4g64 Head And Valvetrain Questions...

[v8klla]

I recently acquired a 95 GSX and was planning on using the 2G head for my project. I saw that Vicious is using a 1G head and I was just inquiring as to the reasoning behind this? Larger ports?

Also is it a good idea to upgrade the valvetrain in a 4g64, due to the fact that it will rarely if ever see over 8000 rpms? Or maybe vicious plans to go higher? I am looking into oversized valves, but was wondering if springs and retainers would provide any performance gain?

Also, assuming all goes well and this thing gets built, will an ACT 2600 hold the power or should I look into a 2900? How would daily driving be with a monster clutch like that?

Vicious, Jet, Steve, Shane I know you guys have to have some input on this!

Thanks ahead of time for the info!

Chris

[Emcee gsxtc]

the 2600 is stiff but i adjusted to it, many of my friends (mostly civic drivers) say it is too stiff to drive with but i enjoy it, of course im 6'2" and like 250lbs. Personally i wouldnt say its all that bad.

[AJ]

Originally posted by v8klla@Feb 11 2004, 11:32 PM
How would daily driving be with a monster clutch like that?


Easy with a 2600. YOu know the size of me and I have chicken legs. I had no troubles with my 2600 in my old 95 GSX. Sure, sitting in stop and go for an hour can get tiring, but that doesn't happen all that much.

Power wise what #s are you looking for? 500 on race?

[FORSFED]

Chris, if you ever get the chance to compare a 1g and 2g head, you'll see a night and day difference as the ports are much larger and it'd take a lot of time to get a 2g head to that same point. Many will say that the 1g head is good for up to 500hp in stock form. Whether that's true I cannot say for sure. As for the valve train I think they are about the same between the two.

If you decide to upgrade the valvetrain, oversized exhaust valves are a good idea to help get more exhaust out with every stroke. If you plan on having it be a higher rev motor you'd probably wan't to consider new springs and retainers and especially if you're doing valves you're that far anyway. Having a strong head is one of the most important aspects in my opinion as to acheiving high hp goals.

About the clutch, I think the 2600 is great. After driving commercial trucks all day long, the 2600 doesn't feel all that tough as so many people talk them up to being. I don't know anything about the 2900 except JET planned on running one until he found out about his motor.

Most of this is just my opinion, so take it or leave it as you wish, but maybe it'll help.

-Steve

[v8klla]

I am not worried about the 2600 really, more so about the possibility of a 2900. As far as how much power I would like to make, well the sky is the limit, or is it my checkbook?

I don't want to be unrealistic, but I would like to be into the 10's this coming year. I still see it as a longshot, but a definate possibility if everything goes well. So how much WHP would that be?

As for the head, I know the 1G ports are larger but had heard from Raptor that the 2G head is better in terms of air velocity?

And as far as the valvetrain, I guess if I am spending this much money on a car I may as well do everything right the first time...

Chris

[1ViciousGSX]

Ok here's the deal. I plan on 8500rpm limit with my motor. If you plan on going fast, get a 1g head period. There is an advantage with the 2g head if you are willing to spend plenty of money getting it ported. But you would have to spend probably another $800-1000 over the cost of a good 1g "race" port job to see any benefit. Oversized valves in a stock head would probably not do much to help. You would see more benefit with them if the head was ported to open up the valve pockets around the oversized valves. And if you are willing to spend that money, just do the springs and retainers. It's a good insurance policy against valve float. What ever you decide to do, be sure to put some good rods and light weight pistons in it due to the high piston velocities.

Are you planning a 1g or 2g 4g64?

As for the clutch question, everybody has their own opinion on which one to get, and we've all been down that road ;) . I like mine and I'm sticking with it (ClutchMasters 2500lb w/4 puck sprung hub disk). :razz2:

Peace,
1ViciousGSX

[JET]

I would go with the 1g head on a 2.4l. You will be flowing more air so the velocity of the head will be higher. If you keep the stock valves, the stock retainers and springs are ok too. If you put in bigger valves you will probably want upgraded springs and retainers because those valves will be heavier.

[Shane@DBPerformance]

You could just throw in some $115 Crower Springs into you head and more than safe to 8000RPMs.

You can make well over 500whp on an un-ported 1G head, it is just easier with a ported head and you will probably see a more aggressive power band past 7000RPMs with a ported head. I wouldn't be surprised to see an unported 2G head hit 500whp with a sheetmetal intake on it. You don't need ports big enough to fist to make a lot of power, the EVO 8 and turbo Hondas have proven that. If your going to run oversized valves,you might want to get a port job and valve seats to match them. It's hard to tell what the gains might be with them, the gains that people get from fully ported $1200 heads are sometimes hard to measure. Not a lot of people are doing before and after tests. I would be happy to see a 20whp gain with a well ported head on a DSM, they aren't like a crappy cast V8 head where a monkey could see how some basic porting could make a big difference.

ACT 2100 street disc all the way!

[v8klla]

Alright, well the 1G head sounds promising, and I will definately put some thought into valves and springs.

I am building a 2g 4g64, of the 7 bolt variety ;) I have Eagle rods and Wiseco pistons already, along with the block and crank. I need to get the machine work done and start assembling this thing. Besides some mitsu parts, I have pretty much everything for the longblock. Which cam gears did you go with, stock 4g64 DOHC or adjustable 4g63?

Jet, what have you heard about that 2900 and daily driving, I'm sure it is a bitch!

Thanks guys,

Chris

[1ViciousGSX]

Originally posted by v8klla@Feb 12 2004, 11:50 AM
Which cam gears did you go with, stock 4g64 DOHC or adjustable 4g63?


Adjustable 4g63 gears, but you will have to degree the cams in and make a new indexing notch on the adjustment scale. They will not line up correctly out of the box. 4.5-5 degree difference in either direction from 0 depending on how you line up the gears with the belt.