nize

hi guys, i recently got the new car dyno'd and was seeking some advice. first the list of mods;

-weltmeister chip
-shimmed wastegate
-3bar fpr
-LBE
-lindsey 3" exhaust (edelbrock rpm muffler, no cat)

as far as i know, everything else is stock, including the k26/8 turbo-s turbocharger.

the questions;
1) does the torque seem to drop off awfully fast?
2) should the HP be climbing all the way to 6k rpm instead of dropping off?
3) on full open throttle, the car emits visible greyish smoke out the exhaust. it's not burning/leaking coolant. it is burning oil but not any more than any other 951 i've ever owned or seen. would a failing/leaking turbo cause this?
4) with 345torque, shouldn't it be making more than 270whp ?

here are the graphs, thanks guys.

hp/torque;


a/f;

black944 turbo

That is some nice power and the a/fs look pretty good as well. Black smoke from the exhaust is due to being rich under boost. It is normal. The others I can't answer due to owning a 26/6 car.

streckfu's

What's your boost doing? If it's bleeding off badly, your WG may be shot even with the shims.

Waterguy

Check your boost curve and control. The only way I know of to make 345 ft-lbs of torque at the rear wheels with a K26 turbo is to turn the boost up very high. Like not connecting the boost control line to the wastegate, or clamping it. It looks like you have uncontrolled boost which is making a constant 270 rwhp from 4200 rpm to 6000 rpm. The falling boost is probably the flow limit of the K26 compressor.

aeronautica86

thats a LOT of torque for a a stock 26/8! the Hp looks to be on par with other chipped k26/8s but I would have expected the tq to be closer to 300-310 range at the wheels. the hp curve looks pretty standard for a k26/8, and the tq dropoff is usual as well, though it does seem that yours drops quite a bit (more akin to the tq drop on a 26/6), but this could be due to the wastegate

what gear was this run done in?

nize

boost is spiking to 21psi (i believe this is normal), and then dropping and settling at around 16psi. is there a way to test the wastegate relatively easily? it does sound like perhaps the wastegate is bleeding boost too quickly, as compared to my original 88 car which didn't even have shims.

nize

the boost control line to wastegate is connected and operates properly (i checked this when i was replacing the cycle valve).

if you look closely at the hp curve, it actually starts to drop before 6k, which i thought was strange (it resembles a k26/6 turbo graph). i thought the k26/8 turbo was supposed to gain hp right up to 6k, is that not correct?

does anyone else have a stock turbo-s graph?

streckfu's

21psi is NOT normal and explains your TQ. Do you have the fuel to support that? How many threads are showing on the LBE and how are you not hitting overboost protection (removed by the chips)?

nize

4th gear as per standard procedure.

nize

if you look at my a/f graph, doesn't it seem like there's more than enough fuel to support it?

the LBE is stock as received by lindsey, i did NOT adjust it either way nor did i ever tinker with it. this is in fact the very same LBE that used to be on my 88 car so i'm assuming it's set at the pre-set 12psi or 15psi(?) as shipped by lindsey.

i would think that the chips remove the overboost protection? i'm still using the stock cycle valve and it's been recently tested and replaced so i know it works fine.

nize

btw as a sidenote, i've read that the 951 is designed by the porsche factory to initially OVERBOOST at first in order to get the turbo spooled quickly, and then quickly settle at the set boost level. i've actually confirmed this on five other cars with aftermarket boost gauges. initial throttle boost spikes for a second and then settles a bit lower, which is why i was thinking the initial 21psi spike was normal.

is something else going on here?

streckfu's

You're right.

I'm at a loss. Do you have a boost gauge installed or was this based on the dyno?

With the LBE at it's normal setting and the CV in place, I'm not sure how you can make 21psi without something failing. But then your AFR stays smooth. Almost too smooth. Are you certain about their accuracy?

nize

i have a VDO aftermarket boost gauge installed and it is calibrated correctly.

special tool

If you put a real wastegate in this car, you will burn the headgasket first or second pull at that boost.
Remember what I told you.

pk951

As far as i know when you install any kind of LBE in line with CV you will get spikes like you have.

How do you know you are boosting to 21-psi with stock gauge?

That AFR is very good for WELT chips. With CV boost should be no more than 13-psi, then by redline down to 9-psi or so.