TDI Town & Country

The valve you describe has 3 fittings. From memory, the top fitting is from the vacumn supply, the one directly below it goes to the dashpot on the turbo, once vacumn builds up, the turbo is pulled to full boost position, if an over boost condition is sensed, the valve bleeds the vacumn off through the fitting on the opposite side of the valve. I have a beetle fuel filter to keep dirt out of it. Stock, it was vented into the air intake. This is an oversimplified explanation of the system. Regards

VeeDubTDI, yes I know, my engine is an AHU with a standard wastegate. The details were scrambled in there, sorry. I bought a boost controller solenoid off an ALH with a VNT thinking it would work. I'm not sure it will work now and I'm looking for someone to explain how the VNT controller works.

rsxsr, that sounds about right. When you say "the turbo is pulled to full boost" that means they apply full vacuum to the VNT to get full boost, right? Then to reduce boost, they pulse the VNT controller which bleeds off the vacuum. Through experimenting I found that if you pulse the VNT solenoid, the vacuum will bleed off through the fitting marked ATM. This seems to match your description.

I'm still thinking this solenoid might just work though. If the VNT is pulsed to relieve vacuum and thereby boost, then in order for this valve to work in *my* vehicle, the AHU wastegate would also need to be controlled in a similar manner - pulsed to reduce vacuum/boost. I think I need to sniff the signal on my neighbor's AHU.

Why don't I just get an AHU wastegate solenoid? Good question; can't find any for less than $60 for one thing. I got the VNT solenoid for like twenty bucks last year. Anyone care to swap?

Thanks!

Travis

Travis, I am no expert, but we did camp near a Holiday Inn Express once.

When you say "the turbo is pulled to full boost" that means they apply full vacuum to the VNT to get full boost, right

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Yes, by default in my testing full vacumn pulls against the VNT diaghram and would be considered full boost or full on. My donor engine had sat so long, the linkage was almost seized. At one point I had an overboost condition and the engine would go into "fail safe". Cycling the key seemed to clear until the next overboost condition. I traced the problem to the valve you are asking about. I cleaned it with silicone spray and compressed air. Once I figured out the operation, I added a fuel filter to the vent to act as a mini air filter. I have not had the problem since. I am not familiar with the earlier setups that have an ECU monitored waste gate. Would it be possible to add an adjustable Pop off Valve to the intake side that could be adjusted to bleed off too much boost? That might address any overboosting and confuse the ECU enough to think the wastegate is working. mark

Adding a blow-off valve to the intake is not the proper way to "control" boost. For one, it has the potential to damage your turbo when it's operated as a substitute to the wastegate because the turbo is trying to pump the same amount of air that it was before (or more!), which can result in operating the turbo outside of its designed compressor map.

Fix the wastegate properly. It's easy enough to do, and it doesn't exactly break the bank. If you have to pay $60 for a part that works, that's $60 well-spent. I don't know if all of the N75 valves are the same, but it's worth a shot to see if the one from the VNT turbo will work on a wastegate turbo.

By the way, "ATM" stands for atmosphere, which is where the N75 is supposed to vent to (or from?). Put a little filter on there to keep it from drawing dirty air into the vacuum system.

Hey thanks guys; full vacuum to the wastegate = full boost in either vehicle. That's a good start. Now, how does the VNT bleed boost? In my testing, simply removing power from the solenoid does not bleed the vacuum. Like I said, it seemed like you had to pulse it.

I did get the chance to turn a wrench on it tonight. I think I have the intercooler ready to be bolted on





I'm going to have to relocate the horns as they were pulled to make room for the IC. No biggie. The factory IC piping fits almost to a 'T'. There are a couple of joints with a little stress on them that I will have to monitor. Also, the aluminum tube right off the turbo is having some clearance issues with the A/C line at the firewall. I may have to fab a new pipe from the turbo up to the plastic tubing.

Here's where the IC sits in relation to the nose of the van. There is an opening above the fog lamp, but it may not be quite sufficient. I'm thinking a small, narrow air scoop right at the lip of the air dam may be needed to flow air over the IC. Then I may have to slit the fender liner to let the air back out.


Also, I got the clutch reservoir mounted a while back, just didn't get pic's.



It's off a Yamaha R-series crotch rocket. I just needed a small little reservoir (I threatend to simply use a hose with a vent at the top!) I harvested this off eBay new for like $10. It has a little mounting tab with a metal sleeve insert; perfect.

Later!

Travis

I hope you make a You Tube of this beast running.

Fuel Line Question

OK, so I'm rerouting the fuel lines and remembered something my TDI buddy told me about - folks out here on The Club like to replace their fuel line with the stuff that dirt bikes and snowmobiles use....is that right? I did a search on the bulletin board and didn't come up with anything. Can anyone confirm or deny this? Someday soon I plan on running veggie in the TDI, so I want something that will tolerate that.

I was also wondering about other convertors out there - did you put any stress on the rigid plastic fuel lines with the new location of the FF, assuming it is not in the stock location. I can't mount the FF without stressing those little lines, so I'm looking at R&R'ing them (thus my question above).

Thanks!

Travis

Did you figure out how to control your boost? If not I would suggest a KISS (Keep it simple stupid). On a gasser if you are trying to control boost you just run the turbo up to the pre-defined boost setting then open the wastegate. You can do this with a cheep machinical valve, or a fancy boost controler made for a gasser. Those items don't care if you have a gas or diesle motor. Check out the links below.

The frist one listed I used in a gas motor to control 18psi on a turbo dodge spirit R/T. Worked great. I guess the only thing that would be differnent is these things need to be piped to see the pressure that is in the intake.

http://cgi.ebay.com/ebaymotors/High-Quality-Manual-Boost-Controller-VW-BMW-Mazda-SRT4_W0QQcmdZViewItemQQ_trksidZp3286Q2ec0Q2em14QQhashZitem335579b4b3QQitemZ220477371571QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

http://cgi.ebay.com/ebaymotors/GREDDY-PRofec-B-SPEC-2-ELECTRONIC-BOOST-CONTROLLER-SILV_W0QQcmdZViewItemQQ_trksidZp3286Q2ec0Q2em14QQhashZitem5ad33fa66aQQitemZ390091220586QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
http://cgi.ebay.com/ebaymotors/Turbo-Boost-Controller-Red-Universal-Integra-Legend-EVO_W0QQcmdZViewItemQQ_trksidZp3286Q2ec0Q2em14QQhashZitem3a529fa3b7QQitemZ250494297015QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Very nice! Haven't had time to do much with the Saturn TDI lately, but I am looking into signal converters from Dakota Digital to correct the speedo/tach readings, and I have an Autometer boost gauge to install. I still need to replace the radiator, and I made some brackets to secure the intercooler, just need time to install them. BTW, I like how yours fit up, looks like a factory item!

It sounds like you're looking for Viton fuel line, which is biodiesel compatible... McMaster Carr has it.

Hi,

Yes, I've seen Viton hose before. I was actually going to use it on my Greasecar, but sticker shock research lead me to Dayco Gen II fuel injection line. It is Buna-N (IIRC) lined with Viton, so it is kind of a hybrid hose and is cheaper than pure Viton. However, I was looking for a different alternative yet. Apparently no one here has heard of using the translucent fuel line like snowmobiles and dirt bikes and such use. I'm not sure of its composition, so I probably shouldn't use it.

Thanks gusy,

Travis

Oh - boost control. I found a solenoid in my pile of Mercedes parts. It is a 3 way vacuum solenoid. I powered up the beast today for the first time in a while. This solenoid is definitely noisy; you can hear it being pulsed before the ignition is turned on. Which, by the way, leads me to believe that it is similar to the boost control solenoid I have for a VNT. More experimentation to follow, but first things first, I need to plumb in my boost gauge.

Thanks for the recommendation on the mechanical boost control. I'm a big fan of keeping it simple, especially for reliability sake. However, utilizing the ECU control for boost control is probably the safest route for now.

Thanks!

Travis

Power Steering Progress

A big milestone today; the power steering has been Frankenstein'd. I went to Custom Hose on the south side of town yesterday and they did a fantastic job coming up with an adaption scheme. The new lines and fittings only ran me fifty bucks, so that was good too. Here's what we came up with:



And a brief 25" from the pump, here is where the new pressure line was fit to the Chrysler line:



The return line was simple; 5/8" hose up to a T that goes to the rack, from the pump, and from the reservoir.

Be sure to check out my Gallery for more pictures and detailed explanations.

I would have taken it for a spin today but a few last minute items came up. One of the brake lines decided to corrode and spill its guts (common problem on Gen III Chryslers w/ABS - right next to the SS flex lines). And the old power steering reservoir was coated in what must be remnants of the old fluid; it turned to something akin to molasis with an attitude. So that is soaking. Should be a few days and I'll take it for a spin. Oh, and I want that boost gauge installed to make sure I don't over boost due to miswire.

Travis

what kinda PS fluid are you using?

PS Fluid

Well, as of right now, the PS lines are empty while the reservoir and return line are soaking to clean out the varnish. You have a recommendation in mind for me? I know Honda has special PS fluid, but didn't know if there was a special VW formula.

Thanks,

Travis

VW does have a special formula... Pentosin brand something-or-other.

I've run dextron in one or two VWs before learning the hard way that PS racks are the weak link in the PS system. The VW racks will puke a seal after extended periods without the correct fluid. I'd recomend using what your rack requires.

Ifg the pump ever dies because of the fluid you can always use a mk3 2L PS pump as they are the same and very plentiful.

BTW Nice Swap. I'll be addinga link in the Conversion thread if you don't mind. I'd love to a see an engine bay show of how it looks now that its driveable.

PS Fluid

I did peruse a VW Passat owners forum and a few of them seemed quite adament we use the Pentosin fluid becuase of pump reasons, not rack reasons. I'm thinking it certainly can't be that big of a deal, can it? Maybe I'll go to the racing shop and see what they have, otherwise I'll just use a good brand of off-the-shelf fluid for now.

And no, I don't mind at all a link in a conversion thread. I seem to remember seeing one already though and mine was in there. I was honored; no biggee. I'll try to get some better pictures soon.

Travis

You'd think it's not a big deal, but it is. The VW stuff isn't really that expensive. The problem you're going to have is finding a fluid that works with the VW pump and the Chrysler rack.

Used pumps are common and easy to replace. Racks on the other hand are pricey and difficult to replace. If it were my labor and my dollars I'd get the fluid ment for the rack and roll the dice on the pump's life.

Oh - one more data point last night - I fired it up with a boost gauge. Just revving it in the garage (not getting too out of hand of course) I hit ~17 psi. It seems the boost controller is working for now. I'll definitely be monitoring that gauge closely during shakedown runs.

Travis

Hey, thanks for the pump advice; good to know. I agree - I'll roll the dice on the pump. Though the rack does have 110k miles on it and is showing a little weeping. Even then, I've used "seal conditioner" with good luck on my Honda.

And I don't know where you shop, but I can't find the Pentosin for less than $20/liter. That isn't very cheap in my book; do you have other sources?

Thanks!

Travis

Frankendiesel said:

Hey, thanks for the pump advice; good to know. I agree - I'll roll the dice on the pump. Though the rack does have 110k miles on it and is showing a little weeping. Even then, I've used "seal conditioner" with good luck on my Honda.

And I don't know where you shop, but I can't find the Pentosin for less than $20/liter. That isn't very cheap in my book; do you have other sources?

Thanks!

Travis

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I get my coolant and PS fluid from the dealer for next to nothing, but I know a few people there

I would stick with what was in the van before, probably ATF4+. If the pump screws up getting and fitting another one is easy. Replacing the rack when the seals fail is not.

-Jason

The racing shop has Joe Gibbs synthetic PSF for $12/quart. Half the price of Pentosin. Certainly the Chrysler rack won't mind it. Might just do that.

ATF+4 in the PS system? So they just re-label the tranny fluid and call it PSF? I could see that happening, but I'm questioning it nonetheless.

Travis

Chrysler and older Mercedes systems use transmission fluid for the power steering. It's cheap and plentiful.

17 psi just revving with no load seems like a lot to me.

yes there's a special VW formula.

I'm not sure which way I'd go since you have to be concerned both with the VW pump and the Mopar rack. I'd probably roll with the fluid spec for whichever part is harder or more expensive to swap if it starts leaking due to eaten seals.

You think that may be a bit too much boost eh? Well, I live on a long hill, I'll test it gradually opening the throttle. I suppose you are right; full boost with no load is probaby an issue.

Thanks

Travis

mr.mindless said:

yes there's a special VW formula.

I'm not sure which way I'd go since you have to be concerned both with the VW pump and the Mopar rack. I'd probably roll with the fluid spec for whichever part is harder or more expensive to swap if it starts leaking due to eaten seals.

Click to expand...

The easy fix for this is to just mix it 50/50, then the rack is happy and the pump is happy!

Just kidding, I know some vehicles are very picky about stuff like that, Jeeps and dodges I think have to have a special fluid in the clutch cylinders, where most cars just use ATF.

Ive run atf in my Toyota steering system for years with no problems, it leaks and no way Im paying $900 to fix a little leak on a vehicle with 300K on the clock and neither am I paying thru the nose for the special fluid.