Qwkswede's Red 740 Wagon. Part Deux aka Superfridge

[qwkswede]

I haven't touched a project thread in quite a while, but I am still tinkering with old Volvos. What can I say, some habits die hard. It's about time I start to organize a little memory book for this new adopted Volvo.

This 740 wagon came to me kindly in a time of need. I had just wrecked my hotrod but daily driven 244. There is a project thread on Turbobricks for that car. I really loved that little car. It wasn't a crazy race car, just a nice daily driver with some solid modifications. More info here:
https://forums.turbobricks.com/showthread.php?t=301350

OLD CAR


I pulled the engine and trans and scrapped the shell. I couldn't find another 240 to build at the time. They have become scarce and expensive all of a sudden. It was a bit sad.

A friend saw me moping around Volvo-less and offered me a free 740 Turbo Wagon. It had been sitting in his yard for 10 years. Full of wasps, spiders, mice. It had some hail damage. It wasn't perfect, but a good solid platform for a hot rod daily driver maybe? It didn't run, but there was a decent engine that he grabbed at the junkyard long ago and never finished.

So I took it home and tried to make a plan. Do I get it running as a stock driver? Bolt on some fun stuff from the 240 parts pile? Here are some photos from day 1. I have a bit of catching up to do from the last year. Stay tuned.

NEW CAR - AUGUST 2018 PICS






=========== Current Build List January 2021 ==============

• 1992 Volvo 740 Turbo Wagon Shell. It came to me in 2018.

Engine

• Junkyard B230FT. 1990 I think. 13mm rods and no squirters.
• Notched turbo pistons using Yoshifab tool
• Yoshifab 16v to 8v exhaust manifold adapter plate
• Yoshifab 16v conversion timing belt set
• B234 Cylinder head, intake manifold, stock A cams.
• 90+ exhaust manifold, ported
• Yoshifab heavy duty valve springs.
• CX Racing GT3071 ball bearing turbo, billet compressor wheel
• 3" Stainless exhaust, turbo to tail with catalytic converter and Magnaflow muffler
• 80 lb Siemens injectors

Electronics

• Megasquirt/Microsquirt ECU
• Electronic Boost Control
• Flex Fuel Sensor
• Factory Bosch ignition controlled by Megasquirt.
• Volvo 850 throttle position sensor
• Flex fuel sensor - Runs on E85, Gasoline or any ratio mix.
• PLX Wideband Sensor
• 3 bar map sensor

Drivetrain

• AW71 with accumulator mod
• Trutrac differential

Chassis

• IPD springs
• Bilstien Touring Shocks
• Kaplhenke Camber Plates
• BBS BMW wheels 17x8

[Harlard]

Boy oh boy, do I spot something sneaky in that last picture?

[qwkswede]

Originally Posted by Harlard

Boy oh boy, do I spot something sneaky in that last picture?

yep yep. I'll get some more details added. I can only crop pictures and type so fast. But for now I'm going to enjoy this cold boost friendly weather and do a burnout in my Red Wagon.

[Harlard]

[qwkswede]

I started this thread a year ago just after bringing the car home, and it came together pretty quickly. But, I got busy with other things and forgot all about this thread. Life happens. Pandemics happen, etc. But like everyone in the world, I'm spending alot of time around the house these days and alot of time in the garage. So it seems like a good time for an update.

Just to recap. Alot of parts like the engine were pulled from my wrecked 240. I combined those with a bunch of other parts from my basement stockpile. I also bought a few parts from Yoshifab and other places to make it an interesting runner.

Once it ran, I didn't really do much more work. I drove it and fixed some minor issues. But it's been a fun weekend driver. I have a handful of photos taken as it evolved over the first year in my hands.

I Rented the piston notcher from Yoshifab and got to work on the shortblock. It's a high mileage motor turbo I pulled from a junkyard. The original 1992 motor was long gone when I got the car. I think this was from an 89 or 90 year car.


Here I am trial fitting some of the basement parts from my old 16V adventures.


I installed some upgraded valve springs and seals. Also from Yoshifab.


Here it is coming together. You can see the Yoshifab adapter plate for the 8v exhaust manifold, to make it easy and reliable for a daily-ish driver.


I sourced the tensioner and crank timing pulley from Yoshifab too.


I then welded up a nice 3" exhaust for it. I installed a catalytic converter and a single Dynomax muffler at the rear bumper.

[qwkswede]

I finished up the exhaust with a homebuilt 3" stainless dealio with a Magnaflow muffler. It has a 3" catalytic converter that's not pictured here. The goal is to get through emissions tests without any funny business.


Once that was done I started working on the Megasquirt setup. It's a Microsquirt unit that was used in my old car. It's been around a while and going strong. The pictures show the install stage that I like to call the Mega Mess. Wires all over the place. I built it as a plug and play style system. Thinking I might like the stock computers to go back in someday. I didn't cut any of the factory harness....

Features I set up right away...
MS2 Extra code
VR sensor from crankshaft for rpm signal
Batch Fuel with 80# injectors.
Ignition using through the factory ignitor, coil, and head mount distributor.
Boost Control Solenoid
3 bar map
Idle Control
Flex Fuel Sensor
Wideband O2
Maybe in the future some Nitrous and launch control too. I think I might have a free output or two still.

Pictures:

[qwkswede]

I got the car running and tried to back it out of the garage. That's when I discovered that the ring and pinion was somehow damaged in the 10 years since the car ran. I can only guess that it was towed with the transmission in gear at some point.



So I picked up some good used gears from the junkyard and a Trutrac diff from one of the online speedshops. I welded the trigger ring onto the new diff and installed it with some fresh bearings and seals. This is my first Dana 30 Truetrac in a Volvo. It's a wonderful looking diff.



And with that, I think it's ready for a test drive. Hopefully I can get it through an emissions test soon and get it licensed.

[qwkswede]

It took about 6 months or so to get the 740 running. There was tons of searching for oddball Volvo 740 16v parts that I didn't expect to need. Throttle cable, throttle body, and distributor come to mind.

I also bought aftermarket tail lights and headlight lenses for the car. And I cleaned about 20 hornets nests from the car. It was really disgusting.

For the first test drive I made a little 4 minute video. A little walk around and test drive clip with some good exhaust engine noises at the end.



Pretty stoked to have it up and running!


-KL

[Harlard]

I remember this

[qwkswede]

The first turbo I put on the car was a Garrett T3 that I had cobbled together. It had the Dodge Cosworth style turbine housing that bolts right to a 3" downpipe. These wastegates are really nice for an internal wastegate. I was hoping the small turbine would spool quick and the efficient wastegate would just let the exhaust flow at higher rpms. It worked to an extent. The car ran pretty good with this little turbo, but when I started turning up the boost I ran into some problems. I think the higher flow engine and tiny turbo was a bad mix. The turbine wheel RPM was probably astronomical as I was surely approaching 275-300 hp.



Turbo #2 - Ebay T3/T4 50 trim.
This was a turbo I bought years ago for $150. It has been OK on a couple different engines but never great. It just isn't very responsive. Even on this 16V turbo project. The combination of a tight converter, low torque 16V motor, with a slow spooling turbo was really not what I wanted. It would pull hard on the freeway. But from a dead stop on the streets it would take forever to spool. I was usually in 2nd gear and 4 or 5 seconds into a pull before full boost would hit.

January 2021
Turbo #3 - CX Racing 3071 Ball Bearing and Billet Compressor Wheel.
After talking to a few people on Turbobricks and considering my environment I decided to go for a smallish turbo with a ball bearing center. I live at 5300' altitude and often drive in the mountains at much higher altitude. Altitude really makes a difference in turbo spool time.

I decided to go this route and modify the turbine housing for my external wastegate location.


I did some work on the downpipe to accommodate the new turbo and wastegate. The wastegate from JGS turbo. It's a nice quality made in USA part that I have had around for a long time.


And here it is assembled and running again....

[qwkswede]

I finally got to do some driving and datalogging last night. The car feels very fast with the new turbo... I'll try to get out and shoot some video clips from inside the car this weekend.

Some thoughts.
The car is fast, but I have a boost creep problem now. Datalogging boost shows the gate cracks open at about 180kPa and 4500 rpm. And then manifold pressure rises steadily to about 220kPa as the motor revs toward 6000 rpm. It's just about 20 psi on the boost gauge at the top of the range.

What that tells me is this turbo is pretty free flowing on the exhaust side and my execution on the wastegate plumbing is maybe not flowing enough to keep up and control boost. I need to solve this problem. 20 psi is pretty fun but I'd like to be able to run 15 on gasoline and take advantage of the Flex fuel tune. It's a hoot at 20psi, and seems perfectly happy doing it on E85 for now. But yeap. I'm not really liking the runaway boost...

This is a milder case of the creeps in this image snapped fro the 1st to 2nd gear range. Longer pulls on the highway let the boost climb even more.



Second comment. I do love the way this car drives with the AW71. It just feels like a tame 740 in every way until you put your foot to the floor. The power delivery and drivability is great in every way. Now the turbo spools better and combined with the long runner intake manifold and a little tuning I have been doing the powerband feels good, and not so lazy when driving easy. Also the factory set 6000-6200 rpm shift points seems just fine in drive. It doesn't feel like I'm short shifting all the time. I could manually shift if I want to let it rev higher. But I don't know if that would help at all. And boost creep would probably be worse. I hope the trans survives a while. I don't feel any slipping shifts or weirdness now. I'm crossing my fingers. And I'm still on the hunt for an AW72L if I can find one. I hear that they are the strongest of the stock autos, and the lockup would be a nice improvement for highway driving.

[qwkswede]

It's a Ripper.

[Harlard]

Very cool. I should turn the boost up in mine and see how scary it gets.

[qwkswede]

Originally Posted by Harlard

Very cool. I should turn the boost up in mine and see how scary it gets.

Yeah! Do it and tell me how it goes.
At 18psi now, and I'm almost at the limit on the injectors. They are 80 or 100lbs.

[Texas240]

waiting for that 3-4 burnt aw71 clutch moment..

[linuxman51]

have you added timing to see if that helps with the creep? 60kpa of creepage is quite a bit. looking at the picture of the datalog tho, it looks more like it's set for 220 and that's where it's going, even after the shift it doesn't really drop much, but it doesn't also take off a whole lot higher up. what kinda bewst control ya running?


as far as the transmission, you'll probably have more trouble out of the 3rd gear (C2) clutches than anything else in there, that's what I kept blasting out of the aw71 in my 940 when it was running the 16v and the evo8 16g.

[qwkswede]

I have played with the timing in the 5500 rpm range somewhat. It does have an effect on the boost creep for sure. I was intentionally pulling a few degrees timing from the shift point rpms to soften the power and take it easy on the trans. And that made the boost creep worse. But even with flat timing of around 22 degrees in that 200kpa row there are boost control problems. Ideally I'd like to be at about 180KPa so that I can use 91 octane fuel and keep things alive. But that's not even close to possible right now.

I have megasquirt controlling a 3 port solenoid right now. The wastegate is a 38mm JGS. I have the top (add boost) port open to atmosphere right now. And I have the same problem running directly from the wastegate or with the EBC inline. The electronics are doing nothing right now, because I'm just sending full pressure to open the gate as it overshoots the set point.

The trans should be OK if I can get the power dialed down to a reasonable level. :-) I like driving the car with the AW71. So I think I'm going to work with it to keep it alive. I have other race car projects. This one is supposed be be more street friendly. Which is harder to achieve than I like to admit. I always enjoyed my old fast wagon more when I could take it on long trips and rip around the canyons.

Originally Posted by linuxman51

have you added timing to see if that helps with the creep? 60kpa of creepage is quite a bit. looking at the picture of the datalog tho, it looks more like it's set for 220 and that's where it's going, even after the shift it doesn't really drop much, but it doesn't also take off a whole lot higher up. what kinda bewst control ya running?


as far as the transmission, you'll probably have more trouble out of the 3rd gear (C2) clutches than anything else in there, that's what I kept blasting out of the aw71 in my 940 when it was running the 16v and the evo8 16g.

[qwkswede]

@Kenny,
That picture above the boost target was 200, I have that line displayed there too. Actual boost was climbing to 222 at the peak. On longer pulls in 2nd gear, the boost will climb to 235 where I have the overboost cut set. That's always fun to hit. FULL POWER followed by face hitting the steering wheel when the power gets cut.

And it's the same boost curve even if I have the setpoint at 180. It's closed loop control which was working quite well on the old turbo. I usually have good luck with it. It's not really playing a factor at all here yet.

[Duder]

Hey Ken, good to see your progress! Looks like a fun car for sure and a bit of a handful on the cold roads! Turbo-wise, a 3071 is a great match for a 16V redblock and it sounds like you're enjoying it more. Did you have this car at Davis 2 years ago? Seems like a different lifetime now.

There may be a few different things going on affecting your boost creep issue, but essentially I think your wastegate probably just isn't able to flow enough. The fact that the behavior is the same running through the EBC or not is pointing that direction. If you could mount the wastegate at a more gentle angle on the inlet side, less than a 90 degrees to the direction of flow into the turbine housing that would help a lot, but maybe you're limited in packaging space. The effective flow through an external wastegate valve is cut drastically when it's at 90 degrees. The 38mm valve may also simply be too small given the other conditions and constraints. Would it be difficult to upgrade to a 44mm at this point?

Your comment about pulling timing making boost creep worse - that makes total sense. As you retard timing you're moving combustion later and later in the stroke, and increasing exhaust gas temps in general. If you go full retard then you end up with "external combustion" and the flame front makes its way out of the cylinder, you end up with more energy in the exhaust flow and an anti-lag effect. Great for keeping a turbo spooled up between shifts, not so great for controlling boost!

[Harlard]

Chris,

He has a similar wastegate setup as I do, being a 38mm gate flange welded directly to the turbine housing. Currently it produces about 185 peak tapering to 175 kPa at redline, using an 8 psi spring. I think a smoother gate outlet and merge, paired with a different gate spring would be enough to resolve the creep issue.

[Duder]

Originally Posted by Harlard

Chris,

He has a similar wastegate setup as I do, being a 38mm gate flange welded directly to the turbine housing. Currently it produces about 185 peak tapering to 175 kPa at redline, using an 8 psi spring. I think a smoother gate outlet and merge, paired with a different gate spring would be enough to resolve the creep issue.

Those changes should help as well. I was speaking in general terms / best practices, but of course there’s always more than one way to make it work.

Keep in mind he’s at much higher elevation which means his turbo speeds are much higher for the same boost pressure, all else being equal. The turbine has to work harder to drive the increased power requirement from the compressor, and that drives increased turbine pressure ratio and so increased pre-turbine backpressure. In other words an identical wastegate hardware setup may not work as well in Denver as it does in Portland.

[qwkswede]

Hey Chris,
This is a different wagon than I drove to Davis. This one hasn't really been up for a road trip since I have owned it. I just barely got the black widows and hornets cleared out after it sat in a field for 10 years.

Thanks for the wastegate info. I was suspecting much the same stuff with the 90 degree angle into the gate tube. I copied Harald's design on that :-), and it is in a tight spot between the engine and frame rail. I might have room for a larger diameter gate, but not much. My wastegate spring starts opening about 10psi, I checked that on the bench. And you can see the deflection in the boost curve in the chart above. It just doesn't do much to control the boost and everything stabilizes somewhere between 18-22 psi depending on rpm, time, etc. I guess that's not the definition of "stabilizing". But it doesn't shoot to 40 psi with the gate wide open either. It is really a 6-10 psi overboost situation, if the wastegate was working as intended.

I'm going to pull it apart and see if I can do some flow path work. Maybe open the hole to a larger oval shape and rebuild the inlet with an elbow facing the incoming flow. There really isn't much room there with the turbo mounted to the factory 90+ manifold. I tried to make the most of it, and that's why the gate is welded into the turbine housing. Maybe some room for improvement though. I didn't anticipate this would be a problem with a smallish turbo. Thought there would be plenty of back pressure that cracking the gate open would get the job done.

[qwkswede]

Another thing I was thinking about, maybe I just vent the wastegate pipe to the atmosphere. Though I'm not really interested in making MORE noise. That might help control boost though. I do have a catalytic converter and one straight through muffler in the exhaust. Seems like an open dump wastegate might be immensely more effective than merging back into the downpipe.

[Duder]

Gotcha Ken!

I think a stiffer spring won't eliminate boost creep in the top end, going back to that idea. The problem is that once the wastegate is full open, it can't flow enough exhaust gas to control boost. A stiffer spring will delay the opening point and possibly help a bit in that it won't have as much time to creep to the same level as today, but it wouldn't fix the root issue.

Any porting work you can do around the wastegate plumbing should definitely help.

And yeah, I think an atmospheric WG dump tube would also potentially improve the situation, if there's a way to do that cleanly without introducing more restriction somewhere. Another thing that in general will help with boost creep is making the main exhaust system more restrictive (although not really desirable). There are many cases I've seen / heard of where boost creep started for someone after they enlarged the post-turbine exhaust system. Removing restriction from the system is a good thing for engine performance since it reduces both post-turbine and pre-turbine backpressure. But what it means is that the turbine wheel needs to flow even less to make the same shaft power and control boost. Meaning the wastegate has to flow more. If the wastegate valve & plumbing was right on before upgrading, then stepping up in exhaust diameter can make it marginal and sometimes induce boost creep.

[Harlard]

Originally Posted by Duder

Those changes should help as well. I was speaking in general terms / best practices, but of course there’s always more than one way to make it work.

Keep in mind he’s at much higher elevation which means his turbo speeds are much higher for the same boost pressure, all else being equal. The turbine has to work harder to drive the increased power requirement from the compressor, and that drives increased turbine pressure ratio and so increased pre-turbine backpressure. In other words an identical wastegate hardware setup may not work as well in Denver as it does in Portland.

Big variable I was ignoring. Thank you for the clarification!