Port Polish SR with pics

[mjjstang]

I was bored today so I got the dremel(s) (blew the motor out on the first one) out and began porting and polishing my spare sr head. I will be getting some work done to it and thought that I might as well try to massage some extra ponies if possible. I know there are a lot of articles out there about this, so mainly I wanted to post so you guys could take a look and tell me whether I wasted my time or if it actually looks halfway decent.

My setup is:
Stock bottom end s13 SR
Gt2871r .64
ARC FMIC
Stock Ceramic coated Exhaust manifold
Stock intake manifold
Enthalpy tuned ecu for:
550cc
Z32 maf
I will be running around 17lbs after I install this head with:
Apexi metal head gasket
ARP studs
740cc injectors
BC 264 cams
BC springs and retainers

oh and duh full 3" nurspec exhaust.

I am having the shop resurface the head, Hone the cam bearings, (some scoring is evident), Hot tank, 3 angle valve job, assemble the head with cams, etc. (for liability they will have to do the assembly. This is the first time I have let someone else touch my engine/car). They said 370, but I forgot to tell them that there is an amount of reshimming that will need done before cams. What do you guys think about 370 is that too much.

Told me that it would be around 500 to do that and my JWT guides, they said they will check them and if needed then I will have them install the guides, It is just a lot of labor.

Couple questions about the port/polish job.

I am only planning on the exhaust side and leaving the intake as it is, From reading other threads the exhaust is the most critical, any disagreement about not doing the intake?

The gasket has a little slop when put over the studs, this allows in certain positions, the gasket to come up over the lip of the exhaust runners, thus when installed, it is possible that the gasket would be interfering and sticking up into the runners. Notice the pic with the gasket, there is a small lip before the "o-ring" type impression on the gasket, can I dremel down this lip, while leaving the "o-ring" lip in tact?
I would think that all the porting/polishing would be for nothing if this lip from the gasket was impeding flow. (I know some may say I over bored it, but it looks perfect when the gasket is centered, only when it is pushed up or down is there a problem, and I think that this little lip around the gasket is not a problem, just wanted to check with you guys.

Also If I were to match the exhaust manifold, which has been ceramic coated inside and out, am I risking a problem because of the ceramic coating, would this weaken the integrity of the coating which could cause flakes, etc to enter the turbo later on down the line? again, if I don't match it, The air rushing is going to slam right into the ridge and probably make the job worse than if I hadn't touched it at all.

Anybody want to guess at what kind of gains will be had on this system, I hate asking but what the hell.


I am not trying to master the art but this is what an hour got me so far.
I've done 2 runners but these pics mostly show one done and one not.
Openings went from roughly 1.65"x1.15" to 1.75"x1.2"

http://i5.photobucket.com/albums/y186/mjjstang/port1.jpg

http://i5.photobucket.com/albums/y186/mjjstang/port2.jpg

http://i5.photobucket.com/albums/y186/mjjstang/port3.jpg

http://i5.photobucket.com/albums/y186/mjjstang/port4.jpg

http://i5.photobucket.com/albums/y186/mjjstang/port5.jpg

[s14unimog]

oh my god throw it away you fail!


just kidding, it looks like you did a pretty decent job port matching but the stock shown is too dirty to tell much. Does that shop have a flow bench? Maybe you could just check the one you've done.

Either way I would be interested to know how you hurt it, IF you did.

Rep for balls!

[phi_ho1]

look great bro

[SR2Zero]

Yeah, like the other guy said... the stock side is too dirty... I'd like to see if there is any results for this.

+1

[mjjstang]

The stock side is very dirty, yes, but you can see the enlargement side-by-side, that is mostly what I was showing, now there is definitely casting marks throughout the runners before the polishing was done. Even if this just helps by gasket matching, then I think it was worth it. Cost nothing.

can anybody answer my question about matching the manifold which is ceramic coated, can I just file that down or will it need to be re coated afterward?

[Forge]

On the ceramic coating the main thing is the outside to keep the heat inside the manifold so you can port match without worrying about getting it recoated

[mjjstang]

On the ceramic coating the main thing is the outside to keep the heat inside the manifold so you can port match without worrying about getting it recoated

Thanks I was just worried that by starting to strip the coating, It would weaken the bonding etc, and create a flaking issue, metaphorically speaking the way a piece of rope frays to hell when it has been cut. get my drift. Thanks for the response.

[iwishiwas-all*]

you are not gonna like what i am about to say but here goes...

odds are you just deminished flow considerably... I have been working in my schools ic engines lab, have done many flow bench trials with varying heads and infact have a s13 sr20 head about to do a blow down bench (aka exhaust port flow bench) but the project is stagnent until prob next week... anyways I will be the first to tell you that how you ported it is not very good, since you wont know if you took too much off of one cylinder etc... or not enough, the best way to do experimental stuff like this is by hand, after baselining on a flow bench and checking gains then matching your numbers to each cylinder on the flow bench by duplicating the port (or tying to but you check this by using a flow bench).
if you didnt take too much off of the short side radius and depending on your grinder job you could have created edy currents and breakup at higher lift...

its a hard deal to do. now the reason i have yet to grace everyone (non premie) with my project sr flow bench is cause my prof. is super busy with some contract work and he sort of runs the flow bench deal lol.

take this on for size: in the lab right now we have a ford Nascar Sprint Cup cylinder head on a prototype flow bench (im not gonna give specifics but its wayy different) and the head has been flowed on the conventional flow bench as well, machine ported (all computerized, extremely clean) and the ported exhaust port flows <5% better than stock but on the prototype flow bench (which is much better at simulating the pressures of an actuall motor in opperation) it flows almost 20% worse than the stock....

food for thought... its definately a hard thing to do properly

[mjjstang]

hmm, interesting, in all of my reading, I read that gasket matching, and smoothing out the port on exhaust side could only help if anything at all because a smoother flow will spool the turbo quicker, i am going to port the exh manifold more than the head so there is no ridge at all where they meet up but that is interesting info and I wish I could have tested a before and after, however I could not believe that my porting and polishing could give a negative 20% flow. I guess seat of the pants dyno will have to work for this one.

[steve shadows]

you are not gonna like what i am about to say but here goes...

odds are you just deminished flow considerably... I have been working in my schools ic engines lab, have done many flow bench trials with varying heads and infact have a s13 sr20 head about to do a blow down bench (aka exhaust port flow bench) but the project is stagnent until prob next week... anyways I will be the first to tell you that how you ported it is not very good, since you wont know if you took too much off of one cylinder etc... or not enough, the best way to do experimental stuff like this is by hand, after baselining on a flow bench and checking gains then matching your numbers to each cylinder on the flow bench by duplicating the port (or tying to but you check this by using a flow bench).
if you didnt take too much off of the short side radius and depending on your grinder job you could have created edy currents and breakup at higher lift...

its a hard deal to do. now the reason i have yet to grace everyone (non premie) with my project sr flow bench is cause my prof. is super busy with some contract work and he sort of runs the flow bench deal lol.

take this on for size: in the lab right now we have a ford Nascar Sprint Cup cylinder head on a prototype flow bench (im not gonna give specifics but its wayy different) and the head has been flowed on the conventional flow bench as well, machine ported (all computerized, extremely clean) and the ported exhaust port flows <5% better than stock but on the prototype flow bench (which is much better at simulating the pressures of an actuall motor in opperation) it flows almost 20% worse than the stock....

food for thought... its definately a hard thing to do properly

No your completely right. I usually argue against porting or polishing of any kind unless your taking it to an experienced engineer, preferably with test experience on that exact or similar head design.

Rick Kemph is the guy I most suggest

[TheWolf]

y
if you didnt take too much off of the short side radius and depending on your grinder job you could have created edy currents and breakup at higher lift...

its a hard deal to do. now the reason i have yet to grace everyone (non premie) with my project sr flow bench is cause my prof. is super busy with some contract work and he sort of runs the flow bench deal lol.


Care to post a stock SR head flow chart with short side velocities?

People can port all they want but if they don't keep the velocity up then it's a waste. Porsche has been experimenting with creating a choke point further up in the intake manifold that in the port area to cause the air to expand and cool right before entering the port for turbo vehicles.

I would be curious how your head development continues. Few post actual numbers.

[mjjstang]

hmm, as I am curious, I think I am going to take it to the dyno before and after. Obviously it wont be fair because of the cams, but still it will show if the gain was healthy or not. Far from a flow chart, but it will show something.