Big CR and boost - Going full guns on a 911/930

[kenikh]

I posted this in another thread, but think it makes more sense to ask in a dedicated thread, to the crowd that would know...

There are some new(er) variables that I think need to be discussed in relation to building a turo motor these days.

Given the ability of a progressive, ECU controlled methanol injection system to functionally boost premium fuel's octane to ~108 at full blast, the ability to blow water mist into the post-IC airstream (temp sensor controlled) to further cool the intake charge, and J&S now having dialed in their per-cylinder knock retard for the 911/930, my guess is that the old "max" boost and CR numbers, even for a full-tilt, twin plug EFI don't apply.

Is it unreasonable to expect 1.2 bar from a 9.5:1 static CR, twin plug, big IC, full option EFI motor w/ knock control and all of the above bits? Maybe. This does result in an (at rest, boost corrected) dynamic CR of 16.3:1.

That said, those little watercooled Mitsubishi Evos, running the same spec engine management (EFI/knock control/big FMIC/H2O & meth injection) as above are regularly running near 30 pounds (2 BAR!!!) of boost at 9.5:1 static CR, and pumping a streetable, reliable, 500+++ HP from a 2 liter fourbanger.

Discounting the advantage of water cooling, 1.2 BAR seems downright accessible to an air-cooled motor if properly designed and managed. If that motor is a turbo with 80mm-85mm pistons (much smaller pistons than any production Porsche turbo), it seems even more likely.

This much boost might blow the heads off of a 911, ripping those Supertec head studs right out of their case savers, but the question begs to be answered.

Is this crazy talk or are we just taking convention for granted in light of refined technology? Is it just just ignored since 930s can already make all the power you'd want using proven methods due to the big displacement of factory turbo motors?

I'd love to get your thoughts...

[mark houghton]

[QUOTE=kenikh;4794220]

This much boost might blow the heads off of a 911, ripping those Supertec head studs right out of their case savers, but the question begs to be answered.

QUOTE]

That's probably the biggest risk. If you could hold the engine together, and added all the anti-knock and meth-injection gizzmos to deal with the higher CR, heat, and preignition, due to the cubic inches involved you could conceivably punch out some very serious horsepower. Way beyond the scope of my knowledge, but since I was lurking around the forum already....why not be the first to reply!

There are people on this forum that are cranking out well in excess of 500hp without increasing the CR (to my knowledge, at least). Let's hear from them.

[JBL930]

Get on the phone to Eddie Bello, i doubt there is anyone running higher boost than that man on an aircooled flat 6

[edbaus]

QUOTE]

There are people on this forum that are cranking out well in excess of 500hp without increasing the CR (to my knowledge, at least). Let's hear from them.[/QUOTE]

Take a cue from the 993 TT setup. I believe that the CR on those motors was 9.0:1.

The reason given for the increase was the better engine controls that the motor had. It still used the same diameter and length of head studs, so that did not seem to be an issue.

The biggest advantage of the higher compression ratio is low end torque and drivablility, not ultimate Hp. You can achieve very high Hp with very low CR. It is also easier to control. But, the downside is that the car is a brick at low RPM. The way around that is to put on a pair of smaller high effieciency turbos that spool up very fast.

Depends on your goal with the car. If you are looking for the ultimate track car, go for the low compression and the highest efficiency turbo that you can get for your airflow (it may be one or two depending on your redline). If you are looking for a great street car, then get the higher compression motor and smaller turbos.

Also, it all depends on how long you expect the motor to live and how dramatic you would like the end of life moment to be.

Ed

[930gt-40r]

I ran 27 psi through mine a few times. Only thing that ever failed on my motor was the chain tensioner and ultimately the driver's side valves which is obviously not related.

[kenikh]

The low end grunt is what I am most interested in. It seems that getting 300 HP from a small bore turbo is reasonable at a fair boost level. Since these motors don't have displacement to lean on for off boost torque, this lead to the question about bumping CR for drivability and throttle response.

BTW, found this little it on Eddie's motor:

Originally Posted by Turbo and High Tech Performance Magazine

The technology behind the e.t.s is impressive. The 1994 Porsche Turbo engine displaces 3.6 liters and shares component designs such as the crankshaft, rods and crankcase with its naturally aspirated brethren. Turbo specific pistons, cams and K-Jetronic fuel injection control team with two KKK turbos to produce 355 hp at 10 psi at the flywheel. Eddie's engine retains its 100mm bore but the stroke has gone from 76.4mm to 78mm and the compression has been dropped from 7.5:1 to 6.5:1. The engine's low compression pistons swing on custom Formula Monza titanium rods.

The evolution of the engine build-up program has spawned Bellotech, Eddie's performance shop that uses the lessons learned on the 1320 to tune street and race cars for NYC enthusiasts. Eddie put a good deal of time and effort into the cylinder heads knowing that the better they flowed, the better the engine would boost. The heads were port-matched, polished and opened up around the bowls, then fitted with 52 mm intake valves, 45 mm exhaust valves, titanium retainers and heavy-duty springs. Valvetrain events are under the direction of Elgin cams with .510 inches of duration on the intake side and .470 inches of lift on the exhaust side.

Pressurizing the meticulously prepped heads is a Bellotech turbo system. The system starts out with custom-fabricated exhaust manifolds with 1.75-inch primaries that each position one FasTrax T54 turbo. Three-inch intercooler pipe leads to air-to-liquid intercoolers featuring Spearco cores, then on to twin intake manifolds that Bellotech created in sheetmetal and then through custom 65 mm throttle bodies and into the combustion area. Boost is regulated by a Tial wastegate and Apex AVC-R boost controller.

Fueling the fire is a high-tech multi-stage injection set-up with 12 injectors falling under the control of a Haltech E6A computer. The Haltech name is certainly becoming popular as the E6-series box was the preferred choice on last month's cover car, along with many of the top Diamond Star racers we featured in that issue. Eddie uses his E6 to control 12 50-lb/hr injectors mounted on custom Bellotech rails. Four fuel pumps and two regulators use -8 lines to supply the go juice. Lighting the fire are three direct-fire MSD 7AL-2 boxes, an MSD coil, Vitek plug wires and NGK plugs.

On the Rampage Motorsports dyno in Queens, the pride of Stuttgart spun the rollers to the tune of 960 hp and 782 lbs-ft of torque. The dyno pulls were made with boost set at an eye-opening 30 psi. On the strip boost is regulated to a bit more conservative 20 psi. The Bellotech Porsche delivers power through a stock transmission with an RSR flywheel and Clutch Specialties clutch being the only upgrades.

[Reaper930]

Eddie is running over 33 lbs of boost on his aircooled motor he uses on the street. My motor was built for 1.6 bar and high rev's - so when it comes down to it as long as the hardware is in place to support the pressures you're asking it to contend with you shouldn't have an issue.

Agree on hopping on the phone with bello...he's one of the few who can really take you where you want to go with your mentioned setup.

But for me - i'm sticking with large displacement and standalone EMS with the old skool approach.

[930gt-40r]

There is a great thread in the engine building forum about this very subject

[juan ruiz]

Interesting Subject

I don't even know where to start. I guess that the first thing is that “WE" as a Porsche community were left behind in the aftermarket development of components regarding the parts to be able to make high output power out of our Porsche cars.

Boost in a 911 seems to be and still is a Taboo. I clearly remember in the early days of my build up when I was discourage from going over 1 bar of boost at time by some of the "Industry Porsche Gurus" almost 7 years later here we are running 35 pounds, over 75 1/4 passes, over 100 dyno runs and the engine still together, that has been accomplished due to some important facts.

Engine been properly build
Today’s high octane racing fuels
Today’s ECU and the ability to custom tailor a program that will work
Better and more efficient turbos
High quality of engine oils
Just to mention a few

What we have learn from other manufactures, people making stupid power with much smaller power plants, as mentioned Mitsu-Honda just to mention a few. Is that R&D that has allow us to “look outside the box” and been able to embark in the quest to make more power out of our engines; sure the engine configuration is different along with the castings but is been confirmed that our cars will make the power, not just my car or Bellos cars but people like Protomotive and most recently Titan a leader in the Supra world which has embarked into the Porsche high performance aftermarket business, so far clutches and ECU and soon we can expect some huge numbers from them.

Others like Chris Green an avid ¼ mile racer with a Jetta VW, he took his knowledge into a 997 on E85 fuel and the car is running 9.7s a truly street car and many more samples are out there.

The one important factor is the “Cost” if you stop and look at a fuel line for the 88 carreras at over $300.00 or even a cam front cover at over $300.00! Is the “P” luxury tag that has everyone reluctant to push forward to make more power, they are expensive and the many people capitalize on this.

“IF’ you are after the low end grunt, I said a small turbo with a gear change and you should be there, remember that with my original set up with the factory compression 9.5 bone stock engine with 56x on the odometer, single turbo, no intercooler non adjustable boost 0.5 (Which now seems like a joke) the car dyno 217 hp stock and ended with 320hp.

But that’s just my point of view.

[copbait73]

I see a disturbing pattern of raising C.R. on turbo engines. Raising compression is inversely proportional to power production on all turbocharged engines and any increase should be given serious consideration to the consequences.

The first and most obvious is detonation control on any combination of fluids injected into the cylinders. If you need off boost response get some gears, lose some weight, go twins or apply VNT. The engine will love you for it.

[Reaper930]

Originally Posted by juan ruiz

Interesting Subject

I don't even know where to start. I guess that the first thing is that “WE" as a Porsche community were left behind in the aftermarket development of components regarding the parts to be able to make high output power out of our Porsche cars.

Boost in a 911 seems to be and still is a Taboo. I clearly remember in the early days of my build up when I was discourage from going over 1 bar of boost at time by some of the "Industry Porsche Gurus" almost 7 years later here we are running 35 pounds, over 75 1/4 passes, over 100 dyno runs and the engine still together, that has been accomplished due to some important facts.

Engine been properly build
Today’s high octane racing fuels
Today’s ECU and the ability to custom tailor a program that will work
Better and more efficient turbos
High quality of engine oils
Just to mention a few

What we have learn from other manufactures, people making stupid power with much smaller power plants, as mentioned Mitsu-Honda just to mention a few. Is that R&D that has allow us to “look outside the box” and been able to embark in the quest to make more power out of our engines; sure the engine configuration is different along with the castings but is been confirmed that our cars will make the power, not just my car or Bellos cars but people like Protomotive and most recently Titan a leader in the Supra world which has embarked into the Porsche high performance aftermarket business, so far clutches and ECU and soon we can expect some huge numbers from them.

Others like Chris Green an avid ¼ mile racer with a Jetta VW, he took his knowledge into a 997 on E85 fuel and the car is running 9.7s a truly street car and many more samples are out there.

The one important factor is the “Cost” if you stop and look at a fuel line for the 88 carreras at over $300.00 or even a cam front cover at over $300.00! Is the “P” luxury tag that has everyone reluctant to push forward to make more power, they are expensive and the many people capitalize on this.

“IF’ you are after the low end grunt, I said a small turbo with a gear change and you should be there, remember that with my original set up with the factory compression 9.5 bone stock engine with 56x on the odometer, single turbo, no intercooler non adjustable boost 0.5 (Which now seems like a joke) the car dyno 217 hp stock and ended with 320hp.

But that’s just my point of view.

All I have to say is AMEN and thank God for EMS i'm moving to retune my motor to take full advantage of the upgrade in modern programming, larger maps and more control. I run 1.2 to the grocery store

[kenikh]

Glad to see there is experience in this area, after all. My reason for asking is that in pursuit of my 2.25L turbo build I have some new 9.5:1 JEs sitting around (and matching Nickies). I was going to buy new pistons until I started researching. This gives me the confidence to go ahead and try to build a 300HP 2.2L turbo w/ 9.5:1 pistons. If it fails to produce the desired results, I can always got to 8.5:1 later.

I will start the build in a few weeks, once I get my race prepped crank back from Marine...stay tuned. Now to source a pair of 50mm v-band Tial wastegates and an EMS...

BTW, what EMS do you guys prefer? Was thinking a customized MSII, but the Wolf v500 sure looks the business. Thoughts?

[kenikh]

BTW, it was also suggested by one of the Arizona Pelicans to add EMS controlled water spray into the cooling fan airstream for those really hot days. In the Southwest this apparently pretty common. Might be an interesting add on.

I wonder if the temp sensor would be better in the cooling fan or better to be driven off of a cylinder or cylinder head sensor. Thoughts?

I will say the slippery slope of adding water with a water to air IC, water to cool the turbo, water injection in the intake charge and water to the cooling fan air does pose some interesting philosophical questions, but I digress...

[930gt-40r]

Originally Posted by Reaper930

All I have to say is AMEN and thank God for EMS i'm moving to retune my motor to take full advantage of the upgrade in modern programming, larger maps and more control. I run 1.2 to the grocery store

Agreed- I think I would rather own a Corvette (all who know me know my feelings about these cars) than to keep deeling with CIS and the limits that go along with it.

[TimT]

BTW, what EMS do you guys prefer?

There are many good EFI systems on the market now, from low budget units like MSII or SDS to mega-buck MoTec, KMS, Bosch Motorsports, EFI Systems,Pi, etc.

We have been installing Haltech systems for over ten years and really like the Haltech ECUs. One tip is to find out what systems your dyno tuner is familiar with, that should carry some weight..

[juan ruiz]

Haltech systems

They must be real good thats what Bellos run, he has the dinosaur version

[DonE]

Originally Posted by juan ruiz

Haltech systems

They must be real good thats what Bellos run, he has the dinosaur version

Or he knows them and how they work. Thats a HUGE issue.

[930gt-40r]

Ive got an Accel DFI that I am looking to sell so I could get a new Haltech. The reason I want Haltech so bad is that I want to have more freedom with my ignition choices. The Accel is a great unit though- its reliable, simple, and has quality hardware.

[DonE]

If anyone is a hard core DIY person, you should narrow your ECU choices based on whatever criteria you want to use (like, are there others using it in the same capacity, does it have good mfg and dealer support, are there any local tuners/dynos that have experience with it), then download the software and take a look at it. Read the help files that come with it and compare. Does it have the flexibility you want? Does it have plenty of inputs and outputs (CHT, EGT, knock sensor, digital switching, boost controller, electric fan, etc), 4D ignition tables, 4D fuel tables and so on. And, can you understand it's logic (in case you buy it and have to make it work). It might help you make a decision on what ECU is right for you.

[strokher racing]

My advice to you would be to go to a real engine builder. I would recommend Mike at JB racing. My engine is there right now. When it comes out again some sparks will be flying. I would not go any higher than 8.1 if you plan to crank it up. My car has about as nasty of an intercooler on it as you can get. I have ambient intake temps after 5 back to back pulls on the dyno. That is with tap water. It is a massive air to water setup. With that being said I am only going 8.1.