F/I and crappy 1/8 mile times
10-11-2007, 09:45 PM
#1
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F/I and crappy 1/8 mile times ok here's the low down. I'm from the DFW area and due to lack good 1/4 mile tracks around here the rage is 1/8 mile. lots of low 6 sec nitrous fbodys cars and and a handful of 5 sec 1/8 mile Fbodys....
my old setup was a forged H/C 346 w/ 300 worth of bottle through a 6 speed.
car went 6.3X @ 106 w/ a 1.40 60ft.
suspension was LCA, Wolfe Sway Bar, Subframes, TA and bilstein shocks.
now here's the deal. i've been building a 408ci w/ a GT47-88.
i see all these FI cars running 9's in the 1/4 but when i ask their 1/8 and 60 fts they are worse then my nitrous times...
Sooooo...my question. What's it take to get the low end grunt of a nitrous motor??? obviously FI back halfs better then a nitrous car, but why is it so hard to get the 1/8 mile times down?
i know there's a certain member going from a Nitrous setup to a 408 w/ a F1R and he's got the same concern i do!
my old setup was a forged H/C 346 w/ 300 worth of bottle through a 6 speed.
car went 6.3X @ 106 w/ a 1.40 60ft.
suspension was LCA, Wolfe Sway Bar, Subframes, TA and bilstein shocks.
now here's the deal. i've been building a 408ci w/ a GT47-88.
i see all these FI cars running 9's in the 1/4 but when i ask their 1/8 and 60 fts they are worse then my nitrous times...
Sooooo...my question. What's it take to get the low end grunt of a nitrous motor??? obviously FI back halfs better then a nitrous car, but why is it so hard to get the 1/8 mile times down?
i know there's a certain member going from a Nitrous setup to a 408 w/ a F1R and he's got the same concern i do!
10-11-2007, 10:12 PM
#2
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you need the proper AUTO with a sticky tire. a 6sp is not going to get you there in the 1/8th with a turbo. a two step will help, but its never going to be like a built cam/spray car.
the back half is totally worth it though
the back half is totally worth it though
10-12-2007, 02:24 AM
#3
why is it hard to get a nitrous car to backhalf like a turbo car? 
nitrous is there at any rpms just waiting behind a solenoid. Boost is waiting on rpms...load etc and there pretty much lies the reason it takes more work to get a FI car moving. If you look at folks like KP, it shows it can be done....most of us just dont know how or havent bought the parts to do it for whatever reasons.
nitrous is there at any rpms just waiting behind a solenoid. Boost is waiting on rpms...load etc and there pretty much lies the reason it takes more work to get a FI car moving. If you look at folks like KP, it shows it can be done....most of us just dont know how or havent bought the parts to do it for whatever reasons.
10-12-2007, 05:51 AM
#5
if you take a lesson from the turbo Buick guys, the best way to get your car to 1/8 correctly is to run an auto, upgrade your rear brakes as much as possible, and get the boost up on the line. there are guys over there pushing 12+ psi off the line, carrying the tires halfway through the 1/8 
10-12-2007, 06:24 AM
#6
[QUOTE=cablebandit;7934116]why is it hard to get a nitrous car to backhalf like a turbo car?
it takes more work to get a FI car moving. If you look at folks like KP, it shows it can be done....
True, You need the correct combo. My LT1 with a supercharger has Instant boost right off idle, no Lag, no delays, It kicks in just as fast as a nitrous car, and has a top end charge that wont quit!
it takes more work to get a FI car moving. If you look at folks like KP, it shows it can be done....
True, You need the correct combo. My LT1 with a supercharger has Instant boost right off idle, no Lag, no delays, It kicks in just as fast as a nitrous car, and has a top end charge that wont quit!
10-12-2007, 07:08 AM
#7
#1 if a turbo is matched up correctly, i.e. research, then the car can leave off the line quite fine.
THe main issue is your running at a 1/8mile track, I would set up a car so differently it wouldnt even be funny, 4.56 gears with out eevn thinking about it, 3 speed th3500, light weight and n2o all the way but that same set up would run out of steam in the 1/4.
Your building a car based on how you race.
Heck there are people out there with any track, they race from rolls. Now I wouldnt put a higly stalled th400 out for that race, id runa t-56....
THe main issue is your running at a 1/8mile track, I would set up a car so differently it wouldnt even be funny, 4.56 gears with out eevn thinking about it, 3 speed th3500, light weight and n2o all the way but that same set up would run out of steam in the 1/4.
Your building a car based on how you race.
Heck there are people out there with any track, they race from rolls. Now I wouldnt put a higly stalled th400 out for that race, id runa t-56....
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10-12-2007, 08:14 AM
#8
you could simply leave on a 150 shot or so and have a rpm switch from 2500-4500(till you reach full/almost full boost)
nitrous cars normally leave hard because of the big hits and you can make that tq any rpm you want...a transbraked auto should fix that in your car though
nitrous cars normally leave hard because of the big hits and you can make that tq any rpm you want...a transbraked auto should fix that in your car though
10-12-2007, 10:23 AM
#9
Centrif. S/C - 1krpm (1psi), 2krpm (2psi), 3krpm (3psi), 4krpm (4psi), 5krpm (5psi), 6krpm (6psi)
Turbo - 1krpm (0psi), 2krpm (2psi), 3krpm (6psi), 4krpm (6psi), 5krpm (6psi), 6krpm (6psi)
in reality with a properly sized turbo... it make full boost sooner. S/C guys say they have better off idle response because of the S/C... well thats fine... but by powerband the turbo is at full boost and the s/C is only half way there.
I simplified this, but I think I made my point.
10-12-2007, 11:07 AM
#10
I had the same problem running my built N/A motor, I was breaking loose. If you where out at K-dale on any night other than fri/sat nights they dont prep the track all week long. my car was running 7.09 all motor and I went out there on a wed. night and ran a 7.98 at 102 mph with a 2.16 60' time.I wasnt catching till half track. I hate 1/8 mile. My car is so much faster in the 1/4.
