Anybody have any recommendations for a good nitrous cam for a 305 TPI. The car has the mods in the sig, and I am planning on doing a cam swap to see what it nets me on some more juice. Sound is good too, but I don't want the cam to actually hurt the car on spray.

 

Stumped you all huh?

 

Car craft ( I think) tested "nitrous cams" and showed they didn't work as well as advertised. Granted this was on a ford 460, with a plate setup, but still. The loss during NA was pretty significant. There was only a hair of gain on the spray, but there was loss over most of the powerband.

The concept is good though, so maybe it will net your engine a good gain. A nitrous cam by definition has a long LSA, and a wide split, ie 10* or so, exhaust over intake. Look at comps nitrous cams in the 262 advertised range. A roller with 114* LSA and about 206/216 is about the range i'd be looking for.

 

i was told that a cam for a 305 tpi wouldnt give hardly any HP increase. is this right. unless you know of a good cam that would boost my HP a good bit.

 

Who told you that BS? Somehow 305 cubes and TPI induction means it doesn't respond to a decent camshaft??
If you're asking about an NA 305 TPI (not talking about using nitrous with it as well) then you're asking a completely different question, and you should start your own thread in the TPI forum.

 

Ok, I was thinking the same thing as well about losing too much on motor. I will do a little searching to find a good cam. BTW sonix, hows that true trac working for ya???

 

Not sure yet, haven't put the car back together yet. It snowed today so I'm not hurrying yet.

 

I did my own "nitrous cam" testing... the results were interesting. The cam was the only thing changed on the entire motor. Nitrous was a 150 shot...

Comp XE274 (230/236, 110LSA):
motor: 12.52 @ 108mph, 1.70 60ft
nitrous: 11.77 @ 115mph, 1.56 60ft

Comp NX274 (230/244, 113LSA)
motor: 12.69 @ 107mph, 1.79 60ft
nitrous: 11.62 @ 117mph, 2.0 60ft

At first glance one may think that I lost about a tenth on motor and gained about a tenth on nitrous... which, is true but with the nitrous cam my car made so much more power on the bottle that it stopped hooking. a .44 loss in 60ft yet it still ran a better time and mph. My guess is that if it hooked it would have been in the 11.30's or better.

A lot of race engine builders say not to even bother with nitrous specific cams until you're spraying like 250+HP of nitrous and I think it's safe to agree with that on a race motor. For a street car it gives you something to ponder though... a nitrous cam will typically be more street friendly than a comparable N/A cam. Might be a good trade off... more drivability, better gas mileage, easier to tune (typically), and overall be faster at the track (on nitrous)

 

Hmmm, good info IROCTPI, thanks!
That's about what I was thinking. Since you lose a smidge of power on NA, you either have to be spraying A LOT (size of shot) or very often, for it to be worthwhile. To each his own.
But very good test results, that's good stuff right there.

 

With my old 305tpi, I used the xe258, with a 110lsa and 206/212.

 

Did you have the stock heads in factory form LB9GTA?? What I mean is no machining what so ever to the heads. A few people are telling me that the lift is too much for factory LB9 heads. Did you use 1.6 roller rockers with it too?? I was planning on that same cam with 1.5 rockers but on a 112 lsa. Was the 110 lsa hard to tune or not a very good street cam. I dont want to have idling issues or surging.

 

Yes, I had stock heads. Never touched them.

I had 1.6 roller rockers.

The 110lsa was a little bit a rough idle. But I never burnt a new chip for it either. If I would've, it would have been alot better. I had to increase my idle to help correct the surging.