inline6 Posted September 2, 2009 Share Posted September 2, 2009 About to pay a bunch for a cam from Kinetic Sunbelt (in GA). They came back to me with specs which are below. I've run a 490/290 in my 510 years ago (daily driver in college) which I liked... I've read some posts and tried to decipher what cam is really too radical. My car has an F-54 L-28 with flat tops, about 10 to 1 compression with E88 head (1 mm bigger intake valves). Switching from SU's with SM needles to a set of tripple 44phh Mikunis when I do the cam upgrade. So, is this cam going to be too radical? Can I still drive it to and from the track? It pretty much just sees autocross and track duty these days, but I don't trailer it. Intake Seat duration 320 degrees .050" duration 290 degrees Valve lift with zero lash .565" Hot valve lash .015" Net valve lift .550" Exhaust Seat duration 315 degrees .050" duration 274.8 degrees Valve lift with zero lash = .565" Hot lash = .015" Net valve lift =.550" Quote Link to comment Share on other sites More sharing options...
jc052685 Posted September 2, 2009 Share Posted September 2, 2009 define streetable...... Quote Link to comment Share on other sites More sharing options...
inline6 Posted September 2, 2009 Author Share Posted September 2, 2009 I don't want to have to drive it like a race car to keep it moving on the road, in traffic, at stop lights. I drive to and from the track plus put about 1000 street miles on it a year. I realize this is a question with what is likely to be very subjective answers... Hoping to get some responses from people that have something similar and their thoughts on driving on public roads. Quote Link to comment Share on other sites More sharing options...
rucus01 Posted September 2, 2009 Share Posted September 2, 2009 About to pay a bunch for a cam from Kinetic Sunbelt (in GA). They came back to me with specs which are below. I've run a 490/290 in my 510 years ago (daily driver in college) which I liked... I've read some posts and tried to decipher what cam is really too radical. My car has an F-54 L-28 with flat tops, about 10 to 1 compression with E88 head (1 mm bigger intake valves). Switching from SU's with SM needles to a set of tripple 44phh Mikunis when I do the cam upgrade. So, is this cam going to be too radical? Can I still drive it to and from the track? It pretty much just sees autocross and track duty these days, but I don't trailer it. Intake Seat duration 320 degrees .050" duration 290 degrees Valve lift with zero lash .565" Hot valve lash .015" Net valve lift .550" Exhaust Seat duration 315 degrees .050" duration 274.8 degrees Valve lift with zero lash = .565" Hot lash = .015" Net valve lift =.550" That cam is insane and may not even start that motor. Quote Link to comment Share on other sites More sharing options...
MAG58 Posted September 2, 2009 Share Posted September 2, 2009 Well expect to lose all practical bottom end and have a real cool lope. Is it streetable, most likely not. Would I put it on the street? Most likely. Quote Link to comment Share on other sites More sharing options...
Scott_M67 Posted September 2, 2009 Share Posted September 2, 2009 That thing is huge, not sure it would even lope with 290@.050" duration, it certainly won't make any low end torque which you may want with autocrossing. I would think a 280 or 290 with something like 240-245 degrees at .050" would be much more driveable and responsive, just my 2 cents. Quote Link to comment Share on other sites More sharing options...
MONZTER Posted September 2, 2009 Share Posted September 2, 2009 With that low compression I would stay 270/280 max or loose your bottom end Quote Link to comment Share on other sites More sharing options...
PanzerAce Posted September 2, 2009 Share Posted September 2, 2009 That cam is insane and may not even start that motor. Maybe not on SUs, but he said he's switching to triple mikuni 44. *my* experience with my cam/ carb setup (rebello 63D + triple mikuni 44s), is that the only problem starting is filling the fuel bowls (still running the mech fuel pump). Personally, I think it'll be fine. Yes, you'll lose at the bottom end, but hey, that just gives you an excuse to let the engine scream some more Though you are going to have to tune your carbs *really* well, since as Mag pointed out, it's going to lope, alot. Also, the cam + carb setup means that your idle is going to change a fair bit depending just on the ambient air temp and the engine temp. And Monzter, when did 10:1CR become low? Quote Link to comment Share on other sites More sharing options...
Scott_M67 Posted September 2, 2009 Share Posted September 2, 2009 10:1 is pretty low once you figure out that the resulting dynamic compression with that cam will be something in the 6:1 range. Triples or doubles doesn't change that fact, that cam would do much better with 12:1 or 13:1 with those duration numbers but then you'd be running race fuel, its an all out track cam. I wouldn't use anything with more than 240 @.050" with 10:1 compression. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted September 2, 2009 Administrators Share Posted September 2, 2009 10:1 is pretty low once you figure out that the resulting dynamic compression with that cam will be something in the 6:1 range. Triples or doubles doesn't change that fact, that cam would do much better with 12:1 or 13:1 with those duration numbers but then you'd be running race fuel, its an all out track cam. I wouldn't use anything with more than 240 @.050" with 10:1 compression. For a typical 2 valve aluminum head engine, that is correct. Keep in mind this for the L-6 which is quite a bit more detonation sensitive compared to other 2 valve aluminum head designs, and compression ratio is a key player in that! In my experience and what I've gleaned from others experience here is that generally, the L-6 will only tolerate 1.5-2 full points less static compression ratio for its detonation threshold at full maximum power producing ignition timing on premium pump gas, N/A or boosted! http://forums.hybridz.org/showthread.php?t=125186 There are a few exceptions that have been able to follow the typical static compression ratio and not rattle, blow head gaskets or bust pistons, but those are not the norm. Regarding dynamic compression, that figure really only applies at engine cranking speed and idle. Once the engine starts to rev with a radical race style cam, the engines BMEP actually becomes greater than if a milder cam was installed, (more torque is more BMEP), as it nears torque peak due to more efficient cylinder filling, i.e. dynamic compression “pressure†becomes greater, not less, (hence the grater torque figures), regardless of the “calculated†ratio. Again the calculate dynamic comp ratio only applies at engine speeds where ram charging is not taking affect. Granted, the wilder cam will offer more detonation resistance vs a milder cam due to other attributes dynamically taking place, but that attribute is small in comparison vs the added BMEP, so it's a compromise. HOTROD magazines have started yet another myth with calculated dynamic compression ratio being “the†detonation resistance factor, when they forgot to mention the added BMEP at elevated RPM’s. At any rate, with more aggressive cams, that 1.5-2.0 points less static C/R the L-6 will tolerate starts to drop to 1-1.5, etc. At some point, the cam just becomes to radical and the compromise in static C/R for the intended gasoline must be made. Back to the question at hand, as has been questioned already, ones definition of “streetable†is going to be different from another. This is really one of those subjects that is like the visual aesthetics of a particular car. It really lies in the eye of the beholder, or in this case, the seat of the driver. When giving advice for an ideal camshaft, I try to leave out my person perception as much as possible and only quote what qualities the cam would give the engine so the end user can discern based on his/her own taste if that is what they want or not. Some might prefer the most radical lopey peaky power band and call it street able, others may say only stock cams are street able. What others have said regarding the “attributes†of that spec, I agree with. Whether or not the original poster deems that as “street-able†is entirely up to him. Hope that helps, Paul Quote Link to comment Share on other sites More sharing options...
Tony D Posted September 2, 2009 Share Posted September 2, 2009 I'm probably not someone who should comment on what other people think might be streetable. I found a 2110cc VW Turbo with an extremely rough idle of 1800rpm and a power band that started at 4500 (with a 10# flywheel) to be extremely entertaining. Rapping out the engine to keep the plugs clean at stoplights was grand fun... My opinion is useless in this matter, yet I blather on incessantly just because... Quote Link to comment Share on other sites More sharing options...
Scott_M67 Posted September 2, 2009 Share Posted September 2, 2009 Thanks for taking the time to elaborate on the subject further Paul, and adding the point about the BMEP. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted September 2, 2009 Share Posted September 2, 2009 I'm probably not someone who should comment on what other people think might be streetable. I found a 2110cc VW Turbo with an extremely rough idle of 1800rpm and a power band that started at 4500 (with a 10# flywheel) to be extremely entertaining. Rapping out the engine to keep the plugs clean at stoplights was grand fun... My opinion is useless in this matter, yet I blather on incessantly just because... LOL, that's why I didn't say much either. Quote Link to comment Share on other sites More sharing options...
Tony D Posted September 3, 2009 Share Posted September 3, 2009 LOL, that's why I didn't say much either. "There are others here like you...you will find kinship!":twisted: Hi, My name is Tony, and I am a Camaholic...I have been stock cammed in my daily driver for 158 days now... Quote Link to comment Share on other sites More sharing options...
MAG58 Posted September 3, 2009 Share Posted September 3, 2009 "There are others here like you...you will find kinship!":twisted: Hi, My name is Tony, and I am a Camaholic...I have been stock cammed in my daily driver for 158 days now... Friends!!! Hi. I'm Bob. I summer DD a mini with a full race 312 duration cam and 1.6 rockers. Good company I see... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted September 3, 2009 Share Posted September 3, 2009 Look up the specs on Dan Baldwin's engine and cam. I think he might have the same cam, and he ran it on the street. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted September 3, 2009 Share Posted September 3, 2009 I remember an Evo8 I used to have sported a full race motor and I drove it every day. (Shop car and all, so I had an excuse... ). When they were newer cars in the USA and most ppl didn't know what they were, it was funny to watch people's faces ahead of you in the Taco Bell line when they hear the "rump rump rump" from the little import with the big spoiler. Dang, that thing would shake your chest at idle. I miss it. Even though everyone called it Satan on wheels for all the R&D issues I had to deal with. LOL. Quote Link to comment Share on other sites More sharing options...
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