My AHU Corrado VNT GT1749va Turbo Build Thread

Mark@MaloneTuning said:

Go kick his ass for me.

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Bwhahahaha.

I'll see him in an hour. I'll be sure to pass that along.

My fuel economy was great at 53mpg over 550 miles.

This evening I heard the telltale hiss of my rubber intercooler hose when I stepped on it this evening. Time for me to step up to samcos. 20year old rubbers hoses don't hold up well to 20+ psi. My ALH with an 1856 turbo went through 2 rubber hoses before I bought samco hoses for it and solved the old rubber hose issue.

Racked up another 520 miles and the fuel economy was 58.46mpg(my all time best). I was using hypermiling techniques. I think my normal driving mileage will probably be low 50s, but I'm confident that I can get 60+ on a long trip with no stops.

Very impressive! I've been knocking down 64 mpg out of the Saturn TDI, then started experimenting with advancing the IP timing a bit in the ECU...hoping to get into the upper-60's with it. As of today I've gone 352 miles on half a tank, so it looks like I might get there.

CFM said:

Very impressive! I've been knocking down 64 mpg out of the Saturn TDI, then started experimenting with advancing the IP timing a bit in the ECU...hoping to get into the upper-60's with it. As of today I've gone 352 miles on half a tank, so it looks like I might get there.

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Thats sounds about right for something with better aerodynamics. 2 or three of my trips on the 58mpg tank had 60-62mpg averages.

The reason why I'm not pushing my tank into the 600-800 mileage range is because my AHU Jetta sending unit does pick up the last 2 gallons in the tank because of the G60's sending unit locking ring. I'm thinking in the future I'll be switching back to a fuel pump with a holly by-pass FPR like I did on my first tdi corrado. Right now I just don't feel like spending the money on a new pump and sending unit.

G60ING said:

The reason why I'm not pushing my tank into the 600-800 mileage range is because my AHU Jetta sending unit does pick up the last 2 gallons in the tank because of the G60's sending unit locking ring. I'm thinking in the future I'll be switching back to a fuel pump with a holly by-pass FPR like I did on my first tdi corrado. Right now I just don't feel like spending the money on a new pump and sending unit.

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I was working on installing a MK4 fuel pickup. It is normally to long but I cut the locking tabs down so that it can compress further. The 2 remaining issues are the fuel level sender which works reverse of the MK3 sender and the fuel connections are not the same. If this can be modified to work then a PD lift pump may also be modifiable. The PD lift pump has the same issue with being to tall.

Minor Update,

I had a spreadsheet that I used to keep track of a lot of the parts and pieces for my engine rebuild and turbo upgrade. I cleaned it up and uploaded it so it can be of use to others. It includes prices, part numbers and sources. Feel free to use it as a guide please don't point out that if I had done things differently I could have saved money or ended up with more power or potential. I ended up with what I wanted and I'm very satisfied with the end product.





My car has been off the road for a number of weeks because the EGR inlet flange's gasket popped out. When going into replace the gasket I saw the flange had a minor crack because I ground it to thin when port matching it so I had a friend weld it and cut an o-ring groove. It was damaged when the o-ring groove was cut and my friend ended up making a billet flange. I just got it back.

In the mean time I removed the MAF's screen and cleaned up the transition for the air entering and leaving the MAF. I damaged the MAF's senser so I'll have to order a new MAF before I put it back on the road. Oh and this is the 2nd MAF I've fubared (thanks Ben). I think I've learned a lesson to not F with the screen or housing Time to order a new MAF unless somebody wants to hook me up

Houpty GT said:

I was working on installing a MK4 fuel pickup. It is normally to long but I cut the locking tabs down so that it can compress further. The 2 remaining issues are the fuel level sender which works reverse of the MK3 sender and the fuel connections are not the same. If this can be modified to work then a PD lift pump may also be modifiable. The PD lift pump has the same issue with being to tall.

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I used a PD lift pump in a mk3 2.0 sending unit with a 5/16" T of the vertical PD pump which is how I got around the height issue. I still have to pull the sending unit back out to modify the pickup further so It will use the whole tank..I end up running out by the time the low level light is on..luckily I don't generally use the reserve but you never know when it may be necessary
best part is the gauge works properly

Nice spreadsheet. lots of good info there.

Regarding the MAF. Mark can set you up with a MAF delete tune pretty easily. I've been running one for many months.

Jon

But, don't you still need a properly functioning MAF? The tune reads off the MAP, as I understand it, but you still need a good MAF.

not true. There is an aluminum tube in the place my MAF use to be, the MAF is now just sitting on a shelf somewhere.

Yep properly tuned maf delete means that you don't need it there at all.

Thanks.

What tune(s) are you two running...?

I'm running a Malone Tune AHU-VNT tuned for 21psi.

GTiTDi said:

I used a PD lift pump in a mk3 2.0 sending unit with a 5/16" T of the vertical PD pump which is how I got around the height issue. I still have to pull the sending unit back out to modify the pickup further so It will use the whole tank..I end up running out by the time the low level light is on..luckily I don't generally use the reserve but you never know when it may be necessary
best part is the gauge works properly

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Do you have any pictures of the tee? Did you mean a elbow? I have seen others cut or buy the plastic fittings from the MK4's and slip the hoses over them. Does anyone know if those right angle connectors are available separately somewhere?

The VR6 tank is 2 deep for the MK4 equipment based on what G60ing has said. I have also read that there are different types of 4 cylinder Corrado tanks or at least 3 types of fuel pumps that were originally put in the tanks. My G60 tank is too shallow for any unmodified MK4 fuel pickup even with the lock ring at the bottom of the tank removed. The G60 tank is several gallons smaller than the VR6.

Would the early 1990 intank transfer pump from the 2 pump system provide good pressure for the TDI?

It is a simple 5/16" barbed tee, I capped off one end. I don't think it requires photo documentation. At least not until I remove it from the tank!

I finally got around to some data logging with my local malone tuning rep Ben(bengone1) the other day and here are the results:





Ben emailed the files to Mark and before I arrived home Mark had the charts to me with his input. He provided some fueling advice and I've since pulled my case relief valve and found the clip part way out after fixing this the car feels much more robust throughout the power band. So Ben and I will be data logging again very soon. Then Mark can make a few minor tweaks to what I consider a very good feeling tune.

I should note that my car doesn't have a boost valve installed.

Frank,

I had similar IP timing issues, both from the case relief valve and from air being pulled in through my thermostatic T on my CAT adapter.

It looks like you just need a minor tweak to your N75 duty cycle to make your actual boost match requested. More fuel might help too if you're not maxed out already.

I just got a new tune this morning for my BV43, boost comes up fast and nails request without going over, no boost valve here either.

Log channel 7 and 11 at the same time and do some 3rd to 4th gear pulls to see what your intake temps get up to. I had a theory that heat soak was causing me to loose timing on the top end but I did some pulls yesterday that showed me otherwise. I got up to 60C when trying to get the temps up.

The clip slides in easily enough. But it usually just comes out again after sufficient flogging. That's why the "keystone mod" was created. I'm at work and can't show a photo now. Do a search here and you should find it.

Stealth TDI said:

The clip slides in easily enough. But it usually just comes out again after sufficient flogging. That's why the "keystone mod" was created. I'm at work and can't show a photo now. Do a search here and you should find it.

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Found it Thanks:




http://forums.tdiclub.com/showthread.php?t=336421

JFettig said:

Frank,

I had similar IP timing issues, both from the case relief valve and from air being pulled in through my thermostatic T on my CAT adapter.

It looks like you just need a minor tweak to your N75 duty cycle to make your actual boost match requested. More fuel might help too if you're not maxed out already.

I just got a new tune this morning for my BV43, boost comes up fast and nails request without going over, no boost valve here either.

Log channel 7 and 11 at the same time and do some 3rd to 4th gear pulls to see what your intake temps get up to. I had a theory that heat soak was causing me to loose timing on the top end but I did some pulls yesterday that showed me otherwise. I got up to 60C when trying to get the temps up.

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We are going to redata log the car now that I've discovered the valve issue. It should be delivering more fuel now.

My MPG on my way in to work yesterday were 59.9 when before the best I had achieved was 55.

My intake temps during the data logging were low because the circuit we made for the 3 gear pulls was rather long.

I've had a shaft failure. Now to decide whether to stay with a stock 1749va, upgrade the broken GT1749VA, go with a BV43 or make the jump to a 17/22. Time will tell. I'll post pictures of the carnage in the performance section in hopes of figuring out why the turbo died at roughly 3k miles

Oh wow, that's awful news! Doesn't make much sense. I have considered upgrading my VA but not real sure of my options. Would love to keep the current manifold and turno placement so I do not have to modify the motor mount.

I guess now we know why VW's selling them for so little.

I hope that mine doesn't have this issue when I put it together...

all of the others haven't had problems, JFettig had one for a while before deciding to go bv43

Digital Corpus said:

I hope that mine doesn't have this issue when I put it together...

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If you are the least bit concerned then send it back and I'll refund your money otherwise its yours.

I'm fine with the sale and I'm sorry if it doesn't seem that way. I tend to be a bit vocal. I know the opportunity of getting one like this will most likely never happen again.

I'm just waiting for life to settle and money to come in to get the tune lined up and get oil lines, IC piping and the adapter, modified downpipe, and the tune to get it all in. While I wait I've already started port/gasket matching the exhaust manifold. And I am curious to see if any BV43's come around because I'm toying with the idea of making a hybrid turbo.

Hello,

Stealth TDI said:

I guess now we know why VW's selling them for so little.

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Sorry if that came off as fear-mongering. I'm a wise-guy and sometimes a cynic. I think Frank knows that. But many of you don't. I did not REALLY mean to suggest VW is clearing bad turbos out of their inventory. It's possible these turbos are so stinkin' reliable that they just don't sell many. So they put them on clearance to free up some shelf space.

Scott

Nah, I didn't read that as literal. I figured it was sarcastic. Thanks though.