V70 T5 How much is too much boost?

I am trying to understand this boost business!

In the 850 section there is a similar question but this i take it is with the 15g turbo?

I have the uprated engine in my `97 V70 the B5234T3 but with a 16t and HLM304map and i run on 20psi no probs. yet after 2yrs!

I have just purchased an 18T from a member on here smithson007 and am fitting this week so what would be a safe boost psi?

The bit i am trying to get my head around is the fact that the larger turbo the more air it will supply at certain revs so why doesn`t the psi have to be lowered when a bigger turbo
is fitted to be on the safe side.

As an example: if 15G up to 20psi is used and i use on a 16T 20psi surely it is more dodgy using the same psi on the larger turbo.......or am i seeing it the wrong way?

.....and then what happens with an 18T.........does the map sort anything out?

This 18T i have just bought has the straight wastegate and it came off the early V70R so what was different on that motor to keep the engine safe?

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Originally Posted by 960kg

I am trying to understand this boost business!

In the 850 section there is a similar question but this i take it is with the 15g turbo?

I have the uprated engine in my `97 V70 the B5234T3 but with a 16t and HLM304map and i run on 20psi no probs. yet after 2yrs!

I have just purchased an 18T from a member on here smithson007 and am fitting this week so what would be a safe boost psi?

The bit i am trying to get my head around is the fact that the larger turbo the more air it will supply at certain revs so why doesn`t the psi have to be lowered when a bigger turbo
is fitted to be on the safe side.

As an example: if 15G up to 20psi is used and i use on a 16T 20psi surely it is more dodgy using the same psi on the larger turbo.......or am i seeing it the wrong way?

.....and then what happens with an 18T.........does the map sort anything out?

This 18T i have just bought has the straight wastegate and it came off the older 850R so what was different on that motor to keep the engine safe?

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you are correct i bent my rods recently with 18psi on my 19t, yet with my 18t i ran 22 psi for months (then bent a rod)

can u ?

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Originally Posted by WOODY T5

can u ?

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can u?

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Originally Posted by 960kg

I am trying to understand this boost business!

In the 850 section there is a similar question but this i take it is with the 15g turbo?

I have the uprated engine in my `97 V70 the B5234T3 but with a 16t and HLM304map and i run on 20psi no probs. yet after 2yrs!

I have just purchased an 18T from a member on here smithson007 and am fitting this week so what would be a safe boost psi?

The bit i am trying to get my head around is the fact that the larger turbo the more air it will supply at certain revs so why doesn`t the psi have to be lowered when a bigger turbo
is fitted to be on the safe side.

As an example: if 15G up to 20psi is used and i use on a 16T 20psi surely it is more dodgy using the same psi on the larger turbo.......or am i seeing it the wrong way?

.....and then what happens with an 18T.........does the map sort anything out?

This 18T i have just bought has the straight wastegate and it came off the early V70R so what was different on that motor to keep the engine safe?

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It's the way the torque comes in that will kill your engine, with the 18 being larger it will produce more grunt, as said many times before it will be fine if you dont floor it low down

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Originally Posted by Jamest5r

It's the way the torque comes in that will kill your engine, with the 18 being larger it will produce more grunt, as said many times before it will be fine if you dont floor it low down

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Saying not to boot it low down is sound advice but kinda defeats the object. So basically, you sacrifice all that low down torque for some power at the top end. Most people spend 90% of the time in the mid range so to have to hover over the throttle until 3500rpm would make the car frustrating to drive. My old 850 was a pain for the same reason. Constant worry about bending a rod. The reason I find my T4 so great to drive is that the low down 300lbft gives incredible driveablility. Reving out to 6000rpm is very rare unless I feel like driving like a bell end. I think the key is to bin the MBC and have the ecu have control of the boost using a progressive (rod friendly) boost map by a competent mapper such as Tim Williams or Shark.

What keeps the engine safe on the V70R as opposed to your car is that on the V70R the stock ecu has control over boost with the bcs, Volvo will have mapped it with engine limitations in mind as they do on every car. You have overridden your ecu using an MBC so that safety parameter is now lost. If you use the BCS you will find HLM would have limited the boost to 16psi for the same very reason. Rod/engine preservation.

Also Keith about the query about psi on a bigger turbo yes you are right. At the same psi an 18T will deliver more air to the cylinders than a 16T so more chance of damage at the equivalent boost. The only minor way the 18T would reduce the chance of damage is that it will spool slightly higher in the rev range.

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Originally Posted by T5frankie

can u?

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mbc?

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Originally Posted by 960kg

I am trying to understand this boost business!

In the 850 section there is a similar question but this i take it is with the 15g turbo?

I have the uprated engine in my `97 V70 the B5234T3 but with a 16t and HLM304map and i run on 20psi no probs. yet after 2yrs!

I have just purchased an 18T from a member on here smithson007 and am fitting this week so what would be a safe boost psi?

The bit i am trying to get my head around is the fact that the larger turbo the more air it will supply at certain revs so why doesn`t the psi have to be lowered when a bigger turbo
is fitted to be on the safe side.

As an example: if 15G up to 20psi is used and i use on a 16T 20psi surely it is more dodgy using the same psi on the larger turbo.......or am i seeing it the wrong way?

.....and then what happens with an 18T.........does the map sort anything out?

This 18T i have just bought has the straight wastegate and it came off the early V70R so what was different on that motor to keep the engine safe?

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I`m running a 19T hybrid with whites and a HLM304 map, When I boot it from a stand still and the map limits the boost to 1/2 bar until the revs are over 3k then the boost climbs to 1 bar.

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Originally Posted by oblark

I`m running a 19T hybrid with whites and a HLM304 map, When I boot it from a stand still and the map limits the boost to 1/2 bar until the revs are over 3k then the boost climbs to 1 bar.

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Thanks.so I think the key point here for safety is to let the map dictate the boost as it has been set with safety in mind. If you want more than what the HLM map is set to (1bar -ish) then you will need to get it mapped again to raise the limit.

1.35 bar here from 2k on volvo rods!

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Originally Posted by WOODY T5

1.35 bar here from 2k on volvo rods!

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Fair play. I think maybe keith should try this and see if his engine can take the same? Would be interested to see if it would be ok. We have your car as living proof of how strong the Volvo engine can be and a string of broken engines and bent rods showing how weak it can be too lol

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Originally Posted by WOODY T5

1.35 bar here from 2k on volvo rods!

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That's commendable, do you run increased boost levels at higher revs as well or does it stick to 1.35 bar throughout the rev range?

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Originally Posted by mitchyboy01

Thanks.so I think the key point here for safety is to let the map dictate the boost as it has been set with safety in mind. If you want more than what the HLM map is set to (1bar -ish) then you will need to get it mapped again to raise the limit.

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Agreed, best to leave the boost control to the ecu and perhaps invest in a custom map to increase the boost a little if your not happy with it as it stands currently.

nah andy 1.35 all the way can run 1.45 to mate with no probs:) think it just shows how good the mte custom map is to

Thanks all for the replies.......and yahoooo!..... i am having a 2 1/2" Ferrita stainless exhaust system fitted tomorrow along with the 18T.......presently having my 98th childhood gotta keep my old greycells active!

I have taken off the MBC and put back my new TCV/BCS which i had only used for a hundred miles....so back to basics and see how she goes. I will play with the actuator and just learn again what to do.

Will report back what i have noticed and what psi i am gradually going to go to. May even have a vid. of the noise....if i like it!!

Keith

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Originally Posted by 960kg

..... i am having a 2 1/2" Ferrita stainless exhaust system fitted tomorrow along with the 18T.......

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We all expect a full write up and piccy's tomorrow then !

If it stops BL raining!......

Just been reading your other thread Graham about cat back exhausts......interesting...

Well had my 18T fitted today by a forum member and what an exciting day, the turbo went all very smoothly as far as fitting goes and used all new banjo washers and gaskets etc.

While he was doing the turbo i supplied his mate was doing fitting the 2.5" Ferrita cat back exhaust, although 2nd hand it is of course in excellent condition being stainless steel and not very old.

Well after the fitting went for a trial spin along the A2 in Kent dual carriageway and as i had refitted the Volvo BCS i was not impressed in 1st & 2nd gear boost but was impressed by it`s smoothness the engine sounded like a turbine and the 18T when on boost was just sounding like an aero engine but quieter....my old 16T although in good nick clearance wise when checked later was very oily and the seal had gone but it used to be noisy when boosting and sounding nothing like this 18T.....

When into 3rd it started to happen better through the BCS and the boost went quickly to the same 20psi and also in 4th held the same 20......but the smoothness is very very noticeable...

The grunt did happen later in the revs unlike my 16T which was earlier with 4 turns of the actuator on the 18T it is set at 2 turns.

The HLM 304 did not restrict the boost back to 16psi with the BCS it seems as though it has completely removed it as i can still set the boost at what i like!

I will give it a couple of days for the ECU 4.4 to adjust itself and then will probably give the actuator another turn making 3 turns from standard.

After that i may try a decent MBC but only to 20psi and from 3000revs and see what happens.

My old cheapo MBC has been set on 20psi for 2yrs with the 16T set on 4 turns of the actuator and i did like the point and shoot attitude of it
this set up now seems more power on the move higher up the rev band so of course at a higher speed not quite what i wanted but i may get the result i want by just progressing slowly and surely!!

Above all i am not sorry for the upgrade and the smoothness of the engine and the smooth delivery of the power is so really noticeable.

I struck lucky with the 18T as it had been refurbished at a cost of £389 only some 8000mls ago and i bought it for £200....the Ferrita was 2nd hand and was £200 FITTED so together with the fitting of the turbo £50 the cost was a mere £450 in total so all in all not a bad days work!

Keith

Sounds like a great day's work, and those prices are great.

You have highlighted a problem that has stopped me going for an 18t and that is it takes a bit longer to 'get moving'.....I think I'll stick with my 16t a little longer.

Glad your happy with the results.

Told you the turbo was like new :) glad someone's enjoying it.