So I went on the dyno today, but unfortunatly I didn't complete a run.

 

3 weeks ago, my o/s standard turbo decided it didn't want to be a turbo again, and it was absolutely kerfuffled. Smoking like a good'un and making a horrid grinding noise.

 

Fitted some GT25 hybrid turbo's by Turbo Technics (supplied by Kinugawa Turbo on here) and I ran it in a little bit. I've done about 60-80 miles since fitted and at first it was idling pretty bad, with old oil pluming out of the exhaust still. It has since cleared up, and before the dyno run, I got it up to temperature, and made sure that it was given a decent run out before it went on the rollers.

 

When it came to the run, it was throwing a lot of smoke out of the back where the buggered turbo was, and the air fuel ratios were showing 14 at half throttle, and 17 at idle. Now, I'm a bit dim, but I don't know what that is. They said it was running lean (which I had suspected), but what should be the course of action to take?

 

It did make 108bhp at 3.25k RPM though, which is barely in boost :D

thats proper lean for a turbo car althogh it prob wont richen up until its on boost, probly needs mapping id keep well away fro the right pedal until its sorted

so what should the figures be normally then? I'm also getting a code 34 (det sensor circuit) on the ECU, but no MIL light on the dash though.

 

Can the Nissan consult tool adjust the fuelling too?

 

Most of the time I'm well under 3k RPM though, and being an automagic, it's harder to want to floor it, especially in this weather :)

well on boost it should be around the 11s coming on boost 14s should be fine 17 is very lean though, i doubt you could change fueling with a conzult cable youd need a chipped ecu for that, if your det sensors triggering the ecu might pull the fuel or timing so id get the det sensor checked out tbh

I think the sensor itself is fine, I didn't have the fault code prior to the turbos being changed, so perhaps it's a loose connection or something.

 

If you're suggesting a remap, it's probably the route I'll go. Going to change the fuel filter this week as it's a quick and easy job (for the mechanics at my works :D) and save up for a proper setup with proven dyno printouts.

 

I'm also looking at an AVC-R, but are those a bit fiddly to install on the Z?

im going down the same route but ill have to get the manual conversion done first, if you have bigger tubs a remap would make best use out of them although your injectors will max out at 17psi so if you want over 350ish youll need injectors and i think youll struggle to map it with an auto box ( it just wants to kickdown all the time)

 

might be worth checking your fuel pressure could be your pump on the way out

oh and yea boost controllers are a pain if you havnt done one before

Yeah, it'll have a manual box eventually, but because the turbo gave up, it became a priority to sort that out. It's just a case of putting the money together and getting it, but theres lots of other niggly problems to do too :(

tbh im thinking of selling my manual conversion i wanted to go down the same route as you but ive grown to like the auto box and im thinking of leaving it alone now lol also ive got a hankering for a 33 gtr lol, so if your in the market i may have one for sale brand new clutch and all

I'll be in the hunt probs around March time to be honest with you :( Once Christmas is over, I'll start to put the money aside for the conversion. My ex BF used to have an R33 GT-R, but I loved the Z more than it :)

I'm also getting a code 34 (det sensor circuit) on the ECU, but no MIL light.

 

No engine fault or mil light will occur on your zed as it the more basic OBC 1 and as such has no ability to report back a real time fault except in the error memory.

 

If the det sensor code is an active code and not just an old one that is no longer active then not only will boost be limited but the ignition timing will be retarded, this means no amount if tuning / rolling roads will have the engine running correctly, the det sensor fault could be cable, connections, or mixed up cable connectors between the det sensor and the variable timing solenoid.

 

If you're suggesting a remap, it's probably the route I'll go.

Going to change the fuel filter this week as it's a quick and easy job (for the mechanics at my works :D) and save up for a proper setup with proven dyno printouts.

 

I'm also looking at an AVC-R, but are those a bit fiddly to install on the Z?

 

You need a full set up check and rectify before any more rolling road time, and a remap will not cure faults such as det sensor circuit issues or boost leaks, only once its set up correctly should you make any decision about more tuning work.

 

Jeff TT

If it is still smoking, could it be burning oil off in the elbow/exhaust from your old kafuffled turbo?

How do they measure the air/fuel ratio if you don't have a gauge fitted? What do the values mean? When you say it was 17 at idle, does that mean it using a ratio of 17 parts of air to 1 part fuel 17:1?

How do they measure the air/fuel ratio if you don't have a gauge fitted? What do the values mean? When you say it was 17 at idle, does that mean it using a ratio of 17 parts of air to 1 part fuel 17:1?

 

to measure the afr they put a rod with a wideband o2 sensor bolted to it ( sort of looks like a small exhaust pipe about an inch around ) and thats linked to the dyno's computer.

 

the computer then takes a reading from the sensor every 100rpm or so which would then be use to plot a graph.

 

yes when people say its 17s or 10s they are taking about a 17:1 or 10:1 afr idealy on a turbo car you want it to be around the 11:1 mark when its on boost

to measure the afr they put a rod with a wideband o2 sensor bolted to it ( sort of looks like a small exhaust pipe about an inch around ) and thats linked to the dyno's computer.

 

the computer then takes a reading from the sensor every 100rpm or so which would then be use to plot a graph.

 

yes when people say its 17s or 10s they are taking about a 17:1 or 10:1 afr idealy on a turbo car you want it to be around the 11:1 mark when its on boost

 

Nice one mate, thanks for clearing that up for me!

Mate you need to get this on a conzult and diagnosed and certainly your timing checked to be sure!

 

The ONLY connection between your fault and those turbo's can be something altered/messed with/broken while they were fitting the turbo's.

They are such a a small upgrade compared to stock, nothing needs changing in any way once fitted.

smithy

Nice one mate, thanks for clearing that up for me!

 

no probs mate

I did go for a little drive today, and for some reason the standard boost gauge didn't seem to go into positive boost. Power seemed ok in negative boost driving normally (auto lol) and seemed a little hesitant when I hit the motorway. Would that suggest the wastegates are closed or something?

im not 100% but if its got standard boost solenoids the ecu may be able to cut the boost if it senses a prob and goes into safe mode although im not certain of this, again i wonder if it could be down to your det sensor code?

oh and if the wastegates stay closed the boost will just keep building they control boost by opening and venting exhaust gas back into the exhaust pipe thus slowing the exhaust turbine down, think of it like a trap door on the side of the turbo

Maybe they have popped the vaccum pipes that go to the recircs backwards so they are constantly open thus not allowing you too boost easy done.....

who did the turbo swap?

 

Sounds like a lot of basic things are wrong, so suggest you start with a boost leak test & conzult as others have mentioned