LSA plays a big role in forced air setups, cams very much designed for NA operation, generally leave room for big improvements, with the VE cams available, its a noticeable value, especially if someone were to for some silly reason try using the N1 cams, they were the worst from what I saw for a forced air setup, combine bigger lift and duration, as well as no great spot for the angle on both the high and low side you end up with a LOT of overlap.

Yes Jr, you can get them reasonable with just cam gears on the P11 cams, the P12 pair just offered a much closer to that of stock and aftermarket, figure. I had a whole bunch of numbers a while back calculating the possible combinations, using the different available cams and retard/advance of available cam gears, but I guess its gone now.

 

S13 SR20det has 119.5* LSA

S14 and 15 have the same, but the timing is actually different due to different centerlines on each.

Stock GTIR 115 LSA

Stock P11 would have 116 on the low side, and then jumps down to a 109 LSA on the high side

P12 have a 110 low, and 111 high, so with gears you'll get them both being in a similar range, where the other cams you either get the low side good, and the high side bad, or vice versa.


Keep in mind generally 112 -114 lsa ends up on most street stuff with a NA setup, 114 being smoother idle and the lower lsa being choppy and for those after max power, NA, then the lower stuff 110 and 108 range again higher rpm NA power, really not going to be ideal for a turbo setup, where most want the lsa 114-118,


JWT S cams have a 114 lsa
JWT C cams have a 112 lsa

JWT c6M, designed for high rpm, NA, high comp, and specifically listed as "no low rpm driveability" 109 lsa

Of course thats just LSA's, the real fun comes after you factor in the duration on them and actually get the overlap.

 

S13, 14, 15 DET overlap 1*

GTIR 18*

JWT S3's 32*
JWT S3 38*

Tomei 260 35*
Tomei 279 45*

P11 Low -12*
P11 High 48*

P12 Low 16*
P12 High 57*

 

This is the first time I've seen all of this data in one place. Can you add some info about S14/S15 with VTC activated/disactivated? 20* is unaccounted for in your numbers. How about the S14/S15 DE/DET comparison to make this more of a learning experience for everyone.

Also, the idea of going with N1 cams on a boosted car might spring from the word that Mazworx used them on their million hp SR22VE. Of course, that car only operates at high rpm / high boost, so the cam gears are probably optimized as such. It would only need to idle on the low cam, and even that can be cheated by raising it.

 

Here is the chart I used for my stock data chris

Factory Camshaft specs

You can see where the 14/15 cams vary from the 13's

Heres the data on the JWT's

http://www.jimwolftechnology.com/wol...ECCARDSR20.pdf

Heres the data on the tomei's

Camshaft

 

S13 DE overlap is 10*

121.5 lsa

S14DE is 1* overlap

I guess on a S14det with the cam completely advanced it would have a 109.5 LSA, and 21* of overlap with the cam fully advanced. pretty close to the gtir's 18*

 

So finding a set of P12 cams ideally would be the best route to go once they were timed in correctly? I plan on purchasing cam gears for this build anyway, but what would I be the cons of setting them up for high lobe and leaving the low lobes out on the P11 cam's? Choppy idle? not wanting to idle? The gentleman that had this before had a solid idle and made great power without cams gears, although both his motor and head were untouched. I believe my block was milled .010, but I can't be sure. I will be running a 1.5mm head gasket to accommodate that material being removed. My biggest concern is valve to piston clearance, if I can find some P12 cams I'll slap them in from the get go.

 

I'd probably just put it in, or adjust things a little bit with the gears on the p11 cams to be honest.

 

Though I really wish I still had the files, I had numbers for each of the configs, with adjusted figures using cam gears, and then combinations of different available VE cams.

 

Well, either way, it would still be nice to find some P12 cams for future testing. I'd like to get this setup running first though. Thanks for all the information Z28.

Back to the build, haven't done much because I was on a mini vacation at an island resort. I'll get back to it this week.