nitrous camshaft/converter question

[invegarating]

Hey guys,
I am new to this board but there seems to be some very good nitrous knowledge here,so here is my question,I am preparing my car to spray in the spring(i have not sprayed the car yet) and I am looking for a nitrous camshaft but what I'm wondering is do I look at camshafts for the stall of the converter off the nitrous or should I be looking for a camshaft with a starting rpm closer to the stall of the converter on the nitrous or something else?

Any help is appreciated
Jeff

[John_Heard]

Hi Jeff,

Welcome to Dragstuff - love the Vega..

How much you planning on spraying? What's the current combo?

[vegaracer]

Off topic but nice Vega

[invegarating]

Hey John,
Thanks for the props,the vega has a big shot plate on it that is jetted for 175 now but could go to 375/400 my chassis cert.is 8.50 and I dont really want to outrun that so I'm not sure what the total will be,the car has been a 9.90@127 lifting as the hood was coming off.

the current combo is:
406 sbc
Donovan aluminum block
AFR 227 eliminator heads
super vic/950 hp alcohol carb
powerglide-1.80 straight cut
10"tci ultimate street fighter,built for this combo
stall is 3700 on motor on brake-tci thinks 5000 on n2o
9'-33 spline,spool
this is a street car
current camshaft is 260/270@.050
.640/.659,106 lda
Im guessing the weight is 2900 with me in it
the nitrous is set up to come on when the transbrake releases,no controller currently and the ignition is a MSD 7al3
the ignition timing is set for street driving and I have never changed it at the track it is 10* initial and the dist. puts in 24* more by 2800 rpm but the dist.can be locked out (MSD)

Again thanks for any help,I would like to get this camshaft figuired out and installed.


Vegaracer,I have seen your car on cardomain,it is very nice,as a matter of fact a guy I know from another forum just got a 74 and he found a picture of a vega he wanted to model his after and it was your car!

Jeff

[John_Heard]

I'm not up to date on small block cams, maybe one of the other guys that are will chime in here.

I noticed you're using an alky carb, are you going to use a dual fuel setup (gas for the nitrous) setup or all alky?

[invegarating]

Hey guys,
I am not looking for a camshaft recommendation as much as an rpm recommendation,there seems to be some difference in opinion between camshaft manufacturers as to camming the engine for the flash stall when the nitrous hits,so I guess what im asking is would you cam it for the proposed flash stall or stay short of it?

The carb and the nitrous will both use methanol,fed by a single Aeromotive A-2000 pump

[vegaracer]

Vegaracer,I have seen your car on cardomain,it is very nice,as a matter of fact a guy I know from another forum just got a 74 and he found a picture of a vega he wanted to model his after and it was your car!

Definitley send me pictures of that when he's finished building it.
PM me if you want an e-mail address

Jamie

[572 BBC]

main thing is expect about an honest 1000 rpm maybe 1500 or so jump when the button is let out...i just cam corded my tach and on my brake(3500) with a 175 shot right off brake it jumps to 5000 instantly. i have a pretty tight 9" converter. i dont know much about small block cams,but my opinion is pick a cam that is best for motor only for applications of up to 250 shot.once u get into spraying more then pick a oversize cam to leave valves open a little more to get the extra nitrous and fuel into motor. ive talked to guys in my kinda world(bbc)and i kinda wished my cam was a tic smaller cause ill not push more than 275 nitrous hit thru my big shot.today on best motor pass went 9.74@144 nitrous pass netted 8.65@154 next year hoping to see low eights on a 275 shot good luck stay cautious and respect the power!!! oh by the way make sure u got all the ins and outs of bottle pressure,flowing psi on fuel side and other aspects

[invegarating]

thanks 572 bbc,
That is exactly what I was looking for,looks like you are a tenth or so quicker than me on motor but if the nitrous numbers work the same if I get around 8.60-8.80 that would be great,the 175 -200 shot would probably be all I'll use,at least until I build a 7.50 chassis for the vega ...thanks again for the help it is much appreciated

Jeff

[572 BBC]

hi jeff,i lost 1.1 second on my 175 shot compared to motor only pass.but my motor is 10 to one compression. i assume your 406 is 12 to one atleast to run 9s on motor. your converter is good id leave it alone for now.im guessing you may not quite loose 1.1 second on a 175 shot but close.....what im saying is nitrous makes a low cylinder pressured, non effecient motor more effiecent where as a big compression motor is already effiecent.

nos told me that on the dominator flange big shot plate the smallest nitrous hit recommended is 175(73 jet) if u have 4150 style idont know what is smallest recommended pill

are u aware of bottle pressure,colder plugs,better gas,timing and all the ins and outs?

[invegarating]

Yea,but I am wary of it,I also have a .073 jet but my fuel jet is 116 ...methanol.

My compression is 13.1 and I am using SCE titan copper head gaskets

my plugs are champion c59cx race plugs with the short ground strap(recommended by Jegs)

I am taking out 8* of timing at the hit(MSD 7al3 box)

I have a gauge at the bottle,but no heater

The converter was built for this combination with steel stator,extra clutches in the high clutch drum,vasco input shaft,1.80 4340 planetary

I tried to build the car to live through 1000 hp,but I dont think i'll need it

The one "variable" is,as this is a street car it has Hoosier quick time pro d.o.t. tires on it (29x14.4x15) but I think I can get them to work or at worst maybe make a little longer nitrous solenoid to plate line to soften the hit.


Hopefully at this point the only loose nut is behind the wheel


Jeff