1997 B4V 1Z Grocery Getter Build

kooyajerms said:

Hey Travis, the GTG is outside of LA, you can miss all the traffic =) And it's this coming Saturday hehe.

The lag is obvious, but I also can see if I were to close the vanes more to 3-4psi at idle, my pressure differential would be pretty high but it would be responding more like Hatemi's or yours. I'm sorry I keep beating this dead horse, but I had enough problems with the jeep turbo, I don't wanna over run this one.

I actually did that exact thing where I video'd emp gauge and named off what the boost was hitting. Only problem, the camera washed out the white gauge and it was all a loss.

I'm going to move the emp gauge right next to the boost gauge to show y'all. I did a video of the emp, while I did some wot in 1st to 3rd. That was before I closed the vanes and shortened the rod to where it is now. http://www.youtube.com/watch?v=4U-7FLePWp4

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Your gauge does not look like it's glycerin filled and the needle movement appears very damped (and the pressure is actually very "not damped"). I'm guessing that your gauge has a very small damping orifice in it that may be slowing the gauge down. It appears slow to respond but without a boost gauge to compare it to it might be hard to tell.

For a quick test - when running at ~3000 RPM moderate load (3rd gear flat to slightly uphill), the EMP gauge should look like it's almost directly connected to your accelerator pedal with very little lag - push on the pedal 50% and the EMP's should rise almost immediately for the spool up spike and then fall back down to ~1:1 with boost.

Here's my 'Dash Daq' video I took a couple years ago with RC6 for comparison.

For troubleshooting purposes, it might be worth it to go to your local Fastenal/Grainger like place and get a couple 40-60 psi glycering filled gauges and put them side by side so you can monitor EMP's and IMP's side by side. They're relatively cheap ($20 or so each). I found that a small vacuum gauge is also helpful to see what the VNT is doing. Once you get used to it you can really get a feel for what is going on with these 3 gauges - kind of like a live VCDS log.

Center Back Mount from Fastenal for ~$23
1-1/2" Dia Vacuum Gauge ~$10 (not filled as the N75 is very smooth and fast)

Man I wish my boost was controlled like yours FUB

dieselpower04 said:

Man I wish my boost was controlled like yours FUB

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How is yours different? Mine looks like his, although my EGTs are lower. I think I'm running less fuel, however.

Looks like I'm gonna miss the dyno this saturday. Can't get everything dialed in on time.

Here's hoping for a miracle.

IndigoBlueWagon said:

How is yours different? Mine looks like his, although my EGTs are lower. I think I'm running less fuel, however.

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Mine is touch the throttle too much, go from 2 psi to 15 psi

Sick car

Mine isn't that controlled either Dieselpower haha. I ordered the gauges they should be here tomorrow, I'll install them this weekend and take a quick video of it all.

kooyajerms said:

Looks like I'm gonna miss the dyno this saturday. Can't get everything dialed in on time.

Here's hoping for a miracle.

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Faliure is not an option! Your miracle in a box left toledo on a plane at 8:44pm

hahaha you're miracle in a box, that's great!

My EMP gauge is isntalled. Hopefully I can get a video of the gauges when running it. I found some pretty interesting stuff in regards to my boost and EMP heh. Trying to find a working digital camera now. If I don't get it tonight it will be up by tomorrow! Mainly cause I can't leave this line running up the hood and through the window

Keebler145 said:

hahaha you're miracle in a box, that's great!

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In spectacular fashion, the USPS failed to deliver my boxed miracle despite being guaranteed to be there by 3pm today. And now they can't even tell me where the package is......

As a consolation the Socal GTG was very fun, great turn out, everyone got dynos, tunes, and a clutch job was done. My guests were happy, makes me happy.

I need a beer, or five.

kooyajerms said:

As a consolation the Socal GTG was very fun, great turn out, everyone got dynos, tunes, and a clutch job was done. My guests were happy, makes me happy.

I need a beer, or five.

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That sucks dude =/

http://youtu.be/O__Dx3DR1nw

http://youtu.be/zm1rCFCvInM


Those two videos are my pulls the videos aren't too great I'll try to get more later. The first one is a 2nd gear to 3rd gear WOT pull. My tune is for 28 psi but I think I had some heat soak going on from driving around town and I had the A/C on. The second video is a 4th gear pull from 1900 rpms WOT and actually hits a full 28psi. It surges in the video from about 2000 to 2400 rpms lightly I did it only for video purposes I never drive the car to make it surge any other time.

My EMPs closely follow my boost once the throttle is on and I'm running the car out. Initial spool up only has a momentary spike. I just wished I could get the surge sorted out so I don't have to worry about the car when other people drive it.

What's up with that 4th gear pull? Boost seems to slowly rise up to 28psi yea?

Mine jumps a lot more aggressively than that, I'll do it this week.

In comparison to yours yeah it does, you can definitely tell it's laggy. Duty cycle is asking for the boost, the turbo is just real laggy.

Cars back up and running. Fuel Pump may be working way too well... Thing is smoking a lot more. Torque steer is on.

Here's a 6k log run I did. IC heatsoaked because I started at 116*F. Woops. What's the bump that shows up at the end of all the logs I've been doing recently?


I'll take some daytime logs of the gauges soon.

I often see references of EMP:IMP ratios, do they apply across the spectrum?

For example, I hear 2:1 ratio as the max safe ratio(just pulling simple numbers here).

So I want to run 20psi IMP, this means I can hit 40psi EMP.
While the turbo is spooling, at a given moment I am at 10psi IMP, is my EMP limited to 20psi to remain safe or would it be considered safe to allow it to hit 40psi?

Thanks,
Jon

I'm not sure I even understand how the turbo works enough to answer your question so here is just my two cents...

I believe there is a point where too much back pressure is dangerous but when they say ideally you want 2:1 on spool up and then 1:1 on sustained boost, that is the most efficient range for the turbo...

@jeremy - your turbo seems to be slow to spool also if I'm looking at the chart correctly.. 12 pounds of boost at 2400 rpms? I'll try to take some logs tonight and compare them to yours. My car is finicky though and sometimes I meet full boost and sometimes my EMP's go 1:1 like my first video posted and it doesn't go much past 22 or 24 psi.... of course I didn't have the laptop hooked up at the time so I'm not sure, it very well could have been exactly the requested boost.

Keebler145 said:

That sucks dude =/

http://youtu.be/O__Dx3DR1nw

http://youtu.be/zm1rCFCvInM


Those two videos are my pulls the videos aren't too great I'll try to get more later. The first one is a 2nd gear to 3rd gear WOT pull. My tune is for 28 psi but I think I had some heat soak going on from driving around town and I had the A/C on. The second video is a 4th gear pull from 1900 rpms WOT and actually hits a full 28psi. It surges in the video from about 2000 to 2400 rpms lightly I did it only for video purposes I never drive the car to make it surge any other time.

My EMPs closely follow my boost once the throttle is on and I'm running the car out. Initial spool up only has a momentary spike. I just wished I could get the surge sorted out so I don't have to worry about the car when other people drive it.

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During the 2nd/3rd gear pulls the pressures are quick to respond, like I'd expect. The exhaust is 1.1-1.2 times the intake pressure after it's spooled up which is "pretty good" in my uneducated opinion. Spool up spike also looks "normal".

The 4th gear pull looks totally different - very slow to spool, very high EMP's that don't drop from the initial spike. It's like the vanes close and don't re-open from the initial spool up to let the turbo breathe. I didn't see any surge on the boost gauge - do you hear it?

JFettig said:

I often see references of EMP:IMP ratios, do they apply across the spectrum?

For example, I hear 2:1 ratio as the max safe ratio(just pulling simple numbers here).

So I want to run 20psi IMP, this means I can hit 40psi EMP.
While the turbo is spooling, at a given moment I am at 10psi IMP, is my EMP limited to 20psi to remain safe or would it be considered safe to allow it to hit 40psi?

Thanks,
Jon

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I'm no turbo expert, but here's my take on it...

Ideally, you'd have the least EMP for any given IMP as any EMP is extra work that the engine has to do. Since EMP's are a necessary evil to get the benefits of higher IMP's (and associated mass airflow), the goal is to have them as low as possible.

It seems that most turbos run between 0.5-2.0 EMP's to IMP's once spooled up. The intial EMP spike is just to get it spooled up and is not as important for overall performance.

My 17/22 runs 1.0-1.2 EMP:IMP ratio at steady state conditions with a spike up to ~40 psi on WOT spool up from low RPM's. Lower RPM's and higher load's give the lowest EMP's compared to higher RPM's and higher loads.

It looks like Keebler's turbo runs similar EMP:IMP on his 2nd & 3rd gear pulls, but the big thing missing from this data is mass air flow. I'd be willing to bet that a 15, 17/22, GT2256, GTB2260 all running the same EMP:IMP ratio's will have vastly different mass airflow due to compressor efficiency.

I think EMP:IMP is a tuning tool to make sure things are setup correctly. I've had a tune that ran 7-10 psi boost at 60 MPH with 15-20 psi EMP's steady state. Check my actuator and it hits full stroke at ~12inHg and starts moving with any vacuum applied. Adjust the actuator to move at 4-5inHg and full stroke ~20inHg and boost came down to 2-4 psi and ~10psi EMP's. Another tune with less VNT command runs ~0 boost and EMP's at 60 MPH and is just as responsive with 5 MPG's better.

Hope that helps

Kooyajerms, sorry if I've taken your thread off topic

Not at all FUB, it helps me understand my own situation. When I get some videos up, I hope you can comment on that and all is forgiven =)

I took some videos, but man it was shaking bad, and not worth posting (they are on my youtube account if you want to torture yourself).

Jeremy

Fix_Until_Broke said:

During the 2nd/3rd gear pulls the pressures are quick to respond, like I'd expect. The exhaust is 1.1-1.2 times the intake pressure after it's spooled up which is "pretty good" in my uneducated opinion. Spool up spike also looks "normal".

The 4th gear pull looks totally different - very slow to spool, very high EMP's that don't drop from the initial spike. It's like the vanes close and don't re-open from the initial spool up to let the turbo breathe. I didn't see any surge on the boost gauge - do you hear it?

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You can hear the surge ever so slightly very light and faint cha cha cha sound. Its soft enough I tried recording it at low speeds with a mic under the hood of the car and couldn't even capture it.

The turbo is very slow to spool when I go WOT or roll into it from anything below 2,200 rpms. Jeremy was having similar issues and I had just chucked it up to being such a large turbo that isn't a VK series. However, no one else seems to agree. Which makes sense considering Jeremy has a VK series turbo with a smaller turbine housing and is still suffering from (or was I'm not sure) similar symptoms minus the surge noise.

I really don't mind losing my bottom end torque seeing as it was only good for roasting the tires and not really going anywhere. What bothers me is the surge noise. I've been watching Jeremy closely as he keeps adjusting the stop screw on his turbo and I'm hesitant to even touch mine, let alone adjust it from factory placement.

With the turbo responding soo differently at different rpms it would make it difficult to find a "sweet spot" for the stop screw anyway I would think.

@Jeremy, if my trolling on your thread is too much just yell at me, I didn't really want to start another thread but, I don't want to get too far off topic either.

I think we're all on the right path in getting Jeremy figured out, I posted what I posted because of offline discussions between Jeremy and I and the responses are great.

I am waffling on my decision for a big turbo because of all this that I'm seeing. I was almost ready to grab a gtb2056vl but I have about changed my mind.

Jon

It's all for the better good, discussion is helpful for all interested parties. Remember, I'm not a mechanic, nor a tuner, so there is a possibility it's an easy fix that I just can't see.

I missed my opportunity on Saturday, so it's still just me futzing with it, and sending emails and pms to people for help.

Videos from this is this morning. Don't mind the Subbie sounding engine, that's what a loose injector causing an exhaust leak sounds like. I actually like it, other than the extreme smoke and all that.

FUB the emp gauge is a bit dampered, my fuel filters I put before it to keep soot/moisture out, have probably filled up and I will go replace them soon.

getting on the fwy
http://www.youtube.com/watch?v=sqHqEqWhkDE
streets going up hill. Don't mind the early wonky boost gauge, map wire was loose.
http://www.youtube.com/watch?v=cJOH-q6Ufus

-As you can see, during cruising emp:imp can be almost 2.5:1 and my assumption is that's a non issue being it's not "on boost"

-Why does the engine desire a good amount of emp and boost (2:1) when you start to cruise downhill on the fwy? I didn't recorded it, but it's pretty normal for it to happen.

That's interesting. My car is 1:1 at about 1psi on coasting downhill and on cruise it's still really close to 1:1 (say about 1.5 maybe 1.7:1) with light throttle downhill with 3 or 4 psi boost.

In the first video were you going WOT? The boost seems only a little bit quicker than mine, but I may have an unintentional biased opinion on it. The control looks very steady though!

I would think it has something to do with the tune but, that's all I would be able to say on that =/

kooyajerms said:

-As you can see, during cruising emp:imp can be almost 2.5:1 and my assumption is that's a non issue being it's not "on boost"

-Why does the engine desire a good amount of emp and boost (2:1) when you start to cruise downhill on the fwy? I didn't recorded it, but it's pretty normal for it to happen.

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1) I don't think that is an issue. When cruising you are using very little fuel, meaning little exhaust flow available. To extract energy to compress the air at the intake side takes work (pressure x velocity- similar to HP being a function of torque and speed). So when volume is low, it needs more pressure to do the same work (on intake side).

2) Same thing going downhill, especially with almost no fuel. Very little exhaust flow requires more pressure to make the work that creates the intake pressure. It may also add some sort of "engine braking" force, as the engine has to do work to compress the air coming in?


I think it also depends on the tuning, how they set the n75 duty cycle for those low throttle conditions.

robnitro said:

1) snip....


I think it also depends on the tuning, how they set the n75 duty cycle for those low throttle conditions.

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kinda what I was thinking but I don't know enough to comment on it really

These aren't WOT, these are to first take care of my concerns about low rpm emp during gear changes, and just stabs at the pedal.

So yeah, there's more there. I do remember Mark saying the tune is set so if I let off, it's giving it boost for the upcoming gearchange. That's assuming I'm looking to upshift real quick.

kooyajerms said:

Videos from this is this morning. Don't mind the Subbie sounding engine, that's what a loose injector causing an exhaust leak sounds like. I actually like it, other than the extreme smoke and all that.

FUB the emp gauge is a bit dampered, my fuel filters I put before it to keep soot/moisture out, have probably filled up and I will go replace them soon.

getting on the fwy
http://www.youtube.com/watch?v=sqHqEqWhkDE
streets going up hill. Don't mind the early wonky boost gauge, map wire was loose.
http://www.youtube.com/watch?v=cJOH-q6Ufus

-As you can see, during cruising emp:imp can be almost 2.5:1 and my assumption is that's a non issue being it's not "on boost"

-Why does the engine desire a good amount of emp and boost (2:1) when you start to cruise downhill on the fwy? I didn't recorded it, but it's pretty normal for it to happen.

Click to expand...

Actually, looking at both gauges and seeing how the EMP's respond to "pedaling" the throttle, I should retract my earlier statement about the slow EMP gauge.

~55 seconds on the uphill streets video shows some good steady state pressures with boost greater than exhaust and pretty quick response. I imagine tuning the larger turbo's is a bit more sensitive than the smaller ones.

Crusing and low power emp:imp ratio's are not of great concern as you said. 4 psi EMP and 2 psi IMP is not really a problem and is also in the low inaccurate range of the gauges. I like to see very low pressures (0-2 psi) during normal flat cruising at 60-70 MPH

I've seen the overrun condition before - it's tune/tuner specific. It's kind of wierd to see 4-5 psi boost/8-10 psi exhaust, lean into the throttle a little and watch both pressures go DOWN I don't know the logic behind closing the vanes all the way on low load/overrun - maybe a bit quicker response on tip in?

One thing on all this discussion about EMP's and IMP's at low/moderate loads is that it's probably very dependant on what turbo you're running to get it/keep it spooled. The EMP:IMP ratio is probably most useful for full power evaluation and transient response tuning. If you have a 40-50 psi EMP spike for 2-3 seconds when you lean into it, your tuner probably needs to pull the VNT back sooner or not as far in the first place (or you need to adjust your actuator). You might have to comprimise and have some higher EMP's in low load conditions to get decent response on a larger turbo so that you can have good performance when you get after it. This is all just a thought experiement for me as I've only driven one 2260v with a large boost leak for a few minutes with only a boost gauge so I don't have any first hand experience with anything other than the 17/22.

robnitro said:

I think it also depends on the tuning, how they set the n75 duty cycle for those low throttle conditions.

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I totally agree, ive noticed the vanes are closed partially at low throttle when surge occurs.

Fix_Until_Broke said:

One thing on all this discussion about EMP's and IMP's at low/moderate loads is that it's probably very dependant on what turbo you're running to get it/keep it spooled. The EMP:IMP ratio is probably most useful for full power evaluation and transient response tuning. If you have a 40-50 psi EMP spike for 2-3 seconds when you lean into it, your tuner probably needs to pull the VNT back sooner or not as far in the first place (or you need to adjust your actuator). You might have to comprimise and have some higher EMP's in low load conditions to get decent response on a larger turbo so that you can have good performance when you get after it. This is all just a thought experiement for me as I've only driven one 2260v with a large boost leak for a few minutes with only a boost gauge so I don't have any first hand experience with anything other than the 17/22.

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Without the closed vanes at part throttle spool would be compromised when stamping on it but i still think with tweaks to the tune this can be rectified.

With a GTB2260VK on a stock engine almost full boost can be obtained around 2300rpm without surge so the 2056 in theory should be a little quicker.

1:1 boost:emp would be ideal, a lilttle more wont hurt too bad!