Dyno do’s and Dyno don’ts

[RecklessWOT]

A decent dyno shop takes the time to make sure they're doing everything right so they don't ruin your stuff. I have only ever had cars on a chassis dyno so I can't specifically tell you what happens on an engine dyno, but I do know the first time I ever had my car tuned I was actually turned away and had to come back because they inspected my car before doing anything and they found a soft radiator hose and a questionable wheel bearing, they didn't want to risk any sort of failure so they asked me to come back when I had taken care of it. I can't imagine the engine dyno guys would be much different. Sure they're not gonna take the engine apart and inspect how you built it, but they're not just gonna slap it on there and hammer the **** out of it and say "oh well not my problem" when they break it. I feel like if it breaks it would be because of something wrong with your setup, if you know you built a good engine then there's no reason it should break. Really all they're doing is running it through the RPMs a handful of times and making adjustments here and there, no worse than anything you will do on the street. Doing a big fat burnout probably puts more stress on it than using a dymamometer. Can't be nearly as bad as one day at a drag strip

 

[RecklessWOT]

The worries of something failing are real and it's not always the engine that fails. I think sometimes they hold it too long and it fails. Them having no responsibility at all bothers me too.

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A lot of these look like portable dynos at car shows and such, obviously wouldn't trust something like that. The supra in the beginning was probably pushing 1000hp like most of them are and who knows the rear end from 1993 might have given out. That would've happened on the street too. Some of them looked like a failure of the way the car was secured to the machine, others it looks like the machine itself failed- in those cases the shop would most definitely be liable regardless of what they made you sign. And for the tire blowing out etc, shame on the shop for not checking for something as simple as tire pressure. The truck that burst into flames and the Hondas who popped their engines, I'm willing to bet there was a problem with the way the engine was built or something else about their setup which also would've happened on the street either way. If you have a good car/engine, I can't see why the dyno would be what breaks it. More than likely it broke simply as the result of being revved up which will happen the first time you drive it hard

 

[82sbshortbed]

A decent dyno shop takes the time to make sure they're doing everything right so they don't ruin your stuff. I have only ever had cars on a chassis dyno so I can't specifically tell you what happens on an engine dyno, but I do know the first time I ever had my car tuned I was actually turned away and had to come back because they inspected my car before doing anything and they found a soft radiator hose and a questionable wheel bearing, they didn't want to risk any sort of failure so they asked me to come back when I had taken care of it. I can't imagine the engine dyno guys would be much different. Sure they're not gonna take the engine apart and inspect how you built it, but they're not just gonna slap it on there and hammer the **** out of it and say "oh well not my problem" when they break it. I feel like if it breaks it would be because of something wrong with your setup, if you know you built a good engine then there's no reason it should break. Really all they're doing is running it through the RPMs a handful of times and making adjustments here and there, no worse than anything you will do on the street. Doing a big fat burnout probably puts more stress on it than using a dymamometer. Can't be nearly as bad as one day at a drag strip

A lot of these look like portable dynos at car shows and such, obviously wouldn't trust something like that. The supra in the beginning was probably pushing 1000hp like most of them are and who knows the rear end from 1993 might have given out. That would've happened on the street too. Some of them looked like a failure of the way the car was secured to the machine, others it looks like the machine itself failed- in those cases the shop would most definitely be liable regardless of what they made you sign. And for the tire blowing out etc, shame on the shop for not checking for something as simple as tire pressure. The truck that burst into flames and the Hondas who popped their engines, I'm willing to bet there was a problem with the way the engine was built or something else about their setup which also would've happened on the street either way. If you have a good car/engine, I can't see why the dyno would be what breaks it. More than likely it broke simply as the result of being revved up which will happen the first time you drive it hard

These are two good points. The ones the fell off would be the shops fault. But, I feel that they Rev it way up and hold it too long. If I could be there and tell them I'm not looking to Rev the **** outta this this and run a hundred and fifty miles an hour.

My BBC 454 revs out at 5,500. I wouldn't want them going over 5k really. I feel as you said if they ran thru the gears not over Rev it or hold it pegged it would be OK.

I think it's a risk you gotta be willing to take.

 

[RecklessWOT]

These are two good points. The ones the fell off would be the shops fault. But, I feel that they Rev it way up and hold it too long. If I could be there and tell them I'm not looking to Rev the **** outta this this and run a hundred and fifty miles an hour.

My BBC 454 revs out at 5,500. I wouldn't want them going over 5k really. I feel as you said if they ran thru the gears not over Rev it or hold it pegged it would be OK.

I think it's a risk you gotta be willing to take.

well they have to run it through the entire RPM range to find where the engine makes its peak power. If they only revved it up to 2 or 3k and short shifted it every time the dyno would read out as your peak output being like 100hp. Your engine does not make full power all the time, there is a certain point where it hits its max and then drops off. So to be able to find that point they need to get it all the way up there. They don't get it to redline and leave it there, they smoothly roll on the throttle until pretty much redline and let off once it gets there. They don't go through all the gears and rev it up to 150mph, they just need to shift through the lower gears to reach whichever gear is 1 to 1 as it is the only gear that will produce an accurate reading, and obviously they can't start in 3rd or 4th gear.

If your 454 revs out at 5500rpm then it is capable of safely hitting 5500rpm (if not more) for short periods of time. I wouldn't suggest leaving a big block at 5 grand for minutes on end, but if you're afraid your big block is gonna blow up as soon as they rev it out at a dyno shop then it must not be built very well. If you really wouldn't want them to rev it up on the dyno then there is no point in even bringing it to them, you won't get complete results, and they would not be able to achieve an accurate tune. Do you honestly never rev it out on the street? Redline does not make an engine magically grenade, a healthy engine can handle it even on a somewhat regular basis. I get my engines damn near redline every time I drive them and they're all okay- they all have fairly high miles and they take it just fine.

It's one thing to take care of your engine and treat it right I'm not suggesting you abuse the poor thing, but if you can't rev it up once in a while then what's the point of even having a big powerful engine if you can't use all its power?

 

[CoggedBelt75]

If those of you who would please list the dyno shops you used and location. Both chassis dyno and engine dyno.

In 2002 my 1st one was HP Tuners in OKC. In 2007 it was at SW Tuners, also in OKC. I’ve never owned a trailer, so a buddy offered to take us on the trip.

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Both are long gone now. With most of the Street Outlaw guys opening up shops now, guess everyone is going to them. Of course at each one, I had to sign a waiver saying they’re not responsible for damage. I understand this as it would be easy for a customer come in knowing they already had some serious issues and then turn around expecting the shop to make good with what ever happened.
I’m still not sure why you’re wanting to do this tho. If for tuning purposes, IMO research the area shops and pick the one you’re most comfortable with. Reviews are nice, but can also be created by the shop itself. In my case, the best thing I did was call the guy and talk to him. Feel him out, so to speak.

If your just curious how much it’s putting out, set your expectations a bit low. On the 1st go around I wanted some figures at the end of the tune. I thought the truck was fairly up there in the numbers department. He asked if I wanted real world numbers. What does mean, I had to ask. He basically creates a load to mimic the street. So could he inflate the numbers? Yes was the answer. Guess that’s all well & good if you’re bench racing. Real world for me. At the end, a total let down. The bubble I had going in was popped coming out. The second time I didn’t want to know any numbers that were acquired from the tune. And still don’t care to either.

 

[Matt69olds]

Every chassis dyno I have used makes you sign a waiver, they ask a few questions about your build, and the ask what rpm you want the pull the stop. However, I would think any competent dyno operator would stop the pull whether the engine is done making power. If you tell them the redline is 5500, and the engine is obviously done by 5, there is no point pushing it any harder.

 

[BigDaddy72]

I have also been told many many times that the numbers can be inflated.

Another mystery concerning dyno tuning I guess.

Big numbers are always great but the engine is going to make what it makes after the optimal tune and that’s what I would be most interested in. Squeezing as much out of a certain combo as you safely can. Ie: timing and such being a tad on he conservative side.

For me running the afr 496 down the track isn’t an option as it is in a lifted k3500 quad cab dually with super swampers.

It will not be hot rodded. Only occasionally used to haul my 28’ enclosed trailer.

So a dyno tune is appealing from the point of having all the guess work taken out and not leaving hp and tq on the table.

Just used as a scientific tuning tool.

You said you were disappointed I understand that. That is why when bucket asked what kind of grunt did I think it would make I said possibly 500 hp and 550 tq.

Stating anything more than those numbers (guesses)in my honest opinion for my 496 build would be more hopeful than realistic.

 

[Paladin]

Up until this thread came along I have generally regretted never having my engine dyno'ed when I completed my build, as I wanted to see those awesome magic numbers of HP and Torque that were dancing around in my head. That regret is now gone!!!! I am now satisfied knowing that it runs very well, screams like a banshee when I get on it and launches very nicely, and that's in a Dually! What do I need those #'s for? Especially when they can be enhanced or degraded by someone who doesn't have a buck invested in it and can tear it up for me with no liability on their part. Just doesn't make sense to me now.

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[BigDaddy72]

Sure looks cool with the double barrel on top!!

 

[Paladin]

Sure looks cool with the double barrel on top!!

Thank you Sir!!

 

[Salty Crusty]

I particularly like the USMC stickers on the butterfly, very nice touch!!!
Damn good lookin' mill, attaboy!

 

[SquareRoot]

The USMC stickers add 50+HP! Semper fi, carry on Devil Dawg.

 

[QBuff02]

@Paladin Teufel Hunden!

 

[Salty Crusty]

Paint tips and secrets? Shiny and smooth not only looks a lot better, it's so much easier to clean than rough. And good on you for not painting the fasteners. I don't care if it's not the "factory" look, it's a lot cleaner and more professional looking with fastener heads exposed.

 

[Paladin]

@Paladin Teufel Hunden!

OooooRahhhhhhhh!!!!!!!!!