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#31 |
![]() Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,180
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Original Post:
Some people have asked about port matching the heads to the intake....obvious solution is the taper the IH runner, but if you plan on port matching in the future, you might go ahead and open it up to 36mm from the get go..... if so this is what a 36+MM IH look like when mated to a stock head...to me its not that bad...not optimal; but I am guessing you are still picking up over a tapered runner:
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LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 |
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#32 |
![]() Join Date: May 2011
Location: Sydney, Australia
Posts: 2,466
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Port Match it Lee, You will regret your decision if you don't when the engine is complete.
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#33 |
![]() Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,180
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Come on guys.....
I am not talking about my car...I am talking about when someone sends out an intake to have it ported and does not have the skill to port match their own heads. Do they go 36mm all the way down or port the top part of the IH and then neck it down to 32mm at the bottom of the IH. My 92 is port matched...and thats port match just slightly into the head 391rwhp...no tune my 90 is fully ported into the head...... 441rwhp...thats untuned, small exhaust, stock tb, and I did not play games with dyno....take the air filter off to gain 5 more hp. etc. I regret ever even posting this thread.......
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LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 |
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#34 | |
![]() Join Date: Oct 2013
Location: Wichita Falls,Tx
Posts: 594
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#35 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,683
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Don't think anyone would argue w the original point Lee is making here. Some of us can't STAND the idea of leaving A horsepower on the table. But as an example, Pete and I decided to leave my GVD heads alone on the last upgrade as a compromise. Giving up a bit of flow was worth it for me when considering potential consequence of aggressively porting the head runners. Thought I could make up for it in some other way. Too much hp available just from porting the top end, even without a port match, not to do it IMO. Compromise is in the eye of the beholder. ![]() |
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#36 | |
Join Date: Dec 2012
Location: NC
Posts: 1,783
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It's CLARIFICATION! Even a DEBATE CAN be kept civil. Too few know how tho'... Last edited by Schrade; 03-26-2014 at 02:06 AM. |
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#37 |
![]() Join Date: Jan 2004
Location: Portland, OR
Posts: 1,047
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I prefer to taper to about 34mm even if the heads might be done later. Reason for this is mainly port skew i.e. the intake and head ports rarely line up just right. By leaving a little material to work with on the injector housings I have a better chance at getting a perfect port match when doing the heads.
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Robert ZR-1 Net Registry Oregon State Director 91 ZR-1 #431 Black/Black LPE 368 |
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#38 | |
![]() Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,156
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1) aren't comfortable doing it 2) are on a limited budget to do this 3) are afraid if they screw up the head on the car this porting joib just got real expensive I have not ported, have I thought about it. Absolutely. Am I motivated? not really, I have an extra set of IHs (the originals and if I did them or had them done, I think I would start with porting like Locobob suggested and taper to 34mm on the bottom, then leave the heads alone and see how that works for me. But I am really not in any rush to do that Lee, I think the info is good.. THANKS
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1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Shelby Series 1 - Wilwood Brakes Custom Interior NCM Lifetime Member #978 |
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#39 | ||
Join Date: Dec 2012
Location: NC
Posts: 1,783
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Sorry you choose to not post further on it tho' (I don't see where anyone ELSE was trying to make a 'pissing contest' out of the DISCUSSION), but I hope someone else will try to explain this, without getting upset, what seems to go against logic. Fortunately, NO one knows it all, and EVERYone still can learn a thing or 2, IF THEY WANT: Quote:
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#40 | |
Join Date: Jun 2009
Location: I live at Devens, one run at a time
Posts: 454
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My racing rules limit me to going 1" into the head ports, intake or exhaust. On the other hand if I'm going to crack open the thing (or the wallet), I want to make sure I don't leave anything on the table. After all, this is [strikethrough]war[/strikethrough] racing. To my eye, choices appear to be A) porting IH with <=4deg taper to match the stock head or B) porting to the extent that <=4deg taper can happen within the top inch of the head. Looking at the implements of destruction I honestly didn't think one could taper like "A" in the IH. On the other hand I figured using the 1" into the head would be the way to make sure the ports register properly between the IH and the head. If I think between the lines a little bit it sounds like Lee's answer to my dilemma would be let the head ridge stay, but knowing myself I'd take that to mean stick with tapering in the IH. Maybe the truth lies in the middle, taper the IH from 36 to 33 then use the last mm in that top inch of the head to be sure to align the ports? I am still on the fence about the secondaries. Once in a while I need to leave the car with a mechanic and knowing human nature that's a great time to keep the power key in the pocket so to speak. It sounds like there's nothing to be gained there at the head other than simplification, which I do confess I like a lot... Thanks, - Jeff |
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