Guys, need your help......

Link to results slip below, nowhere near what was expected need help if am reading wrong or need to try a different dyno.

Guys, need your help......

Link to results slip below, nowhere near what was expected need help if am reading wrong or need to try a different dyno.

http://rides.webshots.com/photo/2634...53427645HOIVYL

Dyno Dynamcs aka ( Heartbreaker ) Rolling Road

330lb ft Torque @ flywheel

260.5 hp @ flywheel

If i take 20% loss off that for drag, tansmission etc only just over 200RWHP........

The RR tech took her for a spin and said great drive really good low down torque and feels about rightfor a 300RWHP car..... but figures do not agree..!

 

man, something isn't right there. That's waaaayyyy low. Do you have a plugged cat or is the car running on 6 cylinders?!! Did they dyno it in the right gear?

My car dyno'd at the wheels in the 338-342 range on 3 back to back to back passes.

 

Dynoed with TC off, 4th gear on j gate.... but he did say struggled to keep it in one gear...?... My thoughts is that the dyno is wrong, car seems to be fine and running well. There is another dyno about two hours or so away going to have a re-run there just to check i think, Before i look at the car itself. Thanks

 

Hit the drag strip, check your trap speed (mph) for whats potentially a better measure of power and improvements over stock.

 

I think you've got things backwards. A chassis dyno measures torque and speed at the rear wheels and not at the engine flywheel. You should add 'X' percentage to calculate flywheel numbers, not subtract.

 

Dyno Dynamics are notoriously known as "heart-breaker" dynos. They give low numbers, not sure how they calculate them. Look it up on Google. Try finding a place that has a Mustang Dyno.

 

I am confused Mikey, lol.... the figures on the print out i have say 330 & 260@flywheel are you saying i should add 20% to this to get correct figure...?

 

The picture you've posted is very blurry- camera must have been drunk. Maybe scan it instead of a picture- or put your camera on macro mode to take a clear close up.

In any case, no chassis dyno directly measures flywheel torque, only rear wheel. Possibly they call the rotating drum the wheels rest on 'a flywheel'?

 

Indeed, although the dyno sheet reads "flywheel" , it is in fact wheel horsepower, and it's only labelled flywheel for whatever reason, i have noticed this on dyno dynamics and dynapack dyno's read outs as well.

Add the 20% to your values, there is NO WAY the read out applied a minus correction factor in an attempt to show you real "flywheel" horsepower.

Based on your current numbers posted of 330 wheel torque, seems like it's about right for the kind of dyno you were on.

I'm not sure why STR owners keep going to dyno shops thinking they're going to get anything other than disappointing results. Between the electronics and drivetrain loss, you're only in for heartbreak.

Trap speeds at the track (MPH) says it all!

 

That is the explanation i needed, all wanted was a baseline from the dyno to see where i am at and what future upgrades bring.

My Proscan 0-60 time via my OBD and PC read 4.9secs on my last run, need to do a 1/4 mile timing and see what it throws up, nearest strip is Santa Pod 4hrs away...?.... but car seems to go well and pull well that is ultimately all that matters in reality..!

 

Your modded STR is making somewhere in the neighborhood of 360-370 rwhp. without full disengagement of DSC, this car is not able to be accurately dynoed. The dyno operator noticed something awry by his shifty 4th gear observation.

 

these cars are tough to dyno because they always want to downshift from 4th to third.

I've heard the dyno dynamics are about 12% low; which still puts you less than 300 rwhp. The 360-370 figure is pretty optomistic. Do any of your friends have the applications on their phone where they can calculate rough hp based off acceleration #'s and weight? Since there's not many dyno's and the track is too far, maybe that will work.

 

These cars only want to down shift if the operator floors it before around 4200 rpm or so. The downshift will not happen later any more obviously, so there you have a clean measurement. There is nothing magical here…

Hard to judge this dual drum per wheel dyno, i prefer dynos that have only 1 drum per wheel. Runs in 4th gear could take longer due to the higher resistance of the 2 small drums per wheel, causing more heat buildup in the intercooler system for insatance and thus power loss.

Here is an example of a dyno dynamics run, with a relativly similar car/setup:



Many operators display a flywheel hp figure; this can be either based on a calculation (which dyno dynamics use) or on losses measured during coasting. Anyway, what you see on the print out is what the operator selects to print. If unsure, ask them what they printed, and ask a true rwhp printout.

Also you can’t make out anything from the dyno slip, so can’t make any further comments.

 

A better image of the slip here for you all to have a gander at....



Will maybe try a run on my Proscan PC based system and see what that throws out as a comparison.

 

From 4500 rpm your power isn't even growing anymore, so eventough if the numbers where low, it should have grown there. Maybe it was a bad run with heatsoaked intercooler.

Did you do just 1 run? Didn't they measure you a/f ratio (so important to always ask for !). Have you checked your boost pressure? All that info could help explain the results.

Bytheway, KenneBell doesn't recommend the gator back belts, so maybe even some belt slip could have played a role (boost check would have shown this).

What size belt do you use?

 

For me that site is unusable as when I click to look at the image larger it does something stupid. I'll try to upload just the image below.

I don't know what the Dyno Dynamics machine is actually doing to show what it calls "flywheel ..." but clearly it's not really displaying any such thing if they didn't unbolt the trans and attach the machine to the flywheel LOL (So, kinda pointless BS. Just adds confusion.)

Well.... what's with the car (or possibly the dyno)? From the few others I've seen, the TQ curve looks wrong for an STR. Also the peak HP looks to be at too low RPM.

Don't expect to be within 20% with any dyno app (PC, smartphone or whatever).

 

Thanks guys,

Clearly becoming apparent this dyno was worthless....lol

The run was one single run, hot engine, bonnet down with single fan... the slip says intake temp @23 degrees, tie that in with a uprated pulley spinning the charger faster and heatsoak sets in as Andre said. As above posters have said car does not reach peak RPM for Peak HP output. Lots of anomolies plus no idea what a flywheel figure is, if i take it as RWHP the heatsoak would explain slight down in torque and the major down on HP.

Avos belt fitted with uprated pulley by tuner he fits them with the upgrades and has never had issue with them on the Eaton, he did say though the higher spinning/heating on the heaton will help low down torque but could be a trade against outright BHP.

Water injection and better cooling/airflow may be the answer to get what i should be getting...?

I think a new run somewhere else, with adequate cooling and ask the right questions is in order

 

If we dyno proved that a modded air intake tube with K&N a/f alone increases rwhp by 15 hp, why isn't it concievable that a 1.7 lb pulley and hi-flow cats add an additional 15 to 25 rwhp? If we all agreed Jaguars' and our own testing revealed a stock STR puts down between 330 and 340 rwhp, why is 360 to 370 rwhp optimistic? The modded air intake tube alone brings a stock 330 rwhp STR to 345 rwhp. Forum members track runs with K&N a/f, 3 pulley, and hi-flow cats yielded high 12 second 1/4 mile times. Most of us admit dynoing these cars is difficult due to DSC and trans. shift sequences. As one of our members in this thread suggested, track times are the ultimate measurement of our efforts. I for one stand by 370+ rwhp (450+ chp) with the mods presently available to the STR.

 

There are not many that actually do dynos/check the true power, and before you did this you where proably happy with the pulley, so even if he would have installed a couple it doesn't mean there aren't any issues possible. He could prove this if he would have some dynos, so that would be a good question anyhow.

You can check yourself the belt partno, or ask your tuner which belt, as I wouldn't be surprised if one is choosen that hasn't an ideal lentgh.

 

As always great feedback and help guys....!... I am currently in dialogue with a Paramount Performance Jag Tuner, he has done lot's of STR tuning and rolling road work. I have sent my dyno sheet for his perusal and i am booking a day with him for a new run/tuning runs on a Mustang dyno in Bromsgrove about 3hrs from me, with him and the tuning expert. Will be a couple of weeks before they can book me in, so while i am info gathering can you think of anything else i can question them on... thanks in advance and i will post new results up when they happen as this will be valuable to us all.