porting my 1g head needed?

[giovanniv]

Alright well I am trying to push my stock rebuilt 1g 7 bolt close to the limits and aiming for 425-450hp and I am wanting to possibly get some head work done. I have been reading a ton of different threads stating on how it kills smaller turbo's top-end and how porting doesn't neccessarily mean more power etc etc but my question is, what exactly benifits me the most then? Like is it a 3 angle valve job or getting 1mm oversized valves etc. Here is my some of my mods off the top of my head.

dsmlink
hx35
delta 272 cams
wally 255
aeromotive afpr
3in exhaust
pte 880's


I also need some help in what springs and retainers to go with my delta 272's. I have seen a good amount of people running dual valve springs and titanium retainers. I take it that is a fairly good combo?

 

[92tsiawdguy]

At 450hp you dont need porting. the stock head will flow fine up to 600 hp. Run beehive springs they are around 450 but if you ever upgrade later you will save money. You also dont need 1mm over sized valves. They wont help anything.

 

[giovanniv]

Alright so any portwork I do to the head won't drastically really help me with getting faster spool up time?

 

[e85_4g63]

I believe the right porting will help with every combination. When you say you want to (or want to get) your head ported, what did you have in mind? Or are you asking for advice in general? I don't feel that you NEED "stage (insert your favorite number here) head porting" at your intended power level. However, gasket matching, smoothing the factory casting imperfections, and some polishing would be and money well spent.

what exactly benifits me the most then? Like is it a 3 angle valve job or getting 1mm oversized valves etc.

I also need some help in what springs and retainers to go with my delta 272's. I have seen a good amount of people running dual valve springs and titanium retainers. I take it that is a fairly good combo?

Stock valves with a 3 angle CORRECT valve job will be just fine.

A good (Manley, Kiggly, or FP) single spring and retainer setup will be fine. Stock springs and retainers (if your limited on money, who isn't) are ok to around 7,500 to 8K rpm, speaking from personal experience).

Alright so any portwork I do to the head won't drastically really help me with getting faster spool up time?

*drastically* NO. You can "slightly" help spool up with your tune though. (by slightly we're talking less the 100 rpm's.

 

[giovanniv]

Well I guess I am asking in general since I still do not know much about what what can be done to a head and why I would want it done. I mean I don't really want to spend 400+ bucks on port work if it isn't going to be very noticable.

 

[e85_4g63]

I don't want to give you any wrong information or idea's so I'll keep my reply simple. I think gasket matching, a good 3 angle valve job, smoothing out the factory casting flaws, blending the bowls, and polishing are going to be about the most that you'll need. There are people out there pushing 400whp without touching the motor (save for an MLS head gasket, ARP's and cams), so "in theory" a ported head for 425 or even 450 is not needed. I say in theory because I don't have dyno sheets to back up MY claim that 450hp is possible without porting.

 

[gsxitement]

I believe the right porting will help with every combination. When you say you want to (or want to get) your head ported, what did you have in mind? Or are you asking for advice in general? I don't feel that you NEED "stage (insert your favorite number here) head porting" at your intended power level. However, gasket matching, smoothing the factory casting imperfections, and some polishing would be and money well spent.



Stock valves with a 3 angle CORRECT valve job will be just fine.

A good (Manley, Kiggly, or FP) single spring and retainer setup will be fine. Stock springs and retainers (if your limited on money, who isn't) are ok to around 7,500 to 8K rpm, speaking from personal experience).



*drastically* NO. You can "slightly" help spool up with your tune though. (by slightly we're talking less the 100 rpm's.

agreed.

 

[wird06DSM]

I believe the right porting will help with every combination. When you say you want to (or want to get) your head ported, what did you have in mind? Or are you asking for advice in general? I don't feel that you NEED "stage (insert your favorite number here) head porting" at your intended power level. However, gasket matching, smoothing the factory casting imperfections, and some polishing would be and money well spent.

I can back this up this is all i did to my 6 bolt head and also flow benched it. There was good gains.

Intake
.100 .200 .300 . 400 .500
85.7 164.7 221.3 274.1 285.0

Exhaust
.100 .200 .300 .400
44.0 156.3 206.5 228.3

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[diambo4life]

No, it's not needed.

 

[JacksonAuto]

Flow bench numbers aren't always the end all be all. More flow does not equate to a proportionate increase in HP. The numbers are also worthless unless you've got a reliable, accurate baseline test to compare to. By this I mean numbers derived from the same bench, same test equipment (orifice plate, entry radii, exh. pipe, etc.), and same test procedures. It also helps if the data is corrected for weather.

However, like previously stated, the proper port work will appreciably increase the performance of your engine. Will you benefit from an all-out, fully ported and "worked" head? That would probably be a waste. If you were to have the head port-matched, blend the bowls, clean up the chambers and add a good set of springs, valves and a good valve job you would notice good gains in the power band, throttle response and better spool.

 

[wird06DSM]

i do have the numbers somewhere. I just have to find my paper work, all my stuff was done on the same flow bench. I mainly did mine just to see what would happened and to see if it was either worth it or not.

 

[BogusSVO]

I will say Jackson Auto Machine (JAM) got it spot on.

I have flowed heads that have been "back yard " ported, and flowed WORSE than a stock untouched casting.

A well designed runner /bowl will have the proper cross section with a good velocity with it.

Bigger is not always better.

If you just polish the floor of the runners, and leave the short turn radus alone, then gasket match and blrnd in the first inch of the runner, and remove the cast flashing and parting lines. you will be fine.

I like to use the +1mm as a repair valve, if a head has had a valvejob or two done before, to bring the the valve head back up into the combustion chamber, and to bring the spring installed height back to factory spec,

The #1 reason, some people do not see good gains from a +1mm valve, is that they were not installed properly. The shop will cut the seat to take the +1mm valve head, but not open the throat of the bowl.

when the throat of the bowl is not open up, it becomes the restriction, and will still only flow like a stock valve.

 

[TSIfreek]

IMO I would rather run a stock port head than a modified one no matter what the HP. Its all in the quality of the valves you use the valve job/ bowl blending and high quality valve springs are what make these heads work.. Cant forget cams as well to match the application.

 

[diambo4life]

IMO I would rather run a stock port head than a modified one no matter what the HP. Its all in the quality of the valves you use the valve job/ bowl blending and high quality valve springs are what make these heads work.. Cant forget cams as well to match the application.

Absolutely. Some of this "port work" can actually make the head flow and perform worse than it does untouched.