After toying with a supercharger, I have gone down the road to replacing the cam.

I need some real advice.

I want to pass smog in California. Dont want to go too aggressive and hurt the motor.

What I have decided to do is:

Port the oil pump.
Upgrade the timing chain
Springs, seal, pushrods

SO, what cam do you reccomend? This is a 2006 mn6, Z51, with long tubes, cai, etc. Currently at 385 rwhp, would liek to get into the low 400's and have a reliable motor that I dont have to worry about destroying or having reliability problems.

I am looking for more HP at the higher end as the low end seems fine.
Your input is greatly appreciated.

 

So Do You Still Have The Supercharger Or Were You Just Toying With The Idea???

 

Maybe your tuner in Irvine could answer the question. He should be familiar with the smog issue in California.

 

Ed,

I don't remember if we had this conversation, but in case you did not know, I've been down this road. I looked at all the ways of getting NA power in my C5... built LS1, LS1 stroker (382), LS2 stroker (402), C5-r (427), etc. I eventually wound up with an LS2-based 402 stroker. Like you, I had the same concerns. I'm certain that with your stock block LS2 you can pass smog (sniffer anyway) with a 224/228 cam. Stay under .600 lift, and either a 114 or 113 LSA.

HTH!

 

I am on the same boat. I plan on installing LG PRO long tubes with catted X pipe, B&B Bullets, in addition to the Callaway HOnker CAI. Keep in mind, that the long tubes will already cause us to fail emmissions here in California. I am also toying with the idea of a cam, but I do not want an aggressive Shaky lope, stalling, or bucking. Is there a no compromise cam that will increase power throughout the entire RPM range? I do not want a cam that will compromise lo to mid range torque loss, at the expense of added peak top end HP. What are the disadvantages/advantages of each?

1) 224/228
2) 224/230
3) 228/232

Yes, I also want to keep the intake and duration under .600, and have been told to stay with a 114 LSA.

 

Thanks all for the comments.

Regarding my "tuner" in Irvine. Yes, he is the best, ultimatley I will trust his decision, as I am an EXTREMELY **** person, I do not like to leave anything to doubt.

I solo'd my first plane when I was 14. At 15, my instructor 'fired" me and said I need a new instructor. (maybe I had bad breath)

After 5 flight instructors, I realised that each one gave me something different in wisdom and skills. It doesnt mean one was better, just that they all reinforced each other and each made me think of issues I never would have thought about.

Variety is the spice of life.

 

If this tuner is Orange County Corvettes, you may want to inquire about SLP 1.85 rockers + the LT headers. They say they have several cars doing 398RWHP with just this combo. However, you will automatically fail smog with the headers because they won't pass visual.

For H&C no headers, the consensus for CA seems to be a 222/222 .580 144 LSA or wider to ensure a pass. AFR205 heads, of course. That gets you 400+ with a tune.

 

If you're already at 385 HP, almost any cam will get you over 400 HP, even a very mild one.

Since you already have LT headers, I'm assuming you have found a way to pass visual inspection.

To maintain street manners, emissions, and gas mileage, you want to keep your valve overlap to a minimum. Of the cams you mentioned, the 224/228 on a 114 will do best, will give you solid gains throughout the RPM band. The 222/222 that was mentioned will also do well, but I wouldn't recommend it with the stock exhaust.

Unless you plan to spend a lot of time at the track, and spin the motor over 6500 RPMs, you do not need to port the oil pump. With a relatively new car, you probably do not need a new timing chain, although the aftermarket units are definitely better than the OEM piece. So if it would give you peace of mind, go for it.

The problem with the SLP rockers is that they are expensive, and cost way more than a cam. You will need new valvesprings and hardened pushrods either way. The install cost for the cam is a bit more, but not that much. In general, SLP rockers are great for stealth, and if you want to claim that you have "stock internals". But the cost per HP is high.

If you want to also get heads, now you're talking another $2K or more, depending on which vendor you go with.

Good luck with your choice. You will get lots of opinions, but unless you're planning to do the install yourself, I'd go with whatever your installer recommends.

 

Get the 224 228 cam as someone already suggested, it is smog friendly.
The timing chain is fine, it's the same one used in the Z06, it's plenty strong.
That cam will drive pretty close to stock and your motor will last as long as it would stock. You will get over 400 HP easily.

 

Because I just did a cam install on my '05 and I re-used the stock timing chain & gears. However, I have had that little voice in the back of my head wondering if I had made a mistake by not upgrading to a "Double Roller" type aftermarket chain. When I looked at the stock pieces I felt they were strong enough !



Steve.

 

Good advice. Ok, so is there a cam that you would go with that you would feel comfortable not changing the timing chain, not changing springs, pushrods, etc.

Basically what cam would you recommend installing alone, without any change to the valve train at all? And, would it be engine safe?

 

You're changing springs no matter what cam you put in there.

 

So basically, since its opened up, go ahead with stronger push rods and a double roller chain?

Sorry to sound like a moron, just trying to understand all this.

 

No, the chain is unnecessary, you can swap it if you want but you do not need to. It is the same chain used on the Z06 which already has 100 more HP
You will need springs no matter what cam you choose, push rods should be used but some will argue that point.
As a general rule, when you replace a cam you also replace:
Springs
Push Rods
Timing cover/oil pump gaskets
front seal
crank bolt
oil/filter

Some vendors will sell all of this as a kit.

 

Dave, Could you tell me the diferences from the cam specs listed below? Whcih is best overall for a daily street driven car? Why?

1) 224/228
2) 224/230
3) 228/232

Yes, I also want to keep the intake and duration under .600, and have been told to stay with a 114 LSA.

 

The timing chain isn't a concern. However, there is no cam you can install that won't require stronger springs. Even if you don't open the engine, and just install higher ratio rockers...you'll still need to upgrade springs as a bare minimum requirement.

Any cam shaft worth installing, and all high(er) ratio rockers, will increase lift. Generally speaking, the higher the lift, the stronger the valve springs need to be, in order to slam the valve closed. The stock springs are capable at stock lift, but not much more. As a general rule of thumb, greater than stock lift (but under .600) requires a Comp 918 or equivalent; over .600 requires Comp 921 or equivalent. Hardened pushrods would not be out of the question either.

 

Based on past threads, I think Dave & I will probably tell you pretty much the same thing. All of those cams will work OK for a street driven car. The 114 LSA will keep the idle pretty tame.

First question is, do you have LT headers on the car already?
Second question is, is this an M6, A4, or A6?

The 224/228 cam is a proven winner, will idle well on an LS2, give you great power. Best used with LT headers, will work with the M6 or auto tranny. With an auto, you may need to raise the idle 50-100 RPMs.

The 224/230 is a variation on the same theme. The extra exhaust duration will help out if your are not running LT headers, & will help the top end a tad. Idle could be very slightly more lopey.

The 228/232 is a more recent grind that has been very popular lately. With this much duration, you should be running LT headers, and IMHO this cam will also do best with aftermarket heads. This cam has a decent amount of overlap, so the idle will be rougher, and you will probably need to raise the idle speed even on an M6. Several guys have reported that this cam, with proper tuning, can be quite docile on the street. You should get great power with this cam.

 

Yes, I have an 07 Z51 MN6. I will have long tubes, catted X pipe, cat back and CAI. How much HP and TQ would I be giving up with the 224/228 versus 228/232. I would think that the 224/228 would idle smoother?

 

Any estimate on the power differences between the two cams would be a guess --- I'm thinking that the 4 extra degrees of duration might get you an extra 10-15 hp. Do a search on the tech forum, and you should find some results. Here's at least one thread that might give you some info.

http://forums.corvetteforum.com/show...ight=224%2F228

 

with the LS2 factory intake made 410rwhp/384rwtq. With the typical headers, cat back, tunning, etc. and the above mentioned cam.

Added a FAST 90 intake: made 425/405.

Added 215 ET heads made 461/435

BTW there is no upgraded timming chain ( like a double roller ) because it woun't fit due to the cam sensor being in the front of the motor. They only fit LS1 motors. I put a new factory chain on, and I haven't herd of anyone with a chain failure yet. As for smog, well....anytime you start increasing the time the valves stay open ie duration, the ppm reading is going to surpass the acceptable levels. Even with the cam listed above. I really don't know if the car will pass the sniffer. That's years down the road and the car will be gone by that time. Only to have another.