Today was the first warm day we have had in a while. I was out messing with my timing maps again and took a video of my under-throttled ALS working.


Here is the datalog from that


I had to hold the throttle open a little to get it working which means my idle air valve isn't big enough. I might try to port it if I get sufficiently bored one day. But you can see in the log when it saw me lift throttle the timing went to -25 and it dumped in a good amount of fuel.

 

OK, it was bugging me, so I pulled of the idle valve. The ports are HUGE! It was barely opening though. After some searching I found that the Idle Valve PWM calibration stopped at 44%. I extended it out to 100% and this is what I got:



It builds about 1.75psi at the compressor at 'idle' with the 50/50 dump valve cracked open a bit. You can hear the turbo sucking, then pshhhhh a little when I switch it off and it goes into cool-down mode before returning to a normal idle. That's with me touching nothing but the switch.

 

Now we need to see a launch. Go sacrifice your transmission and clutch for the good of humanity.

 

I'm pretty sure I'd lose an axle from terminal wheel hop, LOL
You may notice the gauges are now retained by lengths of coathanger. That's because the wheel hop was so bad at the dragstrip that the gauges flew out of the dash when I launched. :(

 

I can hardly maintain rectal continence after watching this vid.

 

Time to invest in some better diff mounts and try stiffening your shocks to help control rebound. Lowering tire pressure also seemed to help. Its a blast launching off the 2-step and having it hook up (well, kind of).

 

The diff mounts and all suspension bushings are PU, The TEIN HA shocks were as stiff as they get, and the tires were 205 Kumho MX's at 27#. Violent wheel hop halfway through first gear followed by retarded wheelspin, hopped again a little in 2nd, and wheels kept spinning most of the way through 2nd. Finally could put some power down in 3rd to catch and pass the 350z in the other lane. It was pretty horrific, I don't think I like drag racing. Maybe the VHT had something to do with it? After 2 tries i decided to quit before i broke something expensive. I never have that issue with my 225 Kumho 710's at an autocross.

 

Using an j&s safeguard as well I see, nice.
Are you just using one egt after the turbo or do you also have per cylinder egt's as well?

 

I don't mess with it anymore because I can't get it to work properly. And that's just not ballin' *****. (smacking lips)

 

Just one EGT probe in #4 pre-turbo. Love the J&S. John is a cool guy.

 

It's not terribly useful in this application, and I doubt I'll use it, but it does work. What were you having trouble with?

 

This was on a MS. Whenever it was enabled. The car wouldn't go to redline during normal driving without cutting out. No problems when its off.

 

I didn't know MS had it. Are you sure it wasn't just a 2-step rev limiter for launching? You won't have a skipped-injection cool down without sequential injection either.
Either way, it should only be working when the throttle position is below around ~8%, and/or the manifold pressure is somewhere below ~100kpa.

 

I used to get massive wheel hop with the RT615's, but get zero hop with the MT radials.

Looking back, the C5 used to hop violently on the MX's but never on the 710's or ET Streets.

Back in the F-body days, 555R's used to wheel hop really bad, but ET Streets and QTP's never showed a hint of wheel hop.

 

Thanks for the shout out, wimp.

What C5? FRC?

 

Yeah. The last time fuel was 4 a gallon, the women were hot, and I was making decent money.

 

puter

 

Nice job! Some day I'll set this up with my hydra.

 

What model j&s safeguard is it that you are running on the miata?

 

It's an UltraSafeguard. I think it was originally for a Honda. John reprogrammed it for me to work with my Standalone. It tells my SM4 when it sees knock instead of intervening directly. Allows me to adjust boost and fueling in addition to timing. I'm very pleased with it. Only issue is that the LED's keep going out on the gauge, and they are potted so I can't fix them.