Turbo Dell tuning

GARRICK.CLARK · Posted: Mon Apr 13, 2015 12:26 pm Post subject:

Hi Clonebug.
I think with the comp being high that might be the case. After a run out the inlet manifolds don't seam that hot to the touch.
I've not checked IAT's. how would I do that, and what temp should they be.
I will need a water injection kit, They look complicated too.
1 nozzle
2 nozzles
best place for the nozzles, I'm not sure.
Is there a step by step on how to fit a water injection kit.

Cheers G.C

GARRICK.CLARK · Posted: Mon Apr 13, 2015 12:26 pm Post subject:

Double post

modok · Posted: Mon Apr 13, 2015 1:02 pm Post subject:

Usually 18 or 20 degrees is as low as you go with total advance. I think 15 is too low.
A simple turbo setup and with premium gasoline it probably will ping past 0.6 bar boost. You can run more sometimes but not on a sunny day. If you want to run 1 bar then you should run it on race gas or alky. Or at least run a mix of pump and race gas.

I would not advise water/alky spray when blowing through duals, as the distribution may be poor. The top side of your manifolding is too big to keep the water spray suspended, so it may load up in there.

clonebug · Posted: Mon Apr 13, 2015 8:18 pm Post subject:

GARRICK.CLARK · Posted: Tue Apr 14, 2015 12:36 pm Post subject:

Ok thanks CLonebug
I've got a forge bleed valve coming tomorrow and will set boost to a pressure that works just before pinging starts at WOT.
Did 40 mile tonight. On the way home 10 mile from home number 2 plug gave up. Limped home, dried it out, refitted it ,now its firing on 4 again .dont no why it did that.
The 60 mph cruise AFR is at 13.4. I'm trying to get it to 16.1.
160 air creates a hole
180 does not
Maybe a 170 air will lean out the cruise.
The 148 main has a WOT AFR of 13.9 so that's a little lean. I can drill those to 150.

GARRICK.CLARK · Posted: Fri Apr 17, 2015 10:34 am Post subject:

Hi guys.
Just when i thought it was good . It starts playing up. I can't get the low speed cruise AFR readings correct.
The cruise AFR is between 10 and 12.
As boost and revs climb the AFR goes leaner.
With the 140 main it will go to 15's under boost.
So that's from 10 up to 15
It should in theory be the other way round.
55 idle
140 main.
180 air.
33 pump.
So as it goes lean under boost it backfires.
I'm going to record the Fuel pressure under boost.

modok · Posted: Fri Apr 17, 2015 5:06 pm Post subject:

Don't run it lean!! If you think you need less than 150 main jets then you are mistaken.

Why is it rich?? could be overfilling the float bowls.

If there is too much overlapping between the idle and main systems try making the emulsion tube smaller diameter. #3 tube is 7mm instead of 7.3mm.

GARRICK.CLARK · Posted: Sat Apr 18, 2015 1:30 am Post subject:

Cheers modok.
This thing's driving me nuts.
The low speed cruise AFR is in the 10s depending on how much I press the throttle.
I've put my 160 airs back in. Still in the 10s but with a slight lean at the point when the mains start
I have some 148 mains which turn the plugs black.
It's like it needs more air to lean the low speed area.
It's been like this from the start.
I took the turbo emulsion tubes out and fitted the .2s thinking it would add some air to lean out the low end. It didn't. It's leaned out the top end.

GARRICK.CLARK · Posted: Sun Apr 19, 2015 5:01 am Post subject:

number 1. And number 2 aux vent have fuel dripping from them at idle. With a 6mm float height, 225 needle and seat with 3 psi.
I had it right once but believed what the Dell book says.

GARRICK.CLARK · Posted: Mon Apr 27, 2015 11:35 pm Post subject:

Am I running out of fuel.
13 AFR at idle
14.5 cruise
12 under boost rising to 15-16 then pop/bangs out of tail pipe
Thanks.

GARRICK.CLARK · Posted: Sat Jun 06, 2015 9:15 am Post subject:

Hi guys.
I have done some more work to this motor and have got it running better.
I had the slip joints on the exhaust welded up. So now there are no leaks. I have relocated the BOV. Unlocked the timing. Total advance is 24*.idle is 12*.
I have modified the Dell's by drilling a single hole in each butterfly to allow me to back off the idle speed adjusters so that the butterflies are completely closed and not allowing any progression holes to metre fuel at idle. I now have zero vac at the vac port on idle. My AFR is looking better. I put some 45 idle jets in adjusted for best lean idle. AFR idle is now 16-17 cold and once warm its at 13-1. 65-70 mph I'm seeing AFR at 15-16 depending on how much I back off the throttle. There is a lean hole before the mains come in. This must be due to the 160 air jets. My next step is to refit the 180 airs and retest it. I still can't do a WOT run . Half throttle gets me past half a bar boost. Then it starts pinging so I'm unsure if the 140 main jet is big enough. I changed the actuator for a weaker one to limit the boost but maybe the spring is still to strong.
Water injection is a month off so that should help a lot.
Single step tuning has helped a lot and writing it down for reference.
I have the cone filter on the end of the turbo. Moving that to a cold area should help as were it is now after a run out the filter gets warm from the heat being generated from the turbo.

DerrickfromNC1 · Posted: Sat Jun 06, 2015 4:46 pm Post subject:

Hi Garrick
Been following your thread closely and I'm beginning to think that if I'm not ready to go EFI then the best option is to go with a simple turbo prepped 600 holley in a pull-thru application, programmable ignition, and water injection setup. Seems like a lot of time and effort is spent trying to tune webers and dells to perform thru-out the entire rpm range and a lot people never get it right. Many who claim theirs are running good have never checked AFR and are just running overly rich. You've put in a lot of work up to this point and still can't run past half throttle.
I have a set of NOS 48 dells and I'm not sure I want to deal with all the mods, jet changes and experimentation necessary and still not have fuel management at 95% correct thru out.
I'll be following your future progress reports hoping that you can put together a road map for the rest of us to follow.

clonebug · Posted: Sat Jun 06, 2015 4:56 pm Post subject:

While I'm not familiar with draw through....they do have their own issues.

Those Dell 48's would be way too big for a blow through application in my mind due to the on/off affect of those large throttle plates.
I would think cruise would be tough to tune on them N/A or turboed.

There is nothing really easy with running a turbo. I fought mine with a single carb for 2 years. It always was a compromise.
Getting above 10 lbs. boost is quite a serious undertaking and you have to have good equipment to push that much boost.

You can build your own Water Injection system for about $200.00 in parts.
STF has a "Cooling Mist" WI setup for sale for $200.00 That is a good price and you can't build one for much less than that.
_________________

GARRICK.CLARK · Posted: Sun Jun 07, 2015 3:29 am Post subject:

Hi Derrick. Once I get it done ill post what exactly I have done to make it work. I wouldnt use a NOS set of 48 Dell's for a blow through there very big and being NOS are worth big bucks if not messed with.
One thing I have done but not mentioned yet is to modify the CB emulsion tubes by adding more holes to the off boost low speed cruise area of the E tube. Extra holes provide a leaner mix in that area of the rev range. Dave vizard talks about E tube tuning on you tube.
180 airs next.
Single changes only.

GARRICK.CLARK · Posted: Sun Jun 07, 2015 11:34 pm Post subject:

Ok. Did an N/A test yesterday to check AFR. Engine ran fine. No popping , pinging. AFR was Showing 10's. at WOT. Yes too rich, but at least I no it can go rich. Then refitted the turbo pipes and the mod rings. AFR at half bar boost and half throttle is In the 15 's creating lean back fires.
If I put in a larger main then the 140 I'm using. The lean under boost condition happens sooner.

modok · Posted: Mon Jun 08, 2015 1:12 am Post subject:

Misfires will make the sensor say lean. It's an oxygen sensor and it's sensing oxygen that didn't get burned.

But if you feel no misfires, and it reads lean, then it probably IS lean.

The vent size and "mod ring" size are jets too. IMO change those first and the e-tubes are the last resort. If it's rich at cruise then GOOD, go up to the next size bigger vents!

The dellorto emulsion tube is a strange and mystic thing.
I have lots with extra holes and solder and most of them are just junk, I save them to remember not to do that again.

GARRICK.CLARK · Posted: Mon Jun 08, 2015 11:52 pm Post subject:

It shows lean back fires after a few seconds under boost. It goes progressively leaner under boost . The back fire point is in the 15,s. So boost enrichment isn't working. My low speed driving is now fine.

Took the carb tops off last night. I slowly increased the size of the aluminum banjo bolt feed holes. There a lot less restricted now. I also ran a slightly bigger drill bit through the hole that feeds fuel to the inlet needle. I'm using a 225 needle and seat. I enlarged the cross holes a bit too. These mods should help feed the float bowl due to less restrictions. Wether it help the enrichment problem we'll see tonight. I may just buy a huge inlet needle and be done with it.
My fuel pressure is 5 psi ahead of boost pressure. I gaffer taped my mobile phone to the fan housing and recorded what the gauge was showing at a half bar boost. I need to check the fuel pump spec. I'm sure its an overkill one in terms of gallons per hour.

modok · Posted: Tue Jun 09, 2015 12:30 am Post subject:

FIVE PSI? whoa. May want to dial that down.

To improve flow you can make a hole bigger, or run more pressure. Making the hole bigger is twice as effective as more PSI. You don't need both. Both can be trouble. Set fuel pressure to only 3-4 psi, probably more towards 3.
CB's dellorto manual, which I assume you have since you bought the wonky emulsion tubes, does have a section on required fuel for HP, and as far as I know it is accurate. More flow that you need can overfill the bowls. Check it out.

And the same is true of the jets. you CANNOT PULL more fuel through a small main at high flows, but you can use use the emulsion tube to lean out a big main. The CB tube already has giant holes right at the top, and if that didn't do it then nothing will. And those holes are way too big IMO, and I wish I could steer you better far as tubes but it is tricky and I won't venture to guess. But essentially you have choice of four tubes developed for emission controlled alfas, and one tube from some guy at CB, seems definite that more and better choices could exist.

I actually want to guess.........but I won't. emulsion tubes are the last step.

GARRICK.CLARK · Posted: Tue Jun 09, 2015 5:15 am Post subject:

Good one Modok. I do have the Dell book. I'll read up on the amount of fuel- hp chart. My idle psi is 3 psi. It's 5 psi higher than the boost . So at 7 psi boost ,fuel psi is at 12.

GARRICK.CLARK · Posted: Tue Jun 09, 2015 12:34 pm Post subject:

Ok. Put it back together tonight. Its now done a full throttle run. Yay.
So drilled bigger the cross drills on the inlet needle. Drilled the aluminum banjo bolt centre hole larger. The end of the banjo bolt I counter sunk to the edge of the threads so fuel flows to the fuel channel in the carb top easier.also drilled the 4 holes in the banjo bolt bigger too. I don't think that 225 inlet needle and seats are big enough to flow well. I'll ring Euro carb tomorrow and see if they have had problems with larger size ones . They have them up to size 400.

Also noticed the mains come on very close to a closed throttle. This is with a 180 air. So out with them and back in with the 160,s.

I have put a 160 main jet in. If its rich at WOT can it be leaned with a few pounds extra boost.

Thanks.


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