924Board.org

emoore924 · Joined: 13 Apr 2004 Posts: 2822

My local PCA region sponsored a Dyno day at XoticMotorsports in Cochranville, PA today. It was a charity event where the proceeds benefitted toys-for-tots.

They have a magnificent facility with an inertial dyno and lots of ECU flash software capabilities. Chris, Josh and Art were patient and knowledgable hosts. I highly recommend a visit if you have the opportunity.

Anyway, I thought I would share the results of my pulls.

Look here for the dyno graph and pics of the car on the dyno.

http://www.ofoto.com/I.jsp?c=dkve97l.351qw3tl&x=0&y=-gh8ii6

The car is a 1980 924 turbo with adjustable boost, intercooler, some headwork, microfueler etc. Running a 50/50 mix of 94 and 100 octane fuel. The car has not been tuned at all. This is truly a "baseline" result.

Pull 1-4: Blew an intercooler hose off early in pull #1. As a result boost and HP were way down -- only pulling 2lb boost and 100hp. Obviously something was wrong but I did not find the problem until after pull #4 when the car was already unstrapped. The results of pulls 1-4 are therefore not included here.

Pull 5-7: I went off and fixed the hose, came back and did 3 more pulls. #6 and #7 were virtually identical so only #7 was included in the graph. Pull #5 was at "stock" boost of 7lb. For pulls #6 and 7 the boost was turned up to 12lb. There were no other changes.

With only the boost change, HP went from 132 to 150, tourque went from 149 to 172. These are at-the-wheels numbers of course so add back roughly 10-15% in frictional loss to determine flywheel results.

I intend to continue to make improvements and changes so stay tuned.

If you can't get to the pics, please LMK

Peter_in_AU · Joined: 29 Jul 2001 Posts: 2745 Location: Sydney, Australia

the car looks great in the martini colours.
_________________
1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)

Learn to love your multimeter and may the search be with you

My924gtc · Joined: 14 Aug 2004 Posts: 1362 Location: 248

Ditto that.

Where did you get your stripe kit?

Looks great.
_________________
MJ
'81 924 2.0L T
'82 924 2.3L SC/EFI <---online fall '06

Sponsor of the 944 Cup and Super Cup
Sponsor of the "2006 Battle in the Badlands"

924guy · Posted: Sun Nov 14, 2004 10:59 pm Post subject:

some very respectable numbers there, and i agree with the above, Car looks awesome! lets see some more pics

_________________
Eric
78 924
82 931 SE "smokey"
99' VehiCross
Y2K Honda Insight
http://www.cardomain.com/id/924Guy
Performance by Pasha

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA

Hey Ed:

What's goin on? With the boost cranked up and over about 5300 rpm hp and tq fall below the values seen with stock boost.??

Also, see how extremely flat the hp and tq curves are at stock boost. Interesting.

JB
_________________
John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82

emoore924 · Joined: 13 Apr 2004 Posts: 2822

Hey all, thanks for the comments.

The stripe kit is Porsche factory original, put on the car by Holbert Racing when the car was built in the late 80's. It is still in pretty good shape. You can see the car in their 1988 racing catalog here:

http://members.rennlist.com/944sandmore/HRP944SW.jpg

John, it is kind of hard to see but the hp curves are roughly parallel to one another as are the trq curves. There is no crossover. So, the flat curves are HP from each of the runs, the two with the humps are trq. So, ax the board, the higher boost results in both higher trq and higher hp. The blue lines go together and the red lines go together.

I will try to post some more pictures of this car tomorrow. I will update this thread when I do so you can take a look.

emoore924 · Joined: 13 Apr 2004 Posts: 2822

I added a few "vanity" shots of 924zilla from various car shows this summer. You can access them via the link to ofoto I posted above. They should give you a reasonably good idea of how the car looks with the martini stripe.

However, I have to say that it is a bit difficult to get the full impact of the superwide fenders (+2" wider than a 944) without seeing the car in person. If it is any indication, the BBS wheels in the pics are 9 and 11" wide. The closeup is of one of the rears that I refinished. It has a 285/40/15 tire mounted and I still had to use about 1" of spacers to get it to look right. It is a w-i-d-e car.

Enjoy!

My924gtc · Joined: 14 Aug 2004 Posts: 1362 Location: 248

Nice!
_________________
MJ
'81 924 2.0L T
'82 924 2.3L SC/EFI <---online fall '06

Sponsor of the 944 Cup and Super Cup
Sponsor of the "2006 Battle in the Badlands"

81turbo · Joined: 03 Nov 2002 Posts: 1065 Location: Oakland, CA

So if we add back 20% for frictional loss you are only getting 180hp at 12psi. Is anyone else wondering what the hell is wrong with this? With an intercooler and that amount of boost you should really be getting better numbers than that. After all the euro spec car with less boost made about that much power without an intercooler or headwork.

-nick · Joined: 16 Nov 2002 Posts: 2699 Location: Cambridge, MA

Yeah, I'm a little surprised at this too. Not only do the numbers seem a little low across the board, but I would have expected that you would see more than ~5hp per 1 psi. Were you able to get an A/F reading from the dyno too? And where is your timing set at?

The car looks mean though! A real '70's road racer.

nick

emoore924 · Joined: 13 Apr 2004 Posts: 2822

Khal · Posted: Fri Nov 19, 2004 9:25 pm Post subject:

Check this one for comparison. Far as I know, a stocker Euro-spec '81...
_________________
'80 924 Turbo

emoore924 · Joined: 13 Apr 2004 Posts: 2822

Ok, here's the first feedback regarding this plot. I talked to a p-car master mechanic bud of mine about the graph and his thoughts run along something like this...

There is some kind of restriction or bottleneck in the system. This is evidenced by the fact that the HP hits a ceiling at 4500 rpm and stays right about 150 pretty much all the way to redline. That should not be.

The plan from here is as follows...

Get the car set up right with regards to timing, fuel mixture, etc. Then do another pull with the changes to see if there is any difference. This is not to check the impact of the changes but moreso to re-baseline the car.

Then, we're going to go through the car looking for things that might limit throughput. Specifically, the intake system up to the intake port (in particular the intercooler and all its plumbing) and then from the exhaust port on. For now, we're going to leave the head as-is.

We believe that if we find the place where the system is constrained, we will be able to significantly improve on these numbers in fairly short order. Conversely, if we don't remove the constriction, it is believed that any other things we do will have little or no impact.

Thanks for the other dyno plot. Anyone else have one? I really like working with facts...

Stay tuned and thanks for the input.

81turbo · Joined: 03 Nov 2002 Posts: 1065 Location: Oakland, CA

What type of intercooler are you running? Any pics.