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Compressor Maps


Stewart

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Well, at last the engine is running, and not too bad either. She is idling at 13.2 mixture or so at 17 deg advance and at 950 rpm. The surprising bit is the exhaust temp at idle at the turbine inlet is 107 deg C!!!!! I can also hear a nice little whistle which I thought was the 120 amp alternator but no, it is the little T25G happilly spinning away. I found a diverter valve from an XN6 which were electric over vacuum so I've used that as the Blow off valve. Still a work in progress and I think this manifold and turbo is going to mean a lot of retuning! Sounds OK in the shed.

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Yep 107 C!!!! That's just idling in the shed. Before I hooked up the innovate and reset the mixture, the exhaust went to 400 C. Amazingly the change in exhaust manifold and turbo has changed the idle mixture and ignition requirements. Dynosim has helped a lot. I have a water to air IC set up running engine coolant through it. My aim is to get great torque and flexibility by maintaining 50 to 60 deg C in the inlet. Also the IC should help maintain engine coolant temp on cruise. I noted last night inlet at compressor wheel ( no air cleaner fitted) was 70 C as the engine fan ran and, the inlet manifold temp sat at 60, so all good so far. Working on fitting a decent air filter system so it's close to coming off stands and driving again.

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They are pretty good aren't they? I think my 107 C in the exhaust was due to the cables not pushed in properly in the dmm and giving a low reading. The engine sits at mid 200's now and sounds fine. I had a moment of terror Wednesday night when I gave her a big rev, ( which to me the system sounded fantastic) and the engine breather hose I'd rigged up vomited oil over the hot engine. Too close for me as my garage is part of my house. I found my flaw in my breather system, which became obvious to me after watching a 1/2 liter of oil go up in smoke on a hot engine.

I had the vent hose at the rear of the valve cover. the engine leans back at an angle to meet the gearbox and I had the car on stands at the front so the engine is leaning back a bit. Something like a light bulb above the head in a cartoon flashed and I'd realised what I'd done wrong.

When I was a lad I did some work experience with a plumber. He said to me , " Son, there is not much to this plumbing trade really. Just remember water doesn't run uphill and pay day is Friday".

I had the breather hose on the lowest part of the valve cover, didn't I! Oil had to flow out of it. Sorted that yesterday by changing the hoses around and hey presto a nice almost zero pressure breather hose is venting a tiny amount of engine vapour. Yippee! I'll be venting that hose into a safe catch can as far from that exhaust as I can go! En avant.

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Catch can is looking good now and I reckon instead of venting a small line into the exhaust I'll try to fit a hose under the venturi in the air horn.

The engine sounds just fine. I wish you men could hear it in person. Nice noise.

Next week I'll try to join the dump pipe to the machines' exhaust and retune it.

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I like the idea of venting into the exhaust - I'll have to see what's the best way to that since I'd still want to use my ProVent to pull oil vapour out of the PCV air...

Stewart - any chancce you have access to a smart phone? Usually the easiest way to video and upload to YouTube, or you can upload to the site if you can upload to my ftp server. (I can send directions if you want)

Rabin

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I got the closed loop idle control working yesterday. some fine tuning on mixture to go but it ain't bad. Nutted out a vacuum source for the can and will use a tiny one way valve in the hose. Aaaandd the electric BOV works beautifully. It turns on with TPS at less than 1%, below 40 kpa on MAP and uses manifold vacuum to lift off the seat once the solenoid clicks on. And makes almost no noise.

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Just been thinkin' and sypherin' agin, Uncle Jed! I didn't mention the Dynosim ignition prediction is working so far for this initial tune . Engine sits between 13 and 14 to 1 air fuel with the ignition graph using the base prediction for atmo timing. At idle I use 22.5 at 1000 rpm, sim prediction is 22.4 at atmo so we have a pretty sweet deal going on so far with this. As in previous post I set up the closed loop idle and rejigged timing to get it smooth irrespective of what the Sim suggested, ( because I didn't even think of using the figures to start with at idle condition) and here we have a perfect match up. I'm building a lot of faith in the sim now I've got to understand the complexity of input data. I think if we discuss what are good base points for an engine build on the N9T we will get some hard true data for a stand alone pre tune map on ignition. Should speed things up prior to dyno tune runs. Nothing worse hearing all your hard engine work going up in smoke with a dyno operator letting the engine detonate on the rollers! ( Been there before!)

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Hey Rabin,

I'll try to get the exhaust connected this week so I can drive it and tune the mixture. I can get a phone to video some of the goings on yes.

The venting to exhaust can be done using a reed valve we used to have on exhausts for air injection. The zdj engines had them. I also have found a metal pcv valve off a D21 nissan which could also be mounted on a tube into the exhaust if that helps. Most of todays Peugeots are running electric vent valves for crank case venting just before the turbo. Most have a can too but some of the cheaper models just run an electric vent to the air inlet.

Moroso are Kings at this stuff. We can pick up hints from them I reckon.

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Learned something new with using the exhaust to pull a vacuum in the crank case... :)

When I was looking at electric vacuum pumps for my TD I ran across some pumps that were designed only to create vacuum in the crank case - I like this idea quite a lot. Thanks Keebs and Stewart!

Rabin

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Exhaust wont pull much vac, but it is fairly consistent with few failure points. When we get into pumps caution should be used as too much pull dries out wrist pins. 10" of vac is near tops for reliability on a street car, but wont make much hp gain. At this point it takes about as much power to run the pump as you've gained. If an electric pump is used you may get the same results depending on how much load is exerted on the alternator. So if we end up not being able to make more power at least the exhaust scavenger will keep oil contamination down without costing anything. Or we could all go dry sump which makes excellent vac and lets us put the oil wherever it's needed.

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Yeah, I reckon some small vacuum to the breather is very important to help dry out the crank case during warm up. Oil can get very contaminated in low temps or on short runs where it doesn't get hot enough to get rid of blowby contamination . You may have noticed what appeared to be signs of ice cream in engine oil which may have been a blown head gasket but coolant level is not dropping. It is due to a blocked breather and usually poor vac supply due to pcv blocked or pcv hose leaking.

On a lighter note the closed loop idle is fantastic on the new layout. start car and the engine just sits and idles right through warm up to 95 C engine fan. That is a real triumph that one. 280 deg cam sits from cold to hot from 1100 to 950rpm. What a relief!

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Cold start tuning is always the hardest to get right - Can't wait for your report on how this beast drives!

The milkshake in the oil cap is always an issure for me in winter as it's so cold and the engine never gets up to full operating temp. I try to get on a good drive every week that ensures oil temp gets hot enough, but having a better pcv vacuum set up should help that out some.

Rabin

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Glad to hear it's one step closer, a smooth idle is not a small task. Setting PID can be like threading a needle in the dark.

Rabin, you would be surprised how easy it is to set the cold cranking/warm up fuel curves. To be honest one of the most time consuming parts can be getting accel enrichments perfect.

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Well she is on the road. Very flexible. I think my Jethro Bodine BOV is a failure as I think it is bypassing heavily after 10 kpa boost. Will test tomorrow and block off for the time being. ( It just ain't fast enough). I entered the new ignition numbers from dynosim and the off boost flexibility is awesome. Funnily the off boost mixture is as good as prior t3 turbo set up . Once I find where my air flow is going, I can do the auto tune on the boost mixture. The closed loop idle also lets the engine gently come back to idle where you can adjust the reduction and increase rate of iac valve pulses. Not bad at all !

Oh and Rabin, I have entered the 21st century today and have a smart phone in my possession. I was given it. Whether it travels on my person will be a different matter but I may now get some interesting stuff on clips to look at.

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Yep! All good now. 0.5 bar feels fine for now. Engine has a nice growl to it and spools evenly and smoothly. Next step is to fine tune from here and go to 10 or 12 psi after that, altough I think that may be too much. It is already pretty close to what I wanted.

My Link G3 has a self tune or auto tune function for mixture which has turned out to be the best thing about the whole job. It will self tune in parameters you preset against an air fuel table and wideband.

Do any ecu's in your part of the world have this for smaller engines like ours? When starting from scratch this has got to be the best thing for a map!.

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