When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The analysis continues I keep comparing to past logs and I came across a very close match.... 1psi difference and it every so slightly shows in the power graph, but otherwise a near perfect match!
Red line: current (stock) MAF in 85mm housing, stock MAF scale, 13psi
Blue line: previous Amazon MAF in 83mm honeycomb housing, modified MAF scale in idle and cruise regions, 12psi
Last edited by slash128; Oct 20, 2016 at 04:46 PM.
There's a subtle trend in the above graph that leaner AFRs appear to give comparatively better power. I've noticed while tuning my car that the difference in power between AFR of 10.5 (and below) and 12 is quite noticeable. Perhaps this accounts for a small part of the variation you're seeing.
Perhaps your old MAF had more internal resistance? You could do the resistor mod to get more head room. The main thing is that your AFRs are looking safe, and you've got enough headroom for more airflow.
There's a subtle trend in the above graph that leaner AFRs appear to give comparatively better power. I've noticed while tuning my car that the difference in power between AFR of 10.5 (and below) and 12 is quite noticeable. Perhaps this accounts for a small part of the variation you're seeing.
Perhaps your old MAF had more internal resistance? You could do the resistor mod to get more head room. The main thing is that your AFRs are looking safe, and you've got enough headroom for more airflow.
I chalked up the slight difference in part to the 1psi boost difference and also simply due to various variables, both with the car and environmentally, as the previous log was in June and now it is October and weather has changed significantly. The big takeaway for me is how much even a few mm can alter the MAF reading, oh and to measure things lol... The honeycomb MAF housing was listed on eBay as 89mm OD. I figured with a wall thickness of 1 to 1.5mm it should have an ID of 86 to 87mm. I was quite surprised when I finally measured it yesterday after 2 years that the wall thickness is 3mm and the ID is only 83mm. I am not so worried about the headroom to go the resistor route, just yet... But I have been eyeing my MS CAI housing and considering hacking that up since it is a full 86mm...
The gain in power from 10's to low 12's AFR is precisely why I was having so much fun with running E50! I was working my way towards best torque AFR and it was paying off, but sadly the only local station that carried it decided to discontinue it earlier this year and never brought it back. The only reason I run as rich as I do on 92 octane is to counter knock. Our 10.0:1 compression engines are great for NA power but become severely knock limited under high boost...
It's good to be back I no longer have any doubts about my rebuild!
FWIW, this is with the stock MAF sensor in the 85mm housing, no honeycomb, just a single screen. In the 83mm honeycomb MAF housing with a single screen this sensor was hitting 4.94V @ 12psi. In the 85mm housing it only hit 4.89V @ 14psi... Amazing what a difference 2mm diameter makes...!
Last edited by slash128; Oct 21, 2016 at 07:13 PM.
Working on a home-brew GoodBox/RxDuino for S1 gadget... Not sure how far I will get but I enjoy this stuff. It will make a nice project for the coming winter months when snow keeps the car in the garage...
Yep, the GoodBox and Paimon's work is what inspired me. I have no grand plans to produce anything, or even if I will be successful with what I'm after, just a personal pet project...
I keep comparing to past logs and I came across a very close match.... 1psi difference and it every so slightly shows in the power graph, but otherwise a near perfect match!
