Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Gt30-76r

Was playing on the Garrett web site and found that there is a larger version of the GT30 that looks like it might be something to consider for a CIS 930.

It also has three different AR hot sides so one can tune where there boost comes on. I wonder if it might just fit in well just above the K27-7200 or 7600.

Comparative compressor sizes:

53.1mm = Gt-30's except the 76R.

54mm = K27-7200 & 7006

56mm = new UMW K27 HySpool

57mm - GT30-76R

60.5 = HF

61.4= GT35



Details here:
TurboByGarrett.com - Catalog


Last edited by 911st; 10-23-2010 at 05:20 PM.. Reason: Restate point more clearly.
Old 10-12-2010, 07:23 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered
 
Join Date: May 2003
Location: Woodlands TX
Posts: 2,826
I really dont know much about turbo compressor maps and the engineering details or matching flow rates.

However I have been in a 2.5 l subaru with the bigger gt30r and it spools pretty damn fast in that little 4 banger. Granted that car has variable valve timing efi and all the fun modern controls. However it the 3.3l l porsche motor can spool it nearly as fast it would be a great match. I think the subie made about 380whp with its AWD losses so figure 450+ at the crank.
__________________
84 930
07 Exige S
Old 10-12-2010, 07:58 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
R.I.P.
 
drmatera's Avatar
 
Join Date: Aug 2009
Location: Nicholson, Ga
Posts: 2,160
Buddy of mine just made 460rwhp @ 27psi in his Evo 8 with that turbo. Its ball bearing and spins if the wind blows. Considered it for my car but was told its too small. Bet it would spool super quick on a 3.3
Old 10-12-2010, 08:54 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered
 
930gt-40r's Avatar
 
Join Date: Jan 2007
Location: Boca Raton, FL
Posts: 2,066
Garage
For a CIS car it would likely be a great turbo. I also believe that if you call garret, they will size up a compressor wheel to fit your needs. Or maybe it is Precision or HKS that I am thinking about. But in any event, the 3076R is a solid turbo, but I think that the outer limits of a CIS car may be pushing it for that turbo at 1bar or 1.2 bar...
__________________
Kris @ Tech9
86' 930/GT-40R Sold
94' Rustang GT daily (long gone)
2008 C6/Z51 Corvette
Old 10-13-2010, 06:39 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
drmatera,

The stock K27-7200 has about a 54mm compressor, your turbo I think is almost a 62mm compressor and this one has a 57mm compressor so it should be between the two.

A bigger turbo on your car was probably a better idea with your conversion to EFI.

CIS has something like 5 to 6 feet of plumping and the metering plate pushing against air flow adding restriction and pressure drop before the turbo's intake. With EFI this is greatly reduced allowing even a larger turbo to spin up faster.

I suspect the larger compressor we put with CIS the slower it really wants to respond. The makes the time from boost onset to full boost longer.

Kind of like someone saying that going from 23" wheels to 25" wheels on a car is going to make you go faster. In some cases it might but it will take longer to get there.

Or it will take more power to get you there at the same time. This would be seen as more back pressure against the turbine.

Again, this is my thinking and the more I learn the less I seem to know.
Old 10-13-2010, 08:12 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Kris,

Good point. On a max build it would probably put this turbo out of its peak efficiency island. Such a build would require cams, increased fueling and probably larger ports and all the other tricks. Thus, a GT 35 or such is probably a better match.

This is more for the CIS build that is not after that last 50hp. As such this might make gains in response and efficiency over a larger turbo. I had an HF with its small turbine and large compressor. It is a good upgrade and comes in like a V8 in a very controlled way. I more preferred the fast and hard spool of a smaller turbo but that was me. I suspect for most CIS 930's this turbo will get both the low end kick and carry full boost to red line.

Again, I think of it more like a better K27-7006 than steeping up to a K29, HF, or GT35. Some of the gain is probably going to be from a more efficient hot side on the GT30-76R.

Add to that the lower mass, ball bearing construction and it should be a much quicker spool turbo.

Another plus is we can play with the turbine's AR sizes to tailor one's goals. With the K27 turbos that is not as easy to do.

I believe drmatera found access to being able to tune the hot side very valuable with his turbo.

As a point of reference, the 7200 and 7006 have very, very close to the same size compressor wheels, it seems it is the 7006's larger turbine that lets it make more power. I have often heard there is great opportunity on the hot side.

I truly suspect the 7200's turbine was designed intentionally to choke off the turbo so air flow would not exceed the 3.3 turbo's fueling limits to a large degree. It is never allowed to reach the higher air flow parts of its compressor map. I could be wrong but that is what the information suggests to me. The 7006 keeps making boost with basically the same size compressor wheel.

Last edited by 911st; 10-13-2010 at 08:39 AM..
Old 10-13-2010, 08:37 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Came across this post by the man that probably sold more small compressor large compressor K27 hybrids than anyone.

Quote:
Originally Posted by Porschephd View Post
Been forever since I drove a 7200 daily
I have to tell you it hits hard and fast, but hell...I also forgot how hard it is if not impossible to keep a bar on a 3.6 after 5300ish. It is impossible. Pain in the ass really. I need a job so I can change it over to a Garrett. Oh the CIS you ask....well I am not ditching it and will have a solution (hopefully) to maintain the likes of a GT35 with it...Great turbo as long as you are A)ok with short powerband and B) on a smaller displacement motor.
This is what I am after. The kick of a 7200 or better but just enough compressor to carry the top end on most modified 3.3 CIS turbos.
Old 10-13-2010, 09:02 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
R.I.P.
 
drmatera's Avatar
 
Join Date: Aug 2009
Location: Nicholson, Ga
Posts: 2,160
I was told to size the exhaust wheel for the power you want to make then size the exhaust housing a/r for when you want boost in the rpm range..

I have run both the .70 a/r and the .55 on the dyno. Same wastegate settings yeilded peak boost about 700rpm sooner with the .55 with no sacrifice in power at 6000rpm. I took it to 6200 on one pull but my gut chickened out before the power dropped.
Old 10-13-2010, 09:11 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
I wish we would start checking the back pressure with different turbos. This is such a basic concept.

This post talks about ballanceing the hot and cold side and suggests that there is significant opertunity on the hot side. And that it is not alwas a small turbine that makes for the quickest boost. Nor is it the bigest that makes the most HP.

Quote:
Originally Posted by TurboKraft View Post

...Long story short, the engineers at Garrett (and BorgWarner, etc.) have the tools to refine their products very well before putting them into production. They don't match one compressor wheel to a different turbine wheel by chance or accident. They look at the airflow characteristics and inertia of the components and put together the best combinations. Rarely will you find a manufacturer's turbo with a compressor wheel that radically out-flows the turbine wheel, as you often find in the aftermarket. (And these are usually targeted for small displacement, high boost, high HP engines that also run massive wastegates to make up for the lack of turbine flow.)
That's not a 930 engine's m.o.

One result of this mis-matching is higher exhaust backpressure at the turbine inlet (header) flange. 930s are bad enough, and the long, undersized tube feeding the wastegate on most aftermarket headers doesn't help matters, either.
Anyone else have exhaust backpressure data they would like to share?
We just dyno tuned an ex-Ruf 3.4L that had been in storage for many, many years. Another shop converted it to EFI and "600hp" -- not with a K29-7006#13, buddy! At 17.2psi boost in the manifold, the exhaust backpressure was just a hair under 30psi. About a 1.75:1 pressure ratio (backpressure:boost) despite the larger #13 turbine housing. Car is choking on the backpressure, spooling up slowly, keeping the Group B cams from doing their work.
One of the most responsive EFI 1994 Turbo 3.6s we have built had 2 different large ball bearing turbos. The first had a 1.4:1 backpressure ratio and drove great. The next turbo we used had a lower 1.2:1 ratio from a significantly larger turbine wheel -- and it spooled up even sooner than the smaller turbo! ...
Old 10-13-2010, 09:24 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Here is the compressor map for the K27-7200 and the GT30-76R:

Looking at the 2 bar line at 40lb/min both seem to be about 75% efficiency.

To me it dose not really look like the largest GT30 has any major advantage on the cold side over a 7200. It's magic would have to be in the ball bearing construction and the possibility of better flow potential on the hot side.

Again, probably more like a BB 7006.







I am thinking that for .8 bar boost with our restrictive CIS intake plumbing we should be reading the 2.0 line. For 1 bar the 2.2 line.
Old 10-13-2010, 09:40 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
R.I.P.
 
drmatera's Avatar
 
Join Date: Aug 2009
Location: Nicholson, Ga
Posts: 2,160
you will notice most all the turbocharging books refer to the "exhaust wheel" and not so much the housing. As I mentioned above:

wheel size = flow
housing a/r = rpm range
Old 10-13-2010, 09:40 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Right on!

With in a range, what might be better. A larger wheel with a smaller AR or a smaller wheel with a larger AR?
I wonder.
Old 10-13-2010, 09:44 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Quote:
Originally Posted by drmatera View Post
...I have run both the .70 a/r and the .55 on the dyno. Same wastegate settings yeilded peak boost about 700rpm sooner with the .55 with no sacrifice in power at 6000rpm. I took it to 6200 on one pull but my gut chickened out before the power dropped.
Wow, that is a big difference.

Would be interesting to see if there is a differance in peak HP or HP at say 6000rpm between the two. If the smaller AR is making much less HP then this might indicate the exhaust is building more pressure in place of testing back pressure at the header.
Old 10-13-2010, 09:53 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #13 (permalink)
R.I.P.
 
drmatera's Avatar
 
Join Date: Aug 2009
Location: Nicholson, Ga
Posts: 2,160
Quote:
Originally Posted by 911st View Post
Right on!

With in a range, what might be better. A larger wheel with a smaller AR or a smaller wheel with a larger AR?
I wonder.
I asked a few turbo gurus that very question. Overall to get an efficient turbo you must match the exhaust wheel with the compressor wheel. Then you match the housing to the "power range" of the engine. It seems a typical 3.3 930 engine likes the 3500-6000rpm range. If your turbo doesn't reach full boost till 4500 you have lost power under the curve and left a ton of usable power on the table. Who cares if it flows to 7500rpm, your engine won't
Old 10-13-2010, 10:07 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #14 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Here is a good point of reference.

I do believe the 3.3 CIS gets very happy with about a 60mm compressor wheel.

I think I like the HF a little more now that I know this.

Quote:
Originally Posted by Zeroclearance View Post
Merv, your supplier might have told you that.. However, since I MAKE the Hyflow series, the Hyflow has a 60.5mm compressor wheel the GT35 has a 60.85mm compressor wheel. The compressor wheel in the Hyflow is more efficient.

Your engine has been reconfigured, you would have been surprised at the numbers that the Hyflow would have rung out with the new changes to your engine package.

Last edited by 911st; 10-13-2010 at 10:18 AM..
Old 10-13-2010, 10:12 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #15 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
It looks like the designer of the HF on his 3.3 CIS turbo has added a larger hot side wheel from a 7006 but with a smaller AR.

This would probably lower header pressure and get the hot to cold wheels ratio back closer to what BW/KKK usally built.

Quote:
Originally Posted by Zeroclearance View Post
The advantage of the larger compressor wheel is> you get more "air" available for the engine to run to redline vs falling on it's face around 5200RPM's plus or minus. On my 965 I have a rare hybrid 7006.. Rare meaning>> 9 cm/2 turbine housing with the large 7006 turbine wheel and massive compressor wheel.

It is far easier to free up the 7200 vs finding/casting a smaller A/R housing for the 7006.. It took me 4 years to get my hands on the 9cm/2 housing. With that said the 7200 does spool up quicker.
Old 10-13-2010, 10:17 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #16 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
This guy's success has long been a good point of referance to me that a 3.3 CIS can get very happy with a 60mm compressor. It is also might be seen as a good argument for proper hot side sizing and ball bearing center section. Note this is only a single BB turbo. The GT's are dual BB.

Quote:
Originally Posted by MarkRobinson View Post
stock cams: stock engine, stock WUR.

Car made 247/267 stock (rear wheel HP/TQ).

Added the B&B system: 267/287rw

Raised boost to 1.0 bar via factory K27: 315/335

Tried a number of K27/TD04 Variants, 355/355 was the average, but the 60-1 SBB made a huge differennce in top-end power & spool up (torque came in like 800rpm sooner with the DBB) over the bushed 60-1 before then.

Went from the bushed 60-1 to a SBB 60-1, rwtq increased from 150rwtq @ 3k to 300rwtq @ 3k: huge streetablity increase: which is why I dismissed spending the dime on cams.
Old 10-13-2010, 10:24 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #17 (permalink)
R.I.P.
 
drmatera's Avatar
 
Join Date: Aug 2009
Location: Nicholson, Ga
Posts: 2,160
wow, if he is seeing 300rwtq @ 3k rpm thats pretty impressive. I just looked at my dyno sheet, i'm at 280rwtq @ 3k rpm and I thought that was quick spool up. But it does seem to matter what rpm you start the run at.
Old 10-13-2010, 11:24 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #18 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Quote is from Garrett's turbo tech section about ball bearing center section.

There is still the mass of the turbo's rotating parts, the turbine exducer to the compressor's inducer ratio, and the sizing of the hot side to consider among other things.

Quote:
Turbo Response When driving a vehicle with the cartridge ball bearing turbocharger, you will find exceptionally crisp and strong throttle response. Garrett Ball Bearing turbochargers spool up 15% faster than traditional journal bearings. This produces an improved response that can be converted to quicker 0-60 mph speed. In fact, some professional drivers of Garrett ball-bearing turbocharged engines report that they feel like they are driving a big, normally aspirated engine.
Old 10-13-2010, 03:53 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #19 (permalink)
R.I.P.
 
drmatera's Avatar
 
Join Date: Aug 2009
Location: Nicholson, Ga
Posts: 2,160
well, it looks like the Gt3076 would be a pretty good turbo on a stock 3.3 motor. The comp map says it will get just over 500hp before running out of breath. My buddies 2.0L Evo motor spools quick I could only imagine this thing

Old 10-20-2010, 08:02 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #20 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 11:39 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2020 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.