Is a dyno tune worth the money?

[VRYQUIK]

Here is a good example of why dyno tuning is so important.

This customer's engine was built by another shop. The customer entered it in a local dyno shootout last year and the dyno graph showed that it had 113 TQ and 113 HP. It is a 2003 RK, 103 ci, HTCC heads and pistons, SE 258 cams, Stock T/B and injectors, Rinehart True Duals, SE Heavy Breather, roller rockers...
First thing that you need to realize is that the stock injectors cannot provide enough fuel to make 113 HP.

I use a SuperFlow Dynamometer using the "true" SAE formula. The dyno results are always lower than Dyno Jet numbers. This link will explain why: The Truth About Dynamometers.

This is the Before Dyno Graph. The bike was very lean through all loads and throttle positions. The 100% throttle was so lean that it went off of the AFR scale.


After trying to adjust the AFR, the higher RPMs still ran excessively lean.
The injectors were maxed out. We installed larger flowing injectors.

This is the After Dyno Graph



We normally charge $250.00 for a dyno tune. This customer not only gained
14.7 TQ / 11.9 HP but also has the peace of mind that the engine won't be damaged due to running too lean.
$250.00 well spent!

BTW, the Dyno Jet graph would have have been around 124 TQ / 115 HP.

[Gas Man]

I hear ya on the debate on dynos. Here's the problem. I don't care how "more accurate" the SuperFlow dyno is... if 90% of everybody else uses dynojet numbers than it is set as the standard. That allows people to compare apples to apples. I had a bike dyno'ed on a superflow once and will never again. Cause at the end of the day all I knew was that the bike was running good but had no idea how it compared to other motors built to different or even similar specs.

[VRYQUIK]

Originally Posted by Gas Man

I hear ya on the debate on dynos. Here's the problem. I don't care how "more accurate" the SuperFlow dyno is... if 90% of everybody else uses dynojet numbers than it is set as the standard. That allows people to compare apples to apples. I had a bike dyno'ed on a superflow once and will never again. Cause at the end of the day all I knew was that the bike was running good but had no idea how it compared to other motors built to different or even similar specs.

Sorry, but I would have to disagree.
Here is the proof: Below are a few graphs from dyno shootouts using my bike at different HD dealers that were all using Dynojet dyamometers.










I don't see the comparison.

Here is the direct link to the article posted in Hot Rod Magazine about why Dynojet has an increased power numbers:
The Story Behind the Dynojet Chassis Dyno - The Truth Meter - Hot Rod Magazine

Basically, it comes down to truth or fiction. I or anyone else can change the correction formula on any dynamometer (if they know how). After tuning the bike, I changed the formula to read +15% and +20% to show the customer what the Dynojet would be showing. I'll scan and post them tonight on this thread.

Remember, this same bike had 113 TQ / 113 HP on a shootout using a dynojet. That can not be done when using stock injectors.

Here is a video link of that bike at that shootout.

YouTube - ROAD KING DYNO SHOOTOUT 06/14/2008

[mstngjoe]

IMHO, the only valid way to compare builds is to run them back to back on the same dyno, day & operator.

The dyno is a tool. If it's not properly used and calibrated your test results don't mean much.

My previous hobby was Mustangs and small block Ford engines. All of the tuning on my cars was done at Loynings Engine Service in Portland. Doug Esterbrook ran the Superflow dyno and was a well known and respected tuner. I never worried too much about how my numbers might have compared to Dynojet numbers. I knew my engines were optimized and that was my goal.

I totally understand how numbers can be inflated by some operators. It does no one any good. Unless of course your only purpose is bench racing.

Putting out numbers that injectors or carbs can't support just makes the opertor look stupid.....or dishonest.

[VRYQUIK]

Originally Posted by mstngjoe

IMHO, the only valid way to compare builds is to run them back to back on the same dyno, day & operator.

The dyno is a tool. If it's not properly used and calibrated your test results don't mean much.

My previous hobby was Mustangs and small block Ford engines. All of the tuning on my cars was done at Loynings Engine Service in Portland. Doug Esterbrook ran the Superflow dyno and was a well known and respected tuner. I never worried too much about how my numbers might have compared to Dynojet numbers. I knew my engines were optimized and that was my goal.

I totally understand how numbers can be inflated by some operators. It does no one any good. Unless of course your only purpose is bench racing.

Putting out numbers that injectors or carbs can't support just makes the opertor look stupid.....or dishonest.

I totally agree!

I've been thinking about finding someone with a stock 2009 bike that would go to all of the local HD dealers and have them to dyno the bike, get the comparisons and share them with the dealers. Maybe they would all agree to use the same standards and formulas.

This would be a good idea to create an dyno organization where the dealers that are members, can advertise that you will have "close" to the same readings as the other dealers that are members. Every six months or every year there should be a bike taken around to the dealers to make sure that they are still in comparison.

Or I guess I could offer a "Pick Your Horsepower" service that you can tell me how much hp you want and I'll dyno the bike and change the formula to fit the numbers that they request so they will have a paper that they can show their freinds.

[bobl]

I have a 2009 road glide screaming eagle. With super traps slip-ons. The head tec. said I should put it on his dyno. Well this ashole ran it 25 times and then gives it back and said it’s ready to go. Hell I could not even leave the shop ,hit the throttle and had nothing. So we went back in for another run. And guess what? Same dam thing. HE says he has to drill a hole in the exhaust to put the o2.rod in . I thought it was a closed loop set up. Can anybody shed some light on this?

[VRYQUIK]

Originally Posted by bobl

I have a 2009 road glide screaming eagle. With super traps slip-ons. The head tec. said I should put it on his dyno. Well this ashole ran it 25 times and then gives it back and said it’s ready to go. Hell I could not even leave the shop ,hit the throttle and had nothing. So we went back in for another run. And guess what? Same dam thing. HE says he has to drill a hole in the exhaust to put the o2.rod in . I thought it was a closed loop set up. Can anybody shed some light on this?

The closed loop bikes are easier to tune than the non-O2 sensor bikes.
At least it is with my dyno. Basically you start with setting a base map with the AFR page with all of the cells at 13:1 . This will take it out of closed loop. Remove the O2 sensor from which ever cylinder that you are tuning at the time. Leave the O2 sensor plugged in. Install the dyno O2 sensor in place of the bike's O2 sensor. The Dynojets may not be able to do this depending on the type of AFR unit that they are using. Map the bike so it will be at 13:1 at all throttle positions. After it is mapped to 13:1, change the cells on the AFR page to the desired ratio. I will usually change the cells to 14.6:1 (which puts the bike back into closed loop on those cells). I would leave the AFR on idle at 13:1. I would also leave the high load areas at 13:1.

This set up will give you the best fuel mileage during cruising and then you will have the best mixture for power under load acceleration.

[bobl]

thank for the feedback . But can you answer why the tec. wants to drill holes in the back of the super traps ?

[mstngjoe]

The baffles in the muffler are probably preventing the air fuel sensor from entering far enough into the exhaust system for a valid reading.

My '07 Sportster had the same issue with some Cycle Shack slip-ons. My Indy shoved a 3/8" drill bit thru so the sensor would be able to pick up more valid readings.

[mstngjoe]

Originally Posted by VRYQUIK

I totally agree!

I've been thinking about finding someone with a stock 2009 bike that would go to all of the local HD dealers and have them to dyno the bike, get the comparisons and share them with the dealers. Maybe they would all agree to use the same standards and formulas.

This would be a good idea to create an dyno organization where the dealers that are members, can advertise that you will have "close" to the same readings as the other dealers that are members. Every six months or every year there should be a bike taken around to the dealers to make sure that they are still in comparison.

Or I guess I could offer a "Pick Your Horsepower" service that you can tell me how much hp you want and I'll dyno the bike and change the formula to fit the numbers that they request so they will have a paper that they can show their freinds.

Never happen.

Most dealers and tuners will not admit they don't give out accurate numbers or don't know how to calibrate or tune.

And the ones that know their numbers are valid don't give two ****s about the others.

It is what it is.......the riders that just care about the numbers will gravitate to the "tuners" that give the desired print out. Those of us that want to optimize our bikes will seek out and find the pros that do it right.

I don't have to prove my dick is bigger......if it's performance is optimized that's good enough for me.