OT Need help lighting my turbo up

[hjtrbo]

Very OT. This is my own Ford inline 6cyl 4L dual VVT with a GTX3584RS. Barra engine for those familiar with them. 2010 Ford XR6T. Stock cams. Usual bolt ons.

I'm struggling to get the turbo to light up from 2000 - 2600rpm. I'm getting full boost at 3200rpm. I'm not familiar with turbo theory. I've tried moving the cams around, I.e. max advance and 0 overlap and other combinations with no success. The thing just near flatlines slowly building boost. I'm still tuning this thing so excuse the boost spike.

Just wondering anyone would be willing to take a look and provide some pointers.

[blindsquirrel]

Low spark timing... put the fire in the pipe (and turbine) instead of focusing on keeping all the heat in the cylinder. 20* is way too high to get it to light off, pull it down to single digits or even near zero and see what happens.

[hjtrbo]

Thanks, i'll give it a test.

[blindsquirrel]

That turbo has a 68x62mm turbine wheel, I wouldn't think that would be laggy at all on a 4.0L?

[hjtrbo]

Weird huh. That's what I thought too. I enlarged the internal wastegate port from 32 to 38mm, that job went well. But for some reason I decided to blend the casting from the flange into the entry of the wastegate port. I'm wondering if I've upset the gas path into the turbine. If the spark doesn't work, I've got an unmodified rear housing to try.

[blindsquirrel]

If the WG is sealing when closed the flow path really should not matter. 'Best practice' is to give all the priority to an external WG, with the path to the turbine off at sometimes a right angle. It'll get where it needs to go as long as it has no alternative.

[hjtrbo]

I wired the wastegate shut and see similar results. Sealing is pretty good. New day today, I've got a new timing map to try as per your response. Fingers crossed.

The PCM has a cam adder table for boost error but no corresponding spark table, no rolling antilag .

[blindsquirrel]

Since it's not a megahugelarge turbine like I was initially thinking, you might also try more timing if it will take it. More power = more exhaust flow.

[hjtrbo]

She's severely knock limited the poor thing, knock ears start getting noisy with a few more degrees in it on boost. 10:1 comp on pump gas, built motor. Just trying to get a good circa 400rwhp base tune going before switching on the meth port injection and also doing a separate e85 tune. I'm there with my number, just want to get it onto boost 500rpm earlier.

HP target once on the right fuel is 730rwhp, she's gonna be a handful on the street on the 245 Michelins. Daily driver

[hjtrbo]

Ah I see, I can try timing both ways. I'll park the cams at intake full advance and 0 overlap for now and overlay the logs. I'll come back with results. Street tuning is a PITA

[07GTS]

i would have thought opening the exhaust valve as soon as u can too should help get more if the initial ''bang'' in the exhaust and heat ?

[hjtrbo]

I'm still learning this shit, it's always confused me. I need to see it visually in some nice 3d animation for it to click. We want the exhaust valve opening earlier, yes I get that. Question; if not careful we can introduce to much overlap?

Here is the 2 cam tables. The exhaust cam is cal'd as overlap. Spool area is 1.2 - 1.6 load, 1750 - 3000rpm
I cant advance the intake anymore -10 is the limit


Overlap table. I've tried some changes here with not much success. Any suggestions?

[hjtrbo]

Oh and Greg, if you're watching, I'm still working on your project . Slow progress, but moving forward

[GHuggins]

Might want to stop focusing on the 1+ load and focus on the .4 to .8 range 1's already making positive pressure or should be a small amount. I don't guess injection would help a whole lot since you're moving the cam everywhere and it's not showing anything unless it's just really advanced. Normally for small turbo's I retard injection about 15 degress to keep fuel in the chamber, then advance the timing as much as it'll allow then continue that going into boost. Injection is what always changes turbo spoil on every turbo setup I've done. Most Ford cals follow the cam with injection timing. Not sure if yours is? I would make 100% sure that the wastegate isn't actually leaking. Believe you've done that though.

[GHuggins]

This is a 4 cyl. Yeah I know, but only thing I could think of comparable to show. If you open the file I started with vs what I did you'll be able to see where I changed cam timing and injection. It picked up just shy of 100 lbft and 60 hp on the dyno. Didn't improve much on the spoiling, but did build torque and power better starting around 2000 rpms then carried that gain exponentially to full boost peak. It was a big turbo on a small engine.

[SiriusC1024]

Throw some mass at it. Enrich PE or hit it with WMI.

Retard the timing so that less heat is converted into work on the piston.

Turbine housing and downpipe insulated?

[blindsquirrel]

I wouldn't think a reasonably sized turbine on an engine that large would need silly antilag tricks. Timing in boost isn't an issue with getting it to spool, but rather the timing (and power, and exhaust flow) out of boost. If it can take more spark timing in the N/A portion it'll make more torque and that means more exhaust volume.

Once the turbo/turbine gets large enough it gets into the strange realm where you have to start thinking about it as a turbocharger that just happens to be driven by a piston engine. This shouldn't be anywhere near that point yet.

[Alvin]

I've always had them do better with a decent amount advance and a reasonable AFR than trying to retard timing and add extra fuel. If what your messing with supports live tuning.. we've done this on a transbrake or footbraking while moving advance up and down.

Makes me wonder if that is another internet myth repeated like gospel by those who never tried it.

[hjtrbo]

I've got a few maps to try. No live tuning unfortunately.

Thanks for all your input guys. I'll be back with some pretty data logs all going well. You've all given me some good insight.

I have a feeling though this will all end with me pulling the turbo off and finding something has moved and it's changed my actuator preload or something to affect the wg flap seal. FYI she's internally gated with a Turbosmart IWG-75 twin port actuator on a 3 port MAC boost solenoid plumbed correctly. 4" dump -> 3.5" cat-less exhaust.

[SiriusC1024]

I don't see how thermodynamics qualifies as an internet myth. Turbines work on temperature and mass flow. Higher EGT's will spool quicker.

It'd be nice to see some sort of airflow channel in the log so the compressor map can be tracked.