WOW! This thing feels like a totally different vehicle. Though I don't think my old turbo was functioning properly, so maybe its a little unfair comparison wise. Similar to others who have done this install, full boost (11 psi in my case) can be achieved by about 2k. I will have pics posted later with all of the modifications I did to install this. Not necessarily for the faint of heart, but by far the best modification that I have done hands down. My black smoke has also mysteriously disappeared :rolleyes:

As for the control, I used the stock (Liberty) vacuum diaphragm and reworked the VCV to operate reverse of what it normally does (0" Hg at idle 15" Hg WOT) and finally a spring operated pressure controller to limit the boost. Works perfectly. Boost builds rapidly to 11 psi then stops abruptly (I can dial this value in with the tension on the spring). Cruising boost can be varied by adjusting the VCV (>0" Hg at idle). I am glad that I decided to try this method as it is so easy to adjust and works great. It also has the side benefit of a safe fail mode i.e. loss of vacuum = no boost.

I do have one question though. Can anyone describe what surging sounds like? I can distinctly hear the normal whine of a turbo spooling up, but then above 3k WOT I get a slightly lower pitch humming for lack of a better word. Since I have never heard surging first hand, I cannot tell if that is what I am hearing.

Just watched a video of surging. Definitely not that. FI, BG you guys have this sound that I am talking about? I will try to get a clip of it.

Maybe it's your exhaust vibrating?

You will have to post some pictures of your actuator set up. Sounds like you got a good system.

How did you reverse the VCV? Mounting it upside down?

As promised some pics of the install. First the adapter plate. This was made of 3/4" plate. Two 10mm bolt holes are countersunk for cap head screws, the other two are for the 8mm stud and a 10mm threaded (I screwed up so it ended up being 1/2"). Then of course the other three holes tapped 8mm. I took all the dimensions from this post (http://www.superturbodiesel.com/std/viewtopic.php?p=279#p279). (Thanks bgkast). I also added a 1/4 NPT for the thermocouple and tapped a 1/8" NPT for pressure measurements.
https://engineering.purdue.edu/people/brett.j.bell.1/300TD/VNTPics/ManifoldAdapt
https://engineering.purdue.edu/people/brett.j.bell.1/300TD/VNTPics/InstalledAdapter
Next up is the exducer adapter. This is a 1-1/4" x 1-1/2" exhaust pipe adapter with 1/4" square welded on one side (thanks again bg), and 3/8" square on the other end with some machining on a lathe. The inner part of the flexible coupling slides right in.
https://engineering.purdue.edu/people/brett.j.bell.1/300TD/VNTPics/ExducerAdapter
Here is the whole mess installed. I used a GM 3.8 air box which fit very nicely in front of the turbo. No K&N for me thank you very much. I also used a 240 oil separator (not finished in pic). The vent gas will go into the clean side of the air box in place of the OEM pressure transducer?
https://engineering.purdue.edu/people/brett.j.bell.1/300TD/VNTPics/Complete1
Also if you look close in this pic you will see the boost limiter on the intake manifold, which cracks open at a given psi and bleeds off vacuum to limit boost.
https://engineering.purdue.edu/people/brett.j.bell.1/300TD/VNTPics/Complete2
Finally, the modified VCV. I disassembled a VCV and bent the linkages as shown. This just reverses the rotation of the shaft with pedal travel
https://engineering.purdue.edu/people/brett.j.bell.1/300TD/VNTPics/VCV1
https://engineering.purdue.edu/people/brett.j.bell.1/300TD/VNTPics/VCV2
This is the schematic of how it works
https://engineering.purdue.edu/people/brett.j.bell.1/300TD/VNTPics/VNTcontrol

The schematic does not work for me.

Looks good!

I can see the schematic but not the pictures... :( Turbo surge happens when the engine RPM is too low for the amount of air the turbo is trying to move. This happens when it's lugging in a particular gear below a given RPM. On my truck it sounds like ch-ch-ch-ch-ch-ch with the pitch going up with the throttle position, sometimes morphing into more of a woo-woo-woo-woo sound at higher power levels.

In my case, the limits before surge are no more than 10 PSI below 1800 RPM and anything goes above that.

I On my truck it sounds like ch-ch-ch-ch-ch-ch with the pitch going up with the throttle position, sometimes morphing into more of a woo-woo-woo-woo sound at higher power levels.

:D :P

http://img.dailymail.co.uk/i/pix/2007/07_02/thomasDM2407_468x377.jpg

Looks good!
Thanks!!
I changed the images to urls maybe that will work :mad:

Installing a blow off valve will remedy any compressor surge. Not a cheap one that makes a huge WHOOOSH every time you let off of the throttle, i mean a good solid tial or greddy BOV.

Installing a blow off valve will remedy any compressor surge.

Adjusting the minimum vane setting (should be a little set scre under the lever) is the easiest remedy. Having the vanes just a little more open from the start will reduce backpressure on acceleration and get rid of the surge.

Thanks!!
I changed the images to urls maybe that will work :mad:

Yep, they work now.

They don't work for me. It says file not found.

Same here, file not found except the schematic.

EDIT: I think its not allowing direct linking. Entering the link while on the 404 page displayed the pictures.

Can everyone see them now?

Can everyone see them now?

I can now! Thank you!

What are you using for the air filter Fram? Nice setup, I will almost certainly be doing this soon. What did you do for the exhaust?

So the VCV increases vacuum as the pedal goes down?

What are you using for the air filter Fram?
Yes
What did you do for the exhaust?
I made an adapter I think its the third pic
So the VCV increases vacuum as the pedal goes down?
Correct. The position shown in the pics is the position at WOT. In this position there is little pressure on the valve from the spring so the vacuum signal is high (15 mmHg in my case).

Yes

I made an adapter I think its the third pic

Correct. The position shown in the pics is the position at WOT. In this position there is little pressure on the valve from the spring so the vacuum signal is high (15 mmHg in my case).

Whats the model number on the Fram, I really hate my over priced cheese cloth.

Did you use the stock actuator, it looks like it but I can't tell?

Install looks great Bajaman, nice job...


:D :P

http://img.dailymail.co.uk/i/pix/2007/07_02/thomasDM2407_468x377.jpg

Yeah, that's it! I should stick a mic up under the intake and record the sound. It's pretty funny.

Installing a blow off valve will remedy any compressor surge. Not a cheap one that makes a huge WHOOOSH every time you let off of the throttle, i mean a good solid tial or greddy BOV.

I'd be curious to see how you'd hook this up. I'd love to get rid of the surge on the truck.

I also hate "air strainers". There was no way I was going to put one of those pieces of crap on there. Most 3.8l equipped cars use the same air filter. I got this one out of a late ninety's LeSabre. I looked at several other buicks and they were all the same. The Volvo air box is very slightly larger, but the location of the ducting on the 3.8 box is basically perfect. Actuator is stock, though I had to clock the compressor housing a little to clear the intake manifold.
Thanks for the complements guys. I still can't get over how much of an improvement this made.

Based on your description it doesnt sound like surge(another poster was accurate in the chuffing sound). When the vnt opens fully...ie: low boost, the exhaust will drone. A really annoying sound. The right resonator will correct resonator will eliminate this sound. Are you running a straight pipe?

Stock exhaust. I believe this is an accurate description of what is happening.

I'm not sure the 3.8 airbox has enough filter area for the 617. It has quite a bit less area than the stock filter.

I'm not sure the 3.8 airbox has enough filter area for the 617. It has quite a bit less area than the stock filter.

The K&N barely cut it compared to the OEM filter. I hope the fram is as good but cant find any numbers.

What was the model on the fram filter? Or the GM Delco part number?

I think FI earlier posted a link as to the flow capacity of the 3.8 filter housing, and it was IIRC 450cfm. A K&N will "help" this, but it HAS to be clean. Don't overoil it as the 240D sep unit is underrated for a high boost 95X. If you use a paper filter you will turn it into a oiled filter soon enough...

Don't overoil it as the 240D sep unit is underrated for a high boost 95X. If you use a paper filter you will turn it into a oiled filter soon enough...

There is no MAF to hurt by over oiling the in these cars. Oil away!

More oil is not better on a K&N.

Por que?

I used the 3.8 box because thats all I could find that fit and wasn't an oil gauze. Also, it will allow me to have a cold air intake. If I can find something more suitable, I will surely put it on. I may have to resort to making something that uses a cylindrical filter??

You should be able to make a hose from the snorkel to the box inlet.

Por que? You want an even light coat of oil on the filter and then throw some dust on it to dirty it up.

Well my latest MPG figures are in. I recently drove to Chicago and back 245 miles mostly 65-70 with the AC on about half the time, and about 1.5 hours of stop and go, used 8.53 gals = 28.7 MPG!!. That is an all time high for me, usually it is closer to 24-25 range. I can say with confidence this gave a solid 3 MPG increase. Incidentally, odometer seems to be within 1% according to a 60 mile stretch of freeway.

That's great! There's a lot of satisfaction to doing a mod with so many benefits. Do you have a boost gauge? Do you have any before/after boost level data? How many PSI you running at highway cruise?

Yes, boost was 2-3 cruising at 65 with AC. Boost was in the same 2-3 psi range at 70 without AC. EGT was about 650 *F Exhaust pressure was around 8 psi.

Interesting. My setup with the same turbo puts out 4-5 psi at 65 mph, but my exhaust pressure is 6-7 psi.

Really. Cruising with 2-3psi, the exhaust should be under 5psi. Exhaust:boost pressure ratios above 2:1 are not great for efficiency.

Well the gauge is a 100 psi gauge, so low ranges are probably not very accurate. Also, I wonder if the measurement location has anything to do with this discrepancy. I am measuring this pressure in the necking region between the manifold and the turbo flange. The pressure would naturally tend to increase in this region. Maybe I will try to measure it in the EGR port and see what I get.

That could be why. Gauges are least accurate in their extreme (high and low) measurement ranges.

How about your pre-mod cruise boost levels-how do they compare to your current levels?

I made a quick measurement of the exhaust pressure last night in the EGR port. These measurements were closer to what bgkast reported: 3-4 psi boost 8 psi exhaust; 11 psi boost 20 psi exhaust. I also made a quick manometer and measured the pressure drop across the filter. 11 psi boost 4500 rpm the vacuum was 2.5" H2O. That's pretty good in my book. Pre-mod boost at 65 was in the 4-5 psi range.

What model VNT turbocharger?

Garrett GT2056V off of a jeep liberty CRD

Whats the max boost the Garrett GT2056V can run? I'm assuming the Jeep guys are running over 20psi tuned. Whats your max PSI you see on your Mercedes?

I run a max of 15 psi right now. It can put out much more, but I don't have the fuel to use it.

I think 15-17 psi is about the max anyone that's modified a 617 runs. There may be a very small # of exceptions, but in order to use that extra psi you'll need to alot of things beforehand.

Anything over 20psi will require better valve springs.

At least in the exhaust. Once you get over 30psi exhaust pressure the valves start to get pushed open.

Springs shouldn't be much of a problem to get if you want some. Take a pair to a performance shop (a real machine shop, not a ricer parts-swap shop) and see if they have or can make anything to match the spring rate needed.

I'm running a Holset HX30 with wastegate that opened (when new) at 27psi. The gauge I currently have only goes to 16psi, but it goes waaay off the deep end of that one all the time... Maybe I should get a bigger gauge. Should I worry about my valve springs?

I would look for a lighter wastegate, no way you need 27 psi of boost, and your turbine inlet pressure is probably around 50 psi.

You are likely floating your exhaust valves, which cause a power loss and can erode your valve seats.

As well as piston-valve collision.

Is there any way of knowing that you are floating your valves from too much pressure?






In a side note I have to tell... this is the 1,500th post in this forum!:D

High RPM misfiring, black smoke or piston contact.

Baja,

I did some test fittings this weekend. How were you able to clock the turbo up and still use the stock diaphragm? Also what did you do for the oil lines? Also, did you use 2 of the accordians to fit the exhaust manifold up?

I did some test fittings this weekend. How were you able to clock the turbo up and still use the stock diaphragm?
Yes, but it was tight. Are you planning on using a 115 intake or modified 123 intake? Basically I clocked the compressor housing so that the actuator rod would just clear the oil supply, and adjusted accordingly. Also, my exhaust flange adapter was made of 3/4" so that gave me an extra 1/4" if your using a 1/2" adapter.
Also what did you do for the oil lines?
I made my own with a combination of parts. I happened to have some 1/4" SS tubing with swagelock fittings. For the 12 mm banjo (oil filter end), I used an old one I had laying around and reworked the threads so that the swagelock fitting would thread on. The other end I welded a 3 AN fitting on and used this (http://www.jegs.com/webapp/wcs/stores/servlet/ProductDisplayPopup?storeId=10001&catalogId=10002&productId=744528&itemId=277370&langId=-1&showValue=1) from there to the turbo
Also, did you use 2 of the accordians to fit the exhaust manifold up?
No, just one and my adapter. There's a pic of the adapter early in the thread.

Unfortunately, something gave out yesterday, and now It sounds like there is air escaping somewhere when I get to about 12 psi. I thought at first that one of the hoses came off, but they are all intact. I haven't had time to pinpoint the problem yet.

I finally got around to finding the problem. Turns out I developed a hole in the resonator. I have never heard this type of sound coming from an exhaust before, just like air coming from a spray nozzle... I was driving myself nuts trying to find a problem in the intake. I replaced the resonator with a straight pipe, and can tell no difference in noise level.

So the 10mm hole is the fill side and the flange side is the drain?

Whats the blue hose to copper line for in the pics?

Well, you guys scared me, especially forced talking about black smoke, high rpm misfiring, and bashing holes in pistons, so I guess I'll turn the boost down to 15-17psi from the 20-25psi its been running.. Although I haven't had any complaints from the engine pulling 23ish psi at 4800rpm... yet... although your points are all well-taken, and the extra stress is not productive as far as the engine is concerned. Sorry to jump in with a side topic.

BTW: What might tighter valve springs do as far as cam wear is concerned?

So the 10mm hole is the fill side and the flange side is the drain?

correct

Whats the blue hose to copper line for in the pics?
That's for measuring exhaust pressure. I wouldn't worry about it if I were you.