I would appreciate feedback fom anyone who has fitted these cams. Is there a peformance benefit right through the rev range as claimed? Thanks
I would stay away from most internal engine performance modifications. A Dino engine is already taxed as far as making a good street engine with decent performance. I have no experience with these particular camshafts but with modern gasoline of such low quality that you will never have a car that runs and performs as well as the factory set up.
I think there would be some disagreement on that - it certainly has not been my experience. The Superformance guys are pretty easy to talk to - would be worth a phone call. See if they have before and after dyno sheets. If they are claiming across the band increases the cams probably focus on higher lift with about the same timing -- It's all about airflow. With the some stories of stock 246 camshaft problems, if these are new billet pieces there may even be a reliability improvement. I'd at least ask around as you are doing. Good luck and have fun.
We installed their high compression pistons without a problem on my car. We did not fit their cams. My car makes about 180 RWHP, not a startling improvement, but a nice boost to about 205 HP at the crank vs. 175 stock HP on the US car. we also added the Stebro exhaust, which may have helped a little too, and of course all the pumps and other emissions stuff is off. It runs great on 91-93 octane. Incidentally, I've now switched out my Stebro exhaust for something a little subtler, we'll see if that adds or subtracts HP when I dyno it in August. Anyone want a 2 yr old stebro exhaust? PM me. DAve
Russ. I think the stock pistons were 9.5:1 and the new ones are 10.4:1. I am working completely from memory on this, so don't quote me. Got these because the pistons we wanted (Stock compression) were not in stock and Mike at superformance didn't want to make me wait. I've always found the guys there to be helpful and well informed about what they sell. Dave
When the car was new and we had it in the UK, we were instructed to always run it on "5-star" petrol, which I think was about 101 octane (usual caveats about all the confusingly different octane ratings). Today, it runs fine on 93, but I never have tried anything lower. Has there ever been a discussion here of the possible deleterious effects of unleaded fuel on the valve seats? We fitted a Stebro about 4 years ago. Nothing subtle about it! I think it does help make more power, but only at the upper end of the rev range, which I limit to about 6250 these days. Did you get an Ansa, Dave? I'd be interested to hear how it worked out. Long trips can get pretty tiring with the Stebro. (Though as expensive as it was, I'd hate to get rid of it. Since it's stainless, it'll probably last a long time...)
Thanks for the feedback so far. I am a bit sceptical about the cams as there is no Dyno data. Unless there are several people out there who have been impressed with the product in practice I shall steer clear. I think the cam wear problems are more to do with lubrication than errors in cam profile. Obviously decent High Comp forged pistons with modern thin rings will be an improvement If I really wanted to go to town I would fit lighter valves from G&S (same diameter heads for road use), light cam buckets with the small diameter shims, titanium spring collars, and get some new cams designed by Piper (or one of the other good outfits) to utilise the potential from the lighter valve train and get them to specify the correct modern springs.
Only using high compression ratio pistons is not the best idea. HC pistons alone would result in too high internal and crank pressures, would create difficulties starting the engine and generally stress all moving parts. They would however yield around 8bhp but compression ratio unit added. The best thing would be to combine HC pistons with bigger overlap and extended duration camshafts thus reducing overall dynamic compression ration, stressing your engine less and yielding far higher output. FYI the stock 246 engine will never deliver more than 175bhp at the crank no matter what.
Good idea. I think in most cases dyno data is important, especially with camshafts where there is a 'dialing in' process. I think higher compression pistons can somewhat be bought empirically, as long as possible detonation is addressed. the effect on low mid range can be quite remarkable according to nearly everyone. I also saw where Superformance offers 42 and 44 DCNFs as performance upgrades - how interesting!
I just spent a couple minutes going over my original engine rebuild invoice. cams went out to be re-ground. I don't know if we changed profile or just cleaned them up. I have to respectfully disagree with the piston comment. I now have about 7,000 miles on my engine with the higher compression pistons without incident. The last time at the dyno, everyone was surprised by how much HP my car made, but all agreed that the pistons, along with all the carb,exhaust and tuning work was what was making the extra HP. I'm going to chat with my mechanic this week and see if he recalls any adjustments we might have made to the cams, but I don't think we did. We did switch the 6 lobe US distributor out for a three lobe Euro one. I've never seen a dyno on a stock Dino (US or Euro) I'd love to see what HP they make, or made in the 70's as opposed to what Ferrari told us they made. dave
Well, as a published baseline, R&T May 1972 Road test lists: Compression ratio: 9:1 bhp est 175 @7000 torque est 160@5500 Autosport quotes 195 hp in May 1971 R&T Feb 74 quotes: 9:1 196 hp@7600 166 ft-lbs @5500 These seem to be the most often quoted above. And one crazy - July 71 MT quotes 225@7600 with 192 ft-lbs@5500 I am no expert, but I doubt it. The first pic is what I think is one of Dave's REAR WHEEL dynos in my collection;the second is a Carobu ENGINE dyno of a stock 246, stock cams & carbs except with 10:1 pistons. This seems to corraborate nicely the effect of these pistons as related by Dave. best to all Image Unavailable, Please Login Image Unavailable, Please Login
Yup,, Mine's on the left. Nice comparison, and yes they do match up pretty nicely. hmmm..... I wonder what my next dyno will look like? I'll post it here, eventually. DM
Are there any newer experiences with the fast road camshafts? As far as I know they are produced by catcams, with higher lift but more or less original timing. would be interesting how they are todrive. thanks in advance!
This thread is back from the grave! I have experience with these cams. The fast road camshafts require higher compression, at least 10:1, but they are indeed very street friendly. The have higher lift and more duration, about 247 degrees @ .050 if I remember right, but with a nice aggressive opening ramp rate. I have also learned you can safely go to around 11:1 compression with these as the hemispherical chamber is just not very efficient, and dynamically these heads just do not flow a lot of air compared to the 4v counterparts. Carburetors will require different jetting and likely a larger choke size. I've noticed a couple of different camshaft designs with Dino's. Some early Dino's have some .360 lift and a pretty racey 252 duration @ .050 while later Dino's use the same cams the 76-77 308s use, which is about .350 lift and 233 duration @ .050. The early Dino cam is also said to be seen on some, but not all, Daytona engines. The 252 duration @ .050 definitely needs more than stock compression to runs its best but Ferrari threw it in there anyway and they seem to run just fine.
