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Discussion Starter · #1 ·
Is anyone using 034 for mapped boost control?

I'm at a crossroads with my project. I have a 3B motor, ecu, and wiring harness that has been cut. I can either repair the harness or buy a new one, and then I have to worry about getting a chip burned every time I make a mod, which I plan on making a lot of.

Anyway, in the meantime before I upgrade the rods and put a huge turbo on, I need to be able to limit the boost at certain rpms either to protect the turbo or the rods. I know there are general purpose outputs that can be used for boost control, but are people using it and how is it working out?
 

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Ken, you're correct, the GPO outputs can be used for boost control, currently there is no active, closed loop boost control build into 034efi, but the GPO's can be indirectly used for boost control by sending a PWM output to a frequency valve that will modify the wastegate signal. I have been testing this with pretty good results, I've found that if the max boost is set manually at say, 22psi, using a bleed valve, then the GPO can control a solenoid intercepting this signal. Then you can modify the boost control safely and much more accurately than w/o using a bleed valve.

Eventually, we'll build into IIb and c a closed loop boost control function for rock solid, totally dedicated boost control.

IMO, however, using a plain old "boost valve" is a great and reliable way to control boost. Your stock spring will give you about 6psi or so, so you're only going to get more boost if you want it, a good way is using a $60 TurboXS valve or similar, I've used one of these all the way to 300whp and 22+psi boost.

Also, as you're finding, using a Motrinic ECU can really start adding up once you include the cost of the ECU, harness, and all the Chip burning, some of my customers say they could have bought two or three 034efi IIc ECU's for the money they've sent some domestic tuners chips and still haven't had cars that ran well, and that was with the distributor 3B system.

Obviously, you knew I was going to take that angle =), but I think you see it to, so let me know if I can help, it would be great to get your project up and running.
 

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Discussion Starter · #3 ·
Hi Javad,

Yeah, I do like manual boost control too. The problem is if I initially run a K24, I can get more boost at low rpms but at higher rpms I have to limit the boost to preserve the turbo from overspinning. Then on the other end of the spectrum, when I put a bigger turbo on, let's say before I upgrade the rods, I have to run lower than max boost at lower rpms to keep torque manageable, but I'd be able to crank it up higher at higher rpms once the crank is spinning. I think these two things necessitate some kind of mapped boost control, if I want to optimize power in either situation. That's what I understand anyway.

I like the sophistication and safeguards of the stock Motronic, and if I could burn my own chips and such I'd would tinker with it myself. Actually I would like to learn how to do that, because I think it would be interesting and fun. The same tuning fun applies to 034. But then with the Motronic I still have the distributor. Actually tho', since I have both the 200q20v and 3B donor motor for the 4kstq project, I'm likely to get at least one Motronic chip for use on the 200, which I think isn't going to be the gonzo race car that for example Justin is building.

Maybe with the existing "open loop" boost control of 034, I can set up some kind of two stage boost control, and just have the ECU handle switching between the stages.

I like the direct ignition aspect of 034, and of course the programmability and no need for a MAF sensor.

So, 034 can output a PWM signal that can run the OEM "N75"/WGF valve?

I have plenty to keep myself busy with just the hardware, like prepping and installing the motor itself. I'm gonna be in research mode for a while. Lately I've been reading the S2Forums, which has a lot of enthusiastic 20vt owners doing interesting stuff.

Where should questions about 034 turbos be directed? I don't have many specific questions, but I am curious which one would be best for something to be driven on the street with a 3B, RS2 EM, and upgraded rods/bearings. I would like to have some low end torque, but be able to generate plenty of usable efficient boost at 7k rpm. I think I would want something similar to an RS2 turbo, perhaps taking advantage of new technology.

I'm still inclined to prefer a ball bearing unit, which you have in the past said wasn't worth the expense, but lately have made comments about a perhaps new version on the market expressing interest. What's the state of the industry regarding ball bearing turbos that would apply to VAG/KKK cars?

Also, I have heard people having reliability problems with KKK/Garrett hybrid turbos in general, even with new ones. I know they are available from different suppliers, including 034. I understand 034's are rebuilt in some way, right? What kind of durability have they demonstrated? Any issues?

Oh yeah, another newbie question. Is a Garrett T4 the same as a T04?

Thanks Javad,

Ken

JShadzi said:
Ken, you're correct, the GPO outputs can be used for boost control, currently there is no active, closed loop boost control build into 034efi, but the GPO's can be indirectly used for boost control by sending a PWM output to a frequency valve that will modify the wastegate signal. I have been testing this with pretty good results, I've found that if the max boost is set manually at say, 22psi, using a bleed valve, then the GPO can control a solenoid intercepting this signal. Then you can modify the boost control safely and much more accurately than w/o using a bleed valve.

Eventually, we'll build into IIb and c a closed loop boost control function for rock solid, totally dedicated boost control.

IMO, however, using a plain old "boost valve" is a great and reliable way to control boost. Your stock spring will give you about 6psi or so, so you're only going to get more boost if you want it, a good way is using a $60 TurboXS valve or similar, I've used one of these all the way to 300whp and 22+psi boost.

Also, as you're finding, using a Motrinic ECU can really start adding up once you include the cost of the ECU, harness, and all the Chip burning, some of my customers say they could have bought two or three 034efi IIc ECU's for the money they've sent some domestic tuners chips and still haven't had cars that ran well, and that was with the distributor 3B system.

Obviously, you knew I was going to take that angle =), but I think you see it to, so let me know if I can help, it would be great to get your project up and running.
 

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Hey Ken,

I think that maybe you're putting a little too much importance on closed loop boost control, there is a lot to be said for the performance of linear boost control, and while the ability to control boost levels at different RPM ranges is nice, its definitely not a necessity. Not that you're saying that its manditory, but there is not reason your K24 won't run just fine up to 20+ psi linear thru the power band.

Yes, the PWM outputs will control an N75 valve with modest resolution, but using the set bleed greatly increases the useability (as I described in the earlier post).

We can talk turbos here, maybe start a new topic if you like.

From what you describe, I'd definitely recommend the 034 K26/T4 hybrid, this turbo gives max boost by 3krpm, and power begins climing hard by 3500rpm, and will deliver all the way to 7krpm. This turbo is know good to over 350whp. Anything smaller will poop out by the high rpm range.

With regard to BB turbos, yes, for the $5-600 premium, its not quite worth it, but prices are coming down and we are testing a new GT28/T04E that may be a very good compromise. Many of the BB solutions on the market have not proven themselves reliable, the Garret GT BB turbos are very reliable, so this would be a great solution for about $1100. I may be testing one soon so we'll see. Thus far I've sold some turbos with the Turbonetics BB center section, reliability has been good. Yes, all the turbos from 034efi are rebuilt, they have been very reliable if treated and installed properly.

Yes, Garret T3 or T4 equals T03 and T04, different compressor housing options go by E, O, B etc.
 
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