What max size cam to use with CATS on 408ci?
12-10-2005, 07:43 AM
#1
What max size cam to use with CATS on 408ci? Let's say I want to build a "streetable" 408ci M6 car. My HP & TQ goals are 510 RWHP and 485 RWTQ.
I would use:
- FAST 90 Port Matched Intake and 90 TB
- AFR or ET Heads (Ported?)
- 1 3/4 LT
- 11.5 CR
- 85mm MAF
- 85mm Lid
- E-Cutout
- GMMG Cat Back
- Electric Water Pump
- ASP Underdrive Pulley
- SVO 42 lb Injectors
- 12 Bolt 3.42 Gear
- Cartek Clutch with Stock Flywheel
I'm not sure on cam specs, but I do have a few in mind:
- 236 240 118lsa (+2 degrees of over lap)
- 238 242 118lsa (+4 degrees of over lap)
I know with a cam that big I won't pass emissions and don't have to or plan to. The reasons I want CATS are:
- Cut down on exhaust smell
- Reduce exhaust rasp when I get on it (WOT)
- Quiet the car down some when cruising
How big of a cam can I use with CATS? Will having no valve overlap hurt the CATS over time even if I have a really good tune (tuned with Wideband) and COT enabled?
You don't see many, if any threads like this. What are your thoughts guys?
I would use:
- FAST 90 Port Matched Intake and 90 TB
- AFR or ET Heads (Ported?)
- 1 3/4 LT
- 11.5 CR
- 85mm MAF
- 85mm Lid
- E-Cutout
- GMMG Cat Back
- Electric Water Pump
- ASP Underdrive Pulley
- SVO 42 lb Injectors
- 12 Bolt 3.42 Gear
- Cartek Clutch with Stock Flywheel
I'm not sure on cam specs, but I do have a few in mind:
- 236 240 118lsa (+2 degrees of over lap)
- 238 242 118lsa (+4 degrees of over lap)
I know with a cam that big I won't pass emissions and don't have to or plan to. The reasons I want CATS are:
- Cut down on exhaust smell
- Reduce exhaust rasp when I get on it (WOT)
- Quiet the car down some when cruising
How big of a cam can I use with CATS? Will having no valve overlap hurt the CATS over time even if I have a really good tune (tuned with Wideband) and COT enabled?
You don't see many, if any threads like this. What are your thoughts guys?
12-10-2005, 09:22 AM
#3
TECH Senior Member
Get metallic cats. 400cfm min.
your choices are very street friendly, overlap is light. cats tend to burnout under extended max rpms and if to much carbon/fuel residue in exhaust.
It will all depend greatly on your tune for idle and normal cruising.
your choices are very street friendly, overlap is light. cats tend to burnout under extended max rpms and if to much carbon/fuel residue in exhaust.
It will all depend greatly on your tune for idle and normal cruising.
12-10-2005, 09:41 AM
#6
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how much overlap would be too much for cats? I have a F13/112+4 and wanting to run high flow cats.
didn't mean to hijack your thread man, just as curious as you are......
didn't mean to hijack your thread man, just as curious as you are......
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12-11-2005, 08:52 AM
#8
Too much overlap is a no no when running cats, but the cams you've chosen are a little too conservative on the overlap end, even with cats. I'd suggest closing the LSA to at least 114. The 118LSA is going to open the exhaust valve so early that you're going to bleed off too much cylinder pressure too soon.
FWIW, I'm running about 10 degrees of overlap with my 346 and high flow cats. You can get away with a little more on a bigger motor.
FWIW, I'm running about 10 degrees of overlap with my 346 and high flow cats. You can get away with a little more on a bigger motor.
__________________
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.
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.
12-11-2005, 11:21 AM
#9
Originally Posted by Patrick G
Too much overlap is a no no when running cats, but the cams you've chosen are a little too conservative on the overlap end, even with cats.
A stock 2001-2002 F-Body ls1 cam specs out to:
196.37 intake 208.72 exhaust LSA 115.92
So if we do the math:
196.37 + 208.72 = 405.09
405.09 / 4 = 101.27
101.27 - 115.92 = -14.65
-14.65 * 2 = [/b]-29.3 degrees of valve overlap[/b]
I've heard from many California guys claiming that a TR 224 114lsa cam will pass emissions with cats in place and that cam has -4 degrees of overlap
Originally Posted by Patrick G
I'd suggest closing the LSA to at least 114. The 118LSA is going to open the exhaust valve so early that you're going to bleed off too much cylinder pressure too soon.
Could you suggest a cam that would meet my "goals", if so, what would it be? Remember, I'm not looking to pass emissions at all and don't expect to.
Bill
12-11-2005, 04:36 PM
#10
Why run cats at all??? All your goal is to just quiet it down alittle and not worry about emissions right? Why not put a bullet muffler or something like that in there where the cats would be? Why spend $100+ on a set of cats when you can get a set of bullets for about the same price plus you don't have to worry about the cats plugging up or the insides getting broken up. Plus the backpressure from a cat is probiably the same for a bullet muffler if not more even. Plus if you were to get pulled for whatever reason and they look under your car upon a generic inspection somebody could easily assume those cats.
12-11-2005, 08:21 PM
#11
Originally Posted by Billiumss
Are you talking negative or positive overlap?
A stock 2001-2002 F-Body ls1 cam specs out to:
196.37 intake 208.72 exhaust LSA 115.92
So if we do the math:
196.37 + 208.72 = 405.09
405.09 / 4 = 101.27
101.27 - 115.92 = -14.65
-14.65 * 2 = [/b]-29.3 degrees of valve overlap[/b]
I've heard from many California guys claiming that a TR 224 114lsa cam will pass emissions with cats in place and that cam has -4 degrees of overlap
Please explain more on this. I want to know why. I figured it would be the other way around. Doesn't a 01-04 Z06 have a cam that spec'd out at 119.5 lsa?
Could you suggest a cam that would meet my "goals", if so, what would it be? Remember, I'm not looking to pass emissions at all and don't expect to.
Bill
A stock 2001-2002 F-Body ls1 cam specs out to:
196.37 intake 208.72 exhaust LSA 115.92
So if we do the math:
196.37 + 208.72 = 405.09
405.09 / 4 = 101.27
101.27 - 115.92 = -14.65
-14.65 * 2 = [/b]-29.3 degrees of valve overlap[/b]
I've heard from many California guys claiming that a TR 224 114lsa cam will pass emissions with cats in place and that cam has -4 degrees of overlap
Please explain more on this. I want to know why. I figured it would be the other way around. Doesn't a 01-04 Z06 have a cam that spec'd out at 119.5 lsa?
Could you suggest a cam that would meet my "goals", if so, what would it be? Remember, I'm not looking to pass emissions at all and don't expect to.
Bill
204/218 117LSA 119ICL
Intake valve closing point (IVC): 41 degrees ABDC
Exhaust valve opening point (EVO): 44 degrees BBDC
-23 degrees of overlap at .050"
Look at another popular cam:
TR 224/224 112LSA 112ICL
IVC 44 degrees ABDC
EVO 44 degrees BBDC
0 degrees overlap at .050"
Now the T-Rex:
242/248 110LSA 108ICL
IVC 49 degrees ABDC
EVO 56 degrees BBDC
25 degrees of overlap at .050"
Your cam:
238/242 118LSA 114ICL
IVC 53 degrees ABDC (too late. Too high of an engine peak, weak dynamic compression)
EVO 63 degrees BBDC (too early. You will bleed off cylinder pressure 7 degrees earlier than a T-Rex costing you precious torque)
Ugly cam that won't make good power IMO.
As you can see, even though the LS6 cam and your 118LSA cam have similar LSAs, the intake valve and exhaust valve events are completely different.
__________________
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.
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.
12-12-2005, 03:51 PM
#18
12-12-2005, 04:42 PM
#19
Originally Posted by PREDATOR-Z
This is what I just put in mine
232/234, .595/.598 113 LSA +0 Advance
3-IVO
49-IVC
50-EVO
4-EVC
113-ECL
7*-Overlap
(Firing it up tomorow)
232/234, .595/.598 113 LSA +0 Advance
3-IVO
49-IVC
50-EVO
4-EVC
113-ECL
7*-Overlap
(Firing it up tomorow)
