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Anyone ever used a chassis dyno to tune their car???
#1
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??

Kevin

1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

[Image: 28ivsix.png]




                                                                                             
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#2
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

1971 Boss 351  
1972 Q code 4 speed convertible 
1971 Mustang Sportsroof  351-2V FMX 
1973 Mach 1 (parts car)
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#3
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.

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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#4
Boss1Ray;170052 Wrote: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.
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#5
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.

1971 Mustang fastback: 10.3:1 C90E 408W hydroller - CDAN4 EEC-V w/EDIS8, girdled, lowered and caged
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#6
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. Wink Big Grin 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.

Eric

[Image: mach1sig2.gif]
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#7
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.
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#8
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 shit on the street. I went back to the smaller jets so it ran nice on the street.

Rick Bombard
1971 Grabber Green Mach 1 351C 4V
2013 Race Red California Special Convertible
1973 Medium Copper Metallic Convertible 302 4V     SOLD
1953 F-100 project

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#9
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"Big Grin 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 Big Grin Thanks again guys, can always count on you guys for some insight!

Kevin

1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

[Image: 28ivsix.png]




                                                                                             
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#10
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.

1971 Mustang fastback: 10.3:1 C90E 408W hydroller - CDAN4 EEC-V w/EDIS8, girdled, lowered and caged
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