850R complete engine rebuild + some questions

[Clemens]

One more thing: whites or blues are good for 300 hp at least, but with a goal of 350 you might wann
a think about greens. Lspeed in Germany has them for a reasonable price.
When buying colored injectors, make sure to buy with the parts number (fcp or ipd list them nicely) because there are similarly colored but wrong injectors out there (whites with a different specs were used on 5 cylinder Audis for example)

[Jaydiesel]

If you want to get lost in one of the craziest 850 builds.
google. THE PERIL - 1995 Volvo 854 T5-R

The work this gentleman did to a 850 is just amazing.

[gofra]

Thanks @Clemens - will pay attention!
Question - are we talking about whp or crank power? 300 whp is completely enough for me.

Oh, I'm a sucker for good build threads - especially when it comes to a 850 - thank you @Jaydiesel

[Clemens]

I think these numbers Volvo people talk about are usually whp because alot of the engines never leave the car and just receive bolt on parts and a tune to increase the performance.

[Goupil]

Vast has a power goals page that can give you an idea of what kind of power to expect
https://vasttuning.com/sample-setups/

Honestly if you're going for 300whp I wouldn't bother with a standalone ECU, the M4.4 will do just fine. I'd go with green injectors (as long as you're using gasoline and not E85), they arent much more expensive than blue/whites. I paid under 200€ for mine, brand new Bosch ones.

Stock fuel pump would probably be fine, but they're easy to replace and you never know when the 25yo pump will give up. I run an AEM 340LPH in my car, DW are also a popular drop in. 150€ upgrade for peace of mind.

An healthy M56 will take that kind of power without any issues. The stock 850R clutch can take about 450Nm of torque from what I can remember

[Clemens]

Vast has a power goals page that can give you an idea of what kind of power to expect
https://vasttuning.com/sample-setups/

Honestly if you're going for 300whp I wouldn't bother with a standalone ECU, the M4.4 will do just fine. I'd go with green injectors (as long as you're using gasoline and not E85), they arent much more expensive than blue/whites. I paid under 200€ for mine, brand new Bosch ones.

Stock fuel pump would probably be fine, but they're easy to replace and you never know when the 25yo pump will give up. I run an AEM 340LPH in my car, DW are also a popular drop in. 150€ upgrade for peace of mind.

An healthy M56 will take that kind of power without any issues. The stock 850R clutch can take about 450Nm of torque from what I can remember

yes, 440 to 450 Nm should be correct for the R clutch.
Mind sharing where you fot greens that cheap?

[Goupil]

Vast has a power goals page that can give you an idea of what kind of power to expect
https://vasttuning.com/sample-setups/

Honestly if you're going for 300whp I wouldn't bother with a standalone ECU, the M4.4 will do just fine. I'd go with green injectors (as long as you're using gasoline and not E85), they arent much more expensive than blue/whites. I paid under 200€ for mine, brand new Bosch ones.

Stock fuel pump would probably be fine, but they're easy to replace and you never know when the 25yo pump will give up. I run an AEM 340LPH in my car, DW are also a popular drop in. 150€ upgrade for peace of mind.

An healthy M56 will take that kind of power without any issues. The stock 850R clutch can take about 450Nm of torque from what I can remember

yes, 440 to 450 Nm should be correct for the R clutch.
Mind sharing where you fot greens that cheap?

That was in 2020 so might not be the best price around anymore (bought 4 from another seller for my 940 last year, was 140€, they're now listed at 230 )
https://www.ebay.com/itm/111579190035
The one I got werent the Volvo specific version so I had to remove the retaining plate under the fuel rail, but no issues otherwise.

[gofra]

Vast has a power goals page that can give you an idea of what kind of power to expect
https://vasttuning.com/sample-setups/

Honestly if you're going for 300whp I wouldn't bother with a standalone ECU, the M4.4 will do just fine. I'd go with green injectors (as long as you're using gasoline and not E85), they arent much more expensive than blue/whites. I paid under 200€ for mine, brand new Bosch ones.

Stock fuel pump would probably be fine, but they're easy to replace and you never know when the 25yo pump will give up. I run an AEM 340LPH in my car, DW are also a popular drop in. 150€ upgrade for peace of mind.

An healthy M56 will take that kind of power without any issues. The stock 850R clutch can take about 450Nm of torque from what I can remember

Thank you Goupil!

The reason I'm thinking about a standalone unit has more to do with actual control and precision. Having read a bit about the Motronics, I'm a bit scared of the "ON/OFF" boost management nature and really like to set up the boost to come gradually + I'd like the transitions between fuel & timing maps to be as smooth as possible. I do admit, I'm a complete tuning noob and actually have no idea what can be done with M 4.x units. I'd also like to use a wideband O2 sensor, maybe even EGT. Another reason is the ability to do real-time tuning. Re-flashing takes a lot longer + I have very limited options where I live and it's very likely I'll be forced to have an email conversation with an expert. As you can see, I'm prepared to invest a bit more for the peace at mind

Car currently uses white injectors but I might do an upgrade here, yeah. Especially since there is a big possibility they're still stock and way past their lifespan. Fuel pump shouldn't be an issue, true.

What worries me a little is the clutch - based on the link you sent, 300-ish whp would result in 50 Nm above the stock clutch max so I should take that into consideration. Good tuning (no sudden low RPM boost hits) might take some stress off but, again, I'd like to be safe.

Thank you for your feedback!

[Clemens]

There are other clutch options with Sachs clutches that require modificatuons of the flywheel, I'll try to find the link I received a while back.
Alot of these high torque setupts are said to be no fun for a daily driver. As far as I understand (and that's why I chose a R clutch) the R clutch is as good as it gets for daily use unless you like the racecar feel in stop and go traffic.
If you go with a dual clutch setup, stay away from metal metal (sintered) discs, go metal organic. 2 sintered discs are horrible off the racetrack from my experience.

[gofra]

There are other clutch options with Sachs clutches that require modificatuons of the flywheel, I'll try to find the link I received a while back.
Alot of these high torque setupts are said to be no fun for a daily driver. As far as I understand (and that's why I chose a R clutch) the R clutch is as good as it gets for daily use unless you like the racecar feel in stop and go traffic.
If you go with a dual clutch setup, stay away from metal metal (sintered) discs, go metal organic. 2 sintered discs are horrible off the racetrack from my experience.

Thank you Clemens! I'm leaning towards keeping the clutch stock anyhow and probably use torque limiter maps. Out of curiosity - there are no direct replacement options for clutch - without mods?