b230fk Upgrades?
 

Hello I am asking for help on a question that everyone has probably already seen a thousand times. I have a 1997 B230FK 940 with an M90L2, it is currently stock apart from a mbc set to 12psi and having the recirculation valve blanked (all done by previous owner). I haven’t had it dyno’d yet so not sure how much power it’s currently putting out.

What components can I upgrade to get the most power, preferably without changing internals or transmission as of yet? (Things such as a cam are doable but I really don’t like the idea of going any deeper because I don’t have anywhere to neatly store lots of parts or access to a garage).

So far what I’ve gathered is that on stock internals and transmission you can push the engine to about 300bhp. This is done by replacing: injectors, cam, fpr, chips, exhaust, turbo and exhaust manifold?

I’ve seen that some people use VXR injectors (440cc I think?) and Holset HX35/40 turbos but apart from that I am pretty unsure about what brand+model of parts I should get.

Also being able to go is great but being able to stop is even better so any advice on replacements for the brakes are welcome.

Don’t worry about budget so much as I have money saved for new parts.

Also if anyone has a power steering pump available for one of these I could use it as the one on the car is on it's way out.

I believe stock internals can go much higher.

For you I'd recoomend either a B230FT wastegate actuator or an aftermarket adjustable actuator. The B230FK actuator is not reliable for producing 12psi.

You should be getting around 200bhp with 12psi.

I would reinstate the dump valve on the turbo, fluttery noises maybe cool but they are not good for the turbo and they don't help power or response in my experience. How have they made it idle without a dump valve? Aftermarket dumpvalve don't add anything.

To be honest I run my 360 with 97 B230FT on track days and havn't progressed any further than that (A cam and wasted spark just). I have been more trying to solve oil spurting on the dump and crank ventilation issues with the higher boost pressure without going open venting, that and braking, fuel starvation on corners etc.

I think you could get maybe 250 on the standard turbo with better injectors and ideally a bigger maf, otherwise go up in size as little as possible. Big turbos just add turbo lag. A better cam is a fairly easy job, A cam is pretty easy to get, VX3 desireable.

At the end of the day its a bit of a fudge as the maf may well be max out and the ECU will cut fuel if you hit a certain voltage on the MAF, although you can chip that, you will lose your immobiliser security (on the RFIC chip key) which is integrated into the fuel ECU software. I think beyond 250 you should really go bespoke ECU. Others maybe happy with the fudge.

Standard brakes are ok for 200bhp, its really track use that you will find the limits. I'm using smaller 22x276mm merc disks on the 360, they manage just. The 940 uses 26x280mm disks, its a heavier car but its really determined by BHP and cycling not weight. Its not stopping power that is the issue, its overheating and cooling on repeated use, then stopping power becomes a problem as does pad and disk life. You can upgrade the pads to Ferodo DS2500, and make sure your fluid is fresh. If you regularily overheat your brakes into fading terratory you need to inspect for cracks and crazing, change if you see anything other than smooth steel. My disks don't last more than 2 yrs for track use, probably yearly change is better depending on how hot they are getting.
Some have upgraded the 940 to 330mm disks from bigger volvos but you need an adaptor, bigger wheels, bias adjuster etc.

It idles ok when stationary but I've found that when on the move, if I put in the clutch and coast from 3-4k rpm, it will idle at around 500rpm and if I brake the car will cut out completely, first thought was that dump valve but not sure how to reintroduce it as I'm not 100% as to where it should be dumping to. Looking at photos I'm pretty sure it should be connected to the lower connection on the inlet manifold. This connection has been repurposed for a boost gauge by the previous owner so i'll just introduce a t joint for that instead if it is the correct place?

Just for clarification - you say the recirculation valve has been blanked by the previous owner. Do you mean the dump valve (aka BOV or Blow Off Valve) or do you mean Exhaust Gas Recirculation (EGR) valve? I believe they were fitted on 98MY cars which i think yours will be.

It will give Tony a bit more of a clue in helping you if you could clarify that! :thumbs_up:

It is definitely the blow off valve and not the egr. :regular_smile:

According to Vadis, EGR was deleted for the '97MY. They relied on a better cat to do the job.

A good place to look is the Turbobricks forum. It is full of good info on tuning rwd Volvos.

I would also reinstate the CBV (compressor bypass valve). It's purpose is to keep the turbo spinning when you lift off during gear changes, allowing the turbo to spool faster on the next acceleration phase. The vacuum line can go to any port on the top of the inlet manifold, downstream of the throttle body. There should be spare ports blanked off. Yoy could fit a nipple to one of those. From memory the tread is 1/8" BSP. Somebody on the forum may have a spare.

First step would be upgrading the turbo to something more suitable. Easy options would be a 16T or 19T turbo. Once the turbo is upgraded then you can consider doing the cam

Yeah if it doesn't dump it will not idle after acceleration (when pressure is built up). It dumps to the atmostphere (out the air filter) by allowing the air to bypass the spinning turbo. It take a good few seconds to clear the pressure from the intercooler and pipework if there is no dump and the throttle is closed. You can usually keep it going with a little gentle reving for 5s or so.

It is called a recirculating dump valve because it is open always during idle because its all after the MAF. Other non-recirculating types open momentarily until the pressure equalises, they dump after the MAF so have to close otherwise air is sucked in via the valve and not measured.

Some people think the recirculation means the pressure is recirculated and used by the engine and maintains the mixture from measured air, however not really what is happening, the ECU does not keep a log of past airflow, it only knows air flow now. When you close the throttle it immediately starts trying to do closed loop operation with the O2 sensor using a weakish mixture, it cannot respond quickly enough to enrichen the muxture so it just dies pretty much immediately. A MAP type system might work better in theory, but the 940 doesn't measure MAP(manifold absolute pressure).

If there is pressure in the system and no demand for power, it just uses the air in the inlet after the turbo and there is no measured air. Also its not really using the MAF, its mostly using the O2 sensor which is not a dynamic measurement. I think the MAF is involved somehow but its different to open loop mode during non-idle.

You just need the diaphragm, spring and the proper cover with the vaccum line nipple. Its connected to any of post throttle manifold nipples I think, some are larger than others, mine is the lower one of the 3.

It might be they have disabled or adjusted the throttle closed sensor too (this can keep the mixture rich), so you need to find out what they have done to achieve this stupid modification.

The first things that needs to be addressed is air metering and fuel. It's well known that you will reach 'fuel cut' with anything more than about 330cfm though whatever turbo is on the engine and the injectors will be at max cycle. Expect 220hp to be the limit here.
Addressing the air metering with a 3" Amm and 440cc injectors with fuel and ignition chips designed for the correct amm linearisation tables and injector constants will enable you to utilise the higher cfm of larger turbos like the 19T. At 18psi my 940 makes 265hp after tweeking the ignition map on a roller.
Cam choice is also a big factor, internet dogma says get a larger cam but you will make more torque with TD04 HL turbos with a T or A cam. The IPD cam will give you a lower but more broad torque curve with more high end hp when used with a 19T if my car is anything to go by.
Then you have the exhaust which should be 2.5" minimum 3" is preferable, and if money is no object the TTV flywheel and 850R clutch kit is amazing.
There is probably more or something I've missed, even people that might disagree but this is just what I have found