GN1 heads or Champion Ported Irons

[BUICKTR]

I have put some $$ away for some new heads. I am debating which ones to buy. I know the alum are lighter, but my goal is to have a good mid 10 second car. I have a rebuild blueprinted engine with ARP Rod and Main bolts, center billet main caps, TRW pistons, resized rods, 218/218 cam. I will also upgrade later in the year the fuel system to double pumper, 83 lb inj, FAST, T-70 turbo. As for the IC I have a 20 row stock location. Will it be a good investment to go Alum or will the Irons serve my goal. I'm just a little nervous when I hear alot of those GN'1's cracking.

 

[Intercooler]

Get some nice irons. I considered GN-1's at one point. Until I got feedback at the track from guys that switched back to irons due to cracks and leakage. A good set of irons will do what you want and save you some bucks to boot. My irons in the sig flow more on the exhaust than GN-1's with work done.

 

[Nick Micale]

Originally posted by Intercooler
....... My irons in the sig flow more on the exhaust than GN-1's with work done.

There is no way a stock, iron head with 1.50 valves [largest that will fit] is flowing more than a Champion alum head with 1.60 valves. The ports in the alum flow more un-worked than is possible to get from an iron head. The most bang-for-the-buck, alum heads with 1.90 intakes, 1.60 exhaust. Will flow,out of the box, better than ANY ported iron head. Have about 3 years of flow bench numbers to back up this statement.

Also, leaks and cracks are using 14 bolt pattern on the alum heads, not the stock 8 bolt.

Have seen a couple high $$$ iron heads crack between valves and you then have an expensive door stop. At least alum can be fixed.

 

[NJTurbo]

Are you saying that 8 bolt gn1's are better then 14 bolt gn1's?? i have a chance to but a set of gn1r's. Heads look bad ass, i chose to go this road and sell my S2 Heads due to the modifaction i would have to make to keep my ac and p/s and that stock look.

 

[Intercooler]

Originally posted by Nick Micale


There is no way a stock, iron head with 1.50 valves [largest that will fit] is flowing more than a Champion alum head with 1.60 valves. The ports in the alum flow more un-worked than is possible to get from an iron head. The most bang-for-the-buck, alum heads with 1.90 intakes, 1.60 exhaust. Will flow,out of the box, better than ANY ported iron head. Have about 3 years of flow bench numbers to back up this statement.

Also, leaks and cracks are using 14 bolt pattern on the alum heads, not the stock 8 bolt.

Have seen a couple high $$$ iron heads crack between valves and you then have an expensive door stop. At least alum can be fixed.

Just giving the cold, hard in ink flow numbers I got compared to the ones listed on Kevins site with a set of GN-1's with "econo port". Sorry if you don't agree Nick but these are the facts

 

[Nick Micale]

Originally posted by njturbo
Are you saying that 8 bolt gn1's are better then 14 bolt gn1's?? i have a chance to but a set of gn1r's

No, they are the same casting. The weak area is around the bolt area used for the top and bottom bolts where the "old design" cracked.

So, if you are using them on a stage II block, be sure they have been modified or are late design.

 

[NJTurbo]

Nick check these out? http://photos.yahoo.com/rob_crisafulli go to second page, let me know if these look okay from what you can see.

 

[Nick Micale]

Originally posted by Intercooler
Just giving the cold, hard in ink flow numbers I got compared to the ones listed on Kevins site with a set of GN-1's with "econo port". Sorry if you don't agree Nick but these are the facts

Yeah, there is a lot of "stuff" posted on the internet. Like I said, we have flowed these on our bench and have compared them.
No way I can be convinced you can push more air through smaller ports and valves.

Don't know where Kevins got his info or how it was posted, but his "facts" defy logic? I will stick with my documented info rather than "web info".

Certainly, real world performance proves the alum develop much more HP. The TSM class in BG was dominated by alum headed cars, and was over a second faster than the best iron ones.

 

[Intercooler]

Originally posted by Nick Micale


Yeah, there is a lot of "stuff" posted on the internet. Like I said, we have flowed these on our bench and have compared them.
No way I can be convinced you can push more air through smaller ports and valves.

Don't know where Kevins got his info or how it was posted, but his "facts" defy logic? I will stick with my documented info rather than "web info".

Certainly, real world performance proves the alum develop much more HP. The TSM class in BG was dominated by alum headed cars, and was over a second faster than the best iron ones.

I don't doubt they dominated. My irons are about at the limit. He tweaked them a little more after the numbers in the thread below but I didn't flow them again so I don't know how much if any I gained. The aluminum GN-1's are just getting started where mine are spent so with some work (as can be seen on Kevins tech page) they really take off. Most of us production block guys will probably never use all the benefit of a set of max GN-1's. My numbers are in this thread and so is a direct comparison to a set of heads Bill Anderson worked and flowed. We come out close so this is some real numbers from at least one well known (I am not you know!) rather than "web info". Enjoy!:

http://www.turbobuick.com/forums/showthread.php?s=&threadid=46512&highlight=head+flow+numbers

 

[BUICKTR]

Thanks for the info. I also would like to know if I would need to push the car harder with Iron heads to reach my goal of mid 10's than it would be with the Alum.

 

[Two Lane]

Yes, you would...The TSM cars prove the difference in alum. versus iron.

HTH

 

[REDS HOT AIR]

same flow #'s iron makes more power than alum...

mid 10's wont be hard with ported irons...i should be able to hit mid tens with a good launch and i only ported the bolws and gasket matched my heads to stock intake gaskes and i still have the factory valves in them

 

[Boost]

Mid to low tens on irons are realistic...

aluminums should be good for 60-70 +or- ponies than irons.

 

[Nick Micale]

Originally posted by BUICKTR
Thanks for the info. I also would like to know if I would need to push the car harder with Iron heads to reach my goal of mid 10's than it would be with the Alum.

First off, you need to be aware that mid-tens in Texas [and AZ],
is not the same as the sea level, good air numbers, that lot of East coast cars see. At 3-5000' density altitude, iron head, street car has a safe max about 10.90.

Take the same car to a place like BG where we were in May, and see 10.4 to 10.6. I did not dream this, it is what we have done and seen for many years. This past May a full-weight GN with alum head stock block from AZ verified what I just said.

Same build with GOOD iron heads will normally see 10.90's when the temp and air conditions are good for the desert.

 

[Two Lane]

Expanding Options

Nick,

The new aluminum head you are working on will be another option added to the "Ported Iron or GN-1" menu.

Could you elaborate on the specifics of how the new head improves on the GN-1?

Is it going to be a true dual-purpose street/strip head? Or is it an all-out piece not well suited to street?

Lastly, there are people ready & eager for aluminum heads now...how long would they have to wait for the new ones?

TIA!

 

[Nick Micale]

The T/A heads were longer in the design phase than expected. It was felt that since Ken Duttweiler was going to provide input, it was well worth the wait for his expertise.

These heads will definately be stronger than any Buick alum V-6 head. Mike has LOTS of alum head developement and production experience for years with the V-8 alum head, and that will be evident here too.

There will be an increase in flow over the old M&A design, but actual numbers will tell the truth. Looks good on paper, but will only quote numbers from actual flow work.

Should be one basic casting for 8-bolt and 14-bolt heads. I have pushed very hard for the 8-bolt version [street] to use stock-type rockers, or of course exsisting roller rockers. The 14-bolt version will use a girdle, or plate type, roller rocker only. Scorpions are not being considered at this time.

With the design now being finalized, we are hoping to see heads available this fall. Just in time for that "winter" project!

Of course, as work proceeds, will keep all informed.

 

[KEVINS]

Originally posted by Nick Micale
Don't know where Kevins got his info or how it was posted, but his "facts" defy logic? I will stick with my documented info rather than "web info".

The info can be seen here and was donated. These are not my flow numbers just info that was gathered.

http://www.geocities.com/kdslaby/Tech_Page_Glossary.html

ks

 

[azgn]

it will take the same HP to run a given MPH....how you get there may vary.....GN1's will make more power with less boost; more boost required with less efficient heads...let's face it, if you are running into the 10's on a 109 block, you are most definitely "beating on it", be that at 24 lbs boost or 30lbs (you are making 600+ HP out of 231 cu.....pumping losses aside)

as Nick says, sea level and nice air makes one hellofa difference
( ask Jace about Las Vegas vs BG.......)

 

[S2V6RACER]

Originally posted by BUICKTR
Thanks for the info. I also would like to know if I would need to push the car harder with Iron heads to reach my goal of mid 10's than it would be with the Alum.

I ran 10.60's with 24psi at 125MPH with a 1.5 60'. I have cranked it back up to 29psi and honestley feel that if I keep things in check it will run for quite some time. My irons are studded and o-ringed and are holding up fine. Hopefully getting the NC convertor back this week and can hope to shed some more time.

Nick, I wouldn't question the Alum's being a advantage


As far as the 8 bolt alums, ask Dave Bamford how his are holding up and for how long. That says enough for me.



Ted

 

[turbov6joe]

Champ irons are nothing more than CNC ported OE style heads. I would go with the GN1's and benefit form the less weight, larger valves, relocated plug holes, better combustion chambers, and better overall design. I've heard that they finally worked out all the problems with the old design (leaking, cracking etc...). On the other side, many folks have gone in the 10's with messaged stockers, it's just easier to get there with the better heads.

Later,