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This is a statement from Aaron at ER regarding S1's vs S2's:
"I have not noticed a difference as far as increased spool in any of the many GSC cams we tune. S1 over stock makes more torque literally EVERYWHERE and power as well. It looks like the powergraph gets lifted straight up. The S2s dont lose over the S1s but normally really pick up out the top only. Out the top is subjective but we'll say something like 6k. This is why we normally suggest S1 for cars that are road raced and S2s for drag cars. Drag racing is almost always over 6k, road racing varies ALOT."
he told me that if running MIVEC there is no point going smaller than s2..
.... I can compare it only to stock turbo with kelford 264 (which I would avoid as they are noisy and did not produce any measurable improvement on stock turbo), but I have a friend who has a 7460 HKS on a stock 2.0 with HKS cams (which are slightly smaller than S2) and there is no real difference in spool...
As for real transient response, I did measure it on the 7460 / S2 car, and it will go from zero throttle to 1.8 bar boost in .5 sec at 4500 RPM.. We will measure this in more detail when my personal car with EFR 7163 is done..
as for the S2 and HKS (which is not the point of this disscusion but is similar sized to FP71)
this is full throttle in 3rd gear at 2500 RPM.. check the boost log..
it would probably spool sooner with more fuel down below..
well it looks like I wasted $500+ on a set of cams that are uselss
Nah, from stock to S1's (non-mivec) I picked up 8mph and dropped 0.6 seconds in the 1/4. Stock all stock except cone filter, o2 back exhaust and tuning ± s1 cams. from 12.9 @ 105 to 12.3 @ 113mph. stock piping, stock 9.8 VIII Turbo and stock o2... Had to change my timing and fuel maps a good bit as well with the swap. Whoever says they're useless is crazy.
I'm installing a bb red this weekend with the S1's so I'm pretty stoked about that.
Nah, from stock to S1's (non-mivec) I picked up 8mph and dropped 0.6 seconds in the 1/4. Stock all stock except cone filter, o2 back exhaust and tuning ± s1 cams. from 12.9 @ 105 to 12.3 @ 113mph. stock piping, stock 9.8 VIII Turbo and stock o2... Had to change my timing and fuel maps a good bit as well with the swap. Whoever says they're useless is crazy.
I'm installing a bb red this weekend with the S1's so I'm pretty stoked about that.
I'll soon be doing a set up very similar to yours and am anxious to see the results.
Evo 8.5- stock block/cams
HTA 71 (stock cold size housing)
Muse 02 dump
Evo 9 crushed DV tested to 32 PSI
3 inch DP
3 inch full exhaust
Grimspeed 3port EBC
FIC 1250
DW 300 fuel pump
Speed Density
Omni 4 bar
ETS upper and lower pipes (stock battery routing)
Debating on the 84mm FP cover, stock evo 9/ turbo smart WGA.
Hoping to get close to 400 pump and about 420 E85
Anything mods you regret doing or would change if you could start over? Sounds like surging is your biggest issue?
Took me 3 days but lots of great info. I'll attach mine so we can all see how hta71 is so consistent! My mods are:
Injen intake, LICP, & UICP
3" TBE with HFC
HTA71 w/84mm
RC 1200mm injectors
AEM 320 LPH fuel pump
AMS FMIC
3-Port boost controller
Self ported stock exhaust manifold
Self ported 10.5cm hot side
MAP O2 (I touched up to match my hotside)
Fully crushed DV
Stock IX engine,TB, head studs, cams, WTA,
I think I'm on par with everyone else (I was on the lower end with my previous setup)
E85 is AMAZING!
Boost looks good, but now I wonder (from reading this thread) if my stock WGA couldn't hold more on top than 24 psi.
Curious if others have pictures of their ported exhaust manifold, hotside, or O2. I wonder if that helps much.
Last edited by 2006EvoIXer; Jun 17, 2017 at 09:14 PM.
I'll soon be doing a set up very similar to yours and am anxious to see the results.
Evo 8.5- stock block/cams
HTA 71 (stock cold size housing)
Muse 02 dump
Evo 9 crushed DV tested to 32 PSI
3 inch DP
3 inch full exhaust
Grimspeed 3port EBC
FIC 1250
DW 300 fuel pump
Speed Density
Omni 4 bar
ETS upper and lower pipes (stock battery routing)
Debating on the 84mm FP cover, stock evo 9/ turbo smart WGA.
Hoping to get close to 400 pump and about 420 E85
Anything mods you regret doing or would change if you could start over? Sounds like surging is your biggest issue?
.... I can compare it only to stock turbo with kelford 264 (which I would avoid as they are noisy and did not produce any measurable improvement on stock turbo), but I have a friend who has a 7460 HKS on a stock 2.0 with HKS cams (which are slightly smaller than S2) and there is no real difference in spool...
