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Author Topic:   anyone ever Dyno their mod engine?
BrianW
Dirt Freak

Total posts: 385
posted December 09, 2002 03:36 PM  
I am planning on running a modified next year and have been thinking about different engine combos - and of course the cost to achieve the power levels that most guys say they have or say is needed to race competatively.

My question is this - has anyone ever dynoed their engine, and if so what were the results and how competative do you think the engine is???

I know it takes chassis setup to get the power to the ground, but I can't afford to build an engine twice I hear guys say 500, 600, 650 hp++ and don't know what to believe - I also read the engine cost comparison and I'm more confused! I ran a couple of engine combos of mods that I'm looking at through "Desktop Dyno" and got huge differences in what is being quoted and what comes up - and the numbers some provided were supposedly from reputable engine builders.... I've only personally dynoed 1 coombo and it's close (DD was high) so I can't believe that it's that far off!

If it makes any difference I am planning to run Lakeside Speedway in Kansas City, KS.

Wauge28
Dirt Freak

Total posts: 262
posted December 09, 2002 05:38 PM  
Hp is sooo over stated. Most people that say they have 600 HP more than likely have 500Hp. Desk top dyno is junk. Sorry to hurt feelings out there but that is the plain truth.

I am very fortunate to have a great motor builder as a sponsor and he does have a Dyno. I have a very strong 383 back up motor with roller cam, good rods, piston and steel crank. 208 heads and all the good stuff. In most peoples opinion, this is a 600 hp motor. I have loaned it out to people and they come back with big grins on there face and love it. In reality, it is a 510 HP motor...when it's fresh. I have a 421 with even better stuff in it including Aluminum Pro Action heads. This baby has it all. The galley of the block is polished and looks like chrome ( I know that doesn't make HP but it can show how much time this thing has in it). A Crower Roller with 815 Lift, huge flow numbers on the heads and you would think 650 to 675 HP...??? How about 595. We have used a light ring package and even a vacumm pump with 15 weight oil. Special oil pan to reduce the oil slap and still...595 HP.

The point to all of this is...don't let people Bull$h)t you. 500 ponies are alot and in most cases plenty.

O.K., let the bashing begin. I can take it

outlawstock17
Dirt Forum Champ
Total posts: 1363
posted December 09, 2002 05:57 PM  
no bashing from me wauge28. i agree totally. desktop dyno is good for making comparisons, but not for figuring actual HP numbers. it really doesn't matter how many ponies you have anyway. it's how quick you can turn a lap that matters.

it's very difficult to lay down a good lap in an over powered car. it's like trying to use nitrous oxide on a dryslick.....

Bumper
Dirt Forum Racer

Total posts: 83
posted December 09, 2002 06:26 PM  
Our motor builder dyno's every motor we have built. The biggest thing we have found is all the people who talk about these 15 and 16 to 1 motors are full of it. We mainly dyno our motors to find out what combinations make what, and how high I can rev it still making some hp. As far as how much we make, I'll never tell!

dirtracer14
Dirt Forum Champ
Total posts: 1261
posted December 09, 2002 06:29 PM  
Well mark i dont feel so bad running my cast 400 to 425 hp motors against you guys I have seen dyno sheets from some of the mod motors around here and they are in 575 to 625 hp range. Most of these are 406 or bigger cola crank full roller and most of the time they are in dart blocks.They put alot of $$ into these motors for what they say is to make sure they stay together. I have never put mine on the dyno so i have no idea what im making....

Bumper
Dirt Forum Racer

Total posts: 83
posted December 09, 2002 06:46 PM  
I will say this, my favorite is a 360. Just enough power for the heavy heat race, and not to much for a super dry main. If you run in an area where the tracks go dry, build a motor that will last, and has even power. To much will make you go backwards.

dmdracer
Dirt Roller

Total posts: 12
posted December 09, 2002 07:15 PM  
I have a 393 ci that was built in Texas by Race engine service in april 1992, they built alot of Cosworth engines for the Indy cars back then. it has all the good stuff... callies, je, lentz. steel heads, 2.08's have been ported and polished, tubes, etc. I have the dyno sheet in front of me and it says hp:622.6 @ 7500 rpm...trq: 518.9 @5750. this is on a c&s 700 alky carb. I've been very happy with this Eng. plenty of power, almost too much when track dries out, you really have to be patient with the throttle. I really believe around 500 hp and a good handling car is sufficient unless your running an Eldora or Terre Haute. hope this helps.

HONDO
Dirt Full Roller

Total posts: 47
posted December 09, 2002 07:21 PM  
Your right, horsepower isn't everything. We dynoed 490hp and 550lbs torque. 2002 was our first year in mods and that was plenty on most nights. I need to handle better way before I need more power. We dyno more to make sure we aren't missing something with timing, jetting, or carb spacers. We don't wan't to throw away power by doing something stupid. Dyno is right next to track so its convenient to tune there. I would say a minimum target would be 450hp, although you can get away with less on a lot of nights. I say Wauge28 is right on the money.

Greggie
Dirt Freak

Total posts: 298
posted December 09, 2002 07:40 PM  
My motor that I took to the SuperNationals went 590 horse on the dyno and I could have used another 50 or so. We ran one on the computer at the beginning of the year and it went 628. It exploded at Eldon in a heat race. That motor was the best I have ever slapped together, and my car really liked it. Too bad I had to use cheap parts or it would still be alive today.

If you run a lot on tacky tracks, you need a hawg, but the long-stroke motors aren't very user friendly when it slicks off. The best dry-slick motor I ever drove was a 355 with 617 hypereutectic pistons and sportsman II heads.

Greggie

BrianW
Dirt Freak

Total posts: 385
posted December 09, 2002 08:55 PM  
Interesting reading so far...

Anyone ever dyno their stock headed 355? I've got one that came out of a street stock that I'm planning to use as a backup engine.

HRT187
Dirt Freak

Total posts: 265
posted December 10, 2002 12:17 AM  
Anyone ever find horsepower on the dyno with jetting, power valves, acc nozzle size, acc pump cams, etc?

tilley88
Dirt Forum Champ
Total posts: 879
posted December 10, 2002 12:47 AM  
I don't care what class you run, Hp is in your right foot!

BrianW
Dirt Freak

Total posts: 385
posted December 10, 2002 10:34 AM  
quote:
Originally posted by HRT187:
Anyone ever find horsepower on the dyno with jetting, power valves, acc nozzle size, acc pump cams, etc?

On street engine's I can say a LOT of power is found by tuning on the dyno. on a mild 300 hp engine I've found an extra 20-25 Hp in timing, jetting & carb changes. That's 6-8% and I'd have to say on a race engine you might be able to pick up 5% or more if it's poorly tuned!

If you've got a good dyno operator that will help with advice the hour's worth of dyno time can be the cheapest "performance part" $/hp wise...

Pa FastBoys
unregistered Total posts: 385
posted December 10, 2002 12:16 PM           send a private message to BrianW   Edit/Delete Message   Reply w/QuoteBBBBBB
We have our motors put on the dyno at the engine builders shop and we have a 355 with flat top pistons at 515 HP and a 415 at 640 HP.

JasonBrock
unregistered Total posts: 385
posted December 10, 2002 02:15 PM           send a private message to BrianW   Edit/Delete Message   Reply w/QuoteBBBBBB
That flat top 355 must be an SB2 or something??

24mod
Dirt Full Roller

Total posts: 31
posted December 10, 2002 03:27 PM  
My motor builder just built a 355 flat top solid lift with Vortec Heads that made 506 at 6800, which worked perfect for a dry slick track. Also have a 400 block with a 350 crank (makes a 377), roller cam and dart heads that made 539 at 7000. The differnce on a dry slick track is like night and day between these motors and the ease of getting them to hook up. So my opinion, stay with something around 500 on a dry slick with good reliable parts, and the sky is the limit on a hard hooked up track.

HONDO
Dirt Full Roller

Total posts: 47
posted December 10, 2002 07:07 PM  
How bought some torque numbers guys? Getting off the corner is what we all shoot for, right?

Dirt Track Junkie
Dirt Roller

Total posts: 15
posted December 12, 2002 04:46 PM  
We had our motor dynoed at 545hp and 497ft lbs torque. Then with a push of a couple keys on the key board it made 570hp and 510tq. I had a guy show me a sheet that showed an engine making 675hp and 560tq and he said his chassis could bog the motor it hooked so good. Yes this was a modified too. He never beat me because of motor, handling I'd say yes. So I'd say dyno to find good timing and fuel settings and then take it to the track, get you car handling good and drive the s**t out of it.

It always sounds simple here on the message board.

[This message has been edited by Dirt Track Junkie (edited December 12, 2002).]

Wauge28
Dirt Freak

Total posts: 262
posted December 12, 2002 07:02 PM  
I am surprised no one has said this yet... Dyno readings are only as true as the operator is honest. There are so many adjustments that give very inflated numbers. I don't know of any real way to make sure your numbers are real except to...have two different people dyno and build your motor. In other words, a builder who dynos his own motors is more likely to play with the altitude and other settings....hhhhmmmmm. "Man, that guy builds killer motors...look at this dyno sheet." Yeah...right.

jlfastride
Dirt Maniac

Total posts: 135
posted December 12, 2002 09:58 PM  
anyone ever dyno a 406 13-1 with roller and pro 1 230 cc heads?

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted December 12, 2002 10:15 PM  
I agree with Wauge that dyno numbers can be skewed based on the operator. Another thing is how well is the dyno itself calibrated. When we dynoed our motor last year it came up short of what we thought it should be. Then they told us that their dyno was reading about 5-7% lower than others in the area. Meaning some guys who had dynoed the same motor both places got different numbers. So you have to take dyno numbers with a grain of salt. In our case we picked up about 10HP with timing and jetting and that is an increase in HP no matter what dyno you run it on whether it is 100% accurate or not. After all thats what we dynoed for anyway was to make improvements not to have numbers to brag about.

I have a hard time beleiving some of these guys need or use all of 650 hp in a modified on hard tires especially when it goes dry and slick. Last year i know alot of guys were trying to detune their motors to cut back on power to hook up better and they werent making 600hp to start with.


Dirt Track Junkie
Dirt Roller

Total posts: 15
posted December 13, 2002 12:57 AM  
Last year I had to run a different motor than we usually do. It was .300 shorter on stroke, .375 shorter on rod length and a stock head with a "nothing fancy" port job. It has never seen a dyno. The car was more drivable and I didn't have to back pedal as much when the track started to dry out. I'm curious what kind of numbers it would make, but.......... it doesn't really matter now that I think about it.

75xracer
Dirt Full Roller

Total posts: 41
posted December 13, 2002 09:15 AM  
There is a way to tell if a dyno has been "jacked up". Does anyone have a dyno sheet in front of them? Look at the horsepower and torque at 5250 rpm. What are the readings? If it's a good dyno, with an honest operator, the readings will be the same. Yea, that sounds crazy, but look at the readings from a good sheet, and you will see that it's true.

BrianW
Dirt Freak

Total posts: 385
posted December 13, 2002 09:25 AM  
quote:
Originally posted by 75xracer:
There is a way to tell if a dyno has been "jacked up". Does anyone have a dyno sheet in front of them? Look at the horsepower and torque at 5250 rpm. What are the readings? If it's a good dyno, with an honest operator, the readings will be the same. Yea, that sounds crazy, but look at the readings from a good sheet, and you will see that it's true.

All dynos that I know of measure only torque and calculate HP from the measured value of torque. So no matter what the operator puts in as correction values the #'s will cross as it's a mathmetical calculation.

The ways to jack with dyno numbers are to put in higher than ambient temps, lower barometric pressure, etc. Also adjusting the torque absorption values - on a inertia dyno that's simply moving the value of the weight of the roller - say the roller weighs exactly 2000 lbs - if the operator puts in that it weighs 2200 lbs that's an instant 10% since the calculations will be thinking you're accelerating more weight - and curves will cross exactly at 5250...

I would never take an engine builder's dyno numbers seriously - it's like dirtbuster said - use it as a tuning tool and use it to compare before / after changes and use it as a tool to find more HP in the combo you've got.

75xracer
Dirt Full Roller

Total posts: 41
posted December 13, 2002 02:40 PM  
Brian- Since I'm not a dyno operator myself, I can't argue, but I was told that by a reputable engine builder. I've seen sheets from several dynos, most of which had the torque and hp cross at 5250, but I have also seen sheets with unbelievable numbers that did not have the curves match at 5250. If what you are saying is true, then how would you explain this?

outlawstock17
Dirt Forum Champ
Total posts: 1363
posted December 13, 2002 03:12 PM  
brian already explained it. torque is the quantity measured by the dyno and horsepower is figured by that value. like he said, horsepower is figured by a mathematical calculation. the equation dictates that horsepower and torque are equal at 5252 rpm.

HRT187
Dirt Freak

Total posts: 265
posted December 13, 2002 03:20 PM  
quote:
Originally posted by Wauge28:
I am surprised no one has said this yet... Dyno readings are only as true as the operator is honest. There are so many adjustments that give very inflated numbers. I don't know of any real way to make sure your numbers are real except to...have two different people dyno and build your motor. In other words, a builder who dynos his own motors is more likely to play with the altitude and other settings....hhhhmmmmm. "Man, that guy builds killer motors...look at this dyno sheet." Yeah...right.

No doubt, but the tool shouldn't be used for throwing numbers around at the bar, it should be used to figure timing and fuel just like a few have already said.

If you get a dyno that has a wide band O2 sensor you can learn a lot. I've done this with a few street cars. I've always wondered if there are rich or lean spots in my fuel curve though, and to me checking plugs is only so accurate with any ignition that throws a decent spark.

75xracer
Dirt Full Roller

Total posts: 41
posted December 13, 2002 03:27 PM  
Maybe I misunderstood, but it sounds like he is saying that hp and torque will always cross at 5250 nomatter what info is put into the dyno. I've seen sheets that disagree with that. That is what I'm asking him to explain.

BrianW
Dirt Freak

Total posts: 385
posted December 13, 2002 04:03 PM  
quote:
Originally posted by 75xracer:
Maybe I misunderstood, but it sounds like he is saying that hp and torque will always cross at 5250 nomatter what info is put into the dyno. I've seen sheets that disagree with that. That is what I'm asking him to explain.

Well, honestly I can't explain it - the "easy" values to jack with are the ones that will not interfere with the calculation -

Horsepower = (Torque * RPM) / 5252

Given that - when RPM=5252 then the two will cancel each other out and HP will be equal to TQ. The only way to jack the HP numbers is to interfere with the 5252 variable.

Another way to increase HP is the RPM variable (i.e. select 6 cyl in the dyno, and when 8 sparks occur that's 8/6th exaggerated or 1 1/3 the true RPM - at 1000 RPM the dyno will be reading 1300, at 5000 it will read 6666 RPM - but in this case they'll still cross at 5250..

If the operator wanted to he can go in and edit the raw data and reproduce the graph... or just export it to something like EXCEL and add 15% to the HP and re-graph not re-calcualting the TQ numbers...

I'd like to see the graphs and do the math back and forth - you'll probably find the difference right there (use the HP, calc TQ and use the TQ numbers to calculate HP... Excel would be real easy for this one)

superdave
Dirt Freak

Total posts: 280
posted December 14, 2002 11:50 AM  
To me the best thing about dyno time would be getting the tuning right so the motor would last and run it's best. Numbers are easy to hit nowadays with bolt on parts. getting the tune up right so you run the right gear where the power is and not burning a piston the first night would be important to me.

I would have a motor dynoed before you pay for it. If it come apart on the dyno at least it isn't my motor yet.

75xracer
Dirt Full Roller

Total posts: 41
posted December 14, 2002 04:53 PM  
Thanks for the reply Brian. Sounds like you know your Dyno. Quote, "The only way to jack the HP numbers is to interfere with the 5252 variable." That's all I was saying, basically. If you have a dyno sheet that has hosepower and torque not matching at 5250, then the dyno has probably been jacked up in one way or another to show alot of horsepower. I'm sure some engine builders try this to sell engines. Horsepower sells!

dmdracer
Dirt Roller

Total posts: 12
posted December 14, 2002 06:43 PM  
I dug out my "sheet" and at 5250... trq is 516.6 hp is 516.4.... there is some dif. not sure which way or why. just more food for thought...

BrianW
Dirt Freak

Total posts: 385
posted December 15, 2002 10:12 AM  
quote:
Originally posted by 75xracer:
Thanks for the reply Brian. Sounds like you know your Dyno. Quote, "The only way to jack the HP numbers is to interfere with the 5252 variable." That's all I was saying, basically. If you have a dyno sheet that has hosepower and torque not matching at 5252, then the dyno has probably been jacked up in one way or another to show alot of horsepower. I'm sure some engine builders try this to sell engines. Horsepower sells!

Let me clarify this - the only way yo jack up the HP numbers so that the HP & TQ values don't cross at 5252 is to jack the 5252 constant. There are PLENTY of other ways to increase the HP readings on a dyno that are MUCH easier.

Another way I can think of is plain 'ol manual doctoring of the readings - changing the readings in the result files to whatever numbers the operator wants to show...

- Brian

Woody44
Dirt Full Roller

Total posts: 53
posted December 18, 2002 01:12 PM  
quote:
Originally posted by BrianW:
I am planning on running a modified next year and have been thinking about different engine combos - and of course the cost to achieve the power levels that most guys say they have or say is needed to race competatively.

My question is this - has anyone ever dynoed their engine, and if so what were the results and how competative do you think the engine is???

I know it takes chassis setup to get the power to the ground, but I can't afford to build an engine twice I hear guys say 500, 600, 650 hp++ and don't know what to believe - I also read the engine cost comparison and I'm more confused! I ran a couple of engine combos of mods that I'm looking at through "Desktop Dyno" and got huge differences in what is being quoted and what comes up - and the numbers some provided were supposedly from reputable engine builders.... I've only personally dynoed 1 coombo and it's close (DD was high) so I can't believe that it's that far off!

If it makes any difference I am planning to run Lakeside Speedway in Kansas City, KS.


I'm definately no motor man, and i hate to spend money, but Lakeside is an exception. You have to have decent horses, but you definately need good stuff, lakeside is hard on engines.
My personal experience is that if your gonna run with Tom Charles, Tim Karrick, Pippert, etc.. you are gonna need some serious horsepower, and be as hooked up as possible. We never did this
Between CMS and lakeside the competition doesn't get much tougher.

AJ Wood
Fawksy Lady Racing

dode
Dirt Forum Champ
Total posts: 613
posted December 20, 2002 10:29 AM  
I know that this is an old topic, but does anyone have an estimate as to how much HP you lose through the drivetrain? I dyno'd my car a couple of weeks ago so that I could see how the rear suspension was moving (I'm new to all of this) but then got curious about the HP/Tq numbers. I've got a Brinn tranny...

Any estimates?

Thanks!

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted April 20, 2005 01:58 PM  
Through a Brinn and 9" Ford setup I beleive you lose about 15-18%.

Mastersbilt05
Dirt Roller

Total posts: 21
posted April 20, 2005 10:43 PM  
We have all of our motors built and then sent straight to the dyno. We have a 360 c.i. Vortec that makes 572 hp and 530 ft. lbs. of torque. I have been to several tracks where I have needed more. We also have a aluminum headed SB2.2 406 that dynoed 781 hp at 678 ft. lbs. which we have run in our modified. These numbers come from a very reputable engine builder that purchased his dyno from D.E.I. where one of his friends builds engines. We are very good friends with him so I have a hard time believing that he is lying.

Kromulous
Dirt Forum Champ
Total posts: 796
posted April 21, 2005 07:57 AM  
That SB2.2 very smooth in a Mod?

781 hp, is a ton for a Mod, but i have been hearing of them trickling in Mods lately, SB2.2 Engines that is.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted April 21, 2005 08:03 AM  
A lot of the top USMTS are prob pushing 650-700. Like mentioned above at Lakeside I swear if you dont have about 650HP you dont really have a chance, and thats weekly. That track is always hooked up and always fast and not only do you need lots of power you have to make it last. It spretty much wide open all the way around. Thats an exception though, most of the time any other track, 550-600 I would say is plenty on the hard tire and slick tracks.

[This message has been edited by dirtbuster (edited April 21, 2005).]

Ego Racing
Dirt Forum Champ
Total posts: 724
posted April 21, 2005 09:43 AM  
We ran a 785hp small block motor in a modified on asphalt and it was almost miserable. At USA Speedway 5/8 mile asphault I coould put the car sideways at the flag stand and we were running gearing in the 3's. A sponser run drag and off shore boats and we got an engine from him when he blew one. We also tried a 760ci 1100hp motor and there was no way to drive the car. We tried with a friend who has run and won MANY Hooters cup races and he had the same opinion. We are now running a crate motor in a late model on dirt and at our local track we are running with $30,000 362ci alcky motors and we can run right with them. Last year we ran a 580hp alcky motor and I think the crate motor is smoother and easier to drive and our times have not changed.

zeroracing
Dirt Forum Champ
Total posts: 1875
posted April 21, 2005 09:51 AM  
Lakeside will take over 600 to power around it most all the time. that track is big and heavy 99% of the time.

Mastersbilt05
Dirt Roller

Total posts: 21
posted April 21, 2005 11:48 PM  
That SB2 is actually just as drivable in a mod as anything else that I've driven. We race on a super slick flat 1/4 mile and it doesnt bother me. We run top 5 almost every weekend at all of the tracks around here. It all depends on the way its built and if you have a heavy foot or not. Dont get me wrong, it will blow the tires off at any time on any track I have ever been on. There are some motors that I have driven for other people that dont have but between 5 and 600 that are really really erratic and dont have a smooth power curve. Its just whether you build a motor to go down a drag strip or oval track, they are all built different and 600 horsepower is sometimes not just 600 horsepower and thats it. Alot of people dont understand that.

Kromulous
Dirt Forum Champ
Total posts: 796
posted April 22, 2005 07:29 AM  
Thanks Mastersbuilt, i'm justing researching SB2.2 stuff, and looking for real world input on how they run.

Mastersbilt05
Dirt Roller

Total posts: 21
posted April 22, 2005 10:53 AM  
Your welcome, if you are thinking about building an SB2.2 then just watch ebay. We bout every part for both of our SB2's on ebay. Our first SB2.2 was a alum. headed 406 with Hendricks heads. This is the one that I was telling you about. Whenever the NASCAR guys run the motor once they sell most of the parts on ebay or to other dealers. Those heads had like 200 laps on them at Michigan International Speedway. Our 2nd one was a all alum. 421 it has D.E.I. heads and it made 828 hp and 685 lb ft. of torque. We have also built those Ford SVO motors which are also real good. Its pretty much just preference. I am a chevy man so you see what Im saying. That Ford was a 358 and it mad 760 hp. ANyways you can find most of your stuff on ebay or 4m or from JR motorsports.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted April 22, 2005 12:37 PM  
Mastersbilt 05,

If you dont mind my asking, even getting all that stuff off ebay or whatver, what did it cost to put together one of those engines. If you dont want to say thats fine, I understand completely. Just seems to me that it would be pricey for a mod, for a late model maybe not out of line though.

Mastersbilt05
Dirt Roller

Total posts: 21
posted April 22, 2005 11:57 PM  
I don't really mind telling how much my engines cost because I look at it in a different way than some other people. When you spend 2500 on a motor and you blow up 5 a year that right there is well over 10000 so I would rather go ahead an get a good dependable motor with good horsepower. This motor is going on its 3rd season without being blown yet. I know a guy that blew up 14 in one year 2 years ago of course money wasnt a problem to him and he liked to give it a lot of liquid horsepower if you know what I mean (nitro). Anyways we priced everything brand new and it was around $35,000, with the used parts we spent $15,000 buying a new block and a couple of other things were also new.

dirtslinger66
Dirt Maniac

Total posts: 200
posted April 23, 2005 06:43 AM  
If you go to the auction in Des Moines Iowa in December you can get a complete sb2 from the cup guys for 7-9 grand

James Birmingham
Dirt Full Roller

Total posts: 28
posted April 24, 2005 08:26 AM  
My 2 cents. What I final say was the comparison of HP to a drag or oval motor. Ultimate HP is not always the answer. Torque is what drags the load up through the RPM range. Key here is range. If you understand the Cam term "area under the curve" then the "Torque Curve" will have the answer to the power everyone is seeking here. The smoothness vs the ultimate power peak.

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