View Full Version : How much cam and not need a "tune"?


More power!
05-01-2005, 08:50 AM
Having read about the drivability issues after putting medium-to-large cams in LS1 engines, how large of a cam upgrade can be done and not need to "tune" the PCM? 224/224? Z06 cam? I would like to keep the stock manifolds and cats to meet emissions, keep the car quiet, keep the exhaust smell reasonable, and because most headers apparently cause the O2's to run colder and the car to run pig rich -- which requires PCM tuning to fix. So cams with minimal or no overlap are on my mind, since they will not be as affected by the lack of headers.

At what point does the cam go from being a "slap it in and go" part to a "slap it in and spend countless hours tuning the new-found gremlins out of the car"?

Typical gremlins -- stalling, poor idle, part throttle bogs or stumbles, etc.

blacktransam
05-01-2005, 09:10 AM
dude these cars could use a tune stock.. any cam u put in there needs a tune just sometimes u don't have to have one..

PREDATOR-Z
05-01-2005, 09:22 AM
All cams need tune.
There is a NEW Thunder Racing cam the 214/230 .600/.578 117 lsa that is called CheaTR package.
It will need tune but fits all the descriptions you describe.

M6HuggerSS
05-01-2005, 12:27 PM
bro.... if you are going to keep your stock manafolds, cats, catback, etc... and
dont want to spend any $$$ for a tune.... dont bother with a cam.
its out of your leauge... now if you want MORE HP and want to get there most out of your car.

then get all bolt-ons FIRST.... headers, TB, lid, cat back, ....
THEN get your self a nice cam kit.... springs, pushrods, ti ret. gaskets, etc.
sounds like you would be a 224 sized guy....
un-tuned it will idle a little ruff (sounds awsome) it may have a litttle flat spot
under 3K (mine did) and it will probly have some low speed surging...

but a good tune (350-500 bucks) will not only gain you MORE power but it will
(depending on the tuner) make it drive smooth as silk (at least mine did)

and thats how you do things properly! if you are not up for it. and are not up for doing ALL supporting mods, dont do anything!

good luck

99'Formula
05-01-2005, 12:54 PM
A tune is a great idea for anything you put on your car. It will allow you to get the most out of your car. Why spend all the money and only receive half of the performance?JMO

Brandon Boomhauer
05-01-2005, 03:14 PM
bro.... if you are going to keep your stock manafolds, cats, catback, etc... and
dont want to spend any $$$ for a tune.... dont bother with a cam.
its out of your leauge... now if you want MORE HP and want to get there most out of your car.

then get all bolt-ons FIRST.... headers, TB, lid, cat back, ....
THEN get your self a nice cam kit.... springs, pushrods, ti ret. gaskets, etc.
sounds like you would be a 224 sized guy....
un-tuned it will idle a little ruff (sounds awsome) it may have a litttle flat spot
under 3K (mine did) and it will probly have some low speed surging...

but a good tune (350-500 bucks) will not only gain you MORE power but it will
(depending on the tuner) make it drive smooth as silk (at least mine did)

and thats how you do things properly! if you are not up for it. and are not up for doing ALL supporting mods, dont do anything!

good luck Read this man
http://www.ls1tech.com/forums/showthread.php?t=311937&page=1&pp=40

You can make good power with the stock exhaust.

nuzee
05-01-2005, 04:07 PM
I'm running CompCams 206/212 112 lsa. It doesn't need a tune to drive acceptably. I believe their 212/218 114 lsa would act similar. I'm running stock manifolds/cats & torque converter.

I wanted to gain some lowend power without losing any upper-end power with the cam change. The cam does just that. However, the lowend comes on strong right off-idle. A few 100 rpms higher would have been preferable. Anyway, cam change alone netted me a 3 mph gain (87 to 90) in the 1/8 mile. However, I only saw a 1 mph gain in the same 1/4 numbers.

I then installed 1.85 rocker arms and that woke up the upper-end. I gained another solid 2 mph in the 1/4 trap (108 to 110). So, with 206 cam & 1.85 rockers I netted a consistent 3.x mph gain & ~0.3 ET drop. Some would venture an estimate of 30 horse power gain based on the 1/4 trap.

The engine ran fine with 206 cam only. Idle was just not stock smooth. However, after the 1.85 rockers, the idle became a little rougher. I then tried the HPP3 power tune and the engine liked it. With stock cam, the HPP3 tune gave me bad gas mileage. So, I never ran HPP3 on the street (only at the track). But now with the HPP3 tuning I get the same (even slightly better) gas mileage as with the stock cam.

Anyway, a small cam with stock exhaust can return a decent gain. I feel I got an improvement through out the entire rev range with both mods. If i were to do it over again, I would probably go with CompCams 212/218 high lift LS6-replacement cam or get a custom grind 208-210/216-218 .550-.560 lift 113-114 cam. In other words, a cam that is very close to what I have but has the lift of the 1.85 rockers ground in.

If my goal was strip first, street second, then I would pick a much different cam & not use stock manifolds & torque converter. The best combination for you really depends on your goals!!! That cannot be emphasized enough. Good luck

More power!
05-01-2005, 05:01 PM
Thanks for the link to the stock exhaust max effort h/c package! That is what I am after. And from reading the whole thread, it appears that tuning is NOT needed for the 214/230 .600/.578 117 lsa cam from Thunder Racing. Yes, they did a very small amount of HP tuner tweaking, but only items they touched were the rev limiter to 6800rpm and taking some fuel out at low temperatures to cure the "shake" at a dead cold idle. Stock A/F tables, stock timing tables. I could deal with a little cold-blooded character in the car for an extra 30hp.

The statement "do it all or don't do anything" is really a bad thing to say to anyone new to hot rodding. With that mind set it will take $4000 in bolt-ons, chassis work, transmission work, differential work, and tuning or programming the PCM yourself to get anywhere with these cars? I certainly hope not! I will likely end up buying LS1 Edit or HP Turners software eventually so I can raise the rev limiter a bunch and change the speedometer for different rear gears -- at first. I don't have a wideband or dyno at my disposal, so chasing A/F ratios would not be the main reason to poke around in the PCM for me. Maybe through the advice from other people who have tuned their cars I could try trimming fuel maps when I have some time to fiddle with it.

FWIW, from posts on this board, it appears that a "tune" of the PCM is worth somewhere between zero and 30hp depending on the degree of modification. People doing dyno tunes reporting gaining 10-20 hp for $500 is not a good thing! $50 per hp is a really poor modification cost/benefit ratio. Now if after putting a big cam in or bolting on a set of uncoated headers the car won't run, gets 3mpg, backfires, surges like crazy, or whatever, the "tune" is a good idea for sure to fix those problems. I was asking what mild cams don't cause all that grief. So far they appear to be:

LS6 cam 204/218 117 lsa
Comp Cams 206/212 114 lsa
Comp Cams 212/218 114 lsa
LPE GT2-3
Thunder Racing 214/230 117 lsa

The lobe separation angle of 114 or larger combined with a split bigger exhaust grind appears to be the key to stock exhaust performance.

Brandon Boomhauer
05-01-2005, 05:48 PM
I'll have to disagree with your thoughts on tuning. Tuning is not just for peak horsepower. Alot of midrand and lowerend power can be gained with a capable tuner. So many things can be done with LS1 Edit and HP Tuners, its unreal. Tuning fixed idle problems, fuel tables, etc etc. I had a tune after longtubes and duals because my A/F was 13.7:1 which was too lean. With that same tune after the cam i made 394 on the dyno, after tuning I hit the 403.5 that I'm at now, with quite a bit more midrange power. Also w/o tuning a cam such as mine wouldn't be worth a damn driving anywhere. Tuning is a very critical part of any engine modification in my book. A completely stock car can gain power from tuning. Get a tune.

More power!
05-01-2005, 06:24 PM
See, you gained 10hp with your tune. $500 for 10hp.

I am not arguing that tuning is a nice thing to do to fully optimize the car. Sometimes tuning the PCM progamming is required to get the car to run at all. I did not ask about a combination that needs tuning to work at all. I asked what aftermarket cams can run in an LS1 without tuning. A quirk or two can be tolerated.

:bang:

Brandon Boomhauer
05-01-2005, 06:35 PM
Yeah So i gained 10rwhp with the tune, if i had my lt/dual graph and cam graphed laid on top of one another, plus tuned and not tuned cam graph you would see the point of the tune...

blacktransam
05-01-2005, 10:32 PM
i used to not be worried about a tune but now i wouldn't be with out it.. take it from some one who went both ways driving a modded car with out a tune is ignorant.. better driving and better gas mileage with the tune.. it pays for its self..

nuzee you would see more gains with a tune..

Brandon Boomhauer
05-01-2005, 11:53 PM
i used to not be worried about a tune but now i wouldn't be with out it.. take it from some one who went both ways driving a modded car with out a tune is ignorant.. better driving and better gas mileage with the tune.. it pays for its self..

nuzee you would see more gains with a tune..http://www.ls1tech.com/forums/images/smilies/LS1Tech/gr_judge.gif there ya go i almost forgot the gas milage part..

SmokingWS6
05-02-2005, 12:08 AM
My car gained from a tune when it was stock. it may 'run' with out a tune but your not getting the most performace/economy out of it.

nuzee
05-02-2005, 02:20 AM
nuzee you would see more gains with a tune..

no doubts here. I wish it was easy for me to just drive to a dyno-tuner and be done. Its not. I just have to make do with what I have available. I think I've done a decent job with just the HPP3 so far. I am contemplating getting tuning software or a Vinci/Crane handheld to mess around with. I find it easy to use a handheld at the track to make small adjustments. Its just too bad the Crane unit doesn't allow incremental shift-point adjustments.

Byter
05-02-2005, 08:34 AM
Getting 10 HP from a $500 tune is NOT the point. You may get 50 HP from the tune, you don't know, THAT's the point. Why spend $400 for a cam, cash for oil, coolant, sealants, etc., all of the time and effort installing it, and then wonder if you're getting everything out of it by not doing the tune. There are SO many variables in each of our cars. Your cam swap could possibly degrade performance, gas mileage, etc. Do yourself a favor, work a few hours overtime, or cut some grass, or do anything to get the $500. The piece-of-mind of knowing you have a fine running machine is worth it.

freakynipples69
05-02-2005, 08:36 AM
bro.... if you are going to keep your stock manafolds, cats, catback, etc... and
dont want to spend any $$$ for a tune.... dont bother with a cam.
its out of your leauge... now if you want MORE HP and want to get there most out of your car.

then get all bolt-ons FIRST.... headers, TB, lid, cat back, ....
THEN get your self a nice cam kit.... springs, pushrods, ti ret. gaskets, etc.
sounds like you would be a 224 sized guy....
un-tuned it will idle a little ruff (sounds awsome) it may have a litttle flat spot
under 3K (mine did) and it will probly have some low speed surging...

but a good tune (350-500 bucks) will not only gain you MORE power but it will
(depending on the tuner) make it drive smooth as silk (at least mine did)

and thats how you do things properly! if you are not up for it. and are not up for doing ALL supporting mods, dont do anything!

good luck


:werd:

GuitsBoy
05-02-2005, 08:58 AM
10 PEAK HP is not the point. You may gain 40 ft lbs of torque down low, and the car will likely be infinately more drivable. A tune is well worth it.

Oh, and really you should brake down and get some longtubes, the problems are not as big an issue as it may seem. I ran LTs with cats for a while and you couldnt tell any difference from stock unless you popped the hood or stepped on the gas.