T5 standard boost pressure

[Turbodave]

Evening...

Could be in line for the blonde of the year award here but I'm in need of some pointers on standard boost. Just aquired a 94 T5 which is standard and done a few miles. When it's on boost, ie loading it up in say 3rd and 4th the little gauge only just moves into the "white" zone and likewise when coasting it drops just into the open area.

Appreciate this gauge is probably is as acurate as Stevie Wonder with a shotgun, but having had other turbo cars I'd have expected the gauge to be a bit more enthusiastic? On a standard car, roughly what should it hold boost at (on the gauge...) and also do these things have an overboost... ie will it boost to say 15PSi then hold a constant 10PSi (or is that optimistic?)

I'm fairly sure I have a boost leak somewhere as theres a nice wee whistle when the turbo wakes up... may libertate the gauge from my other car just to try it and see what it's actually doing.

Any pointers greatly appreciated.

Thanks

[irf]

no overboost unless it's an R.

standard boost pressure is 9.6psi.

the standard gauge reads up to about a bar of boost so definetly sounds like a boost leak.

check your boost pipes, if old, replace. also, the same with the elbows as well.

[cameron]

Probably an old question Irf but what is the boot pressure if its boosting off the end of the white section ?

Was good to meet you Saturday mate :B_thumb:

Cheers

Lee

[Volvostorm]

Sorry to hi-jack, but can you/ could you fit an R ECU to a normal T5

I'm guessing a re-map is easier :)

[cameron]

Oi theres a place in America for Hi-jackers :rotfl:

Thats an interesting question Paul, Why do you ask, have you something in mind ?

Cheers Bud

Lee

[Enigma666]

In theory there should be no real difference....a manual R had the 16T though as opposed to the 15G so that could be an issue, also depending on what injectors were used you could find yourself with increased duty cycle on standrad injectors etc.
All in all should be fine though :)

[Volvostorm]

Was just a thought, as anouther way of increasing outputs on the car, your get the overboost for a start.

Its also quite common in other cars to swap ecu's around, I know of more that one Escort RS turbo controlled by the Sierra RS Cosworth ECU

Surely, the 15G flows less, so the R ecu will 'see' this, and adjust the fuelling to suit? Has anybody tried it?

[Enigma666]

Not likely with the fuelling...it's possible I suppose but not highly likely.
There will be small compensations made by the ecu but the R map was more aggressive...do they use the same cams for example as that could cause issues with lift and duration...well timing in general.

[Volvostorm]

Don't know about the cams, maybe somebody here will know :)

Or, is anybody brave or 'stupid' enough to try it? It has two chances.

I know the ECU on my 24v Sierra isn't the right one, its off a 12v version, yet, it smoother, and gets more power:cool:

I don't know why it does, my friend was running the ECU I have in there, and he spend hours running tests on his car AFR, fuelling etc, and all he could find was it made the engine run slightly richer at WOT, which isn't a too bad a thing.

Ok, we are talking about completely diffirent engines, but I think it maybe worth a try, and see what happens

[Enigma666]

Kez-T5R has a superchips one for sale, perhaps have a word with them?

[Turbodave]

Soooooo.... going back to the original question, roughly where on the little guage should it boost to? As in how far into the white area (dead technical I know but hey...) as in 1/4... or more like a 1/2? Really can't be arsed butchering my other car to fit it's boost gauge. I did have a check of the boost pipes but there's nothing obviously... one thing I did notice was the actuator arm seemed a little loose, is it worth putting another turn on the nut to compensate for a few years worth of use?

Not looking to spend any cash as such... well, not a King's ransome

[t5 pete]

As irf has said 9.6 psi and its about 3/4 into the white gauge normaly the end of the white gauge reads about 14psi

[irf]

just to clarify something as it may not be clear.

only the manual 850R has the 16T, the auto version and all 850 T5-Rs have the 15G.

the engines in all are the same, that includes the cams, rods and everything, it's only the ecu.

there is some debate on the 850R rods but i have been told by a couple of reliable people that they are the same.

also, the T5-R ecu will fit as long as both cars are the same with regards to being an auto or aircon etc. i cant say about the 850R manual ecu working in a 850 T5 manual though as i honestly don't know.

if the manual 850R came with orange injectors i'd be fine giving it a go but i do have a wideband to be able to keep an eye on things.

Dave, it depends on how loose it is, is it floppy or do you still need to pull the actuator arm to get it on to it's slot?

9-10 psi would correspond to about two thirds or three quarters into the white but you really should chuck the boost gauge on to get some accurate info.

[tandino]

Its also quite common in other cars to swap ecu's around, I know of more that one Escort RS turbo controlled by the Sierra RS Cosworth ECU



Seeing as the RS turbo ran mechanical KE jet fuel injection vs the Cossie running Weber Marelli i very much doubt it!!!.
Bottom line is the manual R's ran with white injectors so your duty cycle will be all over the place...

[tandino]

Soooooo.... going back to the original question, roughly where on the little guage should it boost to? As in how far into the white area (dead technical I know but hey...) as in 1/4... or more like a 1/2? Really can't be arsed butchering my other car to fit it's boost gauge. I did have a check of the boost pipes but there's nothing obviously... one thing I did notice was the actuator arm seemed a little loose, is it worth putting another turn on the nut to compensate for a few years worth of use?

Not looking to spend any cash as such... well, not a King's ransome

As a rule of thumb the actuator arm should have a little preload over the wastegate pin, if the spring has become weak and there is no preload then adjust it so that it does preload on the wastegate pin.

[Saaamon]

Seeing as the RS turbo ran mechanical KE jet fuel injection vs the Cossie running Weber Marelli i very much doubt it!!!.
Bottom line is the manual R's ran with white injectors so your duty cycle will be all over the place...

I think pault5estate was being abit broad with what he was saying, there are series 1 and 2's out there that use cosworth management as an after market mod but this is on EFi's and to use it you need to add extra sensors as well as the supporting mods.

Saaamon

[Turbodave]

Excellent lads, mine is barely getting into the white section therefore there's definately an issue. given the slight whistle under boost means I'll have a better look at the pipes and vacuums in the morning... is there any known issues, any certain pipes that can rub through or split?

With regards to the actuator, the rod itself is a little loose but I'd put that down to the linakge wear and such like but the preload seems ok, can perhaps move it out a couple of mill at the most without too much effort. Thing being, the car appears to hold boost so this wouldn't suggest a boost leak or a weak actuator, so could just be things sagging with age... so a couple of turns shouldn't hurt. In theory.

[tandino]

I think pault5estate was being abit broad with what he was saying, there are series 1 and 2's out there that use cosworth management as an after market mod but this is on EFi's and to use it you need to add extra sensors as well as the supporting mods.

Saaamon

I know people retrofit Cossie Weber management but that is a complete swap shop not just a plug and play ECU swap which is a tad different to swaping an ME ecu for our Tanks:partysmil


Excellent lads, mine is barely getting into the white section therefore there's definately an issue. given the slight whistle under boost means I'll have a better look at the pipes and vacuums in the morning... is there any known issues, any certain pipes that can rub through or split?

With regards to the actuator, the rod itself is a little loose but I'd put that down to the linakge wear and such like but the preload seems ok, can perhaps move it out a couple of mill at the most without too much effort. Thing being, the car appears to hold boost so this wouldn't suggest a boost leak or a weak actuator, so could just be things sagging with age... so a couple of turns shouldn't hurt. In theory.

Your on the right track and checking for boost leaks is the first step, you sound like you know what your doing.
Easiest way is to make a home brew pressure tester, bung with a schraider valve and pressurise with a bike pump,i used to have a kit for my Audi S2, saved alot of time!!

[Volvostorm]

I think pault5estate was being abit broad with what he was saying, there are series 1 and 2's out there that use cosworth management as an after market mod but this is on EFi's and to use it you need to add extra sensors as well as the supporting mods.

Saaamon

Yes, i should have masde my point a bit more clear, thank you :)

Alot of the RS tubby boys do junk the K-jet in favour of EFi system

[Volvostorm]

just to clarify something as it may not be clear.

only the manual 850R has the 16T, the auto version and all 850 T5-Rs have the 15G.

the engines in all are the same, that includes the cams, rods and everything, it's only the ecu.

there is some debate on the 850R rods but i have been told by a couple of reliable people that they are the same.

also, the T5-R ecu will fit as long as both cars are the same with regards to being an auto or aircon etc. i cant say about the 850R manual ecu working in a 850 T5 manual though as i honestly don't know.

if the manual 850R came with orange injectors i'd be fine giving it a go but i do have a wideband to be able to keep an eye on things.

.

Thanks Irf, This is what I was trying to find out :)

[Turbodave]

Easiest way is to make a home brew pressure tester, bung with a schraider valve and pressurise with a bike pump,i used to have a kit for my Audi S2, saved alot of time!!

Funnily enough, I mentioned this on another forum and got laughed at. My "other" car is a turbo too and has 3" stainless steel boost pipes and seems to suffer boost leaks regulary, so my plan was to drill a small hole in one of the pipes and fit a car tyre valve then seal it. Thus I figured I could pressurise the system and look for leaks.

Granted it can't check the entire system as it's never gooing to be 100% air tight but by making a temporarly seal at the air flow meter and throttle body you could in theory test smaller sections of the intake system, I figured it'd be good for testing the intercooler and it's pipework but then again wouldn't be any good on the vacuum system. But if anybody has any suggestions, it'd be appreciated.

Really don't want this thing to turn into another project... however I do want it to be right and the fact it's boost like an asthmatic on a fag break isn't good, no point trying to find more power if it isn't even making standard power.

[Turbodave]

Further information needed gents...

Successfully removed the turbo heat shield (fun...) and had a look at the actuator adjustment in a view to curing why the car is boosting so low on the gauge. I've removed the actuator arm from the wastegate arm, with the wastegate full closed I need to pull the actuator rod out about 2mm in order for it to locate on it's pin. Now to me, that should be enough preload... however given it's age, would it be worth winding the arm in a turn or two, in essence increasing the preload??

I've also checked the vacuums and boost pipes as best I can and can't see anything obvious bar the inlet boost hose that runs from the intercooler over the head and into the turbo seems very loose, but assume this is due to it being rubber mounted where it meets the turbo. Dunno who decided canting the engine over backwards and then hiding teh turbo under the master cylinder was a good idea, Sven needs his arse kicked. There has already been blood lost and a ratchet launched across the workshop!

Car's now in bit's and it's started to rain... sense of humour bypass en route shortly.

Regards

[Turbodave]

Actually ignore that, I'm talking ££££££££... to increase boost I'd need to lengthen the actuator arm slightly as shortening it will reduce how much the wastegate opens. I'll adjust it so it slips over the rod without any need to haul the actuator out and take it from there. See if I can regain some of the boost that seems to have escaped. I don't really want to go faster, I just want it to run at factory levels.... car just seems slow compared to my Cavalier (he says, ducking to avoid the incoming fire for that one)

AA is 0800 838 1122 right?

[timbo_1975]

Shorten the rod to increase pre-load. There is a figure at which to set it - 3psi OTOH - the rest is achieved by the ECU modulating the BCS.

Find and seal your boost leak first though.

Tim.

[Turbodave]

We've been fiddling about with this all afternoon to little avail.

As an experiment I increased the length of the actuator rod so in effect there was no pre-load on the actuator and gave it a try. When stationary and revved, there was a increased "dump" or "flutter" if you like and on a run under boost in the higher gears the turbo whislte was increased and the dump/blow off valve seemed more pronounced.

I then adjusted the rod again to give more preload and tried again, less noticeable turbo whistle (which I understand) but what got me was the boost gauge read the same in both instances despite the actuator being adjusted both longer and shorter than the original position. So, went and did some googling and as far as I'm lead to believe... these things will self regulate the boost? So even winding in the rod, the car/ecu/whatever will compensate for this and maintain a pre-determined PSi?

I'm used to barn door engineering where winding in the actuator would increase the boost levels untill the ECU saw a boost pressure outwith it's factory limit and then shut itself down. To get round this, remap the ECU and wind the actuator up. But again, I'm not looking to increase over factory... just want back what's escaped and given the gauges reluctance to move, I assume it's lost something.

Shoudl have bought a BMX

[BruceT]

If you wind the acuator in, it should allow slightly more boost for a few seconds, untill the ECU see it and knock it back to factory.

Linky:
http://au.geocities.com/ozbrick850/engine-turbo-keithspage.html


So now you have a “tweaked” turbocharger – what are the advantages and disadvantages?

The “base line” boost of the turbocharger has been increased to 6 psi – meaning that the impeller blades are allowed to “idle” faster than before on part throttle opening. This means that boost is available sooner when the throttle is opened wide - hence it has the effect of reducing turbo “lag”. However, as the baseline boost is now higher and the turbocharger can build boost much more quickly than before, it can also spike more easily before the ECU has time to make corrections.

So the delay introduced by leaving the ECU in line means that it is now much easier for a boost “spike” to exceed safe parameters and the ECU may react by cutting off the fuel to the engine. Secondly, the ECU is still measuring the output of the Mass Air Flow sensor. It will react to the higher volume of air entering the engine by reducing the boost pressure via the wastegate solenoid valve. The onset of “knock” will cause the ECU to retard the ignition and also to back off the boost level. Luckily it does take a finite time to do so - therefore there is an increase in boost but only for a short time, until the ECU returns it to what it considers to be “normal”. [This isn’t as bad as it sounds – carefully study this extract from one review on the T5R.

“The R's engine management system has been programmed to allow the turbocharger to kick boost from 9.6 psi to 10.9 psi in 7-second bursts during maximum acceleration. This ups the horsepower rating to 240”.

[irf]

personally i think it could be one of three things or all three:hidesbehi

1. boost leak(most likely and common as muck)

2. turbo on it's way out

3. knackered cat

[Turbodave]

Righty ho... well, went back and had yet another attempt. I shortened the actuator back to how it was before I decided to go poking, then added another couple of turns so in effect increasing the pre-load. I figure with the wastegate fully shut, I need to pull the actuator about 4mm forward to locate the pin (if that makes sense) Went for a run and to be fair, it's alot better. I would say it does reach slightly higher up the gauge and does seem to pull a tad harder before settling down. So all in all, I'm happy with that.

Regarding what could be wrong... I doubt it's the turbo as it doesn't smoke at idle or under boost, there are no oil leaks nor is it burning oil through the exhaust and I checked for play in the wastegate bearings with it disconnected and they had no play. The catalyst, again I dooubt it as the car was only MOT'd on Friday and passed emissions with flying colours (I was surprised to say the least) and to make sure, I checked the cat and it appears reasonably new (as does the whole exhaust)

So... yes, boost leaks. I still maintain it does sound very noisey under boost. What I can't decide is if they just are fair intrusive turbo's or if it's boost leaking. Id does sound like a leak, it's not really a whistle... more a whooshing noise followed by a destinct flutter when you come of the power. Again, I'm not familiar with the blow off setup on these nor how intrusive they are, but under held boost it does sound a bit airy.

So, with the actuator sorted... any ideas on where to go looking for boost leaks or how to fault find? I have visually checked as much as possible and even witht he car ont he ramp and suspended and doing 4th gear foot to floor sessions, it's not obvious where the whoooshy noise is coming from. Suggestions?

Here endeth War and Peace for the time being!

[PNuT]

if its fluttering your recuirc valve is not working..... check the pipework too it....

[Turbodave]

Ironically, today it's all but stopped being intrusive. We have a road here btween two high walls, up a hill which is great for doing window down echo spec diagnostics with a keen ear... and today it was fine, still can here it boosting away but now it just has a wee sook noise when you change gear, much like a something opening... like a bottle of coke. Still drives fine, pulls fine and reads fine on the gauge. Truth be told, I'm reluctant to start poking around too much now!

I'll have a wee check of the pipework but can the recirculating valve split and leak boost? Assume it's just in essence a rubber sealed vacuum controlled valve so if it wasn't sealing during boost it'd leak and make a noise. Blanking it off would seem like the better option but really don't want to put an atmospheric valve in it's place but if it solves the potential issues then so be it... process of elimination as usual!