MitchB

Good reading - the timing couldn't be better for me...
I still have some questions though - I'm pulling my turbo this weekend for a rebuild and just abt made up my mind to bite the bullet and upgrade to a K27 variant vs. stock rebuild ($690.00 vs. $330.00).
How different in spool up and HP potential is the K27-6 from the K27-8?
280+ HP with a stock AFM sounds great but too much lag with zero low end isn't worth it.
If someone has a different "bolt in" Turbo for the same price I'd love to hear abt it before I spend my shrinking money supply.
thx

hosrom_951

Porschhhh951: No, im not taking it in a bad way. I guess i was mistaken here, and NO i didn't get the running on 18+psi needs race gas from what i read, it was what i was told by SEVERAL vendors i contacted.

I myself wasn't sure on that subject either, since many are hitting 20+psi on 93 octane in hot weather with no problems.

Just exactly HOW hot is it in Texas? it's scorching here......well, now it's settling for the 100F range during the day and around 85F at night (used to be well over 120F during the day during July~August).

UK952

I have a K27/8 but only had a K26/8 to compare it with, It spools a little slower, a bit like the 26 was before I had a boost enhancer. When it hits it hits harder and up to the red line, my 26/8 was sick and the extra on a rebuild to K27 wasnt much more - a lot less than a new garrett or whatever, I would of regretted later not doing it while it was out. Dont forget the extras though, adaptor for the coolant hose, adaptor for the J Boot, K27 chips though I ran standard boost on the standard chips or a while with no problems - just a load of spare potential.
Tony

UK952

Oh yes I have stock intake with KandN panel standard injectors, ESS exhaust and cat bypass, reliaboost, guru 15psi chips and 3bar FPR.
My car makes just under 300rwhp, New injectors, 18psi, EBC and MAF/MAP will free up a whole load more, but I need a new clutch and considering a gearbox rebuild while I'm at it, so they are on hold for now.

Tony

PS passed a 360 and a GT3 on my last trackday

Duke

I must say that with a MAP-kit installed and good midrange A/F-values (not too rich) turbo lag or off boost power has never bothered me. Getting rid of the of the AFM made wonders, even when the car isn't on boost!

The car now has plenty of power at all rpm's and is a blast to drive even in the city.

Or perhaps it's just my mind telling me I'm ready to step up to a considerable larger turbo

MitchB

UK952 -
That's exactly the info I needed.
My budget won't allow everything I would like to do right now. But, since I have everything apart right now to replace the exhaust manifold(s)... I'm hoping to do just the head gasket, WG (GURU), turbo, chips (hopefully 18 psi) with a EBC for now. If I can wait on a MAF/MAP, injectors, piggy back etc. for now, that would be great.
I was just afraid a K27/8 with the AFM might cause some driveability issues... I can live with stock turbo spool up characteristics. Has anyone gone for a/the quick spool 27/8?

schnellfahrer

Gustaf, I just spoke to a fellow who tells me his 27/8 doesn't boost until 3000 at all. He is running stock afm. Will the turbo spool quicker with a MAP or MAF?
Which MAP kit / chips do you use and do you have any issues with it?

schnellfahrer

There is a quick-spool 27/8??

UK952

Glad I could help.

MAF or MAP should help with the spool as its easier or the air to get in (but no experience yet )

Just thought though I had a k26/8 which then had a K27 Coldside added and the whole lot rebuilt, does that make it a K27/8 or a K27 K26/8 hybrid?
Not sure of exact spec but I beleive I have 360 bearing and some work on the internals but not much.

My dyno plot is here
http://www.titanic.co.uk/cgi-bin/gal...9&intReqGall=2
showing flywheel figures, there was a standard boxter S made 252bhp the same day so we think they are pretty accurate.


I forgot to add I also have a tial,

but upgrade path was turbo and Boost enhancer standard chips about 6 months + exhaust or a bit

Then, Guru (FPR, reliaboost, chips, shims) about 3 months

Then after that Tial (single port mode) and vacuum lines about 6 months ago.

EBC soon and 18psi chips

then injectors

Tony

Duke

No problems at all with a K27/8 and AFM. I drove with that config for 2 years with 3 different chips and never had drivability problems.

Duke

Sounds about right, there isn't any boost worth talking about below 3000 rpm. But do you really consider that as a problem? Don't you guys never shiftdown To me a shiftdown with dubbel clutching adds so much more fun to it

The turbo spools faster with MAP/MAF but it also pulls better below 3000rpm now.

An important note is that I'm still using stock wastegate though!

Half my package is built on the Guru MAP-kit. I don't consider it having issues, even though it can be a bit grumpy during cold starts. But I don't have a temp sensor right now so I cannot blame the kit.

MitchB

My concern with lag stems from my 930. It has a aftermarket turbo ( a "quick spool") but still has some lag. Most of the time it's not an issue, but sometimes it's just a PITA. I attribute most of it to very old fashioned FI that the 951 doesn't have. I can live with it in one car, but don't want it in both.
It's been well documented that a large part of the benefit of a MAP/MAF conversion is much improved throttle response i.e., off idle oomph. Perhaps this is why the MAP users don't have any lag complaints and the AFM users might...?

Danno

Duke, you didn't get a temp-sensor with your MAP kit? I'll send you another one.

As to the low-end response from a K27, it has a lot to do with the programming in the chips. From previous threads, my secret's out on how I get rid of a significant amount of lag in the chip-kits; by programming in the opposite direction as most aftermarket chips. John Kaufmann (Jake951) has done some pretty good research in this area with his MAP kit and has actual numbers to go with various low-end air-fuel ratios. It's even more so with a K27 because of the extra lag compared to the stock turbo, so to map a K27 optimally, you must remove fuel in the low-end and add fuel in the high-end compared to a K26.

Now the differences between a K27/6 and K27/8 is similar to that between a K26/6 and K26/8; about 750rpm. So looking at Farzaan's Dyno Day, you can look at the first set of comparisons between the '87 951 and '89 951 (both on APE chips. Here's the chart:


You can see that the K26/6 has more low-end flow, but falls off more in the high-end than the K26/8. You can expect the same differences in the K27, but not as great if you have the fuel& ignition programmed optimally.

shortyboy

bump,still looking.............its been a week since danno emailed back about my chips.maybe hes busy,iono.so im on the look out for k27 chips for a 1987 944 turbo.thanx