Cam’s and drivability what’s the deal

I'll be as honest as I can, b/c I know these types of threads get a broad range of answers, and you never know if someone is sugarcoating. I have the mods listed in my sig, including a Trick Flow stg 1 cam and 24lb injectors, without a tune. My car idles a little rough at startup and will die for the first couple of minutes. Also, I occasionally will have to blip the throttle at stop lights to keep it running if I'm at a long light. I also get some bucking if I lug it down to 1500rpm or so. Other than that, it runs very well (WOT is awesome); better than I expected w/o a tune. All my problems are minor, and I am used to the way the car runs so it doesn't bother me but I plan on buying a self-tuner to smooth it all out.

i think lobe separation angle (lsa) is what wreaks havoc on the computers

Your best bet is talk to custom cam grinder like Ed C at FTI. I know in my situation, I needed a tune after the cam. My car was also a DD so I needed to have good drivability. But it almost seems that every car is different in how they response to cams. Some idle and drive fine, and others surge and die. Talk to a cam grinder and it would probably be a good idea to allot an extra $500 in case you need a tune or want to take a shot at self tuning with a Tweezer or similiar product.

I drove my car for a month and a half without a tune, every day +50 miles. It died a few times, but the idle was fine.

I had it tuned with a JMS chip wich gave me alot more horsepower.

I've got an F cam, 30 lb inj, no chip or computer tune, idles rock steady.

If it's a daily driver and you depend on it to get to work, etc., I personally wouldn't do a HCI without plans for a tune. But if it's a second car then you might as well do the HCI and see how your car responds

wide open throttle and cruising shouldn't be a problem its just when the car is not in gear and you will get a idle surge and sometimes stall. but i drove mine without a tune for months and it was fine, just got embarrassing when it would stall and then i would start it and rev the crap out of it, and then everyones looking at me like I'm trying to be cool or something.

ive got a 306 w/an ultradyne cam w/585 lift and a custom tune from superchips car starts perfect no idle issues or dying ever,just need to have it properly tuned and you will be fine,when you get a bunch of people start wrenchin on your **** w/o a clue thats when you get those kinda probs.....

chromeyllastang highlighted a point I would like to discuss. It seems as though it is imperative to get your car tuned to any cam that is wild in lift, duration or LSA.

This being said, is it possible to maintain a solid 700-900rpm idle with a cam that will make useful power to 7000rpm? specifically, I would want around 255* at .050, .540+ lift, and an LSA around the neighbourhood of 108-110*. Assuming this is properly tuned, will a steady idle be feasible? Tuning method of choice would be a tweecer

Georgia50 said:

So with the cam it should do ok until I can get a tune or tune it myself?

I’m going to get the trick flow kit that comes with the stage 1 cam, heads etc.

So I’m just tiring get all the info I can before I start.

Thanks for the help. :SNSign:

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Everybody has their opinion about why our cars don't like hot rod parts.

I have mine as well ... but ... It is backed up by a bit of experience over the years with my Stang and the findings of many other self tuners I have worked with.

Some say the pcm freaks out because of .................

small cam lsa
large cam overlap
larger maf
larger inj's
not enough vaccum at idle
and the list goes on and on and on

Each Stang and combo even though they may be very similar can have its own unique set of variables when it comes to the outcome of putting together a combo and how it effects drivability.

Don't let anybody tell you all will be ok just because they had no issues severe enough to require a tune.

You say you gonna go with the TFS combo kit. Over the past year or so, many others have done the same.

Some had no drivability issues and others could not tollerate the upgrade until a tune was put in place.

You really never can know about drivability until you put it together and see how it all turns out.

I got all that stuff on that list above and I'd be willing to bet my lsa is lower than most on this site.

My car drives like a little stock Stang except for cam lope and self tuning made that happen for me.

If I was you, I'd plan on a tune and if you don't need one or you find the drivability issues are not so bad you can't deal with them ... then you got lucky ... I guess you could say

Good luck with your plans

Grady

I agree.. the whole thing is that the car needs to be "Tuned" for the HCI change... any car!! befor computers the "tune" was done by the driver.. change the jets in the carb.. change the ign timing and the curve in the Dist, .. it was all do able by hands!! the computer ended that!! NOW you will have to do the same things.. but go thru the computer!! Count on it!! Or you will be pissed and embarrased when it idles like mess and stalls out all the time!! IF your asking the questions on HOW to tune.. Or is it necessary?? they YOU WILL NEED to have some one tune it!!

Keep the CC in the intake runners small.. the cam LSA needs to be 110-114 for the computers.. duration keep it at 224-230.. all this is for you car to be able to have agood time . In your town .. just go and sak the guys whts their ET at thr track, then back out their BS to getthe real times, you will see most are 13..12s and maybe an 11 sec car !! Now see what they have.. then put that up against the cost of their HCI .. and remember huge intake CC runners and huge duration numbers and tight LSA all equal big power.. or a turd if not tuned right!! cool??
Just me.............................

Thumper

thumper460 said:

I agree.. the whole thing is that the car needs to be "Tuned" for the HCI change... any car!! befor computers the "tune" was done by the driver.. change the jets in the carb.. change the ign timing and the curve in the Dist, .. it was all do able by hands!! the computer ended that!! NOW you will have to do the same things.. but go thru the computer!! Count on it!! Or you will be pissed and embarrased when it idles like mess and stalls out all the time!! IF your asking the questions on HOW to tune.. Or is it necessary?? they YOU WILL NEED to have some one tune it!!

Keep the CC in the intake runners small.. the cam LSA needs to be 110-114 for the computers.. duration keep it at 224-230.. all this is for you car to be able to have agood time . In your town .. just go and sak the guys whts their ET at thr track, then back out their BS to getthe real times, you will see most are 13..12s and maybe an 11 sec car !! Now see what they have.. then put that up against the cost of their HCI .. and remember huge intake CC runners and huge duration numbers and tight LSA all equal big power.. or a turd if not tuned right!! cool??
Just me.............................

Thumper

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Thumper, do you think you could answer my query? I'm quite curious. And if it is not possible, what do you think the upper limits are (I want my car to be able to rev AND make power). Nevermind my signature, I will be running a far different combo (I don't really even have one now...sigh)

Therian said:

Thumper, do you think you could answer my query? I'm quite curious. And if it is not possible, what do you think the upper limits are (I want my car to be able to rev AND make power). Nevermind my signature, I will be running a far different combo (I don't really even have one now...sigh)

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I ain't Thumper

BUT

I've ripped apart countless carbs for jet changes and recurved many a dizzy back in the days of my youth

He has hit the nail squarely on the head with the tune and how it has changed from the mechanical method to the laptop method.


I'll paste from my above post my answer to your inquiry

My car drives like a little stock Stang except for cam lope and self tuning made that happen for me.

Hey .......... It ain't just about me ...........

Many others have done the same as well

Grady

final5-0 said:

I ain't Thumper

BUT

I've ripped apart countless carbs for jet changes and recurved many a dizzy back in the days of my youth

He has hit the nail squarely on the head with the tune and how it has changed from the mechanical method to the laptop method.


I'll paste from my above post my answer to your inquiry

My car drives like a little stock Stang except for cam lope and self tuning made that happen for me.



Hey .......... It ain't just about me ...........

Many others have done the same as well

Grady

Click to expand...

Thanks Grady, I def. appreciate your input. I guess Ed didn't give you the stats on your cam...I'm just wondering what the upper limits are that I can push on a cam before even a tune can't fix the idle

final5-0 said:

Some say the pcm freaks out because of .................

small cam lsa
large cam overlap
larger maf
larger inj's
not enough vaccum at idle

Grady

Click to expand...

I completely agree with that. When I first went cam shopping, many people told me our cars don't like "big" cams. But I have seen many people with huge lift (I have more lift on my cam than Trick Flow recomends with a stock shortblock) and/or large duration and the car runs fine, most likely because those factors Grady mentioned above are "in check"

Anyone see the 5.0 Mustang article a few weeks back about the silver NMRA pure street car? That guy had a 94/95 EEC computer with no chip or tune and was revving his car to 7000rpm! I know it was a pure drag car, but hey, the cars idling fine enough for him to get around the pits (I know this because I saw him drive it around the pits).

Therian said:

chromeyllastang highlighted a point I would like to discuss. It seems as though it is imperative to get your car tuned to any cam that is wild in lift, duration or LSA.

This being said, is it possible to maintain a solid 700-900rpm idle with a cam that will make useful power to 7000rpm? specifically, I would want around 255* at .050, .540+ lift, and an LSA around the neighbourhood of 108-110*. Assuming this is properly tuned, will a steady idle be feasible? Tuning method of choice would be a tweecer

Click to expand...

I would say anything is possible with a proper tune, but without a tune, a 108 LSA cam is going to be rough idle and dying car city, it would be very frustrating.

Therian said:

Thanks Grady, I def. appreciate your input. I guess Ed didn't give you the stats on your cam...I'm just wondering what the upper limits are that I can push on a cam before even a tune can't fix the idle

Click to expand...

I think I now understand better what you are talking about

I do have my cam specs btw ..............

however

Nobody who has a cam from custom folk like Ed, Jay, Buddy or others is gonna share their specs out of respect for keeping their cam builders trade secrets ... secret

I won't get into all that cam spec stuff as I don't claim to know anything about it other than general, basic knowledge.

Ed spent a good bit of time with me on several phone calls before I made up my mind specifically about my final goals.

When he found out about my age and my past with small block Fords, he had to remind me on more than one occasion to not think ... old school ... as he called it.

Basically ... he said because of peeps moving away from flat tappit cams and OEM heads, the cam specs did not have to be as radical as they were in the past for typical na street combos.

I only said that stuff to you because I really do believe ... if I could do it all over again ... I could go a good bit hotter with the cam specs

AND ALSO STILL ..............

I could make the car behave pretty well on the street

The pcm can be optimized to the combo ..............

That is a fact NOT an opinion OR hearsay

I have learned a thing or two about how everything works together from the pcm's perspective.

I just put that knowledge to use with my self tuning efforts and know I am not being unrealistic when I say things along those lines.

Again ... it is not about just me

Many other self tuners have used their laptops as well to make the pcm have values that more closely match the conditions that have changed from their upgraded hot rod parts.

Heck ... Pro Tuners use this known fact to make a living

Bottom Line here is this ...................

You don't have to put up with drivability issues on your street car.

btw ... I did read over your above post closely and you will not be able to idle at 700 rpm.

Even more so if you step up the cam specs like you are talking about.

The idle clip in my sig was about 850 rpm IIRC.

I CAN idle at 700 rpm but ...........
it lopes like a mofo
and
peeps stare at you at stop lights
and
things are a bit unstable to suit me

Hope this helped you some how or some way

I'm done now

Grady

Grady, you addressed my question perfectly. the objectivity is refreshing too