[dci]

I seen here were Scott asked if anyone has made 2.3 HP per cube. My question is. What does it take to make 2.3 or more HP per cube? I want to clarify first I have not made 2.3 HP per cu. in. So I am not asking this to offend anyone.I just want to see what others have done or might think it takes. I think to make 2.0 HP per cube takes way more than the average guy is willing to spend or to make the effort to achieve. I have been fortunate enough to have seen some of what it takes to make 2.8-2.9 HP per cube in pro stock, and let me tell you. I do not have the funds or time to dedicate to such an endeavor. It gets way more involved at this level than I think most realize. Let's see what everyone's thoughts are. Let's use a 500 cubic inch limit with our current deck height of 10.240" and the cylinder heads that we have available right now. There are no limitations except the two I just mentioned. If the engine is capable of making a minimum of 2.3 HP per cube. Then this theoretical engine will make 1150+ HP. Let's not turn this into a cylinder head pissing match. I don't care what heads are used to achieve this goal. I just want to get people together to brain storm. We have some really smart guy's here and I think this will be of interest to everyone from the amateur racer all the way up to the professional level engine builder.




Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

[Transporter]

Don, I'm just curious why you are using a 500 cu.in baseline? I am assuming that it's because with our deck height it is easily achievable without getting into overboard stroke/bore dims.(IOW, a happy medium) or were you simply picking an easy to figure number that is equates to a class limit?

The only reason I am asking is it "seems" easier to get closer to or exceed your 2.3 number with a smaller cu.in limit as you are not asking for largest gross hp numbers, but a specific hp per cube number.

The only reason I say this is because of the number of small cube motors (other makes) that already exceed this number.

Not trying to confuse the issue or taint your thread, just asking.

Thanks Stan

[mike leech]

prostock as a baseline for hp per cube I assume

[Transporter]

Originally Posted by mike leech

prostock as a baseline for hp per cube I assume

That is what I was guessing as well Mike, I guess what I was really getting at is would it be "easier" (relative term) to get to 2.3 with a 400 ci motor at 920, vs a 500 at 1150?

[dci]

Actually I just picked a number that is easily attainable with a Pontiac engine. Cubic inch really does not matter here. Just trying get people thinking about what it takes to get to this level of performance. I know that it is a little easier to make more HP per cube with smaller engines and I am not adverse to doing that. I think that the basic's are going to be the same for a large or small engine. So the same theory and parts can be used used for most scenario's.


Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

[john marcella]

At 500 cid I think we have the induction capabilities now with several heads. But its still going to take king kong lobe area above .200 to get it done IMO. A build like this is not just heads cam and intake, ITS EVERY THING!

[Chad Speier]

It's all about RPM. You not going to achieve big hp/cid unless you have high RPM.

Just had a customer make 2.50 with a 349, at 9600 rpm.

[Pont428]

Lynn was referring to Pontiacs having real world goals not that we have achieved them. He even contacted Darin to explain his position. He doesnt believe Pontiacs are even close to Pro Stock that is all taken out of context. If you really want to know what he thinks, call him. 317.260.3486 or www.ramairv.com

Tony said a similar conventional head BBC would make 1250HP out of his shop. McCarty Racing got 1219.8 first try, and they are going back for more in a couple of weeks. This thing has incredible midrange and revs like a smaller engine. This is where Pontiacs run good and out do some other engines. Not just peak.

Pontiac guys need to work together to improve not tear each other down.

[RAIV-Z]

Originally Posted by Pont428

Lynn was referring to Pontiacs having real world goals not that we have achieved them. He even contacted Darin to explain his position. He doesnt believe Pontiacs are even close to Pro Stock that is all taken out of context. If you really want to know what he thinks, call him. 317.260.3486 or www.ramairv.com

Tony said a similar conventional head BBC would make 1250HP out of his shop. McCarty Racing got 1219.8 first try, and they are going back for more in a couple of weeks. This thing has incredible midrange and revs like a smaller engine. This is where Pontiacs run good and out do some other engines. Not just peak.

Pontiac guys need to work together to improve not tear each other down.

Stacy,

I’d like to hear some of Lynn’s explanations.

[J.C.you]

Originally Posted by Chad Speier

It's all about RPM. You not going to achieve big hp/cid unless you have high RPM.

Just had a customer make 2.50 with a 349, at 9600 rpm.

what head, intake package?

Keeping the cubes down the visner or warp head could definately be a player in that ballpark with a short decker.

Sportsman short deck Pontiac anyone?

[Transporter]

Originally Posted by J.C.you

what head, intake package?

Keeping the cubes down the visner or warp head could definately be a player in that ballpark with a short decker.

Sportsman short deck Pontiac anyone?

Wasn't someone offering a 9.2 Pontiac block? in aluminum?

That is what you need, hell it would probably bring Marcella back!

[Tom Vaught]

Originally Posted by john marcella

At 500 cid I think we have the induction capabilities now with several heads. But its still going to take king kong lobe area above .200 to get it done IMO. A build like this is not just heads cam and intake, ITS EVERY THING!

Truth

TV

[mike leech]

^^^^^true^^^^^

[dci]

I agree, cam lobes for this level of performance will need to be well thought out and require a stout valve train. Pushrod length will be a challenge for sure.

John what are your thoughts on lifter diameter and a taller lifter? Have you used or know of anyone using 2.0-1 rocker ratio's?



Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

[john marcella]

Originally Posted by dci

I agree, cam lobes for this level of performance will need to be well thought out and require a stout valve train. Pushrod length will be a challenge for sure.

John what are your thoughts on lifter diameter and a taller lifter? Have you used or know of anyone using 2.0-1 rocker ratio's?



Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

Yes , many at 2.0-1 , I am at 1.9. Rocker ratio is your friend and then it becomes your enemy. The valve acceleration is the thing you're after but that's the same thing that can send the system out of control. Spintron is the answer for the seriously trying.

I don't like a tall lifter, it puts more ang in the push rod. .937 key way is the only way to go IMO.

[mike leech]

thats an all in deal. 2-1 rockers. nasty cam lobes, dry sumps, the whole shooting match to get there.

[dci]

Not to mention rotating weight. Things that need attention as well will be piston pin height, ring thickness, ring tension, how far up the piston the ring package will need to be. Crankshaft counter weights, bearing diameters, cam drives. The list is pretty lengthy at this level. That's why I thought it would make a good topic. As things are brought up, I would like to see each one get broken down and analyzed.



Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

[john marcella]

Originally Posted by dci

Not to mention rotating weight. Things that need attention as well will be piston pin height, ring thickness, ring tension, how far up the piston the ring package will need to be. Crankshaft counter weights, bearing diameters, cam drives. The list is pretty lengthy at this level. That's why I thought it would make a good topic. As things are brought up, I would like to see each one get broken down and analyzed.



Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

All that is the easy chit^^^ LOL

[Stan Weiss]

Originally Posted by dci

Not to mention rotating weight. Things that need attention as well will be piston pin height, ring thickness, ring tension, how far up the piston the ring package will need to be. Crankshaft counter weights, bearing diameters, cam drives. The list is pretty lengthy at this level. That's why I thought it would make a good topic. As things are brought up, I would like to see each one get broken down and analyzed.



Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

Don,
Different head designs (like valve incline angle) will each want something a little different. So some empirical always helps. Also VE needed to be used in the CSA calculation. 7000 RPM @ 110 VE will see able the same needs as 7700 RPM @ 100 VE.

Stan

[dci]

Good points!! Pushrods no doubt will need to be 9/16 tapered if there is room.


Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!