Question regarding 3.0L performance

Axeman · 07-26-2002, 02:16 PM

I put a 1980 3.0L with 1979 heads, Webcams, SSI's with pre-74 exhaust in my 1975 911s. It has pop-off valve, I'm putting in a twin-turbo 993 oil cooler in the front. Supposedly this engine will put out about 200-210 max as far as horse power. What else can be done to increase the HP on the 3.0L but still keep it reliable?

Thanks,
--Michael

surflvr911sc · surflvr911sc's Garage

I probably not a whole lot of help here, I have a wopping 180hp of pure fun out of my 3.0. Oh well, I still love it.
How you doing Michael? Back home?

Wayne 962 · Wayne 962's Garage

Still running CIS? I hope you put the right camshaft in there?

-Wayne

Axeman · 07-26-2002, 03:34 PM

Wayne, still running the stock CIS, as far as the cams it has the 20/21 I believe ( it was fully rebuilt by Eurosport, 1980 case, '79 heads, webcams, new Mahle 9.8:1 P/C, SSI, Carrera tensioners) I bought it of one of the board members. Runs strong, I'm just wondering if I can get more power, I mean first I should probably learn how to fully drive it since it's my 1st 911!!

I thought it was possible to get a lot more HPs out of these engine. Any thoughts? I will probably go to a 3.6L eventually when I have the cash. In the meantime the car has been on a serious diet, it has the C2 fiberglass rockers and F/R bumpers, no A/C, RS doorpanel, no power anything except for sunroof, Corbeau seats, etc...so I'm pretty sure I'm 250-300lbs lighter than a stock one. Does anyone know how much a '75 weighs stock?

Ryan,

Thanks for asking, yes back from the hospital, but the pain just doesn't go away and I'm still bleeding a little from my bladder which is no fun!

Are you local here by the way? I live in Agoura.

--MIchael

surflvr911sc · surflvr911sc's Garage

I live out in Highland, by San Bernardino and Redlands. Are you feeling up to going on the mountain drive with us Sunday?

Sunday Mountain Drive

Glad to hear you're home, take care of yourself.

Elombard · 07-26-2002, 04:21 PM

Man - you are hard core, my 73' with and SC motor (stock with SSI) is scary fast. You are an animal. I would like to see how you do the TT oil cooler up grade, post pics when you are done.

Go to TWM throttle body fuel injection and crank fired ignition, not really that much HP but webber like throttle response with out the tuning. Then you can go to crazy cams.

Have fun

Axeman · 07-26-2002, 04:22 PM

Ryan,

I would love to go, but my car still doesn't have the oil cooler installed and I sure don't want to fry the new 3.0L I bought!!

Believe it or not, I have barely driven this car since I bought it in April. As soon as I got it it went in the body shop for the new paint, then I ran across the motor on Pelican and bought that, so it was in the shop right after getting painted, now that I have had it back for a month, I've been re-doing the whole interior (new seats, carpet, dash, panels, etc..), had to get new tires, and realized that the car is not driveable in the Valley when it's 110 degrees with no oil cooler!! Spent the last 3 weeks looking for the oil lines for (my car didn't have anything), just found them last week cleaned most of it, now I gotta take the car to my mechanic next week so he can install the 993 TT cooler, but he's been busy building a real GT-3 for a customer..so as you can see it's frustrating to look at my baby and I can't even drive it!!

Hope we can do another drive soon (maybe the Pelican drive?) so I can meet all of you and you can teach me a few things..where should I go to take driving lessons so I can really handle the 911?

--Michael

Axeman · 04:29 PM

Quote:

Originally posted by Elombard
Man - you are hard core, my 73' with and SC motor (stock with SSI) is scary fast. You are an animal. I would like to see how you do the TT oil cooler up grade, post pics when you are done.

Go to TWM throttle body fuel injection and crank fired ignition, not really that much HP but webber like throttle response with out the tuning. Then you can go to crazy cams.

Have fun

HAHA..trust me I'm anything but hardcore! It's my 1st 911 and it will take me probably years before I have the guts to really push it. The car is fun as is, but I'm the kind of people who really likes to be "pushed" in the seat when you step on it, and it just won't happen with a 180-200hp engine. I'm not a "top speed" kind of guy, but would love to have a Porsche that does 0-60 under 4.0 sec someday!

--Michael

surflvr911sc · surflvr911sc's Garage

We'll definitely do it next time. I'm looking forward to seeing that car of yours. I would love to do new paint but I'm going to do a rebuild next year (I hope) , one thing at a time.
Haven't taken any driving lessons yet, owned the car for five years. I have learned a few things out on the road, lessons of experience I guess.

Superman · 07-26-2002, 04:41 PM

The engine you described is probably just about as efficient (powerful) as 183 cubic inches can be without super- or turbo charging. I'd agree that for nearly all of us, the best source of performance increases is seat time at a track, preferably with an instructor.

The other thing you can do is lighten the car.

Axeman · 07-26-2002, 04:55 PM

Superman,

You guys know what my car weighs stock? It's a 1975 911S. I thought it was like 2600-2700lbs right?

--Michael

TimT · 07-26-2002, 05:10 PM

The engine you described is probably just about as efficient (powerful) as 183 cubic inches can be without super- or turbo charging.

I will disagree with that statement

A rule of thumb amongst tuners is 100 hp/Ltr for normally aspirated engines

In May I spent 2 days helping a friend set up the fuel management and dyno tune his 3.4L engine. When we achieved our best dyno pulls we had 311 RWHP, factoring in 15% for losses, wheel slip on the dyno etc, that works out to 367 HP at the flywheel.

I have a 2.2 Ltr car my car dynoed at 150 RWHP which is ~172 hp.

following these trends a 3.0 should would be capable of at least 300 hp

Axeman · 07-26-2002, 05:23 PM

Anything close to 300hp would be awesome! Hell they get 260hp out of a 2.7 RS Spec right? What can't we get the same out of a 3.0L?

--Michael

TimT · 07-26-2002, 05:25 PM

read my post, you CAN get 300hp, it all depend on your checking account

Superman · 07-26-2002, 05:57 PM

Well, the rule I have been most familiar with (perhaps from a low-tech era) is one hp per cubic inch. That's good. Two hp per CU is tops. Or was.

I would still argue that with a few mods you can take the 3-liter Porsche engines to 1.5 (274 hp), but that taking them much higher than that, without pushing air in them, is difficult at best. An engine is an air pump. When it pumps a given volume of air, it is only capable of so much HP. Higher compression squeezes out more horses, but three liters is three liters. How many cubes in the 996 normally aspirated engine versus how many horses. I think those engines are 4-valve units.

Also, smaller engines are more efficient. The 'rule of thumb' measures we have touched on are not linear. Larger displacement gets diminishing returns. Imagine, those DOHC 2-liter go carts Porsche once built!

Anyway, I am intriged by this discussion and hope to learn more about the maximum horses we could possibly get with a normally aspirated, SOHC 3-liter boxer engine. I'm not sure I believe they can make 350 horsies. If so, how?

dd74 · 07:43 PM

I know I've asked this before, but can't find the thread - I'll print this thread out, though that's no guarantee, either. Nonetheless, what sort of preventative work needs to be done when one puts 20/21 grind cams in their SC motor? Secondly, with 9.3:1 compression and backdated exhaust, what sort of horsepower can I expect? I know Noah's ran 9.5:1 and Euro versions have 9.8:1. I was thinking of installing just the cams and leaving the pistons stock. Is leaving the 9.3:1 pistons in the motor a feasible idea?

Thanks in advance for any and all responses

dd74 · 07-26-2002, 09:42 PM

Hmmmmm...tell me more, Warmonger...how's it work?

Superman · 07-27-2002, 07:38 AM

No, you don't need any special parts to accomodate the 20/21 cams. Indeed, i doubt if more than about 10 hp is achieved, peak. But what those cams WILL do is make your power band twice as wide, or more. they make the car remarkably more 'driveable'. While you have the rocker shafts out, it's a good idea to use the special seals to prevent them from leaking after reinstallation.

I can agree that carbs improve throttle response. TR is an elusive thing, but when you have it, you notice it. A carbureted car would be more fun to drive than CIS. It has been my understanding that carbs cannot atomize fuel better than injectors can, so they cannot produce more ponies, but of course there are going to be exceptions.

My horsepower beliefs are more conservative than most, it seems. With the 9.3:1 pistons, 20/21 cams, backdated exhaust, advanced but not knocking timing (thanks, JW) and fresh valves and rings, I could claim 230 hp, but I don't think I'm there. I'd estimate closer to 210. I know that my engine can go past 300 hp with radical cams and more displacement (3.2L), but at its current displacement (3.0L), I think it's a bit difficult to get above 260. A normally aspirated 3L engine would just about need to burn nitro methane to make 400 hp. So, if you can't get happy with 230 drivable horsepower, then you need the 3.6L transplant. They can make 300 drivable horses.

Axeman · 07-27-2002, 11:23 AM

Wow so much information! Thanks everyone for your input.
I just wanted to go back to the weight issue for a moment. I mentioned in my earlier post that I've tried to lighten the car as much as possible. The stock bumpers are gone (almost 100lbs), A/C is gone (about 120lbs I believe), door panels are R/S, Corbeau seats, no power anything except for sunroof. Anyone has the exact weight for the 1975 911s from the factory? I'm guessing I must be somewhere around 250-300lbs lighter. I don't think there's much else I can take out as far as weight, I don't even have a stereo in there yet!
Also you guys mentoned that my engine with the current setup should be around 230hp. That seems really high, I've been told that even with the 20/21, 79 heads, SSIs this engine won't make more than 210hp. Another person told me that to gain a few more hp I would have to get the euro intake and fuel system and distributor as well. Any truth to that?

--Michael

304065 · 07-27-2002, 11:43 AM

A few data points I found interesting

1967 911R (typ 901/22) 210 HP/ (80 x 66) 1,995 cc = 105 hp/l
1970 911S-T (typ 911/70) 270 HP/(86.7 x 70.4) 2,492 cc = 108 hp/l
1972 911RSR (typ 911/73) 308 HP/(92 x 70.4) 2,808 cc = 110 hp/l
1975 3.0RSR (typ 911/75) 310 HP/(95 x 70.4) 2,994 cc = 104 hp/l
(same bore/stroke as SC motor)

and just for fun,

1976 935 (typ 930/72) 590 HP (92.8 x 70.4) 2,856 cc = 207 hp/l

It looks like the best the factory was ever able to do without turbocharging was 110 hp/liter. It's hard to speculate as to whether that was the absolute maximum the design could produce: even the racing engines were designed for longevity (in racing terms, which probably means 30-50 hours).

Is it possible to improve on these numbers through modern engineering and technology? With electronically controlled fuel injection and crank-triggered ignition, maybe. I doubt we could do much to improve on the factory's titanium rods and lightweight valvetrain, though.