curly

iTrader: (25)

Also, holy fast course batman. You're no longer N/A, get that bitch in 3rd. Jesus.

navalhawkeye

Dyno plot looks very unimpressive in normal view.




Here's the tune, and a log from a run on Saturday.

Log: https://drive.google.com/open?id=1e1...T-zCifyHot1fVq
Tune: https://drive.google.com/open?id=13Y...LEjSDlagYJzbKb

Hoping the spool issues are related to it just running on wastegate pressure?

Video from yesterday:
Some brain dump random thoughts:
- Definitely need to get boost controller working for next event. I think that's why the spool is pretty terrible
- Check toe
- It understeers pretty badly, imo. Especially at high speed. Go up in rear spring rate?
- Someone said to move the upper wing element rearward. It's too far forward from trailing edge of lower element. He works in aerospace, so I tend to believe him.
- See understeer related to higher speed, and wing change...more rear downforce would also result in more understeer at higher speeds
- Fix splitter dragging. That's probably not helping the understeer, either
- ******* turbo to downpipe exhaust leak is annoying
- Probably should change left front wheel bearing...

Car pic

Leafy

iTrader: (1)

How have you gone through so many more wheel bearings than me? Do you not regrease them with dominator and torque to breaker + pipe ftlbs?

navalhawkeye

What do you mean? This is the second one in 5 years. I can't remember if this is the one I already changed, or if this was the Duralast piece of junk.

Leafy

iTrader: (1)

I swear I remember you borrowing one of my spares once and also wanting to borrow one another time and defusing not to.

flier129

iTrader: (7)

Car looks like a blast!

navalhawkeye

I borrowed one from the Davis' for Devens Tour 2015...though now that I think about it, that wasn't even a wheel bearing. The upper control arm bolt was loose.

So really, this is the first wheel bearing I've replaced out of need.

Thanks! It definitely is.

navalhawkeye

Alright...I need some help. I can't figure out why this thing isn't making any real boost until 4500+ rpm. As mentioned, the first event/dyno tune was done on waste gate pressure only. I tried getting the boost controller working on Monday, and it seemed to kind of work, but wasn't making it spool any faster.

Here's two log files, and the tune:

First log, boost controller duty cycle all at 0 at full throttle:
https://drive.google.com/open?id=1Ah...jbEPO_nwpcTJgm

Second log, boost controller duty cycle all at 25% at full throttle:
https://drive.google.com/open?id=1xY...BdJOKxUL_4g_7l

Tune:
https://drive.google.com/open?id=13Y...LEjSDlagYJzbKb (this has boost control disabled, as it was run on the dyno. I don't have access to my laptop to get the tune with it enabled atm, but...enabled, 39hz (in the range of frequencies according to DIY autotunes product page for it), closed loop)

navalhawkeye

Finally got to work on this again. Had a lot more success at getting the spool much better. Added more preload on the wastegate, which pretty much fixed everything. The boost controller seems to be working correctly. It's definitely faster from 3000rpm to 6000rpm. I was using the default rpm scale on the boost duty table....which is not ideal for what I run it at. But didn't change it while I was playing with it. Just rescaled it now, which should make adjusting it easier.

navalhawkeye

I also raised the car some, and got rid of the reverse rake. Previously, the car was just under 4" pinch weld height all around, slightly lower in the rear. It's now about 4 1/8" in the front, and 4 1/4" ish in the rear. Hoping that loosens it up some, and gets the splitter off the ground.

navalhawkeye

So yeah. The car rules. Raising it (and adding some rake) fixed the understeer. Reset the toe to ~1/8" out in the front, was basically ~0.

Things learned last weekend:
- It was HOT saturday - 90ish degrees. The car liked getting hot, too. Oil and water would get up to 230 after a run, but then both come pretty quickly after.
- Ordered singular hood vents
- Need to make some ducting for the radiator

Satuday (the hot one), the car ran flawlessly. Didn't skip a single beat. Was INSANELY fast. I had FTD by a little over 2 seconds, and had top pax on single run speed, but they average best two. Got beat by a tenth or so on average. Smaller club, so not as deep competition wise (SSR national champ got me on pax, though).


Sunday was cold and pretty crappy weather. Morning was fine. Had a mystery cone on my 2nd run which would have been good enough for top 10 in pax. Afternoon didn't go as well. I thought at the time the turbo had failed as it wasn't making any boost, and there weren't any obvious gaping boost leaks. It also sounded like it suddenly had a supercharger rather than a turbo. Finally had the chance to investigate last night, and it's the BOV sticking/not closing at low boost. Seems like once it makes 2-3psi it's fine, but below that it just leaks everything and whines/whistles like crazy. I took it apart and cleaned the **** out of it. Put it back together and tried it, same issue. I tried putting one of the washers in, and that didn't fix it either. Going to try adding one or two more and hope it fixes it.


On the plus side, I think I had a decent shot at raw timing Billy Davis if I had gotten any good afternoon runs. So at least I did make the car faster with all the mods, because there was no way in hell that was going to happen when we were in the same class.

navalhawkeye

So, it was the turbo.



Newest chinesium seems slightly higher quality. And of course the outlet was a different size, so had to order a new coupler. Test drive tonight, hopefully.

codrus

Looks like it swallowed something. Have you checked your throttle body screws?

--Ian

navalhawkeye

All screws accounted for on the Skunk2. I suppose I should check the plugs.

There was a lot of heat coloring on the shaft. Not sure if that's normal or not.

sixshooter

iTrader: (12)

Usually if a shaft has been hot enough to become damaged it's due to inadequate lubrication. Make sure you got plenty of lubrication for that shaft so that it doesn't become damaged or have its movement slowed down. More is not always better than less, but you got to have enough. Once it becomes damaged the fun's over until it gets repaired, which can take weeks.

navalhawkeye

So the MK Turbo stuff didn't come with a restrictor for the turbo feed. Is one needed?

Also, uh. This turbo is way more better. The previous one struggled to get above 12psi. This one went to 16psi with the same boost duty table. Had to scale it by 50% to get back to where I was.

bahurd

iTrader: (8)

navalhawkeye

Would appreciate the details if you can dig them up.

bahurd

iTrader: (8)

I used this one so I could alter the size if I needed to.

Vibrant Performance Oil Restrictor Fitting

FYI, I also put a gasket in the compressor housing because; a. It leaked @ 15psi and b. it never came with one. It solved the leak.

T3 Turbocharger Compressor Housing Gasket

navalhawkeye

Cool, thanks. Will do some more research on sizing.