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What Cam Choice Should I Go For

Devils_Advocate21
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Devils_Advocate21 Mentor

Devils_Advocate21

Posted
Posted

Ok Ill cut straight to the chase i have searched and i swear there was a thread on camshaft choice vs turbo i could be imagining this, im after some next stage engine mods to increase power and be very benefitial for my result.

So far ive come to an end of where to go to increase power in my setup.

Major details:

RB25det

Forged Pistons Rebored to rb26 size rebuilt bottom end mild pnp head and full head service.

Turbo: Hks 3037pro S IW

Inj: Nismo 555 cc injectors

Driveline: Supporting mods for this running on standard gtst diff including a better clutch to handle the power

Running splitfires

Apexi PFC

G-reddy EBC tuned to 16.5 psi

Tomei 248 Lp/h Fuel Pump

FMIC

Apexi Pod

Exhaust: Custom Split dump to highflow catco cat to 3.5" back

The tuner recommends either cams or New plenum both of which he says will increase over power figure that i have

At the moment 221 rwkws with 1561 N.M Torque on dynologic dyno. With wheel spin?

I want to increase this a fair bit and i find that cams are probably the next step, But with what choice should i go in regards to turbo and engine setup. Either tomei 256 in/ex 8.5 Lift or hks setup both choices either 256 in/ex 8.8 lift or combo it with the 256 in 8.8 lift and 264 ex 9.0 lift. Which would give my setup the benefit of best result. Hence im after some input here, On that note with plenum would it increase power or is that a fad? I have seen results seen past 300rwkws im saying will it increase power not will it handle the power.

Just some recommendations and ideas would be good on what path to take here

Cheers Guys

Adam

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subzeroR33 Mentor

subzeroR33

Posted
Posted

Well i had the full rebuild and ran out of money when it came to the cams.

It has a custom plenum and the rest.

Running around 450rwhp with standard cams.

personally you are paying for the name when it comes to hks.

I have noticed that you can pick up a set of tomei cams for $750 on ebay, which will do the job fine as i have heard good reports on the tomei cams.

BHDave Grand Master

BHDave

Posted
Posted
personally you are paying for the name when it comes to hks.

On an s1 rb25 you are paying for the extra lift and duration on the exhaust side. Or you can rip the head off and get bigger exhaust valves put in and use tomei's which don't offer anything other than a 256 for an s1 engine.

Id recommend hks 256/264 from experience with an otherwise internally stock engine. I initially went from 238-268rwkw with no other changes by installing these cams with a similar size turbo to yours.

I'm now making 288rwkw just from freeing up the exhaust some more after the turbo.

GTshortie Proficient

GTshortie

Posted
Posted

Taken from another post about camshafts by URAS:

yeah but zero on the gears is not often zero on the cams, HKS especially need dialling in to get a "real" zero. some supra ones i used on this car a few years back were ~4 degrees out.

Questions:

-Does that mean for a rebuilt engine with lower/higher compression setting the tomei cam shafts to '0' degrees would not get the best results as that for a internally stock engine?

-Can you adjust the camshafts setting without an adjustable camgear?(or do you have to purchase adjustable camgears to adjust them)

-Any guys on SAU with a rebuilt lower compressioned RB25DET running aftermarket camshafts? What gains/results have they got?

Devils_Advocate21 Mentor

Devils_Advocate21

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Posted

I was also led to believe the 256/264 combo is a good option, Im guessing a little playing with the dialing for these would needed because of mismatching? But as you said SK tomei seems to be the way to go?? Bah i wish i had a little more on this can others state results on similar setups and experiences? SK have you tried the 256/264 combo on any of your engines, just wondering how you went if you did and if there was much if any dialing needed setting for this type of combo?

Cheers Guys

A

rev210 Grand Master

rev210

Posted
Posted (edited)

After a little research I went for just a HKS 264 on the exhaust side with a standard inlet for an old R33 gtst. It proved very effective on a mild engine , stock turbo & intercooler. I have attached a graph of the 'after' of a run in tune for my old car. The shape is a little different to what you expect from the stock cams.

This tune was mega conservative on timing(run in tune) and low boost (6 psi) 175rwkw at 5,500 (the top end power was tuned off on purpose). This was a stock turbo + intercooler + SAFC II. Afterwards the car was tuned to make the better part of 180rwkw by around 4,000rpm @ 10psi for the new owner. The car came on boost very hard, I estimate it would have made around 200rwkw by 5,500rpm on the same boost with a Power FC and some more tuning. The guy who bought it had not owned a performance car before and wisely took my advice to leave the power where it was till he got used to it. It's a shame I don't have that dyno graph anymore. And I lost touch with the guy who bought it.

I would certainly vouch for the tomei offering for 3037pro, more than the smaller stock turbo it will really wake up with a decent size of cam on both ends. If you decide to squeeze more top end out then with higher RPM a set of beefy valve springs to go with them is a good move too.

Do get some cam gears for them all the same since we have new fuel offerings being made availible (like the ethanol variants) which you can capitalise more on with an appropriate adjustment to cam timing.

post-271-1174380319.jpg

Edited by rev210
Devils_Advocate21 Mentor

Devils_Advocate21

Posted
  • Author
Posted

Thats what i thought, tomei seems to be the win so far, but wouldnt mind a little more input based on the hks combos as im guessing would work on the same principle but if it is say shown that it is a better selection vs tomei that the way i will go but if it needs improvement compared to tomei ill go that way??

Cheers

A

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