nitrous

15th January 2010, 23:17

i have a nos nitrous oxide kit sat in my garage doing bugger all i want to put it to some good use but its a 75hp shot and im afraid it will blow my engine to bits as my compression ratio is 16:1 can anyone help?

15th January 2010, 23:31

standard internals? if so i wouldnt reccomend 75bhp shots, ppl do and have done it but end of the day it wont be good for stock internals,

15th January 2010, 23:31

I think 75hp is the highest you can go on standard internals, i wouldn't still personally. As long as it's set up right and is used correctly and the engine is in good nick them it should be ok

15th January 2010, 23:34

what did you do to achieve that compression rate?

15th January 2010, 23:51

heavy valve springs skimmed the head as much as we could then skimmed the deck thick gasket cp pistons forged rods lightened the crank newmans cams we only stumbled across compression wen we had a fail to start upon fitting the engine and checked for compression and came out with 252 psi over each bore,exactly equal too was chuffed as fuck the problem was a dodgy crank sensor lol

15th January 2010, 23:54

and how did you work that to be 16:1

you can only take so much of the head before you lose you combustion chamber.

also if you have built an engine to that spec you would know what would be safe on it.

16th January 2010, 00:00

75 shot is ok on stock internals, using a progressive controller, wouldnt recomend without a controller, and at that comp ratio 75 shot will be putting it under a lot of pressure and something will go bang.

16th January 2010, 00:03

Quote:

Originally Posted by webby

and how did you work that to be 16:1

you can only take so much of the head before you lose you combustion chamber.

also if you have built an engine to that spec you would know what would be safe on it.

agree with evrything in this post....

16th January 2010, 00:04

and adz post, IMO though i wouldnt go with 75 on stock internals at all, but as said you havent,

16th January 2010, 00:57

not particularly true as u hit the valve seats before you really effect your combustion chamber. and i no nothing about nos so dont no how much it will effect high compression engines

16th January 2010, 01:05

so how did you work it to be 16:1 though?

16th January 2010, 01:07

well a rough approximation of engine test results

16th January 2010, 01:11

well whoses pistons did you use?

i know wossner s1600 pistons to raise it to about 13:1.

the pistons you bought should have told you what they raise cr to. so that should give you some idea.

16th January 2010, 01:14

most of the engine was built before i bought it but i was told they was cp

16th January 2010, 01:16

Quote:

Originally Posted by blackie_2k5

and adz post, IMO though i wouldnt go with 75 on stock internals at all, but as said you havent,

from past experiance, personaly now i wouldnt go above a 50 shot even with controller, on stock internals, but if its forged 75 to 100 would be ok, but its a bit of a shock to the engine without a progression.

16th January 2010, 01:24

you cant take cr from a compression test it involves cc'ing the combustion chamber and some complex maths and a formula i can never rember to get it right.

back to your origonal question i wouldn't reccomend a 75bhp shot on your engine without a controller.
adzvtr iirc has had first hand experience with a nitrous backfire running a 75 shot uncontrolled.

Edit: i am real slow at typing lol .

16th January 2010, 01:25

Quote:

Originally Posted by adzvtr

from past experiance, personaly now i wouldnt go above a 50 shot even with controller, on stock internals, but if its forged 75 to 100 would be ok, but its a bit of a shock to the engine without a progression.

totally agree, im thinking of getting nos kit when my cars all builtand running spot on etc, see what the little boosted 8v could do with a 75 shot, wouldnt go higher as even forged its still not good for your engine and i want it to loast, probs wouldnt even use it unless at shows etc but be handy to have

16th January 2010, 01:27

Quote:

Originally Posted by webby

you cant take cr from a compression test it involves cc'ing the combustion chamber and some complex maths and a formula i can never rember to get it right.

back to your origonal question i wouldn't reccomend a 75bhp shot on your engine without a controller.
adzvtr iirc has had first hand experience with a nitrous backfire running a 75 shot uncontrolled.

agree with this also, ideally need the stats from your pistons to help acertain what cr you have, how did you chose what size h/g to run without the details from pistons and head skim?

16th January 2010, 01:30

blackie im going to see if a mate want your psx kit in the morn

16th January 2010, 01:34

Quote:

Originally Posted by blackie_2k5

totally agree, im thinking of getting nos kit when my cars all builtand running spot on etc, see what the little boosted 8v could do with a 75 shot, wouldnt go higher as even forged its still not good for your engine and i want it to loast, probs wouldnt even use it unless at shows etc but be handy to have

im going boost by the end of year, once brakes and drive train are sorted, will be keeping the nitrous ona progressive with a 30 to 50 shot dependent on what she goes like on boost,
and shayne as webby said yes i know first hand what happens when using this stuff before i knew anything about it. to save problems and money later m8 research about it before anything.

16th January 2010, 01:39

i'd like to get my hands on a couple of empty nos tanks, i'm not brave enough to actually have it installed in my vts but i would like the empty tanks just for show as part of a boot install, any ideas of where to get a pair?

16th January 2010, 01:39

Quote:

Originally Posted by adzvtr

im going boost by the end of year, once brakes and drive train are sorted, will be keeping the nitrous ona progressive with a 30 to 50 shot dependent on what she goes like on boost,
and shayne as webby said yes i know first hand what happens when using this stuff before i knew anything about it. to save problems and money later m8 research about it before anything.

sounds good, dont think ive seen your thread yet mate? gonna have a look and read through tommorow

sounds like it will be an interesting read.

webby thats not a prob mate if he wants it just let me know

16th January 2010, 01:40

Quote:

Originally Posted by sqwidge

i'd like to get my hands on a couple of empty nos tanks, i'm not brave enough to actually have it installed in my vts but i would like the empty tanks just for show as part of a boot install, any ideas of where to get a pair?

if its just for show just get some old fire extinguishers and put a tap on and a nos sticker, dont see the point but each to their own mate

16th January 2010, 01:44

Quote:

Originally Posted by blackie_2k5

sounds good, dont think ive seen your thread yet mate? gonna have a look and read through tommorow

sounds like it will be an interesting read.

webby thats not a prob mate if he wants it just let me know

a fellow amazon green vt, will be taking a look at yous 2 m8, had a quick glimpse looks awsome. mines had many ups and downs lol.
squidge give lippy a pm, i know he has a bottle for sale, failing that listen to blackie its a good idea if its just for show.

16th January 2010, 01:48

Quote:

Originally Posted by adzvtr

im going boost by the end of year, once brakes and drive train are sorted, will be keeping the nitrous ona progressive with a 30 to 50 shot dependent on what she goes like on boost,
and shayne as webby said yes i know first hand what happens when using this stuff before i knew anything about it. to save problems and money later m8 research about it before anything.

You not think your cars bloody fast enough

Why not just get smaller jets? What nitrous kit is it?

75bhp without a progressive controller would be silly, you would torque steer off the road

16th January 2010, 01:49

be cheaper, i actually liked the car green alot but my ex keyed both sides so thought id go white when i spray it

cant wait to read yours like, cheers mines hopefully gonna get an update tommorrow weather prevailling *sleeps now for energy for said update haha

16th January 2010, 01:52

thats why i chose to ask around before touching it lol,i was under the understanding that dividing your compression by the atmospheric pressure you will obtain a rough over estimation of your compression ratio

242 psi divided by 14.2 = 16.9 ish

My local Evinrude certified master mechanic checked the cylinder pressure on my trusty old V6 Evinrude 225-HP and gave me the readings. The values were in pounds-per-square-inch or PSI, and the numbers were in the 90 to 95 range.
Atmospheric pressure, nominally 1-BAR, is about 14.5-PSI. So if I divide my cylinder pressure readings by 14.5, I ought to get the compression ratio:

90 / 14.5 = 6.2

This implies my engine has a compression ratio of 6.2:1.

16th January 2010, 01:55

Quote:

Originally Posted by DusheR

You not think your cars bloody fast enough

theres always room for improvement, and i have nothing else to waste my money on so why not waste on a saxo lol

Quote:

Originally Posted by blackie_2k5

be cheaper, i actually liked the car green alot but my ex keyed both sides so thought id go white when i spray it

cant wait to read yours like, cheers mines hopefully gonna get an update tommorrow weather prevailling *sleeps now for energy for said update haha

will have a gd read tomorrow, and look forward to the update, got a few of my own soon.

16th January 2010, 01:57

Quote:

Originally Posted by shayne_vtr

thats why i chose to ask around before touching it lol

best idea really, what nitrous kit do u have, as you can get different size jets for not much money.

16th January 2010, 02:00

you cannot work out compression ratio acurately without knowing the volume of the combustion chamber. it is too late for me to get out the books but of the top of my head its

cr= (pi/4)xbore^2xstroke+combustion chamber volume all over combustion chamber volume.

16th January 2010, 02:03

shayne i would like some info on the kevlar stuff you do too please. i want a cold air scoop moulding up so pm dude with some info

16th January 2010, 02:19

i got it free of a lad who had it on his k20 civic,i think its a universal single fogger kit for four cylinder engines, i was quite listening i heard do u want my old nos kit and the rest was images of fire and images of speed,(pros and cons)

16th January 2010, 02:21

This thread as made up my mind, bottle is being filled tomorrow