Rubyq60

Looks good mang

Ape Factory

iTrader: (3)

Been messing with logging via ECUtek and generally just examining data. My two biggest concerns are traction and oil temps. Now that we're hitting the 100 degree range, I though it'd be a good time to log. I'm hitting as high as 104-109 around town.

I decided to do some logs for oil temperature today as temps are approaching 100 degrees. I saw wheel slip percentage and decided to log that too as I still get quite a bit.

Here's a chart of wheel slip using ECUTek's traction control which is FAR smoother than VDC and engages sooner but in a less invasive manner. I can get VDC pretty sideways before the rear brakes get slammed on. This was acceleration in a mostly straight line. I need to do some logs with steering angle checked off too (I think that's in there somewhere). Anyway, I found it interesting as I'm definitely getting wheel slip all the way to redline despite wider and stickier Michelins.

Mind, this is only from like 4200 rpm on up. I'll do smaller logs from a dead stop as I get quite a bit of wheel spin in the first three gears. The traction control is lessening the wheel spin as I believe it's set by percentage slip. Assuming it's timing based. I'll try to do another graph overlay of timing/wheel slip.

Here's a/f ratio and wheel slip:


A/F ratio by itself:


Here's timing, Air Fuel and Wheel slip on one graph.


Did a 4th gear run, not the full rpm range. Of note, the surface was rippled and I could feel the car struggling with grip as it accelerated through the rev range. Slip is in percentage.

Traction is bottom line, air fuel ratio is top line.


I also measured oil and intake air temps. If I remember correctly, it was 93 degrees out at the time. Temps dropped pretty quickly. Oil temps, however, rose. I've been logging oil temps now that we're always in the 90's and even into the low 100's. I'm seeing over 100 degrees celsius, as high as 104 degrees. There's no oil cooling circuit in the oil filter housing like the 370Z from 2012 on up. I'm really debating putting a cooler on the car at this point.



Last one is just a closer look at the air/fuel ratio. Prior to a tune, it was almost always in the low 11's to high 9's as it approached redline. REALLY rich.

gill1606

So What would you need to do in order to increase traction of the G37 onto the road? What mods could help that horsepower and torque translate to purposeful forward motion.

Splitter

iTrader: (1)

I don't understand the traction issues you are having.

Photobocket has done you a good one, I know the pain, but what are the rear alignment specs? I had issues with too little rear toe, but that was when pushing the limits of adhesion around corners, not this crazy stuff you keep reporting in a straight line.

These cars don't have that much power, they should not spin tires in 3rd or all the way to redline in any gear. Physics doesn't work like that. I think it could be interesting to try and understand what is going on in this scenario, because it is unique.

Ape Factory

iTrader: (3)

I'm at -1.7 rear camber, toe within spec. 255/19 Michelin PSS tires. It's not as bad in a straight line currently but no where near ideal. The new suspension, wheels/tires improved things in that department. It's most definitely coming off of corners where I have most of the issues.

Realistically, to improve traction, I'd go with a 10" wheel and 285 tire along with a switch to a Wavetrac rear diff and run SPL everything out back to get rid of any slop or geometry changes introduced by rubber bushings.

Unrealistically, redesign the rear linkage entirely and run 18" wheels with a taller sidewall

Edit: I have yet to run the car on the dyno but I'm expecting a 30hp difference over the car prior to the tune. I'm guessing I'm at 365-370 at the flywheel.

Rochester

iTrader: (9)

He probably means he can shift into 3rd when 2nd gear is still trying to get traction. I mean, if he's spinning and he wants to shift, I suppose he shifts and there you have it... third gear. Not that his tires are spinning in 3rd gear. But IDK. Let's see what Apes says.

You know, since getting these short gears in the diff, if I have TC off and I'm driving hard, it's not an insignificant chore just to keep things under control in 1st and 2nd gear. And that's with 275's out back on heavy 19x10" wheels.

Maybe it's a 6MT thing. Or maybe it's me, and I suck at driving.

Splitter

iTrader: (1)

Why so much camber, and what is 'in spec'?

The camber is less of a concern, but I would get the toe checked out. I had 0 toe in on the rear and the car was undriveable. I gave up and left an autocross early because it was pointless. I now run 1/64" toe in and it's brilliant.

I'm also not sure a diff will help if your problem is not spinning inside tires. Unless it is and I missed that?

It's still not huge power for decent tires (which you have)

Ape Factory

iTrader: (3)

This is, I believe, my latest alignment. A lot of my images are out of order after yanking them from Photobucket. My plan was to go to -1.3 camber in back and -.8 in front. It rotates pretty well as is but I think I'm a hair low on the passenger rear. There's no one in town that has corner weight scales and I just haven't had the time to drive to Austin and get it done.

Splitter

iTrader: (1)

Looks good. Well, I'm out of ideas then, but I'm still not convinced something is wrong for you to be getting that much wheelspin.

Ape Factory

iTrader: (3)

I know it's weird. I should check the VLSD and make sure it's working properly. It's been like that since day one when the car was bone stock. It's gotten better with tires, dampers and alignment but it's not gone.

Here's a graph, straight line acceleration, starting at the shift from third to fourth. Surface was moderately bumpy and I could feel the rear fighting for traction. Luckily I recorded wheelslip which is listed in percentage (it's the red line).


I have another graph on my work computer that shows spin coming off a corner at near full throttle. I'll upload that one tomorrow. Reaches 30% at which point the ECUTek traction control kicks in.

Splitter

iTrader: (1)

Would be good to see a higher res photo and or the data behind this too.

Do we know how the ECU calculates wheel slip? What sensors are used to reference and wheel speed.

Ape Factory

iTrader: (3)

Here's traction loss coming off a corner, 1st gear. Loss is in percentage wheel slip as calculated off the speed sensors on the rear differential with, I'm assuming either a front wheel speed sensor or one in the transmission. The traction control (EcuTek) is active, not the VDC. I'm basically coming off the corner from idle with slip angle (wheel spin) and a bit of counter steering. I'm going to try and record some video of the dash with acceleration but I'm having a hard time finding a good mounting point for my GoPro.



Here's a larger version of the straight line acceleration graph, traction only. RPM on the bottom, traction loss in percentage on the top. This was a rippled surface, 4th gear pull. Slip tapers off towards redline. I could feel it fighting for grip and if the pavement had been smoother with less irregularities, I wouldn't have as much traction loss.


I still need to do some traction logs from a dead stop when I have time.

I also have the raw files. I'm simply plugging the data in to Excel and then graphing it. There's a way to graph data through the EcuTek program as well but I have a rather small laptop that does not make this easy.

reNeglect

Have you checkd the rear traction arms and see the condition of the bushings? They might be having to much play under hard acceleration...

I'm running - 0.8 front camber and -2 camber in the rear, traction is fairly good for the most part minus launches.

Front 19X9.5 255/35/19's (wrong sidewall size but got a hella good deal on the MPSS)
Rear 19x10.5 275/35/19's

Tein Flex Z Coilovers with SPC Front upper control arms, rear camber arms and toe bolts. Hotchkiss sways and cusco front strut bar. Ride height is around 27inches from ground to fender all around.

Ape Factory

iTrader: (3)

I haven't but given how many miles are on the car, I'd be shocked if they had deteriorated. I plan on going -.8 in the front here shortly, just need to find time to bring the car in.

Your setup is very similar to mine. We're running the same spring rate too. I have SPL rear camber arms. I may try their traction arms and see if it helps. They're not all that expensive.

gill1606

Can we please get a side view, front view of your car, like pictures. I am curious to see how your car stands/looks with the mods you have done. The stance of the car if you will.