__jb

iTrader: (3)

How many miles do you have on your motor?

Valve springs don't last forever. If I was going to all of the trouble of putting new cams in, I'd sure get a set of valve springs designed for those cams... especially if you're thinking about revving the motor higher... especially if the motor has a lot of miles on it.

Chef-J

iTrader: (58)

What headers and intakes do you have?

KA24DE

No they don't, but I sure as hell wouldn't put new, stiffer valve springs in just because. Regardless, the cost of them is actually minimal compared to the price of the cams themselves.

nismology1

I would upgrade the valve springs if the engine will be seeing > stock redline with an aftermarket cam. You want to err on the side of too much spring pressure than otherwise.

__jb

iTrader: (3)

I'm not suggesting that.

I'm saying that if your engine has a lot of miles on it, the valve springs are likely fatigued. Putting a new set of valve springs on that are designed for the camshafts you are installing is worthwhile.

That doubles if you plan on revving the engine past the original rev limit.

OCG35

iTrader: (2)

just under 39K

I have commited to springs (JWT) and either OEM revup, Nismo or ARP rod bolts - undecided on staying at 7200 or going to 7500

OCG35

iTrader: (2)

I concur

OCG35

iTrader: (2)

will be Crawford headers (unless Z1 makes huge progress on his long tubes anbd goes production wiht them)...

I have a G... Stillen intake with Z tube, machine upper & lower plenum and 1/2" spacer...

Chef-J

iTrader: (58)

Agree with this.

Chef-J

iTrader: (58)

I'm at under 50K, hopefully can do install cams/springs after this winter. But i will not bother rods/rpms for now, untill i build new engine.

OCG35

iTrader: (2)

just the rod bolts... not the rods themselves... pre rev-up have proven to be less tolerent at higher the OEM (6700) rmp... not a risk I'm willing to take even at 7200... a failed bolt = thrown rod.

Chef-J

iTrader: (58)

oh my mistake, i thought you were talking about rods themselves.

OCG35

iTrader: (2)

originally I was... in fact, until further research I wasn’t certain the OEM rods themselves were decent for my quest...

The bad thing about these forums is - boatloads of research sometimes isn’t always summarized in the same starter thread... sorry - I am trying to keep my meager attempt at a certain goals documented here (but as I learn stuff, I don’t always correct my original questions)

Trust me, I realize others have gone down similar paths - but I know of none (NA G sedan) that has attempted the ideas I have... I've had multiple conversations with various involved parties so I hope the questions here don’t come across as completely blind attempt at something foolish...

Theoretically what I have in mind will result in decent gains with minimal risk. That’s the whole idea. Oh and the four door shocker comes into play a bit (it already has in many cases )

OCG35

iTrader: (2)

KA24DE... thanks for the mention of upgraded oil pump... initially I figured it was added pressure or added volume (neither of which I need)... I have since found that the Rev-Up oil pumps center collar (whatever its called) that drives the pump from the crank shaft - is actually stronger than pre rev-up... the pump itself is virtually the same - just the assembly that the shaft runs through is stronger...

So I went ahead and ordered one.

FWIW, all I'm doing are mild cams (JWT S2) and Crawford headers and plan to rev to 7500... I'm using JWT valve springs, Rev-Up rod bolts and Rev-Up oil pump as precautions...

So thanks again for the suggestion (even though I was thinking it was for a different reason initially).

Chef-J

iTrader: (58)

^ hope it turn out nice. Good luck

__jb

iTrader: (3)

Are you going to install the rod bolts with the motor in the car?

I wonder if the new rod bolts will weigh the same as the OEM rod bolts.

copec

According to my calculations from some manifold design books I have, the stock manifold's area in combination with the bends adds significant impedance to the wave activity about 6000 rpms on up or so. So i'm going to go ahead and suggest that you get your intake manifold extrude honed, like from http://gethoned.com/ and have them do more then just the resurface honing, have them open up those ports. Or ported from an experienced individual. I think you could then outdue the powerband from an HR motor.

I think the ye'expirienced machinist that worked over Z1's motor really knew what he was doing to the intake manifold and heads, and thats the major reason he makes so much power so long and so high. Of course that in combination with the right other parts...

I'm a poor college student right now and I want to see if this adds any significant gains so you should guinea pig it for us :-)

OCG35

iTrader: (2)

thanks
It’s an expensive proposition (but so has everything else I've done to the car)... Even if there are decent gains it obviously wont be the best bang for the buck - but another yippee (hopefully) for those of us that enjoy the painful route of NA gains.

I’m quite certain there wont be any NA AT sedans that will beat it (already aren’t that I know of)… and hopefully it will limit further the number of MT (currently only a few).

OCG35

iTrader: (2)

I'm not doing the install myself... I've been in talks with 2 (well known) shops... one would do everything form the front (removing front end including core support)... the other would actually remove the motor (making the header install as well as cams, springs, rod bolts, etc. easier)... I'm 99% on the shop that plans to remove motor (for various reasons - primarily that they have been very helpful with questions and they have done other work on my car before and they are anticipation this install).

OCG35

iTrader: (2)

just got the Crawford headers... I hate to say it, but the welds are far less than stellar

Anyone else with Crawford have issue with quality of welds?

Also, where the tubes merge (in the collector) there is significant overlap (one tube ending longer) - I'm hoping this is by design and not from haste.