Which is a better match to stock engine/valvetrain with Hotshot genVI (3 in collector) to 2.5 inch side exit exhaust for road racing? Any recommendations on cam gear settings as well. This car will be used for NASA TT and PT.

I don't know that one is better. If possible, I would look at dyno plots for the cams and try to pick something that sacrifices the highest HP number for something that makes some good midrange tourque. In PTE, we are all bumping up against the max HP number for the HP/weight equation so you have to be careful about that.

What does your car currently make now with the S3's?

I'll let you know in about two weeks. Putting the car on the dyno as a baseline.

C3s are a better choice if you're gonna upgrade anyway. If you go either S5s or C3s, make sure to tighten those lobe centers up.

I forgot to mention that I use s5's. I think they make good HP over all but they struggle in the low end a bit. I end up using 2nd gear in some corners that I would prefer not to.

My last dyno was 155HP and I have to stay at or under 160HP with my current weight. I don't have cam gears.

You'll get some midrange back when you tighten the lobe centers. Makes it pull really well from about 4500-8000rpm.

Unfortunately, you'll lose a fair amount below 4500, but I don't think our car is ever below that RPM going full-tilt. Cool part is it'll really idle like a racecar. Our car sounds like its got a small block in it with a healthy cam, at least at idle... :D

Rock, when you say "tighten the lobe centers", do you mean to dial in the cams with a dial gauge and a solid lifter? Or does that mean to tune cams on a dyno? I'm not sure what you mean.

thanx

scott, he means with adjustable cam gears i think
Rock, when you say "tighten the lobe centers", do you mean to dial in the cams with a dial gauge and a solid lifter? Or does that mean to tune cams on a dyno? I'm not sure what you mean.

thanx

Yep. Adjustable cam gears. We've got ours at +5* intake, -5* exhaust.

Rock, did you do it on the dyno or did you just zero everything out with a degree wheel? If you used a degree wheel, what did you use for a lifter? Also what cam gears are you using? Is your head the stock height or has it been machined?

When I degreed my Web cams on my DSM the centers were about 8 deg off.

Speaking from experience, the S5s are great for road racing, but I would not use them with stock valvesprings. We scattered the valvetrain I think 3 times in one season with these cams on a stock valvetrain. They do make a ton of power though!

Rock, did you do it on the dyno or did you just zero everything out with a degree wheel? If you used a degree wheel, what did you use for a lifter? Also what cam gears are you using? Is your head the stock height or has it been machined?

When I degreed my Web cams on my DSM the centers were about 8 deg off.

Just ran the JWT cam gears. Utterly brainless to set up. Just match tooth # and hole # and you're set.

Speaking from experience, the S5s are great for road racing, but I would not use them with stock valvesprings. We scattered the valvetrain I think 3 times in one season with these cams on a stock valvetrain. They do make a ton of power though!

On the other hand, I'm running S5's on stock valvetrain and have been for over a year. Not that I track a ton, but it's seen about 6 track weekends with these cams. I observe a stock 7,500rpm limit, but I've had zero problems with them.

I wasn't overly impressed with the power out put, but maybe my motor is just getting tired. I would of gone with C3's if I had the budget for upgraded valvetrain.

wait how do you guys get a hold of S5 cams? all i see on the site are S4 and then the C series cams.

what kind of gains do you see with the S5's?

soory for these questions but i have only heard of these cams.

I bought them new off of someone on these forums, so I did not go through a vendor. I'm no help.

I bought them new off of someone on these forums, so I did not go through a vendor. I'm no help.

yea i searched and saw you came up on a good deal man, what kind of gains did you get with em? i was going with s4's only because i didn't see s5's on the jwt site, also why i want to know where you guys are getting em from?

I would call JWT and ask them. They are the manufacturer. Their site is a little confusing. They may have something if you have a chat with them.

thanks for the info man.

You'll get some midrange back when you tighten the lobe centers. Makes it pull really well from about 4500-8000rpm.

Unfortunately, you'll lose a fair amount below 4500, but I don't think our car is ever below that RPM going full-tilt. Cool part is it'll really idle like a racecar. Our car sounds like its got a small block in it with a healthy cam, at least at idle... :D

That must be sweet, 0.026" more lift and 10 deg more duration that my C2's. Really a true race cam, I bet that does sound great at idle.

I'd imagine peak whp has to be ~170 or so at least, given the C2's push into the 160's on 91 octane pump gas, or higher with a more aggressive top end tune.