5" pipe and cut out a square/rectangle out the bottom to insert the old MAF guts into. I used quicksteel epoxy putty to hold the guts in the tube, and sealed it all off around the seams with clear RTV silicone
Heres pics
At the end is a 3.5" by 5" cone style AEM dryflow air filter
FUN PART:
It works so far but you will have to make extensive changes to the MAF tables/scalars to get this to work. I had my tune pretty good before hand and with this mod, my car wouldnt even start up on the first try with that tune! i slowly increased scalars till i got it to start and hold idle but it was lean.
AFter increasing all the scalars up a LARGE amount, i got it to somewhat run ok for the most part. Started fine tuning it by going into the actual tables and working the values in there. Still aint perfect but its my first real day of tuning it. I run open loop by the way so its easier to tune. I got some slighly rich spots and some spots that are still very lean but its getting there and is showing signs it will work just fine
I did notice my WOT midrange AFR has gone from 13 to 16 to 1 now. granted the highest end of the MAF tables are not quite right yet, the old MAF was maxed out before and Power Enrichment mode is taking over the tune. I will have to finalize that upper end MAF table and then work more fuel into the PE tables
This means this car is taking in a TON more air and is liking it! I expect a good gain with this mod on this motor. I hope 20whp atleast
08-15-2008, 09:09 PM
#3
Registered User
Thread Starter
Join Date: Jul 2007
Location: Pittsburgh
Posts: 353
yeah i may paint the MAF black to match the other parts but this was just a quick mod to see if it will work well and if i think i will gain power
if i do hit 20-30hp out of this mod which is possible based on how much the a/f changed that will be NASTY!!
420-430whp 383 is awesome for me. That should put me near 10 second 1/4s in the winter air and solid launch! atleast over 120mph traps in the warm air
tomorrow i clean the car, do a buff/wax job and continue to tune the top end. hopefully if feels better. i cant wait
if i do hit 20-30hp out of this mod which is possible based on how much the a/f changed that will be NASTY!!
420-430whp 383 is awesome for me. That should put me near 10 second 1/4s in the winter air and solid launch! atleast over 120mph traps in the warm air
tomorrow i clean the car, do a buff/wax job and continue to tune the top end. hopefully if feels better. i cant wait
08-17-2008, 05:52 PM
#4
Registered User
Join Date: Sep 1999
Location: MI
Posts: 2,342
08-17-2008, 07:55 PM
#5
Registered User
Thread Starter
Join Date: Jul 2007
Location: Pittsburgh
Posts: 353
lol well i been working on the upper MAF tables and after changing them alot my air fuel dropped considerably down to the 13-14.0 range in the midrange. looked to be heading near 13.0 or so at the upper rpm range but i havent tested it all that much yet. Tomorrow will be that day.
Since i didnt have to change PE mode much yet i'm now not sure how much this may have given me. Granted i havent quite been over 6000 rpms yet, i sure hope i've gained alot more power out of this especially in the mid range.
Since i didnt have to change PE mode much yet i'm now not sure how much this may have given me. Granted i havent quite been over 6000 rpms yet, i sure hope i've gained alot more power out of this especially in the mid range.
Thread
Thread Starter
Forum
Replies
Last Post