Anyone have cylinder head work done?

**L_RAO** · 09-30-2011, 07:13

I haven't been able to find as much data on cylinder head work, flow rates, power gained on the C30/C32 motor as I thought I would.

There's a ton of information on the B, K, and F series Honda motors.

Anyone have stuff to share?

I'm sure some people have had Portflow or other "head" shops do some work.

I know that GSRguy just had his cylinder heads get the full treatment from Endyn, but even then he didn't get flow bench numbers (though he did make incredible power).

**BATMANs** · 09-30-2011, 08:01

Originally Posted by L_RAO

I haven't been able to find as much data on cylinder head work, flow rates, power gained on the C30/C32 motor as I thought I would.

There's a ton of information on the B, K, and F series Honda motors.

Anyone have stuff to share?

I'm sure some people have had Portflow or other "head" shops do some work.

I know that GSRguy just had his cylinder heads get the full treatment from Endyn, but even then he didn't get flow bench numbers (though he did make incredible power).

I could have sworn that a while ago when I spoke to Cody at lovefab he mentioned something like 330cfm.

Before I had the SOS SC installed I did some research on extrude honing.

I first learned about extrude honing when I had the RX7 and people were talking about doing that to the engine ports, manifolds, etc.

It seems that with regards to the NSX heads, extrude honing on a stock displacement and stock compression ratio block will yield very little benefits if any. That's the jist that I got from STMPO, Driving Ambition, and Lovefab.

I called an extrude honing shop and the verbal quote last year for the NSX heads were $1500.

If you are going to do head work you may want to consider probably the best valves ever made.

I have the undercut valves for the GTO when I did the engine rebuild to handle more power.

Same thing here. Did tons of research and after learning that most of the Supra guys making serious power north of 1000HP I was convinced that these were the valves to get.

The big selling feature and benefit of the Ferrea valves is that they seem to be the only ones made so that if you over rev your engine or if the timing belt were to bust and the valve and piston were to kiss, the valve heads are the least likely to break off and bounce around in the engine causing even more damage. They just simply bend and keep the damage localized to that combustion chamber.

**L_RAO** · 09-30-2011, 08:35

BATMANs,

Thanks for the reply. I've known about Extrude Hone for at least 15 years now back to my 5.0 Mustang days. I personally don't like EH for cylinder head work since I've ported a few domestic cylinder heads myself - there is a lot of re-shaping that can not be programmed into the EH process.

For a while I felt that EH was suited best for intake manifolds where the grinders couldn't reach. But now even that is debatable. If you're looking for serious power good porters will simply open up the manifold, port, then re-weld it back together.

Most porters will tell that the mirror-like/smooth surface that EH leaves is conductive to the air-fuel mixture pooling. They like rough surfaces (how rough I'm not sure) to promote atomization. So maybe a smooth surface UP TO the point of the fuel injector, then rough afterwards?

Anyways, I know that the most power to be gained in any internal combustion engine lies in the cylinder head.

**BATMANs** · 09-30-2011, 08:40

Originally Posted by L_RAO

.....Most porters will tell that the mirror-like/smooth surface that EH leaves is conductive to the air-fuel mixture pooling. They like rough surfaces (how rough I'm not sure) to promote atomization. So maybe a smooth surface UP TO the point of the fuel injector, then rough afterwards?........

Yes, I have heard of this theory too.

Based on the golf ball dimples, shark skin, and other surfaces that seems to help in reducing aero and hydro drag it seems to have merits.

**gsrboy** · 09-30-2011, 08:58

I would contact portflow, endyn, and rlz. Personally if I was to do it over again I would use rlz and toda cams instead of regrind bisi. Many honda guys love them and they have proven their stuff. I hate to admit it but their work is even better than endyn's. I am sure rlz will have a flow test for you before and after.

http://www.rlzengineering.com/index....e=Applications

**BATMANs** · 09-30-2011, 09:03

BTW, I think Driving Ambition does porting too. And since they are a NSX expert and have had numerous track times (plus they are in CA) it might be worth contacting them.....

**TANTO** · 09-30-2011, 09:13

Originally Posted by L_RAO

There's a ton of information on the B, K, and F series Honda motors.

Anyone have stuff to share?

.

Mods on this "high end" engine are f'ing frustrating as the two or three that know anything don't want to share, and i guess i can't really blame them. Since they are not likely to speak up, i'll give my gut feelings. And i'm sure there are some comptech NA engine guys here that will provide better info perhaps negating my comments, and of course i welcome that. The factory heads flow enough for standard displacement engines and possibly even the strokers. Headwork normally simply takes advantage of poor flowing heads which we likely don't have. Generally porting and larger valves simply trade mid range HP for high end HP making the engine peakier. While i like this for the street, it doens't make the car much faster as you are just trading power from one range to the other. It then depends on the gear ratios as to where you want the power. From my experience it's the racers that know what will help and not a flow bench technition. Bottom line, SHAD, SHAD, SHAD is likely the only one who knows about head flow regarding NA, although his input will be all memory as i doubt he's done hardly any NA's in the last decade. But he was around when HONDA was bulding high output NA engines. The spice car put out 440 crank although that engine probably would have too little torque for our full size sleds. I've been out of the community for many years, so if i'm disregarding others out there please accept my apologies in advance. You could help us out! It's so frustrating coming from the iron v8 world were folks will share almost everything all the time. The perception of high end money chasing these high end cars creates opportunitys that screw the DIY guy. And of course if you don't know what your tuners mods are, you can't really tell if you are getting your moneys worth, as well as repairing your ride down the road. It's kept me from major mods for many years. Things ARE much better than they used to be though. I'm on the same track as you. We'll get there.

**L_RAO** · 09-30-2011, 09:27

gsrboy,

Care to elaborate as to why you would go:

(1) RLZ over Endyn
(2) Toda over Bisi

Thanks.

**gsrboy** · 09-30-2011, 18:31

Originally Posted by L_RAO

gsrboy,

Care to elaborate as to why you would go:

(1) RLZ over Endyn
(2) Toda over Bisi

Thanks.

RLZ because their work is top notch but the same goes for Endyn, however they have been more proven on other B, D, K and even supra head. Their work and numbers yield a tad bit more power compare to endyn. They are a bit more expensive but when it comes to NA everything counts.

Toda cams are billet cams and are not regrind. They are much more aggressive than most regrinds including the bisi or SOS cams. Toda cams will give you way more power but you will need extra compression to make these cams work for their money. 13:1 on e85 will make a good amount of power. Even 12:1 should be fine with those cams.

**TANTO** · 10-02-2011, 09:40

In my really long thread i think i failed on the most important point. You have to have a porter that has done heads for an engine with the particular cams you are using and you have real world experience, or dyno on that engine. You need to be a copy cat. If your porter goes just a few hairs too large in his porting, as racers do on purpose, you may have an on-off switch engine that will NO mid range. The heads will then go into the trash. Yes i have been there and done that(non nsx). Street folks almost never port their heads, so head porters are used to doing race engines. You will need to rein them in.

On the big cams, some of these cams may be designed for engines that replace their valve springs every season, or even less. Again you should hear this from the actual users out there, but valve springs are a weakness on the big cam engines. And thats an engine huff. NA is a pita on this expensive engine. I suspect those with experience on this are not chiming because it's all there in past posts. I would search more.

**ken sampson** · 10-05-2011, 05:11

I run stock cams but have had some minor head blending work and larger Ferra exhaust valves put in when I had my Darton pro sleeves installed. I lowered my Comp and installed a 2.9L Whipple and have 525HP at the wheels.

**Honcho** · 10-05-2011, 05:51

Originally Posted by TANTO

Mods on this "high end" engine are f'ing frustrating as the two or three that know anything don't want to share, and i guess i can't really blame them. Since they are not likely to speak up, i'll give my gut feelings. And i'm sure there are some comptech NA engine guys here that will provide better info perhaps negating my comments, and of course i welcome that. The factory heads flow enough for standard displacement engines and possibly even the strokers. Headwork normally simply takes advantage of poor flowing heads which we likely don't have. Generally porting and larger valves simply trade mid range HP for high end HP making the engine peakier. While i like this for the street, it doens't make the car much faster as you are just trading power from one range to the other. It then depends on the gear ratios as to where you want the power. From my experience it's the racers that know what will help and not a flow bench technition. Bottom line, SHAD, SHAD, SHAD is likely the only one who knows about head flow regarding NA, although his input will be all memory as i doubt he's done hardly any NA's in the last decade. But he was around when HONDA was bulding high output NA engines. The spice car put out 440 crank although that engine probably would have too little torque for our full size sleds. I've been out of the community for many years, so if i'm disregarding others out there please accept my apologies in advance. You could help us out! It's so frustrating coming from the iron v8 world were folks will share almost everything all the time. The perception of high end money chasing these high end cars creates opportunitys that screw the DIY guy. And of course if you don't know what your tuners mods are, you can't really tell if you are getting your moneys worth, as well as repairing your ride down the road. It's kept me from major mods for many years. Things ARE much better than they used to be though. I'm on the same track as you. We'll get there.

Great post!

**docjohn** · 10-05-2011, 06:25

I was one of the ones who had the comptech iem package and had the springs fail which toasted that cylinder and thus onto engine #3. I have no idea what my baseline rwhp was but that motor pulled a 298 on a dynojet.I still have those heads with the ct cams.The nsx engine is all head baby.

**Honcho** · 10-05-2011, 13:26

Originally Posted by docjohn

I was one of the ones who had the comptech iem package and had the springs fail which toasted that cylinder and thus onto engine #3. I have no idea what my baseline rwhp was but that motor pulled a 298 on a dynojet.I still have those heads with the ct cams.The nsx engine is all head baby.

Did the retainers cut loose, or did the spring itself fail? Were those Comptech springs?

**BATMANs** · 10-05-2011, 13:32

Originally Posted by ken sampson

I run stock cams but have had some minor head blending work and larger Ferra exhaust valves put in when I had my Darton pro sleeves installed. I lowered my Comp and installed a 2.9L Whipple and have 525HP at the wheels.

What Comp are u running now?

**L_RAO** · 10-05-2011, 13:37

Ouch.

You would think that for the price of the cams/springs/retainers/cam gears, an owner should not have to worry about valvetrain failure...

**docjohn** · 10-05-2011, 14:00

Originally Posted by Honcho

Did the retainers cut loose, or did the spring itself fail? Were those Comptech springs?

I think they were spring cracks.

**TANTO** · 10-05-2011, 18:44

Originally Posted by L_RAO

Ouch.

You would think that for the price of the cams/springs/retainers/cam gears, an owner should not have to worry about valvetrain failure...

I think you'll find it works almost inversely. Cheap parts are made in high production meaning lots of folks have used them and they work. High price often, but not always of course, means few have been made meaning less feedback available. Folks like SOS should have built up quite a knowledge bank by now though as well as Shad and the newer Super Turbo guys.

**TANTO** · 10-05-2011, 18:52

Originally Posted by docjohn

I think they were spring cracks.

So Doc, you've been doing the cam NA thing a long time. What springs and retainers do you recommend? Are the valves you are using lighter than stock. TIA.

**ken sampson** · 10-06-2011, 03:48

Originally Posted by BATMANs

What Comp are u running now?

I think I am around 8:5 to1

**docjohn** · 10-06-2011, 05:31

Originally Posted by TANTO

So Doc, you've been doing the cam NA thing a long time. What springs and retainers do you recommend? Are the valves you are using lighter than stock. TIA.

the springs were scourced by comptech...I did not open the heads and inspect them, and after 2 years they were failing,so if I were to ever do that again I would have to include valvetrain inspection every 18 months or so.

**BATMANs** · 10-06-2011, 07:42

Originally Posted by ken sampson

I think I am around 8:5 to1

Jeeeeezz.

Don't you think that is a bit low? Are you planning on running boost like a Supra TT?

What are your boost/power goals?

For blowers I think a 9.5:1 might be suffice.

**ken sampson** · 10-06-2011, 07:55

I wanted it around 9:1 but after all was done it was to late to go back.
I'm all finished for now and ended up with 525RWHP and some Monster TQ.
Boost is around 17PSI.
Ken