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Hey, im looking at getting some bigger cams for my r33 gtst and i wanted to upgrade the valve springs while im doing it.

The cams im looking at getting are:

HKS 256 8.8mm lift on the inlet

HKS 264 9.0mm lift on the exhaust

I wanted to get the tomei valve springs but they say they are for 8.8mm lift only. They have another set which is 10.25mm but its for solid cams only. Now i know that if i go too hard of a valve spring you can damage the valves/valve seats so i want to know what the best combination is.

Also, I was wondering if i would be better off going for a solid cam setup?

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I'd like to know the answer to this aswell.

You doing any head work while putting the cams in? I've heard that making the exhaust side of the head slightly bigger and putting in some oversized valves gets good results. I think the RB25 Neo's have the slightly bigger exhaust ports and valves.

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Why a larger exhaust then inlet?

Apparently the exhaust valves on RB engines are a bit small when running big boost and it helps this problem a little by having more duration on the exhaust cam.

Anyone know anything about which valve springs to use?

Mike.

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Does anyone have anything constructive to add?

Or does anyone know if tomei valve springs will be ok for cams with 9mm lift

Tomei springs would be fine but Spoolup is on the money. I think he has them bloody cheap too!

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I thought I was being constructive.

I have used Performance Springs in three different engines and never had a problem. Current engine turns to 8000 rpm everyday - numerous times.

Does anyone have anything constructive to add?

Or does anyone know if tomei valve springs will be ok for cams with 9mm lift

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yea i was wondering y u have bigger ones on exhaust?!?!

on nengun they do that too. but thought it was a typo. wouldnt it be better to run 2 of the bigger sized ones. instead of 2 cockeyed sizes??

fyi...any springs out of the nengun catalogue is sweet.

their tomei springs are pretty cheap at about $400, same with solid lifters.

if your going bigger cams dont leave home without them

Edited by r33cruiser
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I thought I was being constructive.

I have used Performance Springs in three different engines and never had a problem. Current engine turns to 8000 rpm everyday - numerous times.

Hey mate, sorry about my comment, when you said "Performance Valve Springs" i thought you were meaning any brand is good. I didnt know there was a brand actually called 'Performance Valve Springs".

How do i get into your website, it doesnt seem to be working. Would you be able to PM me a price on the valve springs.

Thanks for your help,

Mike.

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i thought u didnt even need valve spring upgrades for 9.0mm lift????

isnt 9.0 a step 1 cam shaft?

Im not too sure if they are step 1 cams, but im pretty sure its recommended to change the valve springs.

The tomei poncams 256/256 8.8mm lift dont require the valve spring change, but its probably better to change them anyone to avoid any valve bouncing issues etc.

Mike.

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...on nengun they do that too. but thought it was a typo. wouldnt it be better to run 2 of the bigger sized ones. instead of 2 cockeyed sizes??...

Going big on the intake as well affects idle, low end, emissions etc, whereas big on exhaust seems to reap benefits without so much negatives.

As mentioned RB's have reasonably poor exhaust port flow (comparatively to intake)

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Going big on the intake as well affects idle, low end, emissions etc, whereas big on exhaust seems to reap benefits without so much negatives.

As mentioned RB's have reasonably poor exhaust port flow (comparatively to intake)

Agreed.

I'd be going HKS 256 on inlet and HKS 264 on exhuast with slightly oversized exhaust port, and that's what i will be going with in the future :banana:

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can anyone confirm if the neo do indeed have larger exhaust ports/valves? Are they bigger the the rb26? Im getting the performance springs installed along with tomei 260 cams. Is it the rpm or hp that start to cause issues with aftermarket springs? It has rb30 bottom end, 8k rpm limit and t04z with 2bar. And spoolup can you confirm what material is used for the NEO lifters?

cheers

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