Question for Wyd (or others) re gt35

[WydRyd]

930gt-40r, the Proto setup works great and is a simple and cheap solution for aftermarket turbocharging a naturally aspirated engine. Otherwise you're up for serious $$$$ for aftermarket standalone EFI. I only run the Proto Stage 3 CHIP and dual rate fuel pressure regulator on my existing setup, but eventually I will swap out my OEM ECU for the Proto Motronic MAP Sensing ECU, which is a more refined solution and still cheaper than an aftermarket Motec/Autronic setup. Just drops in place of the OEM ECU, uses existing loom and just requires a vacuum line run and a IAT & TPS sensor mounted to the throttle body. For the 993's, Proto has a variety of TT conversions/kits, so get in contact with them. I'd say you can single turbo a 993, but lumbing might be easier with the twin setup, because of the twin distributor in the path of charge air pipe in a single turbo setup. Speak to Todd Knighton.

[930gt-40r]

That sounds mint, I would just go for the pressure sensing first. Your right, twins may be more managable. I am wondering if it would still work with obd 2 and still pass emissions. This project I speak of would not be happening for a long time, but it is still fun to think about.
What is the diff. between stage 3 and pressure sensing? is it just the use of a mass air and no tps mod?

[WydRyd]

Originally posted by Frank@AMS
Merv,

While I do agree that a GT30R would spool up sooner, Garret does not make a T4 hot side GT30R. I can most likely get one specially machined, but at the same time, the turbo would really run out of breath in the top end.

When Yermancars converted to the smaller turbo he is running now, there was a small loss in power however, it spooled up so much sooner, and the power band expanded. The car felt quite a bit faster than before, even though its down a few horsepower from the GT40.

Also, the ball bearing turbos are nice, however, you will have to run and extra oil line through the water passages.
Standard journal bearing turbos, with updated housings, are a better way to go with the air cooled boxer motor in my opinion.

Frank, Greg's original posts suggested he was after a LOW BOOST setup on a naturally aspirated motor, so I'd assume he's looking at running only about 0.7bar. The GT30R would suit that application nicely and not run out of breathe up top. It's rated to 500HP and a 0.7bar bolt on setup on a 3.2 would yield ~400HP. BTDT

Also, I run my GT35R oil cooled only. I left the water passages open. I use a -3AN oil feed, NO RESTRICTOR (as advised by Garrett dealer) and drain to the oil sump plug. I've had no problems to date, however, it's only been on my car for a couple months now. Time will tell. The key to making these live is to exercise proper cool-down procedure and to keep the oil clean and fresh.

The idle oil pressure on 911 engines is relatively low (~1.5bar) compared to Japanese cars, which is why the Garrett dealer suggested no restrictor is used. Also, oil pressure does not exceed 70psi under load, so that's another reason why they suggested no restrictor.

The turbo will let you know if a restrictor is required or not as it'd start leaking oil and smoking. Mine's been fine

[Frank@AMS]

Merv,

The coolant passages are used to cool the bearings on the turbo, Id
personally recommend at least running oil through those. As far as the GT30 being rated to 500HP, boost threshold on the turbo becomes far more apparent on a high liter car. For example, here at our shop we can run 30psi through the GT30R, at that point it stops making power on our 2.0 liter motors. On a Porsche motor, the T3 hotside would be way to restrictive even at 1.0bar of boost. There are just too many liters to fill will such a small cfm rating.

[WydRyd]

Originally posted by 930gt-40r
What is the diff. between stage 3 and pressure sensing? is it just the use of a mass air and no tps mod?

Stage3 is just the engine build spec and associated power level. Has nothing to do with the type of engine management solution used.

My Stage3 still uses the OEM BOSCH AFM setup, which works OK, but I'd rather have the MAP Sensing setup in a heart-beat. At ~USD$2.2k, it's a great deal (compared to Motec/Autronic setup etc).

Their MAP ECU comes preprogrammed with a map to get you running asap. Apparently it's pretty accurate and may need minor adjustments for your application. To get things sport on, Todd will re-program your maps for you and send the binary image to you via e-mail for you to burn on EPROM and try in your ECU. All you do is supply him AFR's plotted against boost/load/rpm and he'll do the fine adjustments as deemed necessary.

A few guys over on Rennlist run the Proto TT setup with MAP Sensing ECU and they have only positive things to say about it! I can't wait to get it myself People typically say "the car is totally transformed and it feels like the engine has been swapped out with a BIG naturally aspirated motor".

[WydRyd]

Originally posted by Frank@AMS
Merv,

The coolant passages are used to cool the bearings on the turbo, Id
personally recommend at least running oil through those. As far as the GT30 being rated to 500HP, boost threshold on the turbo becomes far more apparent on a high liter car. For example, here at our shop we can run 30psi through the GT30R, at that point it stops making power on our 2.0 liter motors. On a Porsche motor, the T3 hotside would be way to restrictive even at 1.0bar of boost. There are just too many liters to fill will such a small cfm rating.

Frank, I also have heard of people running oil through the water passages, but these are for track cars which see sustained peak loads and boost. For a street car (like mine) which sees occassional full boost, I think I'm quite safe to leave those passages open. If I were building a car for street and track, I'd definitely run oil through those passages. Good point!

BTW, don't the K27-7200, K27-HFS & HF2 turbos run a T3 hotside?

[Frank@AMS]

Merv,

The K27's do run a T3 hotside but, notice how all the 930 guys always complain how power drops off in the upper rpms

[WydRyd]

I thought that was the result of the compressor not being very efficient up top? Interesting!

Anyway, I only run my baby to 1.1-1.15bar MAX, and the GT35R I have maintains HP all the way to redline. I'm happy

[Porschefile]

Originally posted by WydRyd
I thought that was the result of the compressor not being very efficient up top? Interesting!

Anyway, I only run my baby to 1.1-1.15bar MAX, and the GT35R I have maintains HP all the way to redline. I'm happy

Properly sizing the turbine and hotside seems to be a topic that is often overlooked.

[WydRyd]

It's also interesting that all the aftermarket header manufacturers build their headers with T3 flanges (GHL, B&B, GSF, Schnell etc), except for fabricators like Marco Menzie and Bob Holcomb. I guess all the off-the-shelf stuff are design to be as bolt-on as possible, whereas MM & BH build their headers for big HP aftermarket applications.

I agree though... for a 3.3, 0.81/0.82 A/R seems to be the best sizing for good power and response. I went with 0.78 A/R because I wanted the divided inlet turbine housing to bolt right onto the GSF headers. Divided inlet housings are suppose to offer slightly improved spool-up too, I've read.

[930gt-40r]

I wanted to do the whole bosch injection sys with pressure sensing, but after buying the plenum, harness, and software it would come out to almost 5 grand which is right know out of my reach. I would love to do it but I guess my accel dfi will have to due for now. Im sure it could be tuned to run close to the bosch/protomotive setup, but there is something about having the stock porsche designed part-throttle curves and map sensing that makes my pulse raise.

[Porschefile]

Originally posted by 930gt-40r
I wanted to do the whole bosch injection sys with pressure sensing, but after buying the plenum, harness, and software it would come out to almost 5 grand which is right know out of my reach. I would love to do it but I guess my accel dfi will have to due for now. Im sure it could be tuned to run close to the bosch/protomotive setup, but there is something about having the stock porsche designed part-throttle curves and map sensing that makes my pulse raise.

With a decent, modern aftermarket EMS, you can tune ALL engine parameters for these motors (and pretty much any older motor/setup for that matter) to only run better than stock by someone that truly knows what they are doing. Aftermarket EMS gets a bad wrap because it can be very complicated to deal with and very easy to get wrong. Most modern aftermarket EMS' (except maybe SDS or some of the really simplistic ones) have superior software and superior hardware componentry compared to the stock Motronic, plus lots of advanced features that will generally increase efficiency and performance.

Wydryd, divided housings do definitely aid in spoolup. It's really fairly simple actually. You are dividing the total surface area and adding a slight restriction, which has the effect of increasing exhaust flow velocity. Quicker velocity means quicker spooling. It's much the same basic concept that people use when porting heads. Also, depending on the exact setup, with divided housings you can also take advantage of pulse tuning by grouping the proper cylinder pulses into 2 separate runners that stay separate all the way to the exhaust housing. To give a general example, all I4's have a 1-3-4-2 firing order. You'd group cylinders 1&3 into one runner and 4&2 into another runner and keep them separate all the way to the turbo. Generally, from what I've seen this tends to have more of an effect in shorter manifold designs like you'd find on a compact I4. On F6's, our headers are generally a decent amount longer so I doubt if you'd notice much effect if any. Running the divided housing alone is all that would really be necessary.

[Porschefile]

Wydryd, if you don't mind me asking, I was curious where your boost threshold is and what rpm you are seeing full boost at? I'm thinking of doing a Gt4088r w/ a .85 T4 hotside. It's the same compressor as a 35r, basically just an anti-surge housing and larger turbine/hotside than the 35r. Judging by what I've seen on other similar displacement motors (3-3.5l i6's, v6's, etc) I'm thinking I should see 1 bar around ~3.8-4k rpm which is good enough for me.

[Frank@AMS]

Porschefile

If you already running a T4 hot side, there is no need to run a .85 hot side. You would easily be able to run somewhere around a .65 without seeing any drop off in higher rpm efficiency while gaining spool time.

[YermanCars]

Originally posted by Porschefile
Wydryd, if you don't mind me asking, I was curious where your boost threshold is and what rpm you are seeing full boost at? I'm thinking of doing a Gt4088r w/ a .85 T4 hotside. It's the same compressor as a 35r, basically just an anti-surge housing and larger turbine/hotside than the 35r. Judging by what I've seen on other similar displacement motors (3-3.5l i6's, v6's, etc) I'm thinking I should see 1 bar around ~3.8-4k rpm which is good enough for me.

What kind of power are you looking for.

[Porschefile]

I'm running a .81 T4 hotside at the moment. Frank, the thing is the 40r .85 hotside is a twin scroll, so that will aid spool a bit. Also, from what I understand there are some internal differences (other than the twin scroll setup) that make the .85 GT housing different from a regular .81 T4 housing. Since the 40r comes with the hotside, I might as well use it. Ultimately I'd like to break ~600whp. Judging by what I've seen, for that size of compressor/turbine, a .68 housing is going to be pretty restrictive around the 600whp level, and I'd like to accomplish that without running too much boost. A gt40r is similar in size to a T4 T66, so it's not really that large of a turbo for a 3.4l. It would make reaching 600whp much easier and I'd be able to accomplish it at lower boost while still not being that laggy.

[YermanCars]

Modified gt37 @ 16 psi, running the afm and motronics. Heat soaked intercooler, could of made 25rwhp more.

Frank is dynoing the car.

http://media.ams-evo8.com/videos/amsmisc/PorscheDynoRun.wmv

600rwhp no problem w/ 20psi, maybe 18psi w/ a good tune, full spool @ 3600 rpms.

[WydRyd]

Originally posted by Porschefile
Wydryd, if you don't mind me asking, I was curious where your boost threshold is and what rpm you are seeing full boost at?

Porschefile, if I punch the throttle, I can get full boost at ~3K... it spools very quick, just the way I like it. It may have to do with the 0.78 A/R divided inlet housing, not sure? I'm sure the bigger A/R housings would result in more top end HP, but I wanted it purely for street as my car is my daily driver, so I wanted something snappy on the road and that's what the GT35R delivered. I'm pleased. Once I sort out my twin plugging, it'd be even more responsive

I've heard reports of the GT35R spooling up as low as 2700rpm on a finely tuned motor with aftermarket engine management, pressure sensing, twin plugs etc...

[Porschefile]

Originally posted by WydRyd
Porschefile, if I punch the throttle, I can get full boost at ~3K... it spools very quick, just the way I like it. It may have to do with the 0.78 A/R divided inlet housing, not sure? I'm sure the bigger A/R housings would result in more top end HP, but I wanted it purely for street as my car is my daily driver, so I wanted something snappy on the road and that's what the GT35R delivered. I'm pleased. Once I sort out my twin plugging, it'd be even more responsive

I've heard reports of the GT35R spooling up as low as 2700rpm on a finely tuned motor with aftermarket engine management, pressure sensing, twin plugs etc...

Twin scroll housings do make turbos spool more quickly. Ultimately it's really simplistic in that they divide the total surface area of the inlet which has the effect of increasing airflow velocity and increased velocity = quicker spool. Depending on the exact turbo setup, you can couple this with pulse tuning to improve spool as well. All that means is you'd combine the proper exhaust runners to form two separate runners that stay completely separate all the way to the exhaust housing. For example, on a i4 you'd mate #1 and #3 together and you'd also group #2 and #4 together, though you'd keep each pair separate from the other pair. I hope that makes sense. I have some suspicions that simply running a divided turbo flange alone should provide 80-90% or more of the benefits of increased spool on most setups. Maybe on a motor with much shorter runners, like the typical i4 turbo setup, you might see benefits from pulse tuning a twin scroll setup (due to possible elimination of exhaust flow turbulence) though motors like 930's have decently long runners so I'm wondering if the divided flange alone is just "good enough" if you catch my drift. I'm sure Frank has much more hands on experience in this arena, so maybe he might be able to say for sure.

Personally, I'd say technically .78 divided T3 housing is a bit small considering your displacement, and a T4 housing should have some nice improvements in power however it sounds like it works perfect for your needs, and in the end that's all that really matters. Personally, I like a higher boost threshold of say anywhere around 3.5-4.5k for full boost. I don't mind the loss of some off-boost performance, and I prefer a powerband that flows plenty up top and holds torque/hp at least above 6-6.5k rpm before dropping off. I'll be going with Gt2 Evo cams and stiffer springs to support ~7.5-8k rpm so I don't mind a bit more lag. The increased rpm is part of the reason I'm considering a larger turbo like the Gt4088r or possibly even the new Gt4094r (kind of a 40r/42r hybrid, about the size of a T4 T66). Either one of those should make full boost in the 3.8-4.5k range and no later, though they would both allow me to reach 600whp with quite a bit less boost than a 35r.

[al clark]

Could some one tell me if i would see much power increase on a stock 3.3 by going from a stock KKK27 to a hybred KKK28 with a KKK27 hot side KKK28 center section and KKK29 compressor side? Also would it be a bolt on or would mod.have to be made to install on 92 turbo? THANKS