Is the torquer 2 big enough for a 408?
So, I'm not asking for exact specs, but giving that I'll be using the 5.3 heads, what size cam can I get away with in a 408 that would give me the driveability of a t2 in a stock cubed motor? Judging from what I'm gathering from what you guys have been talking about...would I need something in the 230-240 range on the intake side, and 240+ on the exhaust side, on a 115 lsa? What kind of lift would I be looking at assuming my piston has 8cc valve reliefs?
http://www.tickperformance.com/tick-...1-ls6-engines/
If you look at the 600rwhp Cathedral port 427+cid motors, all of them have massive overlap but extremely wide LSAs. 250/260 115 type cams. Why? Broaden the torque curve across the massive engine's RPM range.
Even on heads like AFR, Mamo and Curtis and others all agree that you don't need to use overlap as a crutch for the intake charge. If heads have 85% I/E efficiency, you can go with enough duration and set the ICL where you want to get optimal VEs that don't rely on the cam to create cylinder pressure. You rely on compression and head efficiency (both I/E ratio and especially velocity relative to a given CSA) to make power with a given set of VEs.
The other big thing people don't think about and it plays right back into the hands of overlap and what I just said above is 9/10 times these large cubic inch LSx street engines have Fast intake manifolds on them. They have a 10" long intake runner and create an intertia-ram column of air all on their own. They don't need as much overlap as others have said to create a strong mid-range signal and if you over-scavenge them with a lot of overlap at or around TDC you will kill off that power band. This is even more so an issue as the intake valve gets larger and larger and creates more curtain area.
So, I'm not asking for exact specs, but giving that I'll be using the 5.3 heads, what size cam can I get away with in a 408 that would give me the driveability of a t2 in a stock cubed motor? Judging from what I'm gathering from what you guys have been talking about...would I need something in the 230-240 range on the intake side, and 240+ on the exhaust side, on a 115 lsa? What kind of lift would I be looking at assuming my piston has 8cc valve reliefs?
9/10 times these large cubic inch LSx street engines have Fast intake manifolds on them. They have a 10" long intake runner and create an intertia-ram column of air all on their own. They don't need as much overlap as others have said to create a strong mid-range signal and if you over-scavenge them with a lot of overlap at or around TDC you will kill off that power band.
Now I am not a physics expert, and I will admit I have never even taken a physics class in my life(I am actually enrolling in a few classes this spring at the local community college to further my understanding of valvetrain movements and events...wish me luck), but I have a pretty good grasp of how it works.
Thanks for a great civil discussion Tigger, the site needs more of this instead of the poo slinging that usually occurs. I have noticed though that if a few certain members stay out of a thread, that normally doesn't happen...funny how that works.
Thread Starter
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Joined: Feb 2002
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From: Silver Spring, Md.
Ok, it looks like I'm about to get this project started. Though I still haven't decided on my cam yet, I'll be making a call to Martin tomorrow. I do have a couple other questions though. My current setup has an unported FAST 90. Will this be sufficient or will I need to look into having it ported? Would an unported FAST 102 be just as effective? What about exhaust...do I need to now consider 1 7/8 headers now to reach my goals?
Thread Starter
11 Second Club
Joined: Feb 2002
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From: Silver Spring, Md.
Ok, it looks like I'm about to get this project started. Though I still haven't decided on my cam yet, I'll be making a call to Martin tomorrow. I do have a couple other questions though. My current setup has an unported FAST 90. Will this be sufficient or will I need to look into having it ported? Would an unported FAST 102 be just as effective? What about exhaust...do I need to now consider 1 7/8 headers now to reach my goals?
Ok, it looks like I'm about to get this project started. Though I still haven't decided on my cam yet, I'll be making a call to Martin tomorrow. I do have a couple other questions though. My current setup has an unported FAST 90. Will this be sufficient or will I need to look into having it ported? Would an unported FAST 102 be just as effective? What about exhaust...do I need to now consider 1 7/8 headers now to reach my goals?
I replaced my stock LS6 short block with a TSP 418. Reused my TFS 215 heads (opened the chamber to match the bore), LG G5X3 114 cam (234/242/.600/.610) installed at 114 ICL, Mamofied 90/90 intake, LG long tube pro 1.75 headers with high flow cats & 3" Big 3 exhaust. The CR is 11.48.
With the 5.7 engine there was a light throttle/low RPM surge (4th gear @ 30 mph) that I hoped would be better with the 418 engine. But the surge was only slightly improved. Also I'm tired of the valve clatter at certain rpm's.
So I'm looking at a smaller cam like a comp LSL 231/.615 int & LXL 234/.612 ex. on a 114 LSA. This cam will have 4.5* overlap vs 10* overlap of the G5X3. I don't see how a 243/250 114 cam with 18.25* overlap would have the same driveabililty in a 408 as a the Torquer V2 cam in a 346.
Also waiting on EPS to spec me a cam with his LSG lobes.
Russ Kemp
With the 5.7 engine there was a light throttle/low RPM surge (4th gear @ 30 mph) that I hoped would be better with the 418 engine. But the surge was only slightly improved. Also I'm tired of the valve clatter at certain rpm's.
So I'm looking at a smaller cam like a comp LSL 231/.615 int & LXL 234/.612 ex. on a 114 LSA. This cam will have 4.5* overlap vs 10* overlap of the G5X3. I don't see how a 243/250 114 cam with 18.25* overlap would have the same driveabililty in a 408 as a the Torquer V2 cam in a 346.
Also waiting on EPS to spec me a cam with his LSG lobes.
Russ Kemp
Last edited by Russ K; Jan 11, 2013 at 04:02 PM.
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Verdad Gallardo I replaced my stock LS6 short block with a TSP 418. Reused my TFS 215 heads (opened the chamber to match the bore), LG G5X3 114 cam (234/242/.600/.610) installed at 114 ICL, Mamofied 90/90 intake, LG long tube pro 1.75 headers with high flow cats & 3" Big 3 exhaust. The CR is 11.48.
With the 5.7 engine there was a light throttle/low RPM surge (4th gear @ 30 mph) that I hoped would be better with the 418 engine. But the surge was only slightly improved. Also I'm tired of the valve clatter at certain rpm's.
So I'm looking at a smaller cam like a comp LSL 231/.615 int & LXL 234/.612 ex. on a 114 LSA. This cam will have 4.5* overlap vs 10* overlap of the G5X3. I don't see how a 243/250 114 cam with 18.25* overlap would have the same driveabililty in a 408 as a the Torquer V2 cam in a 346.
Also waiting on EPS to spec me a cam with his LSG lobes.
Russ Kemp
With the 5.7 engine there was a light throttle/low RPM surge (4th gear @ 30 mph) that I hoped would be better with the 418 engine. But the surge was only slightly improved. Also I'm tired of the valve clatter at certain rpm's.
So I'm looking at a smaller cam like a comp LSL 231/.615 int & LXL 234/.612 ex. on a 114 LSA. This cam will have 4.5* overlap vs 10* overlap of the G5X3. I don't see how a 243/250 114 cam with 18.25* overlap would have the same driveabililty in a 408 as a the Torquer V2 cam in a 346.
Also waiting on EPS to spec me a cam with his LSG lobes.
Russ Kemp
Also if you're just looking at overlap figures@.050" and using that figure to determie whether or not you think the drivability will be impoved upon or decreased, you're only looking at a very small portion of entire picture. Seat to seat overlap figures(.006" a.k.a. advertised duration) plays just as large of a part in drivability if not more than the @.050" numbers. This is where lobe selection plays a critical part in cam selection as you can have the same @.050" numbers as another cam profile, but be totally different @.200" and @.006".
Russ those XE-R lobes your current cam has are notorious for clattering and banging around especially at idle making for the "sewing machine" noise that is frequently discussed and talked about on this site. Ramp rates, assymetrical vs. symmetrical lobes, and lifter preload are big big variables in this equation for having a quiet valve-train
Russ those XE-R lobes your current cam has are notorious for clattering and banging around especially at idle making for the "sewing machine" noise that is frequently discussed and talked about on this site. Ramp rates, assymetrical vs. symmetrical lobes, and lifter preload are big big variables in this equation for having a quiet valve-train
Thread Starter
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Joined: Feb 2002
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From: Silver Spring, Md.
Realisticly, in a 408, what could you expect to see by going from the ported 5.3 heads to a set of high-end castings like the PRC 237, AFR, or Trick Flow? I understand that a cam optimized to work with the 5.3s wouldn't be the best for the better heads but what would a set of heads alone gain?
pretty awesome thread here! i like that big dave is into pinching pennies like me!!!!
RUSS K----got any dyno results before after the shortblock swap??? interested in seeing...
and on the heads...they would gain for sure.
i once was told, "if you have the worlds best heads and a mediocre cam...youll make great power...but crappy heads with the best cam you can get....you wont make good power..."
---may be opening a can of worms on this one...awesome cam info here...now onto the heads...lol
RUSS K----got any dyno results before after the shortblock swap??? interested in seeing...
and on the heads...they would gain for sure.
i once was told, "if you have the worlds best heads and a mediocre cam...youll make great power...but crappy heads with the best cam you can get....you wont make good power..."
---may be opening a can of worms on this one...awesome cam info here...now onto the heads...lol
Thread Starter
11 Second Club
Joined: Feb 2002
Posts: 955
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From: Silver Spring, Md.
I was totally against the 408, mainly because of the weight. When I added up what an aluminum 402 would've costed, the 408 made more sense. I don't plan on autocrossing my car, and the additional weight on the nose won't help in drag racing, but I'm hoping to overcome those factors with some good ole fashion horsepower...and torque.
Last edited by big dave; Feb 5, 2013 at 05:43 PM.
Geoff specced a 234/242 .602/.615 117 +2 camshaft. Should have more top end power with a smoother idle & very little to no low RPM/light throttle surge with 4* overlap. Plus no more valve clatter.
Russ Kemp
