200-250 shot on 11.5:1 stock bottom end?
12-10-2010, 12:25 PM
#1
200-250 shot on 11.5:1 stock bottom end? STOCK BOTTOM END LQ9. 64cc heads on a .040 gasket. stand alone fuel with c16 and splitting the shot into 2 stages.
will a 200-250 be safe with a good tune? or should i step back on the gasket thickness to drop the compression some?
will a 200-250 be safe with a good tune? or should i step back on the gasket thickness to drop the compression some?
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12-11-2010, 11:02 AM
#8
The quench area is what you need to open up... .041 is real tight for a nitrous motor. A tight quench speeds up the burn rate ... open it up and it will open up the tuning window.
12-11-2010, 12:06 PM
#9
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Its very possible. Your tune has to be spot on.
Your LQ9 shortblock is pretty much the same as my LS2, block material being the main difference. My compression is a good bit higher than you are looking to run. Its in the 13:1 range and I spin the motor to 7700rpm. I know i'm on borrowed time. One mistake and there will be parts all over the track. To make it even worse, there is no tps or window switch, its all on a button. Man, I love my button!
Your LQ9 shortblock is pretty much the same as my LS2, block material being the main difference. My compression is a good bit higher than you are looking to run. Its in the 13:1 range and I spin the motor to 7700rpm. I know i'm on borrowed time. One mistake and there will be parts all over the track. To make it even worse, there is no tps or window switch, its all on a button. Man, I love my button!
12-11-2010, 01:22 PM
#10
Has nothing to do with the compression ratio, 11.0:1 is no problem... its even a little low for a nitrous motor.
The quench area is what you need to open up... .041 is real tight for a nitrous motor. A tight quench speeds up the burn rate ... open it up and it will open up the tuning window.
The quench area is what you need to open up... .041 is real tight for a nitrous motor. A tight quench speeds up the burn rate ... open it up and it will open up the tuning window.
all of the calculators that were around back then on tech have quit working, so now im stuck with online CR calculators that dont show quinch.
were stuck with the heads before it comes up. craig gallant is working his magic on them as we type
12-13-2010, 05:22 PM
#13
Its not the compression that is the problem, nothing wrong with compression and nitrous. Tuning will be the problem, spraying 250-300hp on stock bottom end IMO is all in the tune and reading plugs. Add in the weight of the truck the tuning window gets a little smaller.If your tuner doesnt do alot of bigger nitrous setups and isnt good at reading plugs then it wont last at 250.
12-15-2010, 12:35 PM
#14
Has nothing to do with the compression ratio, 11.0:1 is no problem... its even a little low for a nitrous motor.
The quench area is what you need to open up... .041 is real tight for a nitrous motor. A tight quench speeds up the burn rate ... open it up and it will open up the tuning window.
The quench area is what you need to open up... .041 is real tight for a nitrous motor. A tight quench speeds up the burn rate ... open it up and it will open up the tuning window.
also, is there a good calculator to figure out the quinch of a motor?
12-15-2010, 02:46 PM
#15
http://www.rbracing-rsr.com/squishcalc1.html
^^^^ is complicated. LOL!
Most LS stuff is flat top piston so you just need to know if you are at "0" deck then your quench will simply be the thickness of your head gasket.
Hopefully the pistons are .010 in the hole that will help you gain some.
We ran tight quench before we knew what we do now.
Try to get it into the .050's if you can.
^^^^ is complicated. LOL!
Most LS stuff is flat top piston so you just need to know if you are at "0" deck then your quench will simply be the thickness of your head gasket.
Hopefully the pistons are .010 in the hole that will help you gain some.
We ran tight quench before we knew what we do now.
Try to get it into the .050's if you can.
12-15-2010, 03:05 PM
#16
so a stock gasket would put me damn near .050 quinch with 11.0:1 compression. this is assuming the piston is +.005 to -.005 according to the deck.
from what ive read the OEM LS2 gasket is .053 compressed. then i can mill the heads a little to bump the compression if i wanted and not hurt anything...
from what ive read the OEM LS2 gasket is .053 compressed. then i can mill the heads a little to bump the compression if i wanted and not hurt anything...
01-07-2011, 11:32 AM
#18
We all know it's possible to get that type of setup to work with a great tune, however I don't think the word "safe" should be associated with a 200 - 250 shot on the stock bottom end. You have to pay to play and when you're playing with that type of hit on the stock bottom end odds are you'll eventually have to pay for the new motor.
01-07-2011, 11:41 PM
#19
I went through alot of N20 on a stock bottom end LQ9 with a 250 direct port. No problems and motor was 12.1:1 on pump 93 and Torco blend in the stand alone. Only thing that was touched was bearings were opened up and rings were opened as well... Tune has to be spot on as mentioned..
01-13-2011, 06:42 PM
#20
I couple years back I had a stock 03 SS silverado w/80k miles. I sprayed 150 off the line and another 100 in second gear. Had to pull a bunch of timing and kept the afr around 12.1 but lived through many many passes at the track. All this on pump gas. Like everyone else says the biggest factor is going to be the tune.
