598 Stroker Combo

[67Firebird]

I recently purchased a Dart Big M 4.6 bore. I am looking to build a 598 blower motor with a 14-71 on Race Gas. I am looking to produce about 1400 - 1500 HP.

Can anyone recommend me a good crank, rod and piston combo that will put the least amount of stress on the cylinder walls as far as the piston skirt goes.

And please recommend manufactures for the parts...

Thanks!

[want-a-be]

What deck height block did you get? What does it actually measure before you have it decked? If it's a 10.2,... and hopefully Dart gave you a little to deck off from there. I'd look for around a 6.7 rod. Piston pin height is pretty easy to figure from there with the stroke you decide to go with.

Will be glad to answer any questions you have if you need the help.

Don

[Awesome Bill]

the very least amount of stress is not what you should be worried about with that block. But, You can run the Callies, Crower, Lunati etc pro series 4340 internally balanced cranks with the ¼" keyways for the blower hub and run and a 6.7" Oliver rod with a 1.250" c/h piston for a 10.200" deck or even less stress on the cylinder wall is a 6.8" rod with a 1.120 c/h height piston yeilding 10.170" c/h and you have room to put the piston any deck height from that to 10.206" I also use the Groden Billet Aluminum Rod that is the best in the business with the blower if you wanted to. You do not need to do this with any blower application. Someone years ago figures you have to run aluminum rods with blowers? You don't. You eliminate the service of the aluminum rods after so many runs with the steel rods. No it does not ring the crank any different in this application. Hope this helps. I have those cranks on the shelf if your interested in Callies Pro Magnum Series.

[67Firebird]

Thanks for the replies...

I have the tall deck block. How do I measure the block correctly to determine the actual true deck because Dart said they may very a few thousands..

I am not really worried about the block breaking, I guess my main concern was pulling the piston deeper into the block exposing more piston skit and causing additional pressure / ware over time on the lower cylinder walls and piston skirt.

And can someone tell me were to get the oil pump dowel? I called dart and they do not carry them and JEGS told me they only have them for the Dart Little M.

Thanks!

[67Firebird]

Hey Awesome Bill,

Where can I get some pricing on your cranks? And do you have rods and pistons?

Thanks!

[67Firebird]

Hi, one more question...

What static compression ration would you recommned for this application? I plan on running the Dart Iron Eagle Head with the 345cc Intake Runners.

Thanks!

[want-a-be]

Do you already have the heads? I think a friend of mine who also lurks on the Dart Board has a set that is too much for his combination.

Don

[Awesome Bill]

Hey Awesome Bill,

Where can I get some pricing on your cranks? And do you have rods and pistons?

Thanks!
Just give me a call @ 302-436-4200, ask for Bill, I'll shoot you over some prices from really good stuff that works very well to the really inexpensive stuff that still works well in this particular application. Every thought about running alky. Make a ton power.

[67Firebird]

Do you already have the heads? I think a friend of mine who also lurks on the Dart Board has a set that is too much for his combination.

Don

Not yet. I am planning on getting them soon. What does you friend want for them and what kind of condition?

[67Firebird]

Hi Bill,

I have thought about Alky, because I am in FL and the humidity is crazy here I understand it can be a pain to deal with. I hear it is also hard on fuel systems. That's the reason why I am going to a 14-71 on a 598. I wanted 1400-1500 HP on racing gas because my car is certified for 7.50 and I am trying to get as close as I can to that.

Alky on that 598 with the 14-71 might blow up my tranny which is rated for 2000 HP. And I do not want to get into the billet cranks, too much money.

This is just a fun go fast car. I am not looking to get into any real competition racing. I just have a need for speed and I like building cars...

[want-a-be]

Alky does have it's idiosyncrasies for sure. But none that are really hard to overcome. Thing about Alky is,... it loves compresssion. HP is usually pretty much the same, but it will increase. The Torque peak will increase more then the HP peak will.

I'll check on the heads for you.

Don

[Awesome Bill]

Actually alky does not love compression, its just that with alky you can keep detonation to a minimum and you can make more compression with twice as much fuel on bottom end rpm. This is why alky down low you make more torque. But the suggestion alky loves compression is really untrue and alky will never make as much power as gasoline with a carburetor on the top end? This is going to start a fight. lol! Fuel injection is a different story.

What we do know is that air and fuel make power, not compression. Now compression without the proper fuel makes a mess. With alky and low compression and a blower, now you can make some power. With 30-40 lbs of boost and 8-1 compression, you can make some really safe power with a window for error about as long as a ruler.

Start with 12-1 compression and go with 20 or even 25 lbs of boost and you will not make as much power and your window of error gets really tight. AIR AND FUEL MAKE POWER NOT COMPRESSION. High compression can only make power with the proper fuel, or slower burn rates and stability is a factor with all fuels.

That is why not all race fuels make the same power in the same applications. For example, I just spent 1 full day dyno testing a 434 with 15-1 compression and C12 made the most power @ 710hp and 6800 rpm w/34° total timing. We just went and put some Q16 oxegenated fuel in her just to see and we lost almost 15 hp and the EGT's went over 1450° with the exact same tune up.
Can anyone tell me why the EGT's went up and power went down?

This of course is on a real dyno and not some paper one. So when you get a real dyno, you'll be able to see these things that paper ones can't even think of doing. So even with the C12, which is on the boarder here, made more power. The burn rate for compression and rpms fit the application better. AF ratio was 12-1 and the VE was only 96%. This is with mufflers and air filter. I could of changed timing to 36-38° and most likely the hp would of come back with the Q16, but that good of a fuel would be over kill and hard to get @ any track. Either way, I find some people who think just because you put better fuel in, change over to alky on even low compression engines, even stock engines, they tend to think it will run better. Most times it slows you way down. As I have said, application and complete package is the key. Most people do not even know what their base staic compression is to start with!

[Elkyman]

Hey Bill,

I'd like to take a stab at your question in your last thread, the reason the egt's got hotter, and the power went down was due to the fuel used, and the amount fed to the engine. From what I have red, this oxygenated fuel, like it says, has more oxygen in it thus you need more of it to make the same power, kind of like pure Methonal which most know, more volume of alky is needed due to the demands of the buring process and the alky's burning properties. Doesn't the specific gravity of the fuel also play a roll in the power levels in engines?, this is also something I have red about that the Octane number is not the best way to buy fuel, but to do the caculaton with your compression ratio and design of the engine combo being used. I would just say, that after switching to the oxyg. fuel, you basically leaned it out and had more oxyg. to fuel! One would think that the power would go up if the fuel ratio is leaned out up to a point, and maybe you went past that point, but who am I.????:) Am I even close to the right answer??????

[want-a-be]

Nah Bill,...I'm not intrested in revisiting that debate with you again. We already went around on that one. I've gained some better respect for your opinions as I'd like to think you may have for mine.

Don

[Awesome Bill]

Your right if the a/f ratio was correct. If I was running the perfect jet size with say c16 race fuel and then I put the Q16 oxegenated stuff in it, I would then be running on the lean side. But if I was on the rich side, I would most likely make a little more power being the fuel leans it out.

As far as alky and carbs, they do very well but who know how much power you can get from 2 neddle and seats with alky? Any guess Don? Not much

Alky has a BTU that is half of race fuel so it takes twice as much. Any time you remove displacement in the intake and heads you loose power and VE. If your injected, you can gain a lot in some case. The only reason you would ever make more power with alky using a carb is when you had a very bad carb and you got a good alky carb matched pretty close to what you needed. But if you got a properly jetted and tuned gas carb, you will always make more power with naturally aspirated engines. You may have to hunt a little but gas makes more power and takes up less space so there is always room for more air and fuel with the proper a/f ratio. Its simple if you think about it.

With blowers, you will always make more power with alky carbs or injection than gas because the alky will super coold the air and fuel from the carbs to the intake valve. You can always count on that. So with the super cold air using alky, you can not even get close to the temp of the gasoline air with a blower. It is always hot. Even turbos with gas have to super freeze the air to make power. Turbos with alky injection now get to throw away the freezer they had to use with gas. Alky of course now uses twice as much fuel so with the killer 2000 hp and up engines, where a/f's are 3-4 to 1, you have to use over 200lb per hour twin injectors for each cylinder.

No debating on this one Don your right about that. We run the 9-1 rule NE modified division for a couple years and ran away with the alky 650 carb ruled engines. The reason was only becuase we could keep our engine right @ 190° at all times. This in fact made more power than gas engines going well over 220°. Either way its only what you do with it.