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I agree that overlap is the elephant in the room when it comes to driveability as it will cause misfires at idle and low load steady state conditions, but I disagree when you say -
Originally Posted by Martin Smallwood
Overlap and overlap alone is the deciding factor in how a cam drives in regards to drivability. Not exhaust duration.
Part throttle efficiency, emissions, and torque production is dramatically affected by valve events - and you will sometimes want radically different events at part throttle than you would ever want to see at WOT. If this wasn't the case VVT would be irrelevant. Hell - throw your cam in there 4* advanced vs 4* retarded and you'll have a very different driving experience with the same overlap.
These will idle the same yes, but the same driveability? Maybe we have a different interpretation of that term.
It would be nice if there was a concrete way to share part throttle driving characteristics other than "it drives like stock" or "it surges a little" because everyone is going to have a different tolerance and definition of success when it comes to how a car drives.
ddnspider- Man, you gotta lighten up. All they did here was to try to build a better mousetrap by improving on a known good mousetrap, even if it's old tech. Are there more up-to-date cams out there? Yup! The thing here is, the GM Hot Cam is a known, and good for its age, quantity. This was an exercise in seeing how good it could be by updating an aspect or two of it. If you don't care about the outcome, move on. There are those here who are interested to see what could come of it. Maybe you don't agree with the thinking or methods involved. Fine. I have no problem with it, and doubt many others do either. Info is info. Better to know than not to.
Haha I almost put better mousetrap in my post. A better analogy was that they created a better Microsoft Zune when everyone is buying Ipods. Obviously you missed the important point in my post. If his intent was to specifically make is scientific, with changing only lift and lobe design, then fine. Make a thread that specifies info like timing/rpm range/intake temp's/etc./etc. All I see in the posts is vague random info and the customers testimony is gospel with little data other than 2 random dyno graphs to back it up. That's my issue. You don't need a custom cam to have it drive just as good and make more power. There's plenty of off the shelf stuff that will do it.
You want the info call new era. There is a thread on it and the customer said all that not me. I am merely relaying whst was said.
You are reading what isnt written nor is any of it vague. Something appears to have rubbed you wrong and you are reading with a bias.
Ive said about 5 or 9 times it did exactly what i wanted. The customer input is all after the fact and needed feedback on before and after that most tests you dont get.
Little data? Cmon. Its a dyno graph. Its literally what everyone asks for.
it would be nice if there was a concrete way to share part throttle driving characteristics other than "it drives like stock" or "it surges a little" because everyone is going to have a different tolerance and definition of success when it comes to how a car drives.
The only way is to have a log of driving before and after focusing on map, engine load, poss calc torque, spark, and fuel trims/O2 voltage/inj duty cycle and ms....its really only noticeable with lower numerical gears (or stock) or maybe a stock stall that keeps locking and unlocking in cruise/steady state. Youd also maybe notice it down low off clutch engagement with little pedal or going up an incline.
in the industry i am always surprised at what either people dont notice, get used to on their own, or are told is normal and accept.
You want the info call new era. There is a thread on it and the customer said all that not me. I am merely relaying whst was said.
You are reading what isnt written nor is any of it vague. Something appears to have rubbed you wrong and you are reading with a bias.
Ive said about 5 or 9 times it did exactly what i wanted. The customer input is all after the fact and needed feedback on before and after that most tests you dont get.
Little data? Cmon. Its a dyno graph. Its literally what everyone asks for.
Whatever you say, I didn't realize that 1 Dyno graph with marginal info at best was the whole story. Hell, before that dude made his thread and you popped in there I didn't even know ws6store made cams, not that I would buy 1 after this hilariousness. I've said my peace, glws.
At least youve said your peace. If you read any if these threads concerning that cam and build youd find all the info that is given in any other dyno sheet/build. What makes this one any diff that has peed in your post toasties is not really clear. You dont grasp the concept of why it was done i guess. We dont build alot, but when there is a trend to something we believe we can improve on, we will try. Maybe youve missed the other 30 posts about people recommending us for cams or even me weighing in on them. At least now you know and can avoid if you want.
At least youve said your peace. If you read any if these threads concerning that cam and build youd find all the info that is given in any other dyno sheet/build. What makes this one any diff that has peed in your post toasties is not really clear. You dont grasp the concept of why it was done i guess. We dont build alot, but when there is a trend to something we believe we can improve on, we will try. Maybe youve missed the other 30 posts about people recommending us for cams or even me weighing in on them. At least now you know and can avoid if you want.
I didn't miss anything, I just disagree with what you did and the point of it....just like you disagree with overlap is the main determining factor in how well a car drives....there we are, now we've come full circle back on track.
I must be in the wrong thread. I thought we were talking about TSP & changes in cam design philosophy. Much of this thread reads like a rake WS6 Store over the coals for fun thread.
I have a lot of respect for Martin Smallwood & his contributions. I also have a lot of respect for WS6 Store.
Overlap definitely affects idle quality. The 240/250 108 LSA cam in a 383 I used to have in my 72 vette had +29 degrees overlap . It drove fairly well all in all.
I must be in the wrong thread. I thought we were talking about TSP & changes in cam design philosophy. Much of this thread reads like a rake WS6 Store over the coals for fun thread.
I have a lot of respect for Martin Smallwood & his contributions. I also have a lot of respect for WS6 Store.
Overlap definitely affects idle quality. The 240/250 108 LSA cam in a 383 I used to have in my 72 vette had +29 degrees overlap . It drove fairly well all in all.
So I think TSP was called out by the OP in the beginning because of their shift in philosophy to what many others in the industry have been doing for a while... so again, I don't see that as much as progress, but more of a confirmation of an alternate cam theory born out of additional testing on TSP's part. So I applaud them for continuing to test and innovate for the LS platform and shifting their philosophy based on real-world test results.
But the tech around overlap and the like is very pertinent to choosing or designing a cam for a given combo. Hence my re-direct to at least bring it back on track.
The Hot Cam thing is really quite off-topic. I meant to come back and end that. Although, last night, it was kind of entertaining...
And the 72 Vette had a single plane intake? You have to cam those completely differently. And typically you need a lot more overlap with them. So that's not exactly apples-to-apples unless we are looking at MAST, Victor, or CID intakes.
So I think TSP was called out by the OP in the beginning because of their shift in philosophy to what many others in the industry have been doing for a while... so again, I don't see that as much as progress, but more of a confirmation of an alternate cam theory born out of additional testing on TSP's part. So I applaud them for continuing to test and innovate for the LS platform and shifting their philosophy based on real-world test results.
But the tech around overlap and the like is very pertinent to choosing or designing a cam for a given combo. Hence my re-direct to at least bring it back on track.
The Hot Cam thing is really quite off-topic. I meant to come back and end that. Although, last night, it was kind of entertaining...
And the 72 Vette had a single plane intake? You have to cam those completely differently. And typically you need a lot more overlap with them. So that's not exactly apples-to-apples unless we are looking at MAST, Victor, or CID intakes.
Not to stray too far regarding the 72 vette, actually Doug Herbert Performance built the engine back in 2007 specifically for my 72 vette. They lied about the cam specs when building the motor. The cam was supposed to be much milder. They put their pet mild lobe solid roller 240/250 cam in the 383 and Herbert slapped an Edelbrock Performer dual plane intake on it. Post mortem confirmed the cam was indeed a catalog mild solid roller. With a set of cheap hydraulic lifters. The mismatch pile self-destructed in 2000 miles. It's an entertaining horror story, I will share in detail one of these days. I think I still have the picture of the sticker left inside the timing cover...found it
Doug Herbert Performance's lack of attention to detail in 2007. This sticker was found inside the timing cover on disassembly of my 383 they built. The motor lasted 2,000 miles of easy break in driving.
I mentioned the nasty 29 degree overlap to show I agree with Martin's comments that overlap has massive impact on idle quality.
I'm glad TSP and the other vendors keep researching cam improvements. The new WS6 Store revised Hotcam is a novel idea and an example of on going testing and research. I have a friend that still talks about one day he might do a hot am for his Firehawk. Mostly due to the sound.
Solid Rollers drive better than their hydraulic cammed counterparts, which is one reason I like the LLR in an NA car - sort of all the benefits of a SR while being close to hyd is set and forget it for a while mentality.
Also, their .006-.050 duration numbers drop from 50-55 for a hyd to like 25-28... so at .006 they are much milder. Also, as they heat up, the durations "shrink" usually 6-10 degrees based on lash.
But 29 degrees is a lot in a 383 with a dual plane.
05-25-2017, 12:35 PM
I almost put better mousetrap in my post. A better analogy was that they created a better Microsoft Zune when everyone is buying Ipods. Obviously you missed the important point in my post. If his intent was to specifically make is scientific, with changing only lift and lobe design, then fine. Make a thread that specifies info like timing/rpm range/intake temp's/etc./etc. All I see in the posts is vague random info and the customers testimony is gospel with little data other than 2 random dyno graphs to back it up. That's my issue. You don't need a custom cam to have it drive just as good and make more power. There's plenty of off the shelf stuff that will do it. 
