Sorry they are portrait and a photo of a bit of paper but you can read them. It is running rich as hell? Dead O2 sensor/s?

Power curve looks ok, but the fuelling is silly. Once you sort the AFR out you'd probably unlock quite a bit more power too

 

I'd say you have a boost leak so not all the metered air is making it to the engine, that or it's a real poor tune.

 

What mods do you have?

PS on most dyno's you'll get 350-370 with 14psi of boost on stock turbo's and a generic chip

Front to back. Twin Apexi filters with a Selin dual MAF. Standard Smics with silicon and z1 Hardpipes. 14/15psi through a hks evc5 ebc. A eprom chip from zedworld fitted during a zedworld service which set the timing right and the engine is in good nick well serviced. Turbo back twin 3 inch Janspeed exhaust with decat. No dump valves, standard recircs and it has auto turbos. fairly standard. I don't think there is a boost leak or at least not an obvious one but I'm Gona re jiggy all my Hardpipes anyway they have a mish mash of clips atm so for aesthetics if nothing else.

 

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Front to back. Twin Apexi filters with a Selin dual MAF. Standard Smics with silicon and z1 Hardpipes. 14/15psi through a hks evc5 ebc. A eprom chip from zedworld fitted during a zedworld service which set the timing right and the engine is in good nick well serviced. Turbo back twin 3 inch Janspeed exhaust with decat. No dump valves, standard recircs and it has auto turbos. fairly standard. I don't think there is a boost leak or at least not an obvious one but I'm Gona re jiggy all my Hardpipes anyway they have a mish mash of clips atm so for aesthetics if nothing else.

do a boost leak test if you can, be cautious though, if you find and fix one chances are you'll need to adjust the boost level on your controller

I don't have the proper tester, I will reposition the Hardpipes and have a poke around, you would hear a leak wouldn't you? I hope it's not the Selin dual MAF translator? It shouldn't be, any chance it's the 02 sensors. I want to get a proper ecu and remap done what what do you recommend?

is that not dangeroulys lean in the midrange? and the fueling curve doesn't match the raise in boost? I use question marks because im learning this stuff so they are much questions as observations.

I don't have the proper tester, I will reposition the Hardpipes and have a poke around, you would hear a leak wouldn't you? I hope it's not the Selin dual MAF translator? It shouldn't be, any chance it's the 02 sensors. I want to get a proper ecu and remap done what what do you recommend?

 

I got one you can borrow. You will need to use a compressor or somthing tho. Are you happy with the result?

Bolt I read it as air to fuel ratio, so a low number is not a lot of air for the fuel, rich in the midrange. And it sounds like you are underfire on overrun. Thanks Paul I could pop round we could test it then zed about a bit. If you didn't know it was rich you couldn't tell really it drives sweet and pulls well so I am quite happy, it had 280 HP twenty years ago and has 320 now so it's aged well. I'll get the other 50 soon.

Bolt I read it as air to fuel ratio, so a low number is not a lot of air for the fuel, rich in the midrange. And it sounds like you are underfire on overrun. Thanks Paul I could pop round we could test it then zed about a bit. If you didn't know it was rich you couldn't tell really it drives sweet and pulls well so I am quite happy, it had 280 HP twenty years ago and has 320 now so it's aged well. I'll get the other 50 soon.

 

ahh ok that makes sense, thankyou for clarifying. that make sit easier to understand whats going on, it would be cool if noz or someone did a quick thread to show how these graphs work and what is optimal.

I know, I think it's optimal to have all the lines stay on the page! Lol

basic rule for AFR is you want it around 14.7:1 at idle/cruising, but around 11.5:1 - 12:1 on boost.

 

You can play around with it a bit, eg richen it at high revs to provide a cooling effect, run even leaner on cruise for better mpg etc

I don't have the proper tester, I will reposition the Hardpipes and have a poke around, you would hear a leak wouldn't you? I hope it's not the Selin dual MAF translator? It shouldn't be, any chance it's the 02 sensors. I want to get a proper ecu and remap done what what do you recommend?

 

Have you got the Selin Translator set up correctly? You need to have it set to 'Add' if the chip is written for a single intake, and you're using 2 MAFs (not a single plus dummy MAF). What's the spec of the chip?

 

It won't be your O2 sensors, there isn't lambda feedback on WOT.

 

The OEM ECU is fine for the majority of people as it can be fully remapped as it is. It's only when you're looking for motorsport settings (full-throttle flat shifting, anti-lag etc) or improved resolution & knock control that you need to look at aftermarket solutions. I've personally run 1000cc injectors using a stock Nissan ECU on a 200SX, it was just like stock.

Thats running very rich, AFR of 10:1 pretty much through the rev range, its deffo got more to give. Wouldnt say you have a boost leak either, looks like boost builds nicely and is pretty consistant but your pretty much on the limit of the Auto turbos at 15psi, more likely that its a very very safe map.

I will scrape the snow off and check but the instructions for the Selin thing were fairly to the point and I think it said "two settings one will kill your car use add." But I may have been an idiot and got it wrong. The chip, I dropped it in at zedworld not long after I got it for a load of stuff but basically wanted a good look over and the chip for added boost using boost jets, so it's the zedworld eprom. I have since had it ebc-d and dynod. So who should I see about getting it mapped???

how many MAF's do you have, and did you have split pipework before fitting the Selin.

 

If you did, your chip is probably doubling the MAF voltage aready, and what you need to do is set the Selin to average between the two.

It had one Apexi and MAF on the end of the t piece. Now it has two apexis and mafs on two 90 degree silicon elbows. Should I just try average mode???

no, if you switched to 2 MAFs and the Selin at the same time then 'add' is the correct setting.

 

Best get your setup checked out by either John Dixon or Noz on here so they can check the chip out at the same time and make any teaks if needs be

Thats running very rich, AFR of 10:1 pretty much through the rev range, its deffo got more to give. Wouldnt say you have a boost leak either, looks like boost builds nicely and is pretty consistant but your pretty much on the limit of the Auto turbos at 15psi, more likely that its a very very safe map.

 

Auto turbos run to a lot more than 15 psi if you want them to. It is far from a "safe map", running that rich is detrimental to engine health.

Auto turbos run to a lot more than 15 psi if you want them to. It is far from a "safe map", running that rich is detrimental to engine health.

 

without wanting to get into the same old discussion of zed turbos, but its pretty much accepted that they become inefficient over 16.5psi, so while they will go higher, there is almost no point.

 

I didnt just say safe map, i said very very safe in that its been set to over fuel to prevent det, agreed that if that is the case that engine wont be far off bore wash

without wanting to get into the same old discussion of zed turbos, but its pretty much accepted that they become inefficient over 16.5psi, so while they will go higher, there is almost no point.

 

I didnt just say safe map, i said very very safe in that its been set to over fuel to prevent det, agreed that if that is the case that engine wont be far off bore wash

 

See here for a compressor map for actual efficiency islands:

 

http://www.300zx.co.uk/forums/showthread.php?161833-What-s-a-sensible-boost-for-a-300zx-on-stock-engine&p=1703156&viewfull=1#post1703156

 

There is a lot of evidence, on here and from results all over the world that they work just fine at higher boosts than 16.5 psi. The compressor map should be accepted as the be-all & end-all really, and there is lots of room for manoeuvre above & beyond what is "accepted".

 

Sorry, I'm not sure what the difference between "safe map" and "very very safe map" is, but I'm just trying to point out to the owner & OP that it isn't a "safe map" at all. Overfueling doesn't prevent det, its purpose is for additional cylinder cooling in applications that might require it, such as prolonged track use. Correct timing & fuel octane is what prevents knock. All you're going to get with an overly-rich mixture is the promotion of pre-ignition due to all the carbon build up and subsequent hot-spots, plus an increase in compression ratio over time leading to an increase in the chance of actual detonation.

 

HTH :)

Oh dear, well I've driven quite a lot with it like that I will get it sorted immediately it worries me I did 120 track miles like that. I heard my Capri detonate it was like a gentle dry cough noise with a shudder rev wobble and shit out the exhaust but that was fatal engine detonation. My knock sensor is bypassed which makes things worse. Noz will you remap it if I bring it down to Leicester?

The full works rolling road remap???

Engine detonation (aka knock, pinging, pinking etc) sounds like an empty bag of crisps being crumpled. Or some marbles rattling around in a metal container. High-pitched crackling noise.

 

Full works dyno remap, not a problem. Just let me know as & when :)

 

Have a read through my section mate:

 

http://www.300zx.co.uk/forums/forumdisplay.php?170-Turbonoz

Don't think I have ever heard that is that at full power. I just heard the sound of a 2.8 turbo technics Capri spitting out it's piston rings then.

I think it will be an 8 bit ecu with a zedworld eprom and the £250 remap looks right, don't suppose I need the nistune thing. How long do you need the car I work random shift runs but I'm free this week? Road test in the snow permitting.

Sorry read your other post 2 days that's fine, would you be able to have it a bit longer I may have to drop it in go to work for a bit then come back.