Guys, i need a little advice about my cams. You may know by now that ive turbocharged my SR20. At present, im running with some custom piper cams, but i dont know the degrees theyre machined at. If anything, its gonna be better than the stock ones. Trouble is, some performance cams will give you rough idle, like these do, so i was thinking of swapping the stock GT cams back in for the turbo setup.

What do you think?
Stick with these custom jobbies?
or Stock cams?
Will the stock give detonation problems?

if the custom cams are too rough or harsh try the stock DE cams....either way you will not have "optimal" cams for a turbocharged motor. If you can at least get a stock set of BB/avineir cams that would be better (powerwise) than your stock cams and better than the custom cams (idle wise). Or get some aftermarket DET cams with 256* duration

bluebird cams are the exact same as stock. IIRC, 10:1 primera cams have 1 more degree duration as well. Asa general rule, people tend to stay away from regrinds. What computer are you running?

My JWT C1 cams would kick ass. :)

P11: you have a roller motor, don't you? This means your options are either stock, some crazy custom grind, or JWT Roller S3s (the only aftermarket roller cam in the US, anyway). Tomei or somebody JDM may have a roller grind, but I've never heard of one. S3s are kick-ass cams on our heads, though, and the non-roller version has been shown to pick up 30+ WHP on otherwise stock Bluebird DETs.

Adjustable sprockets, in this case, are hardly optional, as you really need to dial the overlap out of the cams as much as possible for a turbo application. JWT didn't do a great job of optimizing the roller S3s anyway, so dyno time will be absolutely necessary to figure out where the cams need to sit.

If I have you mixed up with somebody else, and you have a non-roller head, you can also get JWT S3, S4, or C1 cams (mildest to roughest idle), which are extremely good for turbo engines. With the S3 or S4, all you have to do is dial out overlap, and you're good. I have no ideabout tuning C1s, but it shouldn't be much different. S4s are about as wild (lumpy) as you want to get on a street car, but that's not to say C1s are uncivilized; they just idle a little rough.

JWT S3, S4, or C1 cams (mildest to roughest idle)
i thought the C1 came between the S3 and the S4? I think the S3 has 260 or 262 deg, C1 264deg an S4 266 deg
but i may be wrong

S is for Street grind. C is for Competition. S4s are orders of magnitude milder on N/A engines than Cs are. I don't know specs, but I know intended uses, and C1s are not intended for daily drivers, while S4s are.

Cowboy, youre spot on, mine is infact a roller SR20. i feel that this has limited my options a bit. I was looking into the GTiR cams, but as you know, the GTiR Sr20 was never roller either.

So in theory, i could keep using these piper cams, and just get some cam gears to adjust them so they dont overlap? right? that might be the best option. Only trouble is, it will take ages to setup on the dyno thats for sure. I have a hard enough job trying to book the car into the dyno shop, let alone getting it tuned.

Yeah, I was just thinking that adjustable sprockets could make your cams more livable. You'd need a day to tune on a local rolling road, though, as adjusting sprockets on an SR20 is no easier than doing a full cam swap. Sad, but true.

One thing im worried about, is you know the VC bolts, well after 4 cam swaps now, the thread are starting to break a bit. Some of them arent even set to the correct torque. I need to look into re-tapping them and using slightly oversized bolts.

Now you got me thinking of going for the roller S3 and gears, im really stuck in a hole here.

I rang up Piper Cams this morning and heres the spec on the cams they made for me. How do these compare against JWT, Tomei etc?

Intake Cam, 258* valve lift 364 thou (9.24mm)
Exhaust Cam 248* valve lift 331 thou (8.41mm)

With the turbo, you just want to make sure you don't have too much overlap.

As for the cam specs, well, there are listings for the non-roller cams.... duration is duration but I don't know if you can compare the lift.

I would think one of the japanese companies would have cams for your motor. I mean, they sell your car over there too (I think!). So maybe JUN, HKS, Toda.

Khiem

Re your VC bolts:

I wouldn't got the trouble of tapping them bigger and risking getting the shavings in the head. Just chase the crud out with a tap, shoot some brake cleaner in the hole, and epoxy the bolts in. Epoxy is holding a head bolt on my dirtbike ;)

Cheers,
Charlie :)

Cool tip, thanks. Is removing them gonna be a problem? or do you just do the samething next time you want them back in again?

Lets start from the beginning before we get into this to far! What turbo do you have? Is this on a 10:1 motor? The S3 cams I am not sure but I thought were 264's and the s4 cams (I am positive) are 268. I do not know how the C1's but I would imagine that they are bigger. I have not adjusted the S4 cams on my car with a T28 setup and the numbers that came out are below. The idle is not as lumpy as it was when the car was N/A! But I am wondering what the specs are on the cams you have in the car now? Thanks

I am 100% sure that C1's have less duration than S4 cams. Since they use stiffer springs and Ti retainers, they can have more lift despite the reduced duration

Originally posted by MarkSR20
Lets start from the beginning before we get into this to far! What turbo do you have? Is this on a 10:1 motor? The S3 cams I am not sure but I thought were 264's and the s4 cams (I am positive) are 268. I do not know how the C1's but I would imagine that they are bigger. I have not adjusted the S4 cams on my car with a T28 setup and the numbers that came out are below. The idle is not as lumpy as it was when the car was N/A! But I am wondering what the specs are on the cams you have in the car now? Thanks
The spec on my car is here. (http://www.primeragtp11.pwp.blueyonder.co.uk/newspecx.html) To cut it short, its 8.3:1 compressionn with a T25/T3 setup with 8psi boost.
Now these Piper cams ive got in now, were actually ran before i turbo'd, even then, they seemed s bit lumpy at idle. Now that it is turbo'd, im experiencing a bit of detonation, which is currently kept in control by water injection. My aim is to run about 10 or 11psi boost, when ive sorted out the bigger injectors and other fueling issues. Im just wondering if its worth selling these cams and get sometime which is more suitable for more boost/performance, or just get some cam gears to dail out the overlap.

The spec on the Piper cams are as follows.
Intake Cam, 258* valve lift 364 thou (9.24mm)
Exhaust Cam 248* valve lift 331 thou (8.41mm)

Actually Cowboy, the C1's are more civilized than the S4's. THey idle like stock on my car and have no loss in low end.

Mark: So you have a Bluebird DET with a GTi-R exhaust manifold and T28, with JWT's S4 cams installed, but otherwise stock? I want more information! :D

fast/Terrin: I'll accept the correction. I'd heard negative things about C1s in N/A situations, though, which may or may not be reliable, and may or may not apply to this discussion. I stepped out of line, and apologize.

Ive finally decided on getting the JWT S3 roller cams and gears. Ben Pila gave me some good advice.

Thanks for the help y'all