B5234T3 Max safe boost ?

[M-R-P]

So a question for those more knowledgeable than myself...

What would be considered the maximum safe boost level on my engine before things go crunch.

3rd generation 2.3 T5 with 16t and 197k miles on it.

I've been fiddling with MBC and TCV combinations and saw an unexpectedly large number on the boost gauge, at which point, I let off the loud pedal.

[oblark]

I would say about 15 psi :)

[t5 pete]

All depends on how the boost comes in aswell what boost are you running at the min i bent a rod with 18/19psi

[T5frankie]

17psi

[M-R-P]

All depends on how the boost comes in aswell what boost are you running at the min i bent a rod with 18/19psi

I've been running 16psi for a while now, which droppes off after a while. I've been trying to keep the boost on longer so I've been fiddling about with a new bcs and the mbc in - line. I won't just floor it as I'm well aware of the 3k rule, so I waited till 30mph in 2nd and gave it a bootful, the boost came straight on and hit about 18psi before I backed off. It didn't look like it had finished either.
By hell did it move!
But obviously, I've not achieved anything tho.

[T5frankie]

i never booted mine till after 4k but still bent rods

[claymore]

I was boosting mine to 22psi and still couldn't bend the rods :)

[volvokid]

If your cars mapped correctly you shouldnt have to give a hoot when you boot it.

[M-R-P]

i never booted mine till after 4k but still bent rods

You're just to butch with the go pedal Frankie ;)

I was boosting mine to 22psi and still couldn't bend the rods :)

With a 16t? :yikes:

If your cars mapped correctly you shouldnt have to give a hoot when you boot it.

Mapped? the car hasn't tried to protect itself yet so maybe plod did something...?

[oblark]

Mapped? the car hasn't tried to protect itself yet so maybe plod did something...?

You can bet your cars been mapped :)

[claymore]

With a 16t? :yikes:




No, with a gt28

[M-R-P]

You can bet your cars been mapped :)

Here's the thing - plod don't normally map the T5s as they consider them fast enough but so many things point to it not being standard. You've been in it mate so you'd have a better idea than me. The only other T5 I've been in is Graham's and that's been mapped but because the gearing is different, it was hard for me to make a comparison (if anything, his 3rd felt a bit slower but again - gearing)

I've been in Wayne's V70 but there was no "fast" driving going on.

[T5frankie]

I was boosting mine to 22psi and still couldn't bend the rods :)

and still only 14.7 lol

[M-R-P]

No, with a gt28

My little 16t went from negative boost to 18psi in a second, maybe 2. Poor little thing has done 197230 miles :(

Gonna back it all off tomorrow and see if I've done something silly like connect the MBC backwards lol.

[oblark]

Here's the thing - plod don't normally map the T5s as they consider them fast enough but so many things point to it not being standard. You've been in it mate so you'd have a better idea than me. The only other T5 I've been in is Graham's and that's been mapped but because the gearing is different, it was hard for me to make a comparison (if anything, his 3rd felt a bit slower but again - gearing)

I've been in Wayne's V70 but there was no "fast" driving going on.

I think it`s had mild map :) but you will find out more when you put it on the dyno :)

[LiamT4]

Here's the thing - plod don't normally map the T5s as they consider them fast enough but so many things point to it not being standard. You've been in it mate so you'd have a better idea than me. The only other T5 I've been in is Graham's and that's been mapped but because the gearing is different, it was hard for me to make a comparison (if anything, his 3rd felt a bit slower but again - gearing)

I've been in Wayne's V70 but there was no "fast" driving going on.

Grow a pair and get it on the 1/4mile, then you'll know how quick it really is ;-)

[M-R-P]

Grow a pair? I did mate and then my wife quite publically cut them off lol ;)

[M-R-P]

Well to conclude, I wound the MBC back a bit and she's back to normal - sort of.

She boosts to 16psi, as before and still drops down after a while BUT it takes longer to drop down to 10psi spools up faster, so there's a nice, new lump of torque to play with. Much to the utter annoyance of a noisy Type-R driver last night.

It's weird how the new BCS caused so much boost when the MBC was still set at the same level, especially when, without the MBC, the BCS only gives 9psi which is what the original one produced.

Any-hoo, it's all working now - to a fashion.

I need a remap!

:(

[iancho]

I've been running 16psi for a while now, which droppes off after a while. I've been trying to keep the boost on longer so I've been fiddling about with a new bcs and the mbc in - line. I won't just floor it as I'm well aware of the 3k rule, so I waited till 30mph in 2nd and gave it a bootful, the boost came straight on and hit about 18psi before I backed off. It didn't look like it had finished either.
By hell did it move!
But obviously, I've not achieved anything tho.

Sorry to hijack Martin but what is this 3k rule? and why is Frankie waiting until 4k?

[mikey32shaw]

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

[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. :smile:

[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. :P

[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. :P

Won't be mine but the turbo would probably melt :D

[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

[M-R-P]

Most 850s and P2 cars were made in Belgium. If anybody fancies going and having a look at their vin plates, and reporting back...?
I dunno about the P3 stuff, but if you've seen them making them (which I know you have) then that's where at least most of Europe's big swedes come from.
good thing too imo.

[oblark]

Most 850s and P2 cars were made in Belgium.

No the 850`s where made in gothenberg. The VIN plates are made in Belguim.

On the wall in the factory are car shells cut in half from front to back that where made they and one of the cars is a red 850 saloon :)

[M-R-P]

I really don't think Belgium and Gothenburg are world centres of vin plate production mate ;)

[oblark]

They got to be made somwhere :)

[jardon]

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.


OK.. so I tested my statement and it's §§§§§§§§. I held it at WOT from 2000 rpm in 4th and at 3000 rpm it spiked to the almost the end of my 2 bar gauge. I say spike because it didn't stay there long - just bounced up and back down. On that basis I can't recommend what I've been up to but nothings knocking yet. I must have unconsciously been holding back below 3000 rpm because I haven't seen that before. There is positive boost from 1400 rpm (0.1 bar) and at 2000 rpm it makes 0.4 bar - at no point does the gauge drop below zero, even down to 1000 rpm. There is a cross-over around 2001 where the ME7 rods became more robust - I haven't looked into what I have. I think one could say for certain that if this was a P1 engine I would melted and bent every component over the last 12 months. I know the mapping is a faff but ME7 is pretty good from where I'm sitting.

[M-R-P]

That's a good point - I've not heard many P2 owners saying they've bent a rod but then, most go straight to a Remap without messing with the vac system. I'm not as worried about the rods as I am about the sheer age/mileage of the engine. Last time I got my hands on the turbo, there was no movement in the shaft but that was before I upped the boost and the wastegate paddle has an internal rattle when I wiggle the arm. Maybe I should just stop messin with it but the power is quite addictive lol.

[t5 pete]

Myne bent its rod before 4k i think around 3k with 18/19psi but i can get full boost way before 3k it must be the ebc that makes th eboost come in very fast as it didnt used to when i had a map alone on it

[jardon]

Been doing some thinking on how to reduce the tendency to overboost while retaining the boost up top. All the restrictor does is reduce the volume of air reaching the actuator - I think volume of air flow through a pipe is proportional to cross sectional area but I'm happy to be corrected on this if I've missed something. The BCS inlet (metal end) has a 2.7mm orifice. Some cross-sectional areas (in square mm) with orifice diameter:

0.8mm - 0.50 (my boost restrictor)
1.0mm - 0.79
1.5mm - 1.77
1.6mm - 2.01
1.7mm - 2.27
1.8mm - 2.55
1.9mm - 2.84
2.5mm - 4.91
2.7mm - 5.73 (my BCS)

So I think flow is being reduced by a factor of 5.73/0.50=11.5!! The actuator is seeing over 10x less volume of air than without the restrictor!! Over a long enough period the air pressure after the restrictor will reach that before it but if the actuator is to retain timely control as boost rises rapidly then the current situation is failing. I use the word control loosely as this is a 1.2 bar actuator.

Bear in mind there was no nasty boost spike with no restrictor so I reckon there is room for compromise. If I wanted to halve the amount of air reaching the actuator compared to just a BCS I would need a cross sectional area of ~2.87 which a 1.9 mm diameter restrictor would give. There are flaws in the maths here because the BCS leaking at 100% duty may not happen below a certain pressure threshold but assuming it does (it doesn't) then the relative flow calculations above are ball-park sensible. TBH I just wanted to know how much I had reduced flow and 11x sounds excessive. I am going to drill the one I have to 1.9mm or slightly less and see what happens.

EDIT - MIG welding tips are brass, cheap and come in appropriate orifice sizes.

[M-R-P]

Funny you should mention MIG tips - I run the stores for a big steel fabrication firm. Problem is, the smallest tips we use are 1.2mm. We also have 1.6, 2 and 2.2mm. I might have a play with the smaller ones next week ;)

[jardon]

1.2mm orifice gives 1.13 square mm cross section. This reduces volume of flow by 5 times. I'd try that (cautiously).

[jardon]

Quick update - I fitted a yellow (9 psi) spring in my actuator and ran it with the 0.8mm restrictor. It still spikes on spool up but would not hold anywhere near as much boost as with the red (17.5 psi) spring without the restrictor. I take from this that it is mostly increased actuator stiffness that enables my 19t to hold boost at the top end and mid range. The boost restrictor has an influence as it spools faster with it in situ when using the yellow spring even if it won't hold more boost. By using the restrictor I squeeze a little more boost at the top end out of the red spring but in light of the spikiness on spool I am going to trial a larger restrictor. I've said it several times but don't underestimate the performance gain of using a stronger actuator provided the other hardware and mapping is appropriate. Martin - I would consider your mostly stock situation unsuitable for a stronger actuator but you do seem to get away with 16 psi using an MBC. It will drop off because it's a 16t but also because the actuator blows open. I do wonder what a stiffer actuator would do - possibly just incur the wrath of ME7 engine protection because it's a stock ECU but if you are ever near my neck of the woods you'd be welcome to try my actuator and a few different springs. With boost comes risk of course.

[M-R-P]

I've now come to the conclusion that the root cause of my problem is the cheapass mbc I got from eBay. Although the kick in the bum for a few seconds is fun, I don't like the way in which the power drops off.
I wound the mbc back a bit tonight and went for a spin. Boost now climbs to 14psi and takes longer to drop off to 11. Then as the revs climb, so does the boost, back to 14psi. This was tried in 3rd gear as 2nd just wheelspins and imy 4th will double nearly every speed limit in the country before the boost runs out ;)
Although there's obviously less grunt, the power is nicely delivered throughout the rev range.

Gonna leave it alone til I can get my hands on a decent boost controller.

[LiamT4]

I've now come to the conclusion that the root cause of my problem is the cheapass mbc I got from eBay. Although the kick in the bum for a few seconds is fun, I don't like the way in which the power drops off.
I wound the mbc back a bit tonight and went for a spin. Boost now climbs to 14psi and takes longer to drop off to 11. Then as the revs climb, so does the boost, back to 14psi. This was tried in 3rd gear as 2nd just wheelspins and imy 4th will double nearly every speed limit in the country before the boost runs out ;)
Although there's obviously less grunt, the power is nicely delivered throughout the rev range.

Gonna leave it alone til I can get my hands on a decent boost controller.

remap

[M-R-P]

Get yer wallet out then Liam ;)

If I was to gather up the cost of a remap mate, I'd just find something else to spend it on.

Times is 'ard mate, I just gotta do what o can with what little I can find.

I'm still paying for the dim and clutch.

[LiamT4]

Get yer wallet out then Liam ;)

If I was to gather up the cost of a remap mate, I'd just find something else to spend it on.

Times is 'are mate, I just gotta do what o can with what little I can find.

I'm still paying for the dim and clutch.

I'v looked in my pockets and down the side of the sofa, but can't find any pennies to help you out mate ;-)

need the cash myself to get my wheels done, but got other crap to pay for first.........sometimes the money comes in and goes straight out! lol

[Kingsford G]

If want an mbc Forge unos is the 1 to go for,about £65-70
http://www.vividracing.co.uk/forge_unos_boost_controller_ball_spring_mitsubishi _evo_x_08_12_1013503536.php
Remap?I don`t know,£350 and the boost will be about 15-16psi(what u have now with mbc) any more than that with a high mileage engine I wouldn`t do it unless u ready to change it if it goes bang.

[M-R-P]

I'v looked in my pockets and down the side of the sofa, but can't find any pennies to help you out mate ;-)

need the cash myself to get my wheels done, but got other crap to pay for first.........sometimes the money comes in and goes straight out! lol
I may be able to help you with your wheels, if you can get a set to roll on for a week, and get yours to me.

If want an mbc Forge unos is the 1 to go for,about £65-70
http://www.vividracing.co.uk/forge_unos_boost_controller_ball_spring_mitsubishi _evo_x_08_12_1013503536.php
Remap?I don`t know,£350 and the boost will be about 15-16psi(what u have now with mbc) any more than that with a high mileage engine I wouldn`t do it unless u ready to change it if it goes bang.

a remap will give the engine far more than an mbc can. A smooth torque curve, controlled fueling and ignition, not to mention a controlled boost level that doesn't drop off.

Hmmmmm......

[LiamT4]

I may be able to help you with your wheels, if you can get a set to roll on for a week, and get yours to me.


a remap will give the engine far more than an mbc can. A smooth torque curve, controlled fueling and ignition, not to mention a controlled boost level that doesn't drop off.

Hmmmmm......

Cheers but i think my wheels will have to be dipped as they are in a terrible condition.

BTW my car has a nice smooth torque curve ;-)

[M-R-P]

Cheers but i think my wheels will have to be dipped as they are in a terrible condition.

BTW my car has a nice smooth torque curve ;-)

I don't think I need to tell you where you where you can stick your torque curve, but I bet it wrecks the mushy lump you call a gearbox, on it's way to your kidneys ;)

Bloody German Barge :hilarious

[merc85]

Forge Unos MBC mate, never had a spike with that,

[Kingsford G]

I may be able to help you with your wheels, if you can get a set to roll on for a week, and get yours to me.


a remap will give the engine far more than an mbc can. A smooth torque curve, controlled fueling and ignition, not to mention a controlled boost level that doesn't drop off.

Hmmmmm......

As Gav said Forge unos will hold you boost just fine.

[M-R-P]

Yeah, unos hmmm...

I've sneaked everything under the wife's radar so far "Oh that? I just twisted the nut that..."

Can't justify spending more than the price of the lowering springs on it, well, I'll try lol :D

[Kingsford G]

Yeah, unos hmmm...

I've sneaked everything under the wife's radar so far "Oh that? I just twisted the nut that..."

Can't justify spending more than the price of the lowering springs on it, well, I'll try lol :D
Lol,just add it on the cost of the springs.My wife never has any business with what I buy at all as I suppose to be a sensible man but am I?

[M-R-P]

Joint bank account mate :(

The only cash I get away with playing with is what I make on fleabay and I've just blown most of that on sparkly things ;)

[Kingsford G]

Joint bank account mate :(

The only cash I get away with playing with is what I make on fleabay and I've just blown most of that on sparkly things ;)
I see.We don`t have joint `cos mine is a terrible mess lol so she wouldn`t want me in the joint 1.I must get rid of 2 cars quick now and pay my workshop rent.

[jardon]

Quick update - I fitted a yellow (9 psi) spring in my actuator and ran it with the 0.8mm restrictor. It still spikes on spool up but would not hold anywhere near as much boost as with the red (17.5 psi) spring without the restrictor. I take from this that it is mostly increased actuator stiffness that enables my 19t to hold boost at the top end and mid range. The boost restrictor has an influence as it spools faster with it in situ when using the yellow spring even if it won't hold more boost. By using the restrictor I squeeze a little more boost at the top end out of the red spring but in light of the spikiness on spool I am going to trial a larger restrictor. I've said it several times but don't underestimate the performance gain of using a stronger actuator provided the other hardware and mapping is appropriate. Martin - I would consider your mostly stock situation unsuitable for a stronger actuator but you do seem to get away with 16 psi using an MBC. It will drop off because it's a 16t but also because the actuator blows open. I do wonder what a stiffer actuator would do - possibly just incur the wrath of ME7 engine protection because it's a stock ECU but if you are ever near my neck of the woods you'd be welcome to try my actuator and a few different springs. With boost comes risk of course.

Further to the above - my diagnostic process tells me the stock bcs leaks at high boost at full duty. Taking some of the stress off the bcs with a boost restrictor works but makes boost control iffy. A more robust bcs may be the answer - or revised boost control algorithm. The former is DIY so I spoke to Rob (ARD), IPD and Kristian (Snabb). The ARD/Snabb tcv is fundamentally different to a Pierburg unit and will bleed less boost under high load. It might also §§§§ up my boost control altogether. Either way I've ordered one from ARD. Watch this space.

[Wobbly Dave]

I'm running the Snabb TCV - results yet unknown, but they did email me to say it had been tested to 43 psi