S13 turbo cams...2 exhaust cams?!?

[encasemyheart]

Hey,

I was on unstable-hybrids.com because I'm about to order the 50lb injectors and fuel rail and noticed Dennis' S13 240sx that made 350whp. What astounded me were the mods, no internal work at all, no tuning aside from a JWT ECU!! I thought that was awesome. All on 50lb injectors. So to verify, I emailed for exact mods, here's what I got:

Sorry for the delay. That run was at 15psi, with a T3/T04E, 50 trim compressor in .50 A/R, .63/Stage 3 turbine, RevHard manifold, JWT ECU, etc. No additional tuning, no head work, no bottom end work, only cam change to 2 S13 exhaust cams. That was the 3rd run of the day...I made 350rwhp on the previous run at the same boost level...but they had the dyno set up incorrectly and so the torque number was incorrect...so the only graph I have with a torque curve is that one.

Which is wonderful because it's the exact same setup I will be using (which is why it interested me so much in the first place) I assume the 15psi was on race gas, but I will be running 12psi on 93 pump gas same setup.

Anyways, what's with having 2 exhaust cams? What will it do for the power? Will it help N/A applications at all? Will the other exhaust cam fit without modification into the intake slot? It would be very easy to pick one up at the junkyard, there are 240s everywhere.

[JJ240]

S13 exhaust cams have higher lift and duratino than the intake cams. 1993 being the highest lift and duration cam. I dont remember exactly what the specs were, but i think its 248/248. If you find one from teh junkyard you have to have it repinned because the key pin to align it with the cam sprocket is set for the exhaust instead of the intake.

[:: orion ::]

Need to clear a few things up:

S13 cams have the same lift, but longer duration than S14 cams.

S14 cams are 232 degress on the intake and 232 on the exhaust: 232/232

'91 and '92 cams are 240/248...

'93-94 are similar if not identical to S14 cams.

So the stock 'upgrade' cam for your S14 would be any '91-92 cam set.

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What Dennis is using replicates the Nissan Motorsports USA Cams (i.e. not NISMO...) - They are 2 stock '91-92 exhaust cams - One used as an exhaust cam, and one re-pinned for use as an intake cam. Dennis replicated this by using 2 unmodified S13 exhaust cams and just moved the cam gear over by 4 teeth on the intake side. So the intake cam is almost dead on, but I think it's retarded by 1.7degrees IIRC...

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On an N/A application, it's good for 8-10rwhp over stock S14 cams...A friend here in town made 160rwhp with I/H/E and the Nissan Motorsports USA cams. He did lose some low end, as would be expected. His car is A LOT of fun to drive, though...before it felt flat, now it likes to rev to the limiter and still pulls. He's run a best of 15.2 at 92.5mph with a full weight S14 with this setup...

- - - - - - - - - -

In my S14 I run just a pair of stock '92 cams, and it makes a decent difference - I'd say maybe 3-5rwhp, but the power starts to fall dramatically at 6200 instead of 5800 as it does stock. It basically shifts the HP curve over to the right by 300-400rpm, and the car is smoother in the higher RPMs and likes a rev a little more.

Later - Brian

[:: orion ::]

Here's the link to the Freshalloy.com thread with A LOT of info on this very topic:

Freshalloy.com S13/4 Cam Thread..

[C-Kwik]

Which is wonderful because it's the exact same setup I will be using (which is why it interested me so much in the first place) I assume the 15psi was on race gas, but I will be running 12psi on 93 pump gas same setup.

I believe he made that run on pump gas. I've heard of several haveing run 15 psi on pump gas with stock internals. All were running a 50lb injector set-up with JWT.

[encasemyheart]

Ahh, thanks for the correction. IIRC 350whp is right where the pistons will start giving out, correct?

[encasemyheart]

I read the FA thing, thanks for the link. SO all in all, it seems like something that really didn't do too much powerwise and something that is really hard to do because you "have to be able to accurately measure cams."

EDIT: After reading it seems easy with the "4 teeth method." I may try this, couldn't hurt and I can get a cam for CHEAP.

[JJ240]

KA24DE is an interference engine. 2 teeth off and you will have valve to piston contact. Yes I know from experience.

[midnightsliding]

dose anyone have a website that tell me how to do this step by ste or andthing close to itthanks