B5234T3 Max safe boost ?

[iancho]

^^^^^ was going to ask this myself :-)

Lol... i think they could be on about not thrashing it from a standing start and waiting until the rev counter hits 3 or 4k and then booting it.

[shepbomb]

Rumour has it that if you boot it before you get to 3k you run the risk of bending a rod, although I think this is of more concern to the lads who have done quite a bit of engine modding, I'm sure somebody more knowledgeable will be along shortly

[lance]

It used to happen when people ran a 15 g map with a 19t irrc, I rarely boot mine above 3 k on the road this time of year as in top gear it's 90 mph and in the lower gears it wheel spins in 3 rd comfortably but my torque is diesel like from
1500 rpm and just booting to 3k leaves most cars standing.

[M-R-P]

My boost creeps - up to 5-7psi before 3k rpm any way so I'm not too fussed.
If I floor 2nd at 3krpm (30+mph) the turbo spools up real fast and stays at 16psi till I change gear at about 5.5krpm.
Good for overtaking

3rd gear is a bit different - I'll get 16psi for a while, then it tails-off to 10psi. If done properly it's still good for spinning the wheels from 50mph.

4th for some reason, holds the boost for longer - I use that for upsetting M-Sport drivers on the motorway.

[jardon]

Since fitting the boost restrictor in the TCV line I have less control of boost once over 4500 rpm - it over boosts to 1.7 bar (24.5 psi) and then settles at 1.5 bar (21.5 psi) before dropping off to ~ 1.35 bar (19.5 psi) at the limiter.

It has done this quite a few times and nothing has broken yet. This is a stock 2001 ME7 T5 block. I don't know what I'd have to do to break it to be honest as so far it seems to take anything I try. It's never seen more than 1.3 bar below 3000 rpm even with 100% ETM, 100% TCV duty and my 1.2 bar actuator - perhaps this has been what saves it but as so few folk with ME7 cars have bent rods it's difficult to know what the limits are.

[partsforvolvos.com]

plod arent allowed to modify cars- they have to drive home office tested and approved hologlomated models, as if they are involved in a fatal crash, then it could be a relevent factor.

[M-R-P]

plod arent allowed to modify cars- they have to drive home office tested and approved hologlomated models, as if they are involved in a fatal crash, then it could be a relevent factor.

There are exceptions - You should see the Special unit's red V70 that goes screaming around dorset, there's no way mine would keep up with that.

[stribo]

You should set the boost around 22psi, then see whose liners crack first.

[M-R-P]

Since fitting the boost restrictor in the TCV line I have less control of boost once over 4500 rpm - it over boosts to 1.7 bar (24.5 psi) and then settles at 1.5 bar (21.5 psi) before dropping off to ~ 1.35 bar (19.5 psi) at the limiter.

It has done this quite a few times and nothing has broken yet. This is a stock 2001 ME7 T5 block. I don't know what I'd have to do to break it to be honest as so far it seems to take anything I try. It's never seen more than 1.3 bar below 3000 rpm even with 100% ETM, 100% TCV duty and my 1.2 bar actuator - perhaps this has been what saves it but as so few folk with ME7 cars have bent rods it's difficult to know what the limits are.

What size was the restrictor? I've used a tap and partially closed it in an effort to restrict it but had no joy.

[M-R-P]

You should set the boost around 22psi, then see whose liners crack first.

Won't be mine but the turbo would probably melt

[Wobbly Dave]

Stop fannying around & get a remap LOL.

[M-R-P]

Given the money Dave I would but finances just won't allow that kind of frivolity

[Wobbly Dave]

If only posts were pounds - you'd be rich by now.

[jardon]

What size was the restrictor? I've used a tap and partially closed it in an effort to restrict it but had no joy.

0.8mm and it sits in the line between the compressor housing and TCV. I think a larger one would offer better boost control but I haven't got around to trying. I'm happy with it as is. I never limit my right foot below 3000 rpm - I did initially when I fitted the Forge actuator but no matter what I do it seems "safe" at lower rpms. I have positive boost from 2000 rpm (possiblly lower as I haven't checked for a while) and it pulls hard from ~2700 rpm. I lose traction in higher gears at around 4500-5000 rpm so thats where peak torque is. The Forge actuator made a huge difference to boost holding after 5000 rpm and each increase in spring stiffness has helped ie: stock actuators are not up to the task if you want to run a stock turbo at it's ragged edge. I didn't think the boost restrictor would make much difference but my knowledge of TCV's was clearly flawed - the wastegate was blowing open even with a 1.2 bar spring!! . My turbine wheel is clipped which may explain why it doesn't boost high below 3000 rpm at WOT. Your 16t might boost harder at below 3000 rpm but as you have a stock exhaust and intercooler I could be wrong.

[oblark]

plod arent allowed to modify cars- they have to drive home office tested and approved hologlomated models, as if they are involved in a fatal crash, then it could be a relevent factor.

Plod cars are remapped and have uprated suspension and brakes.

[M-R-P]

Plod cars are remapped and have uprated suspension and brakes.

The older ones were mate. The P2 stuff leaves the Special Vehicles Garage in gothenburg (the only volvos made in Sweden these days) with reinforced chassis, bigger arb, bigger droplinks, stronger shock tops and nivomats. Anything done to the engine is done by the force that owns it.

BUT... in 2003, only 7 V70 T5 SE cars were registered new in the UK. at least 5 of them were plod cars, possibly the rest but I haven't found them yet. 3 were registered to the same force (GMP) so there's the possibility of a small group of tweaked traffic cars. This is merely speculation as I haven't been in or fiddled with any other ex plod cars to make a comparison.

[V70 Graham]

..... I haven't been in or fiddled with any other ex plod cars to make a comparison.

I really must take my time reading posts, thought you said you had been fiddled with by plod.....now then now then

[mikey32shaw]

Have to ask another daft question sorry :-/ what's a nivomat?

[oblark]

The older ones were mate. The P2 stuff leaves the Special Vehicles Garage in gothenburg (the only volvos made in Sweden these days) with reinforced chassis, bigger arb, bigger droplinks, stronger shock tops and nivomats. Anything done to the engine is done by the force that owns it.

The gothenberg factory still makes the V70, XC70, S60 and the XC90, I saw these cars being made

All the LARGE volvos where made in gothenberg EG, P2 V70, 850, 740 and the 240 all the smaller volvos are made eslewhere.

[Wobbly Dave]

A nivomat is a brand of self leveling shock absorbers. Personally I thought it was more suited to the name of a laundrette or washing machine.

http://www.cadillacfaq.com/faq/answers/nivomat.html