Thanks King for making things so clear.

John, you are right, I did want a turbo with a #8 turbine back then. While the final reason I did not buy one of your stealths was financial I will admit that it goes against every grain in my body downgrading from the once coveted #8 to the "lesser" #6. Stupid I know, but this thread is helping Would not a Stealth #8 give more power AND slightly better spool? I'm not worried about the lag I have now, so that would be my benchmark lag-wise.

I realize it is a tall order but is it possible for you forum experts to give some estimates as to how much power vs spool these options can be expected to give with 3bar FPR and stock injectors?

stock k26/8
upgraded k26/6
upgraded k26/8
k27/big six
super 38
super 48

 

Given this conversation has come full circle back to k26/6 and k26/8 turbos, I was wondering if the numbers on Lindsey's 270RWHP and 300RWHP kits are accurate in people's experience? My car is running the Lindsey 300RWHP kit with 26/8, Profec BSpec, 55# injectors and a bigger intercooler but only 14.5psi of boost vs the 20psi of boost in the graphs on the LR site. The expected lag is present but by 3000rpm its happily boosting away and seems to make a sensible amount of power for UK roads. Sounds like A tune or M tune would both help with the lag, but I am actually pretty happy with the way the car goes now.

So I guess I am going full circle as well and asking, how far can you go with the std k26/8?

Apologies if this is a slight hijack (having now seen the OP's last post)

 

Not to worry. I think your question is very appropriate for this thread.

 

When you look at those number they very rarely hold those numbers til redline with the K26/8. You will achieve them in the midrange, but the K26 is just out or its efficiency range by then. Someone else could explain better, while you can get those numbers they don't hold them to redline.

 

When I took my first 951 for a test drive...well it was about 1000 miles and I loved it. It was 95% stock. Super comfortable highway cruiser. Then the mod bug bit like most of us. On the other hand, I've been in a 2.5L with many of the mods you've currently got and thought it was fantastic. Seemed to cruise fine in my estimation. While it's nice to reminisce, I think a stage 3 setup is well within a reasonable modification without losing sight of the Original car.

 

Yes indeed - the LR dyno chart clearly shows the tq curve peaks at about 3800rpm at 345lbft and by 5800 its done to 275lbft. They don't even seem to run the car past 6000rpm.



From the graph, the k26/8 is clearly making decent boost at 3000rpm, so the lag is managable - and that is exactly what mine feels like to drive. No doubt a turbo that can flow more air can hold that tq curve to higher rpms and make a lot more hp perhaps at the expense of lag.

 

Totally agree. My Silver Rose had suspension rebuilt as stock with new rubber bushings and engine rebuilt to ~300RWHP and its a joy to drive. Even with the wastegate dumping to atmosphere and 3" exhaust its super civilised for cruising (compared to even a std 911 of the same vintage). Its too soft for a dedicated track car (but I have a 911 track car for that). When I bought the car a couple of months back, I thought maybe I would modify it some more, but I think I really like it as is and maybe I have accidentally hit a kind of sweet spot - hopefully reliable and not too expensive to keep, certainly fast but very easy to use, comfortable enough to take the wife and kids at the weekend and still looks good enough that I feel proud of driving it. Really a great car.

Edit - woohoo, got my avatar to work as well!

 

Another question in this area--

How does the lag between a 26/8 and a 27/8 compare? I already have a 26/8 so I'm totally used to how it comes in--is it SIGNIFICANTLY worse with a 27 cold side?

 

I may have a core K26/8 in Atlanta that I could very easily pass on to John at Vitesse as he and the technician doing my rebuild are pretty close. I'd hate to see something that small be an obstacle...

PM for details.

 

IICR 100-200 rpm laggier

 

Upon reading over this thread, it seems you are after a stock turbo that spools better than a 'stock' turbo. Like 67king mentioned, you can take your stocker and turn it into the monster it 'can' become. That way, it will have better spool-up, and hopefully offer a little more on the top end as well, although I'm sure if something like say, a "stealth turbo" from vitesse would have a different efficiency range after being modified. All the while however, you'll be still be very civilized in power and thus fuel consumption, and, combined with a good MAF, have a a pretty killer setup IMO. Best of both worlds!

(OT) PS: Adonay, wow! 26psi...

 

That seems unnoticable...

I've found conflicting information as to whether the 7200 or the 7006 have different compressor housings...is there one to watch for, or are the differences in the exhaust side?

 

I think that they are almost the same wheel. I have spoken to a person like a year ago and I remember seeing the video. That turbo was very responsive. Also Cheetah turbo located in Portchester NY looked at the turbo and said that I could change the thrust bearing to a 360 bearing and it would with the spool up.

Here's the response I got from a Gentleman named marcesq which was runnin a 7006/6 combo. The video is not there anymore:

Re: K27 7006

--------------------------------------------------------------------------------

I had no complaints until it failed. My car, at the time was 2500lbs, chipped and had a 3" straight exhaust to the rear of the car. I was running 15lbs of boost and could stay with GT-3s powerwise. Here is a video of the car with the 7006: http://video.yahoo.com/watch/289576/2027276

Hope that helps.

 

Does anyone run a garret GT25R or a smaller GT\GTX turbo looks to me everybody is going GT30 or bigger and looking for power. Sure a true those bigger turbos spool fast but spool starts further down the rpm lane. I don't understand why there are no commonly used aftermarket turbos out there that can beat the old k26 in terms off spool and delivering equal or slightly improved power to stock.

(OT)
@Black51
Yes did run that before my oil pick up tube broke this fall. And will continue use the same boost profile after rebuilding the engine. Car feels great and is very responsive at high boost.

 

PM'd.

I second Adonay's question. Why is there so little information on the smaller BB and other modern turbos? Does everyone feel that there is no value for money in not going as big as possible when a new turbo is needed?

I cut this from a PM I just sent to 333pg333. This is my first attempt at ranking the "better than stock spool, but slightly more power" segment of turbos from best to very good based on impressions from this thread:

1. a gt28 based turbo, perhaps upgraded at a later stage with a gtx compressor when they become available in smaller sizes.
2. second is a tie between a Lindsey super BB
and a Vitesse stealth turbo
3. Modified k2/8 or a 27/"big six"

333pg333z