Best way to get 275 HP from 3.0

[moparrob]

So I have a recently rebuilt, stock, 3.0 from a 1978 SC which is running stock CIS injection. I think these put out around 180 HP if I recall.

I am interested in increasing HP and know that either (properly) converting the motor to a turbo setup or going with a 3.2 or 3.4 motor would easily get to 275 HP or more, but at a cost of around $20,000. That is a bit high for the current budget.

I haven't seen a lot of discussion though on getting significant additional HP gains from a stock, or lightly modified, 3.0 though. Has anyone come up with some reliable mods to obtain increased power without risking ruination of the engine?

I thought of a supercharger but don't see any kits for the 3.0 at present, only for 996 models.

Any info would be greatly appreciated.

[fintstone]

If you could find one of the old 3.0 Supercharger of Knoxville Kits, that would be the ticket. Otherwise you could build your own supercharger setup.

Personally, If I wanted that kind of horsepower in an air cooled, I would probably sell the SC and buy a car that has already had the 3.2 or 3.6 swap. Stock cars are appreciating faster than the more highly modified ones...and you could probably get a hotrod cheaper than building one (considering what you could get for your car).

[DWeg1998]

The best way is not to buy a 35 year old car

[jmz]

cams, carbs, compression, airflow. good hands to assemble it, or the dollars to spend.

[Steve@Rennsport]

Originally Posted by moparrob

So I have a recently rebuilt, stock, 3.0 from a 1978 SC which is running stock CIS injection. I think these put out around 180 HP if I recall.

I am interested in increasing HP and know that either (properly) converting the motor to a turbo setup or going with a 3.2 or 3.4 motor would easily get to 275 HP or more, but at a cost of around $20,000. That is a bit high for the current budget.

I haven't seen a lot of discussion though on getting significant additional HP gains from a stock, or lightly modified, 3.0 though. Has anyone come up with some reliable mods to obtain increased power without risking ruination of the engine?

I thought of a supercharger but don't see any kits for the 3.0 at present, only for 996 models.

Any info would be greatly appreciated.

While its not difficult or challenging to get 275 BHP from a 3.0 engine, its a non-starter if you need to be smog checked to register the car for street use.

[saxen]

1995 3.6 swap with vram intake manifold. Under 20k and stock reliability

[moparrob]

All good points.

Dweg - I disagree, and look forward to the challenge of applying new technology to improve an old design - but that is just me.

JMZ - I am familiar with the basics, and was actually thinking about staying away from carbs for this build. Perhaps a modified CIS system or stand alone EFI.

Steve- anything I do here in CA will not be smog legal, but I am not going to let that stop me. Even if I have to swap in a stock engine every 2 years (but I don't think I will need to...) What were some of your initial thoughts for such a HP goal?

Saxen - I like the idea of a 3.6 swap, but I am assuming a 20 year old engine will need a full rebuild so that might push the project cost into the $25k realm if that happens.

[Steve@Rennsport]

Originally Posted by moparrob

Steve- anything I do here in CA will not be smog legal, but I am not going to let that stop me. Even if I have to swap in a stock engine every 2 years (but I don't think I will need to...) What were some of your initial thoughts for such a HP goal?

You will spend $25K to get a reliable 275 BHP that runs on 91 octane fuel so if budget is an issue, you'll need to scale back your power requirements.

Further, close-ratio gears may be necessary to keep this engine in its most productive powerband for best performance so I'd budget for that as well.

[NY65912]

Oh the slippery slope!

Higher CR, DC-40 cams, 46mm PMO's or ITB's, headers, etc, etc.........

It's really based on budget.

[gliding_serpent]

How fast fo you want to go? How fast fo you want to spend?

For me, 3.2 vs 3.6 was a tough desision, but getting 250hp in a 3.2 is easy. If i had a 3.0 and wanted 275, i would go 3.6.

A local sc is 2400lbs with a 300hp 3.6. It is faster than the modern turbos. Power to weight is 8lbs per hp. Nissan gtr is 7.0 lbs per hp.

[T77911S]

Originally Posted by Steve@Rennsport

You will spend $25K to get a reliable 275 BHP that runs on 91 octane fuel so if budget is an issue, you'll need to scale back your power requirements.

Further, close-ratio gears may be necessary to keep this engine in its most productive powerband for best performance so I'd budget for that as well.

thats what i was thinking and i kind of had to laugh when you said you diid not want to spend 20k.

i started pricing the build on my 3.0 and with all the machine work, twin plugging it, still running CIS is was going to be near 20k with me putting it together.
probably in the 15k range actually.

i sold everything and bought a 930.

[fred cook]

You should listen to Steve! He has many years of experience rebuilding and modifying Porsche engines. To get to the power levels you want will cost you at least $12-15k just in parts! One thing you can do to help with the power increase is to build a 3.2 or 3.3 liter short stroke engine. Displacement = power. Also, HP is in the heads, so start looking for a good set of twin plug heads with big ports!

[NY65912]

My 3.0 in my track car put down 256 at the rear wheels after all the mods.

Then that wasn't enough and I had to build a 3.8. In a 2400lb car that was scary. The 3.8 put down 357 on the dyno....415 flywheel?

I sold the car cause I was too scared of it.

[trader220]

Even with a 3.2 if you want 275 bhp its going to run you close to $20 grand.

[tobluforu]

If you were to sell your car right now, could you buy what you wanted already put together. It might not be the same year, etc. but if you added 10-20 grand on top of what you sold your old car, maybe this is the easiest way?

[gliding_serpent]

Even with a 3.2 if you want 275 bhp its going to run you close to $20 grand.

I hope not. ;-)
240 is doable with headers, sports exhaust, chip on 91 Octane. Cup airbox gets about 5hp on a stock chipped 3.2.
964 cams get 5-6 more hp, but you need $$$ to get it in.
Overbored cylinders and 3.4 pistons probably run 2000$ to 5500k that run on a single plug and 91 octane.
Twin plug costs near 3k i estimate, but i am guessing on machining.
Extrude hone 600-1k i guess.
Add more power if willing to up compression and octane.
The big issues are the cost of the top end work and all of the "while you are in there" items.

I bet your 20k is about right... 275 hp or abouts, with a fresh known engine.

I priced about 25k for a 3.6. No guarantee the 3.6 is fresh however. Ymmv.

Thus at 25k for the hot 3.0, i would go 3.6 as the 3.0 would have a dhorter life to get that power. The 3.6 can get 300hp easy with chip and exhaust, and minimal stress.

[moparrob]

All very good advice. It looks like I will need to re-adjust my budget if I want to go that fast.

Is there any practical difference in drive ability of a stock 3.6 transplant versus building a modified 3.2? It seems like the cost would be similar.

[Iciclehead]

Another alternative is to consider the power to weight thing.....

Are you up for cutting the weight of your car down? Things like getting rid of AC, fibreglass panels (fenders, doors, sunroof, hoods), serious run at extraneous items in the interior such as trim.

Truly a guess, but I suspect that taking 200lbs off of the car and perhaps having the driver diet to lose another 50 lbs is sort of like adding 25 hp (assuming 10lbs/hp).

Dennis

[NY65912]

Originally Posted by tobluforu

If you were to sell your car right now, could you buy what you wanted already put together. It might not be the same year, etc. but if you added 10-20 grand on top of what you sold your old car, maybe this is the easiest way?

Agreed, buy someone elses project with the mods already done

[911SauCy]

Originally Posted by gliding_serpent

964 cams get 5-6 more hp, but you need $$$ to get it in.

I've seen this figure posted before and it's got to be the most depressing fact about 911 engine modding.

5-6hp...that's truly laughable, never mind the $$pend to swap cams.

I swapped a pulley on a supercharged Buick V6 and got 35hp to the wheels for $185...