help me with Ideas to 60 better (adding nitrous to my pt88 ls2)
03-17-2013, 12:19 PM
#1
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help me with Ideas to 60 better (adding nitrous to my pt88 ls2) I think this may be more for the nitrous section but i want real world turbo/spray experince .
first of all heres my setup.
3200 pound firebird,
stock ls2 shortblock,ported 317's,ls6 intake , pt88 , e85, 127's injestors, full suspenison 325 radials,th400 braked, 3.42gears, 9inch, 3500-4000 stall. 850rwhp 18pounds
et 5.9x at 118-122mph with a 1.58 60'
anyways my car has never left well with the setup it has, ive been threw 4 convertors now and still no luck getting out of 1.5x's. I can build 4-6 pounds on the line, played with my tune a ton by leaning it up a tad and raising the timing to build boost. still only 6ish pounds.
Now once im off brake it hooks fine, leaves fine, just honestly feels "Soft" till i get to about the 60-100 foot mark. Then it leaves hard. The boost comes on so hard it picks the front up sometimes.
Now my idea is a 100-150 shot setup to come on right off the trans brake.
my question is should i run the nitrous all the way down the track or set it up on a hobbs switch?
i was almost thinking of just keeping the shot to a 100 and spray it the whole time to keep my fueling a little simplier and lower the IAT's (only at 175degs max now) and maybe that would make it safer on the motor? The fueling will be in the tune, not a wet shot.
Unless i can do a wet shot with a boost referenced FPR, but i dont think thats a good idea with ramping fuel pressure.
I dont have a boost controller, and im poor so i dont have that option right now.
first of all heres my setup.
3200 pound firebird,
stock ls2 shortblock,ported 317's,ls6 intake , pt88 , e85, 127's injestors, full suspenison 325 radials,th400 braked, 3.42gears, 9inch, 3500-4000 stall. 850rwhp 18pounds
et 5.9x at 118-122mph with a 1.58 60'
anyways my car has never left well with the setup it has, ive been threw 4 convertors now and still no luck getting out of 1.5x's. I can build 4-6 pounds on the line, played with my tune a ton by leaning it up a tad and raising the timing to build boost. still only 6ish pounds.
Now once im off brake it hooks fine, leaves fine, just honestly feels "Soft" till i get to about the 60-100 foot mark. Then it leaves hard. The boost comes on so hard it picks the front up sometimes.
Now my idea is a 100-150 shot setup to come on right off the trans brake.
my question is should i run the nitrous all the way down the track or set it up on a hobbs switch?
i was almost thinking of just keeping the shot to a 100 and spray it the whole time to keep my fueling a little simplier and lower the IAT's (only at 175degs max now) and maybe that would make it safer on the motor? The fueling will be in the tune, not a wet shot.
Unless i can do a wet shot with a boost referenced FPR, but i dont think thats a good idea with ramping fuel pressure.
I dont have a boost controller, and im poor so i dont have that option right now.
03-17-2013, 12:43 PM
#2
I think you only need a very small shot of n20 to do what you are wanting, remember a little n20 will make more HP on boost then just motor. With 50hp n20 it will make over 100hp difference. Start with a small shot and see how much it improves then you can go up gradually if needed.
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03-17-2013, 04:00 PM
#9
A 232 lobe installed on a 114 intake centerline has an intake valve close point of 50 abdc at .050....
For a 3.622 stroke motor that is LATE.
Advance the cam 4 degrees... leave full N/a timing in till 5-6 psi boost and report back. A 46 ivc is more inline with where it needs to be.
And if thats an FTI converter.... you might be ok. Thier turbo stuff is hit and miss.
Rick prospero had one of theres in his wagon... ran 183 mph... borrowed a different converter from someone while he was on drag week to test... and went 186.
For a 3.622 stroke motor that is LATE.
Advance the cam 4 degrees... leave full N/a timing in till 5-6 psi boost and report back. A 46 ivc is more inline with where it needs to be.
And if thats an FTI converter.... you might be ok. Thier turbo stuff is hit and miss.
Rick prospero had one of theres in his wagon... ran 183 mph... borrowed a different converter from someone while he was on drag week to test... and went 186.
03-17-2013, 10:07 PM
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A 232 lobe installed on a 114 intake centerline has an intake valve close point of 50 abdc at .050....
For a 3.622 stroke motor that is LATE.
Advance the cam 4 degrees... leave full N/a timing in till 5-6 psi boost and report back. A 46 ivc is more inline with where it needs to be.
For a 3.622 stroke motor that is LATE.
Advance the cam 4 degrees... leave full N/a timing in till 5-6 psi boost and report back. A 46 ivc is more inline with where it needs to be.
can you explain the cause and effect of this? end result should be faster spool right?
03-17-2013, 10:17 PM
#11
It also advances the exhaust valve open event... which means the cylinder will be at a higher pressure when its opened.
This will also,usually, bring the operating rpm range of the motor down some. So if your motor makes crazy power upstairs but lacks bottom end grunt... advancing the cam will help. Same is true of the opposite... if you have a ton of bottom end power and its not pulling upstairs like you think it should... you can retard its icl to move its operating range higher in the rpm band.
Playing with where the cam is can be a big tuning tool.... if your willing to play with it... and find out what your motor likes.
03-17-2013, 10:20 PM
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Close the intake valve sooner and it raises the dynamic compression.... more cylinder pressure... more heat... more energy for the turbine.
It also advances the exhaust valve open event... which means the cylinder will be at a higher pressure when its opened.
This will also,usually, bring the operating rpm range of the motor down some. So if your motor makes crazy power upstairs but lacks bottom end grunt... advancing the cam will help. Same is true of the opposite... if you have a ton of bottom end power and its not pulling upstairs like you think it should... you can retard its icl to move its operating range higher in the rpm band.
Playing with where the cam is can be a big tuning tool.... if your willing to play with it... and find out what your motor likes.
It also advances the exhaust valve open event... which means the cylinder will be at a higher pressure when its opened.
This will also,usually, bring the operating rpm range of the motor down some. So if your motor makes crazy power upstairs but lacks bottom end grunt... advancing the cam will help. Same is true of the opposite... if you have a ton of bottom end power and its not pulling upstairs like you think it should... you can retard its icl to move its operating range higher in the rpm band.
Playing with where the cam is can be a big tuning tool.... if your willing to play with it... and find out what your motor likes.
03-17-2013, 11:09 PM
#15
Post 7 and 8. I asked if it was installed straight up... he said yes. I asked if there was any advance ground into it... he said no. That will result in an intake centerline that is equal to the lobe seperation.
03-17-2013, 11:43 PM
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what size pipe did you use on your cross over? headers? i would save your "nitrous money" and get a boost controller...
Last edited by 6.0mustang; 03-17-2013 at 11:53 PM.
03-18-2013, 11:41 AM
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No need for nitrous, My 3700 lb raceweight with pt88, 3.08 gears on 275/60s has been 1.33 and 1.35 with 2 different converters leaving on 5 psi. How quickly is the boost going from 5 to peak boost? Mine does it in .4 of a second, try playing with the timing tables. I have I believe 22 degrees timing untill 5 psi, then it goes down as boost goes up and settles around 14 - 15 degrees at 17 psi.
I expect to see 1.2x 60 foots with travel limiters and a spool. There has to be something wrong somewhere if your struggling so hard to even get a 1.4 60. I got 1.47 60 foots with my 6 speed.
I expect to see 1.2x 60 foots with travel limiters and a spool. There has to be something wrong somewhere if your struggling so hard to even get a 1.4 60. I got 1.47 60 foots with my 6 speed.
A 232 lobe installed on a 114 intake centerline has an intake valve close point of 50 abdc at .050....
For a 3.622 stroke motor that is LATE.
Advance the cam 4 degrees... leave full N/a timing in till 5-6 psi boost and report back. A 46 ivc is more inline with where it needs to be.
And if thats an FTI converter.... you might be ok. Thier turbo stuff is hit and miss.
Rick prospero had one of theres in his wagon... ran 183 mph... borrowed a different converter from someone while he was on drag week to test... and went 186.
For a 3.622 stroke motor that is LATE.
Advance the cam 4 degrees... leave full N/a timing in till 5-6 psi boost and report back. A 46 ivc is more inline with where it needs to be.
And if thats an FTI converter.... you might be ok. Thier turbo stuff is hit and miss.
Rick prospero had one of theres in his wagon... ran 183 mph... borrowed a different converter from someone while he was on drag week to test... and went 186.
It is a fti, but im not blaming then for anything, im horrable at explaining what my car does to them. Also im a cheap ***.
Close the intake valve sooner and it raises the dynamic compression.... more cylinder pressure... more heat... more energy for the turbine.
It also advances the exhaust valve open event... which means the cylinder will be at a higher pressure when its opened.
This will also,usually, bring the operating rpm range of the motor down some. So if your motor makes crazy power upstairs but lacks bottom end grunt... advancing the cam will help. Same is true of the opposite... if you have a ton of bottom end power and its not pulling upstairs like you think it should... you can retard its icl to move its operating range higher in the rpm band.
Playing with where the cam is can be a big tuning tool.... if your willing to play with it... and find out what your motor likes.
It also advances the exhaust valve open event... which means the cylinder will be at a higher pressure when its opened.
This will also,usually, bring the operating rpm range of the motor down some. So if your motor makes crazy power upstairs but lacks bottom end grunt... advancing the cam will help. Same is true of the opposite... if you have a ton of bottom end power and its not pulling upstairs like you think it should... you can retard its icl to move its operating range higher in the rpm band.
Playing with where the cam is can be a big tuning tool.... if your willing to play with it... and find out what your motor likes.
Heres a 3rd gear 3000rpm to 6500rpm pull on a dynojet. 15-16 pounds.
Im hoping it is, im about to order a adjustable cam gear.
backwards truck manifolds, 2.5inch pipe to a t4 merge and a 4 inch down pipe dumped down.
03-18-2013, 12:18 PM
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Sounds like a lot of things you can do before you resort to nitrous. Get your cam right (as stated by lil jon), you could go to a 2.25 crossover, timing adjustments, maybe fuel adjust ments. Sounds like a promising setup. But you know its all about that 330ft if your lookin for good e.t.
