Speed si5v2 vs. si5
10-31-2012, 05:41 PM
#1
Speed si5v2 vs. si5 Hi, I have a 01 a4 trans am an I wanna do a cam swap I have been looking into a couple of cams.... Speed inc si5 and si5v2.. I am going to be doing full exhaust 3.73 gears and all new valve springs and retainers push rods pulley fuel pump injectors oil pump and trimming chain with 3k stall. My question is do I need new heads if I go with these cams or can I just built them stronger? Oh and I have la6 intake. Quick responses would be nice want to do it within the next month thank u
10-31-2012, 06:02 PM
#2
TECH Resident
im probably going to go with the SI5 for mine... Speed Inc hasnt had any proven numbers with the v2 yet and the one i saw they put on a dyno actually made less power i think
11-01-2012, 12:34 AM
#6
TECH Resident
his mods were:
PRC stage 2.5 ls6 heads
Speed inc si5v2 cam
LS6 intake
36# injectors
SLP Lid
SLP underdrive pulley
Hooker 1 3/4" Lts ORY loudmouth II
! Air pump
! EGR
3.42 gears
6 speed
this ones mods are:
Stock LS1
stock 241 heads
Speed Inc SI5 cam
36# injectors
lid
ls6 intake
Pacesetter Longtubes
3.23 gears
4l60e trans
So how i look at it... the regular SI5 made better power with less mods and through an auto.. with an underdrive and some 5.3 heads id expect about a 20hp boost and possibly get to 450 wheel
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11-01-2012, 12:42 PM
#13
TECH Resident
all i was trying to show is a stock longblock car with an auto made similar numbers at all RPM's and more torque under the curve than the larger cam with better heads and other mods through an M6... you can argue Dyno to dyno and i will agree with you... but ive seen the version 1 with the same mods as the top dyno push out 450hp and 405tq....
im personally going to go with the version 1...
ill also go with some Livernois double springs.. (.690) much more than i need yes but they are the same or cheaper than the other .650 springs i can find so im going to go with those...
your also going to need Chromoly pushrods and if i were you i would put in these to be safe and have added insurance.
LS7 lifters
LS2 timing chain
HV or ported oil pump
for the smaller cams like this im going to run some 5.3 heads. they will bump your compression to 11.0:1 and the low end power increase will be nice... since these cams arent high revving the smaller valves shouldn't choke it out much
im personally going to go with the version 1...
ill also go with some Livernois double springs.. (.690) much more than i need yes but they are the same or cheaper than the other .650 springs i can find so im going to go with those...
your also going to need Chromoly pushrods and if i were you i would put in these to be safe and have added insurance.
LS7 lifters
LS2 timing chain
HV or ported oil pump
for the smaller cams like this im going to run some 5.3 heads. they will bump your compression to 11.0:1 and the low end power increase will be nice... since these cams arent high revving the smaller valves shouldn't choke it out much
11-01-2012, 01:46 PM
#14
And all we are saying is comparing dyno numbers from different cars and different dynos doesnt mean ****. Dynos are tuning tools...what you are doing is stating your opinion but discrediting a sponsor who puts hours of r&d into their products. I'm sure if there wasnt something to be gained by the Version2 cam, speed inc wouldnt market it at all in favor of what works. Apparently, it does something better than the original cam or it wouldnt be available. Just because there isnt a bunch of people using it yet or a bunch of dyno numbers for it, doesnt mean it isnt as good or better. If everyone used your logic, no one would ever buy a custom specd cam because there isnt many people using that specific cam and not enough dyno numbers saying its good...
11-01-2012, 01:51 PM
#15
OP...If you are sticking with a 3k stall, you may want to rethink the size of your cam anyway. With a 231/237, i would think at least 3400-3600 stall would be ideal...if you already have the 3k stall, maybe you should look into something the size of a 224/230 comp cam, or a 224R sized cam...
11-01-2012, 03:07 PM
#16
TECH Resident
IM NOT DISCREDITING A SPONSOR...
most of the cars run the SI5 v2 in an LS3 car... most 5th gens make 440 wheel with one...not much proof that its better in a stock cube LS1.. they have the same specs the v2 just has a little more lift... .589/.595 vs .617/.607
So far 1 car with it and didn't out-perform regular SI5 cam in a 346, then again some cars dyno 390rwhp and 425rwhp with same cam and drivetrain combination, so i'd like to get more real world numbers from it.
Had higher expectations, maybe in the next combination i'll see them?
Had higher expectations, maybe in the next combination i'll see them?
most of the cars run the SI5 v2 in an LS3 car... most 5th gens make 440 wheel with one...not much proof that its better in a stock cube LS1.. they have the same specs the v2 just has a little more lift... .589/.595 vs .617/.607
11-01-2012, 06:51 PM
#19
Those .690 lift springs might not be the way to go. Bigger isn't always better. It's all about seat pressure with springs. Running those on a sub 600 lift might not be the best choice. I'd look into that, I may be wrong but its worth checking the specs on those springs...