[dci]

That's cool!! I think the new technology is awesome. I just did not want anybody getting all wigged out LOL.



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 !!!!!

[455-4+1]

A little off topic (well engine wise anyway, I do realize it says Pontiac) but just for ****s and giggles, my sons junior dragster makes 46HP from 15.2559 CID LOL (250cc) so smaller must be easier LOL

This comes out at 3.01 using factory ratings for the engine

TQ peak is at 10,500 and peak power at 15,500, factory redline at 18,000
Its a 4 cyl, 4 stroke with 4x 25mm Kehien carbs on 96 octane pump gas.

Not related I know, but sometimes I think you need to look at extremes to make sure you are not clouding yourself with what you think is a limiting factor, I know I have been guilty of this in the past myself. Obviously Pro Stock is the place to look in this thread for more conventional layouts, ie pushrod if you could call their stuff conventional LOL.

I know the thread stated a cylinder head available now, and I realise the logistics and possible suicide mission it would take financially, but would an OHV deal make this easier in the future ??

Back to topic, seriously interested in short block discussions relating to deck height, rotating assy parameters and bay to bay windage discussions if anyone is willing to spill the beans
(as long as its not proprietary information that pertains directly to their business as mentioned)

[Stan Weiss]

Originally Posted by john marcella

A friend that run PS bike and after spintron testing has told me that the port needs to cater to the push rod, Make room! But then again he runs a 2.700+ valve at 9800 so because of weight and valve acceleration ,he has big spring press, you may not need that kind of press. There are many variables.

Just for reference I am at 284@50 206@200 .543 lobe 1.9 rocker and total weight of valve, retainers , locks and lash cap is 119g. I am stable through 9200 no prob. IMO you will need to get more like 210+ at .200 with a 1.9-1 and better yet 2.0-1. That im sure would be enough area to insure you could make the 2.3 with a Pontiac with that kind of area. JMO I could wrong.

John,
I believe George Bryce as of the end '13 was running 2.7" with a .600" lobe with 2.0:1 rockers intake and 2.0" with a .600" lobe with 1.85:1 rockers exhaust. But remember that they are 2 cylinders and if it was a v8 it would be around 640 ci, yet they turn over 10,000 RPM. Note they are running a 5.1xx" bore. Since last fall George PMed me the HP and torque, lets just say it is over 2.3 HP per and under 2.4 HP per.

Stan

[Scott Roberts]

I believe 2.5 is attainable with the right combo...that would NOT include a 10.24 deck height. .

[Half-Inch Stud]

Originally Posted by 455-4+1

A little off topic (well engine wise anyway, I do realize it says Pontiac) but just for ****s and giggles, my sons junior dragster makes 46HP from 15.2559 CID LOL (250cc) so smaller must be easier LOL. This comes out at 3.01 using factory ratings for the engine. TQ peak is at 10,500 and peak power at 15,500, factory redline at 18,000
Its a 4 cyl, 4 stroke with 4x 25mm Kehien carbs on 96 octane pump gas.

Curious What engine is that?

We're developing a 450cc (22.5 CID) 2-Stroke; Carb'd been making over 55HP at 6000, probably more at 6700. Goes to 8000 if we let it. Think it was93 Octane but not so sure.

fuel-injection is suppose to help the SMALL engines make more power, so we're looking forward to that.

[john marcella]

Originally Posted by Stan Weiss

John,
I believe George Bryce as of the end '13 was running 2.7" with a .600" lobe with 2.0:1 rockers intake and 2.0" with a .600" lobe with 1.85:1 rockers exhaust. But remember that they are 2 cylinders and if it was a v8 it would be around 640 ci, yet they turn over 10,000 RPM. Note they are running a 5.1xx" bore. Since last fall George PMed me the HP and torque, lets just say it is over 2.3 HP per and under 2.4 HP per.

Stan

Trust me Stan, I know every last thing about George's cyl heads.

[BruceWilkie]

Originally Posted by Scott Roberts

I believe 2.5 is attainable with the right combo...that would NOT include a 10.24 deck height. .

Agree with that... 9.15- 9.5 deck better suited as it allows much lighter recip pieces. Smaller mains mat not be mandatory but would help. I think lifter bore angles/ positioning and rocker position have to compliment each other. Multiple angle pushrod travel aint going to cut it. Pushrods could end up longer than you'd think with a short deck but not likely as long as a 10.2 deck... IMO rocker fulcrum point raised would help decrease angles seen thru the arc as would a lifter bore angle that compliments the valve/rocker layout.

As far as heads... I cant disagree that there are a few we already have that are candidates to top this motor.

[dci]

How much effect does a merge collector as opposed to a try-y header have on the power curve? Anyone have any experience with that?





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 !!!!!

[BruceWilkie]

Originally Posted by Half-Inch Stud

Curious What engine is that?

We're developing a 450cc (22.5 CID) 2-Stroke; Carb'd been making over 55HP at 6000, probably more at 6700. Goes to 8000 if we let it. Think it was93 Octane but not so sure.

fuel-injection is suppose to help the SMALL engines make more power, so we're looking forward to that.

You are way off original topic HIS but... modified 485 fan(twin 2 stroke) on 93 made 93hp at 7800 originally 89 octane 56 hp at 7200 same 38 mm carbs... 493 liquid with smaller carbs(36's?) made about the same at 92 hp but was stock, 89 octane factory tune, about 7800 rpm peak power. Both piston port reed valve design... competitors case reed 500(499) was over 100 hp(105 iirc) on 89 octane gas with 38mm carbs but closer to 8500 rpm power peak.
Not bad for @ 30 ci motors, 2 of which came with warranty. Both liquids docile enough for novice users. Fan was at its thermal limitations... just couldnt cool spark plug(10 series NGK) long enough to stay out of trouble pushing more power thru it.

Find a way to seal up a Pontiac and mods needed to make it a 2 stroke reed valve motor and 3 hp per ci NA should be doable.

[65nss4spdGTO]

So back to the original target here of 1150 HP.

The biggest bore size is 4.400", the stroke is 4.114".

What is the peak RPM?

Calvin Hill
Hill Performance
708-250-7420

[john marcella]

Originally Posted by 65nss4spdGTO

So back to the original target here of 1150 HP.

The biggest bore size is 4.400", the stroke is 4.114".

What is the peak RPM?

Calvin Hill
Hill Performance
708-250-7420

Why is the biggest bore 4.400? Who says

[john marcella]

Originally Posted by dci

How much effect does a merge collector as opposed to a try-y header have on the power curve? Anyone have any experience with that?





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 !!!!!

Just like with anything else its chit you got to test and test multiple variations to find what works the best.


I personally have only ever had Try Y on my car that I made, and the reason for that is because they fit in the car really good. Now I will no longer be running a Try Y , probably ever.

[Half-Inch Stud]

Bruce, thanks for sharing your perf data. Enough about 2-strokes huh.

[BruceWilkie]

Originally Posted by 65nss4spdGTO

So back to the original target here of 1150 HP.

The biggest bore size is 4.400", the stroke is 4.114".

What is the peak RPM?

Calvin Hill
Hill Performance
708-250-7420

VE will dictate rpm but I think somewhere between 9200 and 9800 rpm 2.3 could be done.

For gasket consideration I'd go a tid smaller on bore(4.375) and use 4.15 stroke for a 499 displacement . I think a 3.75 stroke short deck at 451 would make 2.3 or better easier... (2.549 per ci at 451 to 1150 hp would be a real stretch unless you hit powerball)

[slowbird]

Originally Posted by BruceWilkie

VE will dictate rpm but I think somewhere between 9200 and 9800 rpm 2.3 could be done.

For gasket consideration I'd go a tid smaller on bore(4.375) and use 4.15 stroke for a 499 displacement . I think a 3.75 stroke short deck at 451 would make 2.3 or better easier... (2.549 per ci at 451 to 1150 hp would be a real stretch unless you hit powerball)

Really dont think it'd take that much rpm.

[john marcella]

Originally Posted by slowbird

Really dont think it'd take that much rpm.

Agreed

[65nss4spdGTO]

With the bore and stroke I listed, an RPM range of 8500 to 8700 would be the target.

The VE should be enough at the piston speed to make the projected power with a cylinder head that flows 475 CFM to 495 CFM.

John, where did your build make peak power?

Calvin Hill
Hill Performance
708-250-7420

[Scott Roberts]

Where would u put the range on s 451 with 450cfm.heads

[BruceWilkie]

Originally Posted by slowbird

Really dont think it'd take that much rpm.

You are likely correct, I guesstimated VE and bsfc a tid on the conservative side... Stroke choice makes a difference... 4.375 bore 451 or 499 combo is going to be different rpm ranges with same heads though the smaller motor does have better VE potential.

[65nss4spdGTO]

Originally Posted by BruceWilkie

VE will dictate rpm but I think somewhere between 9200 and 9800 rpm 2.3 could be done.

For gasket consideration I'd go a tid smaller on bore(4.375) and use 4.15 stroke for a 499 displacement . I think a 3.75 stroke short deck at 451 would make 2.3 or better easier... (2.549 per ci at 451 to 1150 hp would be a real stretch unless you hit powerball)

Honestly I don't see any standard deck height 500ci Pontiac engine making that level of power with a longer stroke. As John has stated, the bore has to be as big as you can make it. That's the only way you can put enough valve in the engine to support the airflow demand. For inline valves with a stroke around 4.000", shortening the deck height .800" would allow shorter pushrods, add a 60MM cam and now the length of the push rod can be greatly reduced, but the shorter the deck height, the more stress will be created when an offset valve train is required.

Calvin Hill
Hill Performance
708-250-7420