Victor Jr. vs FAST 92mm
08-09-2016, 07:46 AM
#1
Victor Jr. vs FAST 92mm Trying to decide, based on my combo, which intake is going to yield better results. A Victor Jr. w/ 4150 style TB or a FAST 92/92 setup. I recently added bigger 1 7/8" headers to the combo, and while I picked up quite a bit of under the curve power and torque, it actually peaked lower than it did with the smaller 1 3/4" headers and really nosed over at around 6,000 RPM's. Martin Smallwood and Brian Tooley feel it's due to over-scavenging. I attached the graph below. Both feel that a better intake/TB setup will fix the issue. Based on my current setup, and the cam specs, which intake/TB setup do you think will be better, particularly in the upper RPM band (6,000 RPM+).
Current Mods:
AI Dart/RHS CNC ported 223cc heads
Tick Performance 227/235 110 LSA cam (Valve timing INT: 6 BTDC. 40 ABDC. Valve timing EXH: 50 BBDC. 4 ATDC. 107 Intake Center Line)
Speed Engineering 1 7/8" long tube headers
Texas Speed 3" true duals
Stock LS6 intake/stock TB
Accel 44lb/hr injectors
Current Mods:
AI Dart/RHS CNC ported 223cc heads
Tick Performance 227/235 110 LSA cam (Valve timing INT: 6 BTDC. 40 ABDC. Valve timing EXH: 50 BBDC. 4 ATDC. 107 Intake Center Line)
Speed Engineering 1 7/8" long tube headers
Texas Speed 3" true duals
Stock LS6 intake/stock TB
Accel 44lb/hr injectors
Last edited by Rise of the Phoenix; 08-09-2016 at 07:55 AM.
08-09-2016, 08:08 AM
#4
The runners on the Vic Jr are shorter so they'll tend to perform better at higher RPM like what you're wanting. I think the 92mm has 10.5 or 11 inch long runners while the Vic Jr runners are 6.5 and 7.5 inch long. The Vic Jr tends to perform better with tighter LSA camshafts, so it may work really well with what you have now.
08-09-2016, 08:18 AM
#7
The runners on the Vic Jr are shorter so they'll tend to perform better at higher RPM like what you're wanting. I think the 92mm has 10.5 or 11 inch long runners while the Vic Jr runners are 6.5 and 7.5 inch long. The Vic Jr tends to perform better with tighter LSA camshafts, so it may work really well with what you have now.
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08-09-2016, 08:36 AM
#9
It's my friend's dyno (Mustang Dyno) and it was basically brand new when we put the car on it. It took a little time for him to figure out the calibrations and get it working right.
Another questions is this: If I do a Victor Jr. setup, how much of a difference will there be between a 4150 TB versus an elbow/TB setup?
Another questions is this: If I do a Victor Jr. setup, how much of a difference will there be between a 4150 TB versus an elbow/TB setup?
08-09-2016, 08:50 AM
#10
That's kind of what I was thinking too. I know guys like you are far smarter when it comes to cams and valve events, and I've always been told that if you're going to run a Victor Jr. or a Super Victor, you need to make sure the cam is spec'd for that particular intake. I was just curious with the valve events of my cam, if the Victor Jr. would be a better fit.
http://www.hotrod.com/articles/20-ls...ifolds-tested/
Meanwhile, there are several threads on here where people have picked up peak power over a FAST or LS6 intake, so results are kind of all over the place. I still think your cam is wrong for what you have, but it might be just right with a carb style intake.
08-09-2016, 09:15 AM
#12
Only reason I'm contemplating a Victor Jr. is because I think it might be the best choice give my cam, and I don't want to have to cut up the car and lose wipers.
08-09-2016, 09:37 AM
#13
I don't think I've ever seen a combo where any intake performed better than a Fast as a whole for what I would want in a street car.
A hi ram type intake will make a good bit more starting above 5,000-5,500rpm or so and pull like mad well after a Fast noses over, but at the sacrifice of as much as ~25-30 hp below 5,000rpm.
And IIRC the mid length and short length carb style intakes usually perform worse everywhere. I might be mistaken on that though.
A hi ram type intake will make a good bit more starting above 5,000-5,500rpm or so and pull like mad well after a Fast noses over, but at the sacrifice of as much as ~25-30 hp below 5,000rpm.
And IIRC the mid length and short length carb style intakes usually perform worse everywhere. I might be mistaken on that though.
08-09-2016, 09:57 AM
#15
I don't think I've ever seen a combo where any intake performed better than a Fast as a whole for what I would want in a street car.
A hi ram type intake will make a good bit more starting above 5,000-5,500rpm or so and pull like mad well after a Fast noses over, but at the sacrifice of as much as ~25-30 hp below 5,000rpm.
And IIRC the mid length and short length carb style intakes usually perform worse everywhere. I might be mistaken on that though.
A hi ram type intake will make a good bit more starting above 5,000-5,500rpm or so and pull like mad well after a Fast noses over, but at the sacrifice of as much as ~25-30 hp below 5,000rpm.
And IIRC the mid length and short length carb style intakes usually perform worse everywhere. I might be mistaken on that though.
You've got me seriously thinking about a LLSR cam. I know the cam I have right now is not ideal for the heads I have, so if I'm going to change it out at some point, maybe it wouldn't be a bad idea to go with a custom LLSR, especially if you can use stock rockers if you shim them.
08-09-2016, 10:11 AM
#16
I have no complaints. Next time I have the covers off I need to pull some rockers and make sure I'm not getting abnormal wear on the valve stem tips or anything.
I wish I could accurately describe how different it feels to drive than before. The way power comes on is both more intense but smoother at the same time. It's not uncommon for LS engines to have massive power spikes above 4,000rpm but this is even more different than that.
The absolute best though is when I'm tearing up mountain roads and letting it hum along a sweeper at 4,000-4,500rpm then on corner exit rolling quick to WOT and the car just explodes out of the corner. It feels insanely quick how fast it revs from 5,000 to 7,000. I took some videos but they don't look as impressive as it feels in the car.
A friend who is very familiar with my car and has ridden in it many times was riding while I was working on the tune right after the LLSR cam went in. He decided to pull my old Cam Motion 230/238 from his LS1 and order a LLSR for himself. IIRC he didn't even change his cam specs, just got an equivilent duration and LSA but Kip maxed the lift to the limits of the springs since he is using adjustable rockers.
The only limit to the stock rocker method is the lift...too much and it can cause issues. Mine is in the .635" range. My friends is in the .670" range.
I wish I could accurately describe how different it feels to drive than before. The way power comes on is both more intense but smoother at the same time. It's not uncommon for LS engines to have massive power spikes above 4,000rpm but this is even more different than that.
The absolute best though is when I'm tearing up mountain roads and letting it hum along a sweeper at 4,000-4,500rpm then on corner exit rolling quick to WOT and the car just explodes out of the corner. It feels insanely quick how fast it revs from 5,000 to 7,000. I took some videos but they don't look as impressive as it feels in the car.
A friend who is very familiar with my car and has ridden in it many times was riding while I was working on the tune right after the LLSR cam went in. He decided to pull my old Cam Motion 230/238 from his LS1 and order a LLSR for himself. IIRC he didn't even change his cam specs, just got an equivilent duration and LSA but Kip maxed the lift to the limits of the springs since he is using adjustable rockers.
The only limit to the stock rocker method is the lift...too much and it can cause issues. Mine is in the .635" range. My friends is in the .670" range.
Last edited by thunderstruck507; 08-09-2016 at 10:17 AM.