Several questions I need help with:

1. What is the highest HP I can safely run on a stock driveline in a MN6?

2. What is the cheapest way to get there, HC and headers or FI? If HC route is cheaper would I need headers to reach max safe HP?

3. Going the cheaper route how much will it cost me? I'll have a shop do the work as I don't have time.

I've read lots of posts doing searches but haven't found these questions answered in a single post.

Should mention car is 80% street use, 20% track. Track use is road course, no drags.

Thanks in advance.

Rick

 

ECS does both FI and HC and I see many of customers that road race stick with HC while I see many 1/4 guys go with FI setups. For Street cars its a mixed bag. Smoothness of FI system or 60s big muscle sound from HC is usually the deciding point.

IMHO since you like RR stick to the HC with your mn6. You can easily achieve 450-500 rwhp which is plenty for RR and also alot of fun on the street.

Yes you should do headers with HC and do not be surprise if your stock clutch needs to be replaced in the future (this would be true based on power level not FI or HC).

I have 3 years of RR on my ECS HC car and about 50 1/4 passes so reliability is there too.

of course if you are RR you should also change to a dewitts radiator with oil cooler. plus maybe upgrade brakes, suspension oh nevermind the list never ends.

I realize this doesnt exactly answer your post, but in the end the cost of HC vs. FI is close so why not go with the setup that is more suitable to how you drive?

 

1. From what I understand, guys are running 500whp (or more?) without problems, if they are running normal street tires. I have also heard that you can tear apart your rear diff with drag radials and 300whp when launching.

2. I think H/C is hands-down the cheapest way to add power on a stock engine, but I think you can go a lot higher with FI on a 346. A do-it-yourself H/C job can cost between $4,000 and $6,000 depending on what heads/parts you buy. I did mine for around $4,400 with a tune, using budget heads. I went with a fairly mild cam and am at 410whp. You can get a good 450whp with a set of AFR's and a mild-mannered cam without too much lope(LG's G5X1E cam 228/232 on a 115 with AFR's has repeatedly hit 450whp), and another 20 with FAST 90/90. I think a FI is going to run at least $6,000 plus tune on the low-end, unless you are buying used.

3. Mostly covered above, except figure somewhere around $1,500 to $2,000 for an install on either FI or H/C. My tuner quoted me $1,600 to install my H/C package, and quoted me $8,200 installed and tuned on a $6,300 supercharger. If I would have used my tuner for an install, the supercharger would have netted me about 480whp for $8,200, and my package now would get me 410 for about $6,000. I just couldn't rationalize $2,200 for another 70whp (although I'd love to have 70 more whp).

I think if you are on a budget, and will settle for 410-450whp, H/C will save you some bucks. If you really want to squeeze a ton of power and still have really nice street manners/idle/etc, and you don't mind dropping the cash, FI would be my preference. I just didn't want to dump that much dough...

 

Thanks guys. EXACTLY the info I need to make a decision. Additional input would be greatly appreciated.

Rick

 

Last year I went the H/C, headers, exhaust (Corsa Pace Car,) Honker, rear (3.90 with hardened shafts) route, and dyno tune. I now have 428 rwhp and 366 rwtq. The car has been well mannered after the mods. My wife has been known to run the kids to school in it. I will tell you that I was a bit conservative with my choices for heads and cam. If I had it to do over again I would go for more juice. You will get very used to the power quickly and will want more.

Enjoy, but understand this never ends.....

 

Last two sentences sum it up

regardless of which one you do, there is always something else that comes with it. Once we cross this line of power, the clutch comes, then the drivetrain, ect, ect.
Happy modding

 

I did the H/C thing, including the usual other stuff, like FAST90, and UD pulley, and already had headers. It cost me about 6k, doing all the work, except tuning, myself, and using high quality parts. If I had to do it over, I'd go with FI. Lots easier to install/tune, and higher power level, with no change in drivability. I ended up with 475 RWHP, and I'm very happy with that, but 525 is pretty easy with most FI setups. One side effect to my mods, is increased gas mileage, from 25 highway, to almost 29 mpg highway.

 

I am wondering what you guys mean by HC????

 

HC means Heads and Cam.

 

The above are excellent suggestions. Here is another option you might want to consider.

In terms of bang for the buck you might be better off going FI. I would look into a used centrifugal supercharger such as procharger, vortech, etc. A good used complete kit can be had for about $3,500. You should easily be able to produce 450+ rwhp with stock exhaust system, although I would suggest gettinga used Ti exhaust system (about $450) to open up the exhaust a bit. Make sure you get the newer brackets like what ECS makes so you don't have belt problems. You will also need a restrictor plate to limit boost or you will not have a motor for long. Get it installed by a competent tuner like ECS, A&A, etc.

Unless you put your foot into it the car will be like a stock car, which will give you excellent streetability. When you put your foot into it, you will take off like a jet.


If you get a chance might want to see if you can get a ride in a HC and supercharged car to see what they are like.

 

I currently have both and if I were to do it all over again, I would just take my stock car in to be supercharged and that would be that. There is more power to be had with the FI setup and the car would behave like stock until you mash the gas. Of course I do like a bit of a rumble so I would probably go with a blower cam at the same time. As for now I have the best of both worlds.

 

I just installed an ECS Paxton Novi 2000 supercharger on a bone stock Z06, 500rwhp/465rwtq with a conservative tune(this is with the original cats/manifolds still in place)

you'd be spending about the same amount of $$ to do that with the heads/cam route, and most likely wouldn't see those Torque numbers

the blower could easily support 700rwhp plus with a forged motor later on down the road

give me a call on Monday, we can go over the details

 

"Highest", "safely", and "run" are all relative terms. Even then, there is no single point where it goes from "safe" to "unsafe".

It seems to me there are two major areas of concern: losing a piston and breaking something in the drivetrain.

The latter is more a matter of how well you hook and how hard you drive than anything else. You can dump the rear out of one of these cars with a dead-stock LS-1 if you dog it hard enough. There are also guys running 600+ rwhp on stock MN6 drivelines with no troubles. Note that they are not drag racing every weekend on ET Streets, nor powershifting every gear.

As to dropping a piston, that is fairly common on stock shortblocks combined with N2O or turbo/supercharging. The stock pistons are simply not designed for this. Run a little lean, or a little too much spark advance, or get a tank of sub-par gas, and you melt the ring land (usually on #7) and that toasts the piston and often the block, etc.

The general consensus might look something like this: for an all-stock MN6 driveline, avoid anything stickier than good street tires or maybe DOT roadrace tires. Don't powershift. Don't drag race it every weekend. If you do that, you can have good driveline life up to around 500, maybe 600 rwhp. If breaking things would cause great financial pain, better stick to 500.

Clutches are an issue even with the stock engine. Figure on replacing it sooner or sooner.

As to the engine, certainly FI is cheaper for "the most" power - until you lose #7. FI is not cheaper if you have to buy the FI unit and a forged shortblock. Especially if you do those things out of order and have to pay for labor twice. To be fair, there are guys out there who have multi-10k miles on their stock-shortblock FI cars. But, they tend to be pretty conservatively tuned, and they tend to not beat on them. Once you get much over 500 rwhp, 550 at most, on a stock shortblock, the clock is ticking. Again, if replacing a blown engine would not be financially traumatic, cool deal. Otherwise, I'd think carefully.

Another consideration is that you mentioned road racing. NA cars are generally strongly favored over FI cars for road racing. Reasons are that an NA car can make all the power you can use, and a NA car tends to have more predictable and controllable power delivery. But the biggest reason is that FI C5s tend to have serious cooling issues when road raced. This just leads to more expense. This is not to say that an FI car can't work for road racing. Just that it is more work, money, and hassle.

Again, there is no "max safe". But, to your point, somewhere around 450-500 rwhp is generally considered pretty safe on a stock shortblock. At the higher end of that you're starting to push things.

It would cost roughly the same amount to get to 500 rwhp via HC and FI. With the HC setup you would be talking high-quality parts and a fairly high state of tune, so that means a rough idle, etc. For FI you're just talking about a good kit on an otherwise totally stock engine.

Good headers are worth 15-20 rwhp on a mild engine, maybe 30 on a hotter enigne. They are not necessary, just traditional. The C5 has a particularly good factory exhaust system, so you don't gain as much as with many cars. Still, to hit 500 NA you're going to need them. FI, not so much. You pays your money and...

500 rwhp, through a shop, is going to be $7500 or so, at least. I would budget around $10k, to also cover a clutch and "etc". It adds up fast.

There will probably be guys saying that's way high. They didn't keep their receipts.

All just IMO.

 

One more thing: the most important part of a deal like this, BY FAR, is what shop you use. Find a really good, respected shop. Tell them your goals (be honest!) and budget. Then let THEM tell YOU what's the right way to go.

 

Your posts are very informative and cover many bases.

 

I did the same thing and love the sound, but if power is what you are truely after buy a used blower from here on the fourm. 3-4k and get over 500 to the tire.