[kevinca]

Okay,
This is going to sound silly to those of you who have dyno'd your call multiple times, but I'm nervous about dropping my car off tomorrow for dyno tuning.

My father had a Harley that he dynotuned multiple times while he owned it and blew a clutch on the dyno. When I told my father-in-law that I was getting it done, the first thing he asked is what guarantees is the shop making regarding blowing up my engine. People come from other states to this shop, but it doesn't change the fact that I'm nervous.

OK...enough whining, My question:
Do I have any recourse if my car is damaged while being dyno'd? From you guys experience, how often does a car get damaged on the dyno? As an addendum, I'm running an 8lb s/c on a 96 GSR.

My car will be there from Wednesday evening til Saturday morning. Someone please allay my apprhension.

 

[gotsomerevs]

they wont blow it up

 

[jent]

i have holded off dynoign my car for the same reason...i need my car and if the engine is f**ked i can't do anything...plus i don't want to damaged it esspissaly when i am going 0mph

 

[swiftllamagone]

no problems during my dyno session... i wouldn't worry...

my recommendation: be there when they do it... its a complete rush!

 

[Weston]

jent: the agreement they make you sign at PFI's dyno won't put your mind at ease, but I don't see how they could blow the engine if your ECU's revlimiter works. They just had me fill out some paperwork about the car and asked how high to rev it. I said 7k, and that's what they did. The dyno is just like you driving it down the highway with the pedal to the floor.

BTW, going to emissions is pretty similar to a dyno; for CO emissions stations, at least.

 

[Gvtec]

I've seen many a cars not be able to drive off a dyno. With faulty ignition systems and tuning settings, you can't blame the dyno operator. All he's doing is stnding on the throttle, just like you would on the street. People get too agressive on a dyno, attempting to set some new shop record. A dyno pass isn't going to blow a clutch or anything else. If the clutch is weak, it would tear up on the street just the same.

Every dyno I've seen makes you sign away your rights, to protect them from fools who think there is some safety net from poor tuning.

 

[sleeperls93]

I am visiting a dyno shop very soon, and wanted to know is it worth going considering I don't have a vafc or a fuel pressure regulator? All I have is skunk2 cam gears? can the current ecu fuel map be modified and reprogrammed with their wideband O2 sensor? Does the reprogramming of an ecu require chip burning? I obvioulsy don't have the slightest clue about dyno tuning, all I ultimately desire is a nice even and straight power curve throughout the midrange, and to peak power, without any dips, and a flat tourque curve, with the proper fueling along the way. Can the vtec crossover be manipulated without the vafc? I trust your honest opinions more then any shop owner, thanks alot
-Caesar

 

[kevinca]

GVtec -
I understand your point, but if my car has driven cleanly without a problem for 8 months now with its current setup and it can't drive off the dyno, then its the responsibility of the shop owner. I don't care what you sign away, you could bet I wouldn't let it rest if my car was ruined on that dyno.

Somehow I doubt that will occur, but Weston on a forced induction vehicle you can easily blow up the engine without ever touching the rev limiter.

That being said Gvtec, I will be getting a before and after dyno chart of the engine with and without the Hondata gasket. I believe I have a very similar setup to your vehicle so you'll get to see whether or not it will be worth your time to put on.

 

[MichaelDelaney]

make sure the oil level ,coolant, MTF, or any other fluids for that matter are topped up. prevent tire bounce off the rollers by making sure your tire pressure is in the normal range. check and tighten the lug nuts (60 lb ft). Tighten the master slave cylinder bolt to the clutch. check the wires and plugs. gap the plugs. Bring an extra bottle of oil and your basic tools...allen keys, pliers, torque wrench, timing light. It's like a day at the track. one of those dyno pulls is the equivalent of scampering down the 1/4 mile. People forget that. If you want to stop being nervous about it, then do basic preventative maintenance check before you go in...like I said in my dyno tuning article.

you wouldn't go to a test and tune or race day at the track without doing this. So if you are thumping the car at the dyno, make the same checks...

cheers

 

[MichaelDelaney]

BTW when you are there, make sure they use lotsa fans to cool off the engine. You may want to bring a couple bags of ice to cool off the IM...people laugh at me when I do it but I'm looking for consistency in the measurements and heat sinking can cause variation. If you are off by 2 whp from run to run that's one thing...but to be off by 5 whp from heat sinking, is not helpful when you are tuning. Look at Tony's dyno: 214 whp...he then let's the car cool down and she pulls 219 whp.

The oldest trick in the book is to milk the time since you are paying by the hr but make sure you do take the time to let her cool down after 3-4 pulls.

If it's a dynojet and they don't have a Winpep program to correct for temp and altitude then make sure you get the temp. and correction factor printed and everything in SAE whp and torque. Ask where the thermometer is located for ambient temp. in the shop.

When you are happy with the result of the final setup, do a pull through the gears as if you were doing a run...2nd, 3rd, and 4th. Do a printout of a dyno pull in 2nd , 3rd and in 4th. Get the acceleration data (change in speed vs time and change in speed vs rpm) from him. Get him to print the speed vs time as well as the standard hp/torque vs rpm. That way we can see how you transient.

If they have an air fuel ratio O2 sensor readout, get that hooked up before you start...they stick it in the tailpipe.


respect the safety instructions the operator tells you. If he says don't stand in a particular place then do it.

have fun and don't worry...do the maintenance check...tell the operator you don't want him anywhere near the fuel cut..no bouncing off the fuel cut please...

this is what it's all about...be smart about it but most of all , have fun out there...

 

[MichaelDelaney]

last point...if you don't make the hp you expect...don't blame the dyno operator...the dyno is just a monitor...like your computer monitor...it just shows you what it can measure...

it's not just about peak whp either...it's about the total average hp for the entire rpm range (area under the curve) and how fast your power climbs to peak and locating your powerband. As we have said here many times, you don't have to pray to the peak hp God. Look at the entire rpm range and for dips in torque...look at the air fuel ratio at those dips...that's what you need to fix...

BTW you sign a waiver at the beginning anyway....

 

[96_GSR]

Waivers mean nothing...If a shop blew up my motor on a dyno, they would get sued, and lose..Waivers are just pieces of paper to make people think they can't sue..You can sue ANYBODY!....

 

[Gvtec]

Where are you guys getting your legal advise from? People's Court?

kevinca: Did the dyno shop pay for the clutch on the Harley? I doubt it.

 

[MichaelDelaney]

Waivers mean nothing...If a shop blew up my motor on a dyno, they would get sued, and lose..Waivers are just pieces of paper to make people think they can't sue..You can sue ANYBODY!....

go right ahead and try....

all the guy did was hook up your car to a roller and put the throttle down in 4th gear to a presepcified rpm. If your clutch went on the dyno, it would have gone on the road the minute you punched it.

 

[MichaelDelaney]

unless the car was not strapped down properly or the guy was tuning your engine and did damage with the adjustment or he bounced off the fuel cut many times against your wishes and did damage, you aren't going to win a suit. The simple act of dynoing is no different from making a 1/4 mile run and so should not "break" the car unless it was already in a poor state of maintenance that would allow it to break eventually under hard driving. When you sign a waiver, you are signing the fact that you are allowing him to strap the car on properly and do the equivalent of a 1/4 mile run for each pull. it's like handing your keys over to someone, who knows how to shift and launch properly, to do a 1/4 mile run for you. that's what you are signing over.

 

[hootb18]

a waiver does mean something, but it doesnt excuse the operator for everything. basically what it does is say that if the operator doesnt do anything wrong, and the car breaks, i.e. clutch goes out because it would have gone out on the road anyways, then its not his fault and he is not responsible. but if the dyno operator does to something wrong, i.e. just held the throttle down and watched the needle like it was on a trampoline, then yes no question about it. you can sue his ass and that waiver isnt going to mean sh*t. think of the waiver as a contract between both of you. if you havent taken care of your car and something happens when he's tuning it that was out of his control, then his ass is covered. but if you have taken care of it and he does mess it up, then sue away.

 

[96_GSR]

I agree hoot!

 

[MichaelDelaney]

I'm glad we are all in agreement now....

 

[kevinca]

The shop is 80 miles away and I have to make money to pay for this stuff, hence I work and cannot be there for the tuning.

Next question then:

Would any of you just leave a car at a dyno shop without being there for the tuning?

BTW, I would never expect them to pay for a blown clutch, but I would if they leaned out the car too much and blew the engine. That's all I meant about recourse. If it's user error...

 

[MichaelDelaney]

yeah if he leaned the sh*t out of it..sure.

It really depends on how much you trust this guy. I personally would like to be present for the first time at a dyno shop I didn't know but if economics limits that option, then why don't you wait until you have the cash in hand and then go with the car then?...what's the rush?