turbo cam vs. nitrous cam: what if I run both power adders?

[malice10985]

I wrote the cam guide that is floating around in the archives of cyberspace in our seemingly infinite "search" menu. I know a little about cams, to say the least. This latest question has been busting my balls, though.

Theoretically, a nitrous cam has very long duration on the exhaust lobe to allow all of that superhot nasty gas to escape the engine without burning up the exhaust valves.

On the other hand, a turbo cam has very short exhaust duration to keep the very high exhaust backpressure from re-entering the cylinder after combustion.

The two cams are opposite. I Emailed Scott Cook, the owner of the 10 second GTP, and the frontman of Intense-Racing. He admitted that he had no idea what cam I should get, since I plan on using both turbo and nitrous.

My friends think I should get a full on turbo cam, since I will be boosted all the time, and I will only be spraying sometimes. I think that is a bad idea for the following reasons: while the engine will be great on boost alone, it will cause a lot of stress on the internals when I do spray nitrous at the track. I don't want to blow apart any pistons because there is insufficient exhaust flow and the ultra hot exhaust gas is stuck in the cylinder too long. I have already blown a motor on spray once, I am not doing it again.

If I get a nitrous cam, the engine will operate great on both power adders, but it will be placed under undue stress because the exhaust gas will constantly be flooding the cylinders during everyday driving.

Honda's get away with using both power adders because of VTEC. The exhaust opens sooner and for longer at high rpm, so spray can be used without burning up the pistons and ex. valves. I don't have VTEC, nor do I plan on getting it.

What do you guys think I should get?

[WickEdSix9838]

Run a straight pattern cam. That way you have less exhaust duration to keep the velocity up for the turbo but you still have more duration than a turbo cam for the nitrous.

[Razzer]

Just my opinion, get a cam that opens sooner like the honda one and also stays open a little longer than stock, probably the best for both worlds.

[1DangerousV6]

thats what im talkin bout [img]smile.gif[/img] ..i've been interested in a cam that will work with both boost (supercharged) and juice

[WickEdSix9838]

Originally posted by 1DangerousV6:
thats what im talkin bout [img]smile.gif[/img] ..i've been interested in a cam that will work with both boost (supercharged) and juice

nitrous and superchargers require pretty much the same style cam. More exhaust duration than a typical NA cam to get out the extra exhaust gases that are getting blown in. The reason a turbo needs less exhaust duration is to keep the velocity up in the exhaust ports to spool the turbo better.

[1DangerousV6]

hmmm..cool..cams favoring exhaust are the ones i have been looking at anyway [img]smile.gif[/img]

[Arctc Wolf]

run a dual pattern cam. same intake & exhaust with high lsa. this is a good balance between the intake-favoring turbo and the exhaust favoring nitrous designs.

[malice10985]

By dual pattern, do you mean that the intake and exhaust specs are the same?

example:

int. ex.
.555 .555
240* 240*

If I am not mistaken, those are usually good NA cams. I think that would be the best, because it will mix the best (and possibly worst) attributes of each cam style.

THe guys at INtense gave me the # for CaMotion. They design cams for a lot of companies. I think they make TSP's cams, as well as intense. I will call them tommorrow and see what the experts tell me.

[Pewter2K1]

I am very happy with my cam selection...
210/220/ .512/.512 115LS Its an off the shelf from comp cam catalog. says boost/nitrous cam. I ran nitrous with it, picked up 1.3 seconds with a "100 shot" i use the "" because i had only like 900 psi in the bottle, and i was running rich like a MOFO.. but just on motor i picked up 40 hp without a lick of tuning, stock HP was 171,cammed was 222. Torque was about the same, gained only about 10. makes torque from around 2500 and carries flat til about 5200, hp comes in around 3000 and has a steady but flat raise to 5500, when my speed limiter kicked in, but the line was still climbing, so there was at least another 5-10 still in it till at least 6200.
has a decent lope at idle, but i could care less what it sounds like, as long as it makes the power.

[T-Punk]

the reason (from my understanding) a turbo like little overlap is because of the backpressure added by the turbo. Since a supercharger doesnt add backpressure its fine for the intake and exhaust valves to be open at the same time longer. Honestly i dont think a dual power adder is the way to go if you are going turbo. You would be better off with a second setting on the wastegate to increase too at the track. a better investment than the nitrous would be pnp heads and intake and possibly a thicker head gasket to give you a lower cr to run more boost. this makes your cam desicion much easier and you car will be happier than if you get a cam that kinda works with both systems. now if you just run a small 25-30 shot you will get a little extra power from the nitrous but what it will really help most with is to add an intercooling effect for the heated charged air from the turbo. another option is to use the nitrous to spray the intercooler to lower its temp to offer better heat exchange.

[1DangerousV6]

Originally posted by Pewter2K1:
I am very happy with my cam selection...
210/220/ .512/.512 115LS Its an off the shelf from comp cam catalog. says boost/nitrous cam. I ran nitrous with it, picked up 1.3 seconds with a "100 shot" i use the "" because i had only like 900 psi in the bottle, and i was running rich like a MOFO.. but just on motor i picked up 40 hp without a lick of tuning, stock HP was 171,cammed was 222. Torque was about the same, gained only about 10. makes torque from around 2500 and carries flat til about 5200, hp comes in around 3000 and has a steady but flat raise to 5500, when my speed limiter kicked in, but the line was still climbing, so there was at least another 5-10 still in it till at least 6200.
has a decent lope at idle, but i could care less what it sounds like, as long as it makes the power.

this is one of the ones i was looking at..i really like those numbers (both cam specs and HP/ET gain)

[WickEdSix9838]

Originally posted by malice10985:
By dual pattern, do you mean that the intake and exhaust specs are the same?

example:

int. ex.
.555 .555
240* 240*

If I am not mistaken, those are usually good NA cams. I think that would be the best, because it will mix the best (and possibly worst) attributes of each cam style.

THe guys at INtense gave me the # for CaMotion. They design cams for a lot of companies. I think they make TSP's cams, as well as intense. I will call them tommorrow and see what the experts tell me.

I wouldn't suggest just calling their tech line and having them spec a cam out. I've seen too many times where people have done that and they end up getting cams that are so screwed up that they never have a chance to run.

[malice10985]

Originally posted by T-Punk:
the reason (from my understanding) a turbo like little overlap is because of the backpressure added by the turbo. Since a supercharger doesnt add backpressure its fine for the intake and exhaust valves to be open at the same time longer. Honestly i dont think a dual power adder is the way to go if you are going turbo. You would be better off with a second setting on the wastegate to increase too at the track. a better investment than the nitrous would be pnp heads and intake and possibly a thicker head gasket to give you a lower cr to run more boost. this makes your cam desicion much easier and you car will be happier than if you get a cam that kinda works with both systems. now if you just run a small 25-30 shot you will get a little extra power from the nitrous but what it will really help most with is to add an intercooling effect for the heated charged air from the turbo. another option is to use the nitrous to spray the intercooler to lower its temp to offer better heat exchange.

-I already have a complete nitrous kit
-I already have thicker head gaskets
-I already have a forged, balanced and blueprinted bottom end.
-I have a boost controller so I can turn up the boost when at the track.
-INtense stage III CNC ported heads are being shipped as we speak. (wickedsix- I know we talked about abbott heads, but Intense made me an offer I couldn't refuse.)

CaMotion said that the Intense Stage III turbo cam would be the way to go for me. Since I am only spraying at at the track sometimes, it will suffice, and I should be happy with the results.

THey suggested that I get a massive dual pattern cam if I were trailering the car to the track, only making boosted and sprayed runs, and trailering the car home.

I want to run SCCA autocross as well as drags, so the turbo cam will be fine.

[12secondv6]

Ok.... why not just get a turbo cam... up the boost.... and use the nitrous as an Nter chiller style set up and spray the intercooler?

Focus on one power adder...... and use the nitrous to compliment it.....

Keep in mind... for me to say... don't use nitrous.... as a dedicated power adder.... ESPES over a silly turbo.....that should mean something [img]tongue.gif[/img]

Please... keep us updated!

[1DangerousV6]

^ yeah..NX has that intercooler fitting now specifically made to spray intercoolers..that would be sweet [img]smile.gif[/img]