Forge actuator spring advice please?

[officerbrooks]

As before I have a yellow spring (which may still be too strong) if you'd like to try it.

Thanks I shall try the green first as I think earlier advice was to use the weakest I can get away with. Having got a shiny new Forge actuator I need to spring it as close to Volvo original as I can in order to use it. I believe you're right, RICA maps to suit mostly standard parts and I'm maybe expecting too much so will I have to go to a 19T?

[p fandango]

Edit: In JT's dyno plots it doesn't hold anywhere near 1.2 bar at 6500 rpm so I wonder if we are looking at a rock solid 1 bar?

as always said, a dyno will never be able to recreate the air conditions of a road so wouldn't expect the boost curve to be the same as on the road. I'm sure he checked the calibration of his gauge against against there readings

[jardon]

Ok. My previous experience tells me its unlikely though. Redbricks car made 60bhp more and didn't hold that much boost on a 19t'd 850. Ditto for any td04 I've seen so jt's would be the first.

[p fandango]

Ok. My previous experience tells me its unlikely though. Redbricks car made 60bhp more and didn't hold that much boost on a 19t'd 850. Ditto for any td04 I've seen so jt's would be the first.

no offence, but "your experience" doesn't mean any think inless you've used the same mods as JT. Was Redbricks car MTE mapped as well?

[jardon]

no offence, but "your experience" doesn't mean any think inless you've used the same mods as JT. Was Redbricks car MTE mapped as well?

Apologies - we are arguing about 0.1 bar! My broader point is that these are peaky turbos if mapped for highish boost.

Edit - Andys car has a T5D5 community map using a 17psi actuator - fitted because they were losing boost with a 13 psi spring up top.

[jardon]

Much as I hate to admit being wrong here are some things to consider with regard to boost:

1. TCV's leak a bit so for a given set up an MBC will hold more boost. I don't know what JT runs but my car is mapped for 1.4 bar and will drop a bit compared to an MBC set at 1.4 bar.

2. You can get a shed load of boost but hopeless performance with incorrectly set cam timing.

3. My claim about ME7 engines consuming more air is flawed - they do but in such a way as to spin the turbine faster and make more boost.

4. A stock actuator set very tight will not hold more than 1.1 bar at 6000 - even with hose to the compressor housing detached - it will blow open and if you want to maximize what a 19t has to offer then fit a forge or similar.

5. 1.3 bar at 6500 is possible on a 19t'd 850 with stock head but that likely points to better flowing exhaust valves than inlet and not necessarily more power.

6. There are several reasons an equivalent ME7 engine makes more power than an 850 - I was under the impression it was just vvt and better flowing head but there are other factors including lighter crank and valve springs and bigger throttle.

I live and learn. Hope this helps and sorry for being stubborn.

[p fandango]

Much as I hate to admit being wrong here are some things to consider with regard to boost:

1. TCV's leak a bit so for a given set up an MBC will hold more boost. I don't know what JT runs but my car is mapped for 1.4 bar and will drop a bit compared to an MBC set at 1.4 bar.

2. You can get a shed load of boost but hopeless performance with incorrectly set cam timing.

3. My claim about ME7 engines consuming more air is flawed - they do but in such a way as to spin the turbine faster and make more boost.

4. A stock actuator set very tight will not hold more than 1.1 bar at 6000 - even with hose to the compressor housing detached - it will blow open and if you want to maximize what a 19t has to offer then fit a forge or similar.

5. 1.3 bar at 6500 is possible on a 19t'd 850 with stock head but that likely points to better flowing exhaust valves than inlet and not necessarily more power.

6. There are several reasons an equivalent ME7 engine makes more power than an 850 - I was under the impression it was just vvt and better flowing head but there are other factors including lighter crank and valve springs and bigger throttle.

I live and learn. Hope this helps and sorry for being stubborn.

some interesting stuff there that does make sense, JT's running a MBC & the lightweight flywheel must be helping alot. He was still running the standard actuator in the vid tho, but lets not start on all that again lol

[jardon]

For interests sake I just got 2 old TCV/BCS out of the garage. There is flow in this off-car state between the compressor and actuator ends but no flow through the intake end - because I guess in the de-energised state Volvo want the TCV to default to least boost. I connected the intake end to my mityvac and pressurised each in turn - the oldest one held 10 psi while the newer (not brand new) held 20 psi. I'm not sure what this tells me but something happens with age. I'm not sure if the valve is a pulsed pintle diverting all air to the actuator at 0% duty and all to the intake at 100% duty OR just an electronic bleed valve which is open continuously at 100% duty - this latter description is going to allow the actuator to see some boost pressure which is perhaps why they don't give the same maximum boost at high rpm as an MBC. Any ideas?

[jardon]

Not to be outdone and feeling suitably foolish in my claims I bought a 0.8mm boost restrictor "pill" from Owens and inserted it pre-BCS. The inlet to the bcs is ~2mm in diameter. The theory is less air pressure/volume gets to the bcs from the compressor housing so the bcs is not bleeding as much to the actuator. The upside of this is that I now hold 1.31 bar to 6900 rpm in 4th! There is a small spike in the 4000's to just under 1.5 bar which may be considered a gain or a problem depending on your point of view. This was datalogging with Softloader - AFR 11.3 at full boost, 32 degrees advance at 6900 rpm and iats never got above 19C (ambient 9C). This is an extra 0.2 bar at the redline and it feels amazing. Thanks for helping me prove myself wrong - it was totally worth it! My experience did in fact count for nothing - I live and learn.

[officerbrooks]

So a Forge green spring fitted which still felt stronger than the old Volvo original. I gave the ecu time to accept it and found 1.4 bar initial boost or rather a spike then 1.2 bar and 0.9 from 4500rpm. I changed the BCS to an IPD unit and had crazy low rpm boost but again 0.9 from 4500rpm. Car felt like a high powered diesel so all old original parts now back on and 1 bar at 5000rpm.
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Has anyone fitted a Kalmar Union "Drop in intercooler" is it that straightforward and worthwhile?

[Loadsamiles]

There's no point whatsoever in comparing ME7 with previous systems, they just don't behave in the same way at all. There can be many many reasons why an ME7 will pull boost throttle and timing, it can even change with the weather.

As far as the BCS (TCV) is concerned I have found that (depending on use) as little as 30,000 to 50,000 miles of use is sufficient for it to degrade in performance, the air it uses is corrosive if you are using the stock crank case ventilation return. The ME7 ECU can have it cycling very frequently. What you think would just be an open state can actually be a very modulated cycle of states.

For your turbo to really be fully "on" the car needs to have all parameters correct, just one out of limits will cause truncated boost. If your intake temp or fuelling is anywhere near an unsatisfactory value the ECU will simply not allow a "full power" state to occur, boost, timing and throttle can all be limited.

I did a huge amount of data logging with VADIS / VCT2000, both on the dyno and the road.

It is certainly worth checking that the TCV is 100% functional. it may well be able to open/close a weak actuator if it is slightly leaking, but a stronger spring may well be too much to push against if the TCV is leaking.