I've come to the dark side and gone single, and after my initial impressions, I'm never going back. I'd like some validation (by experienced folks like Wargasm, NoCab, ErnieT - if you don't have a single and I don't recognize you from the last two to three years, don't both cluttering the thread) on my initial observations to make sure things are 'right'. Mods are standard t04s w/ 60-1 wheel, 550/1300s (actually they flow 1350 per RC, but I have the PFC settings at 1300 w .04 lag diff), PFC w/datalogit, TechEdge wideband, street port (maybe an agressive street port - they got a little exhuberant with the porting tool), dp, resonated mp, and cat-back, Twin-Power, 9's for plugs), Walbro pump. My sec. transition is set to 40% at .98 ms.

Observation 1 - ****, this thing flows. What the f? have people been talking about with single turbo lag? The technology has come a long way - not a real difference between twins and this when everything is opened up. Underhood compartment temps are WAAAY down. Can't wait to add a vented hood to complete the package. More of an observation - don't need advice or comments here - see 2 through 4.

Observation 2 - N/A afr's running richer below n10 (~4000 rpm). Due to porting? N11 and above running roughly the same afrs. Shooting for 13.5 afr's in n/a area under throttle and stoich 14.7 under low load/cruise.

Observation 3 - boost areas running WAAY leaner than my custom twins. I'm trying to work my way up from p11 to p17 one row at a time by using some long gradual hills to hold boost and slowly raise rpm (poor man's dyno). I've got very tame timing compared to the other maps I've seen (tame like Wargasm's vs. a few others - thank you for sharing, Brian), and I'm not going to change that until I have my EGT in (waiting for 60mm tri-pod setup) and am on the dyno. I've not gone over 5 lbs of boost for more than two seconds. AFR's jumped up a good .5 to .7 from p11 to p13 over what they used to be with the twins. Is this expected? I assume yes due to improved flow, and now I can understand why some guys have said the 1300s don't cut it and they wire up 1600 w/resistors and/or 850 primaries when they get up in boost. I may have to do the same thing - I'll watch my inj. duty cycles and if/when I hit 85% I'll stop raising boost and get more fuel.

Observation 4 - afr's when temps are very cold (for my neck of the woods) say around 7 deg. C, jump up dramatically (a full 1.0 in some cases). Assume this is air temp corr. factor related? When temps go above 25 deg. C things go back to more what I'm looking for. My air temp corr. settings for the temp ranges I believe are the stock settings:

80c = .957
50c = .984
30c = 1.012
10c = 1.055
-10c=1.102
-30c = 1.148

Have others had to raise up the -10c, 10c, and 30 c areas to compensate more and smooth out afr's over wide temp ranges (we get those wide swings in temp from say 32 f to 70 f a lot in late winter/spring).

Experienced folks, please validate and comment. Your support is appreciated.

Beast

 

Eric,

Some comments:

Re: Observation 1 - Yeah I don't know why people think singles have to be laggy... I don't lose more than 6 inches to a Z06 vette from a roll, then I destroy him. That's not much lag if you ask me I've also raced stock twin (non-seq) cars and they can't get any down low jump on me either. GO T04S! Underhood temps ARE down, you're not imagining it. The car also cools off faster. I want to add a vented hood to my setup to really top it off just like you.

Re: Observation 2 - I never tuned my car or even HAD my car with PFC + stock twins. I did the whole upgrade at once hehe so I don't know how the car ran with stockers and PFC so I can't comment.

Re: Observation 3 - The AFR changes you are seeing is probably because of just what you said... at the same boost, you're flowing more/cooler/better air so you need more fuel. A good trick for tuning is that if you find you need +5% more fuel at say 4 PSI... just go ahead and add at least +5% all the way up to P20 in that area... most likely you will need the gas! Always better to be pig rich and get a little misfiring from that at around 10.0:1 than to be lean at 12.0:1 and blow something on a tuning run. On the injectors... if you run 550/1300 with ~40 PSI rail pressure at 0 manifold pressure, my prediction is that you'll run out of gas around 13 PSI.

Re: Observation 4 - Your changing AFRs are most likely the Intake Air as you suspect IMO. Your most important area (at least here in washington DC where I live) is +50, +30, and +10. Yeah it's true that you might see a -10 when you first start up... but you shouldn't be boosting here because unless you live in Alaska or like to drive your car in snow, I bet that once it's _properly_ warmed up it would be really hard to see it stay that low.

What I did... is I took the theoretical density of air at each temp and made a graph... then I compared the stock Mazda line vs the XS-Engineering line they gave me and also "made one up" on my own. Anyhow, here's what I run right now and it is pretty good for me... This is the one I did myself and it seems to be "pretty good" from 20-60 C intake temps where I drive my car 99% of the time. Use and enjoy(?) at your own risk

+80 0.957
+50 1.016
+30 1.059
+10 1.109
-10 1.184
-30 1.250

Brian

 

Thanks for the input, Brian. After careful tuning (and my timing is about 6 deg. less advanced than yours along the boost curve) I felt good enough to go give her a good workout. Here's what I found out:

- Lag? Hell, I'm getting into boost FASTER than my twins, with boost starting at 2K rmp and full boost by 4K rpm. SWEET (in the voice of the guy from the Dodge Hemi commercials).

- Setting my boost controller to minimum setting, I can hold boost with just a touch of creep to 13.5 lbs (the wastegate's got a 12 lb spring). At that boost, the max inj. cycle I'm seeing is 72% with a fat 10.5 afr, but I was only at 7K rpm. However, that was pulling up a hill that my Sable wagon has to kick down two gears to maintain speed, and this car was PULLIN' ..... so, I think using the 85% max headroom rule, I'm going to be able to go to ~14 or 15 lbs. These actually flow 1350 per the specs I got back after they got cleaned by RC 4K miles ago. I know it's fast because the CHP officer that I blew past on the side of the road was happy to tell me that 'your pipes were singing and it took me almost two miles to catch you'.....he wrote me for 75, he said radar lost me at 82 (I'm buying a Valentine One tonight) but my log file says I hit 193 kph (~120 mph). That's amazing because that hill is steep! Needless to say, my street tuning days are over. I'm going to go to the Wednesday fun drags next week and the Test n Tune on Saturdays to get some good runs - it's just not worth the cost.

I've already started adjusting my air temp corr. factors and my numbers are moving towards yours. Once I get my egt wired up then I can start approaching your timing numbers. As I said, I'm running roughly 6 degs less timing than you.

Thanks again for your feedback, and good luck with your setup - keep us all informed if your numbers get better.

Beast

 

I'm still in the process of tuning my t04e setup and the car has been running very rich since this summer (low 10 AFRs at WOT, 15 psi). For the air temp correction, I'm currently set at:

.957
.984
1.012
1.098
1.102
1.148

The only setting I've changed from the stock setup is the 10C number (1.055 -> 1.098). This curve isn't working correctly for my car. At 20C air temps, the car is running about a full AFR richer than it was with 40-50C temps. While I don't mind being on the safe side in cold weather, my wideband is registering 9.5 or less at WOT, and I've had an occasional misfire, even with new plugs.

I'm going back to the stock setting of 1.055 for now. Because the PFC has to interpolate numbers for temps like 20C, I wonder whether the key to a good temp curve is simply to keep a fairly constant slope. The slope of my curve changes quite a bit from 30->10 and again from 10->-10, while Brian's looks relatively constant. I know there are a lot of variables involved in keeping constant AFRs over a wide range of temps, but I believe air density as a function of temp is a linear formula.

 

Since my last post my numbers now look like:

80c = .957
50c = .996
30c = 1.023
10c = 1.086
-10c=1.113
-30c = 1.148

vs.

80c = .957
50c = .984
30c = 1.012
10c = 1.055
-10c=1.102
-30c = 1.148

These numbers are closer to Wargasm's, but still less. I think for my motor and injectors the numbers are good from 30c up, but I'm still a bit low at 10c based on numbers I'm seeing right now (I held 6c aits from home to work today). I do have this odd transient lean condition once my motor gets up to 80c water temp (not air). After about 10 minutes is goes back to normal, but everything reads 2 or 3 afr points leaner for that time. I've got to go through my logs .... maybe fuel temp related? My fuel correction settings show no correction for 20 and 40, and 1.02 for 60. That's the only thing I can think of .... maybe the temp of the fuel takes longer to come up than the rest of the motor's fuids.

Anyone else out there noticed that once the motor gets warm they stay lean for ~10 minutes when it's cold out, then things normalize?

Beast