Just 10 more horses

[rippedoffagain]

Lets say I wanted to squeeze maybe just 10 more bhp out of a 940 auto with the B230FK (LPT) engine, but I wanted to do it cheaply, simply, and without harm to the engine, what would my options be?

I've learned that there is a 'compressor bypass valve' on the turbo, keeping the turbo pressure down to something like 3.5 psi. Is there potential for slight tweakage there?

I want to keep the car as original as possible, and I don't want to kill it

[smithy]

Originally Posted by rippedoffagain

Lets say I wanted to squeeze maybe just 10 more bhp out of a 940 auto with the B230FK (LPT) engine, but I wanted to do it cheaply, simply, and without harm to the engine, what would my options be?

I've learned that there is a 'compressor bypass valve' on the turbo, keeping the turbo pressure down to something like 3.5 psi. Is there potential for slight tweakage there?

I want to keep the car as original as possible, and I don't want to kill it

Put an mbc on it and turn her up and don't worry about the engine or auto box they have been known to run over 350bhp

[volvoz2000]

It is an auto Smithy...... i didnt think it was wise to go much above 200bhp? IF you buy a grainger type MBC, NOT a bleed valve then you can put this in the pipe between the compressor housing and actuator....job done. (start with it wound out all the way and turn it in until you are happy with the improvement)

[rippedoffagain]

Sorry, but what's an 'MBC'?

from what you're both saying, it sounds like a good simple option.

[red baron]

manual boost controller, the likes of HKS etc make electronic versions using a 3 way solenoid to control boost wheras a simple manual version made from plumbing fittings works just as well.

HKS versions cost circa £150 + or the simple version usually costs around £10

[wooble]

For safety's sake I would give strong thought to teaming the manual boost controller with an accurate boost gauge- the temptation to turn it up juuust a little more can be overwhelming, and if you know your boost limits, you're much less likely to accidentally make your engine go boom.

[Steve940estate]

Originally Posted by volvoz2000;1394640I

t is an auto Smithy...... i didnt think it was wise to go much above 200bhp? IF you buy a grainger type MBC, NOT a bleed valve then you can put this in the pipe between the compressor housing and actuator....job done. (start with it wound out all the way and turn it in until you are happy with the improvement)

I'm interested to know why you wouldn't recomment using a bleed valve ?

I've read this in a lot of places but nobody ever gives a reason. I didn't like how it made the car drive although you can set up both to work in a similar way.

If you want to increase the boost to HPT levels the easiest and most discreet way would be to fit a higher pressure wastegate actuator from another car.

[Steve940estate]

Just to add that the compressor bypass valve and wastegate actuator are different things. The wastegate actuator controls the maximum boost by limiting the exhaust gas powering the turbo. The bypass valve is there to allow the turbo to keep spinning when the throttle is closed.

I'm interested in how various methods of boost control work. I started a thread the other day about what I am trying at the moment but a lot of people use other methods. The best and most reliable method of controlling the boost pressure is by fitting a new actautor. They aren't cheap and are only available in limited different pressures so trying a few different ones isn't really an option.

There isn't a huge amount of info about way one particular method is better than another other then whats popular at the time.

[smithy]

Originally Posted by volvoz2000

It is an auto Smithy...... i didnt think it was wise to go much above 200bhp? IF you buy a grainger type MBC, NOT a bleed valve then you can put this in the pipe between the compressor housing and actuator....job done. (start with it wound out all the way and turn it in until you are happy with the improvement)

In he USA most are autos and they don't have problems at all

[volvoz2000]

OK, here goes:

1) the LPT actuators are so soft that no amount of bleeding will help as the exhaust pressure blows the wastegate open
2) You can put washers between the HPT actuator and the compressor housing along with a bleed valve to achieve 12-14psi
3) use http://www.ebay.co.uk/itm/TURBO-MANU...item33590834bd as these dont bleed pressure off but serve to force the wastegate to stay shut and work suprisingly well on the LPT actuator
4) good point smithy, but always been a little vervous of turning up the wicks on the autos similar to Volvo not wanting to supply turbo+ on an auto.
5) I can supply recon 16t/19t/19t hybrid with modded downpipes and suitable actuator brackets to take any garret actuator you fancy from 10psi right up to the infamous -31 that will static boost or bleed all the way to 30psi no problem
6) I can also supply you machined 16t flange and the actuator bracket to suit 16ts etc... but you will have to drill and tap the name plate on the compressor housing


In short, if you want to do the minimum possible then follow the link. If you want to be a little more scientific and not have a bleed valve then fit an HPT actuator spaced with a couple of washers (stealth), and if you want to go balls out then buy a new turbo/dowpipe with -31 (you need to consider other supporting mods such as chips to warrant going away from the 13C as your car will fuel cut somewhere around the 18psi mark). Beauty of the garret actuators is that they are all adjustable by means of changing the length of the shaft so negating the need for a bleed valve unless you like the ease of one