Is the k26/8 the best compromise between lag and power for a 944 S for street/ DE?
#61
What's just as important as the turbo itself, is engineering the whole system properly. It's better to have a slightly smaller turbo, but have it work as efficiently as possible so it makes the most use of its size:
You need a MAF and a big enough air filter (so that the compressor can "grab" its' air without a pressure drop).
The air filter should be at a location where it can grab cool ambient air (preferably at a high pressure zone on the car). Turbos are most efficient when the inlet air is as cold as possible and the hotside sees as much heat as possible.
Intercooler should be clean and free of oil.
There should be no vacuum/pressure leaks.
Need a 3 inch exhaust with no cat and the wastegate has its' own dedicated exhaust. Custom headers are a big plus.
bebbetufs;
if you do this with a k26/8 and you will have achieved what you asked for in your original post. Best combination of power and spool; the car will come alive. These mods also help to push detonation further out of the picture, so you can even lean up the air/fuel mixture a bit to bring it a little more into the sweet spot (this might be a little unpopular with most vendors/tuners, lol)
You need a MAF and a big enough air filter (so that the compressor can "grab" its' air without a pressure drop).
The air filter should be at a location where it can grab cool ambient air (preferably at a high pressure zone on the car). Turbos are most efficient when the inlet air is as cold as possible and the hotside sees as much heat as possible.
Intercooler should be clean and free of oil.
There should be no vacuum/pressure leaks.
Need a 3 inch exhaust with no cat and the wastegate has its' own dedicated exhaust. Custom headers are a big plus.
bebbetufs;
if you do this with a k26/8 and you will have achieved what you asked for in your original post. Best combination of power and spool; the car will come alive. These mods also help to push detonation further out of the picture, so you can even lean up the air/fuel mixture a bit to bring it a little more into the sweet spot (this might be a little unpopular with most vendors/tuners, lol)
#62
The 7006 and 7200 wheels are very close in size. Approximately .080" different in diameter. When Porsche came out with the 7200 series turbo for the 911 - they changed the hot side and it spooled much quicker. The cold side is very close. Charlie at evergreen can give you the exact specs, but the hot side will affect spool up more than choice between the 7006 and 7200 series compressor wheels.
#63
Custom headers are a big plus.
Would you rather spend the money on the headers than a modern turbo?
Would not the k26/8 run out of omph too early to take full advantage of these mods?
#65
these mods will help to get the most out of the k26/8 and part of that is not running out of omph as early as suspected.
If, however, 320 crank hp and full boost at 3,000 RPM is not a good enough compromise for you, then, I guess money would be better spent on a turbo.
I got headers from SFR and it made more of a positive difference than I expected (I was skeptical).
#66
If, however, 320 crank hp and full boost at 3,000 RPM is not a good enough compromise for you, then, I guess money would be better spent on a turbo
Very interesting comment about the headers. Did you keep the stock x-tube? Did they affect torque or low rpm driveability?
#67
I need to get someone to sit in my passenger seat and watch the boost on the EBC display - I can't safely see it when I am driving - then I can tell you if/when the 26/8 runs out of puff. My dash boost guage is pegged at 2 bar from ~3000rpm onwards, so its not a great indication. If I had to guess, I would say that the way it feels pretty much matchs the way the LR graphs look - so peak tq by 4000rpm and then reducing after that. Of course the hp is still building as revs build so the acceleration is still strong. The point where it feels natural to change up is not much more than 6000rpm and my butt dyno tells me that circa 275RWHP/300lbft is closer to the truth than 300RWHP/345lbft at the 14.5psi I am running - even though I am running the 300RWHP kit. A dyno appointment beckons before next summers driving season.
#68
With a stock head ,headers, cam etc I can't imagine needing a smaller turbo than the Gt3076 7 blade .63 that I had on the car at one stage. It felt 'very' responsive and perhaps just a little bit linear compared to the previous turbo that I had on the car which was a stage V Vitesse turbo. (That turbo was designed for a modified 3L motor yet was still driveable on a stock engine). My personal guess is that a GT28 would be too small. Thingo ran a GT3071 for a while and it felt similar to the abovementioned 76 but he had a large hotside from recollection.
A 28 would be awesome around the city or for Auto X but I'm not sure that overall it would be the best size for our cars. imho.
A 28 would be awesome around the city or for Auto X but I'm not sure that overall it would be the best size for our cars. imho.
#72
The GTX is billet (advertised). Traditional impellers are cast in a flexible mold (fact). The rest is going off of memory from when I was looking into it. The billet is stronger, so the blades flex less. That enables smaller impellers to flow larger amounts of air more efficiently. Smaller impellers have lower inertia, which ceteris paribus, spool more quickly (that's also a fact).
#73
GREAT NEWS
I just received a phone call from the people who supplied my turbo. They admitted to having made errors in assembly which caused the nut to spin off. I have to say I was wrong in my assumptions about this company and that they seem like a much more respecatble company than I first thought.
Next step is to see if they will cover some of my work and one-time-use materials like gaskets, lock nuts etc, but this is secondary to replacing the turbo.
Now all I have to do is to decide if I sell it and go for an upgrade or stick it back on.
Next step is to see if they will cover some of my work and one-time-use materials like gaskets, lock nuts etc, but this is secondary to replacing the turbo.
Now all I have to do is to decide if I sell it and go for an upgrade or stick it back on.
Last edited by bebbetufs; 11-21-2011 at 06:59 AM. Reason: TYPO
#75
I can only speak for my car:
Ported and polished head and throttle body
Raceware studs
Widefire head gasket
K26/8
Matched flow 55# injectors
3 bar FPR
LR Cam
LR 3" racing exhaust
LR Manual Boost Controller
Shimmed waste gate
A tune
Holds 19PSI quite well
A very reliable build for Street/DE....I'm happy.....
Ported and polished head and throttle body
Raceware studs
Widefire head gasket
K26/8
Matched flow 55# injectors
3 bar FPR
LR Cam
LR 3" racing exhaust
LR Manual Boost Controller
Shimmed waste gate
A tune
Holds 19PSI quite well
A very reliable build for Street/DE....I'm happy.....
Last edited by White_951; 11-21-2011 at 04:40 PM.