Spot on Sir ! chevynova man just gave a perfect example of his run. Had he not purged thru engine it set the stage of dumping tons of raw fuel in the cylinder washing it down..you know the rest. .. :shock:

I am glad Brian brought this up because EVERYONE it seems that doesn't know what they are doing ( me) assumes that you grenade a NOS motor by going lean.....YOU ALWAYS hear about maki g sure your fuel pump is up to snuff etc....the only thing that has held me up on running nitrous was ignorance....I have no experience with it and respect it enough to not risk my motor on it without having some sort of help.... My next one I am gonna try a small plate.

Bj looked at the vid and just wanted to ask do you like the hosier tires and have you run M/T and are you running 33/10.5-15w. I'm in need of new ones and looked at hosiers they have 33/10.5-15w reads that they are new tire with c11( Harder) compound. Thoughts if any on the two tires thanks.

Weighs 3100 me in it, older 10.5 car not that that matters.

Yes the M/T is the tire of choice. 33/10.5wx15 is the size tire on the car. Although I have run the same 60ft on both Hoosiers and M/T the M/T holds up longer on the overall performance of the side wall which is what goes 1st on these heavier 10.5 cars making good HP. Many of your top notch racers in this class like to get them off the car between 15 and 20 full power passes..Since M/T is the predominate tire in 10.5 racing I think Hoosier is trying to find a few more passes in their tires with the c-11 compound. I would recommend M/T. I also run tubes it provides for better stability with the heavier car running what they do. Many have other opinions on the tube or not to tube but I swear by it. Plus I have run faster all time ET with tubes on 15 inch American double bead lock wheels.
I got a killer deal on those Hoosiers in the vid. The guy we buy thru at the time was selling off the last of the 15 inch stuff. Everyone has gone to 16's

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Not sure if everybody knows that Nitrous Oxide systems changed the jetting chart not to long ago. The new charts have dropped the jetting on the fuel side of the plate. Make sure your using the new chart as I still see old charts on the net yet..

Thanks Bj. I have 31/10.5 15w and going to the 33s.

This is my input on nitrous is every engine is different as for the cams, comp,heads ect. The first thing is to get a good tune on motor and then work with what ever system your going to use following there guide lines.

You motor purge to get the air out of the fuel lines. The first motor purge is really weak. Usually by the 2nd purge the air bubble are gone. You line purge to get the pressure down. The nitrous is at 950-1050 depending on your tune. The fuel is at 4 1/2 to 5 1/2 depending on your tune. The lower the nitrous pressure the less pressure drop you have while going down the track. I go to the line as close to 1,000psi as I can, motor purge only what I have to make it have a crisp hit then line purge if I need to. You really shouldn't need to motor purge on your 2nd pass, but most people do just to make sure everything is working. I've also forgotten to turn on the 1/4 turn valve. It pruges like a turd pretty quick.
And you do need to motor purge every stage.
A street car that always has gas in the tank / fuel lines really want have air in the lines or need to motor purge. Almost all race cars / trucks drain the gas out after a race. I say drain out, but all I do is cut the fuel pump off, run the carb out of fuel then stick my drum pump in the fuel cell and get out what I can get out.


I've never seen an NOS jet guide, but i can tell you Speedtech's guide is WAY FAT and will burn your stuff up quick!! Theirs is only a 4 jet spread. I run a 10 jet spread, but every motor is different so you simply can't tell somebody they should run a 4,6,10 etc spread.

What I mean by jet spread is the difference between the nitrous jet and the fuel jet size. Example is 32 Nitrous jet and a 28 fuel jet. That's 4 jet spread.

Let me also tell you most people will LIE to you on their jet spread and hope you try it!!!!


That's true to a point.

It's really hard to run the car / truck on just a motor pass with such a tight converter and tall gear and get a good read on the plugs.
I changed the jets in my carb to lean it out. I went from 95 to 90's square which is too lean if I were to run on motor alone. Leaning out the carb is a huge debate that not everybody agrees with. Some will tell you to leave the carb alone and tune the nitrous / fuel, but most guys like me that have a dedicated nitrous motor (meaning I don't run without nitrous because of the really tight converter and tall gear) lean the carbs out a good bit.

I totally agree with your post for a car that runs nitrous some of the time and on motor some of the time.

Getting the timing correct and phasing the distributor are important things to do too.

Hotrod you have some GREAT people on here you can ask questions at Any time. Some have already weighed in. Another one on here is Zipper ( John Allen ) Zip has been running since the 60's that I know of..Zipper is a certified World NHRA recorded holder...He knows his stuff...

Rabbit I agree. My engine is all out nitrous too. I was going on that he was going to run motor and nitrous.

I pretty much run any where from 350 to 700 and like you and Bj check everything every pass. I watch guys at some of the grudge races run pass after pass and never check anything because they don't want anyone to see there engine. Then you got the guys that don't anything that wonder way the engine doesn't sound right after a pass and run it again wondering whats wrong. Bj said it best that there is 196 different things.

I sure learned alot about using spray there is a lot more to it than I thought. It a good thing I never sprayed my car sevral years ago when I concidered it. I would have had it all messed up and blew it up in a hurry.

thanks again guys like i said i put all the great info i get from you guys and use it!!

Just so you guys know small kits are simple and I mean really simple to use. If you have somebody that know a little about it nitrous is a lot of fun. It is the cheapest horse power you can buy!! The torque numbers it adds are insane. With a motor that's prepped for it it a lot of fun. Just don't jump into like I did! I went from a single stage 200 shot to 3 kits over 1,000hp of it and it didn't work out so well! lol

You said a mouth full there Rabbit 200 to 1,000. I also went from 200 to 600/700 BUT I had a tried and true set up and hands on experienced guy with me every pass. You can see him passenger side in the vid. I DO NOT go to track without him.

Also what you mentioned about TQ is 200% true...The TQ #S achieved with nitrous is un-real...

I've there and done that, but the one thing i've never, every run is Nitrous, i donot know didly squat about Nitrous, blown gas, blown alcohol, injected gas or alcohol i've been there, but i'm afraid to do Nitrous, because i donot know the limits.
I do know it's very easy to waste an engine on blown alcohol and i'm almost certain it's easier to waste one on Nitrous.

Zip.

I'm like Zipper . . Old School, I guess . . I've raced with both Blown and injected nitro, Blown and injected Alky, normally aspirated Gas and now, normally aspirated Alcohol (carburetor) but "I know Nooothing" about Nitrous.

And based on the color of the headers on the dragsters that're using it, don't want any part of it . . If the outside of the engine is that ugly, don't wanna see the inside!

Zip,

I would be willing to bet a big shot would show them to you in a hurry. :lol: :lol:

Curtis

I assure you the limits are found quick..I hope this thread gave a few some insight to a short cut.

I was also a Blower Guy LOOONG before I ran Nitrous..Both Alcohol Blown Injected..the small block was a 383ci the BB was a 572ci

you should have saw them when I drove those straight Zoomies into the show Hall that night..oooohhh my GAWD it was blowing HVAC DUCT WORK LOOSE....LMAO 8) 8) 8) 8)

One of the Local Journalist/Photographer loved my Old school theme Hot rod . This was mid 2000 long before the Rat Rod or reality shows got going...The guy was on to something and I blew him off..he wanted to film a day in a racers life with my 65 Nova..little did I know this could have been big...but who would have thought a REALITY SHOW ?????? so I never called him back .....Ohhh well !!! :shock:

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Cool pics BJ.

I'll add one more thing about nitrous. At some point you cross a line and into one side effect of nitrous. You will loose about the same amount of et on motor as you gain on nitrous.
In other words when you add a tall gear and tighter converter to handle the additional hp/ torque to gain an extra 2 tenths you'll loose 2 tenths on motor. Of course the amount you gain could be a lot more or less depending on the set up.

It's way worse for me and my application. I gained 1-2 tenths on nitrous from what I use to be able to run, but have lost 7-8 tenths on a motor pass. My motor want turn more than 5500 -5700 on motor alone and it takes FOREVER to do that. lol

to chime in with Rabbit on the lose of et motor vs. spray pass....My car has a pretty big 7/4 swap..don't have cam card in front of me but wanting to say its 116 or 118 lobe speration 100% Nitrous grind...the converter is soo tight there is NO FLASH what so ever bringing it up on the brake on a motor pass...My tires are 33 inches tall with about 102inch roll out..I run a 3.60 gear..so if you factor in the tire height you looking at 3.30-3.40 gear based on a 30 inch tall tire.

here we go....All motor Pass-ET 5.80'ish 1.32 60ft 126 mph
1 small hit 250-ET 4.92'ish 1.10 60ft 144 mph
2 stages 250/300- 4.68'ish 1.09 60 155 mph ish

see how she comes alive !...My headers are fender well exit but the sound change of the motor from motor to spray sounds totally different in a way I cannot explain...its just freakin mean.

Again Blowers were my first..I have drug the back bumper with my injected set up at 130mph.....but I have to be honest the sudden SHARP TQ curve from the Nitrous Hit is 200x off the chain then the flat TQ curve of the Alcohol injected.....Sort of like jumping in 20 degree water buck naked...YES it will take your breath like this if you have a Big enough shot being dumped in there at one time.....You know your moving when the traps at the end of the 1/8 mile have narrrowed up so much it looks like your trying to drive into a rabbit hole @ 150 mph.

just to show engine comparions

383ci BDS Stage 4 teflon blower,enderle Bird catcher dynoed 1320hp 1100ft lbs of TQ at 26psi sucking in bad air in dyno room.

572ci 1400 series littlefield blower enderle Birdcatcher, promag magneto 2200hp 1600ft lbs TQ

632CI Big Chief EPD fabricated sheet metal intake pair of reed 1200 carbs
engine dynoed by itself 1350..and remember its set up to run Nitrous....the advertised rating on the hp jets 1st stage 260hp 2nd stage 300hp ( probably low on the #'s) but for the sake of argument ad the proven 1350hp plus the rated NOS jets and you got 1910hp.......NOT A CLUE ON TQ....BUT I WILL SAY A BUNCH AT ONCE...


Last Time I said this there were a few that weighed in...First let me say a 60ft time is important in 1/8th and 1/4 mile racing....what I am saying today as I did a few years back is the 1/4 is little more forgiving if you bobble the 60ft, you can somewhat recover..ask any healthy turbo guy...but in the 1/8th mile if you don't pick them up and lay them down like a MADD man in the 60ft you will not have a ET run for Chit..

to prove my point look at my vid below.I left the line on 1 stage and let off.My wife was working the video from the traps..this was a a shake down run for me intentionally meaning to hit it hard at 60 ft and kill it.....I was lined up next to a 5.90et car....I came out hot on 1 gun laid down a 1.11 60ft and around 70ft I let out totally off the gas and costed thru the traps...I still ran like a 7.00et and coasted 2/3rd of the track...the 5.99 car finally caught me at the MPH cone..I was coasting maybe 60 mph by then.. you can hear me coming off the line ( My wife is telling my Daughter here he comes...lol) see me coasting when the 5.90 car just caught me at the end. turn up the volume ...lol


http://www.youtube.com/watch?v=jn0p3Og6d9o

The reason I bring this up is not to put my Nova on a pedestal...No this is common practice around here...most of your Quick cars run like this...all your Outlaw cars do..I use to shake my head when I would go to a Outlaw race and watch them shakedown doing 60ft full power hits shut the car off just past the 60 ft mark..I mean cut it off and coast thru the traps at 50mph with a 5.50et.

Point I am driving home in drag racing you much rather have a Quick car then a fast car...the example I gave you above explains it...I cannot tell you how many cars I have outran in the past pre-outlaw car days that had better MPH then me but I got there before they did....bottom line they were spinning...you can bet if My MPH is up my 60ft is down.

final point; As Rabbit said what you give up in motor you gain in Nos...you can't have the best of the best in both worlds...but you can build one that doesn't kill you either way and you can have decent power on motor and still pick up 3 tenths or so on spray..your engine guy ( if he is good) can help you with this.
As I type this part I am thinking of Logan .....What you would need out of spray is a car set up that could handle a Big shot NOS(250 hit) off the brake...thats hitting it with 250hp out of the hole...if you can get your car to handle this hit without spinning too bad you will only need that 250hit to stay on 1.5-2.0 seconds this will put you out over the 60 ft mark and on the way to a killer run in the 1/8th mile....In my world if I make up 2.2 tenths on the 60ft...I make up 9 tenths on the entire run...I have known people to activate their Nitrous down track...I personally do not recommend this.Hit it leaving the line while the chassis is naturally loading the Nos hit will help this process and help keep it loaded.....My car is more stable to drive under full Nos pass then motor pass... ...if My math is right here This is how I experience my 1/8th mile ride under full power after the 330ft. ...I am traveling approx 171ft per second from 330ft mark thru traps in 1/8th

whewwwwww..ok I am done...sorry so long guys hope someone gets something out of this..did not want the thread to die.

I wish we had so outlaw style racing around here there has not been in a long time. The local track that I run at just does not prep the track good enough to hold that kind of power it got to a point were every time there was a heads up race at least one would crash and people just stopped coming to participate.

ya swiley been there done that too many times...Thats were the gear retard timing ramp comes into play...winning a race is NOT always the fastest ET but rather who gets across the line 1st.....the track has to be good the entire length..