Performance cams in V-8 cars, carb and K-jet, continued

Basically a continuation of:
http://www.ferrarichat.com/forum/showthread.php?t=2788&highlight=performance+cam+regrinding

To review, the factory carb (32mm venturis) cams are: [email protected] with 349 lift. The factory 2v injected cars are [email protected] with .305 lift
QV and 3.2 cams have about 224 [email protected], the difference being QV lift = .305 and 3.2 having .346 lift

It came up in a pm today about what combo of venturi size and matched cam works well in a carbed car. The long held factory standard, the P-6 cam which basically was a 365 racing Daytona cam for the V-8. Using Carobu engine dyno data, a massaged 308 engine on 32mm venturis and P-6 cams will make 277 sae hp, but not be as streetable as the stock Euro cams which make about 235 hp at the flywheel, also on a 32 mm venturi. The 308 LM racing car produced about 300 hp on P-6 cams using 36mm in 40 DCNF carbs, although at an increased rev range with more internal changes. This is similar to an all out 308 racing motor from Carobu, with flowed heads (intake 166.2 CFM at 28"), 272/276 degree 11/9.9mm lift cams on 40 DCNF Webers which made 318 hp at 8K on the engine dyno, probably with 34mm venturi or the max size 40 DCNF venturi which is 36mm.

It's been said that you can pretty well carburate up to 260@050 for the street and still have a tractable engine
On another interesting calculation, Mike Pierce calculates that on a 3 liter engine, 34mm will support 320 hp
Norwood's did a 308 engine making 310 crank hp with 9K limit on [email protected] with lobe centers at 108, with 42 DCNFs, 34 mm venturis.

So, it seems that the 32mm venturis with hotter cams/porting will support up to about 280 hp, and larger venturi sizes above that, maxing out the 40 DCNF probably near 318 hp on 34 or 36mm venturis.

For a quick hp increase across the board in the K-jetronic 308 QV, you could drop in a set of 328 intake cams (exhausts are the same) with same durations, but more lift. Assuming that the QV events are compatable with K-jetronic, you could up the durations and lift on the 2v cars to at least the 3.2 QV specs and increase hp without injection tuning problems.

In my 3.2 QV on stock cams retrofitted 40 DCNFs and 34mm venturis, the engine makes approximately 285 - 290 hp due to better head flow. The same engine with ported heads, increased CR, similar duration cams with .360 lift and 38 mm venturis makes about 310 hp, may be a little more. So based on the previous numbers, I may be able to go down to a 36mm venturi, pick up some driveability and not lose top end. Also, I may be able to add some more duration, perhaps up to 250 and hope the power band (and the head flow) keep up. The fabled Frank Capo qv cams are about 250 in duration, IIRC...

Also, I'd really like to know the specs on a 348 cam if anyone has them, as well as other's experience in camshaft induction matching.

 

Here is the dyno sheet to that engine I told you about. To recap, the cams are inbetween a Euro/US '76-'77 cam and a P6 cam developed by Carobu which they have called the "Daytona" cam. The cam employs more of a duration increase than that of a lift increase which I would think would help a lot with cam wear issues a P6 may be more subject to. These cams also run with a 106 degree lobe center. This particular engine uses 10:1 pistons and 32mm venturis and is very streetable. Port matched heads and proper jetting are the only other modifications. Note the power curve rpm compared to that of a stock engine and that of a P6 engine. Also note that the amount of torque available is the same compared to that of the P6 engine.

This engine has an output slightly lower than a P6 cam engine, but not by much at all. 272bhp at the flywheel. This is very near the 10.5:1 P6 engine which was less streetable but had 277bhp with 32mm venturi (as stated by snj5, more could be achieved from this setup via other methods but streetability is nowhere to be seen)

first sheet is the "Daytona" cam engine. second is a P6 engine, and the last is a stock engine with port matched manifolds with '76-'77 cams.
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So, can anyone describe for us "neophytes" if all other mods being equal,(although not necessarily the same) for a streetable tune on a 2v engine, if you were to use EFI rather than carbs, what kind of output could we expect?

Essentially what I am asking is, "what is the maximum hp to expect for a tuned, (cams, hi comp. pistons, etc) 2v engine with an EFI conversion rather than carbs, and just to throw a curve, that can pass emissions"?

Please, if anyone can just answer the basic question without references to forced induction or a 328/348/355/etc. being the better option financially or otherwise. Lets just assume someone wants to build the fastest, streetable, normally aspirated, 308 2v car they can, without price being a real consideration.

 

So what's the price to get this work done? Also, what's the actual performance numbers? A substantial increase?

 

In a 2v engine, once you start getting above 88 hp/liter, that's pretty good. Remember that Ferrari's carb'd out-n-out racing cars were in the 90s-100 hp/liter.
It is widely variable on porting and just how wild a cam you want. Here is an example with TWM throttle bodies, P6 cam and 10.8:1 compression:
http://www.carobu.com/html/308_gt4.html
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Are we talking 2v with stock fuel injection or with custom injection such as projects others have posted with individual throttle bodies etc? The individual throttle body injection alone is a 15-20bhp increase in stock form while the stock injection is a serious decrease. More can be achieved via cams and pistons. A nice increase can still be had while being emissions friendly, but at a price.

 

To have someone else perform all this work for you would be upwards of $20k all in. Should you be a decent mechanic who takes time to make sure a project is performed correctly, it is very feesable to do on your own. I believe this forum is proof positive of that.

Figure $1200-1600 for a cam grind, another $1500-2k for pistons and rings, and another $1k+ for head work and port matching etc. The rest would be parts and your labor.

It is safe to say that you can expect a substantial increase in performance with a 270bhp 308. Estimate about the same performance figures as a Porsche 993/Ferrari 348ish, but with a much larger smile on your face due to the sound of the engine AND the fact that the headers, cats, valve guides, etc will not flake out like some of our other more other Ferrari brothers (no offense, I love other Ferrari's but I am old school like that)

 

I think the best people on Ferrarichat to talk to about straight EFI conversions are Luckydynes and Pizzaman.
Their threads on conversion are here (among other places):

http://www.ferrarichat.com/forum/showthread.php?t=212982
http://www.ferrarichat.com/forum/showthread.php?t=211219&page=3
http://www.ferrarichat.com/forum/showthread.php?t=175114

Good luck!

 

I don't know the Ferrari engines as well as others, but I would think an injected 2V car would respond well to a carb conversion.

With my Datsun common to take a later injected 280Z motor and convert to carbs (more power, easier to work with, etc.).

I know there isn't one answer, but if you converted an injected 2V motor to Webers and put in a hotter set of cams, what could you reasonably expect to get?

Once you start getting into head porting, costs skyrocket. For the backyard mechanic, I would see the above as easy to do with some gains over the quoted 214 crank HP of a GTSi/GTBi.

Thoughts?

 

Forgive me for paraphrasing your post, but your asking several questions that go in different directions.

To overhaul the 2V injected motor will cost $15-20K. Port matching the heads to slightly increase (but just importantly to equalise) flow and bumping valve size "just a tad" will improve it "a little" and cost a another $2K lets say, your at $22K.

If your doing an overhaul new pistons are included in the price. Some of these engines have been found to be a full point down on actual compression. A realistic 9:1 CR or maybe a tiny bit more, should pass emissions okay and if it was down to begin with would make a real boost in previous performance.

There was discussion of using the early 308 carbed intake cam, and that it will still run "okay" but emissions may become impossible. A custom grind may work, but will become awful expensive if it wont. Figure $3-4K for cams.

Most here claim an EFI system will set you back $8-10K. But in all honesty, even with EFI, getting a later 2V engine above 230 HP and being able to pass emissions is going to be difficult and your going to blow a lot of money. So between an overhaul with new pistons and valves, porting and EFI and all the other junk your sure to run into, you could be into the motor for well over $30K.

Seriously, the cheapest thing you could do would be to install a good used 328 motor, it will bolt right up to your current gearbox. Or do some engine cutting and drop a 348 onto the gearbox and plumb it in. If your paying to have it done, most likely none of the above options will cost less than $20K. But they shouldnt cost $30K either. And either engine should pass emissions like a breeze. Short of a turbo or blower on that 2V, you wont be able to make that kind of power any cheaper.

 

You then basically have the original spec Euro 308 carb engine with about 240 hp or so depending on the cam.

And, of course, the sound and especially the improved throttle response will make it seem like more...

 

Egads! Is that top to bottom brand new everything?

 

Yeah. It adds up fast. Even faster if you dont look at the reciepts

 

This applies exactly as the lyrics of the terrific Robert Palmer tune, 'Simply Irresistable':

"She so fine, there's no telling where the money went..."

Most expensive thing to do: pistons
Second most expensive thing to do: port/polish

Cheapest thing to do: muffler
Second cheapest, simplest & best bang for the buck: bolt on a set of Webers

 

How easy is the Weber conversion?

 

For a 2v, all bolt on and about $2 - 3K

Carb manifold/linkage + gaskets
4 x 40 DCNF-12 jetted to 32mm venturis, 140 mains F24 200 a/c and 55 idles and linkage pieces
low pressure fuel pump, new fuel hose
air filter(s)

That's it. Just remember to jump the fuel power relay so it gets juice when the key is on.


<edit>
Speaking of costs, if you want to regrind to hotter cams, figure on about $60/lobe. You can get by with just doing the intakes as typically the exhausts are ok.

 

As I am thinking of getting a 308, to me the GTSi/GTBi seems the way to go. Could snap one up (relatively) cheap, then do this conversion / cam grind at a later time, if desired.

The biggest "fear" I've had with the GTSi/GTBi is that the early FI units are quirky (hearsay, no facts on my part), but seeing that a carb conversion isn't overly difficult, I'd go that route immediately (I like carbs, I guess I am old school)

Thanks a bunch!

 

The old K-Jetronic FI units are actually pretty brilliant, and excellent for what they were designed to do, but they are not a performance system being aimed toward the early emissions control standards. I think for what they are, the GTBi/Si and Mondial 8 are screaming bargains right now when used as designed, bespoke street GTs and not as boy racer wannabes. Still simple without a lot of computers, and many upgrades and support available.

I think your plan is quite good. Get a K-jet 2v car now while inexpensive, retrofit Webers for about a crisply responsive 20 hp, then later you can do cams at your convienience. These "Daytona" cams from Carobu look like an excellent option for a street car, and the carbs should adjust just fine to them.

 

been reseraching this question a bit now. Can someone tell me if the '76-'77 USA version manuals are a typo regarding the exhaust cam duration? Is it really 10 more degrees than that of a Euro cam? I am pretty sure this is a typo but I would like to confirm it to be sure. US says: exhaust opens 36 BBDC and closes 38 ATDC. Euro states opens 36 BBDC but closes 28 ATDC.

 

My manual agrees with your numbers.

 

I have checked the Euro manual as well but I believe the US manual exhaust duration figures to be a typo. Pending someone explaining to me why the exhaust cam has 10 degrees more duration in a US car? The '78-'79 US cams were tamer yet but still did not employ the exhaust duration the early cams are quoted to have (rules out doing it for emissions).

Artvonne? Bueller? anyone?

 

Thanks for this information.
Around 260hp sounds pretty good for a normally-aspirated street 308.
So, for this particular example:
1. Can it pass emissions?
2. I assume this includes porting/matching, does it also include anything else like bigger valves?

Thanks.

 

Emissions testing is so widely variable it depends on your state.
This is with stock valves I believe.

 

Bluemel V-8 book has the same cam spec differences. That might be a typo too but at least it's consistent. There needs to be a third party to confirm.

 

Without digging, IIRC all the early 308 cams have the same duration as listed for the US cams. It is my belief that the numbers listed for the US cam are the same as for the euro. The problem is that there just arent any (or very few) dyno runs that have been posted for early 308's.

On Carobu's website, its interesting that the P6 cammed 308 GT4 motor with TWM throttle bodies (electronic fuel injection), slightly higher compression (10.8:1 vs 10.5:1), and coil on plug ignition, produced "less" power than the P6 cammed carbed 308 with points ignition. With all the hype about electronic ignition and electronic fuel injection making 10% more power for each system, I would have expected that GT4 motor to be nearly 50 HP above the carbed version. I am guessing a TWM setup and installed could set you back $10K, and another $2 or $3K for the ignition? $13K to make less power? Wheres the beef? If the carbed motor made 277 HP, I would have expected the TWM motor to at least reach 300. Lotta money to blow for no gain.