Forum: Sprint Car Tech Talk (go)
Moderators: BigDog

Thought i would ask on the tech board since this is somewhat of a tech ques. and this is no trick ques.and maybe no real answer is possible. but here we go.

Since no racing the last several weekends been thinking and was just wondering about this:

Kelly You build 5 identical 360 Flat top piston engines , use the same parts in each right down to the fasteners ,NO VARIATIONS, Machine work done exactly the same way by the same person and all parts that require machining(to make it live-just basic type stuff not a lot of tricks) done the exact same way for each motor and the assembly is done by the same person and each motor is assembled the exact same way , NO VARIATIONS, let say we are using 2 3/16 injectors with all 5 sets of injectors exactly alike , no machine work can be done to the injection system , just bolt it on and say use same pills , nozzles and by passes in each as well as same fuel pump and down to the same size fuel lines and filters .

Now you put all 5 motors on the same dyno one at a time , with each motor getting 15 min. each and say 2 pulls and say that all environmental factors are the same for each motor, room temp. , humiditiy for the room for each session is the exact same and so on (not sure if that is feasable) but what the hell it's just a question. In you opionion how much difference in horses would be in each and say you used 4 Victor Jr. intakes with 4 650 Holley carbs all again exactly the same and no machine work done on anything just bolt it on and put the same jets in the carb and dyno them , would there be more variation of horsepower from the 5 injected motors to the 5 carb motors?

Could possibly all 5 motors be within 5 horses of each other in both injected and carb or is that just impossible.

Again this is no trick question and just may not be a answer either but figure you could give it a shot.

Dayum JD, do I have to work this hard first thing in the morning?  I haven't even took my morning sh*t yet............lol.

We have done back to back to back testing on 3 engines a few times with the above mentioned factors and variables taken into consideration with injected engines.  If my memory serves me right one time they were within a few horsepower of each other.  Now, one other time we did it the engines varied quite a bit, not a ton but enough to make us scratch our heads and wonder why.  We checked and double checked the cam timing, fuel system, and re-calibrated the dyno but to no avail.  There's just those times when no matter what you just can't find a reason!

As far as the carbureted stuff goes we don't do that much.  I can tell you though the one and only time we had 3 carb engines back to back to back was in 1998 when I built mine, Matt Saint, and Brian Plunketts Champ Sprint engines and dynoe'd them consecutively.  They were all identical except for the camshafts which all three were from one end of the spectrum clear to the other end in an attempt to find more torque and horsepower.  Wanna know something?  They were within 5 horsepower of each other!!!  The conclusion we came to was that the 500 cfm carb was the "restrictor plate" and that no matter what we did there was only so much air that carb would let in.

JD, not sure if this answered your question or not but I hope so.  Feel free to ask more!!!

Kelly, I am not one to get in the way of needed neccesities on the ol morning dump but hey you answered my questions , I figured you would know and answered them all and I appreciate it.

I got some other questions , is the restrictor plate the answer to all the so called problems we are having in the Champ Sprint and Super Sprint classes here in OKC as well as in Tulsa , I am sure you know or have heard and all is well documented and talked about on Okla.Tidbits , Is the Restrictor Plate the answer to the Champ Sprints costly motor problems.

Also if you could answer me this , if not I completely understand Cost of an Average motor for you all to build Champ Sprint and cost of a Ground Thumpin Champ Sprint motor? If you cannot answer , No Problem.

From what you wrote in your statement above it sounds to me the restrictor plate might help on bringing the avg. motor more even ,NOT COMPLETELY , but closer to the ground thumper.

Is that a false statement , I understand car and driver play a intergral part in the equation such as a car you all supply power to the # 2 car and KW is fast and motor is nice , but he keeps the car straight and momentum up which keeps the car power band up which is good and lets him win a bunch of races.

What the hell is the answer Restrictor Plate , Crate Motors, Claimers, 305's rules type sprints or is there just not an answer?

Just waitin on that educated answer from up Bixby way .

JD, I have heard a little bit about the restrictor plate deal but to be honest I'm not really up to speed on it.

I think the problem on the Champ Sprint engines started a few years ago when they said that you could run any bottom end you wanted.  I want to know what was wrong with the Crower Sportsman 5.7 rods you could buy for $563.00 a set or the 57lb. Crower Pure stock crank you could get for $900.00?  Now we got guys that have $2000.00 a set Honda rod journal rods, and $2,900.00 lightweight cranks!!  I do like the solid cam and lifters vs. the flat tappett stuff that was a longevity issue.  Why do we have to lighten the blocks?  Yes you take off roughly 14-15 lbs. but if you have us do it for you it'll run you $900.00.  Leave all the factory shit on there!!  Most racers end up bolting weight on anyways to make up for it.  There are a few other areas I'm sure I'm missing, but these come to the front of my mind immediately.

JD, we haven't built a new Champ sprint engine in years.  I think the last one we did were the above ones I mentioned yesterday.  I'm guessing they were about $16,000.

The restrictor plate seems to be the answer everywhere else so I don't know why it wouldn't work there.  I know we did some "plate" testing on the dyno for Kenneth Walker a few years back when he had the OCRS.  He would probably remember more about it than I would, ask him at the track sometime.  Yes a good smooth driver will help out as well.

I really don't know what the answer is JD, I think that will always be a question that can never be answered.................lol. 

P.S.  I am building a brand new 305 for myself and will be putting it in a customers car to run up in Missouri, Iowa, etc. in a couple weeks.  I gave a quote to a guy for $15,000 to do a new 305.  We'll see on the dyno in a week or so how much h.p it makes.

You know Kelly was going to ask if you have done any 305's and well guess one is up in line , yey would like to hear what it does, I agree it's just add more here and a little more there and well it is (motors) where they are now by that method.

Let me ask you this with a compression rule , spring pressure rule and diameter limitation , and a cam lift rule , could you not go back to the flat tappet cams and get longievity out of them then, seems with the roller cams , it adds another 1000 rpm's to the motor which in turn means you better get the best valve train components you can afford which is more $$$.

With those rules could that help on the costs of components and machine work to the components to make them fit to work and to live a while.

Of course does not matter with any rules if no teching is done and well not sure of any answer to that issue.LOL

Kelly , you are answering all these questions with good information,I knew when I thought about asking you , you would give me your take and you have cleared some things up . just might have to meet up with you some where down the road this summer and just buy you a frosty beverage of your choice.

Kind of like hearing from someone in the know that does it everyday and has got some insight on these situations.

JD, yes those are good ideas on the rules but the only feasible one would be a compression rule. The reason? Because it would require very little work and time (about 5 minutes) to check. The other ideas you suggested would be too much to ask of a track to check.

As far as the flat tappett vs. solid cam deal goes here is my simple take. The flat tappett cam if not "broke" in right it can go flat in a heartbeat. Buy a new cam and lifters and start over again. Now say you run one all season, if it was mine which I did have at one time I would put a new cam and lifters in during the winter just to take preventive measures, the flat tappett stuff is pretty cheap. Solid roller cams are a little more pricey BUT I have guys that have been running the same cam for 12 seasons! Granted after the fourth or fifth season we put a new set of lifters in just to be safe. In the end though everybody has their own opinion and that's fine. This 305 I'm building you have to run a flat tappett cam and lifters. I sent my lifters off to get the diamond like coating put on them to help prevent the lifter going flat during break in and for the season, as the commercial goes: set of flat tappett lifters $68.00, diamond like coating to prevent lifters from "flattening" $325.00, not flattening a cam - Priceless..............LOL

So then I guess they do not make a tool that has a gauge on it and you could pull down on the spring and see what the spring pressure reads out on the car at a track ?

Hey I see what you mean on Flat Tappet to Roller, longevity is better , I see what you are saying.

Also can see what you are saying to tech a camshaft at the track without pulling it out of motor.

So is Compression the biggest issue?, you here people talking about Spring Pressures and the beating and stress it does on the valve train which in turn makes the motor turn harder which requires a better bottom end.

OK, with the 2 Bar. motors we run now, is the(legal by the rules) Carb the biggest limiting factor?,lets say you do all you can to a motor and remain legal by the standard 2 Bar. rules say OCRS and then you took the exact same type motor and hog out the heads and did all you could do to it, does the 2 Bar. limit the all out motor to where the motor built within the rules would be close in HP or would it be opposite end of the chart?

Is building a race motor these days without putting it on a dyno or even the new craze now the chassis dyno like going out on a blind date , you know what you would like to have in her ,but your just not sure what your gonna get.

Yeah, they make a gauge for checking spring pressures. That's part of weekly maintenance there.

The compression ratio is a pretty big factor in how much power you can get out of an engine. There's only so much spring pressure you can put on any engine which there are several factors in determining that.

The 2bbl legal heads vs. ported out 2bbl heads with the 500cfm carb would be an interesting test to do. I am just guessing here but I think I would venture to say that the carburetor would still keep both engines pretty damn close in h.p. Again just my guess.

I couldn't imagine not dyno'ing an engine before heading out to the track! I have guys that I get e-mails from and even phone calls that say they don't have their engines dynoe'd for whatever reason. They say it usually takes them about 3-4 races before they get the fuel system dialed in. Why not spend the money ($750) to get it dynoe'd and get that shit figured out before you go to the track? Plus there might be other problems you'll encounter that you could find before the track.

The chassis dyno is pretty popular now a days. It seems like it's more of an "at the track" feeling as to the way the car will respond that we couldn't do on the dyno. We've learned stuff such as headers, mufflers, collector lengths, air cleaner styles and sizes, and other items as to what the car does or doesn't like.

Yey I have one of those Moroso Valve Spring Pressure checkers, gives you a ball park estimate I guess or at least lets you know if you have a really weak or broke spring,check it after every race right before I rerun the valves.

Do you all dyno any motor brought in or is it and inhouse deal for your own motors only, no outside dyno use?

Never had a motor dyno'ed , heard great things about it and like your statement can't imagine running a motor without dynoing it.

JD, we haven't dynoe'd an outside engine for years. If were absolutely slower than shit we'll try to squeeze it in.

Try the chassis dyno. I think the closest one is Wells Racing Engines in Duncanville, Tx.

That is what I figured on outside motors for you all, guess it is time to check into the chassis deal and step up to the plate.

Again Thanks for the answers and advice, it is most appreciated .

JD,

We took our 2-barrel to Wells last week because we were having problems with the fuel system. It was well worth the trip. He picked up 124 HP from the first pull to the last. Besides the fuel problem, it had a problem with the magneto, In fact, it made 42 more HP with the air cleaner on it than it did without an air cleaner.

It looks like we now have plenty of HP. We just have to find a driver!!!!!!!!

So the proverbrial question from me is what did it cost you and how long do you get time wise and did you bring any extra headers,Jets, other Air cleaners etc. to see if anything helped or hurt on different pulls?

What happened the kid quit, Jr. or the Mini Sprint guy or both?

Hurt the motor bad at the last playday on Wednesday night in the injected car or was it something else , looked like the motor from the stands.

Junior is still around. We just need to get him to drive it. I think we have hired a big gun to drive the injected car, when we get it back together. We should have it back together in a couple of weeks. Five hundred for the dyno time. The time is however long it takes. If you go, take all your spares or Dennis will sell you parts.

Can the name of the Big Gun not be revealed?, Curious minds want to know,LOL

I guess you mean by motor parts , Jets , Filters etc.? or am I not getting what your saying.

So the $500 gets you all day or until you top the HP numbers on the dyno or ? .

You are right. We have a Willy's carb, so the jet changing was easy. He put some hotter spark olugs in it. He said the AR51 Autolite's weren't hot enough. He has tires and wheels to use because he will wear out your tires. He puts two 105" ASCS tires and wheels on it. He drills your headers so he can monitor the exhaust temperature. He also monitors the fuel pressure and fuel flow. I think it is the only way to get a 2-barrel set right.

The new driver won't need any instructions on how to drive, he already knows how to race a sprint car. I can't say yet who it is, but he is fast. Notice that I said he, not she. Maybe he can teach Junior how to get around the race track without getting the car upside down.

There you go JD. I honestly believe it is money well spent as Mr. Gosey found out.

Well Kelly and Richard guess it is time to break open the ol piggy bank maybe make a trip down to Dallas.

I wonder if this is the first ever Red Chilly Pepper on the ol Sprint Tech Board. SWEEETTTTTTT!!!!!!!

JD,

For a price, we could tell you which plugs put in your motor, so you don't have to buy them from Dennis.