Power graph, Dous this look right?

Can someone shed some light on whats going on here please? This is a printout of my mates 200sx s14. Now im not to clued up on this but dous this graph look ok or look like somethings wrong? As it look a little all over the place?

Well I'm no expert but that looks rubbish, pretty sure it should be a fairly smooth line.

Yup that's what I thought, looks abit all over the place?

This is a graph of his boost aswell. & they've turned around to him & said its a good map??? Id beg to differ  

That boost line line is bad, looks like a cardiograph

Very bad mapping imo, & for them to turn around & say its good?? Are they on crack? lol

daves the best guy to answer this but I would say at a guess that he has got fuelling / ignition probs i.e a bad misfire.

would not be happy running with that as could result in big engine troubles

He didn't get an AFR print out either so god only knows what fueling is like as he's not running a wideband. But your prob right with an ignition fault, ive told him not to drive it till he has diagnosed the problem

Apologies guys, but I've only just noticed this thread  

To me the graph doesn't look great. First, I've seen a car's torque/HP figures begin to decrease a little at high RPMs, especially if you're running a smallish turbo that spools very quickly and begins to run out-of-puff at higher RPMs. However, looking at the boost curve, it appears that full boost isn't reached until around 4500 RPM. I've seen fairly large turbos (e.g. 3071Rs with the smaller 0.64 housing) reach maximum boost before this, so it can't really explain the drop-off at high RPMs unless there is some form of boost leak or fuelling/timing problems. Also, I'd be a little concerned by the spike in torque/HP at around 4250 RPM. It almost looks like the ECU has detected knock and put the car on to a "safe" map, causing an immediate drop in torque/HP. I also don't like the jittery figures at higher RPMs, which again looks like poor mapping (perhaps as a result of being defaulted to a "safe" map - see above). Obviously, the best diagnosis can only be reached if all the data is at hand, particularly A/F ratios and some ECU housekeeping data. Still, I'd not be overly happy with these graphs, and the top of my list would be checking for boost leaks and/or ridiculous A/F ratios.

Cheers.
Dave

PS - I can't see from the second pic, but what is the maximum boost reached? The flutter at high boost looks like the wastegate is struggling to regulate properly. Often there is some flutter, but the jittery motion on the rise phase may also point to something like a boost leak.

Cheers,
Dave

Its got a Tial external wastegate, that he bought form tuning developments who mapped it I know there is a lot of fake tial wastegates going round, but would of thought it would be legit from a tuner?

Ill tell him he needs to look into it & also look at if he has a timing issue

Cheers Dave

Yeah, I would imagine that a genuine tuner would use a proper Tial wastegate. It's just the non-smooth nature that makes me think the wastegate is either struggling (perhaps a too strong or weak spring inside the wastegate) or their is a boost leak (perhaps in the hoses that connect to the wastegate itself).

Either way, it may need some attention  
Cheers,
Dave

Its got a 8psi spring in & running a GFB electronic boost controller @ 1.1 bar, which I know arnt the best but the tuner set that up for him   But yep needs some attention.

Think his best bet will be to take it to someone reputable & get it diagnosed

if it was just a boost leak or actuator prob dave would it not just gradually tail off boost?

strikes me as though its trying to make boost but a misfire is holding it back hense the irratic curve at upper end of rev limit........similar to spark blow out or am i barking up the wrong tree lol

GTI-R US wrote:if it was just a boost leak or actuator prob dave would it not just gradually tail off boost?

strikes me as though its trying to make boost but a misfire is holding it back hense the irratic curve at upper end of rev limit........similar to spark blow out or am i barking up the wrong tree lol

I think there are a load of possible reasons that could contribute to the boost flutter. As Bob says, it could be a misfire, or perhaps even something as simple as a leaking BOV (perhaps not sealing properly - something I experienced on a Turbosmart Megasonic BOV with a worn spring which gave some jerky on-boost response).

The thing that worries me the most is the spike seen in the BHP/torque curves at 4250 RPM. I would love to see the A/F ratios for this run, as I'm still concerned that this may be a sign of the ECU switching to a knock map - particularly with the erratic fluctuations in everything (boost, torque, BHP) after this point.

I'd definitely be interested to hear the final diagnosis as there does seem to be an issue!
Cheers,
Dave

Ok cheers for the info Dave ill let him know & let you know the outcome