Having got my boost controller up and running I now seem to be only able to hit 14/15psi Max whereas I was previously up to 22psi. I've checked the ecu for error codes and got a 55 all clear. I checked the hoses visually but what I really need is to do is check for leaks.

 

Is there anyone in or close to Croydon that might be able to help out? I'm heading to Santa Pod on the weekend with some mates and it sucks I'll be down on power.

 

Thanks in advance!

 

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>15psi

>down on power

Lol

 

Never done it myself but somepeople say to put washing up liquid around the joints and see when reving if they bubble up.

 

-------Updated--------

 

The only 'mechanics' i know that could give you a hand are Terry, and Ash, not too close but might be able to pop down and give you a hand.

Edited February 22, 20169 yr by Alic

I used the smoke match technique to fill intake with smoke, pressure tested and find joints where it leaks...... I found a hose completely off under N/S headlight!

The what technique??

 

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Fitted boost tester in place of the MAF with a croc clip fixed to the back of it then put a smoke match in the clip, it then fills the intake pipes with smoke. Pressure up the system as though you are doing boost leak test and see where the smoke is forced out.

Makes it easy to spot a loose hose clip, split pipe, etc...

Can't remember who suggested it..... but it showed my small pipe had come off that I couldn't find before doing this....

if a tyre has a puncture it will still inflate to its working pressure so the fact your car makes 15 tells me its probaly the ebc install or set up Vig.

Have you checked that the max boost setting is still set to 22psi. Also you may have a high/low boost function selectable

on your EBC (mine does) with it now in low boost setting.

Have you checked that the max boost setting is still set to 22psi. Also you may have a high/low boost function selectable

on your EBC (mine does) with it now in low boost setting.

 

It doesn't have a hi/lo setting as far as I'm aware. Not sure if I'm just being a plonker - note sure where I got the 21psi figure from. Dyno shows 19psi was peak when mapped. It has been tinkered with subsequently to fix some over fuelling so perhaps it was brought down. It still pulls great with steady boost. Just went out and managed 16.6psi (read off the EBC peak) which isn't terrible.

 

Starting to think I may just be looking for faults where there aren't any.....

Happy to help mate :)

>15psi

>down on power

Lol

 

Never done it myself but somepeople say to put washing up liquid around the joints and see when reving if they bubble up.

 

-------Updated--------

 

The only 'mechanics' i know that could give you a hand are Terry, and Ash, not too close but might be able to pop down and give you a hand.

 

When an engine is running it puts its intake into negative pressure, aka vacuum. This means it's sucking in, it's only in the case of forced induction that the intake becomes partially positive pressure, aka boost. Our cars like a lot of turbo cars won't make much boost if any at standstill unless it's really revved hard. Say 2psi at 5.5k rpm. That flash of 2psi wont tell you much. What I'm saying is your method won't work, you will simply suck in washing up liquid. What you could do in that respect is spray an accelerant on the joins and wait for the revs to spike. Rather a long winded process best left for NAs.

 

Without doubt the best option available to the home/diy mechanic is to apply pressure to the entire intake system, via a compressor, small tyre inflator ones you get in some cars aren't man enough. You can usually get something useable for about £100. Pressurise the system to a preset value, I chose 5psi as per the service manual. The reason being applying pressure to the pre turbo section, vacuum area pressurises the oil galleries via the front valve cover breathers. This potentially could pop out an old seal. If you have deleted the pcv this is moot. Some, will push more pressure through say 14psi, this would be at your own risk though. You can then listen for the hisses and use soapy water to locate the offender, which will go like bubble bath. Alternatively you can add a smoke pellet as Russ suggested.

It doesn't have a hi/lo setting as far as I'm aware. Not sure if I'm just being a plonker - note sure where I got the 21psi figure from. Dyno shows 19psi was peak when mapped. It has been tinkered with subsequently to fix some over fuelling so perhaps it was brought down. It still pulls great with steady boost. Just went out and managed 16.6psi (read off the EBC peak) which isn't terrible.

 

Starting to think I may just be looking for faults where there aren't any.....

 

 

What turbos are they vig? 21psi is a lot and I'd be surprised if that's what they were set up to unless you had some GTX turbos or something. I'd give you a hand if you weren't so far away. I'm actually in Croydon Thursday but I'm on a tight schedule.

They're GT535Rs. Correction to the 21psi...not sure where I imagined that number from. Dyno shows 19psi. As said above I'm thinking that I may just be looking for issues where there aren't any. The car is driving and boosting smoothly (and holding it) so think I'll leave it be for now. Appreciate your offer for assistance though, thanks very much!

 

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No problem. This is where an AFR gauge comes in handy, just for peace of mind. As Jimmer said, if it's making 15 that's a good sign really. If you were struggling to produce the 16 you recorded, ie you used to hit full boost at 4krpm now it's not till 5.5krpm, then I'd be concerned.

It really would be sensible to test it out.

It doesn't have a hi/lo setting as far as I'm aware. Not sure if I'm just being a plonker - note sure where I got the 21psi figure from. Dyno shows 19psi was peak when mapped. It has been tinkered with subsequently to fix some over fuelling so perhaps it was brought down. It still pulls great with steady boost. Just went out and managed 16.6psi (read off the EBC peak) which isn't terrible.

 

Starting to think I may just be looking for faults where there aren't any.....

 

They're GT535Rs. Correction to the 21psi...not sure where I imagined that number from. Dyno shows 19psi. As said above I'm thinking that I may just be looking for issues where there aren't any. The car is driving and boosting smoothly (and holding it) so think I'll leave it be for now. Appreciate your offer for assistance though, thanks very much!

 

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Hi Vig.

 

I've got your turbos down as 530bb items. Nothing to say that boost was reduced on the 21/09/2014, no reason why it would have been altered it to be honest :)

What turbos are they vig? 21psi is a lot and I'd be surprised if that's what they were set up to unless you had some GTX turbos or something. I'd give you a hand if you weren't so far away. I'm actually in Croydon Thursday but I'm on a tight schedule.

 

21psi is only 1.4 bar, even standard turbos are good for a peak of 1.7 bar if the system can support it (I posted Garrett's compressor maps for the TB22 on the forum ages ago, and ran this figure myself for about a year on the original 115k auto turbos to achieve 482lb·ft @ 3900rpm).

 

GTX turbos don't start doing what they're built to be doing until 30psi/2 bar, generally-speaking. Any less than that and you've just spent a lot of money for no real benefit over regular ball-bearing units :)

Noel - the spec sheet I sent you before the mapping has them down as Z1 GT535s. I had a John Dixon 530bb chip installed though.

 

As I mentioned on pm, the settings on the ebc are different to what you confirmed had been set on the dyno so perhaps it has changed due to being powered down etc. I'll try setting up for programs again as per dyno and go from there. Feeling much more optimistic about it all now though. Cheers for he help!

 

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21psi is only 1.4 bar, even standard turbos are good for a peak of 1.7 bar if the system can support it (I posted Garrett's compressor maps for the TB22 on the forum ages ago, and ran this figure myself for about a year on the original 115k auto turbos to achieve 482lb·ft @ 3900rpm).

 

GTX turbos don't start doing what they're built to be doing until 30psi/2 bar, generally-speaking. Any less than that and you've just spent a lot of money for no real benefit over regular ball-bearing units :)

 

Closer to 1.5 bar really, if you wish to be anal. Anyway. I stand corrected. I was under the impression stock turbos were out of their range at 17psi. And that gt2554s peaked efficiency at 19psi. However I was aware that GTX turbos don't really shine until you are making far higher than 1bar.

Closer to 1.5 bar really, if you wish to be anal. Anyway. I stand corrected. I was under the impression stock turbos were out of their range at 17psi. And that gt2554s peaked efficiency at 19psi. However I was aware that GTX turbos don't really shine until you are making far higher than 1bar.

 

 

No matey, I have no inclination to get into a pissing contest about basic mathematics. Surprised you can be bothered to pull me up on something so trivial :huh:

 

One thing, though. 21psi is precisely 1.447899408 bar. Closer to 1.4 bar actually, if you wish to be anal :laugh:

 

The point I was alluding to is that the attainable boost pressure at the business end in a 300zx TT is dependent on the setup. The only reason people think/thought that XYZ turbo tails off and is therefore unable to sustain boost is actually due to the massive restriction in the stock setup. Remove the intake piping & MAF, construct a modified intercooler and keep the charge piping as short as possible. Only then will you get a better understanding of what XYZ turbo is really capable of delivering to the intake manifold in a Zed engine bay.

 

Aside:

As a controlled experiment on the dyno, I ran a pair of GTX2680 turbos with the actuator reference lines disconnected in a drifty Zed. 1.8 bar at the intake was all that they could produce with the supplied actuators and a single intake. The car was over 600bhp anyway, so it wasn't all doom & gloom!

Noel - the spec sheet I sent you before the mapping has them down as Z1 GT535s. I had a John Dixon 530bb chip installed though.

 

As I mentioned on pm, the settings on the ebc are different to what you confirmed had been set on the dyno so perhaps it has changed due to being powered down etc. I'll try setting up for programs again as per dyno and go from there. Feeling much more optimistic about it all now though. Cheers for he help!

 

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Ah, of course. Just been through the spec sheet again, my mistake :D

No matey, I have no inclination to get into a pissing contest about basic mathematics. Surprised you can be bothered to pull me up on something so trivial :huh:

 

One thing, though. 21psi is precisely 1.447899408 bar. Closer to 1.4 bar actually, if you wish to be anal :laugh:

 

The point I was alluding to is that the attainable boost pressure at the business end in a 300zx TT is dependent on the setup. The only reason people think/thought that XYZ turbo tails off and is therefore unable to sustain boost is actually due to the massive restriction in the stock setup. Remove the intake piping & MAF, construct a modified intercooler and keep the charge piping as short as possible. Only then will you get a better understanding of what XYZ turbo is really capable of delivering to the intake manifold in a Zed engine bay.

 

Aside:

As a controlled experiment on the dyno, I ran a pair of GTX2680 turbos with the actuator reference lines disconnected in a drifty Zed. 1.8 bar at the intake was all that they could produce with the supplied actuators and a single intake. The car was over 600bhp anyway, so it wasn't all doom & gloom!

 

Just yanking your chain Noel, tone is lost with text sadly.

 

I thought you may say that. I was under the impression that the quoted figure were based upon the characteristics of the cold side. Ie bench testing, not including the other factors. Obviously not. Interesting stuff.

Just yanking your chain Noel, tone is lost with text sadly.

 

I thought you may say that. I was under the impression that the quoted figure were based upon the characteristics of the cold side. Ie bench testing, not including the other factors. Obviously not. Interesting stuff.

 

Hahaha, yeah it is! Wondered what was going on there for a moment dude :pint:

 

No, you're right. The quoted figures (compressor maps) will be regardless of external setup or application, and are based on the aerodynamics of the blades (size, trim, etc).

 

Back in the day I've read of people stating the stock turbos were simply blowing hot air after 1 bar. Maintaining boost in a Zed is the trick to decent power. I was able to hold 1.4 bar on my auto turbos to the redline, and that was with standard manifolds & elbows.