997 turbo boost issues ( maybe )

[Fat Porker]

Would like to ask you guys opinions on this , firstly I'm new to this model only had Nat aspirated 991's up to this point but always wanted a gen 1 turbo I think I've bought a stonker as in its like new ,one owner 9 k miles car with impeccable history from Guildford Porsche and a great spec carbon ceramics gt silver etc but I'm not sure even with the ultra low miles it's 100% on song the car drives really smoothly no issues whatsoever other than crippling ride in sport etc which it's booked in at CG as per you guys recommendations for a check and probably the dsc upgrade ,but and this where I'm a bit unsure when fully lit ie WOT in both normal and sport modes it just never really feels as ballistic as I was both hoping and expecting .Now initially I put it down to me being a bit gentle with her as she's now my baby and that the NSX had sullied the waters a bit with its ridiculous acceleration and no lag power delivery but today I noticed that no matter what I did the boost gauge readout in the display hardly ever gets above .6 maybe momentarily.7 bar and then drops off again , it's still fast ish but why 1.2bar in sports mode if it won't show it ? Now am I missing something is this a characteristic of the gen 1 cars or do we think boost leak or n75 valve , diverter valves , actuator rods etc car is stock and has no cel lights on ! Part throttle openings seem fine she pulls sweetly enough but even if I keep it planted it never makes more than described boost , tried to speak to Rick today as he's only an hour away from me but he's out of the country till the 13th and obviously 9e are a way away
From here in sunny Derbyshire lol so I just thought I'd try you amazing lot for a few ideas .
Regards Simon

 

[T8]

You DO have a problem.

The good news is that you'll be ever so pleased when you get it sorted out and feel what it should go like. :drive:

pzero had a very similar issue when he got his turbo and it was something as simple as the Y pipe not being connected properly.

See here -> http://911uk.com/viewtopic.php?t=119071&start=20&postdays=0&postorder=asc&highlight=pipe

 

[Fat Porker]

Thanks t8 I'm just hoping it's not catastrophic mechanical nightmares and something simple pal :floor: just looked through the cars history and literally a few hundred miles ago it had a coolant temp sensor replaced and fresh coolant could they have disturbed something then or does it smack of a decaying sensor of some flavour or another, really appreciate your experience :thumb:

 

[maph]

Firstly congratulations, it looks mint.

On the boost, as Terry has said it is likely to be something simple. I would go with some sort of vacuum leak (split or disconnected hose), or more likely a sticking actuator rod on one of the turbos.

Either way I am sure it will be a simple fix 👍🏻

 

[deMort]

These cars have electric actuators controlling the boost / dump .. the rods can seize holding them open .. i've seen a couple where water has got into the electrical connection and a replacement is required .

Easy enough to check on a ramp .. a bit difficult on the floor ..

When you turn the ignition on these will cycle a full movement of the rods .. you can see if they are going fully up and down basically along with hearing them operate ..

You would need to look at each side whilst someone turns the ignition on engine not running .

There is a high temp grease that's supposed to be applied to the rods .

 

[Fat Porker]

Cheers guys appreciate your input I'll see if I can get it on a ramp for a look as soon as possible , so when all is well you should see more than the .6/.7 bar registered then ?

 

[guyvert1]

Sounds indentical to what I had on mine, probably hose or actuator, mine was a a hose come away, easy fix.

Suspect when you blow the dust of these garage queens a few things need fixing..

Once done though, she should shoot up to 1.2 bar ...

 

[Fat Porker]

You had similar symptoms guy ? And yes I know what you mean regarding garage queens pal she still smells new and I've just had a tot up of service bills and it's twenty bags minimum! 2x 20k services 2x 40k services and service every year in between since 2010 9x oil and filter transmission oil final drive oils brake fluid two sets of plugs and so it goes on but I'm starting to think she could have benefitted from a little more running lol

 

[deMort]

From memory its a 0.8 boost as standard with an overboost of upto 1.1 for 10 seconds ..

I'm sure someone will give the details in a bit .

 

[Fat Porker]

That was what I was expecting having read up on the car Demort
Can the actuators and rods be replaced and at what cost are the parts ?

 

[Mezgerite]

I'm not convinced there is anything wrong with it - 0.6 bar isn't particularly low.

We won't know until we log the requested and actual boost - the dash gauge isn't the best.

However, most turbps I come across will have some issues with boost without the owner even knowing. The following should be done:

1. Log boost pressure actual, requested, and the position of the actuators.
2. Replace the DV valves with GFV metal units as the originals will almost certainly not be sealing completely.
3. Smoke test the intake system to check for any leaks.
4. Pressure test the intake system to ensure there are no leaks while under pressure.

Even if there are no obvious running issues, doing these will nearly always uncover something.

Rick

 

[Gazc2]

From memory its a 0.8 boost as standard with an overboost of up to 1.1 for 10 seconds ..

I'm sure someone will give the details in a bit .

That`s my understanding needs to be in sport mode

 

[Fat Porker]

I'm not convinced there is anything wrong with it - 0.6 bar isn't particularly low.

We won't know until we log the requested and actual boost - the dash gauge isn't the best.

However, most turbps I come across will have some issues with boost without the owner even knowing. The following should be done:

1. Log boost pressure actual, requested, and the position of the actuators.
2. Replace the DV valves with GFV metal units as the originals will almost certainly not be sealing completely.
3. Smoke test the intake system to check for any leaks.
4. Pressure test the intake system to ensure there are no leaks while under pressure.

Even if there are no obvious running issues, doing these will nearly always uncover something.


Thanks for that Rick that's uncanny because I called in at your place yesterday as I was literally across the road at Audi with a friend to look at a car and thought you might be able to take it out for spin and see what you thought Chloe informed me where you were , today I've spoke to a good friend of mine pat from syvecs and in your absence he's said he'd take a look and see if she's happy or not so to speak , I'd love you to take a look at her when your back as I wanted to discuss with you options regarding tune ,coolers exhaust etc . I'll report back on what pat finds in the meantime kindest regards Simon
Rick

 

[IMI A]

If you want to try a tuned one pop down the A1 and have a go in mine one morning. I'd love to have a go in a stock car again.

I don't think these cars need anything other than a tune from someone like Rick, intercoolers, clutch and free flowing exhaust preferably catless if you don't mind polluting.

I have the IPD y pipe, GT3 throttle body and IPD 82mm plenum if of interest. I could never get my throttle response right on it but does add up 35hp top end.

 

[Fat Porker]

If you want to try a tuned one pop down the A1 and have a go in mine one morning. I'd love to have a go in a stock car again.

I don't think these cars need anything other than a tune from someone like Rick, intercoolers, clutch and free flowing exhaust preferably catless if you don't mind polluting.

I have the IPD y pipe, GT3 throttle body and IPD 82mm plenum if of interest. I could never get my throttle response right on it but does add up 35hp top end.

Cheers imi that would be great thanks I'll message when I get her sorted :thumb: