Compressor Maps

[Bean]

Stewart - You and Keebs got me all fired up again on stand alones again, so I've contacted Nick Cota and I'm making arrangements to get my set up back. I also contacted Jason Russell that currently has my system (US VEMS distributor), so I'm going to get it updated with the latest software and likely get a few add ons.

I like the idea of the SD data card logging capability, but I would also like to pony up for an unterminated harness to install on the car, Bosch motorsports coil, seimens injectors, egt t-couple, air temp sensors, and the WB02 sensor...

Ideally Id like to get everything I need for an install, and then see if I can even afford the "nice to haves". I'll weight that with the convenience of having it there now so it can be upgraded properly.

Keebs and Stewart - any advice on what I should make sure to get?

Stewart - I saw the exhaust vacuum device and knew right away I'd need one of those too!

Keebs - I've had buddies comment on how hard cold start tuning and drivability can be - but never have tuned anything myself yet so it's all third hand info. Up until now I was chaulking it up to our stupid cold winters, and trying to get drivability out of a car at -40C. Thankfully those days are over for my Peugeots - so it will basically just be fair weather tuning.

Rabin

[keebs]

Cant see the page. VEMS is pretty simple, but some things could be made better. My biggest gripe is the tuning software doesn't quite fit my laptops screen right, so its pretty good overall.

[keebs]

Rabin, I would suggest a GM open element iat and GM closed element clt sensor, or any pair of sensors that use the same resistance curve for consistent readings. VEMS doesn't yet support the new lsu4.9 WB, but you can source one from a vw jetta or something for 50 dollars. A second map sensor for active baro correction would be nice. One thing you might want to start thinking about is a firewall grommet, or a fully sealed bulkhead connector of sorts.

For the cold weather you can pretty much guess the coolant curve, then adjust as it warms up. You can set cranking enrichment based on the warmup table. There's also a compensation table for iat/tps which comes with some base numbers that are probably correct. There's also a clt/map ignition table, and iat/map ignition table. I'm still waiting for winter here, but don't see it being and harder than tuning for summer.

[Bean]

I'm guessing this page: http://www.vems.us

Or maybe the euro site?

Rabin

[keebs]

That was probably it. Might want a flex fuel sensor too just for kicks.

[Stewart]

I wish someone could show me how.

I took the thing for a run today, Quick tune/auto tune mixture and, it feels and reads ok. 0.5 bar inlet pressure is feeling good.

I don't have any oil leaks or coolant leaks either.

If I set the ignition timing at the degrees I use for idle seems to be OK. Start Mixture has got me beaten, I admit!

Can I throw a thought out for start mixture to go 3 times injector idle pulse width??

[Bean]

Keebs - Do you have any pictures of your EGT sensor install in the manifold?

Hoping to make some time tonight to detail my list to complete the VEMS install on the car this winter - See what kind of budget I'm looking at.

With all the cool kids doing stand alones I've got to get up to speed asap as well.

Rabin

[keebs]

Stewart, it shouldn't take too much fuel when cranking start at 0 and work up a few percent at a time. Your VE table is only multiplied by cell. So if hot idle is 60ve at whatever map/rpm at 2ms pw, and during cranking its 80ve with 3x multiplier thats a lot of fuel.

Rabin, I hope that pic is clear enough. I drilled there for ease of service, and to keep the leads from melting.

[Stewart]

Thankyou Keebs,

So, enter idle number for injector hot idle, at 0 rpm pre start condition and add 30% to it. ( 60 VE idle to 80 VE crank is 30% increase in VE for crank speed.)

Is that the technique ?

It makes sense to me but, I am a proven nutter!

[keebs]

Here's a pic I pulled off google. You can see the cells below 1500rpm are all similar. The example I gave was to depict an over fueling condition at start up. If you send me a config file I would be more than happy to help.

[Stewart]

Thanks. This the fuel table Manifold Gauge Pressure/RPM.

I'm thinking I should try a TPS to rpm with barometric correction.

There is a choice to. It seems to be a clearer type of table to work with.

[keebs]

Map vs rpm is said to be a better calculation. Does LINK require a 0rpm bin. If not I would rescale for 700-idle-1300-... no sense having all those "unused" cells. Let me see if I can download the tuning software to get a better grasp on how it works

[keebs]

I downloaded the LINK software a few minutes ago. It's laid out a little more difficult than VEMS, but has all the same thingamajigs and doodads. I wish i could be of more help, these things aren't easy to discuss through print. If you download VEMStune I'll send a config file so you at least have something to compare against.

[Stewart]

Thanks man. I think I have got the system pretty well understood now after your suggestion of using hot idle pulse at crank position.

0 rpm, 0 tps , 80% VE or so is what got me thinking. Of course, Of course! It's nice to share some thoughts and knowledge, thankyou.

I came upon the idea of using the Auto Tune in TPS to RPM and set what mixture ratio I want at X amount of throttle. It made sense for me then.

I idle at 12.5 and want just off idle to be the same. Part idle at 14.5 stoic. and anything after 30% TPS go for 12.5. Let the MGP and RPM fuel graph contend with itself ! I tried it at idle, setting different loads and it is an order of magnitude sweeter! i'll come up with a better explanation once the old head gets around it all. The engine is certainly sounding and running as I had hoped for, so far. Quiet and quick.

[keebs]

Excellent, glad we didn't get lost in translation. If you're using full sequential injection idle and cruise can be pretty lean. 14-15 at idle with a rich "hill" below for idle stability and up to 17 for low load cruise. Are you talking about a blended table where it switches from map/rpm to tps/rpm at 30%? If yes, it's a good strategy. But just for fun let's say were going down the highway 30% tps -40kpa 2500rpm (I know bear with me) the grade gets steep and we're feeling lazy so we hold throttle steady. As we climb map rises into boost (-40 to 70kpa) and rpm stays constant. So since rpm and tps stayed constant (stayed in one load cell) the ecu had to compensate fuel by WBO2 for a 1.1 bar pressure change. Just a little food for thought.

[Stewart]

This table is for quick tune set TPS to RPM to air fuel ratio.

Does this make sense to set up initial af then a tweek on the dyne?

So the fuel is MGP to RPM with the cells indicating the percentage of open time of the injector master pulse width. It is starting to gell for me now with your help, thanks.

[keebs]

The pics wont enlarge for me but if I understand right tps/rpm is your lambda target table and map/rpm is the fuel. If that's the case +1 for link. The maps make more sense now, didn't realize they were showing inj pw. What kind of injectors are you using?

[Stewart]

Yep that's the idea. Tune to what I want within what I think is tps/rpm af I want, then tweek the cells if need be in those stationary throttle inlet pressure changes. Should go close.

As a by product of this, did you know The Innovate system can be manipulated to read real mixture and modify that reading to a Lambda number to send to an ECU expecting a volt between 0 and 1. Thus if a low voltage is sent indicating Lean Lambda condition when in fact the ecu is being tricked to richen within it's ranges. I'm not going down this path with this engine but will consider the options for the V8 to run closed loop mixture control. Some ecus will only go closed loop lambda but the dither volts can be altered to give more or less gas if being lied to by an Innovate to get an ideal reading. I notice one I checked out was built with a wide band controller in it. That is cool. The ECU for the V8 has data logging and knock control in closed loop but not wide band mixture stuff, but that is OK now we have got a lot more knowledge here about setting it all up! I reckon closed loop wide band would be so good on a turbo but the 4 wire sensors need to be recalibrated every few months, I guess that's why suppliers don't go down that path much.

[keebs]

I ran the innovate WB feeding the stock ecu before going stand alone. Closed loop afr is best left alone. A better solution would be a map or tps based switch to kill the o2 ecu input and force open loop which is easily tuned with fuel pressure. Now wideband sensors do have a long lifetime (50-100,000 miles), and have been used by German OEM for many years. For some reason the innovate controller burns them up. The new lsu4.9 sensor has more data points and doesn't use free air calibration. It's not very well supported yet, but is soon to be the new standard.

[Stewart]

Yes, the old L Jetronic ECUs could run with or without a Lambda sensor input in the '80's. and any tweeking did not make much difference. The Link will do closed lambda to 100 kpa MAP but the old cylinder head design and my valve timing do not like it! The machine is idling at 920rpm at 12.5 AF tonight, smoothly. I must say the VE way of expecting what sort of fuel delivery pulse is working for me. I'll be back in touch in a day or so,

thak you Keebs and Rabin.

[keebs]

I looked through the software again, and it's interesting to say the least. Under closed loop control does it only allow stoich? I saw you can configure its shutoff points based on map/rpm, but I'm mildly confused about how it works. Is the lambda target table only used for auto tune? I might have to buy one of these ecu's just to tinker, maybe put it on my tractor or something.

[Bean]

I've waited 20+ years to have this level of technical discussions about tuning our cars - so this thread is truly epic for me.

I'm now itching to get my VEMS so that I can apply the ideas discussed myself to see the results first hand.

Thanks for sharing the discussion on the forum as it really does become a valuable resource for others.

Rabin

[Stewart]

I drove her to work today after letting auto tune settle the idle etc. This afternoon I'll do the auto tune tps to rpm which will work in the mgp rpm fuel table to af ratios in the AF table. It is so close now! It is only pushing into 2 or 3 psi and it is smooth and grunty. 920 rpm idle with a 280 cam and it pulls away at very low revs with no jerks or misfires. Keebs, what I did with the afr targets was to set 12.5 at 0 to 100 % tps under 1500, then for under 20% 13 to 14.5 depending on rpm and over 20% 13 to 12.5, , we'll see what transpires after work today. I'm lucky enough to be able to drive almost on see level on a road on Bramble Bay here in Queensland Australia, so the barometric compensation should be spot too. Very happy so far. It certainly has more low down grunt than the previous set up.

[Stewart]

Well Chaps, that worked pretty well. It must take thousands of hours to get an accurate fuel and ignition map. It's taken me about 4 times that!

My focus is on smooth delivery of torque, right off idle and, with auto tune and your help, we are close to a victory! Gee it sounds good at 3000rpm at 100 kph. That Peugeot growl of old.

So, from here I've noticed a couple of things. I don't have much inlet pressure but my goodness it is a smooth and cool sounding engine. Very quiet in the exhaust and the baby T25G is whistling happily.

Keebs about injector size, they are a Siemens unit of 660 cc per hour or so. I can get the number for you in the daylight! I pulse them once a cycle at 2.5 bar constant rail pressure.

I am enjoying this too, Rabin. How about you weigh an inlet and exhaust valve assembly and a rocker arm so we can get started on some new valve springs? Hooray, Big Cheers and Good Luck for us!

[keebs]

Sweet, I hear you on the fuel map I spent a few hundred miles getting mine smooth. No need to get the numbers off the injectors, I have the same ones. These injectors were designed for ULEV vehicles, they can handle 6 bar without trouble. Bump it up to 3 bar or more, it might run better with less fuel.