Time for a 58mm Throttle body??
07-10-2013, 05:03 PM
#21
Staging Lane
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07-10-2013, 05:41 PM
#23
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I just posted the CFM's here: https://ls1tech.com/forums/17536283-post20.html
Stock TPI/LT1 48mm Throttle Body w/o airfoil -- 783.0 cfm
Stock TPI/LT1 48mm Throttle Body w/ airfoil -- 821.9 cfm
TPI/LT1 52mm Throttle Body w/o airfoil -- 848.9 cfm
TPI/LT1 52mm Throttle Body w/ airfoil -- 898.8 cfm
Stock TPI/LT1 48mm Throttle Body w/o airfoil -- 783.0 cfm
Stock TPI/LT1 48mm Throttle Body w/ airfoil -- 821.9 cfm
TPI/LT1 52mm Throttle Body w/o airfoil -- 848.9 cfm
TPI/LT1 52mm Throttle Body w/ airfoil -- 898.8 cfm
07-10-2013, 05:52 PM
#24
If it is peaking at 5600 the problem is not the cam size, maybe cam timing or something else is choking it, maybe a tune issue, something but it is not the 503 cam causing that.
How was the rpm read? Was it a tach signal or a clamp or calculated from wheelspeed? I am going to guess calculated and just wrong.
People think "ported heads with bigger valves" is meaningful commentary and that flowbench numbers are the measure and can be dead wrong on both accounts.
The torque number the converter, not a real flywheel number.
Your HP number looks reasonable to me other than the peak rpm, everyone has inflated expectations, and you have generic heads. 95KPA is not a problem and says the intake tract and TB aren't really an issue. As discussed in several threads currently the LT1 MAP will read more vacuum than there really is.
You want the thing to make power stop trying to buy generic work, that you then want to compare to budget work, buy something good. The cam being about the last part of the combo I would change.
Too often folks buy "good as such and such" parts or just plain have inflated expectations and when they fail to meet expectations come up with excuses and swear by their mistakes thereby convincing others to repeat those mistakes.
Back to the torque numb er, you say the drag radials aren't spinning but then claim over 400tq right at the converter stall speed. Think about that.
How was the rpm read? Was it a tach signal or a clamp or calculated from wheelspeed? I am going to guess calculated and just wrong.
People think "ported heads with bigger valves" is meaningful commentary and that flowbench numbers are the measure and can be dead wrong on both accounts.
The torque number the converter, not a real flywheel number.
Your HP number looks reasonable to me other than the peak rpm, everyone has inflated expectations, and you have generic heads. 95KPA is not a problem and says the intake tract and TB aren't really an issue. As discussed in several threads currently the LT1 MAP will read more vacuum than there really is.
You want the thing to make power stop trying to buy generic work, that you then want to compare to budget work, buy something good. The cam being about the last part of the combo I would change.
Too often folks buy "good as such and such" parts or just plain have inflated expectations and when they fail to meet expectations come up with excuses and swear by their mistakes thereby convincing others to repeat those mistakes.
Back to the torque numb er, you say the drag radials aren't spinning but then claim over 400tq right at the converter stall speed. Think about that.
07-10-2013, 08:57 PM
#25
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I think I remember the dyno operator saying something about just guessing the wheel speed I don't remember. I doubt it's accurate because I shift at like 6300.
My torque numbers were like that the whole time
Yes I had radials and th best 60ft I could get was 1.80 they were consistent most of the runs and I only spun them 2/6 runs getting a 1.9 60ft
My torque numbers were like that the whole time
Yes I had radials and th best 60ft I could get was 1.80 they were consistent most of the runs and I only spun them 2/6 runs getting a 1.9 60ft
07-10-2013, 09:02 PM
#26
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I was planning to have a machine shop port the inlets for me
07-11-2013, 11:14 PM
#34
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I have stock 3.23s and would go 3.73. I was afraid at first but after seeing my friend run 373s in his ls1 A4 10bolt rearwith radials at the track for a while I feel more at ease
07-12-2013, 03:58 PM
#36
That would be my choice...it's what I run on my 383. I'd get a factory ported one since they are cheaper and have less issues than aftermarket TB's....you can pick one up rebuilt and ported to 52mm on ebay for around $150-200, and put an airfoil in it and get nearly 900CFM says dude^
