Hello everyone!

So, to get started I have (as the discretion says) a 1990 Volvo 740 GL Wagon. I bought this car as a daily driver and would like to maintain that... as well as m as make some improvements. Here is a list of things things I'd like to do with the car.

Convert to manual transmission from automatic.
Add a turbo.
Upgrade the exhaust.
Improve handling.
Improve acceleration.

Please, if anyone on here has any points on where to start it would be most appreciated.

 

find and buy a manual turbo car. if the turbo car's body is trashed, then transplant its entire drive train into your car. you'll want everything from the rear axle to everything under the hood, including the engine wiring harnesses, and the ECU and ICU which are in the passenger footwell.

the stock exhaust on a turbo is just fine unless you make extensive engine modifications. just upgrading to bigger exhaust and/or louder mufflers won't give you any horsepower. you need to port the heads, go for high lift cams, higher boost turbo, bigger injectors, higher volume fuel pump THEN upgrade the exhaust. all that stuff is quite expensive, also shortens the life of the car.

 

Finding a manual turbo car can be tricky, depending on your location. I never had much luck with that. Going auto to manual is a bit involved, but can be done. I did lat last year. My thread on the topic is for my 240, but it is similar on the 740--I know, because the instructions i initially found (and reference in my thread) was for a 700 series car. So this might be useful:
https://volvoforums.com/forum/volvo-...nd-swap-73389/

Turboing a non-turbo car is a bit more complicated. This is something I may do in the future, but I am in no hurry, because if done wrong (which most people do) it definitely shortens the life of your car. Parts also cost. Here is a thread on that topic:
Tb newb performance faq - Page 2 - Turbobricks Forums

As to handling... there are a myriad of things you can do. You could lower your car, with different springs and shocks. But don't do that--it is an abomination.
Easier, and probably more effective is just replacing tired shocks and possibly adding a stiffer sway-bar. I don't know that a stiffer sway bar in a 700 series car is that big of a deal--the 700 had a tighter suspension than the 200 cars, so whereas you notice a real improvement putting the sways on a 200, I didn't feel a huge improvement when my brother put a sway-bar on his 700. Anyway... those are my thoughts on the matter.

 

Thank you all for your replies!

Please excuse the "Glass upgrades" in the thread name. Auto correct must have gone and changed that while I wasn't looking.

Anyways...

Naturally, if I could find a turbo diesel with a manual transmission I would just buy it and turn it into my daily driver, but so far I haven't even been able to find a 740 model with a manual transmission, let alone one with a turbo.

Which brings me here. I am set on converting my beloved wagon into a manual for the simple reason that it is far more fun to drive. I've also heard that they last longer if you take good care of them.

So for my next question(I have not yet gone through the recommended threads, so this might be in there), what kind of transmission should I be hunting for and can I use a hydraulic shifter instead of rebuilding the center console?

Looking forward to getting this project started and thanks again for all your help

 

Volvo DIESEL?? ugh. The VW-based D24 was not a very good diesel engine, it was meant for small delivery trucks. I would avoid at all costs, if you want a diesel, get a late 80s, early 90s Mercedes 300D, the W124 model with the i6 turbodiesel. Or, the early 80s 300D W123 model with the i5 turbodiesel, but its rather gutless by comparision (the W123 has the old school round headlights, while the W124 has glass rectangular headlights and a more modern body design with MUCH better suspension)

the preferred manual tranny on a 240/740 is the M46, 4 speed + overdrive. the mechanical shift linkage and shifter and bezel/boot will just drop into your center console in place of what you got now.

you will of course need to install the clutch pedal assembly and clutch master cylinder from the stickshift 740 you source it from... you'll need to either use the engine from the stickshift car, or swap the automatic's 'flexiplate' with the stickshift 'flywheel', and since your car is a LH2.4 injection system, that has to be the flywheel from a 1989+ non-turbo or 1990+ turbo, unless you want to swap the whole engine management and fuel injection infrastructure back to LH2.2, that would entitle wiring harnesses and stuff. The engine wiring on 1983-1987 Volvos is bad news.

the later stickshift volvo 740/940's used a 5 speed M47 transmission, this is not strong enough for a turbo.

frankly, the Aisin-Warner AW70/71 transmission used in automatic 240/740/940 after about 1985 is an *EXCELLENT* and very robust transmission, they last a long time, and are relatively inexpensive to repair/rebuild (at least compared with modern computerized trannies, ugh!). This is essentially the same transmission used in 1983-2002 Toyota 2WD pickup trucks, as well as a variety of RWD Toyota cars in the 80s, like Supra Turbos.

 

My dad had 88 300D turbo diesel that we both loved! Had some awesome memories in that big brown German tank.

So you think I should pull the transmission from an older manual and then a newer flywheel? And has anyone tried a hydraulic clutch? I know its kind of cheating, but still it would be fun.

 

I've never had a volvo stickshift, but I believe the 740 sticks came with hydraulic clutches. I guess I'll have to look it up in the parts catalogs when I get home.

edit: home now... and yes, its a hydraulic clutch on a 740 with a M46 manual. the master cylinder is on the engine compartment side of the firewall, it shares the brake fluid reservoir.

the electric overdrive on these M46's is actuated via a quite different circuit than the OD on the AW70/71 automatics, you'll need the OD relays from the manual donor car.

 

That would make sense. I wonder if it is as easy as just swapping the relays. I guess we'll find out soon enough.

I may have gotten a little ahead of myself
in some aspects of the project. I had forgotten that I still need to fix a few things that have gone wrong with the Volvo.

Firstly, the passenger side windshield wiper is not working very consistently(I say consistently because until yesterday it just wasn't working at all. I can't really say why it just it started up again and then died again).
Also, the rear passanger side turn signal and brake light are on the frits. The fog light seems to be blinking as well when the turn signal is on and then stops when I have the brakes on, it then alternates between the turn signal and the brake light. Weird...
Lastly the odometer and speedometer have not been working for the last year... I have no idea how to fix that...

With that being said there is a guy about an hour away that I'll try talking to and see if he has any of the parts or even a manual 740 he is willing to "part" with (pun intended).

 

your tail light issues could be the ground at that taillight, or the wiring, or the sockets.

the odometer and speedometer are both fed from a sensor in the differential in the rear axle, and the wire is somewhat exposed back there, and can break.

the wiper, if you pry up the cap over the 'hub', there's a nut under there that holds the wiper arm onto the toothed shaft. its probably worth taking the whole arm off and cleaning the spline teeth, and the inside of the arm where it goes over the shaft. if the end of the arm is cracked, or the spline teeth are stripped, I believe you can still buy new wiper arms from Volvo, or go looking for one at a junkyard. put it on at the same angle as the other one, tighten the nut and snap the hinged cover back over it.

I'm pretty sure the manual OD is wired quite differently than the automatic one. it probably uses a different relay in a different socket. I can look this up at some point in time, but I'm not at my desk right now.... oh wait, I don't have 1990 740 schematics, only 940 from 1991 on (but its probably close enough, however, 1990 740's were a bit of a transition year, they changed stuff in 90 and again in 91 with the introduction of the 940 and yet again in 92 (bigger radiator, electric fan), then they were fairly stable until 1995 and end of production). The M46 electric overdrive circuit is probably pretty much the same thing, however, in any year with that transmission.

btw, if you do find a stickshift... the M46 just has gears 1-4 and a button on top for overdrive. The later and weaker M47 has 1-5 on the ****, and no switch.

 

Not for me.

 

I've never seen a manual 740 turbo personally, and I'm not sure they sold ANY manual 940 turbos in the USA. for some reason, manual wagons are rarer than manual sedans.

 

We had a 740 turbo wagon that was manual, and it is the only one I've ever seen. We got it because it had been on the lot for a while, and no one wanted to buy a manual.

Edit: I should clarify that this is when my parents were buying the car new.

 

ALSO--

I don't have wiring diagrams for any 700 or 900 series cars. However, i know for the 200 series cars there was a single difference that required that I switch out the harness. at that, the over drive relay is entirely different. I figured out that you can probably re-wire the existing harness... but as I had the harness, I just switched them out. If you go with the m46, you will also be lacking a 5th gear indicator light unless you get creative--that part is definitely not plug and play. I don't have one. At some point I will splice one in, but it is not going to be very simple.

I dug up this link that was what I based my tranny switch on. he says you CAN just use the existing wiring harness, and he is dealing with a 700 series car. so, check it out. http://www.volvoclub.org.uk/faq/Volv...Conversion.htm
I would not go forward, though, unless you can get some solid wiring diagrams on the car you are switching the tranny from and the car you are switching it to.

 

I've noticed. I have searched high and low for wagon 740 model... I found one and they wanted $19000. So could I just use the transmission from a sedan and make it work?

 

sedans and wagons are identical mechanically and electrically in every way but the tailgate vs trunk and rear lighting.

manuals probably have a different final drive ratio in the differential. so do turbos, making 4 combinations. also manuals have a different length front-half of the drive shaft.


re: that OD relay thing... going by the prints for 1991 and 1992 740/940...

the AW71 automatic and M46 manual both have the OD relay plugged into the same space, middle row, rightmost slot "I". The automatic uses relay 1398154 or 3523804. the manual uses 3523806.

on the automatic, relay pin 8 is hte optional downshift inhibiter (I don't think this was used in US models?), relay pin 2 is ground, relay pin 4 is the button, and relay pin 3 is powered via the ignition switch and fuse 12. relay pin 5 is grounded to turn on the OD disabled light. relay pin 3 goes to the OD solenoid and is powered to enable OD.

on the manual... its almost the same, hahahaha, but the relay works differently. there's a "gearbox is in 5th" switch wired to pin 8 of the relay. the 'its in overdrive' light in the dash (whihc is a different light than on the automatic) is wired between pin 9 of the relay and ground.


so... it looks like you can just drop in the manual relay module in place of the auto relay, and hook everything up correcty at the tranny side and it will just play. add the OD light to your dash (odds are pretty good the bulb is not installed). you may need to add a wire for the gearbox-is-in-5th switch, from the OD relay pin 8, its a blue-black wire to connector A pin 2, then a brown wire to connector C pin 2, then a brown wire to this switch, which goes to ground. these wires might already be in place, as they were used for 'turbo +' systems as an kickdown inhibitor (on the so-equipped automatic, the switch in question was an oil pressure sender on the transmission, which probably doesn't exist on US models). connectors A and C are the same connectors the OD solenoid is wired through (connector C is under/near the console shifter).

 

I saw one other 740 Turbo Wagon manual a few years ago. I regret now stripping everything out of it every day. Okay, maybe not every day. It was an 87 model year white wagon with a tan interior. The only part that lives on today is the grille on the front of my car. My car is an 89 740 Turbo with a manual. Those are the only two turbo manual wagons I've ever seen.

I have heard that the M47 can survive just fine behind a turbo redblock if it's running stock boost levels. The real problem is the oil level in the M47. They put the fill plug low and reduced the amount of oil in the tranny. The 5th gearset suffers in the back add-on section of the transmission. People jack up their cars on the fill plug side and 'overfill' the case to rectify this. It seems to work. Mechanically the M46 and the M47 are the same ratio-wise and in setup. The M47 has a slightly shorter change from 4th to 5th and that section is a little weaker. The electronic overdrive is just stronger. But when you get to the point of pushing its limit, the case of the transmission will start to spread (around 250 HP) first.

740 M46's are aluminum cases, but 240 M46's are cast iron cases. The shifter mount is also done a little differently, but I'm not sure if they just do the same job, but are made different, or if they actually locate the shifter lever in a different location. The best option is getting a 740 donor. The fly wheel may be the trick, but I got one once from a guy on turbobricks, philski o'flood.

My car has a 3.51 rear end, your car should have the 3.73. Non turbo manuals commonly came with a 3.34. I saw a 4.10 listed in my green book somewhere, but they seemed rare.

If you want a lot of overhead for power, people commonly make adapters for T5 transmissions too. R Sport International makes them and so does Yoshifab.

 

This is all very vary fascinating! I should be getting some if not most of the parts I need soon. I'm still on the hunt for a donor car, but all the stuff I need to "restore" the car's current performance (swapping out the spark plugs, new brake and rotors, blower motor, etc, etc). I may start a new thread for the repairs and improvements. And of course, the manual swap. I'll be sure to include tons of pictures and notes on interesting finds.

 

Oh, and I'm pretty set on a m47 manual with a newer flywheel. Mostly because that seems to be the simplest way to do the swap.

As for the turbo, I may wait to take that on till after I've adjusted to the new transmission. Mostly because it seems to be way more involved.

I would like to kill two birds with one stone. I would if I had help, but it's just me on this one.

 

you'll probably find that LH2.4 compatible flywheel on the same car as the M47, as M47's were more common in the later years (LH2.4 is in 1989+ non-turbo and 1990+ turbo cars).

I have no idea what it takes to pull a flywheel off a engine crankshaft.

 

Ah, the flywheel comes of pretty easily. I mean, if you are that deep in. The transmission needs to come off... bit I figured that is a given. But once that is done, there are 8 hex head bolts that you undo. If you can do it with an impact wrench, that makes it easier, as you can (and probably will) spin the engine if you do it by hand. I did mine all by hand, and had to get a screwdriver in where the starting motor would go to hold it still by sticking a standard screwdriver in the teeth where the motor would engauge.



The flywheel has a bunch of holes, but one spot that is missing holes on the edge that you can't see from this picture. The same is try for the flex plate on your automatic. it is crucial that you put those in the same spot. that is what the black mark is about. Also, when you remove the flex plate, there will be a spacer you don't need anymore. But it isn't very hard. If you end up doing it, look up the torque specks--- you really don't want to have to get in there again because of a loose bolt.