3.6 engine dyno pull, results for those interested Options

[nine14cats]

Here is the engine dyno pull for my 1995 3.6 993 pre-vario ram motor currently inside Fritz. SirAndy has the exact same motor configuration that I sold to him. (I had 2 3.6 engines for a few weeks!)

Motor has stock ECU, with the stock air filter and box cut to allow more air flow. 1 3/4 inch headers with Phase 9's. No AC or PS pump. 100 Octane gas.

It is interesting to note that this motor was $7500 delivered to my door 2 years ago with 34K miles on it. I sold the 993 exhaust, the upper assorted hoses and engine tin for $700. The headers were ~$550, so I came in at 7350.

The dyno was performed by Jerry Woods and the figures have been corrected for altitude and humidity and whatever else is corrected:

RPM HP TQ
--------- ---------- ----------
2500 87.1 182.9
3000 112.4 196.7
3500 137.7 206.6
4000 172.2 226.0
4500 208.6 243.4
5000 246.1 258.4
5500 264.3 252.3
6000 287.6 251.7
6500 282.6 228.2

Pretty awesome torque curve. And you can feel it. Right now I have a shift light set at 6K. I remember Brad saying the shift point for acceleration is about 500 RPM past peak Torque....which makes my shift point between 5500 and 6000 RPM. Factory red line for the motor is 6800 RPM I believe.

SirAndy,

This is a good basis for you to start with your chip mods and air intake mods. 300+HP with a chip seems attainable. The headers used for this dyno pull are the ones I sold you.

If we didn't have to use a 915 box, this -6 conversion swap makes alot of sense. 288HP out of a non-stressed motor with hydraulic valves.

Nice! (IMG:http://www.914world.com/bbs2/html/emoticons/beer.gif)

Bill P.

[SirAndy]

QUOTE (nine14cats @ Feb 7 2006, 06:00 PM)

SirAndy, This is a good basis for you to start with your chip mods and air intake mods. 300+HP with a chip seems attainable. The headers used for this dyno pull are the ones I sold you.

schweet! yes, excatly what i was looking for ...

thank you sir!
(IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif) Andy

[Dave_Darling]

QUOTE (nine14cats @ Feb 7 2006, 06:00 PM)

... I remember Brad saying the shift point for acceleration is about 500 RPM past peak Torque....

In theory, you want to shift where the power available to you in the new gear is equal to the power available in the old gear. So something like 500 RPM above peak power, not peak torque! If you shift before peak power, you will lose more acceleration by having to go through a taller gear than you gain by putting the motor close to its peak torque.

Remember, stock 914-4 makes peak torque at 3500 RPM. Why do we shift at 5000? Because that's peak power.

In a given gear, you accelerate the fastest when the engine is at its torque peak. But if you can choose a gear that runs the engine near its power peak, that will give you greater acceleration yet.

--DD

[DanT]

Bill,
I think your dyno chart bears out what we found at Laguna.
When I was shifting just before 6K the car pulled very nicely.
I don't think with the stock chip, changing your shift point is going to get you much since the HP and Torque begin to fall away above 5.5Krpm

Makes you wonder what it would be like with a little chip magic along with some intake mods (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[nine14cats]

I'm looking at chips right now. I haven't decided on one yet but I'm starting to look. I have heard of a few folks having a switchable hi-performance chip. You can flip between stock and performance.

Jerry told me he doesn't think there is much to gain on air filters since he has dyno'd both a K&N cone and a stock paper element with the box cut to let more air in. No difference supposedly. I have to run 1 5/8 inch headers per my class, so only the chip is left, since class rules state I can't touch the intake system from plenum to engine.

But bone stock.....what a wonderful motor!

Bill P.

[anthony]

QUOTE (nine14cats @ Feb 7 2006, 07:00 PM)

It is interesting to note that this motor was $7500 delivered to my door 2 years ago with 34K miles on it. I sold the 993 exhaust, the upper assorted hoses and engine tin for $700. The headers were ~$550, so I came in at 7350.

Was that a one-off great deal or is that the going rate for a 3.6?

[SirAndy]

QUOTE (anthony @ Feb 7 2006, 09:42 PM)

Was that a one-off great deal or is that the going rate for a 3.6?

(IMG:http://www.914world.com/bbs2/html/emoticons/popcorn[1].gif)

[DanT]

say what (IMG:http://www.914world.com/bbs2/html/emoticons/popcorn[1].gif) (IMG:http://www.914world.com/bbs2/html/emoticons/jsharp.gif)

[sixnotfour]

QUOTE

QUOTE (anthony @ Feb 7 2006, 09:42 PM) Was that a one-off great deal or is that the going rate for a 3.6?

That is a great deal, the older they get the less chance of a low mile motor.
In the last year , and 1st in line , of at least 3 other people for each one
87 3.2 6200
86 3.2 40k 6400
86 3.2 48K 6200
86 3.2 70k rough 2700

Sorry no 3.6 values , Be ready to purchase , Timing is everything (IMG:http://www.914world.com/bbs2/html/emoticons/burnout.gif)

[RON S.]

Thanks for the info,


I've got the exact same setup,always wanted to have an idea what my 6 was packing.


great job Bill,


Ron

[nine14cats]

Sorry about the late reply guys, I'm in Montreal on business.

Over the last 24 months the 993 3.6's have gone up in price. I bought mine from LA dismantlers. The 2nd 3.6 I had came with another car I bought. I have been watching e-bay and calling the normal cast of recyclers (LA Dismantlers, ect.) and the lowest price I got was $8800 delivered to my door with a 60K+ mile motor.

Private deals are probably better, but on the bird board there hasn't been many 3.6's coming up for sale, and when they do, they want alot. There is currently a carbed 964 3.6 freshly rebuilt for $12K.... (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)

When I bough mine, I called around everyday for about 3 weeks. I found the motor and had it shipped. PMS had a 48K mile motor in stock that he was willing to off for under $8K. But this was 2 years ago. I believe the prices have gone up. If you purchased a sub 50K mile motor for less than $8K, you probably got a good deal.

Bill P.

[michel richard]

Bill,

Where are you in Montreal ? I work right downtown, car for a bite of lunch tomorrow ?

Michel Richard

[Sideways]

QUOTE (Dave_Darling @ Feb 7 2006, 09:30 PM)

QUOTE (nine14cats @ Feb 7 2006, 06:00 PM) ...  I remember Brad saying the shift point for acceleration is about 500 RPM past peak Torque.... In theory, you want to shift where the power available to you in the new gear is equal to the power available in the old gear. So something like 500 RPM above peak power, not peak torque! If you shift before peak power, you will lose more acceleration by having to go through a taller gear than you gain by putting the motor close to its peak torque. Remember, stock 914-4 makes peak torque at 3500 RPM. Why do we shift at 5000? Because that's peak power. In a given gear, you accelerate the fastest when the engine is at its torque peak. But if you can choose a gear that runs the engine near its power peak, that will give you greater acceleration yet. --DD

The best shift point is different for each gear as the RPM drop for each gear change is different. The best way to determine the shift point for max accleration is with a plotted gear chart (RPM & Speed) for your transmission.

The optimum shift point drops the engine rpm back to peak torque at the engine (not the wheels as gear ratios affect this). As per your dyno plot your peak torque is at 5000rpm, therefore each subsequent shift will need to drop your rpm to there. As you move up the gears you will be able to shift earlier ie not have to rev as high(generally).

[ppickerell]

Bill,
What tranny are you running again?

[DanT]

Patrick, I am sure his new racecar has a G50. Not to mention I checked the thread where he announced his aquisition of Fritz. Yes it is a G50
It shifted very nicely with no shifter slop....not like a 915 (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

I have had Porsches with 901s (4 of them) One of those was connected to a 2.7RS motor
915 (1)
G50 (1)

The G50 is by far the best shifting of them all...period.

[ppickerell]

Problem is I have more money into a 901 (total rebuild, Guard 80/20 and billet int plate) than Bill has in his motor. Better to regear than sell and upgrade? Is a re-geared 901 so equipped as robust as a 915 or G50?

[ppickerell]

Sorry Bill,
(IMG:http://www.914world.com/bbs2/html/emoticons/hijacked.gif)

[DanT]

Sorry Patrick,
my 914-6 with the 2.7rs motor had short 3rd 4th and 5th gears.
I rebuilt the tranny 4 times in 5 years. Car was AX/TT almost exclusively, motor had too much torque for the tranny. I ran turbo half shafts so the tranny was the weakest link.
Many folks have run big motors on 901s but my experience and that of some of my friends says that it will be rebuilt much more frequently. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

Since you have a nicely built 901 I would at least give it a try. Just watch the low speed launches in 1st and 2nd.

[Borderline]

If you really want to know your exact shift points you have to plot your accelerating torque for each gear vs car speed. The final plot will be a series of arches. First gear will have high torque and as the car speed increases the torque will drop off to a point where it crosses the torque of 2nd gear. That's your shift point. The same applies to to to the other gears. That way you always have to most accelerating torque for any speed your driving. The shift points will vary depending on the torque curve of the engine and the difference between gear ratios. Its hard to set a hard and fast rule. I did this for my formula vee back in 0t he 80's and it wanted to shift just before 6k. Its not hard to do once you have the dyno sheet you know all the other numbers: gear ratiios, final drive ratio, and tire size. Of course, you don't want to take it over redline.

have fun,
Bill (IMG:http://www.914world.com/bbs2/html/emoticons/beer.gif)

[J P Stein]

How is it that HP /torque threads seem to turn into
tranny discussions? (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

Not being one to fight the trend........

My solution is to lay in a stock of 901 bits.
My engine is no torque monster, but in combination with big tires, surely puts a lot of overstress on a 901 under the right circumstances.

A long discussion with a local guru filled in a few blanks on my 901 knowledge. He says that the 901 can take more abuse than is generally acknowledged with one exception: heat. Heat absolutely destroys 901s.. end to end, says he and it's "worst condition" in a 914. Since I don't track my shitbox, heat is not a big issue. I have spares to cover the most common torque related issues, so I'll continue with the 901.....the expense of all was considerably less than the cost of a Wevo kit for a 915. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)