Who has manged to reach the 300 hp mark

[bbaer6676]

I am looking to build an engine capable of reaching 300 hp with natural aspiration. Who here has managed to pull it off and what did you use. Im going to start with a 3.2 probably, could it be done with a 3.0? This would be using pump gas and I would like to keep it somewhat reliable if possible. Thanks.

Brian

[Chocaholic]

I think you're odds would be better to start with a 3.6 V-ram. 282 hp bone stock. Just a thought.

[Alan.UK]

I am aiming to get pretty close to it, and will know in a few months when the new cams are here and I go back to the dyno. The motor is a SS 3.2.

Alan

[Steve@Rennsport]

Brian:

Its very possible to hit the 300 HP (flywheel) figure with a 3.0 engine if its properly configured.

You can use pump gas as long as you use twin-ignition.

Reliability/longevity is in the hands of the builder-operator and in the choice of parts used,...

[1980 911 sc]

97 3.6 varioram,
cone air filter,
1 7/8 equal length headers,
DME flashed,
custom muffler,
this is a solid motor witha 50K mile+ life
worth 295-305 (depending on the weather)

more to do,
cams,
head flow,
lightening valvetrain to increase RPM
bump to 3.8,
ITB,

worth 350+ but how long will it last?

[Dennis Kalma]

Have not yet started the build, but I am targetting 300 hp using the following set up....I hope.

3.4 litre (98mm Mahle 10.3:1 pistons, 74.4mm crankshaft
Carillo rods, Supertec head studs
S camshaft
Dual plug
TWM intake manifolds, engine management system (not decided yet)
1979 SC heads, light port and polish
SSI heat exchangers, factory muffler (dual inlet of course)
CoP ignition (12 coils of course)

It will go into my '89 project car, 6 speed transmission.....

Dennis

[bbaer6676]

Steve,

What kind of 3.0 configuration would you suggest. Twin plug makes sense.

[Steve@Rennsport]

Brian:

A 300 HP 3.0 would look something like this:

1) 95mm Mahle P/C's at 10:1
2) Early large-port SC heads; properly prepared
3) 120/104, GE 80 or equivalent cams
4) 46mm PMO or 48mm ITB & Engine Management (we make our own)
5) 1 5/8" headers with a proper dual-in/dual-out race muffler
6) Twin-ignition, of course

Remember, the "Devil is in the Details" so quality of assembly and attention to many details make the difference in these situations,...

This is a simple list, but you'll get the idea,.....

Close-ratio gears are strongly recommended here!!!

[Facey]

hey
i'm running ~320hp n/a.
thats like 280 rwhp (i made 278.x)

3.5L
100mm Mahle P&C's
74mm crank
big heads, 46/44 intake/exhaust ports
twin plugged running a electromotive ignition (6 coil)
external oil cooler
1 3/4" B&B long merg headers
M&K exhaust
a mod-s cam (dyno and air/fuel show that this cam is not sufficent for this engine, however for my mainly street use, and lack of funds this is what it is for now)
46mm weber IDA's, need a little tuning, running too rich, probably 8-10hp on the table there alone
~9.x:1 CR (not what i wanted, but it does make sense, loose a few hp gain a bunch of saftey)

this engine makes for a rocket of a street car, and its fun to run with the turbo guys, though a similarly modded turbo will out accelerate.....damn....
it is very torquey and loves to rev (though i have a limiter set @ 6700)

[randywebb]

and think about the "streetability" of this idea if that is a concern

I did and went with a puny 250 hp out of a 3.2L

[JP911]

Dennis-
Your build list looks great, right up until the SSI part. IMO, SSIs will be very restrictive for what you're building. I'm sure Steve could provide some better exhaust recommendations.

[Steve@Rennsport]

Randy:

You are right,... Since Brian specifically put his questions into a 3.0 litre context, thats how I framed my reply. Without question, a 300 HP 3.0 will not be as docile as the same configuration in a larger displacement; 3.2, 3.4, or 3.5. When one expresses specific HP goals, there are compromises to be made based on displacement.


Jon:

Right again,... SSI's are FAR too small for a 3.5 or larger motor and we've seen 25+ HP losses using those on these big engines. I do have some other ideas that work VERY well,....

[ted]

Streetable stock induction 993 non VR 3.6 with cams, 306hp at the rear tire.
That was with a chip made for 100 octane, I also have a 91 octane performance chip I got from DWSD.
Go for a streetable 325hp.

[randywebb]

Thanks Steve - I know you know, but just wanted to make sure it got out on this thread for all the viewers.

Glad you are back in operation also...

[JeremyD]

I have 287in a 3.4 (corrected) - very streetable idles nicely
and not out of the world expensive
revs fast off a 3.4 base

[Dennis Kalma]

Jeremy...what are the specifics of your 287 hp 3.4?

Jon/Steve...with regards to the SSI's, I really need to have heat in the car (Canada is cold, plus the wife and I will end up winter touring in the car), so what real alternative is there? I keep on wondering why the SSI guy does not make sets with the larger pipes for the larger displacement engines?

Dennis

[RLJ]

My short stroke 3.2 came up with 296 or 8 HP at the crankshaft IIRC.

My motor build list is close to Steve R's list. His buddy and mentor built the motor, so I guess his list should be close to what I ended up with

One of the big differences in my motor and "the list" is Dick used a set of 3.2 Carrera heads that he had already dual plugged I think the date on the castings was 1988.

IIRC the compression is right at 10.25:1 so that is right on the edge or streetability for pump gas. The 120-104 Web grind cam sounds like a small block Chevy with a "Duntov" fuelie cam.

So 300 HP is real. The dollar figure to get there is steeper than HP curve IMHO.


Best wishes for the New Year,
Randy Jones
1971 911 "Iris"

[JP911]

Dennis-
I needed heat with my 3.5 and decided to go with 993 heat exchangers with the flanges flipped. This setup gives you larger diameter, but I don't think they're quite equal length. Connecting heat on these requires some creativity and you'll need a custom muffler. The other options would be GHL or B&B headers with heater boxes. The 993 HEs work well, but the GHL or B&B setup would have been more plug-and-play, albeit a bit more pricey.

[Steve@Rennsport]

Originally posted by Dennis Kalma
Jon/Steve...with regards to the SSI's, I really need to have heat in the car (Canada is cold, plus the wife and I will end up winter touring in the car), so what real alternative is there? I keep on wondering why the SSI guy does not make sets with the larger pipes for the larger displacement engines?

Dennis

Dennis:

Many people feel the same way about having heat & defrost capabilities so we have GHL make a special proprietary header/heat exchanger for us that is 1 5/8", equal-length, and uses a factory type muffler (flange spacing).

While not inexpensive, its very durable and works really well on these larger motors.

I've spoken to John Daniel (owner of SSI) at length on this subject and the costs of tooling up to make 1 5/8" versions of his excellent product cannot be realistically recovered at this point. Thats why we looked for other solutions to this issue.

[NY65912]

The little hot rod 3.0 that was built for my DE car is as follows;

PMO 46mm carbs
JE Pistons
10:1 compression ratio
Ported heads
Dougherty DC40 cams
SSI's
MSD ignition
Competition valve job
Racing valve springs
TI retainers
993 headstuds

We made 255 rwhp plus 15% loss equals 300 hp at the crank.

This engine is very drivable on the street as well. Timing is aorund 30 degrees overall. Power up to 7000 rpms.

I am very happy with this combination.