Update on my custom turbo setup... also what's the best DME setup for it?

[Colby]

Well, Project Turbo Carrera is well on its way. I have the exhaust piping to the turbo done and once it warms up will have the IC plumbing sorted out. Next step (and the most time consuming) is all the little details. I still need to work out oil feed to and from turbo. To the turbo, Protomotive said tap into the oil pressure switch location. From the turbo they recommended aiming aluminum piping to the bottom of the timing chain cover.

But I don't know what to do regarding DME mods. I see three choices:

1) Protomotive: For $600 they will reprogram and chip my stock DME to "close" to what it should be (since I am not using their actual setup, they can only guess). They said I could then bring the car to them and for $400 more they would fine tune it. The catch; they say I have to use their fuel pressure regulator w/ their chip. Not a big deal....except they want $600 for it! For a fuel pressure regulator! Ridiculous. They say their's is "different" from all other fpr's (which sell for $130-200) but won't say how. This gameplaying turns me off to them.

2) Autothority: For the price of a chip, 2nd reprogram, and fpr from Protomotive, I can buy a MAS from Autothority and have them make me a custom chip. Any reason why I shouldn't go this route?

3) Huntley Racing: I REALLY like this setup. Like the old HKS VPC I ran on my Talon back in the day, this allows you total adjustment of your fuel curve on they fly. The downsides: 1) it uses an Air/Fuel ratio meter to be set by... not the best meter to tune a car to (too many other variables); 2) I assume this only adjusts fuel curve. Doesn't Protomotive also adjust ignition timing? This is a major factor in turbo'ed cars...

Whatcha all think? Come on Juan, Mike the Mechanic....give me your input.

Oh, on another note. Juan, like you I abandoned the twin turbo setup. Besides the double cost on many parts, I found there was a serious lack of space to run all the plumbing. Also, if I went twin turbo, there was NO chance of squeezing in a cat for emissions every other year. So I traded my two T3's off a Saab for a freshly rebuilt LARGE T3 off a Buick GN. AE .42/.82. It should work nicely. I am also running an IC off a Volvo of all things. Huge (17x18x2.5, and thats just the core) but I expect it will be less efficient and have more pressure drop than aftermarket units. But it will work for now (besides, w/ a stock block I am only going to run .5 bar or so).

Colby

[rfng]

Sounds nice, but your single T-3 turbocharger is too small. With a relatively small intercooler, you will need the turbo to output about 25-28 pounds of air per hour. And with the size of the intercooler your talking about I would guess closer to 30-32 pounds per hour @ 7 psi.

The largest T-3 compressor is only capable of about 17-22 pounds of air per hour. Although it should start making boost at about 2100-2200 rpm using a .48 rear housing and 2600 with a .82, you are going to run out of steam at about 4500- 5000 rpms, while the big horsepower I assume you are looking for wont happen until after 5000-5500.

I assume the numbers you posted are for the a/r of the rear turbine, which is in stock trim 72? The other problem that you might have is that with such a small turbo, you will overspin it and eventually burn out the bearing.

As for the fuel injection, try EFI systems, I believe they are in atlanta? The guy helped design the holley system and his system works pretty well on any digital injection system. It should have outputs for timing, fuel, and boost controll duty cycle
in 500 rpm increments.

I hope this helped a little. Good luck sounds like a good project.

[Colby]

Your analysis of the turbo I plan to use is a lot more scientific than my analogy (I say "plan" since I have a friend in the biz and is willing to keep trading me turbos until I find one I like...I must admit I did have my eye on a T4 w/ a .70/1.0 A/R). My logic was this turbo makes 14psi on a 3.8L in a Buick GN and can make that boost til 5K+. So I figured it would do fine at 7-10psi in my 3.2L. Maybe I was wrong.

But I don't want a HUGE turbo at this stage. It is a stock motor so, I can't run big boost. So why have a huge turbo if I can't make full use of it? Also, I can upgrade the compressor side anytime and have a full blown T4; a good time to do it would be when I rebuild the motor. But if you think it will run out of steam making even 7psi, then perhaps I should go for that T4. I just don't want a mega turbo I can't use, along w/ the mega turbo lag.

Colby

[Colby]

I should also add I concluded to use this turbo following the turbo match calculator on Ray Hall's website at:

http://www.turbofast.com.au/TFmatch.html

It actually doesn't suggest I move up to a T4 until I want 12psi, which is a long ways down the road (post rebuild and lower compression pistons). At 8 psi, it recommends a T3, 60 trim compressor, 1.06 turbine (so my is a little small, but should spool up even quicker). It should flow, according to this calculator, 28lbs/min and make roughly 312 hp. Of course this is just a rough estimate, but Ray Hall knows what he's doing.

Colby

[rfng]

I not saying that it won't work, as any turbo any size will make the boost. The problem with that as you over extend the turbo its efficiency goes down. And instead of producing manifold pressure, it will be producing heat.

The other problem with using such a small turbo, is the at speed acceleration/boost will be slow to build and it won't have that punch everyone expects from a turbo.

From a dead stop it will be alot of fun until about 4500-5000 rpms, where you won't build the horsepower but you will get all the torque.

If you are using a stock trim T-3 the rear outlet of it only measures 1.9 inches in diameter, will act like a stopper in the upper rpm range. The biggest problem I see with it is the amount of cubic inches you are trying to boost. Your compressor is a stock 42 or about 2.0 inducer.

A 3.2 is about 187 cubic inches? You intercooler is probably the equivalent of a 5.0 litre engine, so at 7000 rpms your trying to boost about 8 litres of air space.

I used a t-3 similar to yours on a 3 litre engine. It was fine up to about 4500 rpm, it made plenty of torque about 256 ft lbs at 4100 rpm @ 3 psi, but the horsepower gain was up to around 220-226? Non intercooled. So your looking at about 8 horsepower per psi of boost.

However, that what happens on all turbocharged cars. You generally have to make a choice, do I want it down low, medium, or high. With the big horsepower being developed up high.

I not trying to discourage you in anyway, just trying to save you some time.

Keep us posted.

[juan ruiz]

Colby I was looking foward to the twin turbo set up,Regarding your questions i be home and at the camp on Thursday and i can take a look at the fuel pressure regulator that they install in my ride ,Stay away from the mass flow from Autorithy all parts are modify from ford i have seen 3 set ups with nothing but troubble it seems that the calibration is never correct,to me the fuel /air is the must important part i rode in my car before the final tunning and is a huge difference,Mike did his set up in his own so he may have some tips,If im not mistaken my set up was the first one to be born but it was installed,Regarding Protomotive and the rest of them i have to tell you that this guys have years of research and they will help until certain extend problem is people pick their brains then they copy cat their staff and sell it,when i was doing my research this was and STILL is the worst part, help is VERY LIMITED when it comes to hot rod porsches.
If you turbo your 3.2 it be 4 of us myself,Mike,Merv and you .
Im one step ahead of the pack because im going to 3.3 so when the time comes for you guys to move up it be very easy i will have all the inf.so hang in there.
Regards Juan
3.2 Undercover

[orbmedia]

What about using a computer like Haltech that you can tune yourself completely with a laptop? This seems like the only way to go. You'll just need to figure out how to get the Carrera's MAS to adapt to it which shouldn't be too tough.

[Colby]

rfng: My friend has a .70 A/R T4 compressor housing and wheel (for only $50!) that will bolt right on to the turbo I have now. I am going to pick it up today. So I am going ahead as planned with this turbo. Then, should I feel I'm ready for more I will have a larger compressor ready and waiting. The .82 turbine housing seems just right size wise, and has a built in WG (which if I go to the .70 I know I will quickly outgrow; another reason I'm starting small and leaving open the possibility to expand later).

Maybe I will try the system Huntley sells (if I can address the timing issue ok; I can just add a MSD box...). Both them and Huntley also sell a MAP (mainifold air pressure) conversion. That is also a possibility, and seems like a good way to go for a turbo car.

I'll keep you all posted. Once I get the IC in this week (assuming it stops snowing and the garage warms up) I'll take some preliminary pics...

Colby

[RarlyL8]

Rich - you mean to say that when all things are the same, adding a larger intercooler will lower the effectiveness of the current turbo? So you need to upgrade the turbo and the intercooler to match one another? I was under the impression that you had to minimize pressure drop in the intercooler itself. Please elaborate.

Colby - very fortunate to have a buddy in the business. I'd like to talk with you and him when it gets closer to the time for me to purchase the turbos. I will be going with two small units. Plan to use a modified 930 scavanging system for oil return.
Can't wait to see those pix!

Juan - if I ever get down to Florida you've got to take me for a ride.

[beepbeep]

A buddy of mine is dual-turboing his early 3.0 930 ...

These are our conclusions (i'm also looking into it):

- Two T3's off a SAAB 9000T are too big...will start blowing around 4000RPM and make heaps of boost around 6000RPM....big time power, bad driveability.

- One T3 off a SAAB 9000T is too small for low-comp 930, ...makes a perfect match on turbo 2-2.3L engine , altough not being most efficient snail in the bussines.

For a warmed-up 3.2 or 3.0 Carrera running on low boost there is one mach made in heaven: Mitsubishi TD4-series...try to find one that sat on newer SAAB 9000 Aero....they are good for over 300HP, they spin up quickly, they are efficient....and unfortunately, they are watercooled :-) ... (but you should be able to run with water-mantle plugged)

T3 on 3.0L-engine blowing 0.5 bar will give you wonderful torque-curve from 2000 rpm upwards but don't expect any high-RPM rush. Car will run out of puff above 5500 RPM...which isn't always a bad thing.

Frankly, i believe such car would be a really good Auto-X contender due to flat and meaty torque-curve...unfortunately people want their Porsches peaky.

good luck anyway.


And by the way.... SDS is wonderful, cheap and MAP-equiped EFI that will solve your problems.

Check out http://www.sdsefi.com

[rfng]

Originally posted by RarlyL8
Rich - you mean to say that when all things are the same, adding a larger intercooler will lower the effectiveness of the current turbo? So you need to upgrade the turbo and the intercooler to match one another? I was under the impression that you had to minimize pressure drop in the intercooler itself. Please elaborate.

Sort of, when you increase the overall size of the intercooler, you are now asking the same compressor to initially charge a larger displacement of air space. Which in turn will create more lag. It depends alot on how much boost you are trying to run, under what conditions and what is the car being used for. You dont necessarily have to change turbos, but that is dependent on the specs of the compressor housing the a/r in the rear housing and the trim of the turbine and how much lag you are willing to suffer from. Alot of guys decrease the rear a/r housing to increase the inlet pressure to compensate for the added increase in initial displacement.

I think a lot of people confuse the a/r and the trim of the turbine. The a/r or aspect ratio, controls the inlet pressure to the turbine, which determines how fast the turbo will spool up. A big turbo spins at around a maximum of 100-130K rpm, while a smaller one up to around 170K. If you overspin the turbo the wheels will start to collapse and eventually break apart. This is why you will always see a large turbo with a smaller a/r and a small turbo with a larger one on a larger displacement motor. They are compensating for the displacement of the engine to prevent an overspin on a smaller turbo and to increase the inlet pressure on a larger turbo to get to boost sooner.

As for the trim, it acts more like a header system allowing the turbine evacuate the exhaust. The larger the trim of the turbine, the more exhaust it can move in the upper rpm range. But as with everything when yo gain somewhere you lose somewhere else. Bottom end response will decrease while top end performance will increase.

In addition, in a larger trim turbine, the backpressure in the system is decreased allowing the turbo to spin more freely and will increase the effectiveness of the engine as a pump in the upper rpm range. This is why you will see a lot of hardcore racers clip part of the fins on the turbine. Its cheaper than buying a new turbo when they increase the boost.

The same is true for the compressor side. You should first estimate how mcuh boost you are trying to run. What is the air temperature of the charge, and what is the drop in charge temperature the intercooler. Although I have seen literature stating 150 degrees is ok for the charge temperature , the optimal temperature is 105 degrees and below. So when you select that intercooler, you have to see how much is it going to help. I've always preferred a smaller core than the larger ones. Most of my driving is in the middle of the night, when the air temperature is cool, I don't run mega boost anymore, as I'm a little older, hopefully wiser, and like to keep my cars relatively reliable. Just a little more to keep me smiling. Besides I'm impatience, I can't wait all day for the boost.

Example-If one intercooler is 80% efficient and your normal operating air temperature is 75 degress, then you intercooler is able to drop the outlet temperature of the charge by that percentage. So if you go out and buy the largest intercooler you can find and its efficiency is rated at 95%, then you would drop the charge by an addition 15%. Not a big deal if your already under 105 degrees. but it can be if you run enough boost.

This would apply to a street car, as a race vehicle is presumably constantly under load and the compressor is up to speed, so lag is not as much of an issue. But I have seen race cars owners talked into these gigantic intercoolers, which is just too large for amount of boost they are running, and they often complain of the lag.

As for the pressure drop, all intercoolers will suffer a pressure drop as you are restricting the air flow, which causes the turbo to increase the amount of psi it flows to achieve the same amount of boost. However, you need that resistance to allow the intercooler time to transfer the heat away from the charge temperature as it is not instaneous as the plates and fins take time to absorb the heat and transfer it away. The problem is that everyone and their mother push the largest intercooler they can sell you. I know there are currently two types of intercooler design fins on the market. The square plates and the round plates. The round one create less of a pressure drop than the square one as it flows slighty better, but the efficiency of those units are not a good as the square ones. I've used both and the square one do a better job.


Hope this helped.

[WydRyd]

Excellent info there Rfng!

Just FYI, I'm not using the same turbo as Mike/Juan/Colby. I've opted to stick with what Porsche use on their factory Turbo's (91-94). I'm using a KKK K27-7200 (the quick spooling unit everyone raves on about for 930 upgrades).

I figure, if these are quick spooling on a 930 at 7.0:1 Compression, it should be super quick with a 9.5:1 3.2 Carrera WITH Apexi AVC-R EBC

Again, I only plan to run 0.7bar initially (on 98 Octane Fuel).

My system is based on the Protomotive Motronic CHIP & Protomotive "Custom" Fuel Press Reg'r. They are expensive, BUT these are developed together and used in conjunction for optimum fuel delivery and ignition timing based on their 0.7bar/9.5:1 kit (or 0.85bar at 8.8:1 C/R).

My intercooler is based on a tube&fin core. I researched both tube&fin and bar&plate and the best one for horizontally mounted application is tube&fin. Bar&Plate is great for front mounted applications where there is greater airflow directly onto the core. Tube&Fin is suppose to be better for street driving, whereas bar&plate is better for track use. Bar&Plate is also much more expensive & also much heavier than tube&fin.

ALL of Porsche's/RUF's/TechArt's turbo 911's use tube&fin cores, so I figure, WHY try to re-invent the wheel and use bar&plate in a horizontal application when clearly, tube&fin is THE core of choice for manufacturers.

The intercooler Mike/Juan and myself are/will be running are over 940Cubic Inches in size and exhibit 0.7psi drop across the core at 12psi boost. Efficiency is approximately 75-80%.

I will confirm these figures when I get my car back. I have a digital temp gauge (dual read-outs) which will display inlet and outlet temps on the intercooler, so that'll be interesting to see exactly what sort of efficiency they are running at. The beauty about the inlet end tank design is that they distribute 90% of the intake charge across the face of the core, improving charge air distribution and cooling efficiency.

FWIW, Mike isn't running a Protomotive Fuel Press Reg'r, but he is running Protomotive Software in his DME and it works great.

I'll stop rambling on now...

[WydRyd]

Forgot to mention, we all got our Intercoolers made by the best fabricator in Australia (IMO). They are known as Aluminium Radiators & Engineering. They are a Brisbane based fabricator of aftermarket intercoolers, oil coolers, radiators and the quality is second to none.

Check out www.are.com.au

My secondary oil cooler is JUST as pretty as the intercooler.

Prices are VERY reasonable too! Just don't expect it in a couple weeks. These guys take pride in their work and the end result shows.

Ask for Richard if/when you e-mail them for info. Tell him Merv recommended you and he'd do you a good deal (: hopefully

NOTE: I have NO affiliation with A.R.E whatsoever, just a VERY happy customer TWICE

[930fan]

The Dastek Unichip would be the best option for you in my opinion.

Find out more here: http://www.theracersgroup.com/theprogram_unichip.html


and here: http://www.airpowersystems.com.au/unichip/unichip.htm

Might be a good idea to get an upgraded fpr too. I've read that the TPC low boost supercharger kit for the 3.6 needs a 7th injector and a fpr to avoid going lean but then they have much higher c/r than your 3.2.

The most important element in getting a safe and powerful state of tune is the installer dialing in your car. Ask questions and try to find out his rep.