Has any here port and polished the heads on the HR? I know Cosworth makes heads but i do know if they make it for the HR plus $4500 is not to cheap. What kind of gains do you guys think we can gain if we port and polish our heads? Also you guys know of any reliable shop where you could send your heads to be port and polished? One of my buddies with an srt8 got his done for around $1500. I got all boltons done and was goin to do a tune but was thinking of the camshaft and heads to get more power. Any idea guys.

 

The cosworth heads are probly for the DE. Porting and polishing will always end up extracting power. How much versus cost is up for discussion. A tune would definetly have to be done with cams and a port/polish. There are many shops on this forum that would probly be willing to help you out. You could also take a look at local shops.

 

I do not mind spending 5-6k with the tune but as long as i hopefully get atleast 30- 40 whp with the heads and cams. my goal would be to get 340 -350 whp with heads and cams and all my boltons tuned.

 

5-6k is expensive. but hey, if you got the money and choose that over FI, than cool.

I hope you achieve your goals. Best of luck.

 

No one can garuntee you anything when you would be one of the first to do it.

 

i ported and polished the head on my specv (qr25), NA we saw 3-4whp, tuned we saw 6peak. After trubo we saw pretty good numbers when compared to same psi specv's without port and polish. Im not saying i was great at it, but we did gain hp before FI on a motor that is known for allowing minute gains from anything but FI. And it was MUCH MUCH cheaper than 5k... i wanna say parts/material cost about 50bucks. Time was all mine and id say i put in a good 8hrs into it.

 

A port and polish by a pro would yield better results. The machines that port and polish cost a few grand alone.

I did my own little hone and polish on the upper and lower plenum pieces. I can't say it did anything, but its cheap, and a good project.

 

Forget it bro... Too Expensive not enough power and more than likely it will yeild very VERY low power gains... You would have to get a cam setup and tune specifically designed for the VQ35HR's with Ported and Polished Heads... Save your hard earned cash... Or if you are really serios about it just go turbo..! and run it on a modest conservative boost...! If your one of those guys who thinks FI is sketchy... Just save up the cash... Pay off the car... and do it right with a BMW 335i Coupe or a BMW 135i... (Buy used with low mileage) and add a Vishnu Chip.... Then see what the Pork is goin on... You would save money on insurance and you would ball WAAAY Harder...!

Just my 2.5 Cents.

 

Hey, theres a NASTY machine shop down here that builds sick engines. They have the most up to date technology for cncing heads, block or anything. They can test airflow and figure out what is the most affective cut on the tubes. The name of the place is, Qarlquist competition engines. 98 Falls ave, oakville, CT 06779. 860-274-0742. Call and get a quote from them.

 

getting a cam to play nicely with that header is going to be your biggest limitation IMHO

the biggest gains on an NA Z are not going to come from porting the heads, it's going to come from the valve work.

this is not something you can just do yourself, it has to be done by an experienced person with the right tools, and instruments to measure before and after. Expect to pay in the $1000-$1200 range for the pair

if you're serious about having it done, let us know