Advise on cam

[Sniper]

What would be the best recommendation on cam spec for a ported heads/cam Gen V Viper?
I’d like a nice lope with good drivability.
And does having more lope affect the HP?

[01sapphirebob]

Scot or Dick Winkles at Prefix would be the ones to ask on that. At least a good starting point. :)

[Sniper]

I’ve already got a shop but was seeing what others went with for the best setup.

[sparkrn]

Scot or Dick Winkles at Prefix would be the ones to ask on that. At least a good starting point. :)

Sniper is not listening!

[Sniper]

sparkrn is not listening!
As stated, I’ve already got a shop who makes their own cams. I am asking what anyone else went with to give me an idea of what I’d like to go with.
The shop already knows what they are going to put in it but I’d like a little more aggressive cam if anyone has any insight.

There’s wisdom in a multitude of counselors.

[Steve M]

Read this: https://www.motortrend.com/how-to/camshaft-shootout-lobe-separation-angle-tested-explained/

My advice: if the car is being tuned with HPTuners, I'd go with something that the shop knows is tried and true. In other words, something they know they can reasonably tune given HPTuners' limitations with the Gen 5 PCM.

If you want to go with a donkey dick cam for the lope, you might quickly find the limits of what HPTuners can do, and you'll be left with a car that doesn't have good drivability around town.

Or maybe that doesn't matter. In that case, shove in the largest cam you can find, wait until the valves start smacking the pistons, back it off a couple of degrees, and call it a day.

[Sniper]

Good advise, thanks!
I was hoping someone has done a little more aggressive cam and could give some sound advise on the spec.

[13COBRA]

Stick to what Justin recommends.

[Dan Cragin]

This is tricky stuff on the Gen 4-5 cars, I had a big learning curve going in, back in the day when these cars were new. If you are going with a a non VVT single profile cam, getting the cam, lifter and valve spring package matched is critical.
Tuning is the next biggest issue. If you want the motor to last and drive right, tune on the rich side with a safe timing curve. Tune for street gas unless its a race car. HP is very limited on tuning.

There are some really great profiles for cams, if you want to see what makes big power, look at the Drag Pack V10 cams used by Dodge, they made huge torque and hp, but the are hard on the valve train.

I have seen so many cars go like stink, only to end up with another big rebuild after a good run. Just make sure you can afford that.

[Sniper]

Ok, thanks for all the info!
Sounds like I’ll stick with what the shop is already familiar with.
I was hoping to get a little more aggressive sound but I’d rather have a reliable motor.

[Steve M]

Ok, thanks for all the info!
Sounds like I’ll stick with what the shop is already familiar with.
I was hoping to get a little more aggressive sound but I’d rather have a reliable motor.

Define reliable. Or better yet, have the shop define it.

At a minimum, you'll need to check your valve springs on a regular basis. How many miles is that? The shop hopefully knows.

As Dan Cragin alluded to, the cam/valve springs/lifters all have to work together. How much durability testing have they done to make sure the components they are using are the right ones?

Even Prefix has had issues.

[Sniper]

Well, this is all new to me. Maybe someone can explain this.
I thought doing a heads/cam would be like having the normal motor with upgraded parts.
I’ve never had a heads/cam car.

[Mikey]

I THINK calvo uses an aggressive cam, give him a call or email

[StrokerAce]

With the displacement I would think these engines would eat a 230/240 duration cam with ease. Would something like that with say .61x lift intake and exhaust on a 115 LSA be considered lopey and hard to tune?

[Aevus]

Good advise, thanks!
I was hoping someone has done a little more aggressive cam and could give some sound advise on the spec.

I did a very aggressive cam on my gen 3 (248/256 @ 0.050'', LSA 114, .554/.603 lift) and you sure play with fire doing so, especially with a gen5 I would think...

You really have to need/want it, and have everything to match it (high compression + stellar full exhaust system + all upgraded valvetrain, etc...) and most importantly a really good tuner who will spend enough time to dyno tune it.

[Aevus]

With the displacement I would think these engines would eat a 230/240 duration cam with ease. Would something like that with say .61x lift intake and exhaust on a 115 LSA be considered lopey and hard to tune?

Less than 20 deg overlap you're in the ''safe zone'' in regards of tuneable...

230/240 115LSA is 5 deg so it's fine. Actually pretty moderate.

[Aevus]

This is tricky stuff on the Gen 4-5 cars, I had a big learning curve going in, back in the day when these cars were new. If you are going with a a non VVT single profile cam, getting the cam, lifter and valve spring package matched is critical.
Tuning is the next biggest issue. If you want the motor to last and drive right, tune on the rich side with a safe timing curve. Tune for street gas unless its a race car. HP is very limited on tuning.

There are some really great profiles for cams, if you want to see what makes big power, look at the Drag Pack V10 cams used by Dodge, they made huge torque and hp, but the are hard on the valve train.

I have seen so many cars go like stink, only to end up with another big rebuild after a good run. Just make sure you can afford that.


What Dan says.

[Lawineer]

How reliable?
How drivable?
How much lope?

Lope definitely affects HP. It's mainly two factors: How long the valves stay open ("duration") and mostly how much the intake and exhaust overlap ("overlap"). The more duration, the longer the valve remains open, the more power you can make at high rpm. More overlap also allows for more exhaust savaging at higher RPM. At 7000 RPM, X degrees of overlap or valve opening (or any valve event) is a lot less seconds than X degrees at 3000rpm. That's (one of the many) reasons an engine will run out of breath at high RPM.

Cam selection is exceptionally complicated, and it also depends on the rest of your setup and what you are willing to do. That's everything from intake manifold to gearing to FI/NA to the headers and catback. It's really not like picking an exhaust system. It's like 4D chess board with a million factors playing push and pull. I would strongly recommend following your engine builder's advice. If you think you can do better or improve upon your engine builder's recommendation, I would suggest you find a different engine builder. This is coming from someone who took masters level engineering courses in ICE and worked in motorsports.

[Aevus]

It's like 4D chess board with a million factors playing push and pull. I would strongly recommend following your engine builder's advice. If you think you can do better or improve upon your engine builder's recommendation, I would suggest you find a different engine builder.

Pretty much. Lawineer and Dan are right: it's not just a component it's a recipe, you need to carefully match everything.

I think I watched that video 3 times (and part 2) just to really get the basics in my brains...

https://youtu.be/JPAeepqrY-0?t=98

Then you need to think about the valvetrain, the flow numbers of your heads, compression, etc...

If you're doing an ''aggressive cam'' for the fun of the project (like I did), fine.
But if you just want to turn the key and have a driveable car without headache, don't go too far and/or trust entirely your engine builder.

[Sniper]

Ok, that video really helped me understand the bigger picture.
I keep seeing these videos of Vipers with an awesome lope sound and me not knowing how you get there and wanting to get there started asking what cam should I get to get this sound.

[Arizona Vipers]

Just tell Scot Rickord at Prefix that you want the one I run- https://www.instagram.com/p/CjVr4JOgvKG/
LOL

[Sniper]

I would definitely want that sound
But I’m not going with Prefix, way too much money for just a heads cam.

[13COBRA]

Just tell Scot Rickord at Prefix that you want the one I run- https://www.instagram.com/p/CjVr4JOgvKG/
LOL

Are you going to Rendezvous next year?

[Arizona Vipers]

I would definitely want that sound
But I’m not going with Prefix, way too much money for just a heads cam.

All the companies doing heads/cam are about the same cost.

[Arizona Vipers]

Are you going to Rendezvous next year?

I always plan on it! But won't know for certain until it gets closer to the event, glad to see you joined up!

[Sniper]

Actually, I’ve got a shop that will do heads/cam for a lot better cost.
And they’ve been doing Vipers since the Gen 1 came out.

[Nth Moto]

Actually, I’ve got a shop that will do heads/cam for a lot better cost.
And they’ve been doing Vipers since the Gen 1 came out.

With all due respect, it better be less cost if you as the customer have to be out asking the general public what camshaft profile you should be running instead of them. They should be educating you on the pros/cons of each and have the data behind those specifications for accurate realizations of the end product. And it's possible they do, and if so, you should be listening to them.

On the topic of cost, if it's an apples to apples comparison (IE, same included components as "standard", same general processes being done) the only cost variance can be the shop labor rate and amortization of development cost required to get to their end product. I can tell you that we completely revised our cylinder head program which cost some significant dollars in development and testing which netted us 30 WTQ gains in the midrange and very little at peak power, so while the customer may not see it on the dyno (because most only look at peak) you sure can tell when driving it. That's what those costs have the chance to gain you - and in no way does that make one right or wrong; that's up to you and how you value your investment.

[Sniper]

Yes, you are correct. I think everyone mistaken me asking about specs of cam for the shop not knowing. They already let me know everything will be based off my car once they get it, no two cars are alike. I was just asking about a lopier cam because I like the sound better. I am not giving the shop any info to go off of. Only what I’d like and they’re putting it all together.

And if I thought over $20000 is a bargain, I wouldn’t have shopped around.

[Arizona Vipers]

with all due respect, it better be less cost if you as the customer have to be out asking the general public what camshaft profile you should be running instead of them. They should be educating you on the pros/cons of each and have the data behind those specifications for accurate realizations of the end product. And it's possible they do, and if so, you should be listening to them.

On the topic of cost, if it's an apples to apples comparison (ie, same included components as "standard", same general processes being done) the only cost variance can be the shop labor rate and amortization of development cost required to get to their end product. I can tell you that we completely revised our cylinder head program which cost some significant dollars in development and testing which netted us 30 wtq gains in the midrange and very little at peak power, so while the customer may not see it on the dyno (because most only look at peak) you sure can tell when driving it. That's what those costs have the chance to gain you - and in no way does that make one right or wrong; that's up to you and how you value your investment.

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