Finally! Compressor Maps for K26, K27.2...
12-08-2003, 07:48 PM
#1
Three Wheelin'
Thread Starter
Finally! Compressor Maps for K26, K27.2...
I didn't think that compressor maps were available for the KKK K26 and K27 turbos used by Porsche, but I tracked down a reference to the April 1993 issue of Excellence. Andrew (Turbo944) was able to find the issue in his basement and scan in the article and compressor maps. 
He has kindly posted the entire article here:
Page 1
Page 2
Page 3
The K26 compressor used by Porsche (KKK 2670 GGA) is bigger than I had thought, with a maximum airflow of about 35 lb/min (500 cfm) and capable of a pressure ratio of about 2.7 (25 psi). In theory, it should indeed max. out at about 300 rwhp. The Garrett that is most equivalent is the T04E-40. Major differences are that it spins at a higher rpm to make boost, and it has a much narrower efficiency zone.
The K27 map in the article is the so-called K27.2 used on the 1986-1989 930, not the larger(?) K27-7200 used on the 964T. It is a big compressor, as expected on a 3.3 L turbo engine, with a maximum airflow of about 49 lb/min (715 cfm) and capable of a pressure ratio of 3 (29 psi.) In theory, it should be good for about 375 rwhp. The closest Garrett is the T-58, somewhere between the T04E-60 and the T61.
These maps should help settle some arguments about KKK versus Garrett compressors (no information on hot sides, though.) Thanks again, Andrew!
He has kindly posted the entire article here:Page 1
Page 2
Page 3
The K26 compressor used by Porsche (KKK 2670 GGA) is bigger than I had thought, with a maximum airflow of about 35 lb/min (500 cfm) and capable of a pressure ratio of about 2.7 (25 psi). In theory, it should indeed max. out at about 300 rwhp. The Garrett that is most equivalent is the T04E-40. Major differences are that it spins at a higher rpm to make boost, and it has a much narrower efficiency zone.
The K27 map in the article is the so-called K27.2 used on the 1986-1989 930, not the larger(?) K27-7200 used on the 964T. It is a big compressor, as expected on a 3.3 L turbo engine, with a maximum airflow of about 49 lb/min (715 cfm) and capable of a pressure ratio of 3 (29 psi.) In theory, it should be good for about 375 rwhp. The closest Garrett is the T-58, somewhere between the T04E-60 and the T61.
These maps should help settle some arguments about KKK versus Garrett compressors (no information on hot sides, though.) Thanks again, Andrew!
12-08-2003, 08:42 PM
#3
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Re: Finally! Compressor Maps for K26, K27.2...
Thank you both for taking the time to post this info. This article brings back some old memories...
The 86-89 930 came with the 3LDZ turbo some people call it a K27.
If you run the K26 at 25psi boost you will over-spin it and eventually destroy it...
The 86-89 930 came with the 3LDZ turbo some people call it a K27.
If you run the K26 at 25psi boost you will over-spin it and eventually destroy it...
Originally posted by Waterguy
The K27 map in the article is the so-called K27.2 used on the 1986-1989 930, not the larger(?) K27-7200 used on the 964T. It is a big compressor, as expected on a 3.3 L turbo engine, with a maximum airflow of about 49 lb/min (715 cfm) and capable of a pressure ratio of 3 (29 psi.) In theory, it should be good for about 375 rwhp. The closest Garrett is the T-58, somewhere between the T04E-60 and the T61.
The K27 map in the article is the so-called K27.2 used on the 1986-1989 930, not the larger(?) K27-7200 used on the 964T. It is a big compressor, as expected on a 3.3 L turbo engine, with a maximum airflow of about 49 lb/min (715 cfm) and capable of a pressure ratio of 3 (29 psi.) In theory, it should be good for about 375 rwhp. The closest Garrett is the T-58, somewhere between the T04E-60 and the T61.
12-08-2003, 10:40 PM
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“If you run the K26 at 25psi boost you will over-spin it and eventually destroy it...”
fast951
Are you speaking from experience? And what is the failure mode?
135k rpm does not seem excessive for a good turbocharger. I am planning to squeeze as much as possible out of the standard K26-6.
fast951
Are you speaking from experience? And what is the failure mode?
135k rpm does not seem excessive for a good turbocharger. I am planning to squeeze as much as possible out of the standard K26-6.
12-08-2003, 10:51 PM
#6
Waterguy
Thanks for posting that article.
And according to this article. 15psi is the sweet spot for the k26.
So a few more psi. like 17 or 18psi won't over shoot the good zones.
But the dreaded back pressure become the problem.
Does anybody know a good way to mesure back pressure in our cars.
Id like to try that with my car next summer.
Thanks for posting that article.
And according to this article. 15psi is the sweet spot for the k26.
So a few more psi. like 17 or 18psi won't over shoot the good zones.
But the dreaded back pressure become the problem.
Does anybody know a good way to mesure back pressure in our cars.
Id like to try that with my car next summer.
12-08-2003, 10:56 PM
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Originally posted by Laust Pedersen
“If you run the K26 at 25psi boost you will over-spin it and eventually destroy it...”
fast951
Are you speaking from experience? And what is the failure mode?
135k rpm does not seem excessive for a good turbocharger. I am planning to squeeze as much as possible out of the standard K26-6.
“If you run the K26 at 25psi boost you will over-spin it and eventually destroy it...”
fast951
Are you speaking from experience? And what is the failure mode?
135k rpm does not seem excessive for a good turbocharger. I am planning to squeeze as much as possible out of the standard K26-6.
The failure mode is the bearing going out much sooner. I never had it happen personally, however the KKK distributor has seen many of them fail for this reason..
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12-08-2003, 11:00 PM
#8
Three Wheelin'
Thread Starter
The 86-89 930 came with the 3LDZ turbo some people call it a K27.
The K27.2 turbo came (according to 3K/Borg-Warner) on the 91-92 964 C2T (3.3 L.) I am not sure if this is the same as a K27-7006. This is the turbo that Excellence provided the map for.
The K27-7200 turbo came on the 93-94 C2T (3.6 L.) This is a preferred upgrade for 930s. I had thought it was a larger turbo than the K27.2 since it came on the larger engine, but I did find a reference to using this turbo on the C2T for more mid to high end power. Apparently the K27-7200 spools much quicker than the 3LDZ (K26) or the K27-7006. Now I just have to find a compressor map for the K27-7200. Guess I will ask over at the 911 Turbo board. Or maybe Tony can remember from the old days....
Last edited by Waterguy; 12-09-2003 at 01:08 AM.
12-08-2003, 11:25 PM
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Originally posted by Waterguy
The 3LDZ turbo came on the 77-85 930 (3.0 L.) I have found it referred to on the 930 boards as "A K26 without water cooling."
The K27-7006 turbo came on the 86-89 930 (3.3 L.) KKK seems to refer to this as the K27.2 turbo. This is the turbo that Excellence provided the map for.
The K27-7200 turbo came on the C2T (3.6 L.) This is a preferred upgrade for 930s. I had thought it was a larger turbo than the K27-7006 since it came on the larger engine, but I did find a reference to using this turbo on the C2T for more mid to high end power. Apparently the K27-7200 spools much quicker than the 3LDZ (K26) or the K27-7006. Now I just have to find a compressor map for the K27-7200. Guess I will ask over at the 911 Turbo board. Or maybe Tony can remember from the old days....
The 3LDZ turbo came on the 77-85 930 (3.0 L.) I have found it referred to on the 930 boards as "A K26 without water cooling."
The K27-7006 turbo came on the 86-89 930 (3.3 L.) KKK seems to refer to this as the K27.2 turbo. This is the turbo that Excellence provided the map for.
The K27-7200 turbo came on the C2T (3.6 L.) This is a preferred upgrade for 930s. I had thought it was a larger turbo than the K27-7006 since it came on the larger engine, but I did find a reference to using this turbo on the C2T for more mid to high end power. Apparently the K27-7200 spools much quicker than the 3LDZ (K26) or the K27-7006. Now I just have to find a compressor map for the K27-7200. Guess I will ask over at the 911 Turbo board. Or maybe Tony can remember from the old days....
The first K27-7200 was used on the C2T 1991-1994 (1994 had a 3.6L vs. 3.3L)
If you do come across a K27-7200 map please email me a copy. It's an upgrade i plan for my personal 930.
12-09-2003, 12:31 AM
#11
Three Wheelin'
Thread Starter
Thanks, John, I have edited my post. Combination of going by memory and relying on info sources that may not be accurate. I was going to ask you about the 1928 930!
I got the part numbers from bramall-turbo.com, which show the K27-7006 part number from 83-89. Of course, the show the C2T having a 3.6 L engine from 89 on, when it wasn't built till 91 and got the 3.6 L in 1993, as you say.
Can I assume from your reply that you are 'one of the guys' on the 911 turbo board, and that I am not going to find a map for the K27-7200 over there? Do you have any information on size/flow/spool characteristics of the K27-7200 relative to the K27-7006 which we have the map of?
I got the part numbers from bramall-turbo.com, which show the K27-7006 part number from 83-89. Of course, the show the C2T having a 3.6 L engine from 89 on, when it wasn't built till 91 and got the 3.6 L in 1993, as you say.
Can I assume from your reply that you are 'one of the guys' on the 911 turbo board, and that I am not going to find a map for the K27-7200 over there? Do you have any information on size/flow/spool characteristics of the K27-7200 relative to the K27-7006 which we have the map of?
12-09-2003, 02:54 PM
#12
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Hmm.... It seems like the Baby K26/6 is alot bigger than I thought. If a K26 is equivalent to a T04E 40 trim, then why is so much power gained when upgrading to even a T04E 46 trim?
Maybe the real power adder for us with Garett Turbos is in the Machininng of the turbine housing out to close to the Specs of a #8 Hot housing. So its a minor Compressor upgrade, a Substantial Turbine/housing port, and brand new bearings in the center section that gives us all the power.
Maybe the real power adder for us with Garett Turbos is in the Machininng of the turbine housing out to close to the Specs of a #8 Hot housing. So its a minor Compressor upgrade, a Substantial Turbine/housing port, and brand new bearings in the center section that gives us all the power.
12-09-2003, 03:08 PM
#13
Three Wheelin'
Thread Starter
Yeah, within the limits of compressor efficiency, boost is boost. 15 psi will get you x horsepower at a certain volumetric efficiency (compressor efficiency is largely cancelled out by intercooling, again within the limits of the intercooler.) However, the K26 compressor must turn at higher rpm to generate the same level of boostas a Garrett, probably contributing to turbo lag. Also, the T04E-46, -50, -60 etc. have higher maximum flow rates than the K26, so won't run out of air at 280-300 rwhp.
I think the turbine side must be more important. Turbine backpressure reduces volumetric efficiency, so lowered backpressure increases horsepower at a given boost. (For example, I think TonyG must be going for VE > 100% to get 400 rwhp out of a 2.5 L at 15 psi.)
What about Garrett/KKK hybrids; do you get the same benefits as a straight Garrett? Or do you lose benefits due to the KKK hot side?
I think the turbine side must be more important. Turbine backpressure reduces volumetric efficiency, so lowered backpressure increases horsepower at a given boost. (For example, I think TonyG must be going for VE > 100% to get 400 rwhp out of a 2.5 L at 15 psi.)
What about Garrett/KKK hybrids; do you get the same benefits as a straight Garrett? Or do you lose benefits due to the KKK hot side?
12-09-2003, 07:40 PM
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"What about Garrett/KKK hybrids; do you get the same benefits as a straight Garrett? Or do you lose benefits due to the KKK hot side?"
I think this is what my "mystery" turbo might be.
* Same size as K26
* Full boost about 3.4-3.5K
* No markings on compressor side, but KKK stamp on hotside
* 2.75 inch inlet, as opposed to 2.25 stock
* Holds and pulls full 15+ psi to redline with out running out of steam.
I think this is what my "mystery" turbo might be.
* Same size as K26
* Full boost about 3.4-3.5K
* No markings on compressor side, but KKK stamp on hotside
* 2.75 inch inlet, as opposed to 2.25 stock
* Holds and pulls full 15+ psi to redline with out running out of steam.
12-10-2003, 12:01 AM
#15
From the information and mesuring i did last year.
A k26 is equivalent to a T3/50 trim
First by the actual size of the compressor wheel.
Second by comparing the mapsT3-50 Trim
And a K27, if we just look at the maps. Its Garrett equivalent would be closer to a T04E-40 Trim
But that just from comparing both K27 & T04E-40 Map at a few places.
Like 2.0 PR & 0.2 (20) flow they both end up arround the middle of the max efficiancy. Or like at 3.0PR & 0.3 (30) flow the T04E-40 out flow the K27 by 5% effic.
So Even a T04E-40 out flow the K27.
Does anybody have the actual size of the K27 compressor wheel? That way we could compare its actual size to the Garrett wheels.
But that just my fast conclusion.
A k26 is equivalent to a T3/50 trim
First by the actual size of the compressor wheel.
Second by comparing the mapsT3-50 Trim
And a K27, if we just look at the maps. Its Garrett equivalent would be closer to a T04E-40 Trim
But that just from comparing both K27 & T04E-40 Map at a few places.
Like 2.0 PR & 0.2 (20) flow they both end up arround the middle of the max efficiancy. Or like at 3.0PR & 0.3 (30) flow the T04E-40 out flow the K27 by 5% effic.
So Even a T04E-40 out flow the K27.
Does anybody have the actual size of the K27 compressor wheel? That way we could compare its actual size to the Garrett wheels.
But that just my fast conclusion.
