Looking to build up a 940 turbo, need advice

[sspiff]

Hi everyone.

I'm looking to start a new project car, and am looking at a 1990 Volvo 940 sedan. It's a factory turbo model that's high mileage but well cared for.

My goal is to make this car into road trip sleeper. I've got a shopping list of requirements, but not sure where to start.

Here's what I want to achieve:

• 380-450hp
• M90 transmission swap
• Good road feel/suspension for spirited mountain drives
• Good brakes for long mountain road descends
• Retain factory A/C
• Retain original look and interior as much as possible

This car will mostly be driven on empty back roads, but see the occasional road trip across the alps. I might take it to a track day occasionally, but importantly, this is not intended to be a track or race car. My wife and children must still feel comfortable and safe in the car. Think of the end result as a GT car with a back seat.

I am aware this will not be cheap. It doesn't have to be. I've always loved Volvos and this will be my third Volvo out of 5 cars I've owned, and am looking for this to be a personalized car I can keep hopefully forever.

Please tell me if you have any pointers, about your experience building up red block Volvos, or if you feel like this is a stupid idea to begin with.

 

[fatcatbestcat]

Okay, couple things;

1. 1991 was the first model year for the 940s. There might be some produced in 1990 but there were no "1990" model year 940s.
2. Unless your wife/kids have a death wish, you could have a lot of fun at about half your power goals. I have a basically bone stock '91 940 Turbo with an M90 and it's quite good fun to drive even at ~180 horsepower. Probably even less. If you go the M90 swap route and intend to take it on the highway, I'd suggest something longer than the stock 3.73 rear gear for cruisability. I would seriously question safety and comfort and driveability on a car with more than double the stock power.

What's your intended budget, and your personal skill level? To hit your power goals with a redblock, you're probably looking at a whole engine build with some specialized parts. Definitely some kind of head porting at a minimum.

 

[sspiff]

Unless your wife/kids have a death wish, you could have a lot of fun at about half your power goals.

I'm not expecting to utilise the car at the limit with them in it obviously.

What's your intended budget, and your personal skill level?

Budget is maybe 10-12k excluding the purchase of the car. My personal skillset is quite limited, but I've done some basic stuff in the past. I did an engine swap in my previous project (from one OEM model to a later OEM one, no fabrication), big brake install, clutch replacement, shock and spring replacement, some electronic gremlin debugging.

I'd be looking to upskill for this project though, and have help from friends who are more experienced at this.

I'm also not intending to do the big engine work up front. My idea is to do a little engine bolt on stuff, suspension and brakes first, and see if I love the car enough to go the whole 9 yards. I understand that the initial engine modifications would need to be replaced again when taking things further.

I was expecting having to replace rods and pistons, and have to have some porting done on the head.

 

[sspiff]

1. 1991 was the first model year for the 940s. There might be some produced in 1990 but there were no "1990" model year 940s.

Apologies, I mistyped. It's a 1991.

 

[Boxtoy940]

I have a NICE UNUSED Plug-N-Play BTI Wasted Spark Kit with CHIPPED 148 Ezk (Ignition Computer) & CHIPPED 967 (Fuel Ecu Computer) for $550 plus the Ride to get to you...Look for me in the 4 Sale Section...

 

[Wilford Brimley]

I'm not expecting to utilise the car at the limit with them in it obviously.




Budget is maybe 10-12k excluding the purchase of the car. My personal skillset is quite limited, but I've done some basic stuff in the past. I did an engine swap in my previous project (from one OEM model to a later OEM one, no fabrication), big brake install, clutch replacement, shock and spring replacement, some electronic gremlin debugging.

I'd be looking to upskill for this project though, and have help from friends who are more experienced at this.

I'm also not intending to do the big engine work up front. My idea is to do a little engine bolt on stuff, suspension and brakes first, and see if I love the car enough to go the whole 9 yards. I understand that the initial engine modifications would need to be replaced again when taking things further.

I was expecting having to replace rods and pistons, and have to have some porting done on the head.

Well getting 400hp for you may not be very easy...

 

[Wilford Brimley]

Well head work, rods, aftermarket fuel management, big turbo, fueling, 16v head swap would be good, you should search

 

[sspiff]

Well head work, rods, aftermarket fuel management, big turbo, fueling, 16v head swap would be good, you should search

I would prefer not to do a 16v swap because they're hard to get (I've only ever seen one available locally).

But I was planning on installing as part of this project:

• Standalone ECU
• Bigger fuel pump, bigger injectors
• Buying some better flowing exhaust manifold + bigger turbo kit for the 8v that's been tested to make at least this amount of power
• Sequential ignition, probably with a coil near plug setup
• Upgraded pistons and conrods

I was hoping there would be more people with something like a tried-and-true formula for this type of stuff I could use as a template to modify.

you should search

I have been searching. Unfortunately, most of the projects with similar amounts of power turn out to be Swedish and I don't speak Swedish.

However, since I'm in Europe, the good thing is that I can get parts from them quickly and quite affordably.

 

[sspiff]

for $550 plus the Ride to get to you...Look for me in the 4 Sale Section...

Sorry, not looking to buy parts at this stage before I have an idea of what I need and even then, I'd prefer to source the parts from this side of the Atlantic, given shipping and import taxes can get pretty ridiculous.

 

[OttoB]

B230, 19T turbo with 940 manifold, A-cam, compression ratio under 9:1, KL intercooler, mild porting. Professional chip Tuning or aftermarket ECU. This will give over 450 Nm and 300 hp and will go on and on.

When dreaming GT Style traveling the max power is not the thing. Wide range of torque makes driving easier and more relax. To keep things more reliable the factory solutions are usually the easiest and most cost effective way.

 

[sspiff]

B230, 19T turbo with 940 manifold, A-cam, compression ratio under 9:1, KL intercooler, mild porting. Professional chip Tuning or aftermarket ECU. This will give over 450 Nm and 300 hp and will go on and on.

When dreaming GT Style traveling the max power is not the thing. Wide range of torque makes driving easier and more relax. To keep things more reliable the factory solutions are usually the easiest and most cost effective way.

Is this reliable on a stock bottom end? If so, is this the limit of what's reliably achievable?

 

[OttoB]

Yes, if it includes a complete rebuild. I would add a H-profile conrods (remanufacturing old rods or new, cost is about the same) and choose Mahle pistons over forged ones on this kind of use.
If swapping to M90 then a later L2 wide ratio model and 3,31:1 would be my option. But I'm low rpm guy.

Low rpm torque is unfortunately a good way to lure knock in to the cylinder. Especially when cruising a long time at the higher load. Everything will heat up. Lower compression ratio makes things easier even you sacrifice some fuel efficiency.

 

[sspiff]

Low rpm torque is unfortunately a good way to lure knock in to the cylinder. Especially when cruising a long time at the higher load. Everything will heat up. Lower compression ratio makes things easier even you sacrifice some fuel efficiency.

While the ECU I was planning to use does not have built in knock control, I was thinking of adding a separate knock warning detector/indicator to make sure the engine is running happily.

If swapping to M90 then a later L2 wide ratio model and 3,31:1 would be my option. But I'm low rpm guy.

Is it necessary to swap the m46 out for a 300hp build? Or is the M90 just more driveable in general?

Yes, if it includes a complete rebuild. I would add a H-profile conrods (remanufacturing old rods or new, cost is about the same) and choose Mahle pistons over forged ones on this kind of use.

Thanks for the tips. I was planning on taking the engine out & checking tolerances on the bearings and the cylinder walls. It's a high mileage engine and it would probably need a rebuild before cranking up the power to be safe.

Everything will heat up.

Are there any common ways to improve the cooling on a redblock? Other than the typical "get a bigger radiator".

 

[sspiff]

Well getting 400hp for you may not be very easy...

If not, then what is a realistic power figure?

 

[fatcatbestcat]

Is it necessary to swap the m46 out for a 300hp build? Or is the M90 just more driveable in general?

Basically none of the factory Volvo manual transmissions will reliably take any amount of horsepower over stock. There's still a lot of unknowns about the M90 in regards to how much torque it can handle, but it seems to be generally accepted that it can survive 300+ horsepower, assuming you have a later transmission or have done the welded stopring mod.

There's tales of people blowing up M46s and M47s at stock power levels... third gear in my 76 horsepower diesel 240 was already broken when I got it.

Thanks for the tips. I was planning on taking the engine out & checking tolerances on the bearings and the cylinder walls. It's a high mileage engine and it would probably need a rebuild before cranking up the power to be safe.

If you're going through the trouble, why not just get a newer, later model redblock? If you're in Europe they were available for more years, and the 1993+ ones have piston squirters to keep wear down and protect what's probably going to be an expensive engine investment.

The topic of 16v conversion has been brought up - you stand to get a lot closer to that 450 hp number with a head that flows even better than most ported 8 valves. There's a lot more steps in building up a 16 valve redblock, but in the end at this power level you're building an interference engine either way. It would be something to consider given your somewhat generous engine budget.

 

[OttoB]

While the ECU I was planning to use does not have built in knock control, I was thinking of adding a separate knock warning detector/indicator to make sure the engine is running happily.


Is it necessary to swap the m46 out for a 300hp build? Or is the M90 just more driveable in general?


Thanks for the tips. I was planning on taking the engine out & checking tolerances on the bearings and the cylinder walls. It's a high mileage engine and it would probably need a rebuild before cranking up the power to be safe.

Are there any common ways to improve the cooling on a redblock? Other than the typical "get a bigger radiator".

M46 limit is around 350 Nm.
Cooling improvement are like more flow through the engine, hi quality water pump, group-A holes in the cylinder head. High pressure cap. Clean block. Separate oil cooler. New radiator. Oil squirters. Heat insulation of exhaust.

I have dreams about an electric water pump and thermostat, controlled with ecu.

 

[sspiff]

There's tales of people blowing up M46s and M47s at stock power levels... third gear in my 76 horsepower diesel 240 was already broken when I got it.

I mean, you can blow up any gear in a manual gearbox with any power, so unless you know how it happened, this is not really an indicator of a poor gearbox, it might be an indicator of a previous owner who was bad at driving a manual

If you're going through the trouble, why not just get a newer, later model redblock?

These cars go for serious money over here. The one I found is a steal for the condition it's in. People are selling these cars with motors which are apart and in the trunk of the car for 3k euro on the used market here, and a clean-ish turbo model with no issues usually goes for at least 8000.

The topic of 16v conversion has been brought up

So, how would I find these 16v heads? I've not seen any for sale, except in one finished project, and I've been watching the local parts market for quite a while. If I look a bit further (neighbouring countries), most of the engines for sale have been ported beyond driveability for far higher power levels (600-650hp) to put into drift cars etc. Not really sure it's wise to build a street car with such big ports?

 

[sspiff]

Basically none of the factory Volvo manual transmissions will reliably take any amount of horsepower over stock.

M46 limit is around 350 Nm.

So what is the recommended path? BMW diesel box? Tremec T5?

 

[Wilford Brimley]

I would prefer not to do a 16v swap because they're hard to get (I've only ever seen one available locally).

But I was planning on installing as part of this project:

• Standalone ECU
• Bigger fuel pump, bigger injectors
• Buying some better flowing exhaust manifold + bigger turbo kit for the 8v that's been tested to make at least this amount of power
• Sequential ignition, probably with a coil near plug setup

I was hoping there would be more people with something like a tried-and-true formula for this type of stuff I could use as a template to modify.

I have been searching. Unfortunately, most of the projects with similar amounts of power turn out to be Swedish and I don't speak Swedish.

However, since I'm in Europe, the good thing is that I can get parts from them quickly and quite affordably.

There's

I mean, you can blow up any gear in a manual gearbox with any power, so unless you know how it happened, this is not really an indicator of a poor gearbox, it might be an indicator of a previous owner who was bad at driving a manual

These cars go for serious money over here. The one I found is a steal for the condition it's in. People are selling these cars with motors which are apart and in the trunk of the car for 3k euro on the used market here, and a clean-ish turbo model with no issues usually goes for at least 8000.

So, how would I find these 16v heads? I've not seen any for sale, except in one finished project, and I've been watching the local parts market for quite a while. If I look a bit further (neighbouring countries), most of the engines for sale have been ported beyond driveability for far higher power levels (600-650hp) to put into drift cars etc. Not really sure it's wise to build a street car with such big ports?

For the 16v you can put a wanted ad out or watch for sale, they come up sometimes, will probably run you 700$ to 1000$

 

[DaleGribble]

User @shoestring has a wicked 940 build. Ask him for advice. I believe he makes a fair bit over 300hp with factory internals, an rsi cam (don't quote me on that) larger injectors and a 19t turbo. Intercooler as well