Good evening all. New to this whole Corvette thing, but learning very quickly. A 2000 C5 that was built up and modded in 2000 literally fell in my lap. I knew very little about the car when we got it other then it was supposed to be a 383 stroker. The build was done in 2000 with 200 miles on the car. The car currently has 19,000 miles. When I got the car, I took it and got it looked over and thought why don't we dyno and tune it and see how it does?? Car made 417 to the wheels and 418 torque. Car at the time had a Callaway Honker Intake, factory stage 2 heads port and valve, cam (not sure, but on the smaller side), 1 5/8" headers, what I believe to be early Corsa exhaust and that's about it. Felt great for a while and I thought, I need some more power!!

I did a bunch of research and found a guy who worked on and tuned LS motors. He thought we could get more by doing a LS2 Throttle body, Fast 92 Intake, 1 7/8" headers and we already needed to do the dampner so why not do a slightly larger cam. I bought a Mamo Ported LS2, Mamo ported Fast 92 intake, 1 7/8" headers and a 236/238 115 cam (per tuners recommendation). Put the car back together and made 477 RWHP and 435 TQ on his dyno.

I will say the car feels faster especially above 4000rpms and makes power longer. I would say this cam is a little tougher to drive around town, not bad, but a little tougher. I would say Lower RPM feels like it has less power for sure (not sure I like this) higher RPMS more power? Is the 236/238 115 cam the wrong choice, I wouldn't have thought losing torque would be a good thing? Part of me thinks I would have been happier if I had left the other cam in and just did the other mods. The other cam would pull pretty hard from about 3200. The car felt like it had more useable power if that makes sense?? Or is this what you would expect from the parts I added? Where did we go wrong, or is this about right. I spent allot of money for 50hp lol. Thanks

Please see dyno below....
Blue Line 383 stroker Stage 2 Factory Ported Polished Heads with Cam, Callaway Honker, Exhaust and 1 5/8" headers.
Red Line is same Motor with Mamo Ported Fast 92, Mamo Ported LS2, 85MM MAF, 236 238 115 CAM, 1 7/8 headers. Final dyno on this set up was 477rwhp and 435 torque

 

This is the original CAM that came out of the care. If anyone has any info on that, it might be helpful. Thanks

 

No, everything here looks about right. Not bad power for a daily driveable 383. Takes a lot of money to make a little hp when it comes to NA. What you got looks good. Should be good for low 11s with crappy suspension and bad air. 10s if you get it dialed in.

 

Well, a cam is a pricey upgrade for what little you get. But if you're looking for hp...Horsepower is made in the heads. The cam just compliments the heads to get the most out of them. Bigger isn't always better.

 

Good results!

NA upgrades are expensive but you picked excellent quality parts. Mamo's ported intakes are A++.

2000 Vette with motor build in 2000, guessing the car has ported heads (853 or 241)? If so that's an outstanding result because LS1 head porting wasn't quite a refined and dialed in in 2000 with the platform being pretty new.

 

I think they're 853 heads? Please see pic. Thanks

 

No, casting numbers are on top like this

 

No casting number, I am assuming the heads have been milled. Hope this helps. Thanks

 

it doesn't, lol. Ask who you got them from and let us know.

 

Like I said the motor was built in 2000. Gentleman that did my intake and everything, said they were factory heads that had been milled and hand ported and polished. There was a casting number there it has just been milled off. Thanks

 

Nobody mills heads on surface the OEM # is on, unless PO requested it because he wanted a stealth effect. Did you ever get this figured out? If they're 2000 OEM, probably reworked LS1 heads, as LS6 didn't come out until '01. You can find deals on 243 heads (LS6) on here sometimes. You're probably better off selling your heads, and going with AFR, Brodix, or Trickflow. If you must have OEM, nobody on the planet can port the LS1/241 heads to make the same flow/power that the ported 243 heads can. With that cam and ported 243 heads, you'll be closing in on 500whp. Call Tony Mamo. He's as good as, or better than, anyone. AFR used to make a "205" head, which is another step up, albeit not a lot better than ported LS6 castings. However, IIRC, the 205 heads have far superior low lift flow, which would help restore your lower rpm torque. Best of luck to you.......

 

So I ended up selling Bryce a custom cam that my goals were to greatly improve his driving manners.....make a bunch more low end torque, and not lose a bunch of power upstairs while doing so

Obviously that's not an easy task because to pick up the bottom end numbers and make it drive a bit better naturally your shrinking the size of the camshaft so you have to really nail the valve events in an effort to enhance the area your targeting the most improvement while trying to compromise the rest of the curve as little as possible. Its a very delicate balance

Most people already know that when it comes to camshaft design its ALWAYS a give and take.....make the top look better the bottom looks worse.....and visa versa

I was very please with the results and so was Bryce, the OP of this thread.....Im glad someone posted (Grinder11....thank you) as it was a reminder to update it with the results of our efforts.

Here is where he was with the original "small cam" versus the larger cam he installed.....while he was happy how it felt after 4000 RPM he said it felt really sluggish around town and at lower cruising RPM's wasn't as nice to drive. He lost alot of the punch in his typical driving

At anything with the exception of WOT the car felt alot lazier.....a small part of this is his ancient ported OEM castings from the early 2000's but at the end of the day Bryce shared with me he preferred the way the car drove when it only made 418 RWHP with the original smaller cam he removed

This is a copy of that original small cam to big cam dyno comparison that the first post included.....I just copied it here so you could better see the newest data from my cam selection versus the original two cams.




This is what the custom cam I recently spec'ed looked like against the larger cam that he decided he wanted to replace.....we gave up some peak power of course but much less than the original small cam and we made the most torque across the bottom and middle RPM's including the highest peak torque number of all three cams. Obviously the red curve below is the custom cam I just helped Bryce with



Big gains in peak torque across the usable "street" curve!

Looking at the numbers

Original small cam..... Peak HP 418 Peak TQ 419
Larger cam................Peak HP 477 Peak TQ 435
Mamo custom cam.... Peak HP 457 Peak TQ 451

Car drives better than it did with the first small cam.....lights the tires at will in any of the lower two gears (never did that with either of the other two cams) and the customer says the car feels faster with the smaller custom cam we just installed than it did with the big cam. The gains in "normal driving" is really the story here though.

You guys are looking at WOT gains only in the lower RPM when looking at dyno data.....the part throttle stuff is improved alot more than that but unless you have a load cell dyno to compare those types of things you can only use the buttmeter and the OP is super stoked with the results and how the car feels like its 500 pounds lighter now.

I was pleased with the results.....it was the target I was hoping to offer Bryce (big gains across 80% of the curve and not too much of a beating up top) but you never know the outcome till you know so there was anticipation heading into the test as you would expect.

Also, I strongly suggested he update and put a pair of my MMS 220 or MMS 227 heads on this engine and I could offer him huge gains everywhere......at the end of the day the weakest link in his combo is the 20 year old ported OEM castings

Im confident a set of my 220 or 227 heads with no other changes would put him low 500's at the tire and 480 ish RWTQ with no other changes.....the entire curve would have been dramatically lifted and the car would feel even better at part throttle but Bryce opted to hold off

I was disappointed as it would have been a really exciting 4th chapter but who knows.....he may revisit this chapter sometime down the road. We all know how addictive this hobby is!

Anyway....wanted to share the results with you guys as it shows how a properly chosen cam cam maximize your gains and minimize your losses

When it comes to cam design that's always the "threading the needle" I'm trying to accomplish....to maximize the results of my customer's build while still meeting their goals regarding drivability and the power curve in general



Catch you guys later

-Tony

 

Just goes to show a donkey d**k cam isn't always the best. I also bet the custom cam car would outrun the donkey d**k cam car since it has more usable power under the curve.

 

Unless your converter is loose enough to blow passed the lower RPMs and sling shot you into your powerband lol.... Like it should be......

 

Yes sir.....

Also this guy doesnt race his car.....I doubt he has ever taken it to a dragstrip. He mainly streets the cars and hated the huge loss in bottom and midrange power he suffered with the larger cam.

If you know how to drive a manual and left the line at 5K plus or had an auto with a big converter I think the larger cam would perform a touch better at the track but we are talking about a tenth or so if I had to guess

For a guy that doesnt really go to the track, this "tenth" is worthless and the tradeoff in how the car drives and behaves wasn't remotely worth that slight improvement in quarter mile performance.

I knew the larger cam was really all wrong for this customer when he told me flat out "Tony, I liked the car better when it made 418 HP" and the conviction in that statement on the phone was overwhelming......LOL

That's when I started discussing doing something smaller to get that low RPM performance back but spec'ing it differently so we wouldn't lose so much power up top.....maximize the gains....minimize the loss

Btw, the first "small" cam was a custom also....it just wasn't designed very well for a cathedral headed build and that's the one thing I knew I had working for me in this situation

This swap worked as good as I could have hoped or better but the bigger lesson not so obvious here is every customer has different goals and priorities with their build

While some folks might have felt the larger cam was great, for Bryce and how he uses the car it was just all wrong.


He is thinking about heads again.....we will see as that would truly be the have your cake and eat it to upgrade. It would just lift the power and torque curve a great deal everywhere (and provide even more throttle response and even better drivability)

Besides the short term pain in the wallet, a head swap on this car would be a grand slam homerun

-Tony