waltsfastz

iTrader: (4)

With a healthy shot of spray? Was originally shooting for 12.5:1 but now thinking around 10.5-11:1. What do you all think?

hrcslam

Need a lot more information than this. What cam? Displacement? Intake (SP, Stock Ported, etc.)? Planned RPMs?

bowtienut

iTrader: (1)

There's no need to adjust your CR lower to accomodate nitrous.
...unless you're talking a 15:1 motor and a 500 shot

waltsfastz

iTrader: (4)

Thats kind of what I thought, Truth is I found a good deal on a set of pistions but they are 26cc dished. What is a good target SCR?
TEA heads, ported intake, no cam ground yet
BTW a healthy shot is 2-300ish

bowtienut

iTrader: (1)

For a weekend warrior track/street car, keeping it cool, and on pump gas, I'd target 12:1. You can push it higher, but your tuning window and safety margin disappear quickly.
For a daily driver, more like 11:1.

waltsfastz

iTrader: (4)

It is definatly not a daily driver, Or see much street for that matter. I guess i need to cc my heads again and do some refigureing

cardo0

The more juice u add the more room u have to make for it. Too much compression and too much juice will increase what they call pumping loses and power may even go down.
Plenty of info on setting up a NOx motor u just have to take the time to read it. If u add just a small plate sys then 11:1 ok but for a big 2 stage sys u would want more like 10:1. But ya gotta read for yourself because u want a nitrous cam to match - and u can rework your heads for dedicated nitrous also - and still run fine on the street also.

My 2 cents.

nitrous2fast

iTrader: (2)

nitrous LOVES compression. There are lots of medium shot(400-500) engines running in the 13-14:1 range. Don't let people fool you into thinking that the larger the shot the less compression you need.

bowtienut

iTrader: (1)

wow

waltsfastz

iTrader: (4)

OK thanks, What about on pump gas, Is 12.5 ish:1 still a good figure, Or can it be pushed higher without detination?

Rob94hawk

iTrader: (1)

What gas is readily available by you? We get 93 with 10% ethanol so high compression isn't an issue.

BIGsmokey10

iTrader: (3)

Watch out he knows his lt1s more then any one!

cardo0

Try this from Nitrous Supply w/s: https://www.nitroussupply.com/Tech.html

Q: Is there an ideal compression ratio?
A: There is a relationship between the compression ratio, nitrous flow, and cubic inches. At competitive levels of one nitrous horsepower per cubic inch and greater, compression ratio should be at least a couple of points of compression lower than a naturally aspirated combination.

Q: Can high compression engines utilize nitrous oxide?
A: Absolutely. High or low compression ratios can work quite suitably with nitrous oxide providing the proper balance of nitrous and fuel enrichment is maintained. NS kits are used in applications from relatively low compression stock type motors to Pro-Modified, which often exceed 15 to 1. Generally, the higher the compression ratio, the more ignition retard, as well as higher octane fuel, is required.


And this from Nitrous Express: http://www.nitrousexpress.com/carbfaq.html

Q. What is the best compression ratio to run with nitrous?
A. Nitrous can be run successfully with almost any compression, however we have found that 14-1 is the highest ratio that has a reasonable “Window of Safety”. Ratios as high as 17-1 can be used, but only by elite tuners with years of experience. Using alcohol as an enrichment fuel will allow you to run higher compression ratios without fear of detonation.

waltsfastz

iTrader: (4)

Good stuff, we have 93 octane here also

HellTeeOne

I've seen numerous street driven LT1 cars running 12:1 or higher compression and 200+hp of nitrous. With pump gas. People have literally been doing it ever since the LT1 motors came out.

No matter the SCR, it's always a decent idea to run some good gas when spraying, for the extra safety margin if nothing else. Not at all a requirement though, if the rest of your setup is up to the task.

That info on the nitrous companies' websites is highly generalized in nature and has little to no relevance in the LT1 world. Ignore them, actually from the couple of posts in this thread it appears you ought to ignore cardo0 altogether.

Nitrous is not the same thing as boost, you DO NOT have to lower your SCR to "make room" for it, nitrous bears it's own oxygen and acts as it's own intercooler so the combustion dynamic is very different than cramming a motor full of hot compressed air, as with forced induction. You just have to make sure your fuel system is bringing enough to the party and your components can handle the additional cylinder pressure. Running nitrous on a street car is not something for a guy who doesn't sweat details, pay attention and keep a regular eye on how everything is working.

cardo0

Yea sure pay attention to the details and then whats his name doesnt have any to share. Plenty of trolls on this site that hate any legitimate information rather than the accepted hearsay. Like the nitrous companies dont know what their trying to explain but he (or it) does. And u can take his word for it ha ha, ho ho, thats real funny. But u cant use his c.r. "recommendations" because he doesnt provide any. Easy to read who u should ignore.

bowtienut

iTrader: (1)

You should just pull that burr out of your *** so you can go back to sleep. You've made it clear that you lack any comprehension of this topic, yet continue to blabber on and cut and paste gross generalities, so YOUR calling out trolls and accusing anyone of not providing legitimate recommendations is simply preposterous.
You seem to be the only one who can't figure out who should be ignored
Whenever you decide to go see a shrink, just link him to this forum for a good background

HellTeeOne

The SCR recommendations you provided are absolutely useless and irrelevant to someone building or setting up an LT motor.

Have you ever ran nitrous on anything, let alone anything LT1 powered? Do you have any understanding at all of how nitrous oxide injection works and the combustion dynamic it creates? Are you at all familiar with the LT1 motor's ability to run much higher than typical SCRs on pump fuel to begin with, whether nitrous is involved or not?

Go ahead and build your 10:1 nitrous LT motor and then come teach everyone in here a lesson about heresay

But since you jumped on someone about not providing a recommendation on SCR for a nitrous LT motor that will see street duty, if it were me, I would shoot for something between in the range of 11.5 to 12.0. Where the exact # ended up would be dependent upon a number of other factors.

cardo0

So what are u basing your 11.5 to 12.0 comp ratio on? U have any real data to support it? Or just more hearsay. What size NOx shot? Oh, oh, thats right any size shot unhuh. Are they all the same to u?? Admit it u dont know! What are the sources of your information. Joe, Smoe and someone on the sidewalk? What are the "other factors" in choosing a c.r. - thats what the OP wants. So lets hear it. Ya, nitrous vendors cant touch that kind of help. In your nearly empty profile i see a student. I can imagine how much time and $$$ a student has to spend proving NOx compression ratios. Plenty of time to troll the forums though. Get a real life.

SS RRR

iTrader: (2)

These forums have been around for at least 15 years. Camaroz28.com has been around for 20 if you count the mailing list before they obtained a UBB, as well as local/regional boards many of us have been members of that are no longer around. There have been numerous people that have come and gone who've shared their setups, successful or not backed up with dyno and track results all over these forums. The two individuals you are talking **** to have also been around the block a few times, and then there's you, mouthing off using generalized statements and a stock car which you've done nothing to other than maybe an air foil...

Just a friendly reminder from my favorite moderator: