Port and Polishing heads
 

My shop is going to start pulling the motor Friday . Was wondering what I cant expect to pay to have a bisic port and polish ? Do you guys have any suggestions on where to send them ? No one in this city has done a port&polish on these heads and was told by my shop , I more than likely would be better off sending them out of state to to some one thats done these heads before and have gotten good results . Im thinking on SGP so far [ there doing the block ] and are kinda steep $1500.00 . So Im looking for some help and direction here....Thanks...Bill

Kim Barr Racing here in Dallas ( really Garland) TX quoted me 900, but said it was really a waste of money. Told me I was better off spending that money on cams, spings, and better retainers instead. Most heads these days flow pretty well. P.S. he told me that thre port and polish guy is pretty slow, so you might want to send it in early.

Thanks Spaz...Thats the second time Ive heard that about the heads flowing good already . Im going to do some more thinking on it , depending on the replies I get here . Its a toss up between the heads or a return fuel system

heads
 

SPaz , know of anyone who sells better than stock retainers, Stell maybe ,cheaper than the SGP titanmium variety?

Im adding the Nismo heavy springs with the Nismo cams and I was wonding if you absolutely needed new retainers or would the stocks be ok ?

Unless I was looking for the absolutely nutty max power limits of the VQ, I wont bother with the head work. Its very expensive, and the gains are marginal.

gq-626....Thanks...thats what Im starting think also . My money would be better spent on a fuel return system

Re: heads
 

Well , I am going to run the heavier JWT springs just because I've raised the rev limiter and want to be prety certain , that I won't float a valve. But with the retainers I'm on the fence a bit. I don't really find them necessary, and haven't heard of any failures , but if I can get a set for <$250 it might be worth since my heads are currently appart. But the ~$500 for titanium retainers seem a little over board for this insurance IMO.

Let me know if you find some thing around that price and I'll get them also....Thx Bill

Re: heads
 

yep, SGP are the only one I know of. sorry :(

Who does porting for the 350Z heads? Are there any dyno charts documenting power gains? Anyone do oversized valves??

Chris

We are also offering port and polish for $1500. However, I think this is the last money you should spend on an FI setup because the stock heads flow very well.

I have heard 2 conflicitng theories so far on this..

1) SGP racing feels a Cam would do more for you than headwork..

2) APS as well as Headgames, feel that porting and polish will give you more hp...

Any thoughts on this??

Also I understand Ferra has a complete Valvetrain available for the 350z but its like $1300:eek:

So Lorca,

What would you definitely reccomend doing on the heads for a built motor under FI??
I was thinking just to upgrade the springs to JWT, is this all I would need to do, or do you suggest the entire valve train since I have it apart and port and polish while im in there??
Keep in mind I plan on running stock cams for now then maybee going with JWT or IMPUL when I do the upgraded APS fuel system..My goal is550- 600whp and drivable..:cool:

A properly designed FI cam would probably do more than headwork. I know that JWT, Esprit, Mines, Nismo, Impul & Tomei are offering cams. I *think* the JWT and NISMO cams may be the same product. The problem is I don't know that any of these were designed specifically for FI use.

The stock valve train looks pretty robust and for your goals I think the Ferrea is unnecessary. If you will be upgrading cams in the future the JWT springs are not a bad idea. We are working on a FI cam but I don't want to speculate as to when it will be available :-(

once we are ready to release our head packages I will show you guys the flowbench results of stock head versus our ported heads. there is plenty to improve upon, and you dont have to take my word for it... wait till I show you flowbench at various valve lifts.

as for upgrading springs... if your gonna do springs I would assume your gonna do higher RPM eventually so you might wanna upgrade your retainers. not only is aluminum very soft and tighter springs could possibly wear thru it over time (i have seen this happen to Ti retainers with very agressive springs for a high RPM honda motor, the springs evntually wore thru the seat on the retainer and cracked off 3 of them down the track)... but i am not sure if aluminum is trust worthy in an extreme duty application... your spending so much as is... what the few extra bucks for some SGP retainers.

As for cams... if you want to make really good HP and your inside your engine... cams if your friend. a properly selected camshaft can make lots of power.

Great to hear you guys will have some numbers available soon. Unfortunately, as we have seen on the Z32, flowbench numbers do not always equate significant horsepower gains. Also, FI and non-FI applications have different flow chracteristics so what works well for an NA may not be as effective for FI.

From our conversations with our machinist, as well as a local world renowned race motor specialist, there are not a lot of horsepower gains to be had in the heads of the VQ35DE.

your absolutely correct that flow bench numbers can hardly have any significance... especially if your only flowing the ports. what good is a better flowing exhaust port going to do if its still feeding the same crappy manifold... etc. there is a lot more to it... but flow bench can help see if you have optimized the flow characteristics to acheive good VE at higher RPM.

Im putting in the Nismo cams...which claim better hp in the low to mid range . I though JWT cams made more power up top . So I dont think they are the same cam .
I would like to thank you guys for the info you provide here in the forums. As I am just a dumb a$$ trying to learn as I go.

I remember reading that the JWT cams are designed around NA applications. These FI brain people are smart and im hear to learn too. :icon14: :p

So is there a consensus on what cams are good for stock VQ35DE heads aimming for 500-600 rwhp range?

Im not looking to get that big of hp . But the reason I chose the Nismo cams , is the SC its self .And the fact I lowered compression . And I want to keep as much as possible dow low