speedtigger

iTrader: (16)

I think it must be said that a specialized nitrous cam will sacrifice N/A performance. When you start customizing the valve events for nitrous performance, you will be departing from ideal N/A performance. Otherwise, there would be no such thing as a nitrous specialty cam.

reddragon71

True, im leavimg towards cam 1 at the moment, It seems to have all my bases covered...but at the same time cam 2 seems more optimized for my single plane setup, im just worried about the lsa on it with the juice

speedtigger

iTrader: (16)

Hopefully one of the gurus you requested in your thread title will chime in. I have never ran enough nitrous to justify a custom nitrous grind. I could only regurgitate what I have read on the topic which is typically the big nitrous grinds open the exhaust valve sooner and widen the lobe center angle to reduce overlap. What the practical, real world valve event changes are, I would not attempt to specify.

reddragon71

Any more input on this? I think I might just go with cam 1

speedtigger

iTrader: (16)

I think the IVC on cam 1 is going to be much too late on an engine with a single plane.

TXsilverado

iTrader: (18)

choosing a "nitrous" grind with anything 300 or less is a waste of time. grab a great N/A cam with a bit of exhaust bias and run it.

theres a video on youtube somewhere where they tested 3 of comps "nitrous" cams against a N/A cam. all on the same motor on the same dyno.

the N/A cam made more power N/A, and it made more power on nitrous. i'm sure if you started throwing big shots at the cams, you would see the nitrous cams start to shine. although a 300 shot seems big around this forum, it's not a big shot at all in the big boy racing world. the reason for that is most cars on this forum are street cars or weekend warriors. not as many dedicated race cars, and it seems that everyone serious has gone the turbo route.

just my opinion

reddragon71

So after some calculations and heavy reading I have come up with some numbers and questiona...as far as valve events are concerned the 2 cams are pretty similar, but cam 2 has an IVO 9 degrees later and an IVC 7.5* sooner with only 1-3* differences in exhaust events...the biggest difference im seeing is overlap.
Cam 2 has 22.5* of over lap where cam 1 has 12* of overlap...its my understanding that with my setup the intake is really going to like the overlap but when im hitting it with 300 it wont be as efficent as cam 1...is the 10* difference in overlap going to hurt me enough on the jug to justify choosing the other cam or not? (As txsilverado suggested)

reddragon71

Had a 3rd cam spec'd for the setup and it came in right along the lines of what strokertA suggested, 243/254 .624/.615 114

opinions? Im stuck here

speedtigger

iTrader: (16)

How much advance?

JakeFusion

iTrader: (7)

Super Vic is going to like something closer to Cam #2 NA... but with the nitrous, 1 or 3 would be better.

reddragon71

0 advance on cam 3, the car needs to be at utmost performace on spray first and foremost, i just want somethjng that isnt going to completely kill power NA

speedtigger

iTrader: (16)

I just cant imagine somebody specifying a cam for a 347" motor with a single plane intake with an intake centerline on 114. Who spec'd these cams? Do they have any experience with single plane equipped LS motors?

reddragon71

The 114 spec was direct from comp...from further discussion with very educated 10.5 outlaw sources (guys spraying 500+) theyare all steering me away from the 109+5 cam due to its lack of lobe separation for the amount of spray

reddragon71

Im inclined to believe the theory behind it due to strokerTA's success with similar specs...I also can see a benefit from less low end power with applications to street racing and converter specs (can run a slightly looser stall) and the spray will make plenty of torque down low

speedtigger

iTrader: (16)

I think in general what racers try to achieve when designing their nitrous cams are reduced overlap so that less nitrous is lost out the exhaust and an earlier exhaust valve open to help blow down the cylinder and get all the heat out.

In addition to the above, I think that nitrous can allow you to run a later intake valve close as the torque from the nitrous makes up for the low rpm torque losses associated with a later intake valve close. The benefit of the later intake valve close is that, within limits, it can increase your high RPM power. The downside is that this particular change probably has the most effect on the loss of midrange N/A power. This is why some nitrous combos are absolute dogs on the motor.

So, while I understand you want maximum nitrous performance, if that is your sole consideration in your camshaft design, the car could be pretty lazy on the motor.

I won't venture to cite any specifications as I have no experience with large amounts of nitrous nor do I recall anyone else in particular who has done exactly what you are doing that I can draw from. Stroker T/A has been there and done that and to me, actual real world experience is king.

reddragon71

I spoke back with comp and he said to plan on advancing it about 4*

speedtigger

iTrader: (16)

So, now you have:

1. 234/246 .629"/.629" 114+2
2. 235/246 .62x"/.595" 109+6
3. 243/254 .624"/.615" 114+4

If that is not enough, there is another cam that you may consider. The EPS "Single Plane" cam:

236/248 .615"/.615" 108 LSA
http://www.engpwrsys.com/index.php?a...d&productId=12

You might give him a call and tell ask him what he would recommend for your nitrous application. I have an EPS cam in my car.

reddragon71

Yeah thats where im at, do you guys think cam 3 might be too big for the ci and head/valve capability? Ill get ahold of eps and get their view on it

onequiklx

im putting together a 346 with good heads and victor jr intake. Im running the trex v.2 cam thats .610/.615 242/248 and 110+2. I plan on spraying 150-200 on it. Cam being on a 108 will run great on motor and will def pickup on spray. I feel its a good medium for both configurations. If i ever go all out for spray ill have a custom cam ground for my application.

speedtigger

iTrader: (16)

What kind of pistons are you using?