V8 Turbo Questions

[V6RACER]

As you may know, I have started the V8 build and have a few questions about the Rod/Stroke Ratios... Looking to make 1800~2000 hp :biggrin:


What should I shoot for when considering rod length and stroke in a SBC??

Right now the setup I'm looking at puts me at a 1.48:1 rod/stroke ratio. This is very similar to the SBC 400 ratio.

What opinions are there on this??

 

[tom robison]

you should get ahold of kip, he branches out inthe sbc world alot, he help me with my nasty ass sbc.

 

[Louie L.]

Jason,
I dont think it really matters. I was advised by more than one engine builder to build the proper piston for the application. Pick the crank then connect the 2 with what ever you are left over with.

 

[Dusty Bradford]

Jason,
I dont think it really matters. I was advised by more than one engine builder to build the proper piston for the application. Pick the crank then connect the 2 with what ever you are left over with.

Exactly.

9.02 deck or tall deck?

With a 9.02 deck you can get a 383 or 400 ci with a 3.75 stroke. I have a 6.0 rod so it's not the ideal piston design but it works. If I started over I'd go 5.7 or 5.85 rod. Just make sure you buy the crank for the correct rod. You can't put a 5.7 rod on a crank made for a 6.0.

 

[V6RACER]

Exactly.

9.02 deck or tall deck?

With a 9.02 deck you can get a 383 or 400 ci with a 3.75 stroke. I have a 6.0 rod so it's not the ideal piston design but it works. If I started over I'd go 5.7 or 5.85 rod. Just make sure you buy the crank for the correct rod. You can't put a 5.7 rod on a crank made for a 6.0.

It's a tall deck (9.325") Looks like I will have to go smaller on the stroke and reduce the cubic inches or change the rod size to get the cubic inch I want with a lower rod/stroke ratio.. I just wanted to make sure there were no issues with a low rod/stroke ratio in high HP engines.

 

[it's just a six]

Maybe Tom will give you an answer?
Nelson Racing Engines - "We Build Horsepower!"

 

[Dusty Bradford]

It's a tall deck (9.325") Looks like I will have to go smaller on the stroke and reduce the cubic inches or change the rod size to get the cubic inch I want with a lower rod/stroke ratio.. I just wanted to make sure there were no issues with a low rod/stroke ratio in high HP engines.

I wouldn't be worried about ci. As long as you can go 400-421 you will make plenty of power.

Go either 3.75 or 3.85 with a 6 inch rod and that will give you a good piston. The fastest pass in our class was made by a 408 or a 412 ci motor.

 

[malibuick231]

Dusty why dont you like the piston for the 6in rod? Thats what I was about to buy for mine. The piston is a off the shelf piston from je with a 23cc dish. Should I not use this set up?

 

[Louie L.]

Dusty has a specific set of circumstances he has to deal with using the SB2 head. The chambers are small, and his rods are long, making piston design complicated.

With a regular 23 deg head, that doesnt matter nearly as much. I also have an off the shelf JE piston in mine.


Jason, Have you chosen a cylinder head yet ? Thats where the HP is @.

 

[V6RACER]

I wouldn't be worried about ci. As long as you can go 400-421 you will make plenty of power.

Go either 3.75 or 3.85 with a 6 inch rod and that will give you a good piston. The fastest pass in our class was made by a 408 or a 412 ci motor.

I want to be able to make more power I'm trying to get around 440 cu in and keep it strong enough for the abuse. 4.125" bore X 4.125" stroke X 6.0" Rod. That will get me around 1.2625" above the piston pin for rings..

Jason, Have you chosen a cylinder head yet ? Thats where the HP is @.

Still searching for the best bang for the buck. CFE, RFD, AFR, etc.... Choices, choices..

 

[EightSecV6]

I like a 6" rod and a 3.75" stroke.

 

[Dusty Bradford]

Dusty why dont you like the piston for the 6in rod? Thats what I was about to buy for mine. The piston is a off the shelf piston from je with a 23cc dish. Should I not use this set up?

What Louie said. If you get into cylinder heads with small chambers piston design is an issue. I got lucky with mine. I was very close to having to swap crank and rods to get a decent piston. I can not run an aluminum rod, there's not enough room between the pin and the top of the piston.

 

[Dusty Bradford]

I want to be able to make more power I'm trying to get around 440 cu in and keep it strong enough for the abuse. 4.125" bore X 4.125" stroke X 6.0" Rod. That will get me around 1.2625" above the piston pin for rings..



Still searching for the best bang for the buck. CFE, RFD, AFR, etc.... Choices, choices..

The heads and cam will get you much further than 20ci will. With a tall deck I'd go no bigger than 417-421.

My set-up and Stack's is a good example. He's 438, I'm 400 yet I can run the same mph he can with 2#'s less boost with the same heads. The cubic inches aren't doing anything. I have seen some new turbo small blocks running the 114mm with a 9.5 deck block so they can get around 449ci. Yet, most of the record setting small blocks have always been closer to 400ci. If it's all the same price, the bigger motor would be smarter but I don't think you'll gain much power at all.

 

[V6RACER]

I like a 6" rod and a 3.75" stroke.

Billy, it's a V8 not a little V6 lol

 

[V6RACER]

The heads and cam will get you much further than 20ci will. With a tall deck I'd go no bigger than 417-421.

My set-up and Stack's is a good example. He's 438, I'm 400 yet I can run the same mph he can with 2#'s less boost with the same heads. The cubic inches aren't doing anything. I have seen some new turbo small blocks running the 114mm with a 9.5 deck block so they can get around 449ci. Yet, most of the record setting small blocks have always been closer to 400ci. If it's all the same price, the bigger motor would be smarter but I don't think you'll gain much power at all.

How would a 106 do on a 400 cu in?? That's why I was thinking larger cubes so I can hang a 106 on it and run outlaw when I'm not running EZ.

 

[Dusty Bradford]

How would a 106 do on a 400 cu in?? That's why I was thinking larger cubes so I can hang a 106 on it and run outlaw when I'm not running EZ.

That's where the cam comes in. With my first cam I could barely spool the 94. With the new cam I can actually go to a 1.32 a/r with the 106 and still be OK. I could go in the lights with 12# of boost with the 94mm at 3600 rpm. If you saw my runs in Reynolds you saw how quick the 106 came up. It was no problem.

Since your starting from scratch the bigger motor probably won't be any more expensive so I'd go for it. I just wouldn't push it to the point where your having to run a shorter rod on a long stroke.

 

[malibuick231]

Dusty I know you dont want to give your cam spec's but can you tell me who did your cam because I am going to need one for my new engine and might need some help with it.

 

[Underboost]

Have you guys ever heard of Nelson Racing Engines? They build some sweet $h!t. Check it out NRE TV by Nelson Racing Engines - "We Build Horsepower!"

 

[S2V6RACER]

Have you guys ever heard of Nelson Racing Engines? They build some sweet $h!t. Check it out NRE TV by Nelson Racing Engines - "We Build Horsepower!"

A little pricey.

 

[Underboost]

A little pricey.

Just A Bit. :tongue: