Imo000

They are all the same engine, how do you figure the 86.5 is stronger?

Daniel Dudley

Very nice job. Are you running a stock 85 exhaust ?

Imo000

You are right, 85hp from only 4.5psi is VERY, VERY good.

AO

I'm sure the answer has to do with something like "11" is 1 more loud than "10."

JKelly

+10

Since "85 crank hp" is a rough guesstimate, depending on whether a 15%, 18%, or 20% correction is used, can we just stick to the rwhp measurement like everyone else?

For instance, very few (if any) Rennlisters who have modified and dyno'ed their car use crank hp numbers in their signature line. When speaking about modifications and dyno results of those modifications, very few (if any) use crank hp numbers.

317 - 249 = a 68rwhp gain

This system appears to make 68rwhp at 4.5psi of boost on an 85 auto for $4,895.

Personally, I had hoped to see higher gains for that much money. Maybe put a little more testing into it and find out if there is a higher "safe" boost level for this kit.

Jim bailey - 928 International

I rather like the conservative approach of doing ONE THING at a time. What do you get with the blower ONLY . Obviously there is more opportunity if the exhaust is reworked Porken is a prime example of that. Too many cars get a laundry list of changes and it is impossible to know what did what. Just more options for the 928 owners.

Mike Frye

How many people are going to use a completely stock setup when they add an SC? I think Carl is trying to show what the BASELINE is here, not what it can do.

Anybody that get's an SC is going to have at least:
crossover pipes
possibly dual exhaust
aftermarket chips/sharktuned chips

I think Carl wanted to show just this part, then he can add the other variables to show what can be done.

If he had reported it on a car with these mods, the questions would have been: "Yeah, but what part of the gains were from the SC and what parts were from the other mods".


EDIT: Crap! JB beat me to it.

JKelly

Agreed. That's why I was hinting at the possibility of a little more "safe" boost.

Imo000

Yup, I agree too. That’s almost what I did when the SC went on. The car had a chip set ( was too lazy to pull it) in there but other that that everything was stock including weight (spare tire, tools, everything) and tire size too. The flowing winter I replace the cats with a used H-pipe and it felt like I picked up a few HPs there (probably around 20 or so) but don’t have any data (not even ¼ mile numbers) to prove it. Also, not that if you replace a bunch of things that you don’t know what did what BUT if something is not performing right, you don’t know what is causing it.

Rick Carter

And I always want someone else to be the canary in the mine.

JKelly

...but you already are the canary . You, Imo000, whall, and Tampa928, who is currently testing out the 85/86 murf kit.

How much boost are you running Rick? non-ic I assume.

Tampa 928s

86: x-pipe, chips and tuned up!

Rick Carter

I'm running about 5.5 with IC now. It needs a shark tune.

Carl Fausett

Back when this SC stuff all started some 4+ years ago, it seemed like all the posts were engine HP numbers. Somewhere along the way, some on the Forum have switched to prefer RWHP numbers instead. That's fine, I supply both so you can choose.

Porsche only published crank HP numbers, so I like to compare to that to get a before-and-after, but again, I provide both wheel and crank so you can use what pleases you.

This kit came in very, very well if you consider results from other comparable SC kits.
Our Stage 1 SC kit on the 16v K-Jet yields 80 HP from 6 psi, or 13.3 HP per PSI
Our Stage 1 SC kit on the 16v L-Jet yields 104 HP from 6 psi, or 17.3 HP per PSI
Our Stage 1 SC kit on the 16v LH-Jet yields 80 HP from 5 psi, or 16 HP per PSI
This Stage 1 SC kit on a 32v LH-Jet yielded 85 HP from 4.5 psi, or 18.8 HP per PSI

Thats the most improvement per pound of boost of any of these non-intercooled kits. All those numbers are stock injectors, stock exhaust too.

I think the improvement is because:
1) the marvelous 85/86 pipe-organ manifold breaths exceptionally well
2) the 4v heads breath better than the 2v heads
3) the Raptor produces a cooler (denser) air charge than even the Powerdyne I used in the other kits.

The transmission really seems to like this setup, too. It shifts better now than it did before! Many of you know that centrifugal superchargers come in at an exponential, not linear rate.

Although we are already producing boost at 3,000 rpm, the Raptor really "hits" at 4500 RPM and that makes for a fantastic upshift from 2nd to 3rd. Its a lot of fun and really has changed my thinking about 928 automatics. Ryan was also surprised and impressed - he said he'd buy an automatic now if it behaved like this! Very fun to drive. Docile when you wanna be, cranking when you wanna play.

Carl Fausett

I forgot to mention: we tested our cold air intake design while we were on the dyno.
We did a pull with the air filter assembly installed and also removed, there were no changes.