Turbo Bug map structures and stuff

[bazibbo]

I've been beavering away on my beetle and have seen the light, dumped my carb and gone full fuel injected



Its very early days, I’ve only just got things up and running, and only run for a few tentative miles, using a closed loop and Franks great writeup about map building.


I'm having a few comments from peeps on the VW forums, that I'm a bit wrong in my initial setup as I'm trying to do all my boost corrections on the single spark map, without any corrections elsewhere. - this is my main concern at the mo.

A few details.

DTA S40 on a T3 turboed 1914 bug with a modefied EFI from a mexican beetle, running MAP, not TPS, and at this moment I'm hardly running any boost, I will aim to be between 6 and 10 psi.

Here's a few pics to show you

Spark map, where I've attempted to sort all my boost related stuff.



Manifold pressure comp, that I've left zeroed, but I'm wondering if I should be using this.



Lambda setup, probably needs a bit of fine tuning, but it appears to work.




AFR target map.... hopefully middle of the road. Aircooled dubs like to be a bit richer I'm told.




General engine settings. I think these are OK, not changed from initial setup.




On the few miles I've done, I did appear to be hitting my AFR targets (once I remembered to give more than 20% fuel increase permissions) and was beginning to create a build a fuel corrections map. I was getting a slight detonation issue at low revs / low throttle openings, but I should be able to iron that out.

I'm going to be running this setup for now, so I'm not after changing throttle bodies and so on... I'm all spent up


I think the big question is, should I modefy the spark map from 110 to 180 to match what happens at 100 and then change my manifold pressure compensaton? Or just carry on as I am?

Any input much appreciated.

thanks, Barrie

[stevieturbo]

What you are doing with the ignition timing map is 100% correct and the best way to do it. Ignore anyone who tells you otherwise.

Whilst theory will dictate to reduce fuel as air temp rises, on a boosted engine I would not do this. The last thing you want is high air temps due to boost leaning mixtures out.
I'm not saying add fuel, but I wouldnt lean it out either.

And at relatively low boost 12:1 AFR should be ok, although if it's a new build I'd always aim a bit richer for safety until timing etc is optimised, then you can start to lean things out a little.

[bazibbo]

Ta Stevie

I'll zero the reductions on the air temp compensations and maybe richer the boosted AFRs a bit. I've got 50 miles or so to do tomorrow. Just gentle back roads stuff.

There's a few bits of low throttle pinking to sort too.

I'll write it up tomorrow.

One question I've got, if anyone's around. Setting the sample rate of the lambda, this do I judge the 'cycling' effect. Should I be looking at a single cell somewhere or watching for the afr reading to stop fluctuating on a steady throttle?

[stevieturbo]

I dont see anything in your ignition map that would lead it to pink. Have you confirmed timing with a timing light ?

As for closed loop....there are various threads on this on the forum. However, For a new build and a new map, I would be leaving closed loop off until you have a half decent base map to start with.
With the laptop attached, there is the PC logging of lambda in each cell as you drive, which can then be used to apply corrections.

Sample rate will vary on setup and type of wideband you are using though. it can be tricky to get everything working correctly, even more so when your fuel map isnt pretty close already.
IMO a sample rate of 25 times per second is too high though. Most widebands wont even read that fast.

I would also lose those mikalor clamps. They are big and bulky and rarely seal properly. A decent stainless Jubilee clip will be better.

[bazibbo]

I've revisited the timing and updated the sensor position by 2 degrees... I'll keep checking this, an unsteady throttle and a short laptop lead means its a 2 man job.


Current sample rate is down to 15 and its a bit less erattic now.

Yes those clamps are attrocious, I've already removed two of them... they overpromiced and underdelivered.

appreciated, thanks.