1997 B4V 1Z Grocery Getter Build

Haha, jeremy made his friend buy a 6 speed so he did not have to pay shipping on the sensor!

I think when you are running close to the limit of a 3 bar sensor its worth fitting the 4 bar, if a boost spike exceeds what the sensor can see the N75 backs boost off so you get severe underboost in some cases.

Ya, Jeremy made me buy the 6 speed to save on shipping lol. Sorry for the confusion should have made it clear I was joking about it being for sale. But we do think it will help so he can add more boost.

I like this concept, car isn't running right... we should put more fuel and boost at it... that should fix it all haha

^^Like^^

Please forgive me if I missed it somewhere in this thread, but... Is your tune using the MAF sensor? Or have you gone to MAP based smoke limiter?

We are using a map based tune. Maf is lost in Matt's shop lol.

Hey A5 in KY, mind throwing up a channel 11 graph so we can see how your turbo is spooling? Obviously it's not a VE... but it would still be good to compare (I need it!). I'm just not understanding this turbo's lack of ability to spool up at 2k rpms.

I don't honestly think the vk turbo has that much greater ability over the old 2056v. It's a rather larger turbo, I think honestly getting 10-12 psi at 2,000 is about all you're going to get (judging from the compressor maps at least)

Keebler145 said:

I don't honestly think the vk turbo has that much greater ability over the old 2056v. It's a rather larger turbo, I think honestly getting 10-12 psi at 2,000 is about all you're going to get (judging from the compressor maps at least)

Click to expand...

If it's the exact same compressor I have in my gt2256v, I can make 15psi going up a big hill in 5th at 1700rpms with no issue. 17psi-ish around 2000rpm. And 18psi at around 2200rpm.
So you're turbine (smaller and with better vanes) should spin up to make that with ease!

Scott I still want to go for a ride in your car and see what this is like. Cause I promise you my car can make 17 psi at 1700rpm in 5th gear. But, it's going to surge and flutter like nuts.....

kooyajerms said:

We are using a map based tune. Maf is lost in Matt's shop lol.

Hey A5 in KY, mind throwing up a channel 11 graph so we can see how your turbo is spooling? Obviously it's not a VE... but it would still be good to compare (I need it!). I'm just not understanding this turbo's lack of ability to spool up at 2k rpms.

Click to expand...

Hey now, I found your maf sensor .

I'm not understanding it either as it spooled really well for me at 2k. There's a youtube video of me rolling into the throttle in 5th gear at 2k and it shoots right up to 20psi. Apparently I really need to take a vacation and come out there...

kooyajerms said:

We are using a map based tune. Maf is lost in Matt's shop lol...

Click to expand...

Good call on the MAF, this turbo can push more air than stock MAF can handle IMO. It may have just been my 200K+ mile MAF dying, but we fought tuning issues for a long time until we ditched it. Took very little time to make everything happy with MAP base tuning and 4 BAR MAP. My tune is really good now. I am going back to the dyno on the 7th, build thread will follow.

kooyajerms said:

...Hey A5 in KY, mind throwing up a channel 11 graph so we can see how your turbo is spooling? Obviously it's not a VE... but it would still be good to compare (I need it!). I'm just not understanding this turbo's lack of ability to spool up at 2k rpms.

Click to expand...

I log from 2000 up so don't know if this will help you or not. I simply never really drive hard below that. This is a pretty typical 4th gear pull on flat ground.



I get a slight puff of smoke on tip-in, a slight gray haze until the very top end when it gets slightly darker. Just about right I would say. I only used an EMP gauge to set the stop screw (per Majesty78) then took it off so no data to offer there. My N75 duty cycle is around 20-21% at 4th gear WOT 4000 RPM (% duty cycle is inverse for my ECU). My tune is for only 28 PSI. Acceleration is pretty linear.

Thanks bud I appreciate that.

Here's mine from yesterday. (yeah it overboosted, don't mind that, look at it spool)



And Matt, car can't get all accustomed to your touch, keeps giving me the cold shoulder when it leaves you!

Is that log at WOT? Curious what the N75 duty cycle is doing there, can't tell from the plot. Can you post up duty cycle data?

Definitely looks lazy to spool from that plot, unless it was your right foot. When you log to a higher RPM does boost settle down to an even requested?

Yeah don't mind the overboost.

That's WOT, and duty cycle is about 40-50%. If you saw my other logs my highest I was able to set it to was about 50-65% compared to your 80% (inverted). Despite the fact, I shortened the rod here, but it may just be that it needs more n75.

Problem is... it's already spiking to 65psi emp this time around lol. Gotta redo some things still.

You are working with a completely different animal than me.

However, I have gathered that the ECU takes over at some point and the mapping is more like a starting point. That is probably an over-simplification, but both the ECU and your tuner need a good hardware baseline to work from. I have heard the Euro tuners say over and over to set the rod length for 20% N75 duty cycle when 4K RPM WOT in 4th gear. I would think that would be the way to go and then let your tuner work out the mapping from there.

Of course, just my 2 cents.

Oh I agree, but when ever we tried 80% (inverted world) it surged/spiked too much.

Just not many VE's out there showing much for logs n videos of their GTB setup.

It was explained to me that the rod needs to be adjusted that way to give the VNT mechanism enough dynamic range to do what it is intended to do. If your duty cycle is maxing out at 40 to 50 % you are giving up 30 to 40%+ of it's available range rendering it less effective. Again this is a simplification, but it worked for me.

You have a very unique set-up. Looks to me like your tuner needs to adjust your tune to your hardware. By compensating with the rod adjustment in the way you have, he is trying to hit a moving target.

I raced motorcycles for many years and the wiser tuners always said to "only change one thing at a time." They were speaking of the process of deductive reasoning.

If you get that rod to a closer to spec length to maximize your dynamic VNT range, I bet Malone could bring it on home for you with a few logs.

That was my intent when we moved to the reset n75 (stock toledo) tune. I thought "this is the perfect time to set the actuator to 80%." So I shortened it to 2"hg start 18"hg full. And I got 40-50% lol. I'll try that again, and shorten the rod with the reset n75 tune. Just not sure how much more that EMP is gonna spike considering my gauge maxes at 50psi (pegs past it).

Checking vacuum in the morning too, haven't put a gauge on it yet, been distracted with painting my windshield channel n roof.

If your EMP are greater than 45psi you are in danger territory.
Even 45psi is excessive.

In the last couple months, 45psi was the lowest spike I could get on the setup Travis.

the 65psi is just from the recent tune, that won't be happening again.

Gonna try some things today.

O.C.TDI said:

If your EMP are greater than 45psi you are in danger territory.
Even 45psi is excessive.

Click to expand...

Isn't EMP going to be mostly controlled by N75 mapping? Wouldn't one want to adjust the actuator rod for full VNT travel (80% duty cycle discussed) so the tuner can get the vanes open enough to drop EMP fast (and) enough?

I wonder if Jeremy's focus on EMP has not been a little premature. Seems the actuator rod length has been used to try and manage EMP where the tune should be doing that?

Not saying, asking really.

Stop screw adjustments will impact EMP significantly.

JFettig said:

Stop screw adjustments will impact EMP significantly.

Click to expand...

Only the initial spike on tip-in. Turn the screw in to reduce the spike. I found a little goes a long way.

Yes. The N75 is not allowing the vanes to relax, thus high EMP. The vanes are choking it out. At the same time. If the vanes are staying closed too long than boost pressure should be high as well.

Could be due to tuning, or the spring in the actuator is not strong enough to overcome forces on the vanes.

I do fully support the questions raised by jimbote a number of posts back about the actuator design. There are alot of variables in the design that could cause tail chasing.

Kooya- I wish you would have gotten ahold of me when you were in Portland.

O.C.

O.C.TDI said:

Yes. The N75 is not allowing the vanes to relax, thus high EMP. The vanes are choking it out. At the same time. If the vanes are staying closed too long than boost pressure should be high as well.

Could be due to tuning, or the spring in the actuator is not strong enough to overcome forces on the vanes.

I do fully support the questions raised by jimbote a number of posts back about the actuator design. There are alot of variables in the design that could cause tail chasing.

Kooya- I wish you would have gotten ahold of me when you were in Portland.

O.C.

Click to expand...

The way I tuned your car in initially Jeremy was set the stop screw to about 1-2psi emp at idle to get it driveable. Then I set the actuator rod really long on purpose, and then shortened it until n75 duty and response was normal. Then, I shortened the stop screw to set the emp spike.

I agree the actuator design is a bit unusual and could be inducing variables, however, it worked perfect here. I put over 1K miles on the car with no weird behavior. My money is still on overlooking something stupid and trying to change too many things at once. I so wish I could fly out there this weekend .

Sorry Travis, I was doing my best to get the wife to cozy up to the idea of me leaving her for a couple hours on our anniversary. Nope, couldn't make it happen, sad really, I was ready to go to Oregon City! Would have saved a lot of heartache.

Checked Vacuum finally.
At the actuator vac line 17"hg
Where the vac reservoir/recirculator valve is, 30"hg

I'm going to try to plumb the vac reservoir right on the line that goes to the n75. This is all pre checkvalve I believe (checkvalve is only for the brakebooster).


I've turned the stop screw to reduce the emp down to .5-1psi at idle. Spikes are at 35psi now, smoke and lag have increased (no engine braking from too much emp like JFettig and I may have assumed). I will look into shortening the rod once again to get to 80% and better response. I am at 2"hg crack 18" full.

You have to remember, this is from a reset n75 map tune at the moment. So we are pretty much starting over again.

There needs to be a check valve before the N75 and the vac can.
The booster should use the 90* fitting on the booster as it's check valve.
The small line should tee off the booster line, then small check valve, then a tee, one side to vac ball and the other to the N75.

I still have that check valve you told me to buy for the jeep turbo. I'll put it on when I get home. I will put the vac reservoir and the n75 line together with the check valve before both.

Here are pictures

red line goes to n75, black line that is tee'd goes to the recirculating valve (fresh air flap) and the vac reservoir. See how the check valve is integrated to the fatty brake booster line?
http://pics.tdiclub.com/showphoto.php?photo=79708&title=vac-system&cat=500

full system.

That big check valve only does the booster. The vac lines tee out of it before the check valve portion.

I would cap off one of the ports on the big check valve and cut the small check valve in between the big valve and the existing tee. Or put the recirc. valve to the other port, and leave the N75 and vac ball on a dedicated circuit.

This might help. At least we might be able to start narrowing down contributing factors.

Keebler145 said:

I don't honestly think the vk turbo has that much greater ability over the old 2056v. It's a rather larger turbo, I think honestly getting 10-12 psi at 2,000 is about all you're going to get (judging from the compressor maps at least)

Click to expand...

They are more different then you think.

If that was the case how would you explain my 2260vk making 21#'s at 2100 rpm and full boost of 32-34 psi by 24-2600 rpm as shown on my dyno charts. My file has been written using the real 60mm vk compressor map.
I only experience surge when I am at 3000' + in elevation and at 2000 rpm or less and push too hard, in these situations I should have shifted down, but I have to continue figuring out the surge conditions.

All my logs and dyno's start in 4th gear at 1500 rpm's.

O.C.TDI said:

They are more different then you think.

If that was the case how would you explain my 2260vk making 21#'s at 2100 rpm and full boost of 32-34 psi by 24-2600 rpm as shown on my dyno charts. My file has been written using the real 60mm vk compressor map.
I only experience surge when I am at 3000' + in elevation and at 2000 rpm or less and push too hard, in these situations I should have shifted down, but I have to continue figuring out the surge conditions.

All my logs and dyno's start in 4th gear at 1500 rpm's.

Click to expand...

Well, even then. If you consider Scott02's with a 2256v he is making 17lbs of boost at 1700rpms and 22-24 by 2,000 IIRC. So minus the smaller inducer you're still not doing that much better than him. For the price difference (2256v can be nabbed locally for 400 bucks) to the vk's that aren't so cheap. I was just stating I didn't feel the gains outweighed th cost.

Clearly whatever you and Scott are doing is WAY better than what Jeremy and I are doing cause we aren't getting HALF the results you two are. If you lived closer I would love to come over and have you look at the car and see what I'm doing wrong. I'll try to pester scott some more and see if he would look over what I have done.

back to topic:

@Jeremy: having the emp set at 1-2 psi idle I think was a good move. although I still haven't messed with the stop screw on my turbo as it was already at 1-2psi at idle emp. I agree with the group here. It seems like the rod length is having an effect on your spikes. Just curious though have you check the spring pressure on the vaccum/dash pot? I had one fail on my old 17/22 and made the car run super goofy... It was obvious it was bad you could compress the spring with almost no effort.