Anyone ever used a chassis dyno to tune their car???

[turtle5353]

Hey guys just wondering if anyone has any experience with tuning their motors with a chassis dyno? Are they a good way to tune? Since I Got my motor done in my car over the summer I haven't had a chance to completely tune and rejet the carb and completely dial in the timing. I thought that I could take it to a chassis dyno and get it really dialed in. I was going to talk to my engine builder and see if he wanted to ride along and go with me to help tune it. he is a good guy and cool as hell so im sure he will be up for it. I was able to find a local speed shop that has a dyno that you can use for $100/hr and $50 every half hr after that. Whish didn't seem unreasonable to me. Also I am really curious to see the kind of HP I have at the rear wheels.

What do you guys think??

 

[Boss1Ray]

Google "chassis dyno fails" -

For that small improvement, I would pass. I guess if you are intent on squeezing every last HP from your build, it would be OK. But I would be super careful.

Ray

 

[Jeff73Mach1]

I agree that Chassis dynos do put a lot of stress on the drivetrain. I would suggest that for similar money you could install a oxygen sensor and an air fuel gauge and accomplish the same thing. Also, one problem on a Chassis dyno is you can only tune with what you have on hand. If the carb size is off, you aren't likely to have a selection on hand-if the distributor needs to be recurved, that may not be possible onsite, for anything other than minor changes, I think it is easier to work with the air fuel gauge and have time on your side.

There are apps for your phone that will estimate rear wheel horsepower and believe it or not some of them seem to be pretty accurate iof you follow the instructons.

 

[mdan575]

Google "chassis dyno fails" -

For that small improvement, I would pass. I guess if you are intent on squeezing every last HP from your build, it would be OK. But I would be super careful.

Ray

Accidents happen bottom line. Just because videos can be found of accidents doesn't make something a bad idea. Using a well respected safe smart business is always a better idea than a fly by night operation. A chassis dyno is a good way to dial in a motor without the sometimes illegal methods used on the street. Also a generally safe way to dial in Air/Fuel Mixture to safe margins with a Wideband O2 Sensor. Yes it can help squeeze a little extra horsepower out of an engine. It can also allow a good tuner to easily see the power curve and air fuel mixture side by side to properly adjust advance curve, timing and fuel for optimal mixture.

 

[Mesozoic]

I've done a lot of dyno tuning. I agree, it's best to achieve a baseline by using a WBO2 prior to going to a dyno. I've blown up a motor or 2 by not having a decent base tune with enough fuel in different parts of the curve. The dyno is extremely stressful for the drivetrain and will kill an engine pretty fast if things aren't in a pretty good state to begin with.

 

[Mister 4x4]

As for what Jeff said, "... one problem on a Chassis dyno is you can only tune with what you have on hand." Well, I would think that kind of applies whether it's a chassis dyno or engine dyno. rofl But he's right.

We have a Mustang Dynamometer at the Auto Hobby Shop - as you may have seen in several of my pictures, it makes a dandy work bench. We don't have the manpower to actually run the dyno AND keep the shop running on the weekends. We need to come up with a "Dyno Day" kind of thing, but the MWR advertising/marketing people suck, and it wouldn't get promoted correctly. Oh well.

Ours is 'above ground,' and placed directly at the front of one of the 12,000 lb drive-on lifts. Back onto the lift, raise it up, back-up onto the roller, and strap that sucker down. It's crazy watching the car run... and just a bit scary as well (if those straps fail.... it's gonna be a helluva ride after the launch from 40 inches up after reaching the end of the lift.

Typically, someone brings their car, puts it up on the dyno, has 3 runs, then sulks off because they didn't get the numbers they wanted - never saw anybody come back with any improvements, either.

On one occasion we ran the dyno a few years back, some tuner kid (from Dyess AFB) came down with his ricer buddies and put his '89 Dodge Conquest on the dyno. His buddies all had "fart cannon & decal" upgrades, and were pretty much just wasting their time. He had built the crap out of the 2.2L intercooled/turbo 4-banger, and was pulling a solid 265hp on the first run. He had his laptop plugged in, made some adjustments, and pulled 289 the next run. Then he tweaked a few more things, and put up 301. I stepped away to do something for about 20 minutes, but when I came back, his final run showed 317rwhp - on an '89 Conquest! He squeezed out another 50+rwhp with his laptop. Of course, his buddies were in awe (as were we) and asking all sorts of question on how they could make there's work like that as well.

But yeah... it's possible to use a chassis dyno to tune.

You could always take a couple of carbs, jet kits, or whatever to try them out. If there's not a high demand for the dyno while you're there, you could probably try out a couple of different set-ups and tweak as you go. To know for sure though, pull the engine and put it on an engine dyno.

 

[mdan575]

Wish I could be stationed at a post with a chassis dyno at the Auto Craft Shop. Hell I wish I could be stationed at a post with a reasonable auto craft shop. After leaving Fort Hood in 2003 I haven't see a reasonable one since.

 

[71mach351]

I put mine on a chassis dyno after an engine rebuild about 10 years ago. Tuned it great for highest hp but it drove like **** on the street. I went back to the smaller jets so it ran nice on the street.

 

[turtle5353]

Thanks for all the input guys!!! I was just at my engine builders place tonight and talked to him about it. He knows the guy I was talking to and said his shop is top notch. Dyno is about 2 years old and very nice shop and very knowledgeable. He said he wants to tune it one more time just to smooth out a few things and he said I could definitely fine tune it on the dyno, but asked "do you really need 10 -15 hp more when you have over 550 now on the street?" I said "Probably not but it would be fun" He even stated that I may lose some driveablity with a full out hp tune. So im probably gonna be happy with what I got. We already detuned the motor during the build to make it pump gas and street friendly. He did say he wanted to change the jets and fine tune the timing since its broke in now. So once the weather breaks I will go see him and run the wheels off it this summer Thanks again guys, can always count on you guys for some insight!

 

[Mesozoic]

You can always tune with a WBO2 to fine tune things. I'm was generating roughly 500 hp (408 Wheezer) with a Speed Demon 750cfm mechanical secondary carb, Torker II intake, and managed to get 25 mpg on the highway spinning at 4000 RPM after one day of tuning with the wideband.

 

[turtle5353]

You can always tune with a WBO2 to fine tune things. I'm was generating roughly 500 hp (408 Wheezer) with a Speed Demon 750cfm mechanical secondary carb, Torker II intake, and managed to get 25 mpg on the highway spinning at 4000 RPM after one day of tuning with the wideband.

NICE! good to know...... Im running a 850 quick fuel and really close to single digit MPG..... but my right foot gets pretty heavy anytime im in the mustang !!

 

[Mesozoic]

You can always tune with a WBO2 to fine tune things. I'm was generating roughly 500 hp (408 Wheezer) with a Speed Demon 750cfm mechanical secondary carb, Torker II intake, and managed to get 25 mpg on the highway spinning at 4000 RPM after one day of tuning with the wideband.

NICE! good to know...... Im running a 850 quick fuel and really close to single digit MPG..... but my right foot gets pretty heavy anytime im in the mustang !!

I should mention that I'm at 10.2:1 compression and was using a Mallory Unilite distributor with vacuum advance... I believe the vacuum advance is what helped the fuel economy when cruising unloaded by adding a ton of timing advance.

 

[MeZapU]

I dyno'd my 85 GT's 408 like this using a local dyno. I am happy with the 40hp gains with me making carb and timing adjustments, but was unhappy with the shop as I was always chasing them down to do the next run. At $100 an hour I expected them to be be pretty much at my beckon call.

But lousy management aside, it is a great tool.

Don't let the "abusive" rumors of the dyno scare you. If the engine won't last on the dyno, it certainly won't last on the street. Most often a fresh engine is broken-in on a chassis dyno. If the build is not up to par, leads to broken engines. Because the event is frequently filmed and posted all over the interweb, rumors spread that it was the dyno's fault. A smooth and long 4-th gear pull is far less abusive than a big burnout, followed by blipping it off the redline through all the gears, time after time.

 

[Jeff73Mach1]

you got me, at any dyno you are limited to your parts on hand while spending a hundred bucks an hour, as opposed to wide band / air fuel gauge and sensors that you pay under 200 for and can constantly view and refine your tune to best suit your driving.

A dyno isn't harder on a car than a quarter mile run, and it can be much milder if the operator so chooses-but breakage occurs at the limit wherever you are, so even during very spirited driving we aren't holding the throttle wide open for more than 15 or 20 seconds-

I tuned my prior engine on a chassis dyno-all the tuning we did led us back to the original settings as we could find no more power anywhere.

 

[Boss1Ray]

Google "chassis dyno fails" -

For that small improvement, I would pass. I guess if you are intent on squeezing every last HP from your build, it would be OK. But I would be super careful.

Ray

Accidents happen bottom line. Just because videos can be found of accidents doesn't make something a bad idea. Using a well respected safe smart business is always a better idea than a fly by night operation. A chassis dyno is a good way to dial in a motor without the sometimes illegal methods used on the street. Also a generally safe way to dial in Air/Fuel Mixture to safe margins with a Wideband O2 Sensor. Yes it can help squeeze a little extra horsepower out of an engine. It can also allow a good tuner to easily see the power curve and air fuel mixture side by side to properly adjust advance curve, timing and fuel for optimal mixture.

Accidents happen... yes - but why? Good to know if and how they DO happen. - be aware. That's my point. To ignore is - well you know.

All chassis dynos are not the same. I've seen a few at car shows- the portable types and while some may be ok, I would be especially leary of those. As mdan575 said - go for a reputable shop. One with safety measures in place and good equipment. Straps, chains and other anchoring devices can and do fail.

I'd sure make sure your insurance covers you in case something breaks loose. The reputable chassis dyno shops will require you sign a disclaimer.

Everyone's threshold for an accident happening is different.

Do your own research and make your own best decisions.

For me - I can't justify the possibility of catastrophic failure vs other tuning methods.

I know I am getting older and safety is always up there high on my list.

Good luck.

Ray

 

[VegasFastback]

I'm just goin to leave this here. It's sketchy as hell but an interesting read

http://www.viragotech.com/fixit/Home-dynomometer%20using%20a%20Colortune,%20article%20by%20David%20Vizard.htm

 

[Mesozoic]

If you're serious about dyno tuning, avoid using the typical Dynojet systems and find a shop that has Dynapacks instead. They bolt directly onto the axle via various adapters, have much better software control, and are much more accurate than the older style "wheels in water" technology. These were my previous employer's choice of dyno and for a good reason.

 

[will e]

Any wide band sensors that log data (so I don't have to watch them while driving?)

 

[Mesozoic]

A cheap DataQ USB device on your laptop spliced into the WBO2 harness isn't a terrible amount of work and gets what you need. Alternatively, most of the EFI systems have tuning software that usually supports WBO2 datalogging, if you were going down that road.

The device I have in mind is this: http://www.dataq.com/products/startkit/di145.htm

This product is used by the Ford ECM tuning community, particularly those using the Binary Editor software.