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volkswagner

Freebird: SR20VE+T 510 Wagon

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12 hours ago, WAGON JON said:

 How loud is the exhaust with just a cat?

It's not exactly loud, the noise level is very tolerable. It's quieter than my L motor 521 with an exhaust leak 😅 and much quieter than my straight pipe GTIR.
If I only drove the car weekends or whatever I would be content, however driving it daily it starts to get a drone when cruising.
It's actually kinda odd, the exhaust note at cruise must match the resonant frequency of the wagon drivers compartment. As you're cruising you can hear the noise reverberate back and forth between the front and rear. I'll likely try a resonator at some point o change the frequency.
A lot of my noise right now is actually my terrible driveline angle due to the SR sitting at a different angle. I have to change that.

 

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Another week, another close call. 
This time I am on my way to work and a begin to develop a trailing cloud of oil smoke. Check gauges, everything seems good and come to the conclusion that my turbo seals have let out and I'll be looking for another one. Then at about 1/2 mile from work i come to one of my last stop lights and my oil light comes on. I pull over immediately and find a good stream of oil coming out from under the car. I had a quart in the car and decided to dump it in and see if I could get to work with oil pressure. I did that and was able to keep pressure all the way. Pulling in to the lot I left a near unbroken stream on the ground. Whoops. Starting to make our poor work parking look like an autozone parking lot with the oil spots everywhere.
Some lunch time diagnosis show the oil coming from this adapter.

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My VDO gauge sender has 1/8NPT and the oem location is 1/8BSPT. When installing I tried to do the "right" thing and buy an adapter. I figured this came loose. I went to tighten it and just as I lightly touched it the whole sender falls right off.... Turns out the vibrations with the heavy sender cracked the brass and it was barely hanging on.

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Easy-out to the rescue. Then I did what I probably should have in the first place. Rammed the NPT into the BSPT and gave it an extra crank to make sure the threads forged to the correct size. All good for the rest of the week. 

Not much else new hardware wise. Continuing down my tuning rabbit hole though. I've started trying to dial in my boost control solenoid. 
 

The stock wastegate spring yeilds the below. Full throttle gives a rather steady 7psi boost with a slight drop when VVL comes on. 
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After playing with the controller I can get results closer to below with boost coming on much quicker and hovering closer to the 10psi I would like to be at. Still have to work on the stability. Again you can see a load drop at VVL. This proves the saying "boost is just a measure of resistance" Valves open up, resistance drops and boost drops with it, and then gets brought back up by the solenoid. The most important line on this chart though is the red line. My injector duty cycle. Yep, thats right. Maxed out by about 6500 with a cooresponding, not good AFR increase.  

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Going to look in to upping the fuel pressure and maybe lowering the boost up top.

 

Another fun one. This does a good job displaying the effects of the VVL, as it comes on the required fuel goes uppity up.

VVL-kickin-in.jpg

 

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I keep seeing all you guys parked together at work when I drive by. Didn't see any oil spots lol. 

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Really nice build.  Love seeing a wagon built for performance.

 

For your oil pressure sender, I have use one of these successfully for my oil pressure gauge and warning light.  Should be stronger than the brass one.

 

https://www.amazon.com/gp/product/B078MRLJD8/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1

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1 hour ago, Duke said:

Really nice build.  Love seeing a wagon built for performance.

 

For your oil pressure sender, I have use one of these successfully for my oil pressure gauge and warning light.  Should be stronger than the brass one.

 

https://www.amazon.com/gp/product/B078MRLJD8/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1

 

That certainly looks a bit more stout! If I have any more trouble I'll likely jump to a filter sandwich plate. I would like an oil cooler eventually any way. I would also be able to run my VVL from it and use the adapters I have to relocate the solenoids and run both cams separately. Seems to be fine now though.

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Jeff and I grabbed a blown GTIR SR20. Known as a "54C" since even thoug it's an SR20 it shares almost no parts even with the FWD DE's non the less the RWD DET's. Weird Nissan didn't give them their own code. This yeilded a few good parts for my GTIR engine rebuild but more importantly its the right block pattern for us to start making transmission adapters to the VE series engines with RWD transmissions. Specifically, VET>CD001/CD009 and VET>Z32 being our priority.

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The wagon was feeling laggy for a while and the boost control scheme in megasquirt was proving much more difficult than I hear it should be. This made me suspect a hardware issue. So I looked into the wastegate and it turns out that my actuator wasn't fully closing my wastegate. Therefore, lag monster. As well there is a sticky spot in the stroke (gate is hitting something internal) This was likely causing all sorts of troubles for the boost algorithm.

Reduced the sticking as much as I could and re adjusted the acuator stroke. BAM, all the boost by 3K like it should be and easily controlled by the algorithm. 

 

Then the next day I'm half way through my commute and the car stops making any boost. VEry familiar feeling, like when I toasted my last turbo. Womp womp.
Drive home feeling bummed. But then get a nice surprise after a quick inspection. The E clip holding the actuator on fell off was all. Phew. 

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Grabbed some cheap ksport S13 coilovers to start playing with, quite trashed but the price is right. Rears were still good, fronts need damper replacement.

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Decided to install the rears since I currently have some super stiff bilstiens with like 800lb springs back there. Recall that last time I touched the rear was when I installed the 200sx lsd rear end. Which happened to be wider than the 510 axle which made my tires rub, so I reinstalled the stiff coils to jack it up for clearance. This meant that in order to install the adjustable dampers, I would also have to cut my lower blocks to "raise" the car at the same time to compensate for the extra static spring compression.

 

From the left. Bilstiens coming out, ksports going in, ksport as set up for the S13, the KYB I was most satisfied wit in the past.

I set the damper adjustment to match the KYB as a starting point.

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Shaved some height and also removed some angle to get the U-joints a bit happier.

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Gave myself an access hole in the rear to adjust. Conveniently, this portion of the frame is boxed in and closed out by the shock mount so there shouldn't even be water penetration.

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Helper #2 

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Test drive success, felt great. Realize I never reset my pan hard bar though so the axle was being pushed to far to one side. Corrected that now.

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I forgot to mentioned the main motivation for the shock swap. Last autocross I could not at all keep my tires on the ground. Kept lifting up the inner and one wheel peeling on every corner.
I attributed this to the rear shocks extension that maxes out and prevents droop. 
The Bilstein setup would only allow 0.75" droop! New setup puts it closer to 2.5", we'll see if this has the affect I hope for!

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With the wagon finally reliably doing daily driver duty, it was time to put the pulsar in garage.

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My AFR readings have been even more odd seeming than usual, exspecially at idle and cruise. So I took out my O2 to do a "free air" calibration and see if that helped the readings look more reasonable. Thats when I noticed this large dent in the sensor housing... oh yeah, I sent 100K rpm turbo shrapnel past that sensor 😬

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Needless to say failed calibration.

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While waiting for new O2 to arrive, I went looking else where for cause of my full duty injectors problem. Jeff suggested using the bluetooth borescope we have to record my fuel pressure gauge while driving.  The idle pressure is set at 4bar ~60psi) which should climb to about 70psi with boost. Sure enough, the pressure would plummet to 30psi after about 4k rpm. Hence my injectors would stay open twice as lon to try and get the right fuel supply. Swappe pumps out and after adjusting the tables my max duty dropped to about 50% Much better!

 

I had to investigate further.

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Turns out Walbro's have an unservicable, uninspectable  integrated filter. This probably clogged real quick before i new I had dirty tank problems and installed a pre-filter. I would have assumed the junk would have pumped on through and damaged the gear teeth and causing lack of pressure. I didn't anticipate it clogging up and causing lack of flow.

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New O2 arrived. Didnt really solve any problems but certainly is giving me more reasonable numbers and is giving me confidence in my tune.

59642984474-FC0-E1-B24-340-F-467-D-B892-

 

A big remaining issue is a persistent ignition miss. I am thinking it is megasquirt build related at this point. I've changed plugs a few times chasing this and it's nice to see they are always an even color across ports which gives me confidence my intake isn't leaning a single cylinder.

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It misses pretty consistently every few seconds at idle and cruise. May be that it does it all the time but isn’t noticeable at higher rev.s. 
 

I have a Taarks cam angle sensor , Hall effect. The odd thing is I have never once had a single trigger error from megasquirt and all my tooth logs look great. This makes me think the Trigger signal is good and it’s the actual ignition output that is having the issue.

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On 10/20/2019 at 11:03 AM, volkswagner said:

Installed an auto-adjust S-chassis clutch slave. Much better engagement now.

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What is this self adjusting slave cylinder? From what or part number? I have a '72 510 wagon that I am converting to VG33. I may need a clutch slave cylinder. Somewhere else on ratsun I thought it was mentioned about a self adjusting master cylinder being needed for the 5-speed conversion and VG. If this adjusting slave will work, it would be lots easier to do.

 

Any help is appreciated, love your wagon and hope to see you in Monroe one of these days with mine.

 

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I don't remember exactly what I got it from. I went to the parts store with my old one and checked a few cars until I found one in stock.
There was a switch over period where they all went to the auto-adjust version. Almost all of the bolt patterns and bores are the same on the cars. I wanna say I got mine for an S-chassis.

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Sorry to be such a newbie, but what is an S-chassis car?

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2 minutes ago, rosso said:

Sorry to be such a newbie, but what is an S-chassis car?

 

S13,14,15 in other words 240sx,180sx. Oh also S30, 240z,260z,280z. S130 280zx maybe there are others. In reference to this thread.. probably s13-15

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Rosso, try looking at the slave cylinder for a 1990 Nissan 240sx.  If you aren't in the US, then it could also be a 180sx or a 200sx.  Same year though.

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Yeah what they said. As a follow up, I haven't had any clutch engagement issues since I installed the auto-adjust one. Smooth and predictable every time. Much nicer to drive with.

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Not much new here. Wagon was out of commission for a couple weeks due to the starter issue returning. 
Current theory is that occasional back fires on cranking are reverse loading the bendix and damaging the one way bearing.
Can't seem to figure out why i get the occasional backfire. My starting timing is 10 degrees retarded and timed right. 

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I just put in a brand new one. We'll see how it holds up. 

Other than that, daily driving the turbo goon has been a pure joy.

 

I was able to get my fueling dialed in quickly after the new fuel pump. So it was on to more fun fine tuning stuff.

The car really seemed to stumble as the VVL switched on so I started by trying to get this better.

 

First was to change my fueling maps to dual table switching. So far I had been on a single table, and this meant that when VVL switched, the ECU was still using surrounding table data from the low cams. This would cause a sudden dip in power before the cams came back on. 
With dual table, the ECU is able to immediately switch to a separate fueling table.
With this method I was able to set the VVL and table switch to not switch on at all and tune purely low lobe.
Then I could set the switch point WAY lower than needed and tune the other table for purely high lobe.

Finally, using the VE as an approximation for power. It was as easy as cross referencing the two table to see at what RPM the low lobe power would drop lower than the high lobe power. I decided this looked to be at about 5800 rpm. 
tables.png

Notice that the rpms cales are different. The low lobe starts to drop off after 5600rpm which makes perfect sense due to tribal knowledge of peak SR20 torque being at 5600rpm. Keep in mind that with no VVL, thats what you get and it just keeps going down. 
But switching to the high cams they just start coming on to full power at 5600, and away you go!

This made the car much more smooth to drive. VVL would switch and there would be no stumble. BUT, there was still a noticeable transition. Almost like it would flat line for a while. The way I understand it is that if the system is tuned correctly the VVL transition should be imperceptible from a power stand point. if it drops power it was switched too early, if it has a sudden "kick" it was switched too late.

Looking at the data, the problem was obvious. The VVL not only changes the lift of the cam but it also increases duration which causes increased valve overlap.
This is great for an NA engine that can use that overlap to exhaust scavenge at the higher RPM. But on a boosted car, the sooner the exhaust valve closes, the sooner boost can be built up. to solve this the boost solenoid would need to slam the wastegate closed at the VVL transition to keep the same boost level.
I spent a bunch of time trying to get the closed loop boost control to give me stable numbers and struggled. The issue was that in order to get the closed loop gains to respond quickly to the VVL, it would need to be very responsive which made it TOO responsive on the initial low RPM boost build up and it would overshoot.

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This is the best closed loop control I could get. You can see the boost duty on the solenoid going all over to try and maintain the target level.
I even cheated the target boost levels on either side of the transition to get a bit of boost creep before the VVL drop. Meh.

 

 

Eventually I ditched the closed loop and switched to open loop, I was able to quickly get a more preferred response. 
You can't even see the boost transition. I still have a little overshoot to tune out.  

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You can't see it on these traces but the open loop has the added benefit of being able to keep the wastgate slammed shut at first to decrease boost lag. and also keep it wide open during low TPS cruising to prevent boost surges while in traffic and such.

 

The solenoid duty table, really shows the response needed at VVL to maintain the boost level.

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Satisfied with this scheme now.

 

 

 

I also made up an adapter bracket to bolt to the dome light holes and proved a 1/4-20 stud for standard camera mounting. 
AutoX tomorrow. Hopefully will get some fun footage from that.

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Edited by volkswagner
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Uploaded some video from the last AutoX day. The mount was too shaky and the audio got reduced when it was uploaded, too frustrated to fix at this point.
I'm mostly trying to figure out a good setup for the endurance car, it would be real nice to get good footage out from there.  
Anyone have a favorite free or nearly free video editing software that is beginner friendly? I know, probably a tall order.
 

 

 

 

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If on Windows you can use the photos app. It’s the replacement for Windows movie maker. Free and pretty straightforward.  If Mac, I dunno. I know there is a basic equivalent though.

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16 hours ago, volkswagner said:

Ya, photos app is what I made this with. Movie maker was much better. Now it doesn’t even have clip transitions, lame. 


bummer!! I liked movie maker too.

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What angle would you say the rear diff should be at when lowering about 2 inches? I know they sell wedges for that at Summit Racing but not sure what angle I should look for I have the 2 inch blocks for the rear.

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