Should the boost gauge needle go to the end?

..of the white bar when on full throttle mine only goes about 2/3 the way!
Where is the best place to plumb in a proper boost gauge?

Thanks,

Tom

'95 T5 GLT Horrid-Green w/ even more horrid-black 'R' alloys! euch vulgar!

c'mon don't be shy!

Thomas,

Mine only goes to about the 1 o'clock position (about a third into the white). From listening to the engine I think the wastegate is opening early as I can hear a constant 'sssshhhhhh' type of noise. Not sure if tweaking the wastegate tighter is the only answer to this.

Anyone else had a similar problem?

Adam

'94 850 T5

It depends, stock boost guage isn't really very accurate.

Anywhere into the white is roughly acceptable, if you have a boost guage fitted the car will run anything from 5-9ish psi depending on a number of possible conditions.

If you want to hook up a boost guage there is a vacuum tree near the throttle body in the engine where you connect it. Have a look at www.volvospeed.com for instructions.

The wastegate will be operating almost all the time, otherwise we would be hitting far too many bars of boost :) :)

If you are travelling at a constant 70mph for instance and ease off the throttle you should hear an 2-3 sec loudish hiss from the engine as the wastegate opens.

Also what you are describing (if it occurs under moderate acceleration) just sounds like a normal turbo sound. Sorry if I'm telling you what you already know, but turbos do make a considerable noise (not just the low speed whine you hear when pulling away).

>Anywhere into the white is roughly acceptable, if you have a
>boost guage fitted the car will run anything from 5-9ish psi
>depending on a number of possible conditions.

Does anybody know the _actual_ boost pressure specs for this engine.
Reading the manual it says it will overboost to produce 240hp for 30 seconds. 30 seconds is a rediculously long time to 'overboost' apart from dragging the brakes up a hill I can't even attempt this!
If 225hp is produced a t 9psi of boost then at 5 psi the engine will only produce ~ 185bhp.
Apart from octane and temperature (of which 98ron and UK weather should both be ideal conditions) do you speak of?


>The wastegate will be operating almost all the time,
>otherwise we would be hitting far too many bars of boost :)
>:)
>

Although wastegates exhibit 'creep' they only truly 'open' under virtually full throttle.

>If you are travelling at a constant 70mph for instance and
>ease off the throttle you should hear an 2-3 sec loudish
>hiss from the engine as the wastegate opens.
>

Thats not the wastegate- its recirculating valve 'dump' valve (not an atmo one).



Regards,

Tom

[liuleichan]

>'95 T5 GLT Horrid-Green

Is that the deep metallic green?

>w/ even more horrid-black 'R'
>alloys! euch vulgar!

The black / gunmetal, fairly narrow spoke?

If so, I actually think your car's colour and alloys one of the most tasteful combinations (there's one near where I live, 850 T5R, in dark metallic green, with the grey / black alloys - looks understated, and very classy).

Lei Chan

As I say, your car does not have overboost, you must be reading the manual wrong!

Yes you are totally correct about the recirc valve being the actual device releasing air, but if the wastegate wasnt working there wouldn't be any air to release, but u know what I mean..:)

The car varies a fair bit, gun it at 20mph from low revs and you'll only reach .5bar, kickdown at 30 and you'll hit about 1 bar. 9.5ish psi is roughly standard, but cars come different out of the factory. Don't forget on your older T5s boost is able to be directly controlled by shortening the wastegate rod.

As for conditions I was referring mainly to if you've gone from part throttle into full throttle, or if you floor it just before gearshift the ECU won't always go into full boost. Aside from that obviously a wide array of engine codes will make the ECU lower boost until they are cleared.

I'd describe it as emerald green- its not the rather nice racing green metallic but a vulgar 'double-glazing salesman dun-good' green. Here's a pic of it from autotrader
[http://freespace.virgin.net/thomas.h...vo_850_t5.jpg]

From page 8:7

"B5234T5

Increase power output to 240hp by temporarily raising boost pressure for a maximum of 30 secsonds"

From the "Volvo 850 1995" handbook
Interestingly although registered in feb95 my car seems to have been made in late 93! All plastic components say '93.

Does anybody have an earlier handbook

Thomas do not get confused with the engine codes. They are very confusing at first glance.

The T5 on the end does not mean it is the 'T5' engine!! There are also T3,T4 T6 variants......these are all 'T5 or R' engines, nothing to do with the 'T4 or T6' engines.

Take B5234T5 for instance.

5 stands for no. cylinders.
23 stands for 2.3 litre
4 stands for no. valves per cylinder.
T5 is the particular engine variant and does usually relate to the size of the turbo I believe.

Try catching 'Markas' at www.t5uk.com as he has a '93 850 I think, so he might be able to help with the earlier handbook.