Upgrade or Stock?

Right. Enjoy your ICE car for what it is and the era it represents. I have zero interest in ever owning a Plaid (didn’t even accept the offer of driving one) but have to respect the engineering and performance.


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Funny, even though electric cars were among the earliest "engines" in automobiles, it's taken 120 years to get batteries to the point that they are actually practical. I'd buy one in a second if:

1. the range was 800+ miles (we do a 780-mile one day trip several times/year in our Hyundai Santa Fe) or,
2. Recharging was as fast as getting gasoline.
3. I could convince my wife to sell her MB S550.

 

I’ve never heard about that. Those mods must have been pretty rare as I’ve never seen a car for sale with them mentioned. I wonder if there’s a thread here about it.

Do you know where I could find the exact specs of those modifications? One of my oldest friends was a dealer tech in that era (and still is!) and I’d like to discuss it with him if I had more information.

Thanks,

 

A quick search here for "P6 cam" pulled up 5 pages of results. The specs I have in my notes are 270 [email protected] lift, .360" lift. I THINK its the same spec as a daytona cam for the V12s. and again I THINK the pistons were 11:1 but that is from memory. That is all I know and that I read here years ago but I do know there were a couple guys that used to post here that had that setup and it was a love/hate relationship, the hp is good and it pulls to over 8k, but the drivability really suffers as that is a lot of duration for webers to deal with so I've read of people going back to the 76/77 cams which are more like [email protected]" and much better mannered on the street.

In my mind those are a mistake with webers but fine cams paired with EFI so you can control the mixture at low rpm. Motorcycle slide type carbs can also handle that duration pretty well, I ran exactly that duration in a Harley on the street with no issues, the slide is basically a variable venturi so you get good velocity even at low rpm and long duration cams are fine. With webers though to make low rpm work you need to down size the venturis but that chokes the high rpm which wants upsized venturis so fine at the track above 4k but suboptimal for street driving.

 

A description of the "Sprint Pack" at http://yorkshireferret.blogspot.com/2016/06/ferrari-308gtb-last-throw-of-2-valve.html .It includes carburetion calibrations and settings that make the modified engine more "streetable."

 

Very very helpful. Thanks to both!

I’m betting those Sprint Packs weren’t available in the US market. I think Porsche dealers stopped selling the 911 sport kits here in 1968.

Jack.

 

Is there a simple way to increase 20% HP to a 88 328 ?

 

Replace it with a 348 is the only simple way I know

Lose the CSI in favor of EFI is probably 25hp but once the CSI is gone a lot of the limits it imposed are also gone so your free to spice up the cams and you can pick up 20-40 there. Together its maybe $5k-$7k in parts, something like that. This is basically exactly why the 348 makes more power than the 328, you can even use the 348 cams if you want to stick ferrari parts....I guess you could use the intake too but I don't think it will fit under the hood and the ports are a little bigger on the 348 heads so you'd want the grind you ports to match the 348 intake gasket, I've ported 1/2 dozen sets and always start by matching the 348 intake gasket. Porting can add another 10% with a factory intake, maybe 20% with ITB conversion so that is another path or a path to more like 30-50% gain with cams and EFI but another $2k-$5k depending who does the porting and to what specs.

Boost is the other path...20% is 3-5 psi I guess so no intercooler or anything like that needed. I know people have added boost to CSI but I don't know enough about tuning that to even guess A small turbo and some plumbing maybe $3k-$5k parts, if you also do EFI maybe $2k-$5k more depending but then you can run much higher boost.

 

My GT4 had the Borgo pistons and ANSA exhaust. Cam profiles were measured as consistent with 365GTB/4 but I think this may be stock for early GT4s. P6 was more aggressive from threads I have read.


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There was (is?) a supercharger kit available from 928 Motorsports for around 7K. Some years back I nearly bought it twice and both times the money I had earmarked for it ended up going to the IRS at tax time! IMO, it's the only way to get a substantial power increase out of one of these engines at a reasonable price. If they were ford/chevy/mopar motors I'd go the usual hot rod route with internal engine changes but the cost to do that on these engines makes it totally unworkable for me.

 

Interesting info. I have an 82 GTSi that one day I'll pull and rebuild the engine on some day. I suspect these cars would be a slightly nicer drive with around 30-40hp increase, and probably sound that little bit better. If that can be achieved without changing the stock appearance of the engine then it becomes a "while you are in there" possibility.

The P6 cams add a lot more duration and hence overlap over the stock cams, which tends to create high end power at the expense of idle quality. Did I read somewhere that the standard cams fitted in the 2V injected cars were deliberately very mild as there was concern that too much overlap would disturb airflow through the metering plate? Perhaps I imagined that. The article addresses that point directly for the carb cars.

Does anyone know if the fast road cams that Superformance sell are these P6 cams?

 

While I know little about what mods are available for the 2-valve injected engines, from my drive of a 308 GTSi and Mondial 8 (same engine), it seems like the emphasis in any such endeavors should prioritize improving torque over increasing HP.

 

I have installed a sprint pack and had it on the dyno, twice. It was an on/off switch of an engine making, iirc, 225bhp or so at the wheels. Stock I made 199bhp at the wheels. I used 34mm chokes and F36 jets and some other jet changes but cannot recall what now. The P6 cams with Borgo pistons are just about unlivable pigs.


That all said, I have always been shocked Ferrari never used the Dino/Daytona profile cam in 308 heads in some optional back-door increased performance capacity. The stock (!!) Dino/Daytona profile is about 252 duration @ .050 and some .365 lift (76-77 308 cam is some 235 dur @ .050 and .345 lift). This would make for an outstanding, preferably high compression, performance street cam in a 308.

 

This is what I was on about earlier....I'm certain that setup wants the 36mm chokes and even then the carbs will be costing hp.....but to make it drive nice the 34s are too big with those cams.

With more modern carbs or efi It should drive fine and also make a bit more power

I think there aftermarket options for that? I think you're right that [email protected] is probably about the limit for weber.

I would add that head flow and valve size are also quite important. Heads that flow more need less duration so ported heads with the 76/77 cams will act about the same as stock heads with [email protected] cams. High velocity high flow heads with less duration will will have a wider power curve and unusually also a high peak. Big changes to 1 part like the cam tend to make a poor result.

My cams are 246/250 @.050, and it both idles and pulls to 9k....high flow, high velocity ports with large nonrestricting ITBs. Everything needs to match for the best result.

 

I should added this piece....

Modifying means 2nd guessing the factory team. They made a lot of choices for a lot of reasons and a whole lot of things interact...so most modified cars have issues of one sort or another.

Also, all modifications are not created equal. I've seen (and at tines done ) some pretty poor work that could not possibly ever work correctly. Put these 2 together and you have a horrible car and happens way more often than good results.

I'm all for well done modifications but it needs some planning.

 

yeah I landed at the ‘sport’ cams Cat Cams in Belgium make which are some 247 @ .050 with .420 lift or thereabouts. Also added a slightly larger intake valve with a nailhead profile which showed decent flow gains at low lift and just a bit at above .300. That engine made 274bhp at the wheels (just under 3.4L), dynojet.

 

Sounds excellent!

Carbs or ????

Edit....did you need to do anything for the lift?

 

The rather low HP gain with the mods discussed again reinforces to me that the cost per HP is much too high for such mods on these cars for street use. When you also consider the drivability issues with the idle/low end range it just seems far too much cash/trouble for the result. I realize that the concern expressed in this thread is for an original-looking engine which, of course, rules out a supercharger though if that concern is tied to resale, the SC can be removed and the engine returned to stock with no visible changes. An 80-100HP increase (maybe much more according to some posts) would require no other component changes/mods and it doesn't sacrifice low/mid power to make high end power or have an adverse affect on idle/low speed operation.

Out in the real world, 99% of people looking at your car/engine will not know (or care) that a supercharger wasn't 'stock.'

OTOH, if concours events are your thing, I suspect the judges would subtract a point or two for a supercharger!

 

I've had 2 different superchargers on my 308.

The first made a best of 301hp at the wheels on a dynojet which I'd just over a 100hp gain at the crank. I use an Eaton roots type blower so boost from idle to recline but 10psi was the absolute limit and the air was pretty hot. Anyway, 5-6 psi at isle, 10 at recline gave about 190ftlbs torque at 1500rpm, so more than stock peak torque at idle. It cost me about $3-4k in parts to build all in with the efi and direct fire ignition stuff. Everything was bolt on. A lot of build time hours..50 maybe?

The blower whine was quite pronounced which I didn't love but other than that it was nice. Somewhere I have a video from the dyno, I'll look for it tonight so you can hear the whine.

The 928 kit is a centrifugal blower which should whine less, but little to no low-end boost, boost curve more like a turbo.

Compression, porting, cams, efi is probably $10k in parts give or take and will hit the same hp. Different engine sound, different driving feel from stock or boosted.

It all comes down to personal preferences and priorities.....that's why it's called customizing

 

A question for those with the knowledge and experience that I lack: Is it possible to get 300hp from a carbed 308 without appreciable loss of drivability? I can remember when 100hp/liter and 10lb/hp was considered pretty impressive.

 

"Compression, porting, cams, efi is probably $10k in parts give or take and will hit the same hp."

A hundred additional HP with cam/compression/fueling is, in my experience, not obtainable on a conventional 3 litre engine without totally destroying the low/mid range power and making the engine a giant PITA to drive on the street. HOWEVER, although I have a lot of professional experience with such mods, I have none on a Ferrari engine so I can't argue with someone who has. But it seems contrary to the laws of physics! OTOH, I barely passed physics...

 

Yes. 100hp/l is a very realistic goal and there are probably a couple dozen if not more out there. If you are talking crank hp, harder for wheel hp but still possible with more money. In the cost is no object world 150+/l is doable but the carbs have to go at this point.

 

I post the video of mine Idling and driving...its right in the 150-160hp/l range. EFI is the only way to tame this kind of setup.

Years ago I worked with a guy who did webers on his 328, mild build he got the 320ish hp he was after. More gets harder with weber but I've seen a few floating around.

These are all very doable numbers but as I said the parts need to be matched. To your point, it is easier with boost for sure.

 

Missed this part, you NEED to flow the heads or you end up needing P6 like cams and not drivable with weber. 10% flow bump is easy, 20% reasonable....then there is the nonsense I did to gain 60%

On street engine I like to be in the 240-250 deg @ .050 range with the cams, then set the heads to flow enough to make that work at the target hp. It's not a real rule but it usually seems to work out well.

Setting the flow also means intake and exhaust systems matched which can add a lot of work or cost if you're paying instead of doing. I think I spent nearly $3k on bent tubing to make my headers because they needed to be the size/design they needed to be.

 

I get and fully agree with it being difficult to out-engineer Ferrari to improve performance (outside of supercharger or turbo) in the general case, but given that the injected 2-valve version of the 308 engine was so weak because of the need to hit emissions back in the day, is there no easy way now to modify that engine to bring it up to the performance of the carbed 2-valve 308 version?

I think I recall the compression ratio being lowered around that time, and even more so for US versions, so that may be a factor that limits performance.