Hi everyone,

Trying to learn to map the car myself (keeping it safe and sensible and taking baby steps) but there are a couple of things that have me scratching my head. Can anyone advise on these perhaps? Would really appreciate the help. Ran quite nicely on the TD04 with higher boost but the VF34 with larger injectors are not so straightforward.

1. The boost solenoid duty cycle would not go over 90.6%. Currently I have the OEM Subaru 3-port one (no pills installed) but I tried the 2-port today and it was exactly the same - pegged at 90.6 despite the map requesting 100. I tried raising the boost target way up just to see if that affects it but it was the same. I'm sure it's an easy fix but I'm just not seeing it.

2. The intake temperature reads -28 at all times. Running the original MAF and all but I am not sure if the MAF is supposed to measure both the flow and the temperature or if this parameter is in there for running MAFless and is not used in my setup.

Thanks for the help!

Alex

 

Alex, on point 1, 100% duty bleeds all boost pressure away from the turbo actuator meaning it will produce as much boost pressure the turbo is capable of. Great for spool areas of the map but you need a lower value to control boost. Why do you want it to be 100%?

 

I'm looking into point 2 myself as my type r has the oe air temp sensor but I think the logging must be looking for another input. I'm also thinking that this is of more user when running mafless.

 

I want it to be at 100% before it spools up to, well, make it spool up quicker

At the moment the car is no fun to drive with the boost reaching maximum at 4500 rpm Then it's a bit of a train but the useable rev range is quite limited

 

4500RPM until full boost seems very high, is the VF34 a big turbo? When you changed from the TD04, did you also change the restrictor pill?

Can you grab a few screen shots of the boost duty and target maps?

I'm on full boost by 2500/3000RPM with the TD04 and to be honest I don't think I've ever seen my BCS duty go to 100% either, will check today!

As for the intake air temp, I had to buy a separate sensor for when I go MAFless. It uses the signal wire for the MAF sensor as the input to the ECU. My car doesn't have an OE IAT sensor, UK turbo with 8S ECU. Mine reads -28 constantly too.

 

Just noticed you've no pills installed. Maybe you should.

 

As a side note, I cant imagine 100% duty on any type of solenoid being a good thing.

My vf23 hits 1.35 at 4k, or maybe earlier, but defo full boost at 4k and that's with a p20 exhaust housing.

 

Thanks for chipping in, guys

Andy suggested in one of the threads in this section going 100% on the BCS early in the rev range to help with the spool-up, and that makes sense.

Regarding the pills - you don't need to run them because a 3-port BCS is capable of shutting the pressure to the wastegate actuator completely. Subaru uses a pill in the line from the BCS to the intake return on the 3-port but there should be no need for that one either, really. When I tried the 2-port it had the pill where it needs to be.

The VF34 is really not a big turbo, slightly larger than a VF35 but with ball bearings so should spool nice an early. I'm attaching a couple of screenshots of a 2-gear run from yesterday.

 

Your boost does come on very slow! Mine spools really quickly, overshoots a little until the boost duty map takes control and then a nice flat line almost to redline. What kind of up pipe are you using?

 

Running a stock exhaust manifold and uppipe and a bellmouth decat downpipe.

 

I've noticed in your table that the throttle position never goes higher than 84.4%. At 84% the engine load is 44 and when you do get to 84.4% the load goes to 54 or so. I think that could be your problem, partly at least.

 

Also, at high engine loads my BCS duty map is way down to 50/60% maximum to keep the boost levels down.

 

What BCS are you running?

As for the throttle position - could be! However, the range I have is ca 8.5 to 85 % and it's always been like that, I've never touched the TPS or the throttle body itself, really.

 

I had been running the standard 2 port but recently changed to a Subaru 3 port. Didn't make much difference, I only had to tweak the duty map a little. My TPS range is about 6% to 97%, might be something for you to check out.

 

Wot on mine is 86.6 and idle is 8.3 and that's a 97 type r.

A 2nd gear run will see boost come in slower due to load. I usually log a 4th gear pull where speed limits permit.

 

Yeah, usually 3rd and 4th gear for me. Things happen too fast in 2nd. 86% is probably ok because the engine load is higher than the maximum value in the map axis. Maybe the op should adjust the map axis to include his maximum BCS duty and boost target at a lower engine load. That 0.4% on his logs makes quite a difference to the calculated engine load.

 

Looking at your logs the duty on the bcs is nearly 90% at full boost. Mine would be around 55% or lower for the same boost on a 2 port. I'm no expert but that looks wrong to me. Also, log cyclic knock count too.

Even with my duty set to 100% I get the logs showing 90.6. That may well be a safety feature so as not to burn out the bcs.

 

OK, that's interesting to know that I'm not the only one whose BCS duty cycle does not go over 90.6%

Went out and did a couple of runs in third gear just to show you guys where I'm standing at the moment.

The full log is here (hopefully).

Turned the max BCS DC down a couple of clicks as it was overboosting slightly and attached is a screenshot of what I ended up with. I agree, the values are perhaps a bit higher than expected but I thought that was normal for a 3-port running no pill?

Oh, and my throttle position sensor range is 8.2 to 84.4

Cheers,
Alex

 

I ran my 3 port earlier with no pill to see what happened, not a lot it turns out. Didn't make any difference that I could see. However, your max BCS duty cycles are really high compared to mine and others. I don't think you should need them at that level. Is your wastegate working ok on the turbo itself?

 

Is your 3port plumbed in properly?

 

This is a used turbocharger but it was visually in very good condition with everything moving freely, including the WG.

I followed this guide for plumbing

 

I followed the same guide too, works ok for me.

 

Has your WG preload been set up properly?

 

It's as it arrived and the actuator arm is not adjustable on the VF34. When I tried it at zero BCS duty cycle (wastegate pressure) the boost was just over 0.5 bar

 

Did you use a restrictor in the BCS outlet line?

 

Ah right, I forgot the VF range weren't adjustable. I'm pretty sure WG pressure on my TD04 is 0.7bar.

And yes, I did use my original 1.2mm restrictor on the bottom pipe from the 3 port to the intake pipe.

 

Tomorrow I'll double-check the BCS plumbing, just in case, and also will go over the whole installation. Other than that I'm out of ideas

 

Here's a shot from a dodgy 3rd gear pull earlier, another car pulled out in front of me and I couldn't get on the gas fully but you can see how my boost profile differs.

 

 

That looks much better than mine

Haven't had a chance to try anything today just yet, but in the meantime I was wondering if running a stock (plastic) bypass valve could have something to do with this issue I'm having?