Kory-88Iroc 350 tpi

iTrader: (1)

I've got one for you.
I'm building a 94 s10 that I plan on driving daily when it's done.
So far I have a 05 lq4 and a ls t56. I plan on putting an 8.8 explorer rear end in the truck. I will be building a set of 1 3/4" lt headers and probably a 2 1/2" dual exhaust. the truck should weigh about 3200 lbs when done and will probably have either a 3:55 or 3:73 rear gear. If I Keep the stock lq4 heads (317) the compression should be 9.4 to1 I am planning on putting an ls6 intake on it but could keep the stock one for more torque if it breaths well enough to rev to 6200-6400. I know the danger of over camming a motor. I had 7 different grinds in my lt1 before the current combo. for the truck I would like driveability and decent mileage most of all (my camaro is fast but only gets 16mpg) but would like to trap 117mph if possible.
What do you think?
btw I could always build a small rear mount turbo setup if I absolutely need more top end power. I'd prefer this to a too large cam. in other words I believe we are on the same page.
Thanks for you time and knowledge.
Kory

Atilla the Fun

You instantly succeeded in getting me interested in your Camaro. I've done the V8 S-10 thing, and I tried installing my LQ4 in it. It can't sit as low or as far rearward as the SBC, so out it came.
I drove that 355 in my S-10 for all of summer 2009. I tried a spool, and slapper bars, and drag radials in a 275/60R15 size, but I never did get the thing to hook up. And that's with a lot less grunt than you're about to have.
Still, If you're wanting 6400 rpm, forget the truck intake.
Getting your heads shaved 0.030" will get you a much better 9.9:1, which is still rather sad.
I have a cam in mind. I have a link, but the info on the other end is no longer there. I guess this cam wasn't selling well enough. So I'll have to tell you about it.
It was tested in an LS2 with an automatic. Stock, the results were 315 rwtq at 4000-4200, and 300 rwhp at 6000-6200. Then with this cam, 1.75" long tubes, and a tune, it jumped to 355 rwtq at 3600, 360 rwtq at 4500, 355 rwhp at 5400-5850, and still over 300 rwtq up at 6100. At 6500, it gave about 335 rwhp and 270 rwtq.
Correcting from automatic to manual, that's 400 rwhp at 5400-5850.
Too tame for you? At least it'll pass a smog test and give great mpg.
Now, why is the Camaro only doing 16 mpg?

Kory-88Iroc 350 tpi

iTrader: (1)

In the camaro I have a 355 lt1 with Advanced induction 200cc cnc heads,ported intake, and one of their midlevel streetable cams I don't have all the specs because they didn't include a cam card but what I know is 228/234 .600/.600 I built the bottom end a little over a year ago. it has 6" compstar rods,mahle pistons, 4 bolt studded bottem end with about 11.8to1 compression. t56, 8.8 rear built by me with 410to1 gears 1 3/4" lt headers built by me, free flowing y pipe and 4" exhaust. it weighs about 3500lbs. I don't know exactly why it gets only 16mpg. The tune seems to be dead on.I haven't taken it on any real highway trips yet. I don't know what it could ultimately do in an all highway situation, but mixed is a best of 16.
As far as the s10, would I be better off killing a little of the low end and running the 355 gear instead of the 373's to make it hook a little better? Did you ever try caltrac bars on your s10?
just noticed I have most of the car info in my sig, sorry for the redundancy.

Atilla the Fun

With a T56 having that 0.5:1 sixth, you have to choose your axle ratio according to what cruising rpm your cam wants. Choose cam first, then tire diameter, then axle ratio.
Until you take the Camaro on a road trip and get real mpg numbers, there's nothing to be done for it.
CalTracs and competetion Engineering Slide A Link are both just improvements on the slapper bar. They're street improvements. On the track, they're no better than properly set up slappers, which is what I grew up with.
I wasn't about to push the throttle on a V8 S-10 in the canyons with tall sticky tires, so I used the slappers I already had. And away from a traffic light, in a straight line, they are the equal of CalTracs.
Since you seem used to bad mpg, you could get the 3.55:1 axle for now, and just not use sixth gear until you get the rest of the combination more dialed in. On 275/60s, you'd be around 6600 through the traps in third gear.
It's already looking like a solid combination.

Guest

Attila, you've stated that Vizard's approach to lobe separation is a bit off, if I understood you correctly. Yet his cams seem to make good upper rpm torque, like the LS engines seem to. Am I missing something?

Atilla the Fun

For racing, that's great. But that's what Vizard does: race, NOT street. He treats LSA like a cause, when really it's an effect. LSA isn't a rule of thumb, contrary to Vizard's narrowly-focused thinking. It's a coincidental result of proper choosing of valve events. Exhaust opening is the first event in sequence, followed by exhaust closing, then intake opening, and intake closing is the last event.
That's for street cams, with little overlap, and with events at 0.050" lift. If you're talking radical race cams, then it's EO-IO-EC-IC.
You have 2 full strokes between intake closing and exhaust opening, but you have no strokes at all between exhausting and inducting, so that's why we should list exhaust first, not intake.
You need a proper understanding of what timing of what event affects what, and once you pick those right, you then use those to calculate what durations and lobe centers they happen to be.
Vizard may think his way is faster. If you're half hearted, it may be. But that doesn't make it good.

Guest

So how do we spec these? Most of us probably read all the cam selection articles in all the magazines, why don't they ever discuss doing it this way?

one92rs

iTrader: (5)

without the years of experience.. you dont. if you ask on the board it is all experiences. if you want a specked cam ask atilla. it is his life. do it now.

Atilla the Fun

Thanks for the backup, but it is a fair question.
Those articles are usually titled something like "Camshaft 101"
I prefer to think of cams as a 10 rung ladder, with the top 2 rungs having the warning sticker saying don't stand on them.
The first rung then, must be all the people who like their stock cams in their stock cars. Rung 2 has to be the really new newbs who just go with whatever their uncle suggests. The third rung would be those who open the cam catalogs, read the descriptions, and then choose. Rung 4 is the guys who really study every catalog and magazine article they can find. And when I say guys, I do mean guys. You could count on one hand the number of ladies on earth who have gotten to this level. Sad. Rung 5 is guys who apply what they learned on rung 4 to custom order several cams just to learn from their attempts.
Rung 6 is guys like Harver Crane, Scooter Brothers, and Billy Godbold. So rung 7 is guys like David Vizard, and most of the Engine Masters you've heard of. Guys like Joe Sherman and Ken Duttweiler.
Since I know you would ask, I'll pre-answer. I'd say I have one foot on rung 7.
So, how do you spec cams? You climb to where I'm at. One rung at a time.
Harvey Crane once told David Vizard that a 100 hp cam was impossible. Vizard took a typical 280 hp SBC 350, with a Crane shelf HF cam, specced his own HF cam using Crane's shelf lobes, and found 96 HP. That's why guys like Vizard are above guys like Crane. Well, Harvey is long dead. But that doesn't change the point.
Sadly, most of your local engine machinists are solidly on rung 3, a few have a foot on rung 4. Most of the guys with even one foot on rung 6 are inaccessible to the average car enthusiast.
The 2 guys who keep winning the annual Engine Masters Challenge? the old guy who does Chevy, and the other is Jon Kaase. They each have a foot on rung 8.
Gm and the others, with their billion dollar computers? They have one foot on rung 8, but the other on rung 1, for an average of 1. That's Atilla math right there :-)

Atilla the Fun

So, first let's look at exhaust opening. It is specced in crankshaft degrees before bottom dead center. So it is opening while the burn is still pushing the piston down. If you have a big charge with poor flow, this is a good thing. Especially as rpm and static compression increase.
But for modest rpm, and modest static compression, opening the exhaust valve later will help torque by making the burn keep pushing on the piston. At lower rpm there's more time for the spent charge to get out.
At high rpm, a late exhaust opening loses that exact gain because of trying to push the spent charge out.
It's very much a balancing act. You don't need an early exhaust opening to get to high rpm, and have that rpm give useful power. It depends on so many factors.
Early exhaust opening always makes for hotter exhaust valves, and a louder exhaust sound.
And from my own testing, a later exhaust opening helps low-rpm torque more than an early intake closing, while the late exhaust opening hurts high rpm power less than an early intake closing.
I can't stress enough just how combination-specific it is.
Good dyno numbers are so different from how it feels to drive it.
Like for instance a single plane'd LM7 with a true EO of 60 degrees will still give relatively impressive torque numbers down at 1600 rpm, it's true. But fit it with a 1500 stall converter, and watch the tach as you take off. You'll doubt the dyno results until the tach reads over 3000 rpm. Then by 4000 rpm you'll be praying to a whole new god, so to speak.
Go drive a stock-internals L69 with a better intake, air cleaner and cat-back. And a fresh timing set. That cam has an EO of about 36 degrees, when the timing chain is new and not yet stretched.
Rated to give peak HP at 4800 rpm, but it feels like it's really at 5500. And the '92-'97 LT1 is the same story.
That's good rpm from a late EO, and you won't get that from any aftermarket shelf cam with the same EO, but that's an issue for later.

Atilla the Fun

BTW, the higher the static compression, the faster the pressure falls off, so earlier EOs have less effect on low rpm torque.

mw66nova

iTrader: (13)

atilla, would you mind spec'ing a cam for my max effort n/a 1/4mile machine? when i say max effort, i mean, max of what my budget will allow, lol. if you're down, i'll give you the rest of the combo

Atilla the Fun

let's get to it. Maybe teach everyone something. I'm still gonna pursue the rest of the answer for JamieSweet. Doing both might confuse a few people, but that's what five7kid is for, right? :-)

mw66nova

iTrader: (13)

lol. alright. first let me start by saying that the basis of the build is fairly budget minded. and the details are still being hammered out as i can get money.

i have in the car now:

-370ci 11.5:1 SCR, diamonds, eagle h-beams, stock crank
-PRC stage 2.5 cnc ported ls6 heads
-super vic intake
-carb size is up in the air, but i'm probably going to run an 850 porform
-msd 6010
-hawks 1 3/4" headers (btw, they DO have a 1 7/8" header in the works)
--3" duals x-piped exhaust, moroso spiral mufflers

th350, manual valve body, transbrake
-converter to be determined based on camshaft selection
-4.11's in a Moser 9". i have 4.56's on the shelf too that can go in
-275/60/15 MT radial (and i like it that way, lol! it's a class thing...)

-race weight should be 31-3200lbs.

what else do you need?

-my only real requirements are that it runs on pump gas, hydraulic roller, and it can make a 30mile cruise

Atilla the Fun

You're a good candidate for a bottom-of-the-page cam. This is a race combo far wilder than my expertise covers, and I admit it freely. I suggest you log in to www.ls1tech.com and send a PM to Patrick G.
I do street cams for street drivers. This isn't.
Sorry you typed all that for nearly nothing.
Back to Jamie.

mw66nova

iTrader: (13)

lol, it's ok. i was merely looking for more opinions. i've got a camshaft that's in it right now, that's NOT optimized, that i'll finish the season with, it's a 232*/240* .595"/.608" 112+4 installed on a 109ICL, and i'm thinking something like a 239*/248* .649"/.621" 110lsa on a 108ICL will probably do well for this setup....

Atilla the Fun

I'm thinking you're looking at a 7200 rpm shift point. IDK if you can get HR to function above that with 1.7:1 rockers. At those RPM, intake port volume is everything (nearly) and you'd find tenths with MAST heads. They're so far beyond anything else on this planet, there aren't words. Get the medium bore version, and be amazed. They rival AFR's best BBC heads.

mw66nova

iTrader: (13)

well, these heads have zero miles on them basically, so i'm going to stick with them till i'm done with school, lol. i'll be sure to hit MAST up on the next build.

7200rpm is about what i was planning on...i'm using ls7 lifters, and stock rockers with a truniun upgrade. converter is going to be a 9" unit with a 44-4800 rpm flash speed.

Orr89RocZ

iTrader: (20)

I know of a few guys that have gone beyond 7200 with 1.7 rockers on lsx setups with hydraulic rollers. The whole package from valve springs to cam lobe need to be spec'd together. Light mass, strong pressure and right cam lobe will get it done. My friend spins a 4.8 motor to 7500 using stock rockers and hydraulic roller cam.
But yeah for your setup it sounds like a 7200 rpm shift point is all you need. Probably can get away with less since its a light car. What ET you looking to run? An easy 450whp combo can be made there without even touching 7K rpm and be very streetable and thats enough power to go 10's in a light car with good stall/gear. 475-500whp is easily in reach as well with a 370 with those heads and abit more cam.

mw66nova

iTrader: (13)

i just wanna run 10's...how far into the 10's will be determined later i guess. i'm going to tackle some 1/8mile stuff this year too...i'd like to run a 6.99 on motor....i wouldn't think that'd be a big deal.

Orr89RocZ

iTrader: (20)

You'll get there no problem at 3200 lbs or less with that motor and a cam like the MS4 or similar. Since you have a single plane you should get a custom grind since most lsx cams are designed for the lsx style EFI manifold, but mid high 230's duration will be all thats needed and probably shift by 6800 and you'll be in the 10's.

1989GTATransAm

iTrader: (3)

For a custom cam you might want to give Mike Jones a call. Here is his web site. He does a lot of cams like what you are looking for and has an excellent reputation. I know Orr and myself use his cams on this site.

http://www.jonescams.com/2006catalog_001.htm

Guest

So now we're moving to Exhaust Closing? And after we cover all 4, then you're going to tie them all together? ( I hope )

Atilla the Fun

yep. Exhaust closing is possibly the simplest of the four. Earlier gives a better idle quality, but later gives built-in EGR. Closing it later lets you have a decent exhaust duration without an early EO.
to me, early is up to 15 crank degrees before top dead center, while late is right at top dead center, both measured at 0.050" tappet lift.
that was easy. Up next: Intake opening.

Atilla the Fun

IO: GM has taken to putting it about 10-20 degrees after TDC, for no good reason. It belongs somewhere between 5 degrees before top dead center, and 5 degrees after. We're still using crank degrees at 0.050" tappet rise. Earlier opening helps top end, late opening helps idle quality.
If your intake opens before the exhaust closes, you don't just get overlap and built-in EGR, you also get a cam that won't pass a tailpipe sniffer test.
Assuming good heads, you don't need overlap to make power to 6000 rpm in a 305-383. In a newer LS engine, make that 6500, up to 376 cubes. In a BBC, make that 5500 for up to 454, maybe a 502, and 5000 for 496 on up
If you're turbocharging, then late is better. If you're adding a positive displacement supercharger, then early is better. If you're adding any power adder, whether boost or nitrous, then try to avoid having overlap at 0.050"
That's enough of that.

Orr89RocZ

iTrader: (20)

What type of cam specs would you say this would start to become an issue? Reason I ask is there are some fair sized 224 deg intake, 224-228 deg exhaust type cams passing emissions in LSX cars in california (an probably bigger cams than that in many different sized LSx motors), and there are several members here with motors ranging from 350's to 406's with cams in the 224-230+ deg on the intake passing cali emissions which is incredible to say the least, because these cars are up near 380-400 whp and still passing emissions.

I dont have all the cam specs handy but could look them up to get an idea. The comp xfi 280 seems to pass just fine in a 350-360 inch motor and has run in the 406 motor and passed. its 280/286 I think, 230/236 on a 113 lsa. ICL i believe would be 109. I think the actual valve events are on comps website or you can try to calculate them from those.

01-02 LS1 motors dont have egr and feature a cam with slightly more overlap (tighter LSA than the 98-00 cams) to help the self egr effect. Passes just fine, but the cam duration numbers are a touch less than the 98-00 cars but makes as much power due to slightly better LS6 intake.

This thread is in the LTx/LSx section so I bring up sbc's since they are similar to LTx.

I was worried that Houston would have strict emissions but I found out they just did an OBDII check on my 99 TA, so I have all the codes turned off for EGR/AIR/etc. (LS6 intake now so no egr but still have AIR on the car). I think based on that you can throw in any cam you wanted and still pass as long as it visually has the stuff needed.

Atilla the Fun

Intake duration is NO guide at all as to what's clean and what isn't. I see I need to start another thread about emissions cams. I don't want to get too far off topic here.

Batass

I'm building an S10 with a 5.3 for a daily driver. I've been debating the cam for a while. I might just leave the stocker in. Its probably going to be plenty fast with a 6 speed and taller gears. I've lately realized how important low end torque is to me. Power is when I push the pedal! Instant power and more response feels like more power.

The camaro is a different story. xr288hr-236/242 110, single plane, 750 carb. I'm losing the forced induction. Soggier than I like on the bottom, but I might wait until I swap over to a stick trans, dual plane, and 4.10 gears. Its a weekend warrior and I want as much midrange as I can reasonably get.

I've enjoyed reading your post. To me off idle tq is extremely important, but its a hard thing to get people to understand and realize. Some people can't get over numbers and screaming motors. I don't know if you can give someone what they really want when they don't even know what they really want. I sure didn't when I started building my car.

Atilla the Fun

I think 99% of the people who argue with me are under age 30, and that's too young to be willing to concede the value of experience. I do know what they want, better than they do.
It's nice to hear from someone who's arriving at this end of the thing. Thanks.
The stock 5.3 cam does have short duration, which should make for unbeatable off-idle, but that late intake closing just ruins it. And the lack of lift...
If you're gonna keep the stock 5.3 cam, get an aftermarket timing chain set that'll let you advance the cam at least 4 degrees. Then find some 1.85:1 rockers.
If you're inclined to try a cam, I'd suggest COMP's 3707 lobe for both intake and exhaust, on a 110 lobe sep, ground 2 degrees advanced. It'll be fine with either stock or shaved heads, stock or TEA porting. You should do pushrods. It'll have a good idle, and it'll break whatever's attached to the back end of it, to 5500 rpm. It's a mid-range torque cam. It'll be best matched to the truck intake and a cowl hood. If you can find 1.625" long-tubes, it wants those.
With 0.554" lift, you'll need a set of '01-up LS6 / Z06 springs.
Small, infrequent hits of nitrous would be okay, but this isn't a cam for regular use of nitrous or a supercharger. It is a good choice for MPG, and it'll do great with turbocharging. It will easily pass a California tailpipe sniffer.
With shaved but unported stock heads, I expect this combo to exceed 400 ft-lbs at the crank.

Batass

I have a friend that thinks his fox mustang makes BIG power. I know it doesn't make over 300hp, its just in the right spot. The car is really fun, and though he religiously revs it past 6000rpms, its clear to me that it has peaked already not much past 5300. He would be sorely disappointed in the honest power it makes, but to trade anything off the low end, would make it less fun. To me anyway.

Holy cow, 400 ft/lbs in a stick s10 daily driver would be a blast. 1 5/8 headers are available, but long tubes are real pricey and a pain in the neck, running around the frame through the fender.

Thanks, I'll take your word for it when I decide to change cams. Extra power is going to be the last thing on the list.

Atilla the Fun

Having driven a V8 S-10 of my own, all of summer 2009, I can say that a torquey V8 is a problem with traction, whatever you try, but once you're in the top of second gear, with a supercharged Mustang GT still in front of you, then you'll be wishing you had more HP. The Mustang got the jump at the light, but I never reeled him in because of HP. S-10s are aero enough to hit 35 mpg with a small engine, but that's at 55 mph, with stock tires. Add fat rubber and more speed, that boxy shape needs horses.
Have fun with it, and best of luck!

Guest

Ahem..Intake Closing?

Atilla the Fun

Intake closing: The most critical of all, because it has to match both your static compression ratio, and your rpm range. this really shouldn't be attempted until you have the best heads you can afford, and this should then determine the pistons, removing compression from the equation, making it no longer a problem. The flow of the heads, and the cubic inches under them, will determine the rpm range. Then you can choose an intake closing point to match, then choose pistons to match that.
Earlier IC builds low-rpm torque, but hurts high rpm breathing. This goes with low static compression. Later IC is the opposite. When using forced induction, you can fudge the IC later. With nitrous, fudge it earlier.

Homer

iTrader: (1)

Um, okay you lost me on that one.

Atilla the Fun

are you 60 yet?

Homer

iTrader: (1)

Halfway. About ten years into marriage now. I'm finding that like wine, wives get more expensive with age.

ls6iroc

iTrader: (1)

Atilla,
i have a stock 2002 ls1 with ls6 intake
hawks 1 3/4 lt with 3" collector no cats
4l60e stock converter
9 bolt 2.77

i have a set of stock 243 heads that i plan to install this winter. and i am going to upgrade my rear suspension with probably a 12 bolt with 3.42 or 3.73

whats a good cam for the upgrades? i don't plan on doing any high rpm's. thanks

Atilla the Fun

I have 2 cams in mind, because you have 2 axle ratios listed. If you go 3.42:1, then try Lunati's smallest VooDoo LS1 cam. If you go 3.73:1, then try Speed Inc.'s Trailblazer SS cam.

ls6iroc

iTrader: (1)

thanks for the help.

Guest

So, back to speccing a cam, you never did turn it all into something we can use. Like some rule-of-thumb guidelines.
BTW, the 350 you built runs great! It ran a corrected 12.4 without spray! Thanks again! See ya at the cruise-in, right?

Atilla the Fun

guidelines and rules of thumb? easy. But the way this forum mangles charts when you type them, it's hell. First, here's a good relationship between intake closing and SCR @ sea level with iron/alum/LSx heads: 30*=9.0/9.5/10.0:1, 35*=9.5/10.0/10.5:1, 40*=10.0/10.5/11.0:1, and 45*=10.5/11.0/11.5:1.
Now, the relationship between intake closing, and the rpm range, for BBC/SBC/LSx: 30*=1000-4500/1500-5000/1000-5500, 35*=1500-5000/2000-5500/1500-6000, 40*=2000-5500/2500-6000/2000-6500, 45*=2500-6000/3000-6500/2500-7000, all assuming HR with beehives, decent-flowing heads, headers, and no boost. LSx assumes 3.622" stroke, NOT 4.000" With 4" stroke, shift the rpm numbers down by 500.
It's safe to use a half-ratio less compression, but unless you live above 2500' elev., be cautious about trying a half ratio more. Above 5000', you can add a full ratio.
If you do live at high elev., but regularly make trips to a lower elev., choose the SCR to match the lowest elev. that you regularly drive at.
If you follow these guidelines, you'll be fine with pump premium unleaded, even on hot summer days. Unless you're trying a 45*-IC cam with 2.73:1 axle, you should all realize what an extremely horrible mismatch that would be.

Atilla the Fun

I found this on www.ls1tech.com, and while it's all wrong for daily driving with a 700R-4 or 4Lxx-E, it'd be fine with a very-overgeared stick combo, so long as the highest gear in that stick is no taller than 0.68:1. This cam will NOT pass any emissions test, or I'd try it in my Fiero. They shoulda extended the test to 7000 rpm, I'd surely hold the first three gears to 7000 when racing. That's why ARP is in business.