compression for nitrous
Alot will depend on what you want to run for fuel n/a, if you're willing to run good fuel all the time then I'd go somewhere in the 13 to 1 to 14 to 1 range.
fwiw my 402 is 13.5 to 1 and @ 3500 lbs runs 10.5 on motor, 9.77 on a 100 shot, 9.61 on a 150 with a worse 60 foot time.
Motor was built for a 350 hit, which I'll never push it to.
fwiw my 402 is 13.5 to 1 and @ 3500 lbs runs 10.5 on motor, 9.77 on a 100 shot, 9.61 on a 150 with a worse 60 foot time.
Motor was built for a 350 hit, which I'll never push it to.
Thread Starter
Teching In
Joined: Nov 2007
Posts: 20
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wow i was wanting more of a pump gas car something like 11.5.1 but had people telling that it was to much compression that you need to have low compression for nitrous
also had texas speed telling me that nitrous loves compression is that true
also had texas speed telling me that nitrous loves compression is that true
Last edited by DTRtransam02; Dec 1, 2007 at 03:37 PM.
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Verdad Gallardo If you want to run nothing but pump gas, I would build a 10.5 to 1 motor and not even consider more then a 200 shot.
Race fuel, just makes things a TON easier, if you don't mind running a 118nos fuel in a standalone, I'd go 11.5 to 1 and keep it under 200 still, but I air on the side of caution.
There's people that have sprayed WAY more then that on more compression, but again I air on the side of caution.
I can tell you, my 13.5 to 1 went from 10.5 n/a to 9.77 and picked up a solid 10 mph on a 100 shot, and went 9.63@139 with a tenth slower 60 foot time (meaning I'm at the limit of my current suspension/tire setup) so the higher compression certainly liked the nitrous, that is for sure.
Alot of it depends on what your final goal is, if it's a 300 shot with pump gas, you're gonna be back to a 10 to 1 compression motor, so doing any serious n/a speeds @ the track are gonna get alot harder at that point.
Race fuel, just makes things a TON easier, if you don't mind running a 118nos fuel in a standalone, I'd go 11.5 to 1 and keep it under 200 still, but I air on the side of caution.
There's people that have sprayed WAY more then that on more compression, but again I air on the side of caution.
I can tell you, my 13.5 to 1 went from 10.5 n/a to 9.77 and picked up a solid 10 mph on a 100 shot, and went 9.63@139 with a tenth slower 60 foot time (meaning I'm at the limit of my current suspension/tire setup) so the higher compression certainly liked the nitrous, that is for sure.
Alot of it depends on what your final goal is, if it's a 300 shot with pump gas, you're gonna be back to a 10 to 1 compression motor, so doing any serious n/a speeds @ the track are gonna get alot harder at that point.
Staging Lane
Joined: Aug 2007
Posts: 95
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I run 11.5:1 comp, 110 gas ON and OFF the bottle. it idles like **** with 93.... im guessing thats probably not a good thing then. eh, whatever, its a carbed 383 and tuned for 110 so i guess it would idle hard on pump
200 is alot to start with, I'd put the timing and whatnot where you think you need it for the 200 you're planning on running, and jet for 100 and make a run... better safe then sorry. If all looks good, put it to 150, go again, all looks good then go to 200.
Just tossing 200 in there is asking to have a problem, unless you already have a baseline to go off of with the car that you know 100% to be good.
Just tossing 200 in there is asking to have a problem, unless you already have a baseline to go off of with the car that you know 100% to be good.
Thread Starter
Teching In
Joined: Nov 2007
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i already have a 408 with a texas giant cam and afr 225 heads 72cc with 11.5.1 compression with all forged internals for a three hundred shot all day every day but was worried bout the compression cause had other people tell me i had to much compression for nitrous so not to be rude bro i would rather ask ?s before i blow a 8 thousand dollar motor up
On The Tree
Joined: Nov 2007
Posts: 104
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I know it's not an LS1, but it may help a little. We have a pat musi built 11:1 406 in our 3rd gen race car. We are finishing up a few last minute things, then when the season rolls around we are going to wack it with a 350 shot. Once the chassis is set up and all is fine we will use both stages giving us 500-550 shot. It's not the compression ratio, it is all about the fuel and tune. Do lots of plug chops and keep tuning.