cadmaster

Now that I have read the whole conversation, I have not seen the "range" on where a "stock idle" would stop to where a mild lump would start and where a heavy lump starts. I see several results for the math as a negtive number and this means good idle and pass the sniffer test, right??? The three cams have the different postive numbers and the range from 5 to11. Now you all agree the 5 will be better that the 11 but, would these numbers fall in the "no lump" range or possability in the "mild lump" range.

02SS0384

iTrader: (1)

While I am far from a expert on this subject, I would hardly call an ASA a "mild lump" cam. I knew someone with an ASA in a 00' SS and it sounded mean. If I had to guess I would say a "mild lump" cam would fall in the low negative numbers.

blkZ28spt

I would agree with that. The ASA cam is FAR from mild. The "mild lump" would have to start in the lower negatives. You don't have to get too many degrees above zero before things get pretty roudy either. My cam checks in at 13.5* overlap and it idles (espceically untuned through my exhaust) pretty wicked. Also, more than overlap determines lope. Somebody did already state this, but Id like to say it again anywya. One of the things is the intake vs duration split. A cam that has a longer exhuast duration will be more choppy than a single pattern or one with a smaller split.

cadmaster

HUMMM interesting.........

After reading this I went and got the cam card that I am installing for a customer,( Car is stock except for a set of LPE heads and LTH and now this cam.) I will be doing the software work afterwards and it will be interesting the outcome on the predition of the cam chosen. It is the GM LS1 hotcam 525/525 218/227 112 and after doing the math I came up with -1.5 Since you all agree that a low negtive number will creat a mild lump. When I complete the work (also reworking the trans to handel estimated 500RWHP)I will post the results of the "Math" vs reality

tim99ws6

iTrader: (31)

I know this may be a little off topic, but here's my dilemma....

I am installing a TSP 233/239 in my Stock C.i. 346.....

Overlap-12*
split-6*


Will this "lope" harder/softer, or indifferent than the current cam setup in my father's Big Block? Its a 468c.i.

Overlap-19*
split-6*


What I'm wondering is does C.i. affect "lope" as well.....I mean, wouldn't it have to? I came up with the 19* of overlap on my father's cam using the same calculation I used for overlap on my cam(I+E, /4, -LSA, x2)


Do all the same rules apply? I say there's no way they could....can someone elaborate a little on this for me??

blkZ28spt

Now, is this a stock LS1 with LPE heads and longtube headers, into which you will be installing a hotcam?? The hotcam lopes pretty well, very well for a smaller cam. That huge intake vs exhasut split helps I am sure. Also, BTW, how do you expect 500 rwhp? I hope that is after more mods than what you listed.........like some nitrous maybe, lol.

greekss

alot of nitrous i hope....

cadmaster

My Bag!!

The bottom end is the only thing stock. It has more goodies, (that are not base engine mechanical, what I met “stock” in the early post, I was refering to the engine internals) and going to have more goodie in the future but since I pulled the engine to repair a massive oil consumption problem (got to love the UAW for the high dollar there people get but the quality of work is crap!!!! 4 pistons had all the gaps lined up). He wanted me to go through it to so when more parts are added on to increase HP the trans will hold it. I finished the transmission yesterday and it will be rock solid to 500RWHP after that ........................AXLE problems?????????

greekss

cool but a H/C esp with the hotcam will make a little over 400 rwhp.... so u will be spraying to get 500rwhp.... no way r u gonna get 500rwhp N/A with stock C.I.

SSick

in my garage is an F10 it's gunna have a stock idle? 228 + 228 /4 - 114 x2 = 0 overlap?

who else has an F10 on 114?

blkZ28spt

Stock idle? Um, no. The stock cams are far from zero overlap.

98Raptor

98 stock overlap is -35.5

SSick

HOLY *****!

BAIN

iTrader: (5)

Ok I'm cofused I just installed a 244/250 .615/.615 116+4 in my car and it sounds like a TR220 or 224 I thought the overlap was supposed to be around 19 or so. What the hell happened

98Raptor

What is your idle at?

tim99ws6

iTrader: (31)

Overlap should be 11(if you include your +4)
and split is 6...

Sounds like you're either idling really high, or you got a lot of timing in the car...either of these true? It should idle VERY similiar to a TSP 233/239

BAIN

iTrader: (5)

900-950. with 30* of timing.

Brnasi

I have been reading this thread with great interest - I just built a stroker motor that is 526 ci - my cam "number" is 74 - but the engine does not lope at all.Idles at a grand, but little lope. My last motor with 454 ci and a cam that calculates (using the above calc) to a 66 and loped like a pro stocker, so there has to be a relashionship between cubic inches and the lope. I first put in a cam that was a 70 - and it sounded like a UPS truck. New cam is a 74, better but not where I want it. Any thoughts or guidelines on how to make my stroker sound like my "little" motor did for the car cruises? BTW - these are both solid roller cams ground on a 108 LC and just shy of .700 lift. Do I need a new cam with huge overlap number (what number???) or can I roughen mine up somehow?

(I'm at 286 deg duration @ .050)...

Asmodeus

lower the idle for more lope. even with a lot of overlap you can get rid of lope with a higher idle. You'll create more exhaust velocity to pull the intake charge out of the cylinder causing less of the "choking onit's own exhaust" as Eric put it. exact opposite effect with lowering the idle. you'll have even less exhaust scavenging.

Brnasi

Thanks, I tried that today, at 900 RPM it just dies. I am thinking it may be partially the effect of the idle speed on the sound - a bad (good) lope (gallop) at 1200 RPM sounds much different than one at 900-1000 RPM (Loaded). At 1200 RPM on the new motor it's pretty smooth.

Maybe the exhaust is too small in diameter now (3.5) or the ratio of over lap to cubes isn't there...My other big block with a mild hyd lopes better than this. It also has flowmasters on it, vs my Dynomax's on the stroker motor - so the stroker is actually pretty quiet.