How much HP will I get by porting intake? [Forums - C4 Technical]

C4 Technical > How much HP will I get by porting intake?
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WW7	How much HP will I get by porting intake?	#1
Senior Guru Almost Heaven WV 268 Posts Member since: 2007/9/7 0:00	Hi all, I have heard the best bang for your buck on a 89 stock L98 is to do the intake and exhaust.How much hp gain will I get if I have the plenum ported, buy larger runners, and either port the intake or get a aftermarket intake.Right now I have a High flow cat and muffler elimintors on the car,will this allow it to breath enough or do I have to do headers also.. Thanks in advance...WW
	Posted on: 2008/11/19 17:59

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cuisinartvette	Re: How much HP will I get by porting intake?	#2
Elite Guru 1782 Posts Member since: 2005/9/16 0:00	Dont know the exact# depends on what you use. I think Joe (anesthes)may know, sounds like he has done it all modding TPIs On a build thats going together now: Overported stock bas AS&M runners with some further work Stock plenum siamesed, ported IMO Siamesing the plenum is a complete waste. Once the wall (3/4" thick) is gone you have the flat surface of the runner flange so IMO it does nothing. I took the wall down between the runners about an inch or so high and shaped/tapered it down such as an air foil (lol) might be. You can also blend the lip of the runner where it meets the flange, work carefully there. Real gains who knows but it makes sense to do it . I have read about the plenum porter guy doing these and wondered about it so after doing one yesterday and fitting the runners up it was clear without doing that also the plenum was a waste of time by itself.Spend time on the entry way behind the TB. Should only take a few hours tops to do everything, not much else to do inside a TPI plenum. Some call all of it a waste of time but being as TPIs arent the best to begin with everything helps. Some may disagree which is cool.
	Posted on: 2008/11/19 18:08
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Aardwolf	Re: How much HP will I get by porting intake?	#3
Senior Guru Fremont, WI 209 Posts Member since: 2008/4/30 15:21	If you make the base as large as my big mouth base then I would suspect you'd run similar times. I ran a best of 13.22 at 102. With headers etc.
	Posted on: 2008/11/19 19:12

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cuisinartvette	Re: How much HP will I get by porting intake?	#4
Elite Guru 1782 Posts Member since: 2005/9/16 0:00	Im not sure on the size of the big mouth, are they 1.7 or something like that? Im sure with further porting they kick ass.
	Posted on: 2008/11/19 19:42
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Aardwolf	Re: How much HP will I get by porting intake?	#5
Senior Guru Fremont, WI 209 Posts Member since: 2008/4/30 15:21	I didn't open mine up much, mostly cleaned up all the casting mess. This is what I have for measurements: Stock GM Base, runner length 6.375" port in 1.47" port out 1.96x1.20" TPIS base, runner length 6.125", port in 1.75" port out 2.09x1.28" Should be pretty close to your 1 3/4". I wonder why the base intake runner length is different.
	Posted on: 2008/11/19 19:50

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dan0617	Re: How much HP will I get by porting intake?	#6
Senior Guru Tyrone, PA 1260 Posts Member since: 2007/12/30 0:00	I think the general consensus is that you will get about 600 horsepower. Seriously though, porting, 1.6 rockers and LT headers with dual exhaust will give you a nice bump in performance and let you rev just a little higher to pick up a few more ponies. Buy a used set of rockers and a used catback from an LT1 car to save some money if you prefer.
	Posted on: 2008/11/19 20:14
	_________________ ´89 Vert, 383, 230/236 cam, AFR 195's, LT Headers, HSR intake, 2800 stall, Zex 200 shot, ET Street Radials, tune by me. Runs were with D36 3.07's. On spray, 10.55 @ 132.78, 1.55 60 ft. On motor, 12.08 @ 113.15, 1.66 60 ft.
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Aardwolf	Re: How much HP will I get by porting intake?	#7
Senior Guru Fremont, WI 209 Posts Member since: 2008/4/30 15:21	This site http://members.cox.net/effergyvette/8 ... stall/intake_install.html showed a gain 16.5HP and 17.9LB/FT of torque from just the intake.
	Posted on: 2008/11/19 20:29

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85L98-84L83	Re: How much HP will I get by porting intake?	#8
Guru Newb 113 Posts Member since: 2008/1/7 0:00	stock 14.66 pulleys 14.50 air foil, plug wires,K&N, hypertech chip, 160 stat, 14.18 super profile camshaft 13.47 ZZ9 camshaft 13.39 y pipe & muffler eliminators 13.12 big mouth intake, large tube runners, poted plenum, 52mm Throttle body 12.93 AFR heads 12.53 headers 12.32 In my opinionthe intake and runners help on the top end and take away from the bottem end, I guess it tits for tat. The camshaft and the heads is what makes the car perform these 2 items alone = 1.2 seconds off your 1/4 mile.
	Posted on: 2008/11/19 23:47
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bogus	Re: How much HP will I get by porting intake?	#9
Grand Imperial Pooh-Bah San Pedro, CA 20859 Posts Member since: 2005/9/7 0:00	I would be curious what numbers you would get if you added a dual exhaust w/bullet cats and lost that center cat.
	Posted on: 2008/11/20 2:56
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Schrade	Re: How much HP will I get by porting intake?	#10
Elite Guru eastern NC / e-i-e-i-o 1909 Posts Member since: 2008/8/15 2:01	Quote: dan0617 wrote: I think the general consensus is that you will get about 600 horsepower. Beattopunch... 350 intake flow dynamics are for a 305 TPI.
	Posted on: 2008/11/20 13:07
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BeachBum	Re: How much HP will I get by porting intake?	#11
Master Guru 751 Posts Member since: 2008/11/20 17:01	In my opinion, the best modification for a C4 if your just looking to spend a little, but see a real performance gain is a torque converter. With your stock C4 TPI set-up, a little 12" 2500 rpm converter would work great.... they can be had for $ 300 or less depending on where you get it. If you're content on doing an engine modifications one at a time, I always advise to start from the middle and work your way out. Thus, if you're staying with your original shortblock, then slap in an aftermarket hyd roller cam..... I recommend the LPE 211 for your application..... its designed to compliment your long tube runner tpi set-up. You'll need new springs too. In the future, as you can afford it, you can upgrade the cylinder heads, intake, exhaust etc.... and not have to take them off again. It would be ideal if while you have your aluminum cylinder heads off the car you could have a some light port work with a valve job..... (perhaps around $ 700-800).... with the cam and light port work, you could see a real 50+ HP gain even with the stock exhaust. good luck !
	Posted on: 2008/11/20 17:29
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Schrade	Re: How much HP will I get by porting intake?	#12
Elite Guru eastern NC / e-i-e-i-o 1909 Posts Member since: 2008/8/15 2:01	Just noticed you got a wing. That's good for about ... oh ... I'd say 600 HP (about).
	Posted on: 2008/11/20 17:54
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dan0617	Re: How much HP will I get by porting intake?	#13
Senior Guru Tyrone, PA 1260 Posts Member since: 2007/12/30 0:00	Quote: Blade_1 wrote: Just noticed you got a wing. That's good for about ... oh ... I'd say 600 HP (about). Don't believe anything Blade1 says. I installed that same wing and only got 598 horsepower. That about 600 number is a bunch of
	Posted on: 2008/11/20 19:22
	_________________ ´89 Vert, 383, 230/236 cam, AFR 195's, LT Headers, HSR intake, 2800 stall, Zex 200 shot, ET Street Radials, tune by me. Runs were with D36 3.07's. On spray, 10.55 @ 132.78, 1.55 60 ft. On motor, 12.08 @ 113.15, 1.66 60 ft.
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dan0617	Re: How much HP will I get by porting intake?	#14
Senior Guru Tyrone, PA 1260 Posts Member since: 2007/12/30 0:00	Quote: BeachBum wrote: In my opinion, the best modification for a C4 if your just looking to spend a little, but see a real performance gain is a torque converter. With your stock C4 TPI set-up, a little 12" 2500 rpm converter would work great.... they can be had for $ 300 or less depending on where you get it. If you're content on doing an engine modifications one at a time, I always advise to start from the middle and work your way out. Thus, if you're staying with your original shortblock, then slap in an aftermarket hyd roller cam..... I recommend the LPE 211 for your application..... its designed to compliment your long tube runner tpi set-up. You'll need new springs too. In the future, as you can afford it, you can upgrade the cylinder heads, intake, exhaust etc.... and not have to take them off again. It would be ideal if while you have your aluminum cylinder heads off the car you could have a some light port work with a valve job..... (perhaps around $ 700-800).... with the cam and light port work, you could see a real 50+ HP gain even with the stock exhaust. good luck ! I couldn't agree more that a higher stall converter would benefit you alot. Just be careful in choosing the stall speed with a TPI setup. 2500 the absolute max I'd go. I installed a 2800 stall last fall, knowing I was going to a HSR intake over the winter. For the fall months the car wasn't good. It would launch like a beast but for the rest of the run the rpms stayed higher than the TPI's peak. I slowed down alot because of running higher than the powerband. I'd go with about a 2200 stall if I were you. A properly chosen stall converter helps with a less than optimal gear ratio as well. I'm a big advocate of used parts, and you can pick up a good higher than stall converter used for pretty cheap. Check with jsup if you are interested, he had one for sale a week or 2 ago. As far as heads, there is power to be had in reworking the 113's if staying with a TPI intake. If scrapping the TPI setup then go with good aftermarket heads. I'll be selling a set of totally reworked 113's with 2.02/1.60 valves right after Christmas because they just arent enough for me.
	Posted on: 2008/11/20 19:29
	_________________ ´89 Vert, 383, 230/236 cam, AFR 195's, LT Headers, HSR intake, 2800 stall, Zex 200 shot, ET Street Radials, tune by me. Runs were with D36 3.07's. On spray, 10.55 @ 132.78, 1.55 60 ft. On motor, 12.08 @ 113.15, 1.66 60 ft.
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BeachBum	Re: How much HP will I get by porting intake?	#15
Master Guru 751 Posts Member since: 2008/11/20 17:01	Quote: dan0617 wrote: Quote: BeachBum wrote: In my opinion, the best modification for a C4 if your just looking to spend a little, but see a real performance gain is a torque converter. With your stock C4 TPI set-up, a little 12" 2500 rpm converter would work great.... they can be had for $ 300 or less depending on where you get it. If you're content on doing an engine modifications one at a time, I always advise to start from the middle and work your way out. Thus, if you're staying with your original shortblock, then slap in an aftermarket hyd roller cam..... I recommend the LPE 211 for your application..... its designed to compliment your long tube runner tpi set-up. You'll need new springs too. In the future, as you can afford it, you can upgrade the cylinder heads, intake, exhaust etc.... and not have to take them off again. It would be ideal if while you have your aluminum cylinder heads off the car you could have a some light port work with a valve job..... (perhaps around $ 700-800).... with the cam and light port work, you could see a real 50+ HP gain even with the stock exhaust. good luck ! I couldn't agree more that a higher stall converter would benefit you alot. Just be careful in choosing the stall speed with a TPI setup. 2500 the absolute max I'd go. I installed a 2800 stall last fall, knowing I was going to a HSR intake over the winter. For the fall months the car wasn't good. It would launch like a beast but for the rest of the run the rpms stayed higher than the TPI's peak. I slowed down alot because of running higher than the powerband. I'd go with about a 2200 stall if I were you. A properly chosen stall converter helps with a less than optimal gear ratio as well. I'm a big advocate of used parts, and you can pick up a good higher than stall converter used for pretty cheap. Check with jsup if you are interested, he had one for sale a week or 2 ago. As far as heads, there is power to be had in reworking the 113's if staying with a TPI intake. If scrapping the TPI setup then go with good aftermarket heads. I'll be selling a set of totally reworked 113's with 2.02/1.60 valves right after Christmas because they just arent enough for me. I actually had a different experience..... albeit, mine was with a 383/219/AFR 190 set-up utilizing a PI Vig 3000 rpm converter, I put on the stock TPI, and was extremely impressed with everything..... car was docile, no slippage whatsoever and when you gave it gas, as expected it shot hard. Ran 12.0 with a 1.52 60ft..... would have easily been an 11 second et, but the transmission was set-up for shifting at 6000 rpm that day, which was wayyyy to high. Conventional thought by most is to run a 2200-2600 rpm converter for a long tube runnered TPI..... and its not bad advise, but, I also do not think as much as 3200 is too high..... lands you right in front of tha torque peak and you go.... or at least you go until 4500 rpm or so But, not sure what converter you were running, but maybe it was our difference in converters ? Don't know.
	Posted on: 2008/11/20 21:38

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dan0617	Re: How much HP will I get by porting intake?	#16
Senior Guru Tyrone, PA 1260 Posts Member since: 2007/12/30 0:00	Definitely a difference in something! I'm running a 2800 stall TCS converter. My rings are shot so my power is down a little but.... When I hold the brake as hard as I can and give it gas slowly, it comes up to about 2600 or a hair more and starts pushing the car forward. I launch from about 2000 rpms to give me a little run at the stall. I'd launch from just off idle and get more of a run at the converter but I don't think my D36 would like that. Anyway, I datalogged my runs. Not spraying nitrous (I'm about 325 hp at the wheels), after shifts the rpms only drop down to about 4400, give or take a little. If I do the same thing and spray a 175 shot (I'm about 475 hp at the wheels), after shifts the rpms never drop below 5000. I originally thought the rpms would drop down to whatever the advertised stall speed is of the converter. Not true. I like my TCS but it is not a vigilante. It is a little "loose" which could be why mine acts differently than yours. I think the stall speed is right when standing on the brake and giving a little gas but I have a feeling that the looser the converter the more it acts like a higher stall converter with an increase in hp/tq. I have a feeling that with my 383, bigger cam than before and a 200 shot that my rpms will stay between 5400 and 6300 (6300 is where the governor is set up to shift)all the way down the track which will keep me right in the sweet spot. Not so good for a TPI though. In light of Beach Bum's experience maybe you can go to a higher stall with a TPI if it is a very tight converter. Just don't do it with my converter!!!
	Posted on: 2008/11/21 0:25
	_________________ ´89 Vert, 383, 230/236 cam, AFR 195's, LT Headers, HSR intake, 2800 stall, Zex 200 shot, ET Street Radials, tune by me. Runs were with D36 3.07's. On spray, 10.55 @ 132.78, 1.55 60 ft. On motor, 12.08 @ 113.15, 1.66 60 ft.
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WW7	Re: How much HP will I get by porting intake?	#17
Senior Guru Almost Heaven WV 268 Posts Member since: 2007/9/7 0:00	Quote: Blade_1 wrote: Just noticed you got a wing. That's good for about ... oh ... I'd say 600 HP (about). Dude,I have the whole Greenwood Package.From what I understand it was done as a factory option and is way better than 600hp. I want to thank you all for the input,Im not sure yet what Im going to do but you sure gave me a lot of options..WW
	Posted on: 2008/11/21 0:43

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Schrade	Re: How much HP will I get by porting intake?	#18
Elite Guru eastern NC / e-i-e-i-o 1909 Posts Member since: 2008/8/15 2:01	Quote: dan0617 wrote: Quote: Blade_1 wrote: Just noticed you got a wing. That's good for about ... oh ... I'd say 600 HP (about). Don't believe anything Blade1 says. I installed that same wing and only got 598 horsepower. That about 600 number is a bunch of 598? You're gettin' too much drag. Get the special accelerator effect: Should bring you up by a deuce on the dyno!
	Posted on: 2008/11/21 1:34
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dan0617	Re: How much HP will I get by porting intake?	#19
Senior Guru Tyrone, PA 1260 Posts Member since: 2007/12/30 0:00	I KNEW that big fan in front of my car while it was on the dyno was slowing me down and costing me horsepower. I'll try your suggested product and then I'll be there. Also, next time I dyno I'll make sure they turn the fan off and then we shall see.....600 club, here I come!
	Posted on: 2008/11/21 1:47
	_________________ ´89 Vert, 383, 230/236 cam, AFR 195's, LT Headers, HSR intake, 2800 stall, Zex 200 shot, ET Street Radials, tune by me. Runs were with D36 3.07's. On spray, 10.55 @ 132.78, 1.55 60 ft. On motor, 12.08 @ 113.15, 1.66 60 ft.
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Schrade	Re: How much HP will I get by porting intake?	#20
Elite Guru eastern NC / e-i-e-i-o 1909 Posts Member since: 2008/8/15 2:01	Quote: WW7 wrote: Quote: Blade_1 wrote: Just noticed you got a wing. That's good for about ... oh ... I'd say 600 HP (about). Dude,I have the whole Greenwood Package.From what I understand it was done as a factory option and is way better than 600hp. Sure is uh huh ! 'Bout 601.
	Posted on: 2008/11/21 1:51
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cuisinartvette	Re: How much HP will I get by porting intake?	#21
Elite Guru 1782 Posts Member since: 2005/9/16 0:00	[QUOTE]I KNEW that big fan in front of my car while it was on the dyno was slowing me down [/QUOTE] LMAO!!
	Posted on: 2008/11/21 4:31
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cuisinartvette	Re: How much HP will I get by porting intake?	#22
Elite Guru 1782 Posts Member since: 2005/9/16 0:00	TPI stuff Plenum, base and AS&M runners with a qucikie job on them [IMG]http://img.photobucket.com/albums/v224/kalthoff1/141_4125190.jpg[/IMG] [IMG]http://img.photobucket.com/albums/v224/kalthoff1/141_411616.jpg[/IMG] For the new 383 [IMG]http://img.photobucket.com/albums/v224/kalthoff1/141_411716.jpg[/IMG] [IMG]http://img.photobucket.com/albums/v224/kalthoff1/26.jpg[/IMG] In the middle are the stock ones, found where the tube meets the flange the hard way, broke through a tiny bit. Nothing that cant be fixed though. Looks from the outside like theres plenty of room, not so. See red circle, tiny crack showing [IMG]http://img.photobucket.com/albums/v224/kalthoff1/141_4119189.jpg[/IMG]
	Posted on: 2008/11/22 2:01
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BrianCunningham	Re: How much HP will I get by porting intake?	#23
Senior Guru Boston, MA for the most part :) 7763 Posts Member since: 2007/12/30 0:00	I always wondered why noone came out with D shaped runners.
	Posted on: 2008/11/22 18:26
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