I found a set of heads on CL (VQ35DE 350Z G35 Complete Cylinder Heads) and was thinking of picking them up and having them ported and polished.

My car is used for weekend driving and Auto'X (still emissions legal) and was wondering what gians can be expected, if any, if I do this. My car has the usual list of bolt-ons.

Stillen CAI
3/8" plenum spacer
Stillen Y-Pipe
Megan Drift Spec Single Y-back

anybody have any experience? I know getting more power out of a DE without FI is really tough, maybe this would be of some help...

 

porting when done properly can help NA cars quite a bit but if it's just honed out larger it will kill power.

These cars have amazing flow on their stock heads. Cams will help. I think the cost of install and headwork on these cars is not close to worth the gains. I would go back to stock porting if I had the choice.

 

I would have a machinist do the work and i can install heads myself. Given those cost reductions, I would just have them done up to the exact gasket size and smoothed out. Do you think gains would be had then?

 

2-5whp max NA. You have to add cams and long tube headers at the least to realize any gains.

 

Thank you. They're not worth the hassle and my time then. I knew VQ heads breathed efficiently, I was just curious. I appreciate the help. Maybe I'll get them and make a sweet coffee table

 

I would not have a standard machinist do the heads. Go to a specialist with the vq since porting is highly specific for each engine.

I still think it's the worst cost/power upgrade for these cars though.

 

I think I only paid $100 for my head work when I had my engine in the machine shop

 

No offense but I charge 5 times that for the porting I do on just single cylinder dirtbike engines. I wouldn't trust 100$ port work for anything. That's less than 10$ an hour which means someone cut corners.

Heck, I would charge more than 100$ just to port match the intake due to the time involved.

 

I was just reving a VQ35DE that has similar mods to my car, engine-wise. The only difference is that he has his head ported and polisehd. The engine revs much more freely. Not sure how much more HP this mod gives.

 

No meaninful gains unless you have a better intake manifold first, that's the big bottleneck.

 

I don't think it was anything meaningful but I had it done while they had my valve out anyway

 

I would ask for specifics on what they did. Doesn't seem like a shop would be able to even port match for 100$ due to the hours involved. It almost sounds like they just dinged you for an extra 100$.

 

more likely a smoothing out and maybe taking a little bit off... I agree, definitely not a true port match.

 

I have been wondering the same question... I bought a pair of DE heads off G35Driver for $270 Shipped, so I just thought they were worth it to send out for P&P and so I do not have to have my car taken apart while they are P&P'ing them. I am also going to be installing JWT cams, Cam Gears, Valves, Springs, Retainers and PPE LTH's all at once, of course a tune as well, I was hoping to just get a lttile better flow than stock HR heads... I saw a post on here the On Point Dyno did on these heads and it looks very promising..... I believe with those mods listed above I will see pretty nice gains! What do yall think?

 

Send your heads to OnPointDyno then. Not going to find the specificity of application from many other places.

 

Which cams are you getting? Get at least C8's or bigger IMO since it sounds like you are doing a serious NA build.

C9/C10 require head clearancing, and probably machinining the pistons. C8's I have been told are good for around mid 12:1 compression clearance-wise. C9/C10's will require a custom intake manifold or ITB's to take advantage of. C8's will not underperform C2's, and are very streetable. C8's will outperform C2's if you do more work to the intake side of the equation however... so I don't know what the point is in C2's even existing.

As far as porting, since you are getting PPE LTH, you should at least port the heads, I think that will be well worth it, more-so than LTH in the sense that it's easier to install LTH than it is do port work. Also, generic off-the-shelf LTHs might not even be optimal for whatever cams you select, where-as portwork to the heads definitely will be.

You will need to rev higher to take full advantage of cams. Make sure you upgrade to at least a revup oil pump (avoid HR oil pump & cosworth oil pump is overpriced for what it is).

Consider a baffled oil pan since you autoX, and are doing all this work; it's just cheap insurance against oil starvation under lateral G's.

Read, if you haven't already:
https://my350z.com/forum/na-builds/5...w-results.html

I also agree though that the cost is not worth the gains, which is why I ended up deciding against it myself. Have to stop spending at some point.

 

Thanks for info guys. I am doing alot of research on these cams to try to make the best decison possible.... I dont think that Porting the heads alone is worth it, like it is on some V8's and other cars, but when you put the whole package together, it can make for some great power gains......