I currently have a Comp Cams 218/226 527/535 112 cam. The best dyno results I've gotten out of it were 402/378, but usually it's in the high 390's. It ran 12.33@115 pre-LS6 intake on 16" Nittos, and ran 12.7@114 on 17" Michelin Pilots. I'd like 1/4mi speed to be higher (even though I no longer visit the strip), but would like better driveability below 2000 RPM's.

I want to maintain stock or very-near stock driveability, and I want as close to 30MPG as possible while cruising in 6th gear ~75MPH, and would like no worse than 15MPG in the city. I currently get ~26MPG@77MPH and average 12-13MPG in the city.

I also want maximum area under the curve and don't want my ideal shift RPM to be higher than ~6400. I have a stock shortblock, with CNC heads supposedly angle milled .030, which in turn have 2.02/1.57 valves, and 918 springs.

It's a complete daily driver since I'm tired of fixing things. To this extent it won't see drag radials, slicks, or different gearing (due to fuel economy only). I'd like my valvetrain to be as reliable as all stock, but with high-performance parts - screw these recurring broken valvesprings every year. If I can get a cam which optimizes my other parts, wonderful. I would prefer not to lose any further emissions equipment. I want to stay naturally aspirated.

Ideas and/or recommendations?? Yeah, that's a lot to ask for but hopefully I can find something I consider balanced which doesn't involve replacing any other parts.

My mods: K&N, Whisper Lid, Stock MAF, Whisper MAF ends, stock TB, LS6 intake, CNC Heads, stock shortblock, Comp Cam, Grot headers & y-pipe w/ cats, cut-out, stock cat-back.

TIA!!

Jim

<small>[ July 06, 2002, 08:32 PM: Message edited by: JimMueller ]</small>

 

Sounds like you have a good cam. What are you not happy about with the current one?

 

It almost sounds as if you'd be better off putting the stock cam back in...

If you're not racing the car, and are that concerned about gas mileage, you would probably never miss the few horsepower you'd lose with the stocker back in it.

Just an idea...

 

What I'd like to change?

- I'd like better driveability between idle & ~2500RPM

- I wanted ~400RWHP before I added the LS6 intake. With that in mind, I still want ~420-440RWHP.

- I don't like having to shift at 6800 to maximize the performance. Technically I'd get more out of it shifting at 7K, but I have a stock bottom end and I don't want to shorten it's life unnecessarily.

- I don't like it lurching off-idle

I don't want to lose power, I just want to adjust where it's being made.

 

I think we have similar goals. How about a 218 straight duration on a 114LSA. Maybe on a 108CL w/ 6* ground in to bring the power band down a bit? Comp XE grind, but not XE-R. Comp's are smoother running than Lunati's. I'd keep up the lift at .550 w/heads. Valvetrain should last forever with your 918's @ .550. Up the idle to 875 for super smoothness.

The above should meet all your goals. The 112 is hurting you the most re: what you want I think.
You may give up 5-10 off your current peak.. or maybe not, but that's the risk. The increased lift might offset the minor duration loss to put to use your ported head work.

Dunno about peaky ~420-440RWHP. I'd say be happy with 400rwhp and maybe you'll make even more? If you want the ability to play, get a 114LSA/110CL 4* Advance and a Cloyes adjustable. Dyno straight up and advanced another 2* at 6* total. Gonna try this soon myself, re: getting the power band where I want.

<small>[ July 07, 2002, 12:09 AM: Message edited by: MelloYellow ]</small>

 

I never received a flow report on my heads, but others have indicated my max flow is @.550. I read somewhere else that some prefer cams with 20-25% more lift than max since the valve doesn't open instantly. I'll let someone else try that <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

I'm leaning towards a traditional split cam. How much diference between in/ex duration is too much? Would something like a 21x/23x 114 LSA w/ 4* of advance ground in be feasible?

<small>[ July 07, 2002, 02:14 AM: Message edited by: JimMueller ]</small>

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by JimMueller:
<strong>What I'd like to change?

- I'd like better driveability between idle & ~2500RPM

- I wanted ~400RWHP before I added the LS6 intake. With that in mind, I still want ~420-440RWHP.

- I don't like having to shift at 6800 to maximize the performance. Technically I'd get more out of it shifting at 7K, but I have a stock bottom end and I don't want to shorten it's life unnecessarily.

- I don't like it lurching off-idle

I don't want to lose power, I just want to adjust where it's being made.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Those are pretty big task for stock cubes. The 346 isn't that big so you really gotta rev it pretty good to make the kind of power your wanting and to do that requires a larger cam which hurts low end.

I'd say that with you not racing you might be happy with a much smaller cam such as 212/218 or maybe even as mild as a z06 cam. You probably want make 400+ horse with either but it should restore drivability back to near stock, return the bottom end power and still make a lot more power than most cars on the rd.

To keep 400+ and also meet your other goals of low end power and not having to rev the only other option I can think of would be more cubes or forced induciton.

440 horses is not an easy task even when you don't give a hoot about drivability.

 

A Split is a nice Cam, but will hurt driveability. If anything, I'd go reverse split. Both on Duration and Lift. But you're going to give up bottom end if you go too high on duration.

222/218 .555/.550 114LSA 110CL
The XE-R's might give you a bit more power and improve idle but will be harder on the valvetrain.

 

Sounds like you need a straight duration cam,218/218 .561/.561 works great ask Bean-o.
I Have a 222/222 .566/.566 on a 112 for sale but I think you would be happier with a cam on a 114

 

Will Desktop Dyno or Performance Trends Engine Analyzer simulation software correctly model cam changes?

 

Your goals contradict each other and you need to prioritize them. I think a 220/220 114 is the most cam you can run and hope to have power below 2500. I like Mellow's reverse split, I had thought that even a 220/216 114 might do the trick.

I haven't seen very good results posted from the simulation programs, but they might give you an idea of relative performance.

 

I if you want more power. Go with a bigger cam.
Thunder R 224/224 .561 That should do it.

If you want good gas mileage?.........

Try a lighter foot. Not a lighter cam.