blade7

I've read pages and pages here but still dont know if a K27/8 is big enough for a road going 8v 3.0 or how much boost it will run safely. I'd like a fairly easy bolt on and I'd rather not spend $1k + on a turbo but I guess it's pointless to build a 3.0 and then choke it with too small a turbo, does a K27/8 work ?.

Paulyy

A few people used that turbo.
for example on the 3L registry
3. John Torgersen, 3.0,Steel, 104, 88, JE, 2.7, Motec M4 Pro,K27/8, 383HP@15

I've looked at 3L for a street car and i don't see it necessary really.
with the money you spend on the 3L you could make a strong 2.5L

blade7

I've read for and against re the K27/8 and I understand what you mean about 2.5 v 3.0 but I have a spare 2.7 engine and an S2 crank and as I'm getting lazy in my middle age I want the grunt .

Paulyy

Makes sense

I personally would just just a GT/X series turbo as i don't like the KKK series turbos.

DanaT

WTF do you find spare 2.7l engines sitting around?

blade7

Well 2 years waiting for a decent one to turn up that wasn't hundreds of miles away or silly money for a start , pulled it apart and no corrosion around the waterways or scores on the bores, good waterpump and out of an auto. Picked up an S2 crank that looks unmarked and bought an engine stand, running out of reasons not to go 3.0 now, though it's too cold in the garage to do anymore for a few months.

74goldtarga

My guess is that it would be a little small on the hot side. I have heard that it drops off in terms of efficiency over 18psi but have not had the chance to verify this with my turbo. I am happy with my 27/8 for my 2.5 but am wondering if I shouldn't have gotten a turbo with a bigger hot side. With a 3.0 this would become a bigger issue, however, you would probably get good street performance. I am still learning, but my .02$

Paulyy

they are used on 3L 930's so im sure it'll be good on a 3L 944

dand86951

The K27/8 combo will work fine for a street car assuming you don't want to run the boost up past 1.2 bar. The #8 hotside will get you into good boost around the 3000rpm mark and even with partial throttle it will give you much more torque at the lower rpms. I ran a K29/8 in my 3.0 and for the street it was great. Even on the track it worked very nicely as I kept the boost down to 14 psi for running on pump gas and never had any issues. So if you have it, don't be afraid to use it. There are other turbos that are probably better but the K27/8 should be bullet proof.

blade7

Without ever being in a 3.0 at 1.2 bar I cant say if that would be enough but I was planning on a bit more boost for the work and expense.

Paulyy

Do you have a power goal?
Any goals for the motor?

TurboTommy

It's pretty easy figuring, really.
The k27/8 is good for 350 crank hp, reasonably. So, that's what you're gonna get without asking too much from the turbo, regardless if it's 2.5 or 3.0.
With the 3.0L it's just going to be a nice wide grunty powerband. Also, that would be less than 1.0 bar boost with the 3.0L Unless you have an EBC and you can dial in more boost in the mid-range and then let it tapper off.

blade7

Judging by the 400+ bhp 2.5 I drove I'd like the top end of that combined with something positive happening from around 2.5k .

dand86951

1.2 bar is 18psi. Without a lot of details at 18psi a 3.0 litre is very very quick. If you want a over 400HP street engine on pump gas then it gets a bit more complex. If you are going to run E85 then even a K27/8 will let you run 20psi for street use, just don't run it on the track for 30 minute sessions without a whole lot more intercooling.
I just know that at 1bar my 3.0 was very quick and at 1.2 bar it clocked a 121mph quarter mile. If your goals are higher then I would go to a newer Ball Bearing turbo right off the bat.

blade7

I wasn't converting bar to psi accurately, 18psi is pretty much what I am aiming for on the best pump gas, unlikely to be any track days and I'd be careful on really hot days.