Polishing a diamond in the rough - saga of sorting the 930/4
 

Hi, guys, remember me? That happy guy that made the x-country journey so many month ago? Well, i'm still happy, but the last several month have been like watching the 'Sound of Music' too many times... i've smiled, i've cried, i've cursed 'Ze Germans' and, cried some more as my wallet lightened, then ultimately laughed some more to the music of the zork and spooling Garret... Thanks too all the excellent input and insight from all of you initially, along with searching past post, my tuner and i have finally sorted the beast. Like the x-country trip, through this process, i have learned even more about the car, and how to safely get the most from her.

First off, the TEC1 system proved simply too archaic to work with in any fashion, and was ditched. To tune these engines, knowledge is power, and the TEC1 from a tuning standpoint just had a GED. Looking at all the mgmt systems, and other opinions on Electromotive, we decided to go with the new TEC-GT system. The system is phenomenal. The Install was painless, the start-up maps we built with Fred and Uva's help from Electromotive were great, and the tuning has been staightforward. I know this board has knocked Electro, but so far my experience has been nothing but postive.

Second, the fuel system was a major rate limiting step. This motor used a stock Carrera manifold and FPR to try and feed a built turbo motor. The no-boost fuel pressure was brought up to 41 from 35, but the stock FPR and lines just didn't cut it under boost after 4000, when went lean, so an Aeoromotive FPR and braided lines allowed us get up to 52 psi with boost. Running stock fuel rail and injectors.

With the TEC-gt installed, and tuning to get AFR in the solid 11-12 range, our first run on the dyno resulted in ... oil dripping underneath the car. My tuner freaked, i freaked, but i looked and saw it was coming from the area around the engine cooler. Replaced the seals/ thermostat o-ring and were back in leak-free bizness. With conservative initial tuning, are seeing good numbers.

As of this weekend, the last issue to address is boost control. Have a Tial 46mm which is allowing WAAAAY to much boost (up to 1.3 Bar:eek:) but making relatively safely with good AFRs. Want to limit to 1.0/1.1 max depending on track or street, However, as i have no idea what spring(s) are in the wastegate, or if it is malfunctioning, will pull and check this week.

Per past thread search, do you guys think the best route is to install a .8 bar spring, then adjust with a MBC? What advantage does a EBC have over a MBC? What brand of BC are you guys using?SmileWavy

at least tial springs are cheap right?

good to hear things are going well

LOL! Yeah, Jer, the tuning and dyno time is the real wallet buster. Has been completely worth it, as the car starts and idle better when cold, and accelerates throughout the powerband more crisply with less lag. This car amazes me every time i jump in it!!

The most important advice you guys gave me was to find someone with a good understanding of these systems... My tuner was the most important guy in the whole process.

When I went from a stock w/g to a Tial I installed a mechanical boost gauge to make sure I didn't make an expensive mistake.

This is good to hear!

Yes please, find a 0.8 bar spring and install it. You can always raise boost above it, but once you have harder spring you can never lower it under it's basic boost.

I don't know much about TEC-gt but it's worth checking if it has functionality to control boost. If it has, all you need is softer spring and solenoid to control the boost from ECU. Then you can map the boost according to your needs.

I personally don't like using adjustable FPR's as they are "fuzzy" things that make mapping hard. Especially rising ratio FPR's. Once they are re-adjusted from position where you mapped your ECU, you need to do it all over again.

I recommend using plain 3-bar boost regulator and doing a map with it. If it fails, it's easy to replace it and there is no adjustment involved. If fueling isn't enough on 3 bar fuel pressure, find yourself a bigger injectors. Injectors should be sized so you reach roughly 80% duty cycle on max output.

Goran, thank you for your most excellent input as always. Your advice is most timely, as we are going to go through our boost control options on the TEC-GT system, which from our understanding with Electro, are quite capable. My tuning guy is more of a fan of manual BC's, but he asked me to ask for input from this board.

First step is to install the .8 spring tho.

You could do so much more with the tecGT than with a MBC.

Maybe put a .6 bar spring in the TIAL

Pick a solenoid to control with the tecGT

Careful mapping of the dutycycle on that valve in the wastegate line would let you do all sorts of things.

Not only could you control the boost pressure, but the boost curve as well.

Experimenting with higher dutycycle on the valve just as the turbo is starting to spool would let the turbo spool harder. There are countless scenarios you could play with.

Isn't one of the inputs config. as a speed input? Could this give you m.p.h. based boost control?

Then theres getting caught in, or playing in the rain, where a little more drivability would be nice,

You could eventually work out maybe 3-4 different boost "maps"
and have a simple multi position switch on the dash.

Simply wire the ground from your boost control valve to each different output wire from the GT, through the switch, based on which map you wanted to run.

It would take some time to get sorted but may be worth it,

Most modern cars control their turbos this way, seems like almost a waste not to utilize those features in the new control unit.

Good luck, can't wait to hear more about the beast.

Good to hear she's back up and runnin' around! Can't wait to see her :)

I had to run a very soft Tial spring in my wastegate and then adjust the boost up using an electronic boost controller. It turned out to be the only way to get the boost response and limits that I wanted.

I second using softer spring. I have a 0.5 bar spring in my Tial. With the boost controller you can turn the boost up to 1.5 bar if you want :D But as Goran said, you can't lower it below the spring threshold. With some headers, a 0.5 bar spring may already give you a minimum of 0.6/0.7 bar boost.

Well, made some progress today. First off, cracked the Tial and found a large red (.7bar) and small red (.3bar) spring. The 'wastegate guru' in the shop said that with that combo of springs, the additive boost was going to be all over the place. Per the advice of you guys, we decided to go with the .7 bar spring only, and found the WG to be boost consistently to .7 bar.

Tuning for a while at .7 bar, we achieved 370hp and 340lb/ft at 5800, with rock solid AFRs between 11 and 12.

At the end of the day, we discussed going with an EBC tied in to the TEC system, along the lines of what you recommended Mike. This would definately be very neat, but call me a romantic, but i am a sucker for the old school way of doing stuff. In a nod to the 934's of old, i decided to go with installing a MBC between the seats.
http://forums.pelicanparts.com/uploa...1219708013.jpg
The only decent one that i could find was one like these, but in silver.
http://forums.pelicanparts.com/uploa...1219708147.jpg
Does anyone know where i can find a MBC that looks similar to the factory's?

Anyhoo... Just something sexy about it. Will tune at .9 and 1.1 bars on both street and race gas.

Not bad for the first real day of tuning... but just getting started. :)

The gadget between the seats are also known as 'Dial A Death' :)

Hey Juice! Good to see you are having positive progress. I built a carbon panel that fits over the bottom mount of my Hargett shifter and placed a MBC under the shifter. I feel the MBC are more consistant. I too tried to find a Porsche Motorsports MBC which is the one in the picture. They are no longer available, I asked Kevin at Gunnar if he could get me one and he was the one who let me know they are no longer available. He did try to see if there was any in the system sitting on a shelf but no luck. I did see one on ebay a while back go for a arm and a leg. Maybe your buddy with all those prototype cars may know someone who will part with one. For now I am using a Turbonetics MBC. Not pretty but it is well hid down between the seats. I did think of machining my own MBC to look like a Motorsports unit but haven't got that far. Keep up the progress "G"

Very aware of the history of said 'gadget', but through the marvel of modern tuning tech, we a programming the TEC-GT to prevent overboost, and the MBC will only be adjustable up to 1.1 bar.

G, thanks for the pix... always wondered what the fabled factory boost knob looked like up close. That's one serious looking piece! Couldnt seem to get a good look a one last year at Rennsport. Doesn't seem like it would be difficult to fabricat a reasonable facimile. BTW, thanks for all your help on understanding the limitation of the fuel pressure/ fuel system issues way back when we were trying to make the TEC-1 work.

Installing a WBO2 monitor and MBC this weekend then, will tune to further when i get back from Sicily in two weeks. Considering what the engine was making even when poorly tuned, i'm hoping to safely run .8-.9 bar and 400+. We'll see.

Hello!

If possible, I advice not to use dial-style boost and to let that part be handled by ECU. Reason for this is that you can connect ECU to control the boost in such way that it keeps wastegate totally shut until preset boost is achieved, then open it just enough to keep that bost.

Also, you can connect it in differential fashion (feeding boost signal trough solenoid to the top portion of the bell), thus further enhancing the spring force that keeps the valve seated. This will guarantee zero boost creep and best possible spoolup. Also, it will prevent "oh, let's see what this knob do...hmm, why does engine sounds funny?"-problems.

MBC is mechanical device and will start opening the wastegate in advance, in "analog" fashion. This might or might be not be felt, YMMV.

Regards,

I'm using a motorsports "wheel of death", i'll check with my shop to see if they have another one sitting around for ya :)

Hmmm, seems i am getting a lot of feedback along this line. Goran, havent checked with my shop for input, but will any boost actuating solenoid work for this application, such as the one here http://www.034motorsport.com/product_info.php?products_id=480 ?
If this is indeed the safest way to go, then as much as i like the MBC concept, will steer to the EBC.

Gabriel, you're the man if you can locate a factory knob! FYI - I've started to talk up your possible road trip to NC in the 'Blackbird' to see the GTR , so make sure your guys are on schedule to finish up by the time you get back from Iraq;) BTW, my friend Matt Drendle just added the 'Bad Boyz' 3.6 turbo and Mobil 1 GT1 to his collection, and said it should be fine if we wanted to stop by his place on the way to the 'Tail of the Dragon' Gonna be a helluva trip if you can make it.

My "wheel o' death". I keep it in the engine compartment away from my greedy hands - Joe P MBC. Maybe all MBCs are like this, but one thing I like is turning the knob clockwise REDUCES your boost (obviously no less than what spring is in the wastegate), and counter-clockwise INCREASES your boost; the opposite of what you'd think. In addition, I like the tiny size. I have a proper billet mounting bracket for it, I just haven't installed that yet.
http://forums.pelicanparts.com/uploa...1219845782.jpg

Juicersr- which shifter is that in the picture?