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View Full Version : which head is better "G" or 782



turbovan89
05-29-2006, 12:22 AM
I picked up a G casting head some time back because I heard that it can really wake up a 2.5 tI. My van will be down for a tranny rebuild so I thought that this would be a good time for a head swap. Now I have read that the "G" is not necessarily the way to go. Here is what I have:

T3/T4 .63 trim
Stock tI intake
choice of stock or 3.8 minivan TB (56mm?)
tII IC
FWD-P stage 5 cal
3 bar map
+40s
AFPR
TurboXS MBC


OK which head do you think I should go with. What are the adv/disadv of each head. Also I have no idea which cams are on either head. I'm not sure how to tell, but I will have a look tomorrow on the "G" head. Thanks in advance.

Deric

boost geek
05-29-2006, 12:28 AM
Do you have the intake for the 3.8? If you do, cut off the elbow as long as you possibly can and weld it up to your 2.2 intake. One of the best mods you can do in my opinion.
I dont have enough info to give an opinion for which head to use for a 2.5 and heavy vehicle.

turbovan89
05-29-2006, 12:40 AM
Do you have the intake for the 3.8? If you do, cut off the elbow as long as you possibly can and weld it up to your 2.2 intake. One of the best mods you can do in my opinion.
I dont have enough info to give an opinion for which head to use for a 2.5 and heavy vehicle.

Really. I don't have the intake but could probably get one easily. I have a spare tI intake I could try this with. Besides my wife loves any excuse she can to use her new welder. Thanks for the tip. Also just noticed same question in thread titled "head games". I'll follow that on as well for the answers I'm looking for.

Deric

turbovanmanČ
05-29-2006, 12:59 AM
Personally, a good ported 782 head is better. Cutting off the elbow is proven not to really do anything. 58mm is useless unless you get rid of the other restrictions, and you better have alot of money. I saw your thread on the other site and see you are using a Stage 5, I believe thats setup for a 782 head. Run that on a G-head and it will be dog. Also, stage 5 requires high octane gas all the time, otherwise boom.

turbovan89
05-29-2006, 05:42 PM
Personally, a good ported 782 head is better. Cutting off the elbow is proven not to really do anything. 58mm is useless unless you get rid of the other restrictions, and you better have alot of money. I saw your thread on the other site and see you are using a Stage 5, I believe thats setup for a 782 head. Run that on a G-head and it will be dog. Also, stage 5 requires high octane gas all the time, otherwise boom.

OK, apparently I need to keep the 782 head as it works best w/stage-5 cal. I do plan of going to a powerstroke IC, and I will port or have the 782 ported while doing tranny rebuild. What should I do for intake? what other restrictions do I need to take care of? I forgot to mention that I have, I think, 2.5" SV and (for sure) 2.5" exhaust (no cat, bullet muffler). Also I have a spare carbed 2.2/523 I was thinking about building an all motor:eyebrows: . Will the G be a good canidate for this or should I just sell and use the money for something useful?

Thanks,

Deric

Whorse
05-29-2006, 05:55 PM
I think that the swirl heads are very easy to mess up by porting. I was looking into it myself and since I've never done it I figured it's not worth it. Easy to ruin the swirl characteristics.

boost geek
05-29-2006, 09:25 PM
If your running a large intercooler, your intake will be a restriction, unless you wanna spend $100-150 on a 2 piece . I'm glad I modded my 1 piece, running a larger t.b. on a stock 1 piece is a waste of time. You can see the size difference on the pic.
If you have a tig welder, I say go for it.

turbovanmanČ
05-30-2006, 01:20 AM
OK, apparently I need to keep the 782 head as it works best w/stage-5 cal. I do plan of going to a powerstroke IC, and I will port or have the 782 ported while doing tranny rebuild. What should I do for intake? what other restrictions do I need to take care of? I forgot to mention that I have, I think, 2.5" SV and (for sure) 2.5" exhaust (no cat, bullet muffler). Also I have a spare carbed 2.2/523 I was thinking about building an all motor:eyebrows: . Will the G be a good canidate for this or should I just sell and use the money for something useful?

Thanks,

Deric

Steve aka Direct Connection tested both the one piece and 2 piece intakes on a stock head and there virtually identical, except the one piece has a higher torque peak so I believe its better for ligher cars, the 2 piece shifts it lower so its better for a van. I picked up serious vacuum with a ported head, 2 piece and log header. I think all bets are off with a big ported head and the 2 piece shines. BTW, I have one for sale, :eyebrows:
I would port the stock ex manifold, get the 3 inch sv and dp and your off to the races.

John B
05-30-2006, 10:31 AM
I'm glad I modded my 1 piece, running a larger t.b. on a stock 1 piece is a waste of time. You can see the size difference on the pic.
If you have a tig welder, I say go for it. How does the two-piece neck compare to the one piece?

glhs875
05-30-2006, 10:42 AM
From what I've seen a 782 head starts to hit a brick wall in the mid 20 psi range due to detonation issues. Huey in his Omni, was dentonating in this range on pure race gas. I have had problems as well, and I know of others that have had the same problem. And if tuned right, a G head can have TONS of bottom end torque. That's just my opinion. For an 8V, I won't run anything but a G!

glhs875
05-30-2006, 10:46 AM
How does the two-piece neck compare to the one piece?

It's alot larger in diameter. The runners are 2 to 3 inches longer on a 2 piece. I feel like the runners coild be a little shorter on the 2 piece. I measured them to be 12" including the upper.

turbovan89
05-30-2006, 11:26 AM
From what I've seen a 782 head starts to hit a brick wall in the mid 20 psi range due to detonation issues. Huey in his Omni, was dentonating in this range on pure race gas. I have had problems as well, and I know of others that have had the same problem. And if tuned right, a G head can have TONS of bottom end torque. That's just my opinion. For an 8V, I won't run anything but a G!

A discenting opinion,I love it. I do plan on running a lot of boost 20-25psi at times. I noticed in your sig your 1/8th mile times do you go to huntsville dragway, I've been there a couple of times (used to live there). What cal are you using? That might be the main reason everyone else is telling me 782, because of my FWD-P stage 5 cal. I will be in Gurley over the 4th will you be around?

Thanks,

Deric

John B
05-30-2006, 11:55 AM
It's alot larger in diameter. The runners are 2 to 3 inches longer on a 2 piece. I feel like the runners coild be a little shorter on the 2 piece. I measured them to be 12" including the upper.

I was surprised that the two piece wasn't really any better than the one piece in the flow testing. I wonder if opening the two piece to 52 mm would make a big difference?

John B
05-30-2006, 12:00 PM
From what I've seen a 782 head starts to hit a brick wall in the mid 20 psi range due to detonation issues. Huey in his Omni, was dentonating in this range on pure race gas. I have had problems as well, and I know of others that have had the same problem. And if tuned right, a G head can have TONS of bottom end torque. That's just my opinion. For an 8V, I won't run anything but a G!

I'm pretty sure Steve Menegon was running a swirl on Sledgehammer when he broke into the 11s. He does some chamber work on the 782s that reduces detonation.

turbovanmanČ
05-30-2006, 12:28 PM
John, remember the testing was done with a stock throttle body and stock head. Get a ported one and all bets are off.

As for Swirl vs G head, talk to SMP, he used both and went faster on a 782 head, when he was running the 8 valve setup.

The elbow is a moot point, lots of people have made it larger and had zero gains.

John B
05-30-2006, 12:38 PM
What made the comparisons problematic is that the one-piece was opened up for a 52mm while the two-piece was 46mm.

glhs875
05-30-2006, 04:04 PM
A discenting opinion,I love it. I do plan on running a lot of boost 20-25psi at times. I noticed in your sig your 1/8th mile times do you go to huntsville dragway, I've been there a couple of times (used to live there). What cal are you using? That might be the main reason everyone else is telling me 782, because of my FWD-P stage 5 cal. I will be in Gurley over the 4th will you be around?

Thanks,

Deric

Iam using a bone stock 86 T1 5 speed cal. Look me up! ( phone# 256-587-6093) ask for Brian. Gurley is only about 15 min away. Yes, I go to Huntsville Dragway some, although the run on my sig was ran at Sand MTN. Dragway. I plan on going to Huntsville soon, everyone usually runs 2 to 3 tenths better at Huntsville between the two. I have dialed in more boost, I may have to put in a 4th stage of boost for 3rd gear, to keep the tires from breaking loose in 2nd gear, and I plan on crushing my best ever pure street time of 8.59 @ 82mph which was run at Huntsville.

glhs875
05-30-2006, 04:06 PM
I'm pretty sure Steve Menegon was running a swirl on Sledgehammer when he broke into the 11s. He does some chamber work on the 782s that reduces detonation.

Yea, I've seen his work. No more fast burn on those heads. Might as well be a G!!

glhs875
05-30-2006, 04:09 PM
John, remember the testing was done with a stock throttle body and stock head. Get a ported one and all bets are off.

As for Swirl vs G head, talk to SMP, he used both and went faster on a 782 head, when he was running the 8 valve setup.

The elbow is a moot point, lots of people have made it larger and had zero gains.

That may be so, but did both heads flow identical etc, etc. And from what I've gathered, you hit that brick wall I was talking about, and in the mid 20psi range like I said.

glhs875
05-30-2006, 04:15 PM
After a good porting job on either head they are basically the same except for the combustion chamber. Do away with the fast burn characteristics of the swirl like alot of people do, and there even closer yet.

turbovanmanČ
05-30-2006, 04:43 PM
That may be so, but did both heads flow identical etc, etc. And from what I've gathered, you hit that brick wall I was talking about, and in the mid 20psi range like I said.

No brick wall, just getting started, :thumb:

I have seen a Steve M head up close, its still a swirl head.

glhs875
05-30-2006, 04:54 PM
I'm pretty sure Steve Menegon was running a swirl on Sledgehammer when he broke into the 11s. He does some chamber work on the 782s that reduces detonation.

On my Daytona, (2800+lbs. race weight) with the same exact 445 casting head which is now on my GLHS, that car would run consistant 8.20's @ 90+mph on DOT's, babying it out of the hole and with the boost staged for traction. Boost was at a high of 26psi, and I was only using 93 octane. In other words that car was a mid to low 12 second car in street trim. And with the boost unstaged and with slicks a high 11 second car (mid to high 7's -1/8th) still on pump gas. Throw in some race fuel, up the boost to 30+ and who knows?

glhs875
05-30-2006, 04:58 PM
No brick wall, just getting started, :thumb:

I have seen a Steve M head up close, its still a swirl head.

You need to read my last post and see if anyone can run that kind of boost on a swirl with only 93 octane and with no knock retard in mid to high 90 degree outside temps!!

turbovanmanČ
05-30-2006, 05:01 PM
You need to read my last post and see if anyone can run that kind of boost on a swirl with only 93 octane and with no knock retard!!


Guess you haven't seen Aaron Miller's car, forgot his name on here but he's laying down around 360 whp and over 300 ft/lbs on a swirl head and 93 pump gas.

Theres arguments for both heads, we could go back and forth for hours. Pick which head you prefer, I prefer the 782. Its made the most power, hands down.

glhs875
05-30-2006, 05:04 PM
Guess you haven't seen Aaron Miller's car, forgot his name on here but he's laying down around 360 whp and over 300 ft/lbs on a swirl head and 93 pump gas.

That's impressive. What kind of boost? And in what kind of heat? And what kind of numbers can his car run? Race weight?

glhs875
05-30-2006, 05:05 PM
Theres arguments for both heads, we could go back and forth for hours. Pick which head you prefer, I prefer the 782. Its made the most power, hands down.[/QUOTE]

That's the point Iam trying to make!!!

Frank
05-30-2006, 06:02 PM
I would never choose a 782 for a heavy vehicle supporting a 2.5L without a supper efficent intercooler, a GT turbo, etc. They are prone to detonate on inefficent heavy setups. Not all Steve's heads are swirl. I have a G-Head. Yes the 782 though makes more power... no question... I wouldnt recommend it in a heavy 2.5L.


Frank

GLHSKEN
05-30-2006, 06:04 PM
EXACTLY... Perfect outcome to this.... There is NO right answer. It depends on too many factors.

Aarons car (8valves) Has run 115 + in the 1/4 on street tires (5 sp no less). It's a full interior SC. I would say weight with Driver is 2600 or so. Now keep in mind he did this running 35 aspect 17's.... No where near traction...

I'll let him know about the thread... His car is VERY impressive

Brian, stock with +20's GLHS StageII zener and 3" exhaust I ran all day long at 18 (maxxed the stock turbo out) Ran a best of 8.44 @ 87.5 mph that way (on 23" m&H) 1.96 60'. For the 1/4 12.85 @ 109.7mph. I'd pull into the track and for insurance, mix 2 gallons of race fuel to my 1/4 tank. Just because I drove the hell out of it on the street and wanted to continue doing so.

That auto you run is a distinct adventage at the track. I just like rowing the gears :lol:

GLHSKEN
05-30-2006, 06:06 PM
I would never choose a 782 for a heavy vehicle supporting a 2.5L without a supper efficent intercooler, a GT turbo, etc. They are prone to detonate on inefficent heavy setups. Not all Steve's heads are swirl. I have a G-Head. Yes the 782 though makes more power... no question... I wouldnt recommend it in a heavy 2.5L.


Frank

EXACTLY... While some of the "fastburn" characturistics are removed, it's still a limited 782 design. The ring lands on the 2.5's are just too fragile to chance anything

glhs875
05-30-2006, 06:11 PM
I would never choose a 782 for a heavy vehicle supporting a 2.5L without a supper efficent intercooler, a GT turbo, etc. They are prone to detonate on inefficent heavy setups. Not all Steve's heads are swirl. I have a G-Head. Yes the 782 though makes more power... no question... I wouldnt recommend it in a heavy 2.5L.


Frank

The only way to prove which head makes more power would be first have them flow the same. And then have a programmable stand alone system to get the most out of each head up until detonation, and with both using the same fuel, and with both having the same compression ratio. Until I see that test like that with everything else on the combo remaining the same. Saying either head makes more power than the other IS A FALSE STATEMENT!!! That's my opinion!

glhs875
05-30-2006, 06:22 PM
The reason that alot of people end up making more power with a swirl over a G is that they are running alot closer to the point of detonation, which in turn will result in higher cylinder pressures, and of course will make more power. Turn the wick up on a G head, with either more timing, boost, compression, or all 3, and the results will be the same, which is increased combustion efficiency and increased cylinder pressure = (more power).

GLHSKEN
05-30-2006, 06:25 PM
You are dead on.. and I agree... Flow is flow

Biggest problem on the boards is "blind" following. Expecting the same result. Every car is different.

Frank
05-30-2006, 06:39 PM
The only way to prove which head makes more power would be first have them flow the same. And then have a programmable stand alone system to get the most out of each head up until detonation, and with both using the same fuel, and with both having the same compression ratio. Until I see that test like that with everything else on the combo remaining the same. Saying either head makes more power than the other IS A FALSE STATEMENT!!! That's my opinion!

This is true, however you can draw a conclusion based on peoples setups that swirls tend to make more power, however the most you can use is 'tend'... which I obviously should have used.


Frank

turbovanmanČ
05-30-2006, 07:39 PM
I need to find the info from SMP, he tested both and came up with the 782 ahead, :eyebrows:
But yeah, each car, van, cal, turbo, intake , air temp, altitude is different.

boost geek
05-30-2006, 09:07 PM
I missed Simon's last 2 outings to the track because my car after warming up would detonate so badly I couldn't even get into boost, just puttered it home after work. That's a 2.2 swirl (mexican), 12* or less T1 log. I put a Walbro 255 in, no change. The pistons and plugs were so loaded with white hard crap, took a while to clean the piston tops off with a drill and brass brush. Now I have the G head on again, Now I'm 13-14*, huge intercooler, 14 psi, no knock. I know the intercooler makes a huge difference, but i was pinging out of boost on the 782. Dont know why, but to me the G head is very forgiving, my other car had the same head, I didnt even have an A.F. gauge on it.

glhs875
05-30-2006, 09:41 PM
I need to find the info from SMP, he tested both and came up with the 782 ahead, :eyebrows:
But yeah, each car, van, cal, turbo, intake , air temp, altitude is different.

That would be interesting but, unless both heads used flowed identical, and if both heads were not tuned properly to the point of detonation and then backed off slightly, his findings wouldn't be all that accurate either.

I know I may seem like a butt, but on something like this I would have to see the facts, specs, and data with my own eyes to believe anything. I can't rely on words on a matter like this.