PorscheDoc

I have to believe that this is about where the the little k26/6 runs out of steam, or the wastegate wasn't doing it's job....or both I have a Tial sitting in my office that I can throw on to confirm this. Thoughts?

For those that followed my engine build thread. New engine rebuild, stock internals for the most part with some minor head work.

Engine has about 1500 miles on it since the rebuild

K26/6, 2.5" exhaust with no cat, stock shimmed wastegate, 3 bar FPR, custom chips, AC delete, Manual steering (only one pulley being turned, that being the alternator)

16psi but it bled off to 10psi at redline.

4th gear runs on my Mustang Dyno

Weight set at 3000lbs with driver (though on the dyno it really doesn't change the numbers much). Car is significantly lightened.

Temps: IIRC the dyno was reading about 82ish

AFR's are leaner than I like, though the last spike at the end is where I lifted off the throttle at the end of the run.

Summer project (got to spread things out, just bought a house): Not 100% sure yet, but will start with V and end with itesse. I am excited to test the first item on the list, which hopefully sh944 has coming already

Thoughts? Input?

Cliff Notes: Edit: So far the general consensus is that the wastegate is probably shot, hence the late peak torque.

toddk911

The k26/6 seems to hold about 12-13 on most runs so I would say only holding 10 is more a WG issue.

Seems like you boost comes on slow for the 26/6 as peak tq is at 5,000rpm???

Yea, pretty lean at 5,000 on up as your hitting close to 13:1.

Especially for that little turbo that likes to make more heat than hp.

George D

That K26 should have max tq by 3500 or so. This chart doesn't look right for that turbo.

George

PorscheDoc

Turbo starts spooling at 2800 rpm.

PorscheDoc

Now is that that because the turbo is running out of steam at the higher hp level or the wastegate? I can't believe a k26/6 has the ability to make much more.

George D

If it's spooling at 2800RPM there is something wrong with the dyno or you are leaking boost very badly. Like I said, you should see a much lower max tq number.

My old K27#6 hotside turbo dyno hit max tq at 3500rpm. The number was 340wheel tq. I have the same hotside as your turbo and the K26 spools faster than a K27#6.

George

PorscheDoc

Sorry, there is nothing wrong with the dyno. I love that response

I have baselines of a stock k26/6, and peak tq is around 4500, not 3500

PorscheDoc

It is definitely not a lot of power under the curve type of chipset, lol

George D

It was just a question about why your chart is like this. I can scan my old dyno from 1999 and show you that max tq came on at 3500.

G

PorscheDoc

I have to believe the torque is probably more of how the chips are tuned (I don't know whose they are unfortunetly)?

George D

Here is a chart showing a chipped only K26#6. I've never seen a K26 dyno showing max tq coming on as late as 4500rpm.

G

toddk911

The easiest way to tell if it is turbo running out of steam or wg bleeding is hp vs boost graph. If the boost is rolling off it is wg. If hp is rolling off it is the turbo.

A turbo that is running out of steam will still be holding X amount of boost, within reason, to redline but you will not make anymore hp; just heat. So if you show 13-15 psi to redline but stop making hp at 5,500, then your turbo is running/ran out of steam.

But, if you see boost rolling off, then you are more in the wg area bleeding.

toddk911

True, as the chips could have a lot of timing pulled out and that is killing your tq in that area as the a/f seems ok in the spool up area.

George D

Here is a K26#8 which comes on LATER than the #6 turbo.

G

PorscheDoc

Makes perfect sense!