Speed secret # 5

[jim_howard_pdx]

SPEED SECRET # 5

I first heard about this secret from my friend's dad that campaigned a Dodge Dart with a 426 Hemi. He taught me three things. One: Be in racing for the trophies cause it is the same amount of money and work if you lose, and you have nothing to show for the trouble. Two: Know the rule book better than your competitors, and use every factory racing part to your benefit. Three: The car with the longer rod WINS.

So this is not my speed secret, it has been around since I was in puberty. But I want to discuss it so you can understand its effects on the engine, the cam, the torque, and your et's.

Lets talk about rod length.

Lets look at a small block chevy as an example. 3.5 stroke with a 5.4 inch rod. This nets a 1.54 rod to stroke ratio. Look at my stock 428 engine. It had a 1.78 rod to stroke ratio. This is why my engine can produce 540 hp with a cam similar to the small block chevy's pink cam that made only 375 horsepower. Subtract 540 from 375 and you get 165 horsepower difference. Subtract 428 from 350 and you get 78 cubic inches. So it is not just the cubic inches that made this huge horsepower difference. The chevy has about 390 ft pounds of torque. My 540 hp engine made 616 ft pounds of torque.

See what I am pointing at!!! If you want a boost in torque, increase the rod ratio. On a Bonneville type engine you are after 2.1 or 2.2 rod to stroke ratio.

The engine I worked on for my Buddies Pantara was gunning to be a 200 mph world record car. We ran a 351 W block to take advantage of its .995 higher deck height. Using a 302 crank ground to small block chevy rod journal size, we got the longest rod possible for the engine with custom domed pistons. We hit 224 mph on the first run, and 219 mph on the return run.

Why does a long rod build power and speed?

If you look at the crank shaft as it turns, the piston moves up and down the bore. The length of time it dwells at top dead center is affected by only one thing....ROD LENGTH. The longer the rod, the longer that piston sits there as the flame front burns the fuel, exerting pressure against the piston and combustion chamber giving us our ultra high torque.

The biggest benefit of long rods, is that with tight quench, detonation is dramatically curtailed. So we could run an additional point of compression. This is a win / win situation.

Most important in my mind, is that this extra torque exists at EVERY ignition event. So you get more torque at every rpm range of the engine. Better down low, better in the midrange, and awesome on top. It gives you this without the need for a special camshaft.

So on my next engine, I plan to build a small cubic inch, long rod engine with a Vortec Super charger and water injection. I am going to run high boost, high quench, and high dynamic compression just like I did on that Bonneville engine.

So for all you racers out there in the 11's, 10's, 9's, and faster. Comment on this thread and let everyone know what long rods has meant to your ET's because you cannot get from here to there without torque and the guy with the longest rod WINS.

[Coupe50h]

So thats why my friends 347 kills me j/k

hey man, good material.

although, when say my 302, against buddies lt1(longer rod) he gets raped, then again the 302 revs faster imo, and of course im about 300lbs lighter.

[95mustanggt]

I've read a little bit about this. I read that teh 302 was not as good as the 351, and the 351 was even better than the 428 (?).

That's one of the reasons I'd like to build a stroked 351.

Would it also be fair to say with a longer stroke the exhaust "stuff" gains more momentum on it's way out of the cylinder, therefore decrease dilusion?

[chico]

Jim! Iam looking for advice..Ican't list all my mods, but my signature indicates a little..My third motor running CP pistons, Eagle rods, valve seat and spring work. Running 31 spline moser axels and 4.10 gears.Working on suspension...Am getting ready to install Hamilton Clark Ind.s Cobra intake manifold(guaranteed to give me an extra 60 rwhp on blown motor) I would likee to do the heads but want to keep my car street friendly..what would you recommend for cams , valves, should I port and polish,etc.,etc.???

Thanks in advance Chico

I am running 8.3 comp. and 14 lbs of boost with aftclr.

[jim_howard_pdx]

Thanks for the fun replies.

Coupe 5.0 I think it is great that you dust off your buddies LT1. You have better weight to horsepower, you have a lower first gear with the older T-5, and you have less reciprocating weight.

So keep it up and hope your buddy doesn't read about my secrets...LOL

95 Mustang GT The 302 has a 5.09 rod and a 3 inch stroke for a 1.7 rod to stroke ratio. The 347 stroker has 3.4 inch stroke, and a 5.4 inch rod for a 1.58 rod ratio. The 393 stroker has a 4 inch stroke and a 6.2 inch rod for a 1.55 ratio.

But think of this. Use a 030 over 351 windsor block, run a 3.25 inch stroke, a 6.45 rod and forged piston which yields 329 cubic inches, but maintains a 1.98 ratio. Now run this at 10.7 to 1 compression with no more than .060 combusion chamber to piston dome clearance. YOU MUST KEEP THE QUENCH REAL TIGHT. Mount a Vortec S trim blower with high boost pulley.

Run the stage three trick flow cam with the Trick Flow R head and you should end up with about 750 horsepower, get 18 mpg with fuel injection, and run high 8's or early 9's with 4.30 gears and a Tremec transmission in a 3,000 lb car. You will need a 6 point street roll cage to drag this, plus a helmet, extinguisher, 5 point seat belts and battery cut off.

You will smile like it is no one's business.

Chico, do you have a single or a double overhead cam in that 98?

If running a single cam, SVO makes some heads for it that will boost it to 305 HP. Clean up the ports and make sure the bowl is smoothed and countoured for flow. Do both the intake and exhaust ports, but only the exhaust need any real help. Use a really good header. See if Flow Tech makes one for your application.

Unfortunately cam selection is not what I would like to see for the mod engines. Maybe it is catching up a bit and I just don't know about it yet. Don't worry about dillution on a blown engine, the positive pressure behind the intake charge allows you to run a cam with very little overlap and just use really high lift. Go up to within a .10 to .15 inches of maximum valve lift with your springs. Go short duration and short overlap. Then run the high boost pulley. When I mean short duration, you need about 235 degrees at .050 lift to push 6500 rpm. If you want to hang it at say 8,000 to 8,500 RPM put some money into very light weight pistons and rods, and knife edge the crank. I would seriously consider using the 5.4 liter block for the extra displacement. Then use a 255 to 265 duration cam at very high lift and very low overlap. I think Comp Cams would custom grind a cam for this application.

You can expect about 660 HP if you lighten the pistons and rods, and do some light porting with high lift, low overlap design and the high boost pulley.

Where is pkrwud when I need him, he can tell you the numbers he has seen for these combinations. If you stay with a 4.6 don't expect more than 550 horsepower. You really need the extra stroke to make the torque build on that mod motor.

Wow that was fun.

Now go out and conquer!

[jim_howard_pdx]

Chico, I see now you have the Cobra 4 V engine, by the way that intake is just A W E S O M E. Takes a 14.1 car and makes it a 13.4 car (if you change the gears to 4.10's and run tall slicks. )

Let me know who is cooking up good cams for the Cobra engines and I will do some back door research for you.

Good luck, I love your combo. PUT IN THE 5.4 block with light pistons, light rods, and knife edged crank. You will love 660 HP!!!!

[vetteeatr]

Hey Jim im pretty new to all this engine terminology so could you kinda break it down for me a bit.

And that idea on that 351 is crazy if thats possible and still get that gas mileage i want liek a comepelte blueprint and wher hte heck to get that stuff if oyu have an idea.

Or would those rods have to be custom made?

I assume to get the longer stroke ratio you ground the crankshaft?

Is that it?

A rundown would be great.

And how the heck do you know all this stuff did you go to some school or just kidna been around it for your whole life?

Thanks

[chico]

Jim ! I an allready pulling 515 rwhp...with the new intake manifold I will be at 575 rwhp....ot 676 flywheel HP. I also have a built in advance module , that allows me to advance or retard up to 6 degrees..as long as I am running 100 octane..I carry a case of Torco Fuel Accdelerator ..one 16 oz. can will give me 102 octane to 10 gal. of 91 octane.. this is an additional 40 rwhp.. I understand the right 4 valve heads can give me another 60 to 70 rwhp. I was hoping you wwere up on the dohc motors, if not I believe with your kinowledge and contacts,you can still lead me in the righ direction.

Still getting 21 mpg on cruse control and smooth idle at 800rpms.

Thanks again...I read you posts religiously..


Back in the 60.s I used to have a 55 chevt with a 413 Pont. turning 12.12 and 117 mph..used to play with Scottys Muffler Shop In S.B. Ca. and J and M speed center in Riverside.. Mike Sniveley and I use to street race in SanBernardino every Fri. Nite out on Cajon Blvd....Used to run C Gas..

[chico]

Jim! JUst a quick note and Rer. HCI and their work...They have a 1200 hp Lightning motor sitting on the floor ready for install...Also they built a viper that road races N/A pulling 833 rwhp and 743 rwt....

PS the intake manifold, in case their is an interest..installed for $1100

[Kevin Price]

So for all you racers out there in the 11's, 10's, 9's, and faster. Comment on this thread and let everyone know what long rods has meant to your ET's because you cannot get from here to there without torque and the guy with the longest rod WINS.

N/A I could not be happier. However, my rod ratio and my lower 9.2 deck block height does not give me much room to run an extensive amount of nitrous.

If I had it to do over I would go with a 9.5 deck. But we're talking about longer rods so I have to admit I am pleased with my setup. Sure is nice spanking those big block chevy's.

[chico]

BEAUTIFUL! HOW STREET WORTHY IS THIS MONSTER? This is what I am shooting for...a 9 sec. street car that can still travel to moms house for the weekend. I realize N/A you are probably limited.. most of these posts have no idea what a 9 sec. run feels like...

enjoy this forum....hope you all stay in touch...Jim , please continue with your teachings..Iam passing this on to others.

[chico]

BEAUTIFUL! HOW STREET WORTHY IS THIS MONSTER? This is what I am shooting for...a 9 sec. street car that can still travel to moms house for the weekend. I realize N/A you are probably limited.. most of these posts have no idea what a 9 sec. run feels like...

enjoy this forum....hope you all stay in touch...Jim , please continue with your teachings..Iam passing this on to others.


Do not know what happened , but the server has me doing double..........posts?

[Kevin Price]

My set-up is not that street worthy. Solid roller with some heavy spring pressure, high compression, stall, etc. 9's with a good solid motor set-up and a power adder would be a lot easier to attain than doing it N/A in my opinion.

[jim_howard_pdx]

Chico and Kevin,

Your two cars could not be different.

Look at the ET's Kevin runs now, and where he wants to be. Kevin is looking at the 8's, and i know Eric4Nitrous is looking for mid 7's.

Their cars will be purpose built quarter milers, with light small front tires, and a front suspension designed to allow the car to rise quickly and to transfer the vehicles center of gravity to a rear pivot point. This weight transfer, with proper rear suspension geometry will put the pinion angle square to the gear, put maximum bite on the drag slick, and allow the car to transfer the engines rotational energy into tire rotation with the least loss of torque.

So at a point when you shift your et's from 11 second quarter miles to 10 second ET's, you are deciding that you no longer are going to have a street friendly car, you are going to go for a launch friendly car.

Wait, there are even more changes. The front swaybar goes bye bye, or at least is diminished in size. Front springs are added that work to rapidly push the car vertical with a dampner that allows near unimpeded spring rise (10-30% damping), but very high spring compression valving (70-90%).....you have to smooth out the ride, as the front tires come back to the track surface.

So Kevin's ride is not going to be able to corner like my ride at .96 G's in the corners. And my ride is not going to cut 60 ft times like his 9 second MISSLE.

The engines can be very much the same, after all we put a 2,000 hp merlin rolls royce aircraft engine in a hot rod once. That car did nearly 300 mph at Bonneville, got sold, then later we heard it crashed and killed the driver!

My 9.2 second Mustang was very much a street car, with only suspension add ons and safety equipment like the cage. I could have run an 8 second bracket just by going to a purpose built quarter mile chassis. But we were making lots of money street racing, that paid for all our engineering tweaks.

[jim_howard_pdx]

Kevin was talking about the street worthyness of his engine....What he was alluding to was that he has NASCAR YEATs heads, modified in such a way (I would love to see them) that his engine builds over 800 HP on GAS ONLY.

To do this, he is running very high compression ratios, must use racing fuel, runs exotic oils, and pushes the engine at high rpms to get the HP. So the whole engine is tweaked to d a m n near maximum. The way to go faster now, is chassis improvements, timing and fuel delivery adjustments, and adding NOS.

Kevin, what is your Cubic inches, and what is your bore, stroke and rod length right now?

My ideal street based 9 second car would be this. Use the 351 W block. I think the newer blocks are about .05 inches taller, but the 69 or 70 blocks have the high nickle content. If money is no issue go with a sportsman block with the splayed 4 bolt mains.

Offset grind the crank from a 3.5 inch stroke to a 3.25 stroke, and reduce the jod journal to small block chevy rod bearing size. This reduces the bearing thrust speed, the friction on the bearing, and minimizes bearing failure. I would also use a forged crank for this application since I plan to spin it up to 7,800 rpm or so.....

I would use the TR twisted wedge R heads. I would clean up the goobers, make sure the valve guide supports are teardropped smooth, and CC the ports to make sure they are dead equal for starters. I would stick with the 2.08 1.60 valves since I plan to use a blower.

Use a titanium or aluminim 6.4 inch rod with small block chevy pin and rod dimensions, and 4.03 reduced pin 13/1 domed pistons to produce 332 cubic inches. This nets the 1.98/1 rod ratio in the cheapest possible way. Figure on spending 1 grand for the forged crank, 500 dollars on the machining, 700 dollars on the aluminum rods, and 600.00 on the pistons. (About 2,800 dollars total after you put a grand in the block, or 3,000 for the sportsman unit). Heads are 3,500 set up with racing springs and titanium valves. Intake is 550 but have it extrude honed so count on about 1200. The 88mm throttle, mas, 50 lb injectors, and wiring/computer will be another 1200-2000. Custom fuel curves will be 2,500. So we are talking about a 12,000 to 15,000 dollar engine here.

(I could run a 3" stroke with a 6.625 rod, but this would be a custom rod and custom piston so look to spend about 4 grand MORE than the engine above.) This would be a 306 with a rod ratio of 2.208. This is a perfect bonneville type rod ratio!

Now the cam would be a custom grind, but what I am after is 24 degrees of overlap, 260 degrees intake duration at .050 lift and 280 degrees .050 exhaust duration and .758 lift on the intake and .770 lift on the exhaust. The center line would probably be around 110 degree's, but I am not a grinder, I let them center line the cam, then tell them how important it is to limit the overlap to 24 degrees. (On this type cam you would ordinarily have 75 to 110 degrees of overlap).

I would use the 5.8 Trick Flow EFI with 90 mm inlet, run an 88 mm mas, run 50 lb fuel injectors, and have someone custom burn the algorythems for the fuel curves while the engine was on a dyno mimicking a 5% grade and 800 ft of elevation.

The pistons will be reduced to 11.5 compression by completely smoothing the dome. They will be coated to further reduce head absorption.

If the Vortec S cannot make 750+ horsepower, I would try the Novi 2000. One of them should put me close to 800 hp. The very low overlap would make this car idle like NEAR STOCK. The engine would get acceptable gas mileage until you open the throttle.

You will need a cage to keep the horsepower and torque from twisting the chassis into a pretzel.

You can expect problems with clutches not wanting to maintain bite as the rpm climbs. I think a dual friction, centerforce would be the minimum set up. A full copper/kevlar race clutch like the 7 second cars run might be required.

This would be an excellent engine for 9 second quarter mile times. But Kevin's car would easily beat it drag racing. I would need more cubic inches and better heads to keep up with him.

The 306 would possibly make almost as much horsepower even giving up the 26 cubic inches of displacement, but it is hard to justify the extra 4-5 grand in expense for all the custom stuff just to get the extra two tenths percentage points for the rod ratio. If I remember correctly, I can get a Chrysler 6.4 inch aluminum rod with chevy journals and pins for under a grand. These fit good in the Windsor block with just minor clearancing.

[Kevin Price]

Total ci is 417 with a 4.125 bore, 3.9 stroke on a 6 inch rod. I went with the SVO 9.2 deck block simply because I was getting a run-a-round on the 9.5.

I am running the Chevy journaled rod from Oliver. Please don't tell my chevy friends though, I hear enough from them about the trans.

[jim_howard_pdx]

Those chevy guys are losers.

When we beat them, they always have an excuse and eventually fall back to the..."but you used this chevy part or chevy idea to beat me"...

Powerglides make for awesome and consistent bracket trannies.

LOL, just tell your chevy pals that a well prepared powerglide has NO chevy parts left in it. Nowadays, even the case and control valve are aftermarket pieces.

Man I love your engine... The extra .2 deck height would not really give you enough room for a meaningful road stretch. Your rod to stroke ratio would go from 1.58 to 1.59.

I will share one thing with you Kevin, You should consider running a 3.25 inch stroke with a 6.75 inch rod for a 2.077 rod ratio 329 cubic inch engine.

With your heads and NOS, and the less weight your car can run using the smaller cubic inches, you should be capable of running all the way down to 8.2's or 8.3's.

Just because you don't see a bunch of guys doing this doesn't mean it won't work.

Most speed shops see increased displacement as the way to gain torque, but the strokers end up with these low rod ratio's like yours and then your torque range is short and with a tight peak. Then you have to add weight to the cars to compensate for the higher cubic inches in your brackets.

So a 2.077 rod ratio 329 allows you to build more torque, wider torque, and cut the weight down on your vehicle. This makes for a screaming ride! And a Chevy block will not allow this type of long rod ratio, so you can win your bracket year after year after year.....

Just some food for thought....

I just want to know what Erik4 Nitrous is doing to hit 7.5 ET's. He is going to need a pro-stock chassis to run with this monster. I think he said the engine has dyno'd at 1100 HP. TOO MUCH!!!!....I gotta get one of these.....

[Eric4Nitrous]

I plan on running mid to high 6's not 7's.lol I've already been in the 7's My new car is going to be a pro-stock style car. Motor dyno'd at 1780+hp on three stages.

[ultraflo]

Rod/Stroke ratio is a highly debated topic... some believe that rod/stroke ratios are meaningless when it comes to total power output/potential. I tend to keep an open mind on the subject, but when I first read about running a longer rod, it made sense... more dwell at TDC for a more complete burn. There was a good thread on this over at hardcore50.com some time ago...

FWIW, I used a 5.400 (1.8:1) rod in the stock block'd 306 I ran this year. Going to run the same rod length in the R-block 306 also.

I'll be happy with around 750hp to the wheels... for awhile anyhow. Not sure I'd know what to do with a setup that approaches 2000hp... soil my draws, prolly.

[jim_howard_pdx]

Eric I wish you good luck, but like the honda engine crowd, I tell them yes you can have 600 hp but for how many runs.....

Running 6's would be a much easier job for a big block and NOS. Bigger stronger parts, bigger stronger crank, bigger beefier mains and blocks.....

You are putting that poor small block on the absolute edge of its envelope. Or is this a 460 based engine you are working on for the 6's?

I expect it to take you a while to dial this set up. What transmission will you be using?

If the parachute doesn't deploy, how do you plan to stop the thing?

Man, my mind is swimming with all the stuff it takes just to drive 7's safely.....

You go....rocket man Eric 4 Nitrous!