Port & Polish head - high end gain low end loss?

[RyRy210]

Would port & polishing the head (just port & polish, not talking about the comptech IEM), make more peak horsepower at the expense of low end torque? Does anyone know exactly how much power one can get by just port & polishing the head? Any chance that it will be a gain throughout the RPM range? I know most of you will just tell me to get the Basch Boost or do something else that has more 'value'. I'm not going to do this nor plan to do this, I'm just curious as to what you all have to say in regards to this.

Ryan

 

[Edo]

Gerry Johnson told me that he went from 233rwhp to 266 after his head port and polish.
I think thats well worth the price.

 

[ERicincal]

I got a major service at NSX modified, and while the engine was out Larry did a port and polish on my heads. Feels really strong all throughout the RPM range. I drove another 1995 NSX imediatley after and it didnt seem as zippy. Im stock all around.

like my tech talk?!

 

[BoneZ]

What did it cost to have the heads port/polished?

This may be the "little" extra im looking for to break my goals.

-B

 

[rmani]

wow 33 rwhp was that on a 270hp or a 290? how much is a port and polish?

 

[cojones]

port-and-polish vs extrude-hone ??

I would infer that the effects would be even more pronounced under forced induction

[This message has been edited by cojones (edited 03 April 2002).]

 

[ilya]

Yes, he is referring to just a polish of the intake manifold (all 6 cylinder openings and intake). It runs a bit smoother and adds more zip in combo with some simple mods like intake, exhaust and maybe a timing advance.
I wouldn't expect any large HP gains from it.

I think Gerry's car is a pretty powerful turbo which is why the gains are so pronounced. You're not getting anywhere near 20-30 on a stock motor from just a port and polish of the intake manifold.

I would recommend it though if you already have it out. Doesn't take more than a half hour or so to do. Larry does it for some customer cars like mine if it is already out and don't think he charges much if anything at all. It's a service for good customers.

 

[RyRy210]

Port & Polishing the stock intake manifold will not give you any hp gain, it might on a motor with forced induction. But my question is the porting & polishing the stock cylinder head, not the intake manifold.

 

[Edo]

Ilya, A true Port and Polish takes quite a bit longer and some fairly hard work.
The work Larry did for you was a very very very quick version of a Port and Polish.

I would venture to guess a decent Port and Polish would run near or over 1000 dollars.
Not something someone can do by hand in 30 minutes.

Gerry's said those results were from his car when it was stock.
233 to 266rwhp.

233rwhp is pretty in line for a stock 3.0L.

 

[David]

I believe Gerry used to do head work for Crower, so he probably has a pretty extreme port and polish on his heads. You should shoot him an e-mail and ask him about it. I have found him to be a very nice guy and very informative.

 

[ak]

Originally posted by David:
I believe Gerry used to do head work for Crower, so he probably has a pretty extreme port and polish on his heads. You should shoot him an e-mail and ask him about it. I have found him to be a very nice guy and very informative.

Is there any downside to porting in extreme as you mentioned? I mean, if it is so great without any downside, wouldn't Honda have done it to begin with? Not doubting its effect, but just curious.

 

[David]

Originally posted by ak:
Is there any downside to porting in extreme as you mentioned? I mean, if it is so great without any downside, wouldn't Honda have done it to begin with? Not doubting its effect, but just curious.

By 'extreme' I meant it is probably a very thorough, very careful job with full port matching. There is really not a downside on an aggressive performance motor.

Honda did not do it because it is expensive.

You can get really nice heads for domestics because CNC technology has reached the point where once the machine is programmed, you can whip out, say BBC heads, one after the other, as long as they are all the same. Some aftermarket domestic head companies now have several dozen CNC programs for each type of head or block. We just don't rate that kind of atttention.

 

[nsx4fun]

You might consider port only, hold the polish. The turbulence caused by roughness of non-polish helps keep the atomized fuel from condensing on the walls at low throttle. Polish should be reserved for those that spend most of the time racing under mostly max throttle openings. And it could save you money as less labor is involved.

 

[gheba_nsx]

"Honda did not do it because it is expensive."

Even in a hi-tech, very expensive car like the nsx?
I'd imagine that if you do it before installing the heads it would be quite less expensive and quite automatisable during the production.... am I wrong?

 

[RyRy210]

Eventhough the NSX is a handbuilt car, the individual parts aren't. They are most likely cast within certain tolerances, and the edges of the part will show this. Its like blue printing an engine, rebuilding the engine to match the EXACT specifications intended. Port & Polish is an effort to take away the imperfections from mass producing these individual parts. If each part was given this treatment, I think it will be entirely too expensive for Honda. Aren't the Type R engine blue printed to exact honda specs?

 

[Factor X Motorsports]

Originally posted by Edo:
Ilya, A true Port and Polish takes quite a bit longer and some fairly hard work.
The work Larry did for you was a very very very quick version of a Port and Polish.

I would venture to guess a decent Port and Polish would run near or over 1000 dollars.
Not something someone can do by hand in 30 minutes.

B]

We agree 100% with Edo, a true port and polish takes quite a bit of time. We perform this service on our race engines and on average takes anywhere from 5-8 hours to complete.

Speed Safely,

Factor X Motorsports

 

[rmani]

Originally posted by Factor X Motorsports:
We agree 100% with Edo, a true port and polish takes quite a bit of time. We perform this service on our race engines and on average takes anywhere from 5-8 hours to complete.

Speed Safely,

Factor X Motorsports

do you most of the nsx's you've done see good power gains? 30rwhp that someone else reported is really impressive.

 

[Factor X Motorsports]

Originally posted by rmani:
do you most of the nsx's you've done see good power gains? 30rwhp that someone else reported is really impressive.

IOHO, the 30rwhp is a pretty big number. Doing the port & polish by itself without any other modifications probably wont have that significant of an increase in power. However, if you add any other hard parts that increases airflow (forced induction, headers, exhaust, cams, etc)then the Port and Polish will yield a significant benefit. Think of it as the icing on a cake.

Speed Safely,

Factor X Motorsports


[This message has been edited by Factor X Motorsports (edited 18 April 2002).]

 

[Jason Weaver]

I think some things to take into consideration on the issue of why they heads did not come from Acura that way would be

1.) gas mileage
2.) emissions

Could be wrong, Just my 02.

------------------
Jason

 

[Gerry Johnson]

Originally posted by nsx4fun:
You might consider port only, hold the polish. The turbulence caused by roughness of non-polish helps keep the fuel atomized. This is true, however when you do port work on a street motor and even sometimes on a race motor you do not polish the intake ports or even the intake runners in the manifold you blend the pockets and clean the runners and ports up, also changing the runners in the right places to increase flow, and on the exhaust you change the short side radius, blend the pockets, polish the ports so that the carbon doesn't build up when just cruising around, you then match the intake ports in the manifold with the intake ports in the head so there is no abstuctions to hurt the air flow. When I did this to my NSX and made sure that the cam timing was right I picked up 30 hp on the dyno, some of the power increase did come from the cam timing being corrected. I never ported heads for Crower, but I did port heads for 20 years at a performance shop, Bell & Gaines Racing Engines.

 

[gheba_nsx]

"I would venture to guess a decent Port and Polish would run near or over 1000 dollars.
Not something someone can do by hand in 30 minutes."

RyRy210: Ok, the parts are machine done but if Edo's statement above is true, would 1000$ scare Honda/Honda's flagship customer to pay that (small) amount more to have those 15-30 additional, NA, OEM, horsepowers?

 

[nsx4fun]

My experience with Honda designs over the years is they are conservative. Consequently, you get a very reliable machine. And if you want to modify it to get more out of it, you can, and still have a reliable engine. Engines that are designed and built to get every last ounce of horsepower out are used in racing where it only has to last 500 miles, or for some engines 1/4 mile. It's pointless to complain, why didn't they do this for only another $1000, they know they could do lots of things, but what we get to buy is the result of lots of compromises. Be glad they made such an awesome machine, and feel free to improve upon it as you desire.

Fritz

 

[RyRy210]

As you all know, peak gain really doesn't say as much as a broad well rounded power curve. I started this thread with the question whether I will get high end gain, but losing some low end power if one does the port & polish. That still remains to be answered. My guess is that I will lose some low end in exchange for high end power. If this is true, then maybe honda engineers thought that more street driving is done than race driving and more low end power is desirable.

I gave some consulting advice to H&R Block in creating a better billing system for all their branches across the US. I was appalled at how inefficient it was. They would jot down a person's personal info & credit card info on paper, and process the credit card weeks, if not months later. Most consumers they had expected them to run the card thru right away. Consumers would get notices upon notices of threats to pay them right away because by the time H&R block got time to process their card number, their old card was either lost, cancelled, or had reached its credit limit.

Now you might ask, how is it relevant to this discussion? Envelopes and stamps are not inexpensive, but when you are talking about mass quantities, its a huge number. H&R Block could have saved lots of money if they had a just in time billing system, which they have now. This saved all those unnecessary mailing costs, and made client relations better. When talking about spending an extra $1,000 to get it port & polish, we also expect them to do it to every car. The cost will not seem small if you look at it in terms of the entire # of NSXs produced. We are talking about millions of dollars here. Will honda pass these costs on to the consumer? I have no idea, but I bet you there are many other factors at work.

On a different note, why didn't honda use a better exhaust system & use stainless steel? better Headers? We know alot of things can be done to get more power, why didn't honda unleash its full potential? Its a compromise between cost, power, reliability, and liveability. Some people like their NSX quiet, some want to make it scream like a Ferrari. Honda had to make a happy medium.

[This message has been edited by RyRy210 (edited 06 April 2002).]

 

[Sensei]

Originally posted by Gerry Johnson:

Originally posted by nsx4fun:
You might consider port only, hold the polish. The turbulence caused by roughness of non-polish helps keep the fuel atomized. This is true, however when you do port work on a street motor and even sometimes on a race motor you do not polish the intake ports or even the intake runners in the manifold you blend the pockets and clean the runners and ports up, also changing the runners in the right places to increase flow, and on the exhaust you change the short side radius, blend the pockets, polish the ports so that the carbon doesn't build up when just cruising around, you then match the intake ports in the manifold with the intake ports in the head so there is no abstuctions to hurt the air flow. When I did this to my NSX and made sure that the cam timing was right I picked up 30 hp on the dyno, some of the power increase did come from the cam timing being corrected. I never ported heads for Crower, but I did port heads for 20 years at a performance shop, Bell & Gaines Racing Engines.

Wow! 30hp, that's incredible! Although I am a little confused?
"some of the power increase did come from the cam timing being corrected." How is it that the cam timing was incorrect to begin with? This should never change and cannot change unless your timing belt was replaced incorrectly. Did you use adjustable cam gears? If so, which cams were adjusted, intake or exhaust?

Just some FYI for those interested...
With today's technology, costs and time have been cut down dramatically using what is called "Extrude Hone" http://www.extrudehone.com/

-Sensei

 

[Sensei]

Originally posted by Sensei:

Originally posted by Gerry Johnson:

Originally posted by nsx4fun:
You might consider port only, hold the polish. The turbulence caused by roughness of non-polish helps keep the fuel atomized. This is true, however when you do port work on a street motor and even sometimes on a race motor you do not polish the intake ports or even the intake runners in the manifold you blend the pockets and clean the runners and ports up, also changing the runners in the right places to increase flow, and on the exhaust you change the short side radius, blend the pockets, polish the ports so that the carbon doesn't build up when just cruising around, you then match the intake ports in the manifold with the intake ports in the head so there is no abstuctions to hurt the air flow. When I did this to my NSX and made sure that the cam timing was right I picked up 30 hp on the dyno, some of the power increase did come from the cam timing being corrected. I never ported heads for Crower, but I did port heads for 20 years at a performance shop, Bell & Gaines Racing Engines.

Wow! 30hp, that's incredible! Although I am a little confused?
"some of the power increase did come from the cam timing being corrected." How is it that the cam timing was incorrect to begin with? This should never change and cannot change unless your timing belt was replaced incorrectly. Did you use adjustable cam gears? If so, which cams were adjusted, intake or exhaust?

Just some FYI for those interested...
With today's technology, costs and time have been cut down dramatically using what is called "Extrude Hone" http://www.extrudehone.com/

-Sensei