Only somewhat annoying. It's a racecar right? Changing rear diff fluid is pretty easy anyways. I have the TRE max lock with all the goodies... It's too bad it doesn't meet the rules.

I run diaqueen when I'm on street duty, and I run the redline ns at the track. You can tame the ns by using a friction modifier.

 

Only somewhat is good. I feel like the HP+ are well past the point of somewhat annoying I was going to change all the major fluids to start next year so I'll put that on the list for sure.

If just rearranging the stock plates can make this big a difference I can't imagine what a "real" diff does!

 

Have you had any issues with the stock IC piping poping off? I've had issues with mine coming off at the throttle body, even with t-bolt clamps and hairspray... trying to fix that in an STU legal way.. wish they would just let us change to a hard pipe, not like its a performance part heh.

 

that happened to me a couple times but never after I swapped for one with a t-bolt clamp...

 

I've never had that problem...

 

Pulled the tube off, there is definately a different feel right around where the lip from the TB would sit, wonder if thats whats causing it to pop off. The mesh around it looks a bit frayed too.

 

So, to get this up to date:
-Boost leak test done. It's not leaking boost.
-Newly cleaned OEM IX injectors are now in the car.
-New OEM WGA is now in the car.
-New Denso front O2 sensor is now in the car (as of today).

I haven't driven the car enough to let the fuel trims totally settle after the O2 sensor. The long term low was at +3.5 after about 2 hours of driving. The short term trims were often +10 or +11 at idle, so I'm guessing it was going to creep back up eventually. The wideband was reading the same as it was before at idle, cruise, etc so I'm pretty confident the O2 sensor was not a problem, but I wanted to eliminate it as a possibility and it was cheap (like $50 on Amazon).


F*.

I'm re-reading this stuff now, for the dozenth time, and *just* realized... those are not my AFR's, those are my boost numbers. The AFR min/max's are at the bottom of the graph. And they are pretty normal.

What clued me in: my wideband (AEM UEGO) has me solidly in the 11's during a 3rd gear pull. So I was trying to figure out what changed that would have affected that... ugh. Stupid non-labeled axes with similar scales.

My long term low fuel trim (before changing the O2 sensor) is still in the +9 to +11 range. So the car is still compensating for something.

There are really two problems, which may or may not be related:
* The low fuel trim keeps ending up in the +9 to +11 range, indicating that the car is running lean and is adding fuel to compensate. This may or may not be affecting how the car behaves under WOT (most people seem to think that the low fuel trims don't matter at WOT, but not everyone).
* The car made less power than similar STU cars on the same dyno with similar mods and the same tuner.

The cliff notes:

Aprilish:
* the car dyno'd at 189 whp when it was stock, running super rich.

Juneish:
* The car made 256 whp with an STU tune and pretty much all the normal STU bolt-ons, tuned with AFR's in the 11s. Other STU IXs on this dyno have been 280, 290, 296 with very similar mods.
* The car appeared at the time to be making slightly less boost than a couple other STU cars, and perhaps more wavily, but not more than a pound or a pound and a half.
* The car was misfiring when tuned. The shop replaced the plugs with used ones. The tune was able to be completed

Julyish:
* The car starts misfiring 2 weeks after the tune. Replacing the used plugs with brand new OEM ones made the misfire stop.

October:
* The car misfires at Hershey, and throws a code.

November/December:
* Compression test is okay.
* Leakdown test showed minor combustion escaping through the spark plug holes. Despite this, leakdown was less than 10%.
* Coil packs, boots, plug wires replaced with new or like new parts.
* MAF cleaned.
* Wastegate actuator replaced with new OEM one.
* Fuel injectors replaced with cleaned OEM ones.
* Boost leak test shows no issues.
* Wideband installed, shows car still running in the 11's during 3rd gear pulls.
* New front O2 sensor installed.

The only thing that I know for a fact is wrong is the leaks around the spark plug holes. That *might* explain why the car is still adding fuel. I think that I've pretty much tried everything else.

If the spark plug leak isn't affecting WOT, then hopefully the main issue with the car not making power was a weak WGA.

edit: Hopefully #2 is that some combination of little issues (plugs, coil boots, etc) meant that the tuner had to hold back, so now that there are a bunch of fresh parts in there, the next tune can be more aggressive.

If I get it dyno'd and tuned and it comes back with pretty much the same numbers, the only thing I can think of at that point is to find a used IX head, do the compression/leakdown again to make sure it's okay, and try again, possibly with some corn.

 

It's 2012!!

It’s a new year, I got a new change of gear

I had wanted to make the 11-19 NASA event but couldn't, so when another opportunity came to run at VMP I took advantage. Maybe this will help the cobweb thing.

Event #1: NASA-X @ VMP, 1-15-2012

Setup (new stuff in bold):
Moton Clubsports
full soft, front and rear
600/800 springs
-3 / -1, 0 toe
245-40-17 Dunlop Z1s on 17x9 SSR Type C RS, 15mm spacers in the front
31/31 psi
WORKS 24mm rear swaybar on full soft
Factory rear differential rebuild
Conditions: 30s and overcast

NASA’s autocross program isn’t quite as ubiquitous as SCCA’s across the country, but it is pretty strong in the Mid-Atlantic. They’ve been running events at Virginia Motorsports Park in Petersburg for a while - using SCCA classing back in the day, and using what is basically NASA TT classing for the last few years.

NASA-X classing doesn’t work out very well for me. Busting out the slide rule:
Total +30... so I am 10 points into NX-A. The MR gets shafted as covered in past threads. Oh, and ten points for remote reservoirs, for autocross? I mean, remotes are nice, but they are not Hoosiers...

Anyway, this is an STU car so it’s not really a big deal... just running for fun.

For this event, Mike (turbowhore) was codriving since his car no longer has AC or a radio and it’s a 3 hour drive for him (maybe more). He was heat 2, I was heat 3 - we wanted to be in the same heat so we could keep the tires warm but they wouldn’t let us.

The course was very fast - Sam Strano designed it (not sure if it was tweaked after original design or not) and it featured a very, very fast section into a very slow section. Mike mentioned that there was a long straight and I thought about finally upping the rev limiter from 7600 to 7800 but after walking it I realized that would be futile and we were going to have to use 3rd. I have never had to do that at an autocross before (somehow).

Mike went first and he was having problems keeping the rear end in check. The alignment specs of -3/-1 were fine when the car was power-understeery but now that the diff is fixed I think I need more camber in the rear so it . I had this on the to-do list, but I wasn’t planning on running an event until March so I hadn’t gotten around to it yet. The tires were very cold, especially the rears which were getting almost no heat in them. Mike was told that he hit 14 cones on his first run. That has to be some sort of record. The results say +5, but I think that's conservative. Entire slaloms went missing. I think my codrivers are cursed. Something something Dark Side. Mike ended up with one clean run, a 59.7

I drove heat 3. Since Mike usually runs a BSP 350z, and since this was January, he brought his tire blankets. I felt like a douche using them on Dunlops, but it was really cold and really windy and it helped a little.

First run I spun in the same spot Mike had spun a couple of times. We were theorizing that there might have been some fluid there, because darn near everyone was going through there a bit sideways. (and there was an M5 with steam billowing out of the hood ). I was marked off course after the spin.

Second run I came flying into the straightaway and blew the braking zone and had to go around the really slow part. Another offcourse. According to the MaxQ, nothing redeeming about this run

My 3rd run I got things a little more together. I was still really tentative in the first half, and I missed the braking zone a bit at the end of the uberstraightaway but felt pretty good about the back half.


Sorry about the wind noise. This was the first time I’ve used the GoPro. I’ll probably pick up a micover or similar soon.

On my 4th run I hit two cones at the very end and it wasn’t faster - 58.0.

On my 5th run I blew the braking zone again, and DNF’d. One of the problems I had in this section was my proclivity to want to heel toe. In a normal autocross situation where I know I’m going to be in 2nd the whole time, this never happens, but in this situation (which, again, was totally new to me) my brain got hung up knowing that I was going to need to downshift so my foot was further to the right on the brake pedal than usual. As a result, when I was braking hard, I was still pushing the gas pedal down quite a bit, and the car wasn’t stopping (shocker). I did this on 3 out of 5 runs. We don’t get too many courses like this, but I’ll definitely plan better for this if I come across it again.

MaxQ stuff



It was a very preseason event so I didn’t take too much time with this - I was mostly just wondering where my worst known mistakes were. I compared runs 3 and 4, my only non-DNFs.

Zone 1/start: Pretty much a wash until the very end. In the last offset gate before the big straight, run 4 took it too wide and had to get off the gas to enter the straight. Run 3 faster here by .5.

Zone 2: As a result, run 3 peaked at 75 (!!!) mph here vs 72.2 for run 4. Run 4 did a much better job slowing down for the braking zone and the death turn of pain though. As a result, run 3 had to slow down to 17.8 mph, vs 22.8 mph for run 4. This made a big difference in the run through the back slalom. Run 4 faster here by .5.

Zone 3: Run 4 hits the rev limiter (61.2 mph) but run 3 only gets to about 57. However, run 4 doesn’t slow down enough for the slalom, enters too fast and has to back off at the end to enter zone 4. Run 3 catches up and enters zone 4 with a .5 advantage.

Zone 4: Run 4 is still recovering from getting bent out of shape entering the offset. Just in the first couple seconds of zone 4, run 4 loses .6 to run 3. The rest of the run is kind of a wash. Run 4 does hit two cones though.

So, a 56.xx should definitely have been attainable. But Mike and I were both having problems trusting the car because it was breaking away so not-progressively. The car will be re-aligned before the first DC event for sure.

edit: Results:
I had the 10th fastest raw time out of 87, and I'm 99% sure it was the top time on street tires, narrowly defeating one of those pesky God's Chariot ST Civics. I was 1st of 3 in the "A" class whatever that means

 

So, offseason task #1: figure out why the car is down on power and fix it.

After finally realizing that I was reading the graphs wrong, I reevaluated the various maintenance things that I'd done. I was pretty sure that regardless of power, the car had had a fuel/spark problem of some sort (causing the misfires) and that it was now fixed. I was pretty sure that the car was no longer running rich (at WOT at least) thanks to the wideband. I was also pretty sure that the boost was tapering way too much, and that was a big difference between my graph and RJones's. But during 3rd gear testing it seemed like that wasn't happening and the car was no longer tapering to 13 psi. So... was it fixed?

I took it back for a re-dyno and re-tune. I asked for two tunes - one for STU and one for not-STU (i.e. non SCCA events where I didn’t have to worry about classing). I had a decent idea that I wouldn’t get a lot of power out of this, since I didn’t want to change the boost pill, or add a boost controller, just to have to remove it before SCCA events, but I wanted to see how much was there.

After hanging out in the lounge, posting some snarky stuff on EvoM and going through my RSS feeds, Chad came back with some dyno graphs. He started off with,

“We were only able to get about 5 hp over the baseline...”

And I was really worried. After all this, only 5 whp? I was going to have to be down 30+ whp to the other cars in the class? Crap. I’m going to have do something with race gas, or something...

After talking a little more, Chad pulled out the dyno graphs and I noticed that there was a lot of gap between the low lines and the high lines. And then I realized that he had only gained a little bit of power on the not-STU tune vs the STU tune - but the car had put down 290 whp on the new STU tune!



Solid line: ASP tune. Little dots: STU tune. Big dots: old STU tune.

Only 267 wtq though. I am guessing that my tubular manifold is part of that.

I'm guessing Chad doesn't see a lot of Evo owners this excited about getting 290 whp

The baseline today (when I came in) was 280 whp so the re-tune only gained about 10 whp over the old STU tune, and the car got 24 whp just from fixing stuff. My best theory on this is that the WGA was shot. It was a car from a very cold climate, maybe that fatigues the spring faster, or something? But it was probably a small contribution from a number of things (clean injectors, fresh ignition bits, etc). Plus it's January instead of June.

As for the “boost tables changed” tune, it only gained a little bit of torque in the midrange, but not worth writing home about. Apparently without changing the boost pill or something similar, the stock solenoid is doing pretty much all it can at stock boost levels and can’t really pick up much power. That looks consistent with what Doug found in this thread - a lot of power if you remove the pill. I thought about it but I didn’t want to have to remember something like that between events. He put the STU tune back on the car, correctly figuring I wouldn't bother too much with the ASP tune since it wasn't a big gainer.

There’s no doubt more testing and tweaking to be done here, but for now, it’s in the ballpark. I can re-visit this when I have the handling figured out

 

Nice! Congrats on getting it figured out. That's a nice bump in torque all the way.

 

I still can't get over how badly I drove your car on Sunday. Uber fail. Back to my silly datsun with cheater tires before my ego is too badly bruised.

Also, I would definitely give taking off the rear sway a shot.

 

remind me again what kind of dyno your results are from? On the dynojet we did ours at, iirc, removing the pill added about 15% more boost, with the gains pretty even across the graph.

and yeah, taking the pill in and out turned out to not be very feasible, I had it out after the tune and for a track day, but once the season started it went back in and I haven't bothered with it since.. a waste of time/effort really...

 

CBRD's Mustang dyno, aka heartbreaker.

 

I posted on another thread, I added rivets to my 3-3.5" t-bolt clamp to give it some bite. I also bought 2.75-3.25" clamps so the clamp doesn't max out when you tighten it. I havent used them tho because my rivetted one works.

 

Thanks for the update. I'm learning a lot from people way ahead of me sorting issues out