S14 Boost pressure

[Gerry H]

As I know nothing about Nissans.........The car's a 200 SX S14 and owned by a friend of my son.

Fairly standard except for a recently fitted tubular manifold and de-cat system. Since then, it's lost low and mid range power. I've not driven it but this is the owner's observation.

They've had a guy look at it who said it has a Skyline ecu. Stuck a laptop on it and adjusted the fuelling. It's no better. They fitted a boost guage today and it hits 0.5 bar at about 3K revs and won't give any higher bosst except for 5th gear where it gets to 1.0 bar at about 5K revs.

There's also a manual boost controller fitted.

Any thoughts or suggestions? Is this about right? I thought that maybe the manifold to turbo pipe is too big?

TIA

[BenTaylor]

First thing to do would be to check for boost leaks. If its still on the standard intercooler then check it for cracks in the pipework (common prob). If it isn't that then check how the manual boost controller is plumbed in.

Oh and 'Skyline ECU'???

[V8_EATR]

Could be the manifold to turbo gasket may have a leak. Also, could've blow the turbo (worst, but possible case).

[Gerry H]

Thanks for the replies

I gather it's not right then? What boost figures should he be looking for on std. turbo?

The 'tuner' guy also suggested an Apexi PFC which I know is a good bit of kit. Can the S14 ecu be remapped?

[mattie170]

If i remember right .7 bar is standard boost but don't go any higher than 0.9 on standard turbo you will be asking for problems.

I would also check for any leaks on the pipe goin to the acuator, could of caught it on putting it back together then it will run at .5 on the acuator setting.

Matt

[Auto-fibre]

I believe that 10 PSI is standard on the S14, but as mattie said, up to about 15PSI is OK - more is ust asking for trouble.
The standard Nissan S14 ECU is a pretty dumb brick, only slightly smarter than my S13 obbie, so no - in stock form it can't be remapped.
To be honest, I wasn't aware of any Nissan ECU which could be remapped directly except possibly the R34?? Certainly all of the units I have ever looked at used much the same technology, but a variety of chips.

If the guy attached a laptop, the chances are he was reading the CONSULT port - which is the Nisssan Diagnostics port. I'm fairly sure that if it could be re-programmed that way, the 200 community would be aware of it. Since they use either a piggyback such as an Apexi etc or a new mapped chip such as the Horesham developments or Simon Norris chips - my money is that it can't be.

Given that it would appear to be overfueling massively, my money would be on a boost leak, cheak carefully they can be a pain to find.

Strangely one of the best Nissan tuners around these parts is Gary at APT I've always found him most helpful.



Regards

Dwayne

[Gerry H]

Brilliant! Thanks everyone, I'll pass the info on and suggest he starts looking for leaks and contact Gary.

:thumb: