cam guru's in here please...(Pat and predator Z)
12-27-2006, 05:48 PM
#41
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Originally Posted by SVThis
hey guys...im bout to start a cam swap on my car but as u all know its a hard to decide with all the cams out there (expectially when u dont know much about cams)
welp, to help you pick the cam for me here is what id like to have...
I want a LOUD, HARD LOPEY cam that will sound really agressive on crusie ins and such. My car is NOT a DD in fact it only gets drove on warm, sunny, summer weekends, so high lifts and long durations dont scare me...also its an automatic and i dont wanna STALL the crap out of my car (thats what makes my decition so hard or id just throw in the T-REX)...also i want it to be a street beast cause i dont go to the track much, yet i do some. this is will be a cam only application for a good while as well considering im a college student will small money funds...
thanx in advance and if u have any more questions, ask and ill answer
welp, to help you pick the cam for me here is what id like to have...
I want a LOUD, HARD LOPEY cam that will sound really agressive on crusie ins and such. My car is NOT a DD in fact it only gets drove on warm, sunny, summer weekends, so high lifts and long durations dont scare me...also its an automatic and i dont wanna STALL the crap out of my car (thats what makes my decition so hard or id just throw in the T-REX)...also i want it to be a street beast cause i dont go to the track much, yet i do some. this is will be a cam only application for a good while as well considering im a college student will small money funds...
thanx in advance and if u have any more questions, ask and ill answer
12-27-2006, 06:27 PM
#42
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Originally Posted by JimMueller
So you don't agree with shifting later if it gives you better acceleration due to gearing? Are you saying that it's ideal to choose a package where you must shift soon after peak hp?
12-27-2006, 07:13 PM
#44
Originally Posted by N4cer
The shift point depends on how the power carries out, and gearing. So whoever told you that rule of thumb lied to you.
Shift points vary from car to car based on way too many variables, especially if the car's an automatic. Best thing to do is to test varying shift points at the track and see which rpm nets you the best ET and mph. 10% over might be OK for a wide ratio 4 speed, but poor for close ratio 6 speed.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
12-27-2006, 07:45 PM
#45
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I hit the stock 6200 rev limiter every WOT shift now {even 5th 
} with 4.11's , before with stock 3.42's the engine seemed to give out around 5700rpm . Night and day difference with the gear swap . My car is stock internal.
} with 4.11's , before with stock 3.42's the engine seemed to give out around 5700rpm . Night and day difference with the gear swap . My car is stock internal.
12-28-2006, 01:06 AM
#46
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It's a general rule of thumb, get it? It actually works pretty well, as long as the HP doesn't peak at say for exapmple 6600 and then takes a nose dive by 6800. Rear end gearing also play a big factor on shift points, not just tranny gear ratios. You can gear a car for best ET, best MPH or a combination of both. Take for instance Stock Eliminator cars, they trap way better than their MPH would indicate. Why? Because they're geared for ET not MPH. With them it's all about the first 330'.
12-28-2006, 01:11 AM
#47
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The proper way to choose tranny and rear gear ratios so as to maximize 1/4 mile performance is with an engine dyno. The numbers spat out by a chassis dyno have too many variables included in there.
12-28-2006, 01:29 AM
#48
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I maybe opening a can of worms here but if a cam carries a flatline beyond 500 rpm of peak, there is someting holding up that cam in the intake department.
Meaning with proper air it would peak higher, therefore shifting the actual peak later and actual shifting point would still be the same but closer to peak.
I hope I made sense.
On A4s we also rely on stall shift extentions (in addition to trans gears and diff gears)
Meaning with proper air it would peak higher, therefore shifting the actual peak later and actual shifting point would still be the same but closer to peak.
I hope I made sense.
On A4s we also rely on stall shift extentions (in addition to trans gears and diff gears)
12-28-2006, 01:22 PM
#49
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Originally Posted by OhIt'sBeenBraughten
It's a general rule of thumb, get it? It actually works pretty well, as long as the HP doesn't peak at say for exapmple 6600 and then takes a nose dive by 6800. Rear end gearing also play a big factor on shift points, not just tranny gear ratios. You can gear a car for best ET, best MPH or a combination of both. Take for instance Stock Eliminator cars, they trap way better than their MPH would indicate. Why? Because they're geared for ET not MPH. With them it's all about the first 330'.
I agree it actually works quite well and gives a excellent starting point.As stated trail and error at the strip is the best way. In the " old days" we did not have rwhp dynos and the HP curves dorped of pretty fast. The 10% rule worked pretty well.I have a A4 with a 3600 stall. My shift extension with this stall is 4700/4800 rpm. Meaning when I shift my RPM drops to 4700/4800 RPM.This means I should not shift until my HP drops off to what it is at 4700/4800 RPM. The problem is that on some cams I can't do this because I have stock internals and can't/wont rev that high. I found that with the stock cam 6300 rpm gave me my best times.
12-28-2006, 05:56 PM
#50
Shift points are not an easy analysis with a converter. Sure you're at 4700 on an upshift (using Yankee's example), but you also may have some torque multiplation on the upshift depending upon the speed of the converter output shaft. On the top end, you're losing HP to the converter. Average torque to the wheels is a product of all the factors: engine, converter, tranny gear, and rear gear (rear being a constant).
The wide ratios of an A4 generally benefit from spinning higher.
The wide ratios of an A4 generally benefit from spinning higher.
12-28-2006, 06:28 PM
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Originally Posted by Ragtop 99
Shift points are not an easy analysis with a converter. Sure you're at 4700 on an upshift (using Yankee's example), but you also may have some torque multiplation on the upshift depending upon the speed of the converter output shaft. On the top end, you're losing HP to the converter. Average torque to the wheels is a product of all the factors: engine, converter, tranny gear, and rear gear (rear being a constant).
The wide ratios of an A4 generally benefit from spinning higher.
The wide ratios of an A4 generally benefit from spinning higher.
12-28-2006, 09:52 PM
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Originally Posted by hammertime
Not sure I understand this statement, can you explain?
12-28-2006, 10:01 PM
#54
Originally Posted by PREDATOR-Z
I maybe opening a can of worms here but if a cam carries a flatline beyond 500 rpm of peak, there is someting holding up that cam in the intake department.
Meaning with proper air it would peak higher, therefore shifting the actual peak later and actual shifting point would still be the same but closer to peak.
I hope I made sense.
On A4s we also rely on stall shift extentions (in addition to trans gears and diff gears)
Meaning with proper air it would peak higher, therefore shifting the actual peak later and actual shifting point would still be the same but closer to peak.
I hope I made sense.
On A4s we also rely on stall shift extentions (in addition to trans gears and diff gears)
12-29-2006, 02:25 AM
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Everyone harps about the LS1 being intake restricted. Guess folks forgot what a 5.0 EFI intake looks like. A stock LS1 (with LS6 intake) with headers produces peak torque at 4400 RPM. Guess Yank was on to something when they came up with the PT4400 huh? The LS1 becomes intake restricted when guys throw huge cams at the motor that cause the peak HP to be elevated to 6400+ RPM. There's that big cam syndrome rearing it's face again.
The LS1 is the baddest small block to ever run in Stock Eliminator. Why? The heads and intake.
Plenty of guys have gone mid 10s on motor with an LS6 intake. How many have you seen run that with a stock 5.0 EFI intake even with heads that flow as good as LS1 heads do? Try it with a TPI also.
The LS1 is the baddest small block to ever run in Stock Eliminator. Why? The heads and intake.
Plenty of guys have gone mid 10s on motor with an LS6 intake. How many have you seen run that with a stock 5.0 EFI intake even with heads that flow as good as LS1 heads do? Try it with a TPI also.
