Tony G, KKK K27, and me
11-22-2003, 10:20 PM
#1
Race Director
Thread Starter
Tony G, KKK K27, and me
Tony,
You are clearly the man for this job! I have a stock k26/6. I am looking to develop a k27/6 or 8 or slightly bored out hotside. I really need advice on wheel specs to get and more technical specifications on the work. Tuners here have no idea, so I need as much help as possible! You can see my mods below if it helps. I would like a quick spool street turbo, 0-100 stuff... can you help?
Warm regards,
Andrew
You are clearly the man for this job! I have a stock k26/6. I am looking to develop a k27/6 or 8 or slightly bored out hotside. I really need advice on wheel specs to get and more technical specifications on the work. Tuners here have no idea, so I need as much help as possible! You can see my mods below if it helps. I would like a quick spool street turbo, 0-100 stuff... can you help?
Warm regards,
Andrew
11-23-2003, 12:44 PM
#2
Rennlist Junkie Forever
NZ951
What do you mean wheel specs? There's not much to develop out. The K27/6 turbo combo has been used for well over 10 years now.
Send your turbo into a turbo shop and have it converted with a K27-7200 compressor housing and wheel. All the rest of your turbo remains stock.
TonyG
What do you mean wheel specs? There's not much to develop out. The K27/6 turbo combo has been used for well over 10 years now.
Send your turbo into a turbo shop and have it converted with a K27-7200 compressor housing and wheel. All the rest of your turbo remains stock.
TonyG
11-23-2003, 02:00 PM
#3
Former Vendor
OK,now's the question:
Why 27/6 instead of 26/8? ( If you want to upgrade your 26/6 with KKK parts.)
...and one for the road: Is 27/8 way too big?
Had to ask this because my KKK-specs thread does not give enough data to make my own conclusions...
Why 27/6 instead of 26/8? ( If you want to upgrade your 26/6 with KKK parts.)
...and one for the road: Is 27/8 way too big?
Had to ask this because my KKK-specs thread does not give enough data to make my own conclusions...
11-23-2003, 02:39 PM
#5
Rennlist Junkie Forever
pete95zhn:
>>>Why 27/6 instead of 26/8? ( If you want to upgrade your 26/6 with KKK parts.)<<<
Because the K27 compressor flows a lot more air than the K26 compressor. The K26 compressor is why your boost falls off at higher rpms (the turbo can't keep up with the air demands of the engine at high rpms).
>>>Is 27/8 way too big?>>>
What is way too big? What's too much lag for you is acceptable for the next guy.
But I will tell you this:
The K27/6 will make its peak TQ at about 3500 rpms.
The K27/8 will make its peak TQ at about 4100 rpms.
The K26/8 will make its peak TQ at about 4100 rpms.
>>>Why 27/6 instead of 26/8? ( If you want to upgrade your 26/6 with KKK parts.)<<<
Because the K27 compressor flows a lot more air than the K26 compressor. The K26 compressor is why your boost falls off at higher rpms (the turbo can't keep up with the air demands of the engine at high rpms).
>>>Is 27/8 way too big?>>>
What is way too big? What's too much lag for you is acceptable for the next guy.
But I will tell you this:
The K27/6 will make its peak TQ at about 3500 rpms.
The K27/8 will make its peak TQ at about 4100 rpms.
The K26/8 will make its peak TQ at about 4100 rpms.
11-23-2003, 03:04 PM
#7
Race Director
Thread Starter
Tony, so a little machining is done? Thats what the turbo shop was saying to machine out and fit a new plate and they found a wheel out of a kkk spec book that they thought would be good... so I should say to them.... I want a k27 7200 compressor wheel and cold side bolted onto my 6cm2 hotside. and thats it? I am a bit of a dumb ****e when it comes to turbo part names etc. I should get Corky's book eh?
Trending Topics
11-23-2003, 03:23 PM
#8
Former Vendor
Originally posted by TonyG
pete95zhn:
>>>Why 27/6 instead of 26/8? ( If you want to upgrade your 26/6 with KKK parts.)<<<
Because the K27 compressor flows a lot more air than the K26 compressor. The K26 compressor is why your boost falls off at higher rpms (the turbo can't keep up with the air demands of the engine at high rpms).
>>>Is 27/8 way too big?>>>
What is way too big? What's too much lag for you is acceptable for the next guy.
But I will tell you this:
The K27/6 will make its peak TQ at about 3500 rpms.
The K27/8 will make its peak TQ at about 4100 rpms.
The K26/8 will make its peak TQ at about 4100 rpms.
pete95zhn:
>>>Why 27/6 instead of 26/8? ( If you want to upgrade your 26/6 with KKK parts.)<<<
Because the K27 compressor flows a lot more air than the K26 compressor. The K26 compressor is why your boost falls off at higher rpms (the turbo can't keep up with the air demands of the engine at high rpms).
>>>Is 27/8 way too big?>>>
What is way too big? What's too much lag for you is acceptable for the next guy.
But I will tell you this:
The K27/6 will make its peak TQ at about 3500 rpms.
The K27/8 will make its peak TQ at about 4100 rpms.
The K26/8 will make its peak TQ at about 4100 rpms.
Why Porsche chose to put 26/8 to Cup cars etc instead of 27/6?
And what's almost the most important thing to me,how much slower 27/8 is to spool?
At racetrack I can't notice any relevant difference with 26/6 and 26/8 spooling (my friend's car, '90 951,basically same mods than in my car),although there's definitely more power at upper rpm.
And I've noticed that boost fall,at 5th gear it's pretty hard to push those last 15 mph.
11-23-2003, 03:34 PM
#9
Rennlist Junkie Forever
NZ951
I suggest you get (if you don't already have one) a K26/6 turbo, and send it to a place like Powerhaus, Majestic, TurboCity, Turbo-Performance, etc...
They are familiar with doing the conversion. I've never done it myself (ie take the turbos apart and bolt other parts up, balance, check the tolerances, etc..).
Like I said before.. this conversion is extremely common.
TonyG
I suggest you get (if you don't already have one) a K26/6 turbo, and send it to a place like Powerhaus, Majestic, TurboCity, Turbo-Performance, etc...
They are familiar with doing the conversion. I've never done it myself (ie take the turbos apart and bolt other parts up, balance, check the tolerances, etc..).
Like I said before.. this conversion is extremely common.
TonyG
11-23-2003, 03:43 PM
#10
Rennlist Junkie Forever
pete95zhn
>>>But doesn't that #6 hotside limit exhaust gas flow and create more backpressure and thus rise temps?<<<
Obviousl yes. But so so will a conversion from a Garrett .70 a/r to a .58 a/r turbine housing.
Tighter turbine a/r equals more back pressure, equals quicker turbo spoolup, all other things being equal.
>>>Why Porsche chose to put 26/8 to Cup cars etc instead of 27/6?<<<
That's a good question! I've asked myself that many times.
A K27/6 will always out perform a K26/8 (and by a large margin).
I suspect it was much easier to dump some back pressure via larger turbine housing cost wise, vs having to have KKK design a larger compressor that was designed to fit the K26 center section.
>>>And what's almost the most important thing to me,how much slower 27/8 is to spool? <<<
I already answered that.
>>>At racetrack I can't notice any relevant difference with 26/6 and 26/8 spooling (my friend's car, '90 951,basically same mods than in my car),although there's definitely more power at upper rpm.<<<
You are the first person I've ever heard that has tried both and doesn't notice a difference of when the turbo spools. It's quite evident to me both on and off the dyno.
>>And I've noticed that boost fall,at 5th gear it's pretty hard to push those last 15 mph.<<
The boost falls off in ever gear if you are making enough power to over tax the K26 compressor (above about 260-270HP). The more power you are making, the sooner, and the more rapid the boost will fall off (obviously because you reach the limits of the compressor faster).
TonyG
>>>But doesn't that #6 hotside limit exhaust gas flow and create more backpressure and thus rise temps?<<<
Obviousl yes. But so so will a conversion from a Garrett .70 a/r to a .58 a/r turbine housing.
Tighter turbine a/r equals more back pressure, equals quicker turbo spoolup, all other things being equal.
>>>Why Porsche chose to put 26/8 to Cup cars etc instead of 27/6?<<<
That's a good question! I've asked myself that many times.
A K27/6 will always out perform a K26/8 (and by a large margin).
I suspect it was much easier to dump some back pressure via larger turbine housing cost wise, vs having to have KKK design a larger compressor that was designed to fit the K26 center section.
>>>And what's almost the most important thing to me,how much slower 27/8 is to spool? <<<
I already answered that.
>>>At racetrack I can't notice any relevant difference with 26/6 and 26/8 spooling (my friend's car, '90 951,basically same mods than in my car),although there's definitely more power at upper rpm.<<<
You are the first person I've ever heard that has tried both and doesn't notice a difference of when the turbo spools. It's quite evident to me both on and off the dyno.
>>And I've noticed that boost fall,at 5th gear it's pretty hard to push those last 15 mph.<<
The boost falls off in ever gear if you are making enough power to over tax the K26 compressor (above about 260-270HP). The more power you are making, the sooner, and the more rapid the boost will fall off (obviously because you reach the limits of the compressor faster).
TonyG
11-23-2003, 04:12 PM
#11
Race Director
Thread Starter
I issue is I am in New Zealand and dont 1. want to pay to freight my turbo around the world and two, dont want to pay in USD. I have a quote for 700NZD to do it here. But they seemed a little happy go lucky with the specs they think I should have and talked about machining. Is it normal to machine parts out in the conversion process?
11-23-2003, 04:39 PM
#12
Former Vendor
>>>At racetrack I can't notice any relevant difference with 26/6 and 26/8 spooling (my friend's car, '90 951,basically same mods than in my car),although there's definitely more power at upper rpm.<<<
You are the first person I've ever heard that has tried both and doesn't notice a difference of when the turbo spools. It's quite evident to me both on and off the dyno.
>>And I've noticed that boost fall,at 5th gear it's pretty hard to push those last 15 mph.<<
The boost falls off in ever gear if you are making enough power to over tax the K26 compressor (above about 260-270HP). The more power you are making, the sooner, and the more rapid the boost will fall off (obviously because you reach the limits of the compressor faster).
Who said I've driven it,I've raced against it...I just can't catch him,we run equal until my boost starts to fall,then he makes more gap. Maybe I should make few fast laps with it to also feel it.
But,tq peak can be at higher rpm and the curves can be (almost) equal,that only means that the other one makes more tq.
One should see dyno sheets from the same engine with different turbos (tunrd,of course) for real comparison.
You are the first person I've ever heard that has tried both and doesn't notice a difference of when the turbo spools. It's quite evident to me both on and off the dyno.
>>And I've noticed that boost fall,at 5th gear it's pretty hard to push those last 15 mph.<<
The boost falls off in ever gear if you are making enough power to over tax the K26 compressor (above about 260-270HP). The more power you are making, the sooner, and the more rapid the boost will fall off (obviously because you reach the limits of the compressor faster).
Who said I've driven it,I've raced against it...I just can't catch him,we run equal until my boost starts to fall,then he makes more gap. Maybe I should make few fast laps with it to also feel it.
But,tq peak can be at higher rpm and the curves can be (almost) equal,that only means that the other one makes more tq.
One should see dyno sheets from the same engine with different turbos (tunrd,of course) for real comparison.
11-23-2003, 06:22 PM
#13
Rennlist Junkie Forever
pete95zhn
How do you know you both are running equal boosts (using the factory gauge doesn't tell you enough to compare for sure).
Also, one car could have a weaker wasteagate than the other. The factory wastegates are junk, and over time, get weaker and weaker and weaker...
I've dynoed both the turbos. The results are just what I posted.
Also, on a 100k+ mile short block, my '86 951 with a K27/6 and the following mods, made just under 350RWHP at 20psi. At 17-18 psi, it made about 335RWHP.
52lbs injectors, adjustable fuel pump, chips, ARC2, MAF, Bursch Test Pipe, Borla XR1 Muffler (entire exhast 2.5"), intercooler pipes.
TonyG
How do you know you both are running equal boosts (using the factory gauge doesn't tell you enough to compare for sure).
Also, one car could have a weaker wasteagate than the other. The factory wastegates are junk, and over time, get weaker and weaker and weaker...
I've dynoed both the turbos. The results are just what I posted.
Also, on a 100k+ mile short block, my '86 951 with a K27/6 and the following mods, made just under 350RWHP at 20psi. At 17-18 psi, it made about 335RWHP.
52lbs injectors, adjustable fuel pump, chips, ARC2, MAF, Bursch Test Pipe, Borla XR1 Muffler (entire exhast 2.5"), intercooler pipes.
TonyG
11-23-2003, 06:56 PM
#15
Rennlist Junkie Forever
NZ951
The intercooler pipes were 2.25". Also... I played around with making them out of PVC. You can get a very large radius out of the turbo, into the intercooler with PVC. You might want to play around with it.
I plan to make my next set of of PVC entirely.
And, I don't know what has to be machined to get the K27 compressor on the K26 center section.
TonyG
The intercooler pipes were 2.25". Also... I played around with making them out of PVC. You can get a very large radius out of the turbo, into the intercooler with PVC. You might want to play around with it.
I plan to make my next set of of PVC entirely.
And, I don't know what has to be machined to get the K27 compressor on the K26 center section.
TonyG