My MAFT review....

[NOSLO2PT0]

I'll try to give a quick rundown of the car BEFORE the MAFT went on. Before the MAFT, I had a 2G MAS + 3" intake on the car. These results are with the 2G MAS.

I'm running a 90 GSX, FP Green, 272's, FRH manifold, IRC FMIC, Supra TT pump, AFPR (45psi base), 660's, and an AFC. Those are the major mods. I had the car decently tuned the day I went to the track. It was 60 degrees, I was running 22psi on Shell 93 octane. Car was reading about 9" of vacuum, which is where 272's should be. I consider the car being pretty well boost leak free, according to the gauge, even tho I didn't leak test it.

I ran out of time at the track, but ended up pulling a best of 12.27@113 as read HERE .

Well, about 2 weeks after I made these runs, someone decided they wanted my gauges and intake setup more than i did. So, I put the car back together with some old gauges I had laying around, and had to install the MAFT (due to not having the 2G MAS anymore).

My first problem I ran into was getting the couplers OVER the LT1 MAF (3"). This proved to be a major PITA. After sticking the MAF in a vice, the couplers in the microwave, lubing them up with dishsoap, 4 hands, 2 screwdrivers, and a LOT of swearing, we finally got the couplers on. Tightened up the T bolt clamps, and installed it on the car. After driving the car home (about 1 mile), I noticed the coupler AFTER the MAF seemed to be pulling away from the center of the MAF just a bit.

I decided to set the MBC to 21psi just to see how the car would react. Middle of 2nd gear, POP!! Off comes the coupler. Luckily for me, it was stretched out enough I could get it on by myself. But no matter how tight I made the Tbolt clamps, the coupler always wanted to slide off. This was due to the air flowing thru a 3" opening, then hitting the reducer where it necked down to 2.5". This made the air push against the coupler and push it off the MAS.

I drove teh car from Chicago to the Shootout in Ohio like this, without ever hitting any positive boost. Anyways, we get to the hotel, and the damn coupler is barely hanging on. So I said "I'm gonna fix this is PERMANENTLY!!" I went to Wal-Mart, got a drill, some #8 1.5" sheet metal screws, and drilled a hole right through the Tbolt clamp, the coupler and teh MAF. I then screwed a sheet metal screw through all 3 of them!! So far, it's held and hasn't moved

Anyways, the fuel trims I did have trouble dialing in. I set the base to 660's, then set the idle, mid, max to -15%. The low fuel trim (idle) is still a bit lean at 114%, the mid is dead rich at 81%, and the max is very lean at 117%. The AFC I have is no more than -3% at any given point.

Now for the track results!!!!! Keep in mind, this is with basically NO tuning. I finished teh MAS install/fix at 2a Sat. morning. Went to bed, woke up, drove to the track, made my runs. Unfortunately, when the people stole my intake, they took the ENTIRE intake tube as well. So I basically had to run a screen over the inlet of the turbo. So I was sucking in 150 deg. air directly off the radiator/fan. That coupled with the 21psi and the really crappy 92 Speedway gas I was running, it was gonna make for a slow day at the track.


My very first run of the day, I went 12.35@111!!! WHOA! I'm only .08 sec. off my best time with the other setup, on lower boost, hotter air, and crappier gas. However, that was to be my best run of the day. My O2's were a bit lean (.88V) and I had really low timing on the top end. In order to get more timing up top, I would have to lean the car out, which I couldn't do with the AFC, since that would make me run even leaner. I tried to take out another 5% of fuel with the AFC, but the car knocked real bad. I only ran 12.38@110 trying this. I didn't have time to go bump the MAFT up another 5% richer, then see the results.

I ended up running mid/hi 12.30's all day on this setup. When I got to the hotel, I hated this MAFT. I had NO clue how to tune, where it would be at, how it would run. Now seeing I was only .08 off my best time even with all the other conditions, I'm somewhat pleased. I didn't notice any spool up diff. noly because I haven't tried to pay attention as to when it spooled up. The local cops didn't care for us winding the cars out in 3rd gear around town.

I fully expect once i get my rear end fixed (broke an axle running 26psi/116 race gas), putting an intake tube on to get some cold air into the motor, and running some good gas, I should see my 11 sec. pass on pump gas and a full interior.

I'll keep everyone updated. Anyone have any questions, please feel free to ask.

Thanks,
Mike

 

[RipperXX]

I would seriously like to know what you run after you get the intake setup right again.

And I would seriously want to kick some a$$ after haveing my crap stolen. (I carry a small wood bat with me in the car everywhere I go)

Although that wont help any if im not there to use it :/

 

[NOSLO2PT0]

MAJOR UPDATE!!!! Using my last set of adjustments, Base: 660, idle: +5%, mid: -30%, max: -10% (all these were used trying to get my fuel trims to 100%), the car ran like complete shit around town.

I did some research and read a bunch of threads from various lists. It turns out, the Translator reduces the airflow value so much at the 660 level, that the ECU gives the motor way too much timing advance (even part-throttle). So, the car would basically choke on it's own timing advance. I 0'd out the AFC again, reduced the base to 550's, and 0'd out the translator dials as well.

After a night of driving around, here are my findings. The mid/hi fuel trims are hovering around 103-108%. The low fuel trim is still pegged at 118% (1990 car, max value). AFC is 0'd out on lo throttle. I'll have to raise the idle knob on the Translator a few clicks to remedy this.

Now for the WOT tuning! I opend the car up at 17psi. As soon as I hit 4k, the car fell flat on it's face, sputtering, and missing badly. So, I figured it was kinda rich, since the Translator is set on 550cc's. I take out 5% across the board. Same thing, sputtering, missing. Take out another 5%. NO change. Take out another 5%. The car cleared up a little, but still had some miss in there. I took out ANOTHER 5% (now sitting at -20% across the board onthe AFC), and the car ran like hell!!!! Car was pulling very hard at only 17psi, 25 deg. timing up top.

So, once I get the intake pipe done, I'll take it to the track and try a few more 22psi runs to see if i can better my 12.27@113 run. I'm fairly confident I can.

I'll keep everyone posted.

Mike

 

[stockmkt8r]

Must feel good to know that you could take out a ferrari at anytime during the day and probably more reliably too.

hehe, good luck bro.

 

[greathuskie]

i dont think his car is more reliable than anything, remember its a DSM

 

[DSM mechanix]

Originally posted by stockmkt8r
Must feel good to know that you could take out a ferrari at anytime during the day and probably more reliably too.

hehe, good luck bro.

:laugh: :laugh:

 

[NOSLO2PT0]

UPDATE. I hit the track last night, armed with 23psi, 93 octane in the tank and a good shifting tranny. Keeping the same MAFT settings as above, I began tuning the car with the AFC. Starting at -15% across the board, 1st run was a paltry 12.60@108. As the night went on, I kept going leaner and leaner and slowly getting quicker and quicker. By the end of the night, I had set a new personal best (but didn't reach my goal) with a 12.21@112 on a 1.68 60'.

The MPH wasn't where it should be, but the ET was much quicker, probably due to better driving/shifting. I really think a boost leak in my biggest culprit in the loss of power on the top end. My timing would really drop in 4th gear. If I richened it up enough to clear out the knock in 4th, my 1/8th times got worse due to loss of power in 2nd and 3rd gear.

I'm going to have to do a boost leak test on this thing to find out where the airflow is going. Because i'm seeing 2800Hz on the AFC, and that's REALLY high, even for 23psi.

Oh well, that's my update for this week. Stay tuned, as my 11 sec. pass on pure pump gas and stock ECU/AFC combo will materialize one day.

Mike