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#21 |
![]() Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,180
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Dominic I remember your port matched heads.....you damn near did a full port job while they were on the car: you went deep!LOL
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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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#22 |
Join Date: Dec 2012
Location: NC
Posts: 1,783
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Alright - I guess it's not cheap to do such extensive testing as I'm asking here...
What IS ... ABOUT the max HP / TQ numbers available for a motor, STOCK, with only airflow mods? |
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#23 | |
![]() Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,466
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As it happens, I snap gauged a primary and secondary runner on those GVD heads, and I wish I had recorded the #s, but what struck me was they were nearly Identical to what I ended up with (while leaving the heads ON); tapered from ≈36.x at the inlet to ≈ 33.x mm (32.5 = my stock#) at the choke point entering the bowl area (read: not much cutting and perhaps only sanding in that spot marked by the valve guide boss.) |
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#24 | |
![]() Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,466
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My WOT rear wheel torque (below) measured stock and after the 508 hp mods were done, which were essentially ALL air flow related fully ported (except for stock TB & air horn), headers, x pipe. And, a big part is the tune and cam timing (see my signature). ![]() Last edited by Paul Workman; 03-25-2014 at 04:51 AM. |
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#25 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,683
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I never got near the bowl area. The 36mm was at the top and tapered from there. I did the surgical masking off thing and had foam stuffed down the runner.
I was using a double fluted burr so as to not cut too deeply w each pass. The primaries were the ones I concentrated on. Just touched the secondaries to eliminate any edge in th transition, otherwise nothing there. I think it was Marc that had recommended a taper that had a 36mm sitting in the opening and a 35mm ball would sit completely into the runner flush w the opening. |
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#26 | |
![]() Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,466
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I removed the throttle plates, but the TB is stock, whereas your TB is ported and you left the throttle plates and rods in place (tied open). So, I'm guessing the two offset each other, and therefore extrapolate to mine from your dyno results measured at that time. Anyway, porting science is very interesting, far as the nuances of what works and and what sometimes doesn't do what was expected. My last Dynojet run showed 432 rwhp. Since then, I modeled some flow number scenarios for upping the TB to 63.x mm and got 6 hp predicted gain, which is more or less confirmed by Marc's empirical experience. In addition, I want to go with the Dynamax 17228s(?)/NPP mufflers (Sharp transitions rub my flow sensibilities the wrong way. The MFs go sharply from 3" inlet down to about 2.5"). I don't know if the combination of the two can get to 450 rwhp on stock cams w/o going to an electric water pump, but it would be sweet! (Would you be interested in playing with my tune as a project, once those two items are accomplished??) Last edited by Paul Workman; 03-25-2014 at 09:40 AM. |
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#27 |
![]() Join Date: Dec 2003
Location: Chicagoland,IL
Posts: 2,667
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Lee, picking up 30-50 HP is nothing new been doing it for almost 15 years.
On the port matching of course it would be nice to match/taper the head to the ported IH's remember we have N/A motors the piston sucks in the air where as a turbo/SC pushes air. Pete
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'91 #1635 PoloGreen 350 LT5 11.09 @ 129.27 11.04 @ 128.86 474RWHP 400RWTQ http://www.youtube.com/watch?v=SFNFOhGGlR4 http://www.youtube.com/watch?v=ZlRIOMwaDYY https://sites.google.com/site/peteszr1garage |
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#28 |
![]() Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,180
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I Agree nothing new, point is.. despite not port matching gains were comparable or better to that of a tapered runner match to the stock port....in other words not port matching to the stock head does not set you back...
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LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 Last edited by LGAFF; 03-25-2014 at 02:47 PM. |
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#29 | |
![]() Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,466
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Just to clarify... You're saying there's no difference in flow between a 36mm IH feeding ≈ 33 mm port matched head vs. one that is not, right? Ya wanna bet a steak dinner on that compadre?? ![]() |
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#30 |
![]() Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,180
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Paul read the post:
This is what I am trying to say: Option 1)Port to 36mm to bottom of IH, no port match, head primary stays at 32mm Option 2)Port top of IH to 36mm and taper to 32mm Option 3)Port to 36mm port match head 36mm primary What I am saying is.....Option 1 is as good or better than Option2 and option 1 is not that substantially different that option 3. Conclusion: Even if you are not port matching, I would still open it up to 36mm.....its as good as the taper and depending on the car as good as some produce with a port match. Plus if you decide to port match later...its ready What I am not saying: *My porting is great or better because a guy got 37 rwhp *Point is someone did not port match yet got results similiar to port matching * That porting a runner 2 inches in would not produce better results; **** if you port the thing down the runner thats alittle more than most people would do port matching. Holy **** this is my last tech post everybody wants to turn this thing into a pissing match
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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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