I don't know entirely what to expect, but the baseline dyno was 189 whp rather than 215-220 like a normal IX. I've gained about as much from mods+tune as most folks but I don't think I have overcome whatever was causing that initial deficit.

One strange thing - when the car was tuned, the plugs were replaced because the car was misfiring on the dyno. But used plugs were put in. A couple weeks later the car was misfiring on the street. I would think that unless the car was misfiring on the dyno with the used plugs, that they shouldn't have been a factor, but I don't know. I've since put fresh OEM ones in and all the misfiring is gone. (previous owner had a VTA BOV, guessing the resulting richness fouled the plugs?)

Another strange thing - if you look at my dyno, there are 3 lines: baseline (lowest), mods before tuning (middle), and mods after tuning (top). With intake / header / O2 housing / turboback, the car gained nothing below 3500 RPM:



Is that normal? I would think some of those things would have helped spool.

One other thing I'm contemplating for next year is a more creep-ish O2 housing.

Should be getting the car compression/leakdown tested in the next week or so.

 

How did the old plugs look when you pulled them? Were they all similar?

 

Like this:



That's a cell phone camera so it kind of sucks, but the leftmost one looked a little darker than the others and there were some dark spots on the ground electrode (the L shaped piece, wikipedia says that's what it's called). Looking at the NGK guide:

http://www.ngksparkplugs.com/tech_su...qs/faqread.asp

There may be some fouling going on. All I know for sure is that they were misfiring shortly after the tune and that replacing them made the misfire go away.

If they weren't misfiring on the dyno I dunno if they would have affected things, but they did start misfiring shortly after... shrug.

 

Yeah, far left looks a little rich. Are those in order of the cylinders? I'm wondering if you have a weak coil pack, and when the plugs get a little fouled you start missfiring. Got anyone close by you can swap a coil pack with and try it out?

 

I had them in order at one point, but knocked them off the shelf and now have no idea. I should have Sharpied them. If I'm not misfiring anymore, how would I figure out which coil pack was having issues? Put the old plugs back in?

 

Yup. Give it a try.

 

With the 350z's...there is usually a blister on the coil pack if it has blown. I've had two go on me this year, both blistered the plastic. Just found a cracked plug on Monday...probably why the car has been so down on power this year. Feels strong again. Are you planning on being in Waldorf on the 1st with NCC?

 

No plans to.. thinking AI on the 9th and Doublehersheycross later in the month.

Hoping to drop the car off at Andrewtech to get the rear diff sorted before those, but we'll see.

 

Motor stuff

I got the car compression/leakdown tested today at a local Mitsubishi shop.

The compression numbers: 150 150 152 155. In spec or a tick high... he thought it was from carbon buildup or something. OK, nothing really wrong here.

Leakdown:
cyl 1: less than 10%
cyl 3: less than 5%
cyl 2: less than 10%
cyl 4: less than 10%

Cylinders 2 and 4 there was some browning around the top of the spark plug hole where it looked like exhaust gas had been getting out. Possibly due to spark plug overtorquing, possibly me or the previous owner. I only used a little antiseize and used a torque wrench, but, shrug. I'm not a mechanic and the guy who owned the car before me DEFINITELY wasn't. He wasn't sure if that would explain being 20 whp down or not, and said there was a way to fix it without getting a new head (began with a T, is sort of like helicoil but different, forget what he said).

He also plugged an OBD2 scanner into the car and pulled the long term fuel trim number, which came out as +10.2. He spent a while explaining it to me and I think I sort of get it now. (Short version: the car is adding ~10% more fuel, in order to hit the target AFRs. Apparently more than 5% in either direction is a sign something could be up.)

I went out and datalogged a bit on the highway. Just looking at one of the logs now, only 3 minutes of activity, one partial 3rd gear pull while merging, some cruising, some idle. I looked at the fuel trims later.
Long term low is a steady 10.16.
Long term middle ranged from 0.39 to 1.56
Long term high was 0's across the board.
The short term / in use / instantaneous value was:
-10.16 during the initial idling period
-0.39 pulling out onto the main road
-10.16 waiting at the light
-0.39 starting and going again
-10.16 cruising, then waiting to get onto the on-ramp
-0.39 getting up to speed, then WOT, and then
-0 at WOT between 6500 RPM and 7500 RPM
-10.16 again when I got on the highway and started cruising

So, that's interesting. When the car was on the dyno when it was stock, I remember it was described as running really rich, and down on power. I never datalogged it back then though. I'm guessing whatever problem I was having then, I'm still having. But, it should only be doing the +10 when the throttle position is low, so that shouldn't have shown up on the dyno. I dunno.

I'm 100% new at this, first time ever really using EvoScan. I've been scouring the forums trying to figure all this stuff out, this is just day 1. But not having to tear down the motor is definitely good news

 

Minor car prep junk

My car was missing the factory undertray when I picked it up (again, thanks Cosmo Motors). In the interest of having a totally legal car with all the right parts, I picked up a stock IX undertray for $20, and then the side piece because it was missing. And then I installed it, only to find out that I needed MORE stuff because I have the SE lip:

https://www.evolutionm.net/forums/mi...63-se-lip.html

And after installing that stuff - I STILL need the bits that fasten the lip to the undertray. They’re not the usual screw-in pop things. I used zip ties for now, and if I can’t get the right bits I will just switch it out for safety wire. Gah!

I also checked the nitrogen pressure in the Motons since it’s been 5 months since the install. Chad set them to 220 psi initially. Three out of four were at 190 psi when I measured, and one was at 90, or so it measured. I am guessing that a large part of that loss was simply from me connecting the gauge, as I didn’t get it sealed right the first time. But something to keep an eye on.

One other set of ideas about the richness issue:

http://www.autotap.com/problem4_engine_hesitates.asp
http://tl.acurazine.com/forums/showp...23&postcount=7
http://www.6speedonline.com/forums/9...good-info.html
http://www.obd-codes.com/faq/fuel-trims.php

Cliff notes of potential causes: O2 sensor, injectors, air leak, MAF, fuel pressure, coils

Here’s more detail on the 256 whp dyno run



Boost a bit wavy, dunno what to compare it to though.

Event 22: AI @ Waldorf, 10-9-2011

This event was a doubleheader - two sets of results, two courses, lunch in between.

The morning course was really fun, though limiting a bit. There were a couple thread the needle type deals and one especially harsh turnaround. There was also a pretty important late apex in the middle that set up the long straight into the turnaround. STU was pretty light, only 3 cars - me, Iman from Philly region and Jerry. Despite the short times, the average speed was very high - think of it like ⅔ of a National style course.

First run was okay - 40.1, a little ways back from Iman’s 39.7. The car was rotating great in the big sweeper and other than being a little pushy in the slower bits it felt great. But I was not dropping into that middle section that set up the straight very well - too shallow, too early and waiting to get on the gas.

Second run - took a passenger, was slower in the middle section than before. I tried a different route into the finish - waiting longer to turn in to back-side the last sweeper - and it was slower, too much extra distance. No help, 40.7.

Third run - very good sweeper, very good last half, but still didn’t drop into that middle section very well. 39.6, a good improvement over run 1. Iman was at a 38.9 at this point so all I needed to do was re-run this run, and fix the middle, and I’d be in the ballpark for sure.

Fourth run - started very well, and I finally nailed the middle, which let me get on the gas a lot earlier into the straight for the turnaround. Unfortunately, I ended up carrying way more speed than on the previous runs and I blew the braking zone. 40.0.

So I was 2nd out of 3 in STU, but PAX’d 11th out of 90 in a pretty fast group and even without nailing a great run, would have been one spot out of the trophies in the Pro class. Seems like a good sign.


Afternoon runs

For the most part it was the same course in reverse. But the turnaround was even worse, more evil, more hairpin.

My first three runs, I was well off the pace. This course was shorter but my times were slower - 40.5, 39.9, 39.5. Iman, on the other hand, had a DNF, a 38.7 and a 38.3. I didn’t feel like I was being obviously slow anywhere, wierd. I rode along on Iman’s 4th run and it was really helpful. He rode along on my 4th run and I changed my driving style completely (don’t you hate when someone rides along and you end up driving completely differently?). I was on the gas too early everywhere (how many times have I written that) and doing a lot more pushing than necessary. Halfway through the run, the tires were pissed and they let it be known... I pushed through the final sweeper and waxed the outside finish cone. Despite all the stupidity and mistakes, it was my fastest raw time - 39.4+1. I guess I was just nowhere near aggressive enough on runs 1-3, and then too aggressive on 4.

Paxed 18th/87, not horrible but given the SKREE of the last run kind of expected. Iman was 4th in PAX, just a tick behind Strano - nice jorb!

What’s next?

Next week I’m dropping the car off at Andrewtech to fix the rear differential. That’s kind of exciting.

Since the leakdown/compression test went okay, I’m going to start trying to figure out the richness thing - just cleaning the MAF and maybe a bottle of fuel injector cleaner.

After that...whatever the next wave of troubleshooting is...

 

For reference, here's my boost curve from my old STU tune. It made 265/260 on GST's Mustang Dyno.

 

Thanks for posting this. I notice that at 6000 RPM, your AFR is 11:1 and mine is like 9.7:1 Not a good sign, but a very useful comparison!

 

Yeah, that's like as rich as the stock ROM. If you lean it out, you'll definitely pick up more power.

 

Rear diff

When it came to getting the rear differential sorted out... it was time to hand things over to our tame local racing shop.



Some say... he can change an Evo clutch in 13 minutes, dead.
And that his vertebrae are equipped with triple cone synchronizers.


All we know is... he’s called Andrewtech!

They’ve been kicking *** in the Subaru community for a long time and because of their vast experience with transmissions and diffs in that space they were willing to take on rebuilding the rear diff for me, to the FSM spec. They got it done in not that long and I was back on the road the next day, without having to take the diff off the car and ship it anywhere. We went with the Redline stuff recommended by TRE. I may end up trying the NS later just to see the difference.

It was absolutely killing me not being able to test it out after all the rave reviews in the “assembled incorrectly” thread but I could not fathom a scenario on a public road where I could notice the benefits and not either go to jail or risk hitting a tree, so I staved it off, waiting patiently for a fast event on a National style course.

I threw some fuel system cleaner in my tank on the way up just to see if it would impact the fuel trims.

Event #23: Susquehanna SCCA @ Hershey-Big, 10-22-2011

Setup (new stuff in bold):
Moton Clubsports
front: 3/7 compression, 3/7 rebound
rear: 3/6 compression, 3/7 rebound
600/800 springs
-3 / -1, 0 toe
245-40-17 Dunlop Z1s on 17x9 SSR Type C RS, 15mm spacers in the front
35/35 psi
WORKS 24mm rear swaybar on full stiff
Factory rear differential rebuild
Conditions: 50s and overcast

After waking up at 5:30 to get all the way to Hershey, I was greeted by a big open but not too open course with lots of huge “choose your own adventure” sweepers, where you had lots of space to work with and had to carefully pick how much of it to use. As one of the Subie guys said, it didn’t drive as open as it walked, but it was still a blast.

My first run I wasn’t sure what to expect. I started with the compression maxed in the rear as I had been running (keeping it scientific and all). After a normal launch, shift and light jog I got on the gas when I would normally get on the gas and the car got a bit bent out of shape. Definitely not the same behavior I’d seen at past events. Hrm. I went off course as a result but continued on. Later, exiting a sweeper, I got on the gas a little too much too soon and wham! I spun the car for the first time all year. What’s this? Power oversteer? I came across the finish line giggling despite my 65+off, which must have confused the onlookers quite a bit. Brian K (2010 and 2011 SMF national champ) in his newish STR S2000 was in the 58’s so I had work to do for sure. Mike S was also his usual consistent and fast self in his CRX.

My second run I resolved to stay clean and be a little smoother on the inputs. Much better - 58.7. I was on the gas earlier but more careful in the sweepers, mostly. I was still divebombing a bit and late on at least two of the major slalom entries.

Third run - more of the same, couple minor improvements but some sloppiness towards the end - 58.5. Brian was down to a 57.8, Adam a 57.9, Mike a 58.3. Gotta represent STU a little better...

Fourth run - wanted to make sure I set up better for the second half of the first slalom, and be a lot more patient in the big sweepers so that I wasn’t going all opposite lock and whatnot. I drove the course 5-6 times in my head before going to the line. The car actually misfired off the line and it took a couple seconds for the power to come on (grr). But the run felt really good otherwise. I ended up with a 57.91, .06 behind Brian and .01 ahead of Adam. Almost had fastest ST* time... oh well. I think they announced me as 5th in PAX but said we were all in a very tight grouping. I did win STU.

Strano ended up getting down to a 53.7 (!!!) in his SS C6 Z06. To match that in my STU car I would need a 54.9. Uh yeah. I think there’s still a good chunk of time in the car - old tires, getting used to the new setup, a little down on power... but three seconds? Yipes!

When I got back to my car and started it, I had a CEL waiting for me on the dash. I fought my way to the local Advance Auto and they pulled the code - cyl #2 misfire. Figured as much. Wonder if the injector cleaner helped this one along? Even during the misfires before I never actually got a CEL.

No video, forgot the little USB camera, and only two runs were MaxQ’d before the MaxQ ran out of juice (I only charged it for a little bit beforehand). I hope to have some better video for the AI event tomorrow, er, today. Results aren’t up yet either... hoping to have eked into the top 10 in PAX but unlikely given the group 2/3 folks.



edit: 1st of 5 in STU (good for another pint glass!) but only 13th/120 PAX. Dropping down to a 57.7 instead of a 57.9 would have slid me up to 9th in PAX. Most of the people who finished ahead of me have hardware from Nationals, though.

Setup changes

In honor of this newfound lockup from the rear diff, I backed the WORKS rear bar from stiff to soft once I got home, and will be running the rear shocks at 3/6 compression instead of 6/6 for a while while I get used to it. It’ll be nice having some “make more tailhappy” available for the stickier surfaces. I may also need more camber in the rear, dunno yet. I’m hoping just the bar changes will do it.

 

very nice! do you mind if i link this post in the rear diff thread?